man: Move man pages, source and result, into main/

part of cleaning up the root directory.

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diff --git a/man/gps.xml b/man/gps.xml
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+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gps.1'>
+<refentryinfo><date>9 Aug 2004</date></refentryinfo>
+<refmeta>
+<refentrytitle>gps</refentrytitle>
+<manvolnum>1</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>cgps</refname>
+<refname>gegps</refname>
+<refname>gps</refname>
+<refname>lcdgps</refname>
+<refname>xgps</refname>
+<refname>xgpsspeed</refname>
+<refpurpose>test clients for gpsd</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>cgps</command>
+      <arg choice='opt'>-D <replaceable>debug-level</replaceable></arg>
+      <arg choice='opt'>-h </arg>
+      <arg choice='opt'>-l <group><arg>d</arg><arg>m</arg><arg>s</arg></group></arg>
+      <arg choice='opt'>-m </arg>
+      <arg choice='opt'>-s </arg>
+      <arg choice='opt'>-u <group><arg>i</arg><arg>n</arg><arg>m</arg></group></arg>
+      <arg choice='opt'>-V </arg>
+      <group>
+	<replaceable>server</replaceable>
+	  <group>
+	    <replaceable>:port</replaceable>
+	      <group><replaceable>:device</replaceable></group>
+	  </group>
+      </group>
+</cmdsynopsis>
+<cmdsynopsis>
+  <command>gegps</command>
+      <arg choice='opt'>-d <replaceable>directory</replaceable></arg>
+      <arg choice='opt'>-h </arg>
+      <arg choice='opt'>-i </arg>
+      <arg choice='opt'>-V </arg>
+</cmdsynopsis>
+<cmdsynopsis>
+  <command>lcdgps</command>
+      <arg choice='opt'>-h </arg>
+      <arg choice='opt'>-j </arg>
+      <arg choice='opt'>-l <group><arg>d</arg><arg>m</arg><arg>s</arg></group></arg>
+      <arg choice='opt'>-s </arg>
+      <arg choice='opt'>-u <group><arg>i</arg><arg>n</arg><arg>m</arg></group></arg>
+      <arg choice='opt'>-V </arg>
+      <group>
+	<replaceable>server</replaceable>
+	  <group>
+	    <replaceable>:port</replaceable>
+	      <group><replaceable>:device</replaceable></group>
+	  </group>
+      </group>
+</cmdsynopsis>
+<cmdsynopsis>
+  <command>xgps</command>
+      <arg choice='opt'>-? </arg>
+      <arg choice='opt'>-D <replaceable>debug-level</replaceable></arg>
+      <arg choice='opt'>-h </arg>
+      <arg choice='opt'>-l <group><arg>d</arg><arg>m</arg><arg>s</arg></group></arg>
+      <arg choice='opt'>-u <group><arg>i</arg><arg>n</arg><arg>m</arg></group></arg>
+      <arg choice='opt'>-V </arg>
+      <group>
+	<replaceable>server</replaceable>
+	  <group>
+	    <replaceable>:port</replaceable>
+	      <group><replaceable>:device</replaceable></group>
+	  </group>
+      </group>
+</cmdsynopsis>
+<cmdsynopsis>
+  <command>xgpsspeed</command>
+      <arg choice='opt'>--debug <replaceable>debug-level</replaceable></arg>
+      <arg choice='opt'>--device <replaceable>device</replaceable></arg>
+      <arg choice='opt'>-h </arg>
+      <arg choice='opt'>--host <replaceable>host</replaceable></arg>
+      <arg choice='opt'>--landspeed </arg>
+      <arg choice='opt'>--maxspeed <replaceable>maxspeed</replaceable></arg>
+      <arg choice='opt'>--nautical </arg>
+      <arg choice='opt'>--port <replaceable>port</replaceable></arg>
+      <arg choice='opt'>--speedunits
+	      <group choice='req'>
+		      <arg>mph</arg><arg>kph</arg><arg>knots</arg>
+              </group>
+      </arg>
+      <arg choice='opt'>-V </arg>
+      <group>
+	<replaceable>server</replaceable>
+	  <group>
+	    <replaceable>:port</replaceable>
+	      <group><replaceable>:device</replaceable></group>
+	  </group>
+      </group>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para>These are the demonstration clients shipped with
+<application>gpsd</application>. They have some common options:</para>
+
+<para>The <option>-h</option> option causes each client to emit a summary of its
+options and then exit.</para>
+
+<para>The <option>-V</option> option causes each client to dump the package
+version and exit.</para>
+
+<para> The <option>-l</option> option, when present, sets the format
+of latitude and longitude reports.  The value 'd' produces decimal
+degrees and is the default.  The value 'm' produces degrees and
+decimal minutes.  The value 's' produces degrees, minutes, and decimal
+seconds.</para>
+
+<para><application>xgps</application>,
+<application>cgps</application>, and <application>lcdgps</application>
+look at variables in the environment to figure out what units they
+should default to using for display &mdash; imperial, nautical, or
+metric.  Here are the variables and values they check:</para>
+
+<screen>
+    GPSD_UNITS one of:
+              imperial   = miles/feet
+              nautical   = knots/feet
+              metric     = km/meters
+    LC_MEASUREMENT
+	      en_US      = miles/feet
+              C          = miles/feet
+              POSIX      = miles/feet
+              [other]    = km/meters
+    LANG
+	      en_US      = miles/feet
+              C          = miles/feet
+              POSIX      = miles/feet
+              [other]    = km/meters
+</screen>
+<para>These preferences may be overridden by the <option>-u</option>
+option.</para>
+
+<para>Where present, the <option>-u</option> option can be used to set
+the system units for display; follow the keyword with 'i' for
+'imperial' for American units (feet in altitude and error estimates,
+miles per hour in speeds), 'n' for 'nautical' (feet in altitude and
+error estimates, knots in speed) or 'm' for 'metric' (meters in
+altitude and error estimates, kilometers per hour in speeds). </para>
+
+<para> The <option>-D</option> option, when present, sets a debug
+level; it is primarily for use by GPSD developers.  It enables
+various progress messages to standard error.</para>
+
+<para>By default, clients collect data from all compatible devices on
+localhost, using the default GPSD port 2947. An optional argument to any
+client may specify a server to get data from. A colon-separated suffix
+is taken as a port number. If there is a second colon-separated
+suffix, that is taken as a specific device name to be
+watched. However, if the server specification contains square
+brackets, the part inside them is taken as an IPv6 address and
+port/device suffixes are only parsed after the trailing bracket.
+Possible cases look like this:</para>
+
+<variablelist>
+<varlistentry>
+<term>localhost:/dev/ttyS1</term>
+<listitem><para>Look at the default port of localhost, trying both
+IPv4 and IPv6 and watching output from serial device 1.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>example.com:2317</term>
+<listitem><para>Look at port 2317 on example.com, trying both
+IPv4 and IPv6.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>71.162.241.5:2317:/dev/ttyS3</term>
+<listitem><para>Look at port 2317 at the specified IPv4
+address, collecting data from attached serial device 3.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>[FEDC:BA98:7654:3210:FEDC:BA98:7654:3210]:2317:/dev/ttyS5</term>
+<listitem><para>Look at port 2317 at the specified IPv6
+address, collecting data from attached serial device 5.</para></listitem>
+</varlistentry>
+</variablelist>
+
+<para>Not all clients shipped with GPSD are documented here. See also
+the separate manual pages for
+<citerefentry><refentrytitle>gpspipe</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+and
+<citerefentry><refentrytitle>gpsmon</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+and
+<citerefentry><refentrytitle>gpxlogger</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+.</para>
+
+<refsect2><title>xgps</title>
+
+<para><application>xgps</application> is a simple test client for
+<application>gpsd</application> with an X interface. It displays
+current GPS position/time/velocity information and (for GPSes that
+support the feature) the locations of accessible satellites.</para>
+
+<para>In the sky view, satellites are color-coded to indicate quality
+of signal; consult the data display to the left for exact figures in
+dB. Square icons indicate WAAS/EGNOS satellites, circles indicate
+ordinary GPS satellites.  Filled icons were used in the last fix,
+outline icons were not.</para>
+
+</refsect2>
+<refsect2><title>xgpsspeed</title>
+
+<para><application>xgpsspeed</application> is a speedometer that uses
+position information from the GPS. It accepts an -h option and
+optional argument as for <application>gps</application>, or a -V
+option to dump the package version and exit.</para>
+
+<para>The default display mode is a speed and track presentation
+modeled after a marine navigation display; for backward compatibility
+the --nautical option forces this mode. The --landspeed option produces
+a simple speedometer.</para>
+
+<para>The -speedunits option can be used to set the speed units for
+display; follow the keyword with knots for nautical miles per hour,
+kph for kilometres per hour, or mph for miles per hour.  The default
+is miles per hour. </para>
+
+<para>In the nautical mode only, --maxspeed sets the maximum on the
+speedometer.</para>
+
+</refsect2>
+<refsect2><title>cgps</title>
+
+<para><application>cgps</application> is a client resembling
+<application>xgps</application>, but without the pictorial
+satellite display and able to run on a serial terminal or
+terminal emulator.</para>
+
+<para> The <option>-s</option> option prevents
+<application>cgps</application> from displaying the data coming from
+the daemon. This display can also be toggled with the s
+command.</para>
+
+<para>The <option>-m</option> option will display your magnetic
+heading (as opposed to your true heading).  This is a calculated
+value, not a measured value, and is subject to a potential error of up
+to two degrees in the areas for which the calculation is valid
+(currently Western Europe, Alaska, and Lower 48 in the USA).  The
+formulas used are those found in the Aviation Formulary v1.43.</para>
+
+<para><application>cgps</application> terminates when you send it a
+SIGHUP or SIGINT; given default terminal settings this will happen
+when you type Ctrl-C at it.  It will also terminate on 'q'</para>
+
+</refsect2>
+<refsect2><title>lcdgps</title>
+
+<para>A client that passes <application>gpsd</application> data to
+<application>lcdproc</application>, turning your car computer into a
+very expensive and nearly feature-free GPS receiver.  Currently
+assumes a 4x40 LCD and writes data formatted to fit that size screen.
+Also displays 4- or 6-character Maidenhead grid square output.</para>
+
+</refsect2>
+
+<refsect2><title>gegps</title>
+
+<para>This program collects fixes from <application>gpsd</application>
+and feeds them to a running instance of Google Earth for live location
+tracking.</para>
+
+<para>The <option>-d</option> argument is the location of the Google
+Earth installation directory.  If not specified, it defaults to the
+current directory.</para>
+
+<para>If you have the free (non-subscription) version, start by
+running with the <option>-i</option> option to drop a clue in the
+Google Earth installation directory, as
+'Open_in_Google_Earth_RT_GPS.kml', then open that file in Places (File
+> Open...). Run <application>gpsd</application> in the normal way
+after that.</para>
+
+</refsect2>
+</refsect1>
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpscat</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+<citerefentry><refentrytitle>gpspipe</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+<citerefentry><refentrytitle>gpsmon</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+<citerefentry><refentrytitle>gpxlogger</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHORS</title>
+
+<para>
+Remco Treffcorn, Derrick Brashear, Russ Nelson &amp; Eric S. Raymond,
+Jeff Francis (cgps), Chen Wei <email>weichen302@aol.com</email> (gegps &amp; xgpsspeed),
+Robin Wittler <email>real@the-real.org</email> (xgpsspeed).
+</para>
+
+<para>This manual page by Eric S. Raymond <email>esr@thyrsus.com</email></para>
+
+</refsect1>
+
+</refentry>
+
diff --git a/man/gps2udp.xml b/man/gps2udp.xml
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+++ b/man/gps2udp.xml
@@ -0,0 +1,129 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2013 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gps2udp.1'>
+<refentryinfo><date>01 Marc 2013</date></refentryinfo>
+<refmeta>
+<refentrytitle>gps2udp</refentrytitle>
+<manvolnum>1</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gps2udp</refname>
+<refpurpose>feed the take from gpsd to one or more aggregation sites</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gps2udp</command>
+      <arg choice='opt'>-h</arg>
+      <arg choice='opt'>-n</arg>
+      <arg choice='opt'>-j</arg>
+      <arg choice='opt'>-a</arg>
+      <arg choice='opt'>-u <replaceable>hostname:udpport</replaceable></arg>
+      <arg choice='opt'>-c <replaceable>count</replaceable></arg>
+      <arg choice='opt'>-d <replaceable>1|2</replaceable></arg>
+      <arg choice='opt'>-v</arg>
+      <group>
+	<replaceable>server</replaceable>
+	  <group><replaceable>:port</replaceable>
+	    <group><replaceable>:device</replaceable></group>
+	</group>
+      </group>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para><application>gps2udp</application> is a tool to connect to
+<application>gpsd</application> and output the received sentences to
+one or many UDP host:port destinations.  This makes the program useful
+for feeding AIS information from <application>gpsd</application> to
+aishub, marinetraffic, shipfinder,... </para>
+
+<para><application>gps2udp</application> does not require root
+privileges, and can be run concurrently with other tools connecting
+to the local <application>gpsd</application> without causing problems.</para>
+
+<para>The output will consist of one or both of NMEA (-n option) or
+JSON (-j option) <application>gpsd</application> sentences. The
+output is sent to one or many destinations host through a UDP network
+socket (-u host:port options) .</para>
+
+<para>Optionally a server, TCP/IP port number and remote device can be given.
+If omitted, <application>gps2udp</application> connects to localhost on
+the default port (2947) and watches all devices opened by
+<application>gpsd</application>.</para>
+
+<para><application>gps2udp</application> may be run as a daemon (-b
+option).</para>
+
+<para><application>gps2udp</application> is designed to run smoothly in
+background; it reconnects automatically to
+<application>gpsd</application> whenever it is restarted. For
+debugging purporses, there is an option to exit gracefully after a given
+count of packets (-c option).</para>
+
+</refsect1>
+<refsect1 id='options'><title>OPTIONS</title>
+
+<para>-h makes <application>gps2udp</application> print
+a usage message and exit.</para>
+
+<para>-n causes NMEA sentences to be output.</para>
+<para>-j causes JSON sentences to be output.</para>
+<para>-u host:port UDP destination for output sentenses (up to five
+destinations).</para>
+
+<para>-a output only AIS messages.</para>
+<para>-b causes <application>gps2udp</application> to run as a daemon.</para>
+<para>-c [count] causes [count] sentences to be output.
+<application>gps2udp</application> will then exit gracefully.</para>
+
+<para>-d 1 prints sent packet on stdout.</para>
+<para>-v prints the version, then exits.</para>
+</refsect1>
+
+<refsect1 id='exampletitle'><title>EXAMPLE</title>
+<para>With a running <application>gpsd accessible on the
+network</application> </para>
+
+<para><command>gps2udp -d 1 -n -u data.aishub.net:2222 </command> will
+collect data from localhost:gpsd display them on stdout and send a
+copy to test aishub in NMEA format.</para>
+
+<para><command>gps2udp -a -n -b -u data.aishub.net:2222 -u 5.9.207.224:5321 -u 109.200.19.151:4001 fridu.net:2947</command> will collect
+data from a remote gpsd located on fridu.net host, will filter AIS
+messages and send them to 3 destination (aishub, marinetraffic,
+shipfinder) in NMEA format, command is running in background
+mode</para>
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpscat</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+<citerefentry><refentrytitle>gpsmon</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>Fulup Ar Foll <email>fulup@sinagot.net</email>.</para>
+
+</refsect1>
+
+</refentry>
+
diff --git a/man/gpscat.xml b/man/gpscat.xml
new file mode 100644
index 00000000..a22b6a84
--- /dev/null
+++ b/man/gpscat.xml
@@ -0,0 +1,134 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gpscat.1'>
+<refentryinfo><date>16 Nov 2006</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpscat</refentrytitle>
+<manvolnum>1</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpscat</refname>
+<refpurpose>dump the output from a GPS</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gpscat</command>
+      <arg choice='opt'>-s <replaceable>speed</replaceable></arg>
+      <arg choice='opt'>-p</arg>
+      <arg choice='opt'>-t</arg>
+      <arg choice='opt'>-D <replaceable>debuglevel</replaceable></arg>
+      <arg choice='plain'><replaceable>file-or-serial-port</replaceable></arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para><application>gpscat</application> is a simple program for
+logging and packetizing GPS data streams.  It takes input from a
+specified file or serial device (presumed to have a GPS attached) and
+reports to standard output. The program runs until end of input or it is
+interrupted by ^C or other means. It does not terminate on a bad
+backet; this is intentional.</para>
+
+<para>In raw mode (the default) <application>gpscat</application>
+simply dumps its input to standard output.  Nonprintable characters
+other than ASCII whitespace are rendered as hexadecimal string escapes.</para>
+
+<para>In packetizing mode, <application>gpscat</application> uses the
+same code as
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>'s
+packet sniffer to break the input into packets.  Packets are reported
+one per line; line breaks in the packets themselves are
+escaped.</para>
+
+<para>This program is useful as a sanity checker when examining a new
+device.  It can be used as a primitive NMEA logger, but beware that
+(a) interrupting it likely to cut off output in mid-sentence, and (b)
+to avoid displaying incomplete NMEA sentences right up next to shell
+prompts that often contain a $, raw mode always emits an extra final
+linefeed.</para>
+
+<para>Also, be aware that packetizing mode will produce useless
+results &mdash; probably consuming the entirety of input and appearing
+to hang &mdash; if it is fed data that is not a sequence of packets
+of one of the known types.</para>
+
+<para>The program accepts the following options:</para>
+<variablelist remap='TP'>
+
+<varlistentry>
+<term>-p</term>
+<listitem>
+<para>Invoke packetizer mode.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-s</term>
+<listitem>
+<para>Set the port's baud rate (and optionally its parity and stop
+bits) before reading.  Argument should begin with one of the normal integer
+baud rates (300, 1200, 4800, 9600, 19200, 38400, etc.).  It may be
+followed by an optional suffix [NOE][12] to set parity (None, Even,
+Odd) and stop bits (1 or 2).</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-t</term>
+<listitem>
+<para>Invoke packetizer mode, with the packet type and length (in
+parentheses) reported before a colon and space on each line.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-D</term>
+<listitem>
+<para>In packetizer mode, enable progress messages from the packet
+getter.  Probably only of interest to developers testing packet
+getter changes.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-h</term>
+<listitem>
+<para>Display program usage and exit.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+<para>Specifying -s 4800N1 is frequently helpful with unknown
+devices.</para>
+
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsdctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsmon</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>Eric S. Raymond <email>esr@thyrsus.com</email>.</para>
+</refsect1>
+</refentry>
diff --git a/man/gpsctl.xml b/man/gpsctl.xml
new file mode 100644
index 00000000..b0f9f6c0
--- /dev/null
+++ b/man/gpsctl.xml
@@ -0,0 +1,284 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gpsctl.1'>
+<refentryinfo><date>29 Oct 2006</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpsctl</refentrytitle>
+<manvolnum>1</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpsctl</refname>
+<refpurpose>control the modes of a GPS</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gpsctl</command>
+      <arg choice='opt'>-h </arg>
+      <group>
+	<arg choice='plain'>-b</arg>
+	<arg choice='plain'>-n</arg>
+      </group>
+      <arg choice='opt'>-x <replaceable>control</replaceable></arg>
+      <arg choice='opt'>-e </arg>
+      <arg choice='opt'>-f </arg>
+      <arg choice='opt'>-l </arg>
+      <arg choice='opt'>-s <replaceable>speed</replaceable></arg>
+      <arg choice='opt'>-t <replaceable>devicetype</replaceable></arg>
+      <arg choice='opt'>-R </arg>
+      <arg choice='opt'>-D <replaceable>debuglevel</replaceable></arg>
+      <arg choice='opt'>-V </arg>
+      <arg choice='opt'><replaceable>serial-port</replaceable></arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para><application>gpsctl</application> can switch a dual-mode GPS
+between NMEA and vendor-binary modes.  It can also be used to set the
+device baudrate.  Note:  Not all devices have these capabilities.</para>
+
+<para>If you have only one GPS attached to your machine, and gpsd is
+running, it is not necessary to specify the device;
+<application>gpsctl</application> does its work through
+<application>gpsd</application>, which will locate it for you.</para>
+
+<para>When <application>gpsd</application> is not running, the device
+specification is required, and you will need to be running as root or
+be a member of the device's owning group in order to have write access
+to the device. On many Unix variants the owning group will be named
+'dialout'.</para>
+
+<para>The program accepts the following options:</para>
+<variablelist remap='TP'>
+
+<varlistentry>
+<term>-b</term>
+<listitem>
+<para>Put the GPS into native (binary) mode.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-c</term>
+<listitem>
+<para>Change the GPS's cycle time.  Units are seconds.  Note, most
+GPSes have a fixed cycle time of 1 second.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-e</term>
+<listitem>
+<para>Generate the packet from any other arguments specified and ship
+it to standard output instead of the device. This switch can be used
+with the <option>-t</option> option without specifying a device. Note:
+the packet data for a binary prototype will be raw, not ASCII-ized in
+any way.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-f</term>
+<listitem>
+<para>Force low-level access (not through the daemon).</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-l</term>
+<listitem>
+<para>List a table showing which option switches can be applied
+to which device types, and exit.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-n</term>
+<listitem>
+<para>Put GPS into NMEA mode.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-s</term>
+<listitem>
+<para>Set the baud rate at which the GPS emits packets.</para>
+
+<para>Use this option with caution.  On USB and Bluetooth GPSes it is
+also possible for serial mode setting to fail either because the
+serial adaptor chip does not support non-8N1 modes or because the
+device firmware does not properly synchronize the serial adaptor chip
+with the UART on the GPS chipset when the speed changes. These
+failures can hang your device, possibly requiring a GPS power cycle or (in
+extreme cases) physically disconnecting the NVRAM backup battery.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-t</term>
+<listitem>
+<para>Force the device type.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-x</term>
+<listitem>
+<para>Send a specified control string to the GPS;
+<application>gpsctl</application> will provide packet headers and
+trailers and checksum as appropriate for binary packet types, and
+whatever checksum and trailer is required for text packet types.  (You
+must include the leading $ for NMEA packets.) When sending to a UBX
+device, the first two bytes of the string supplied will become the
+message class and type, and the remainder the payload. When sending to
+a Navcom NCT or Trimble TSIP device, the first byte is interpreted as
+the command ID and the rest as payload. When sending to a Zodiac
+device, the first two bytes are used as a message ID of type
+little-endian short, and the remainder as payload in byte pairs
+interpreted as little-endian short. For all other supported binary
+GPSes (notably including SiRF) the string is taken as the entire
+message payload and wrapped with appropriate header, trailer and
+checksum bytes. C-style backslash escapes in the string, notably \xNN
+for hex, will be interpreted; additionally, \e will be replaced with
+ESC. This switch implies <option>-f</option>.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-T</term>
+<listitem>
+<para>Change the sampling timeout. Defaults to 8 seconds, which should
+always be sufficient to get an identifying packet from a device
+emitting at the normal rate of 1 per second.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-R</term>
+<listitem>
+<para>Remove the GPSD shared-memory segment used for SHM export. This
+option will normally only be of interest to GPSD developers.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-h</term>
+<listitem>
+<para>Display program usage and exit.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-D</term>
+<listitem>
+<para>Set level of debug messages.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-V</term>
+<listitem>
+<para>Display program version and exit.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+<para>The argument of the forcing option, <option>-t</option>, should be a
+string which is contained in exactly one of the known driver
+names; for a list, do <command>gpsctl -l</command>.</para>
+
+<para>Forcing the device type behaves somewhat differently depending
+on whether this tool is going through the daemon or not. In high-level
+mode, if the device that daemon selects for you doesn't match the
+driver you specified, <application>gpsctl</application> exits with
+a warning.  (This may be useful in scripts.)</para>
+
+<para>In low-level mode, if the device identifies as a Generic NMEA,
+use the selected driver instead.  This will be useful if you have a
+GPS device of known type that is in NMEA mode and not responding to
+probes.  (This option was originally implemented for talking to
+SiRFStar I chips, which don't respond to the normal SiRF ID
+probe.)</para>
+
+<para>If no options are given, the program will display a message
+identifying the GPS type of the selected device and exit.</para>
+
+<para>Reset (-r) operations must stand alone; others can be combined.
+Multiple options will be executed in this order: mode changes (-b and
+-n) first, speed changes (-s) second, and control-string sends (-c)
+last.</para>
+
+</refsect1>
+
+<refsect1 id='environment'><title>ENVIRONMENT VARIABLES</title>
+
+<para>By setting the environment variable <envar>GPSD_SHM_KEY</envar>,
+you can control the key value used to designate the shared-memory
+segment removed with the -R option.  This will be useful mainly when
+isolating test instances of <application>gpsd</application> from
+production ones.</para>
+
+</refsect1>
+
+<refsect1 id='examples'><title>EXAMPLES</title>
+
+<variablelist>
+<varlistentry>
+<term><command>gpsctl /dev/ttyUSB0</command></term>
+<listitem>
+<para>Attempt to identify the device on USB serial device 0. Time out
+after the default number of seconds. Adding the <option>-f</option> will
+force low-level access and suppress the normal complaint when this
+tool can't find a GPSD to work through.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>gpsctl -f -n -s 9600 /dev/ttyUSB0</term>
+<listitem>
+<para>Use low-level operations (not going through a gpsd instance) to
+switch a GPS to NMEA mode at 9600bps.  The tool will identify the
+GPS type itself.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+</refsect1>
+
+<refsect1 id='bugs'><title>BUGS</title>
+
+<para>SiRF GPSes can only be identified by the success of an attempt
+to flip them into SiRF binary mode. Thus, the process of probing one of
+these running in NMEA will change its behavior.</para>
+
+<para>Baud rate and mode changes work in direct mode but are not
+reliable in client mode.  This will be fixed in a future release.</para>
+
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsdctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>Eric S. Raymond <email>esr@thyrsus.com</email>.</para>
+</refsect1>
+</refentry>
diff --git a/man/gpsd.xml b/man/gpsd.xml
new file mode 100644
index 00000000..49489690
--- /dev/null
+++ b/man/gpsd.xml
@@ -0,0 +1,905 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" [
+<!ENTITY gpsdsock	 "/var/run/gpsd.sock">
+]>
+<refentry id='gpsd.8'>
+<refentryinfo><date>9 Aug 2004</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpsd</refentrytitle>
+<manvolnum>8</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpsd</refname>
+<refpurpose>interface daemon for GPS receivers</refpurpose>
+</refnamediv>
+
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gpsd</command>
+      <arg choice='opt'>-b </arg>
+      <arg choice='opt'>-D <replaceable>debuglevel</replaceable></arg>
+      <arg choice='opt'>-F <replaceable>control-socket</replaceable></arg>
+      <arg choice='opt'>-G </arg>
+      <arg choice='opt'>-h </arg>
+      <arg choice='opt'>-l </arg>
+      <arg choice='opt'>-n </arg>
+      <arg choice='opt'>-N </arg>
+      <arg choice='opt'>-P <replaceable>pidfile</replaceable></arg>
+      <arg choice='opt'>-r </arg>
+      <arg choice='opt'>-S <replaceable>listener-port</replaceable></arg>
+      <arg choice='opt'>-V </arg>
+      <arg rep='repeat'>
+	   <group><replaceable>source-name</replaceable></group>
+      </arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='quickstart'><title>QUICK START</title>
+
+<para>If you have a GPS attached on the lowest-numbered USB port of a
+Linux system, and want to read reports from it on TCP/IP port 2947, it
+will normally suffice to do this:</para>
+
+<programlisting>
+gpsd /dev/ttyUSB0
+</programlisting>
+
+<para>For the lowest-numbered serial port:</para>
+
+<programlisting>
+gpsd /dev/ttyS0
+</programlisting>
+
+<para>Change the device number as appropriate if you need to use a
+different port. Command-line flags enable verbose logging, a control
+port, and other optional extras but should not be needed for basic
+operation; the one exception, on very badly designed hardware, might
+be <option>-b</option> (which see).</para>
+
+<para>On Linux systems supporting udev, <application>gpsd</application>
+is normally started automatically when a USB plugin event fires (if it
+is not already running) and is handed the name of the newly active
+device. In that case no invocation is required at all.</para>
+
+<para>For your initial tests set your GPS hardware to speak NMEA, as
+<application>gpsd</application> is guaranteed to be able to process
+that. If your GPS has a native or binary mode with better performance
+that <application>gpsd</application> knows how to speak,
+<application>gpsd</application> will autoconfigure that mode.</para>
+
+<para>You can verify correct operation by first starting
+<application>gpsd</application> and then
+<application>xgps</application>, the X windows test client.</para>
+
+<para>If you have problems, the GPSD project maintains a FAQ to
+assist troubleshooting.</para>
+
+</refsect1>
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para><application>gpsd</application> is a monitor daemon that collects
+information from GPSes, differential-GPS radios, or AIS receivers
+attached to the host machine.  Each GPS, DGPS radio, or AIS receiver
+is expected to be direct-connected to the host via a USB or RS232C
+serial device.  The serial device may be specified to
+<application>gpsd</application> at startup, or it may be set via a
+command shipped down a local control socket (e.g. by a USB hotplug
+script). Given a GPS device by either means,
+<application>gpsd</application> discovers the correct port speed and
+protocol for it.</para>
+
+<para><application>gpsd</application> should be able to query any GPS
+that speaks either the standard textual NMEA 0183 protocol, or the
+(differing) extended NMEA dialects used by MKT-3301, iTrax, Motorola
+OnCore, Sony CXD2951, and Ashtech/Thales devices.  It can also
+interpret the binary protocols used by EverMore, Garmin, Navcom,
+Rockwell/Zodiac, SiRF, Trimble, and u-blox ANTARIS devices. Under Linux
+it can read NMEA2000 packets through the kernel CAN socket. It can read
+heading and attitude information from the Oceanserver 5000 or TNT
+Revolution digital compasses.</para>
+
+<para>The GPS reporting formats supported by your instance of
+<application>gpsd</application> may differ depending on how it was
+compiled; general-purpose versions support many, but it can be built
+with protocol subsets down to a singleton for use in constrained
+environments. For a list of the GPS protocols supported by your
+instance, see the output of <command>gpsd -l</command></para>
+
+<para><application>gpsd</application> effectively hides the
+differences among the GPS types it supports. It also knows about and
+uses commands that tune these GPSes for lower latency. By using
+<application>gpsd</application> as an intermediary, applications
+avoid contention for serial devices.</para>
+
+<para><application>gpsd</application> can use differential-GPS
+corrections from a DGPS radio or over the net, from a ground station
+running a DGPSIP server or a Ntrip broadcaster that reports RTCM-104
+data; this will shrink position errors by roughly a factor of four.
+When <application>gpsd</application> opens a serial device emitting
+RTCM-104, it automatically recognizes this and uses the device as a
+correction source for all connected GPSes that accept RTCM corrections
+(this is dependent on the type of the GPS; not all GPSes have the
+firmware capability to accept RTCM correction packets). See
+<xref linkend='accuracy'/> and <xref linkend='files'/> for discussion.</para>
+
+<para>Client applications will communicate with <application>gpsd</application>
+via a TCP/IP port, 2947 by default).  Both IPv4 and IPv6 connections
+are supported and a client may connect via either.</para>
+
+<para>The program accepts the following options:</para>
+<variablelist remap='TP'>
+<varlistentry>
+<term>-b</term>
+<listitem><para>Broken-device-safety mode, otherwise known as
+read-only mode. A few bluetooth and USB receivers lock up or become
+totally inaccessible when probed or reconfigured; see the hardware
+compatibility list on the GPSD project website for details. This
+switch prevents gpsd from writing to a receiver.  This means that
+<application>gpsd</application> cannot configure the receiver for
+optimal performance, but it also means that
+<application>gpsd</application> cannot break the receiver. A better
+solution would be for Bluetooth to not be so fragile. A platform
+independent method to identify serial-over-Bluetooth devices would
+also be nice.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>-D</term>
+<listitem>
+<para>Set debug level. At debug levels 2 and above,
+<application>gpsd</application> reports incoming sentence and actions
+to standard error if <application>gpsd</application> is in the foreground
+(-N) or to syslog if in the background.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>-F</term>
+<listitem>
+<para>Create a control socket for device addition and removal
+commands.  You must specify a valid pathname on your local filesystem;
+this will be created as a Unix-domain socket to which you can write
+commands that edit the daemon's internal device list.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>-G</term>
+<listitem><para>This flag causes <application>gpsd</application> to
+listen on all addresses (INADDR_ANY) rather than just the loop back
+(INADDR_LOOPBACK) address. For the sake of privacy and security, TPV
+information is now private to the local machine until the user makes
+an effort to expose this to the world.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>-h</term>
+<listitem><para>Display help message and terminate.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>-l</term>
+<listitem><para>List all drivers compiled into this
+<application>gpsd</application> instance. The letters to the left of
+each driver name are the <application>gpsd</application>
+control commands supported by that driver.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>-n</term>
+<listitem>
+<para>Don't wait for a client to connect before polling whatever GPS
+is associated with it. Some RS232 GPSes wait in a standby mode
+(drawing less power) when the host machine is not asserting DTR, and
+some cellphone and handheld embedded GPSes have similar behaviors.
+Accordingly, waiting for a watch request to open the device may save
+battery power. (This capability is rare in consumer-grade devices).
+</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>-N</term>
+<listitem><para>Don't daemonize; run in foreground.
+This switch is mainly useful for debugging.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>-r</term>
+<listitem><para>Use GPS time even with no current fix.  Some GPS's have
+battery powered Real Time Clocks (RTC's) built in, makeing them a valid time
+source even before a fix is acquired.  This can be useful on a Raspberry Pi,
+or other device that has no battery powered RTC, and thus has no valid
+time at startup.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>-P</term>
+<listitem>
+<para>Specify the name and path to record the daemon's process ID.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>-S</term>
+<listitem><para>Set TCP/IP port on which to listen for GPSD clients
+(default is 2947).</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>-V</term>
+<listitem>
+<para>Dump version and exit.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+<para>Arguments are interpreted as the names of data sources.
+Normally, a data source is the device pathname of a local device from
+which the daemon may expect GPS data. But there are three other
+special source types recognized, for a total of four:</para>
+
+<variablelist>
+<varlistentry>
+<term>Local serial or USB device</term>
+<listitem>
+<para>A normal Unix device name of a serial or USB device to which a
+sensor is attached. Example:
+<filename>/dev/ttyUSB0</filename>.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>Local PPS device</term>
+<listitem>
+<para>A normal Unix device name of a PPS device to which a PPS source
+is attached.  The device name must start with "/dev/pps" and a local
+serial or USB GPS device must also be available. Example:
+<filename>/dev/pps0</filename>.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>TCP feed</term>
+<listitem>
+<para>A URI with the prefix "tcp://", followed by a hostname, a
+colon, and a port number. The daemon will open a socket to the
+indicated address and port and read data packets from it, which will
+be interpreted as though they had been issued by a serial device. Example:
+<filename>tcp://data.aishub.net:4006</filename>.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>UDP feed</term>
+<listitem>
+<para>A URI with the prefix "udp://", followed by a hostname, a
+colon, and a port number. The daemon will open a socket listening for
+UDP datagrams arriving on the indicated address and port, which will
+be interpreted as though they had been issued by a serial device. Example:
+<filename>udp://127.0.0.1:5000</filename>.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>Ntrip caster</term>
+<listitem>
+<para>A URI with the prefix "ntrip://" followed by the name of an
+Ntrip caster (Ntrip is a protocol for broadcasting differential-GPS
+fixes over the net). For Ntrip services that require authentication, a
+prefix of the form "username:password@" can be added before the name
+of the Ntrip broadcaster.  For Ntrip service, you must specify which
+stream to use; the stream is given in the form "/streamname". An
+example DGPSIP URI could be "dgpsip://dgpsip.example.com" and a Ntrip
+URI could be
+"ntrip://foo:bar@ntrip.example.com:80/example-stream". Corrections
+from the caster will be send to each attached GPS with the capability
+to accept them.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>DGPSIP server</term>
+<listitem>
+<para>A URI with the prefix "dgpsip://" followed by a hostname, a
+colon, and an optional colon-separated port number (defaulting to
+2101). The daemon will handshake with the DGPSIP server and
+read RTCM2 correction data from it. Corrections
+from the server will be set to each attached GPS with the capability
+to accept them. Example:
+<filename>dgpsip://dgps.wsrcc.com:2101</filename>.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>Remote gpsd feed</term>
+<listitem>
+<para>A URI with the prefix "gpsd://", followed by a hostname and
+optionally a colony and a port number (if the port is absent the
+default <application>gpsd</application> port will be used). The daemon
+will open a socket to the indicated address and port and emulate a
+<application>gpsd</application> client, collecting JSON reports from
+the remote <application>gpsd</application> instance that will be
+passed to local clients.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>NMEA2000 CAN data</term>
+<listitem>
+<para>A URI with the prefix "nmea2000://", followed by a CAN
+devicename. Only Linux socket CAN interfaces are supported. The
+interface must be configured to receive CAN messages
+before <application>gpsd</application> can be started. If
+there is more then one unit on the CAN bus that provides GPS data,
+<application>gpsd</application> chooses the unit from which a GPS message
+is first seen. Example: <filename>nmea2000://can0</filename>.
+</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+<para>(The "ais:://" source type supported in some older versions of
+the daemon has been retired in favor of the more general
+"tcp://".)</para>
+
+<para>Additionally, two serial device names have a side effect:
+<variablelist>
+<varlistentry>
+<term>/dev/ttyAMA0</term>
+<listitem>
+<para>The UART device on a Raspberry Pi. Has the side effect of
+opening /dev/pps0 for RFC2783 1PPS data.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>Generic GPS device 0. Has the side effect of
+opening /dev/pps0 for RFC2783 1PPS data/</term>
+<listitem>
+<para> </para>
+</listitem>
+</varlistentry>
+</variablelist>
+</para>
+
+<para>Internally, the daemon maintains a device pool holding the
+pathnames of devices and remote servers known to the
+daemon. Initially, this list is the list of device-name arguments
+specified on the command line.  That list may be empty, in which case
+the daemon will have no devices on its search list until they are
+added by a control-socket command (see <xref linkend='devices'/> for
+details on this).  Daemon startup will abort with an error if neither
+any devices nor a control socket are specified.</para>
+
+<para>When a device is activated (i.e. a client requests data from it),
+gpsd attempts to execute a hook from
+<filename>/etc/gpsd/device-hook</filename> with first command line argument
+set to the pathname of the device and the second to
+<option>ACTIVATE</option>. On deactivation it does the same passing
+<option>DEACTIVATE</option> for the second argument.</para>
+
+<para><application>gpsd</application> can export data to client applications
+in three ways: via a sockets interface, via a shared-memory segment, and
+via D-Bus. The next three major sections describe these interfaces.</para>
+
+</refsect1>
+<refsect1 id='sockets'><title>THE SOCKET INTERFACE</title>
+
+<para>Clients may communicate with the daemon via textual request and
+responses over a socket. It is a bad idea for applications to speak the protocol
+directly: rather, they should use the
+<application>libgps</application> client library and take appropriate
+care to conditionalize their code on the major and minor protocol
+version symbols.</para>
+
+<para>The request-response protocol for the socket interface is fully
+documented in
+<citerefentry><refentrytitle>gpsd_json</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+
+</refsect1>
+
+<refsect1 id='shm'><title>SHARED-MEMORY AND DBUS INTERFACES</title>
+
+<para><application>gpsd</application> has two other (read-only)
+interfaces.</para>
+
+<para>Whenever the daemon recognizes a packet from any attached
+device, it writes the accumulated state from that device to a shared
+memory segment.  The C and C++ client libraries shipped with GPSD can
+read this segment. Client methods, and various restrictions associated
+with the read-only nature of this interface, are documented at
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>. The
+shared-memory interface is intended primarily for embedded deployments
+in which <application>gpsd</application> monitors a single device, and
+its principal advantage is that a daemon instance configured with
+shared memory but without the sockets interface loses a significant
+amount of runtime weight.</para>
+
+<para>The daemon may be configured to emit a D-Bus signal each time an
+attached device delivers a fix.  The signal path is <filename>path
+/org/gpsd</filename>, the signal interface is "org.gpsd", and the
+signal name is "fix".  The signal payload layout is as follows:</para>
+
+<table frame="all" pgwide="0"><title>Satellite object</title>
+<tgroup cols="2" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Time (seconds since Unix epoch)</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_INT32</entry>
+        <entry><para>mode</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Time uncertainty (seconds).</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Latitude in degrees.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Longitude in degrees.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Horizontal uncertainty in meters, 95% confidence.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Altitude in meters.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Altitude uncertainty in meters, 95% confidence.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Course in degrees from true north.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Course uncertainty in meters, 95% confidence.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Speed, meters per second.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Speed uncertainty in meters per second,
+	95% confidence.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Climb, meters per second.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_DOUBLE</entry>
+        <entry><para>Climb uncertainty in meters per second,
+	95% confidence.</para></entry>
+</row>
+<row>
+	<entry>DBUS_TYPE_STRING</entry>
+        <entry><para>Device name</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+</refsect1>
+
+<refsect1 id='devices'><title>GPS DEVICE MANAGEMENT</title>
+
+<para><application>gpsd</application> maintains an internal list of
+GPS devices (the "device pool").  If you specify devices on the
+command line, the list is initialized with those pathnames; otherwise
+the list starts empty.  Commands to add and remove GPS device paths
+from the daemon's device list must be written to a local Unix-domain
+socket which will be accessible only to programs running as root.
+This control socket will be located wherever the -F option specifies
+it.</para>
+
+<para>A device may will also be dropped from the pool if GPSD gets a zero
+length read from it. This  end-of-file condition indicates that the'
+device has been disconnected.</para>
+
+<para>When <application>gpsd</application> is properly installed along
+with hotplug notifier scripts feeding it device-add commands over the
+control socket, <application>gpsd</application> should require no
+configuration or user action to find devices.</para>
+
+<para>Sending SIGHUP to a running <application>gpsd</application>
+forces it to close all GPSes and all client connections.  It will then
+attempt to reconnect to any GPSes on its device list and resume
+listening for client connections.  This may be useful if your GPS
+enters a wedged or confused state but can be soft-reset by pulling
+down DTR.</para>
+
+<para>When <application>gpsd</application> is called with no initial
+devices (thus, expecting devices to be passed to it by notifications to
+the control socket), and reaches a state where there are no devices
+connected and no subscribers <emphasis>after</emphasis> after some
+devices have been seen, it shuts down gracefully. It is expected that
+future device hotplug events will reactivate it.</para>
+
+<para>To point <application>gpsd</application> at a device that may be
+a GPS, write to the control socket a plus sign ('+') followed by the
+device name followed by LF or CR-LF.  Thus, to point the daemon at
+<filename>/dev/foo</filename>. send "+/dev/foo\n".  To tell the daemon
+that a device has been disconnected and is no longer available, send a
+minus sign ('-') followed by the device name followed by LF or
+CR-LF. Thus, to remove <filename>/dev/foo</filename> from the search
+list, send "-/dev/foo\n".</para>
+
+<para>To send a control string to a specified device, write to the
+control socket a '!', followed by the device name, followed by '=',
+followed by the control string.</para>
+
+<para>To send a binary control string to a specified device, write to the
+control socket a '&amp;', followed by the device name, followed by '=',
+followed by the control string in paired hex digits.</para>
+
+<para>Your client may await a response, which will be a line beginning
+with either "OK" or "ERROR".  An ERROR response to an add command means
+the device did not emit data recognizable as GPS packets; an ERROR
+response to a remove command means the specified device was not in
+<application>gpsd</application>'s device pool. An ERROR response to a
+! command means the daemon did not recognize the devicename
+specified.</para>
+
+<para>The control socket is intended for use by hotplug scripts and
+other device-discovery services.  This control channel is separate
+from the public <application>gpsd</application> service port, and only
+locally accessible, in order to prevent remote denial-of-service and
+spoofing attacks.</para>
+
+</refsect1>
+<refsect1 id='accuracy'><title>ACCURACY</title>
+
+<para>The base User Estimated Range Error (UERE) of GPSes is 8 meters
+or less at 66% confidence, 15 meters or less at 95% confidence. Actual
+horizontal error will be UERE times a dilution factor dependent on current
+satellite position.  Altitude determination is more sensitive to
+variability in ionospheric signal lag than latitude/longitude is, and is
+also subject to errors in the estimation of local mean sea level; base
+error is 12 meters at 66% confidence, 23 meters at 95% confidence.
+Again, this will be multiplied by a vertical dilution of precision
+(VDOP) dependent on satellite geometry, and VDOP is typically larger
+than HDOP.  Users should <emphasis>not</emphasis> rely on GPS altitude for
+life-critical tasks such as landing an airplane.</para>
+
+<para>These errors are intrinsic to the design and physics of the GPS
+system.  <application>gpsd</application> does its internal
+computations at sufficient accuracy that it will add no measurable
+position error of its own.</para>
+
+<para>DGPS correction will reduce UERE by a factor of 4, provided you
+are within about 100mi (160km) of a DGPS ground station from which you
+are receiving corrections.</para>
+
+<para>On a 4800bps connection, the time latency of fixes provided by
+<application>gpsd</application> will be one second or less 95% of the
+time.  Most of this lag is due to the fact that GPSes normally emit
+fixes once per second, thus expected latency is 0.5sec.  On the
+personal-computer hardware available in 2005 and later, computation
+lag induced by <application>gpsd</application> will be negligible, on
+the order of a millisecond.  Nevertheless, latency can introduce
+significant errors for vehicles in motion; at 50km/h (31mi/h) of speed
+over ground, 1 second of lag corresponds to 13.8 meters change in
+position between updates.</para>
+
+<para>The time reporting of the GPS system itself has an intrinsic
+accuracy limit of 14 nanoseconds, but this can only be approximated by
+specialized receivers using that send the high-accuracy PPS
+(Pulse-Per-Second) over RS232 to cue a clock crystal.  Most GPS
+receivers only report time to a precision of 0.01s or 0.001s,
+and with no accuracy guarantees below 1sec.</para>
+
+<para>If your GPS uses a SiRF chipset at firmware level 231, reported
+UTC time may be off by the difference between whatever default
+leap-second offset has been compiled in and whatever leap-second
+correction is currently applicable, from startup until complete
+subframe information is received.  Firmware levels 232 and up don't
+have this problem.  You may run <application>gpsd</application> at
+debug level 4 to see the chipset type and firmware revision
+level.</para>
+
+<para>There are exactly two circumstances under which
+<application>gpsd</application> relies on the host-system
+clock:</para>
+
+<para>In the GPS broadcast signal, GPS time is represented using a
+week number that rolls over after 2^10 or 2^13 weeks (about 19.6
+years, or 157 years), depending on the spacecraft.  Receivers are
+required to disambiguate this to the correct date, but may have
+difficulty due to not knowing time to within half this interval, or
+may have bugs.  Users have reported incorrect dates which appear to be
+due to this issue.  <application>gpsd</application> uses the startup
+time of the daemon detect and compensate for rollovers while it is
+running, but otherwise reports the date as it is reported by the
+receiver without attempting to correct it.</para>
+
+<para>If you are using an NMEA-only GPS (that is, not using SiRF or
+Garmin or Zodiac binary mode), <application>gpsd</application> relies
+on the system clock to tell it the current century. If the system clock
+returns an invalid value near zero, and the GPS does not emit GPZDA at
+the start of its update cycle (which most consumer-grade NMEA GPSes do
+not) then the century part of the dates
+<application>gpsd</application> delivers may be wrong. Additionally,
+near the century turnover, a range of dates as wide in seconds as the
+accuracy of your system clock may be referred to the wrong
+century.</para>
+</refsect1>
+
+<refsect1 id='ntp'><title>USE WITH NTP</title>
+
+<para>gpsd can provide reference clock information to
+<application>ntpd</application>, to keep the system clock synchronized
+to the time provided by the GPS receiver.</para>
+
+<para>On Linux, <application>gpsd</application> includes support for
+interpreting the PPS pulses emitted at the start of every clock second
+on the carrier-detect lines of some serial GPSes; this pulse can be
+used to update NTP at much higher accuracy than message time provides.
+You can determine whether your GPS emits this pulse by running at -D 5
+and watching for carrier-detect state change messages in the logfile.
+In addition, if your kernel provides the RFC 2783 kernel PPS API then
+<application>gpsd</application> will use that for extra
+accuracy.</para>
+
+<para>Detailed instructions for using GPSD to set up a high-quality
+time service can be found among the documentation on the GPSD
+website.</para>
+</refsect1>
+
+<refsect1 id='dbus'><title>USE WITH D-BUS</title>
+
+<para>On operating systems that support D-BUS,
+<application>gpsd</application> can be built to broadcast GPS fixes to
+D-BUS-aware applications.  As D-BUS is still at a pre-1.0 stage, we
+will not attempt to document this interface here.  Read the
+<application>gpsd</application> source code to learn more.</para>
+
+</refsect1>
+<refsect1 id='security'><title>SECURITY AND PERMISSIONS ISSUES</title>
+
+<para><application>gpsd</application>, if given the -G flag, will
+listen for connections from any reachable host, and then disclose the
+current position.  Before using the -G flag, consider whether you
+consider your computer's location to be sensitive data to be kept
+private or something that you wish to publish.</para>
+
+<para><application>gpsd</application> must start up as root in order
+to open the NTPD shared-memory segment, open its logfile, and create
+its local control socket.  Before doing any processing of GPS data, it
+tries to drop root privileges by setting its UID to "nobody" (or another
+configured userid) and its group ID to the group of the initial
+GPS passed on the command line &mdash; or, if that device doesn't exist,
+to the group of <filename>/dev/ttyS0</filename>.</para>
+
+<para>Privilege-dropping is a hedge against the possibility that
+carefully crafted data, either presented from a client socket or from
+a subverted serial device posing as a GPS, could be used to induce
+misbehavior in the internals of <application>gpsd</application>.
+It ensures that any such compromises cannot be used for privilege
+elevation to root.</para>
+
+<para>The assumption behind <application>gpsd</application>'s
+particular behavior is that all the tty devices to which a GPS might
+be connected are owned by the same non-root group and allow group
+read/write, though the group may vary because of distribution-specific
+or local administrative practice.  If this assumption is false,
+<application>gpsd</application> may not be able to open GPS devices in
+order to read them (such failures will be logged).</para>
+
+<para>In order to fend off inadvertent denial-of-service attacks by
+port scanners (not to mention deliberate ones),
+<application>gpsd</application> will time out inactive client
+connections.  Before the client has issued a command that requests a
+channel assignment, a short timeout (60 seconds) applies.  There is no
+timeout for clients in watcher or raw modes; rather,
+<application>gpsd</application> drops these clients if they fail to
+read data long enough for the outbound socket write buffer to fill.
+Clients with an assigned device in polling mode are subject to a
+longer timeout (15 minutes).</para>
+
+</refsect1>
+<refsect1 id='limitations'><title>LIMITATIONS</title>
+
+<para>If multiple NMEA talkers are feeding RMC, GLL, and GGA sentences
+to the same serial device (possible with an RS422 adapter hooked up to
+some marine-navigation systems), a 'TPV' response may mix an altitude
+from one device's GGA with latitude/longitude from another's RMC/GLL
+after the second sentence has arrived.</para>
+
+<para><application>gpsd</application> may change control settings on
+your GPS (such as the emission frequency of various sentences or
+packets) and not restore the original settings on exit.  This is a
+result of inadequacies in NMEA and the vendor binary GPS protocols,
+which often do not give clients any way to query the values of control
+settings in order to be able to restore them later.</para>
+
+<para>When using SiRF chips, the VDOP/TDOP/GDOP figures and associated
+error estimates are computed by <application>gpsd</application> rather
+than reported by the chip.  The computation does not exactly match
+what SiRF chips do internally, which includes some satellite weighting
+using parameters <application>gpsd</application> cannot see.</para>
+
+<para>Autobauding on the Trimble GPSes can take as long as 5 seconds
+if the device speed is not matched to the GPS speed.</para>
+
+<para>Generation of position error estimates (eph, epv, epd, eps, epc)
+from the incomplete data handed back by GPS reporting protocols
+involves both a lot of mathematical black art and fragile
+device-dependent assumptions.  This code has been bug-prone in tbe
+past and problems may still lurk there.</para>
+
+<para>AIDVM decoding of types 16-17, 22-23, and 25-26 is unverified.</para>
+
+<para>GPSD presently fully recognizes only the 2.1 level of RTCM2
+(message types 1, 3, 4, 5, 6, 7, 9, 16). The 2.3 message types 13, 14,
+and 31 are recognized and reported. Message types 8, 10-12, 15-27,
+28-30 (undefined), 31-37, 38-58 (undefined), and 60-63 are not yet
+supported.</para>
+
+<para>The ISGPS used for RTCM2 and subframes decoder logic is
+sufficiently convoluted to confuse some compiler optimizers, notably
+in GCC 3.x at -O2, into generating bad code.</para>
+
+<para>Devices meant to use PPS for high-precision timekeeping may
+fail if they are specified after startup by a control-socket command,
+as opposed to on the daemon's original command line. Root privileges
+are dropped early, and some Unix variants require them in order to set
+the PPS line discipline. Under Linux the POSIX capability to set the
+line discipline is retained, but other platforms cannot use this
+code.</para>
+
+<para>USB GPS devices often do not identify themselves through the USB
+subsystem; they typically present as the class 00h (undefined) or
+class FFh (vendor-specific) of USB-to-serial adapters. Because of
+this, the Linux hotplug scripts must tell
+<application>gpsd</application> to sniff data from every USB-to-serial
+adapter that goes active and is known to be of a type used in
+GPSes. No such device is sent configuration strings until after it has
+been identified as a GPS, and <application>gpsd</application> never
+opens a device that is opened by another process.  But there is a tiny
+window for non-GPS devices not opened; if the application that wants
+them loses a race with GPSD its device open will fail and have to be
+retried after GPSD sniffs the device (normally less than a second
+later).</para>
+
+</refsect1>
+<refsect1 id='files'><title>FILES</title>
+
+<variablelist>
+<varlistentry>
+<term><filename>/dev/ttyS0</filename></term>
+<listitem>
+<para>Prototype TTY device. After startup,
+<application>gpsd</application> sets its group ID to the owning group of this
+device if no GPS device was specified on the command line does not
+exist.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term><filename>/etc/gpsd/device-hook</filename></term>
+<listitem>
+<para>Optional file containing the device activation/deactivation script.
+Note that while <filename>/etc/gpsd</filename> is the default system
+configuration directory, it is possible to build the GPSD source code
+with different assumptions.</para>
+</listitem>
+</varlistentry>
+<!--
+<varlistentry>
+<term><filename>/usr/share/gpsd/dgpsip-servers</filename></term>
+<listitem>
+<para>A text file listing DGPSIP servers worldwide.  If no DGPSIP
+server is specified at startup (via the -d option)
+<application>gpsd</application> will look here to find the
+nearest one.  Each line has three space-separated fields:
+latitude (decimal degrees), longitude (decimal degrees) and
+a server name (optionally followed by a colon and a port number).
+Text following # on a line is ignored.  Blank lines are ignored.</para>
+</listitem>
+</varlistentry>
+-->
+</variablelist>
+
+</refsect1>
+<refsect1 id='environment'><title>ENVIRONMENT VARIABLES</title>
+
+<para>By setting the environment variable <envar>GPSD_SHM_KEY</envar>,
+you can control the key value used to create the shared-memory segment
+used for communication with the client library.  This will be useful
+mainly when isolating test instances of
+<application>gpsd</application> from production ones.</para>
+
+</refsect1>
+<refsect1 id='standards'><title>APPLICABLE STANDARDS</title>
+
+<para>The official NMEA protocol standards for NMEA0183 and NMEA2000
+are available from the National Marine Electronics Association, but are
+proprietary and expensive; the maintainers of
+<application>gpsd</application> have made a point of not looking at
+them.  The GPSD project website links to several documents that collect
+publicly disclosed information about the protocol.</para>
+
+<para><application>gpsd</application> parses the following NMEA
+sentences: RMC, GGA, GLL, GSA, GSV, VTG, ZDA, GBS, HDT, DBT, GST.  It
+recognizes these with either the normal GP talker-ID prefix, or with
+the GN prefix used by GLONASS, or with the II prefix emitted by
+Seahawk Autohelm marine navigation systems, or with the IN prefix
+emitted by some Garmin units, or with the EC prefix emitted by ECDIS
+units, or with the SD prefix emitted by depth sounders, or with the HC
+and TI prefix emitted by some Airmar equipment.  It recognizes some
+vendor extensions: the PGRME emitted by some Garmin GPS models, the
+OHPR emitted by Oceanserver digital compasses, the PTNTHTM emitted by
+True North digital compasses, the PMTK omitted by some San Jose
+Navigation GPSes, and the PASHR sentences emitted by some Ashtech
+GPSes.</para>
+
+<para>Note that <application>gpsd</application> JSON returns pure decimal
+degrees, not the hybrid degree/minute format described in the NMEA
+standard.</para>
+
+<para>Differential-GPS corrections are conveyed by the RTCM
+protocols. The applicable standard for RTCM-104 V2 is <citetitle>RTCM
+Recommended Standards for Differential GNSS (Global Navigation
+Satellite) Service</citetitle> RTCM Paper 136-2001/SC 104-STD.  The
+applicable standard for RTCM-104 V3 is <citetitle>RTCM Standard
+10403.1 for Differential GNSS Services - Version 3</citetitle> RTCM
+Paper 177-2006-SC104-STD. Ordering instructions for the RTCM standards
+are accessible from the website of the Radio Technical Commission for Maritime
+Services under "Publications".</para>
+
+<para>AIS is defined by ITU Recommendation M.1371,
+<citetitle>Technical Characteristics for a Universal Shipborne
+Automatic Identification System Using Time Division Multiple
+Access</citetitle>. The AIVDM/AIVDO format understood by this program
+is defined by IEC-PAS 61162-100, <citetitle>Maritime navigation and
+radiocommunication equipment and systems</citetitle>. A more accessible
+description of both can be found at <citetitle>AIVDM/AIVDO Protocol
+Decoding</citetitle>, on the references page of the GPSD project
+website.</para>
+
+<para>Subframe data is defined by IS-GPS-200E, <citetitle>GLOBAL
+POSITIONING SYSTEM WING (GPSW) SYSTEMS ENGINEERING &amp; INTEGRATION,
+INTERFACE SPECIFICATION IS-GPS-200 Revision E</citetitle>. The format
+understood by this program is defined in Section 20 (Appendix II) of
+the IS-GPS-200E, <citetitle>GPS NAVIGATION DATA STRUCTURE FOR DATA,
+D(t)</citetitle></para>
+
+<para>JSON is specified by RFC 7159, <citetitle>The JavaScript Object
+Notation (JSON) Data Interchange Format</citetitle>.</para>
+
+<para>The API for PPS time service is specified by RFC 2783,
+<citetitle>Pulse-Per-Second API for UNIX-like Operating Systems,
+Version 1.0</citetitle></para>
+
+</refsect1>
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsdctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsd_json</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpscat</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHORS</title>
+
+<para>Authors: Eric S. Raymond, Chris Kuethe, Gary Miller.  Former
+authors whose bits have been plowed under by code turnover: Remco
+Treffcorn, Derrick Brashear, Russ Nelson. This manual page by Eric S. Raymond
+<email>esr@thyrsus.com</email>.</para>
+</refsect1>
+
+</refentry>
diff --git a/man/gpsd_json.xml b/man/gpsd_json.xml
new file mode 100644
index 00000000..1c868b61
--- /dev/null
+++ b/man/gpsd_json.xml
@@ -0,0 +1,2609 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010-2018 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" [
+<!ENTITY gpsdsock	 "/var/run/gpsd.sock">
+]>
+<refentry id='gpsd_json.5'>
+<refentryinfo><date>17 Jun 2018</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpsd_json</refentrytitle>
+<manvolnum>5</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpsd_json</refname>
+<refpurpose>gpsd request/response protocol</refpurpose>
+</refnamediv>
+
+<refsect1 id='overview'><title>OVERVIEW</title>
+
+<para><application>gpsd</application> is a service daemon that can be used
+to monitor GPSes, DGPS receivers, Marine AIS broadcasts, and various other
+location-related and kinematic sensors.</para>
+
+<para>Clients may communicate with <application>gpsd</application> via
+textual requests and responses over a socket. It is a bad idea for
+applications to speak the protocol directly: rather, they should use
+the <application>libgps</application> client library (for C; bindings
+also exist for other languages) and take appropriate care to
+conditionalize their code on the major and minor protocol version
+symbols.</para>
+
+<para>The GPSD protocol is built on top of JSON, JavaScript Object
+Notation, as specified in RFC 7159: <citetitle>The JavaScript Object
+Notation (JSON) Data Interchange Format</citetitle>. GPSD's use of
+JSON is restricted in some ways that make parsing it in fixed-extent
+languages (such as C) easier.</para>
+
+<para>A request line is introduced by "?" and may include multiple
+commands.  Commands begin with a command identifier, followed either
+by a terminating ';' or by an equal sign "=" and a JSON object treated
+as an argument.  Any ';' or newline indication (either LF or CR-LF)
+after the end of a command is ignored. All request lines must be
+composed of US-ASCII characters and may be no more than 80 characters
+in length, exclusive of the trailing newline.</para>
+
+<para>Responses are JSON objects all of which have a "class" attribute
+the value of which is either the name of the invoking command.  There
+are reports (including but not limited to as "TPV", "SKY", "DEVICE",
+and "ERROR") which are not direct responses to commands.</para>
+
+<para> The order of JSON attributes within a response object is never
+significant, and you may specify attributes in commands in any
+order. Responses never contain the special JSON value null; instead,
+attributes with empty or undefined values are omitted. The length
+limit for responses and reports is 1536 characters, including trailing
+newline; longer responses will be truncated, so client code must be
+prepared for the possibility of invalid JSON fragments.</para>
+
+<para>In JSON reports, if an attribute is present only if the parent
+attribute is present or has a particular range, then the parent
+attribute is emitted first.</para>
+
+<para>There is one constraint on the order in which attributes will
+be omitted. If an optional attribute is present only when a parent
+attribute has a specified value or range of values, the parent
+attribute will be emitted first to make parsing easier.</para>
+
+<para>The next subsection section documents the core GPSD protocol.
+Extensions are documented in the following subsections. The extensions
+may not be supported in your <application>gpsd</application> instance
+if it has been compiled with a restricted feature set.</para>
+
+</refsect1>
+<refsect1 id='core-protocol'><title>CORE SOCKET PROTOCOL</title>
+
+<para>Here are the core-protocol responses:</para>
+
+<variablelist>
+<varlistentry>
+<term>TPV</term>
+<listitem>
+<para>A TPV object is a time-position-velocity report. The "class" and "mode"
+fields will reliably be present. The "mode" field will be emitted
+before optional fields that may be absent when there is no fix. Error
+estimates will be emitted after the fix components they're associated with.
+Others may be reported or not depending on the fix quality.</para>
+
+<table frame="all" pgwide="0"><title>TPV object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "TPV"</entry>
+</row>
+<row>
+	<entry>device</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Name of originating device.</entry>
+</row>
+<row>
+	<entry>status</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>GPS status: %d, 2=DGPS fix, otherwise not present.</entry>
+</row>
+<row>
+	<entry>mode</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>NMEA mode: %d, 0=no mode value yet seen, 1=no fix, 2=2D, 3=3D.</entry>
+</row>
+<row>
+	<entry>time</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Time/date stamp in ISO8601 format, UTC. May have a
+	fractional part of up to .001sec precision. May be absent if mode
+        is not 2 or 3.</entry>
+</row>
+<row>
+	<entry>ept</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Estimated timestamp error (%f, seconds, 95% confidence).
+        Present if time is present.</entry>
+</row>
+<row>
+	<entry>lat</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Latitude in degrees: +/- signifies North/South.  Present
+        when mode is 2 or 3.</entry>
+</row>
+<row>
+	<entry>lon</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Longitude in degrees: +/- signifies East/West. Present
+        when mode is 2 or 3.</entry>
+</row>
+<row>
+	<entry>alt</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Altitude in meters. Present if mode is 3.</entry>
+</row>
+<row>
+	<entry>epx</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Longitude error estimate in meters, 95% confidence. Present
+        if mode is 2 or 3 and DOPs can be calculated from the satellite
+        view.</entry>
+</row>
+<row>
+	<entry>epy</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Latitude error estimate in meters, 95% confidence. Present
+        if mode is 2 or 3 and DOPs can be calculated from the satellite
+        view.</entry>
+</row>
+<row>
+	<entry>epv</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Estimated vertical error in meters, 95% confidence. Present
+        if mode is 3 and DOPs can be calculated from the satellite
+        view.</entry>
+</row>
+<row>
+	<entry>track</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Course over ground, degrees from true north.</entry>
+</row>
+<row>
+	<entry>magtrack</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Course over ground, degrees magnetic.</entry>
+</row>
+<row>
+	<entry>speed</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Speed over ground, meters per second.</entry>
+</row>
+<row>
+	<entry>climb</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Climb (positive) or sink (negative) rate, meters per
+	second.</entry>
+</row>
+<row>
+	<entry>epd</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Direction error estimate in degrees, 95% confidence.</entry>
+</row>
+<row>
+	<entry>eps</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Speed error estinmate in meters/sec, 95% confidence.</entry>
+</row>
+<row>
+	<entry>epc</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Climb/sink error estimate in meters/sec, 95% confidence.</entry>
+</row>
+<row>
+	<entry>ecefx</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>ECEF X position in meters.</entry>
+</row>
+<row>
+	<entry>ecefy</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>ECEF Y position in meters.</entry>
+</row>
+<row>
+	<entry>ecefz</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>ECEF Z position in meters.</entry>
+</row>
+<row>
+	<entry>ecefpAcc</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>ECEF position error in meters.</entry>
+</row>
+<row>
+	<entry>ecefvx</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>ECEF X velocity in meters/second.</entry>
+</row>
+<row>
+	<entry>ecefvy</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>ECEF Y velocity in meters/second.</entry>
+</row>
+<row>
+	<entry>ecefvz</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>ECEF Z velocity in meters/second.</entry>
+</row>
+<row>
+	<entry>ecefvAcc</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>ECEF velocity error in meters/second.</entry>
+</row>
+
+</tbody>
+</tgroup>
+</table>
+
+<para>When the C client library parses a response of this kind, it
+will assert validity bits in the top-level set member for each
+field actually received; see gps.h for bitmask names and values.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"TPV","device":"/dev/pts/1",
+    "time":"2005-06-08T10:34:48.283Z","ept":0.005,
+    "lat":46.498293369,"lon":7.567411672,"alt":1343.127,
+    "eph":36.000,"epv":32.321,
+    "track":10.3788,"speed":0.091,"climb":-0.085,"mode":3}
+</programlisting>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>SKY</term>
+<listitem>
+<para>A SKY object reports a sky view of the GPS satellite positions.
+If there is no GPS device available, or no skyview has been reported
+yet, only the "class" field will reliably be present.</para>
+
+<table frame="all" pgwide="0"><title>SKY object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "SKY"</entry>
+</row>
+<row>
+	<entry>device</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Name of originating device</entry>
+</row>
+<row>
+	<entry>time</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Time/date stamp in ISO8601 format, UTC. May have a
+	fractional part of up to .001sec precision.</entry>
+</row>
+<row>
+	<entry>xdop</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Longitudinal dilution of precision, a dimensionless
+	factor which should be multiplied by a base UERE to get an
+	error estimate.</entry>
+</row>
+<row>
+	<entry>ydop</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Latitudinal dilution of precision, a dimensionless
+	factor which should be multiplied by a base UERE to get an
+	error estimate.</entry>
+</row>
+<row>
+	<entry>vdop</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Altitude dilution of precision, a dimensionless
+	factor which should be multiplied by a base UERE to get an
+	error estimate.</entry>
+</row>
+<row>
+	<entry>tdop</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Time dilution of precision, a dimensionless
+	factor which should be multiplied by a base UERE to get an
+	error estimate.</entry>
+</row>
+<row>
+	<entry>hdop</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Horizontal dilution of precision, a dimensionless
+	factor which should be multiplied by a base UERE to get a
+	circular error estimate.</entry>
+</row>
+<row>
+	<entry>pdop</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Spherical dilution of precision, a dimensionless
+	factor which should be multiplied by a base UERE to get an
+	error estimate.</entry>
+</row>
+<row>
+	<entry>gdop</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Hyperspherical dilution of precision, a dimensionless
+	factor which should be multiplied by a base UERE to get an
+	error estimate.</entry>
+</row>
+<row>
+	<entry>satellites</entry>
+	<entry>Yes</entry>
+	<entry>list</entry>
+        <entry>List of satellite objects in skyview</entry>
+</row>
+
+</tbody>
+</tgroup>
+</table>
+
+<para>Many devices compute dilution of precision factors but do not
+include them in their reports.  Many that do report DOPs report only
+HDOP, two-dimensional circular error. <application>gpsd</application>
+always passes through whatever the device actually reports, then
+attempts to fill in other DOPs by calculating the appropriate
+determinants in a covariance matrix based on the satellite view. DOPs
+may be missing if some of these determinants are singular. It can even
+happen that the device reports an error estimate in meters when the
+corresponding DOP is unavailable; some devices use more sophisticated
+error modeling than the covariance calculation.</para>
+
+<para>The satellite list objects have the following elements:</para>
+
+<table frame="all" pgwide="0"><title>Satellite object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>PRN</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>PRN ID of the satellite. 1-63 are GNSS satellites,
+	64-96 are GLONASS satellites, 100-164 are SBAS satellites</entry>
+</row>
+<row>
+	<entry>az</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>Azimuth, degrees from true north.</entry>
+</row>
+<row>
+	<entry>el</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>Elevation in degrees.</entry>
+</row>
+<row>
+	<entry>ss</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>Signal strength in dB.</entry>
+</row>
+<row>
+	<entry>used</entry>
+	<entry>Yes</entry>
+	<entry>boolean</entry>
+        <entry>Used in current solution? (SBAS/WAAS/EGNOS satellites
+	may be flagged used if the solution has corrections from them,
+	but not all drivers make this information available.)</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>Note that satellite objects do not have a "class" field, as
+they are never shipped outside of a SKY object.</para>
+
+<para>When the C client library parses a SKY response, it
+will assert the SATELLITE_SET bit in the top-level set member.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"SKY","device":"/dev/pts/1",
+    "time":"2005-07-08T11:28:07.114Z",
+    "xdop":1.55,"hdop":1.24,"pdop":1.99,
+    "satellites":[
+        {"PRN":23,"el":6,"az":84,"ss":0,"used":false},
+        {"PRN":28,"el":7,"az":160,"ss":0,"used":false},
+        {"PRN":8,"el":66,"az":189,"ss":44,"used":true},
+        {"PRN":29,"el":13,"az":273,"ss":0,"used":false},
+        {"PRN":10,"el":51,"az":304,"ss":29,"used":true},
+        {"PRN":4,"el":15,"az":199,"ss":36,"used":true},
+        {"PRN":2,"el":34,"az":241,"ss":43,"used":true},
+        {"PRN":27,"el":71,"az":76,"ss":43,"used":true}]}
+</programlisting>
+
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>GST</term>
+<listitem>
+<para>A GST object is a pseudorange noise report.</para>
+
+<table frame="all" pgwide="0"><title>GST object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "GST"</entry>
+</row>
+<row>
+	<entry>device</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Name of originating device</entry>
+</row>
+<row>
+	<entry>time</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Time/date stamp in ISO8601 format, UTC. May have a
+	fractional part of up to .001sec precision.</entry>
+</row>
+
+<row>
+	<entry>rms</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Value of the standard deviation of the range inputs to the
+navigation process (range inputs include pseudoranges and DGPS
+corrections).</entry>
+</row>
+
+<row>
+	<entry>major</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Standard deviation of semi-major axis of error ellipse, in meters.</entry>
+</row>
+
+<row>
+	<entry>minor</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Standard deviation of semi-minor axis of error ellipse, in meters.</entry>
+</row>
+
+<row>
+	<entry>orient</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Orientation of semi-major axis of error ellipse, in degrees from true north.</entry>
+</row>
+
+<row>
+	<entry>lat</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Standard deviation of latitude error, in meters.</entry>
+</row>
+
+<row>
+	<entry>lon</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Standard deviation of longitude error, in meters.</entry>
+</row>
+
+<row>
+	<entry>alt</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Standard deviation of altitude error, in meters.</entry>
+</row>
+
+</tbody>
+</tgroup>
+</table>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"GST","device":"/dev/ttyUSB0",
+        "time":"2010-12-07T10:23:07.096Z","rms":2.440,
+        "major":1.660,"minor":1.120,"orient":68.989,
+        "lat":1.600,"lon":1.200,"alt":2.520}
+</programlisting>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>ATT</term>
+<listitem>
+<para>An ATT object is a vehicle-attitude report. It is returned by
+digital-compass and gyroscope sensors; depending on device, it may
+include: heading, pitch, roll, yaw, gyroscope, and magnetic-field
+readings. Because such sensors are often bundled as part of
+marine-navigation systems, the ATT response may also include
+water depth.</para>
+
+<para>The "class" and "mode" fields will reliably be present.  Others
+may be reported or not depending on the specific device type.</para>
+
+<table frame="all" pgwide="0"><title>ATT object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "ATT"</entry>
+</row>
+<row>
+	<entry>device</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Name of originating device</entry>
+</row>
+<row>
+	<entry>time</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Time/date stamp in ISO8601 format, UTC. May have a
+	fractional part of up to .001sec precision.</entry>
+</row>
+<row>
+	<entry>heading</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Heading, degrees from true north.</entry>
+</row>
+<row>
+	<entry>mag_st</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Magnetometer status.</entry>
+</row>
+<row>
+	<entry>pitch</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Pitch in degrees.</entry>
+</row>
+<row>
+	<entry>pitch_st</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Pitch sensor status.</entry>
+</row>
+<row>
+	<entry>yaw</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Yaw in degrees</entry>
+</row>
+<row>
+	<entry>yaw_st</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Yaw sensor status.</entry>
+</row>
+<row>
+	<entry>roll</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Roll in degrees.</entry>
+</row>
+<row>
+	<entry>roll_st</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Roll sensor status.</entry>
+</row>
+<row>
+	<entry>dip</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Local magnetic inclination, degrees, positive when the magnetic
+field points downward (into the Earth).</entry>
+</row>
+<row>
+	<entry>mag_len</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Scalar magnetic field strength.</entry>
+</row>
+<row>
+	<entry>mag_x</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>X component of magnetic field strength.</entry>
+</row>
+<row>
+	<entry>mag_y</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Y component of magnetic field strength.</entry>
+</row>
+<row>
+	<entry>mag_z</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Z component of magnetic field strength.</entry>
+</row>
+<row>
+	<entry>acc_len</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Scalar acceleration.</entry>
+</row>
+<row>
+	<entry>acc_x</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>X component of acceleration.</entry>
+</row>
+<row>
+	<entry>acc_y</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Y component of acceleration.</entry>
+</row>
+<row>
+	<entry>acc_z</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Z component of acceleration.</entry>
+</row>
+<row>
+	<entry>gyro_x</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>X component of acceleration.</entry>
+</row>
+<row>
+	<entry>gyro_y</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Y component of acceleration.</entry>
+</row>
+<row>
+	<entry>depth</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Water depth in meters.</entry>
+</row>
+<row>
+	<entry>temp</entry>
+	<entry>No</entry>
+	<entry>numeric</entry>
+        <entry>Temperature at sensor, degrees centigrade.</entry>
+</row>
+
+
+</tbody>
+</tgroup>
+</table>
+
+<para>The heading, pitch, and roll status codes (if present) vary by device.
+For the TNT Revolution digital compasses, they are coded as follows: </para>
+
+<table frame="all" pgwide="0"><title>Device flags</title>
+<tgroup cols="2" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Code</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>C</entry>
+	<entry>magnetometer calibration alarm</entry>
+</row>
+<row>
+	<entry>L</entry>
+	<entry>low alarm</entry>
+</row>
+<row>
+	<entry>M</entry>
+	<entry>low warning</entry>
+</row>
+<row>
+	<entry>N</entry>
+	<entry>normal</entry>
+</row>
+<row>
+	<entry>O</entry>
+	<entry>high warning</entry>
+</row>
+<row>
+	<entry>P</entry>
+	<entry>high alarm</entry>
+</row>
+<row>
+	<entry>V</entry>
+	<entry>magnetometer voltage level alarm</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+
+<para>When the C client library parses a response of this kind, it
+will assert ATT_IS.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"ATT","time":1270938096.843,
+    "heading":14223.00,"mag_st":"N",
+    "pitch":169.00,"pitch_st":"N", "roll":-43.00,"roll_st":"N",
+    "dip":13641.000,"mag_x":2454.000}
+</programlisting>
+</listitem>
+</varlistentry>
+
+</variablelist>
+
+<para>And here are the commands:</para>
+
+<variablelist>
+
+<varlistentry>
+<term>?VERSION;</term>
+<listitem><para>Returns an object with the following attributes:</para>
+
+<table frame="all" pgwide="0"><title>VERSION object</title>
+<tgroup cols="4" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "VERSION"</entry>
+</row>
+<row>
+	<entry>release</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Public release level</entry>
+</row>
+<row>
+	<entry>rev</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Internal revision-control level.</entry>
+</row>
+<row>
+	<entry>proto_major</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>API major revision level.</entry>
+</row>
+<row>
+	<entry>proto_minor</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>API minor revision level.</entry>
+</row>
+<row>
+	<entry>remote</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>URL of the remote daemon reporting this version. If
+        empty, this is the version of the local daemon.</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>The daemon ships a VERSION response to each client when the
+client first connects to it.</para>
+
+<para>When the C client library parses a response of this kind, it
+will assert the VERSION_SET bit in the top-level set member.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"VERSION","version":"2.40dev",
+    "rev":"06f62e14eae9886cde907dae61c124c53eb1101f",
+    "proto_major":3,"proto_minor":1
+}
+</programlisting>
+
+
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>?DEVICES;</term>
+<listitem><para>Returns a device list object with the
+following elements:</para>
+
+<table frame="all" pgwide="0"><title>DEVICES object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "DEVICES"</entry>
+</row>
+<row>
+	<entry>devices</entry>
+	<entry>Yes</entry>
+	<entry>list</entry>
+        <entry>List of device descriptions</entry>
+</row>
+<row>
+	<entry>remote</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>URL of the remote daemon reporting the device set. If
+        empty, this is a DEVICES response from the local daemon.</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>When the C client library parses a response of this kind, it
+will assert the DEVICELIST_SET bit in the top-level set member.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class"="DEVICES","devices":[
+    {"class":"DEVICE","path":"/dev/pts/1","flags":1,"driver":"SiRF binary"},
+    {"class":"DEVICE","path":"/dev/pts/3","flags":4,"driver":"AIVDM"}]}
+</programlisting>
+
+<para>The daemon occasionally ships a bare DEVICE object to the client
+(that is, one not inside a DEVICES wrapper). The data content of these
+objects will be described later as a response to the ?DEVICE command.</para>
+
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>?WATCH;</term>
+<listitem>
+
+<para>This command sets watcher mode. It also sets or elicits a report
+of per-subscriber policy and the raw bit.  An argument WATCH object
+changes the subscriber's policy. The response describes the
+subscriber's policy. The response will also include a DEVICES
+object.</para>
+
+<para>A WATCH object has the following elements:</para>
+
+<table frame="all" pgwide="0"><title>WATCH object</title>
+<tgroup cols="4" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "WATCH"</entry>
+</row>
+<row>
+	<entry>enable</entry>
+	<entry>No</entry>
+	<entry>boolean</entry>
+        <entry>Enable (true) or disable (false) watcher mode. Default
+	is true.</entry>
+</row>
+<row>
+	<entry>json</entry>
+	<entry>No</entry>
+	<entry>boolean</entry>
+        <entry>Enable (true) or disable (false) dumping of JSON reports.
+	Default is false.</entry>
+</row>
+<row>
+	<entry>nmea</entry>
+	<entry>No</entry>
+	<entry>boolean</entry>
+        <entry>Enable (true) or disable (false) dumping of binary
+	packets as pseudo-NMEA. Default
+	is false.</entry>
+</row>
+<row>
+	<entry>raw</entry>
+        <entry>No</entry>
+        <entry>integer</entry>
+
+	<entry>Controls 'raw' mode. When this attribute is set to 1
+	for a channel, <application>gpsd</application> reports the
+	unprocessed NMEA or AIVDM data stream from whatever device is attached.
+	Binary GPS packets are hex-dumped.  RTCM2 and RTCM3
+        packets are not dumped in raw mode. When this attribute is set to
+	2 for a channel that processes binary data,
+	<application>gpsd</application> reports the received data verbatim
+	without hex-dumping.</entry>
+</row>
+<row>
+	<entry>scaled</entry>
+	<entry>No</entry>
+	<entry>boolean</entry>
+        <entry>If true, apply scaling divisors to output before
+	dumping; default is false.</entry>
+</row>
+<row>
+	<entry>split24</entry>
+	<entry>No</entry>
+	<entry>boolean</entry>
+        <entry>If true, aggregate AIS type24 sentence parts.  If false,
+        report each part as a separate JSON object, leaving the
+        client to match MMSIs and aggregate.  Default is
+        false. Applies only to AIS reports.</entry>
+</row>
+<row>
+	<entry>pps</entry>
+	<entry>No</entry>
+	<entry>boolean</entry>
+        <entry>If true, emit the TOFF JSON message on each cycle and a
+	PPS JSON message when the device issues 1PPS. Default is false.</entry>
+</row>
+<row>
+	<entry>device</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>If present, enable watching only of the specified device
+	rather than all devices.  Useful with raw and NMEA modes
+	in which device responses aren't tagged. Has no effect when
+	used with enable:false.</entry>
+</row>
+<row>
+	<entry>remote</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>URL of the remote daemon reporting the watch set. If
+        empty, this is a WATCH response from the local daemon.</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>There is an additional boolean "timing" attribute which is
+undocumented because that portion of the interface is considered
+unstable and for developer use only.</para>
+
+<para>In watcher mode, GPS reports are dumped as TPV and SKY
+responses. AIS, Subframe and RTCM reporting is described in the next
+section.</para>
+
+<para>When the C client library parses a response of this kind, it
+will assert the POLICY_SET bit in the top-level set member.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"WATCH", "raw":1,"scaled":true}
+</programlisting>
+
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>?POLL;</term>
+<listitem>
+
+<para>The POLL command requests data from the last-seen fixes on all
+active GPS devices.  Devices must previously have been activated by
+?WATCH to be pollable.</para>
+
+<para>Polling can lead to possibly surprising results when it is used
+on a device such as an NMEA GPS for which a complete fix has to be
+accumulated from several sentences. If you poll while those sentences
+are being emitted, the response will contain the last complete fix
+data and may be as much as one cycle time (typically 1 second)
+stale.</para>
+
+<para>The POLL response will contain a timestamped list of TPV objects
+describing cached data, and a timestamped list of SKY objects
+describing satellite configuration. If a device has not seen fixes, it
+will be reported with a mode field of zero.</para>
+
+<table frame="all" pgwide="0"><title>POLL object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "POLL"</entry>
+</row>
+<row>
+	<entry>time</entry>
+	<entry>Yes</entry>
+	<entry>Numeric</entry>
+        <entry>Timestamp in ISO 8601 format. May have a
+	fractional part of up to .001sec precision.</entry>
+</row>
+<row>
+	<entry>active</entry>
+	<entry>Yes</entry>
+	<entry>Numeric</entry>
+        <entry>Count of active devices.</entry>
+</row>
+<row>
+	<entry>tpv</entry>
+	<entry>Yes</entry>
+	<entry>JSON array</entry>
+        <entry>Comma-separated list of TPV objects.</entry>
+</row>
+<row>
+	<entry>sky</entry>
+	<entry>Yes</entry>
+	<entry>JSON array</entry>
+        <entry>Comma-separated list of SKY objects.</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>Here's an example of a POLL response:</para>
+
+<programlisting>
+{"class":"POLL","time":"2010-06-04T10:31:00.289Z","active":1,
+    "tpv":[{"class":"TPV","device":"/dev/ttyUSB0",
+            "time":"2010-09-08T13:33:06.095Z",
+	    "ept":0.005,"lat":40.035093060,
+            "lon":-75.519748733,"track":99.4319,"speed":0.123,"mode":2}],
+    "sky":[{"class":"SKY","device":"/dev/ttyUSB0",
+            "time":1270517264.240,"hdop":9.20,
+            "satellites":[{"PRN":16,"el":55,"az":42,"ss":36,"used":true},
+                          {"PRN":19,"el":25,"az":177,"ss":0,"used":false},
+                          {"PRN":7,"el":13,"az":295,"ss":0,"used":false},
+                          {"PRN":6,"el":56,"az":135,"ss":32,"used":true},
+                          {"PRN":13,"el":47,"az":304,"ss":0,"used":false},
+                          {"PRN":23,"el":66,"az":259,"ss":0,"used":false},
+                          {"PRN":20,"el":7,"az":226,"ss":0,"used":false},
+                          {"PRN":3,"el":52,"az":163,"ss":32,"used":true},
+                          {"PRN":31,"el":16,"az":102,"ss":0,"used":false}
+]}]}
+</programlisting>
+
+<note>
+<para>Client software should not assume the field inventory of the
+POLL response is fixed for all time.  As
+<application>gpsd</application> collects and caches more data from
+more sensor types, those data are likely to find their way
+into this response.</para>
+</note>
+
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>TOFF</term>
+<listitem>
+
+<para>This message is emitted on each cycle and reports the offset
+between the host's clock time and the GPS time at top of second
+(actually, when the first data for the reporting cycle is received).</para>
+
+<para>This message exactly mirrors the PPS message except for two
+details.</para>
+
+<para>TOFF emits no NTP precision, this is assumed to be -2.  See
+the NTP documentation for their definition of precision.</para>
+
+<para>  The TOFF message reports the GPS time as derived from the GPS
+serial data stream.  The PPS message reports the GPS time as derived
+from the GPS PPS pulse.</para>
+
+<para>A TOFF object has the following elements:</para>
+
+<table frame="all" pgwide="0"><title>TOFF object</title>
+<tgroup cols="4" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "TOFF"</entry>
+</row>
+<row>
+	<entry>device</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Name of originating device</entry>
+</row>
+<row>
+	<entry>real_sec</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>seconds from the GPS clock</entry>
+</row>
+<row>
+	<entry>real_nsec</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>nanoseconds from the GPS clock</entry>
+</row>
+<row>
+	<entry>clock_sec</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>seconds from the system clock</entry>
+</row>
+<row>
+	<entry>clock_nsec</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>nanoseconds from the system clock</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>This message is emitted once per second to watchers of a device
+and is intended to report the time stamps of the in-band report of the
+GPS and seconds as reported by the system clock (which may be
+NTP-corrected) when the first valid timestamp of the reporting cycle
+was seen.</para>
+
+<para>The message contains two second/nanosecond pairs: real_sec and
+real_nsec contain the time the GPS thinks it was at the start of the
+current cycle; clock_sec and clock_nsec contain the time the system
+clock thinks it was on receipt of the first timing message of the cycle.
+real_nsec is always to nanosecond precision. clock_nsec is nanosecond
+precision on most systems.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"TOFF","device":"/dev/ttyUSB0",
+     "real_sec":1330212592, "real_nsec":343182,
+     "clock_sec":1330212592,"clock_nsec":343184,
+     "precision":-2}}
+</programlisting>
+
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>PPS</term>
+<listitem>
+
+<para>This message is emitted each time the daemon sees a valid PPS (Pulse
+Per Second) strobe from a device.</para>
+
+<para>This message exactly mirrors the TOFF message except for two
+details.</para>
+
+<para>PPS emits the NTP precision.  See the NTP documentation for their
+definition of precision.</para>
+
+<para>The TOFF message reports the GPS time as derived from the GPS
+serial data stream.  The PPS message reports the GPS time as derived
+from the GPS PPS pulse.</para>
+
+<para>There are various sources of error in the reported clock times.
+The speed of the serial connection between the GPS and the system adds
+a delay to start of cycle detection.  An even bigger error is added
+by the variable computation time inside the GPS.  Taken together the
+time derived from the start of the GPS cycle can have offsets of
+10 millisecond to 700 milliseconds and combined jjitter and wander of
+100 to 300 millisecond.</para>
+
+<para>A PPS object has the following elements:</para>
+
+<table frame="all" pgwide="0"><title>PPS object</title>
+<tgroup cols="4" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "PPS"</entry>
+</row>
+<row>
+	<entry>device</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Name of originating device</entry>
+</row>
+<row>
+	<entry>real_sec</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>seconds from the PPS source</entry>
+</row>
+<row>
+	<entry>real_nsec</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>nanoseconds from the PPS source</entry>
+</row>
+<row>
+	<entry>clock_sec</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>seconds from the system clock</entry>
+</row>
+<row>
+	<entry>clock_nsec</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>nanoseconds from the system clock</entry>
+</row>
+<row>
+	<entry>precision</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>NTP style estimate of PPS precision</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>This message is emitted once per second to watchers of a device
+emitting PPS, and reports the time of the start of the GPS second (when
+the 1PPS arrives) and seconds as reported by the system clock (which
+may be NTP-corrected) at that moment.</para>
+
+<para>The message contains two second/nanosecond pairs: real_sec and
+real_nsec contain the time the GPS thinks it was at the PPS edge;
+clock_sec and clock_nsec contain the time the system clock thinks it was
+at the PPS edge. real_nsec is always to nanosecond precision. clock_nsec
+is nanosecond precision on most systems.</para>
+
+<para>There are various sources of error in the reported clock times.
+For PPS delivered via a real serial-line strobe, serial-interrupt
+latency plus processing time to the timer call should be bounded above
+by about 10 microseconds; that can be reduced to less than 1 microsecond if
+your kernel supports RFC 2783.   USB1.1-to-serial control-line emulation is
+limited to about 1 millisecond. seconds.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"PPS","device":"/dev/ttyUSB0",
+     "real_sec":1330212592, "real_nsec":343182,
+     "clock_sec":1330212592,"clock_nsec":343184,
+     "precision":-3}
+</programlisting>
+
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>OSC</term>
+<listitem>
+
+<para>This message reports the status of a GPS-disciplined oscillator
+(GPSDO).  The GPS PPS output (which has excellent long-term stability)
+is typically used to discipline a local oscillator with much better
+short-term stability (such as a rubidium atomic clock).</para>
+
+<para>An OSC object has the following elements:</para>
+
+<table frame="all" pgwide="0"><title>OSC object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "OSC"</entry>
+</row>
+<row>
+	<entry>device</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Name of originating device.</entry>
+</row>
+<row>
+	<entry>running</entry>
+	<entry>Yes</entry>
+	<entry>boolean</entry>
+        <entry>If true, the oscillator is currently running.  Oscillators may require warm-up time at start of day.</entry>
+</row>
+<row>
+	<entry>reference</entry>
+	<entry>Yes</entry>
+	<entry>boolean</entry>
+        <entry>If true, the oscillator is receiving a GPS PPS signal.</entry>
+</row>
+<row>
+	<entry>disciplined</entry>
+	<entry>Yes</entry>
+	<entry>boolean</entry>
+        <entry>If true, the GPS PPS signal is sufficiently stable and is being used to discipline the local oscillator.</entry>
+</row>
+<row>
+	<entry>delta</entry>
+	<entry>Yes</entry>
+	<entry>numeric</entry>
+        <entry>The time difference (in nanoseconds) between the GPS-disciplined oscillator PPS output pulse and the most recent GPS PPS input pulse.</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"OSC","running":true,"device":"/dev/ttyUSB0",
+    "reference":true,"disciplined":true,"delta":67}
+</programlisting>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>?DEVICE</term>
+<listitem>
+
+<para>This command reports (when followed by ';') the state of a
+device, or sets (when followed by '=' and a DEVICE object)
+device-specific control bits, notably the device's speed and serial
+mode and the native-mode bit.  The parameter-setting form will be rejected if
+more than one client is attached to the channel.</para>
+
+<para>Pay attention to the response, because it is
+possible for this command to fail if the GPS does not support a
+speed-switching command or only supports some combinations of
+serial modes.  In case of failure, the daemon and GPS will
+continue to communicate at the old speed.</para>
+
+<para>Use the parameter-setting form with caution.  On USB and
+Bluetooth GPSes it is also possible for serial mode setting to fail
+either because the serial adaptor chip does not support non-8N1 modes
+or because the device firmware does not properly synchronize the
+serial adaptor chip with the UART on the GPS chipset when the speed
+changes. These failures can hang your device, possibly requiring a GPS
+power cycle or (in extreme cases) physically disconnecting the NVRAM
+backup battery.</para>
+
+<para>A DEVICE object has the following elements:</para>
+
+<table frame="all" pgwide="0"><title>DEVICE object</title>
+<tgroup cols="4" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "DEVICE"</entry>
+</row>
+<row>
+	<entry>path</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Name the device for which the control bits are
+	being reported, or for which they are to be applied. This
+        attribute may be omitted only when there is exactly one
+        subscribed channel.</entry>
+</row>
+<row>
+	<entry>activated</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>Time the device was activated as an ISO8601
+        timestamp. If the device is inactive this attribute is
+        absent.</entry>
+</row>
+<row>
+	<entry>flags</entry>
+	<entry>No</entry>
+	<entry>integer</entry>
+        <entry>Bit vector of property flags.  Currently defined flags are:
+        describe packet types seen so far (GPS, RTCM2, RTCM3,
+	AIS). Won't be reported if empty, e.g. before
+	<application>gpsd</application> has seen identifiable packets
+	from the device.</entry>
+</row>
+<row>
+	<entry>driver</entry>
+	<entry>No</entry>
+	<entry>string</entry>
+        <entry>GPSD's name for the device driver type. Won't be reported before
+	<application>gpsd</application> has seen identifiable packets
+	from the device.</entry>
+</row>
+<row>
+	<entry>subtype</entry>
+	<entry>When the daemon sees a delayed response to a probe for
+	subtype or firmware-version information.</entry>
+	<entry>string</entry>
+	<entry>Whatever version information the device returned.</entry>
+</row>
+<row>
+	<entry>bps</entry>
+	<entry>No</entry>
+	<entry>integer</entry>
+        <entry>Device speed in bits per second.</entry>
+</row>
+<row>
+	<entry>parity</entry>
+        <entry>No</entry>
+        <entry>string</entry>
+	<entry><para>N, O or E for no parity, odd, or even.</para></entry>
+</row>
+<row>
+	<entry>stopbits</entry>
+        <entry>Yes</entry>
+        <entry>string</entry>
+	<entry><para>Stop bits (1 or 2).</para></entry>
+</row>
+<row>
+	<entry>native</entry>
+	<entry>No</entry>
+	<entry>integer</entry>
+        <entry>0 means NMEA mode and 1 means
+	alternate mode (binary if it has one, for SiRF and Evermore chipsets
+	in particular). Attempting to set this mode on a non-GPS
+	device will yield an error.</entry>
+</row>
+<row>
+	<entry>cycle</entry>
+	<entry>No</entry>
+	<entry>real</entry>
+        <entry>Device cycle time in seconds.</entry>
+</row>
+<row>
+	<entry>mincycle</entry>
+	<entry>No</entry>
+	<entry>real</entry>
+        <entry>Device minimum cycle time in seconds. Reported from
+	?DEVICE when (and only when) the rate is switchable. It is
+	read-only and not settable.</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>The serial parameters will (bps, parity, stopbits) be omitted in
+a response describing a TCP/IP source such as an Ntrip, DGPSIP, or AIS
+feed; on a serial device they will always be present.</para>
+
+<para>The contents of the flags field should be interpreted as follows:</para>
+
+<table frame="all" pgwide="0"><title>Device flags</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>C #define</entry>
+	<entry>Value</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>SEEN_GPS</entry>
+	<entry>0x01</entry>
+	<entry>GPS data has been seen on this device</entry>
+</row>
+<row>
+	<entry>SEEN_RTCM2</entry>
+	<entry>0x02</entry>
+	<entry>RTCM2 data has been seen on this device</entry>
+</row>
+<row>
+	<entry>SEEN_RTCM3</entry>
+	<entry>0x04</entry>
+	<entry>RTCM3 data has been seen on this device</entry>
+</row>
+<row>
+	<entry>SEEN_AIS</entry>
+	<entry>0x08</entry>
+	<entry>AIS data has been seen on this device</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<!--
+<para>The mincycle member may be 0, indicating no hard lower limit on the
+cycle time. On an NMEA device of this kind it is possible to try to
+push more characters through per cycle than the time to transmit will
+allow. You must set the time high enough to let all sentences come
+through.  Here are the maxima to use for computation:</para>
+
+<table frame='all'>
+<tgroup cols='2'>
+<tbody>
+<row><entry>ZDA       </entry><entry>36</entry></row>
+<row><entry>GLL       </entry><entry>47</entry></row>
+<row><entry>GGA       </entry><entry>82</entry></row>
+<row><entry>VTG       </entry><entry>46</entry></row>
+<row><entry>RMC       </entry><entry>77</entry></row>
+<row><entry>GSA       </entry><entry>67</entry></row>
+<row><entry>GSV       </entry><entry>60 (per line, thus 180 for a set of 3)</entry> </row>
+</tbody>
+</tgroup>
+</table>
+
+<para>The transmit time for a cycle (which must be less than 1 second)
+is the total character count multiplied by 10 and divided by the baud
+rate. A typical budget is GGA, RMC, GSA, 3*GSV = 82+75+67+(3*60) =
+404.</para>
+-->
+
+<para>When the C client library parses a response of this kind, it
+will assert the DEVICE_SET bit in the top-level set member.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"DEVICE","bps":4800,"parity":"N","stopbits":1,"native":0}
+</programlisting>
+
+</listitem>
+</varlistentry>
+
+</variablelist>
+
+<para>When a client is in watcher mode, the daemon will ship it DEVICE
+notifications when a device is added to the pool or
+deactivated.</para>
+
+<para>When the C client library parses a response of this kind, it
+will assert the DEVICE_SET bit in the top-level set member.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"DEVICE","path":"/dev/pts1","activated":0}
+</programlisting>
+
+<para>The daemon may ship an error object in response to a
+syntactically invalid command line or unknown command. It has
+the following elements:</para>
+
+<table frame="all" pgwide="0"><title>ERROR notification object</title>
+<tgroup cols="4" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Always?</entry>
+	<entry>Type</entry>
+	<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+        <entry>Fixed: "ERROR"</entry>
+</row>
+<row>
+	<entry>message</entry>
+	<entry>Yes</entry>
+	<entry>string</entry>
+	<entry>Textual error message</entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"ERROR","message":"Unrecognized request '?FOO'"}
+</programlisting>
+
+<para>When the C client library parses a response of this kind, it
+will assert the ERR_SET bit in the top-level set member.</para>
+
+</refsect1>
+
+<refsect1 id='rtcm2'><title>RTCM2</title>
+
+<para>RTCM-104 is a family of serial protocols used for broadcasting pseudorange
+corrections from differential-GPS reference stations. Many GPS receivers can
+accept these corrections to improve their reporting accuracy.</para>
+
+<para>RTCM-104 comes in two major and incompatible flavors, 2.x and
+3.x.  Each major flavor has minor (compatible) revisions.</para>
+
+<para>The applicable standard for RTCM Version 2.x is <citetitle>RTCM
+Recommended Standards for Differential NAVSTAR GPS Service</citetitle>
+RTCM Paper 194-93/SC 104-STD. For RTCM 3.1 it is <citetitle>RTCM Paper
+177-2006-SC104-STD</citetitle>.  Ordering instructions for both
+standards are accessible from the website of the <ulink
+url='http://www.rtcm.org/'>Radio Technical Commission for Maritime
+Services</ulink> under "Publications".</para>
+
+<refsect2 id='wire-format'><title>RTCM WIRE TRANSMISSIONS</title>
+
+<para>Differential-GPS correction stations consist of a GPS reference
+receiver coupled to a low frequency (LF) transmitter.  The GPS
+reference receiver is a survey-grade GPS that does GPS carrier
+tracking and can work out its own position to a few millimeters.  It
+generates range and range-rate corrections and encodes them into
+RTCM104. It ships the RTCM104 to the LF transmitter over serial rs-232
+signal at 100 baud or 200 baud depending on the requirements of the
+transmitter.</para>
+
+<para>The LF transmitter broadcasts the approximately 300khz radio
+signal that differential-GPS radio receivers pick up.  Transmitters
+that are meant to have a higher range will need to transmit at the
+slower rate.  The higher the data rate the harder it will be for the
+remote radio receiver to receive with a good signal-to-noise ration.
+(Higher data rate signals can't be averaged over as long a time frame,
+hence they appear noisier.)</para>
+
+</refsect2>
+<refsect2 id='rtcm-wire-format'><title>RTCM WIRE FORMATS</title>
+
+<para>An RTCM 2.x message consists of a sequence of up to 33 30-bit
+words. The 24 most significant bits of each word are data and the six
+least significant bits are parity. The parity algorithm used is the
+same ISGPS-2000 as that used on GPS satellite downlinks.  Each RTCM
+2.x message consists of two header words followed by zero or more data
+words, depending upon message type.</para>
+
+<para>An RTCM 3.x message begins with a fixed leader byte 0xD3.  That
+is followed by six bits of version information and 10 bits of payload
+length information.  Following that is the payload; following the
+payload is a 3-byte checksum of the payload using the Qualcomm CRC-24Q
+algorithm.</para>
+
+</refsect2>
+<refsect2 id='rtcm2-dump-format2'><title>RTCM2 JSON FORMAT</title>
+
+<para>Each RTCM2 message is dumped as a single JSON object per
+message, with the message fields as attributes of that object.  Arrays
+of satellite, station, and constellation statistics become arrays of
+JSON sub-objects. Each sentence will normally also have a "device"
+field containing the pathname of the originating device.</para>
+
+<para>All attributes other than the device field are mandatory. Header
+attributes are emitted before others.</para>
+
+<refsect3><title>Header portion</title>
+
+<table frame="all" pgwide="0"><title>SKY object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>class</entry>
+	<entry>string</entry>
+        <entry><para>Fixed: "RTCM2".</para></entry>
+</row>
+<row>
+	<entry>type</entry>
+	<entry>integer</entry>
+        <entry><para>Message type (1-9).</para></entry>
+</row>
+<row>
+	<entry>station_id</entry>
+	<entry>integer</entry>
+        <entry><para>The id of the GPS reference receiver. The
+	LF transmitters also have (different) id numbers.</para></entry>
+</row>
+<row>
+	<entry>zcount</entry>
+	<entry>real</entry>
+        <entry><para>The reference time of the
+	corrections in the message in seconds within the current hour. Note
+	that it is in GPS time, which is some seconds ahead of UTC (see the
+	U.S. Naval Observatory's <ulink
+	url="ftp://maia.usno.navy.mil/ser7/tai-utc.dat">table of leap second
+	corrections</ulink>).</para></entry>
+</row>
+<row>
+	<entry>seqnum</entry>
+	<entry>integer</entry>
+        <entry><para>Sequence number. Only 3 bits wide, wraps after 7.</para></entry>
+</row>
+<row>
+	<entry>length</entry>
+	<entry>integer</entry>
+        <entry><para>The number of words after the header that comprise the
+        message.</para></entry>
+</row>
+<row>
+	<entry>station_health</entry>
+	<entry>integer</entry>
+        <entry><para>Station transmission status. Indicates the health of
+        the beacon as a reference source.  Any nonzero value means the
+        satellite is probably transmitting bad data and should not be
+        used in a fix. 6 means the transmission is unmonitored. 7
+        means the station is not working properly. Other values are
+        defined by the beacon operator.</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>&lt;message type&gt; is one of</para>
+
+<variablelist>
+<varlistentry>
+<term>1</term>
+<listitem><para>full corrections - one message containing corrections for
+all GPS satellites in view. This is not common.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>3</term>
+<listitem><para>reference station parameters - the position of the
+reference station GPS antenna.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>4</term>
+<listitem><para>datum &mdash; the datum to which the DGPS data is
+referred.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>5</term>
+<listitem><para>constellation health &mdash; information about the
+satellites the beacon can see.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>6</term>
+<listitem><para>null message &mdash; just a filler.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>7</term>
+<listitem><para>radio beacon almanac &mdash; information about this or other beacons.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>9</term>
+<listitem><para>subset corrections &mdash; a message containing corrections
+for only a subset of the GPS satellites in view.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>16</term>
+<listitem><para>special message &mdash; a text message from the beacon
+operator.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>31</term>
+<listitem><para>GLONASS subset corrections &mdash; a message
+containing corrections for a set of the GLONASS satellites in
+view.</para></listitem>
+</varlistentry>
+
+
+</variablelist>
+
+</refsect3>
+<refsect3><title>Type 1 and 9: Correction data</title>
+
+<para>One or more satellite objects follow the header for type 1 or type 9
+messages. Here is the format:</para>
+
+<table frame="all" pgwide="0"><title>Satellite object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>ident</entry>
+	<entry>integer</entry>
+        <entry><para>The PRN number of the satellite for which this is
+	correction data.</para></entry>
+</row>
+<row>
+	<entry>udre</entry>
+	<entry>integer</entry>
+        <entry><para>User Differential Range Error (0-3). See the
+        table following for values.</para></entry>
+</row>
+<row>
+	<entry>iod</entry>
+	<entry>integer</entry>
+        <entry><para>Issue Of Data, matching the IOD for the current
+        ephemeris of this satellite, as transmitted by the satellite.
+        The IOD is a unique tag that identifies the ephemeris; the GPS
+        using the DGPS correction and the DGPS generating the data
+        must use the same orbital positions for the
+        satellite.</para></entry>
+</row>
+<row>
+	<entry>prc</entry>
+	<entry>real</entry>
+        <entry><para>The pseudorange error in meters for this
+        satellite as measured by the beacon reference receiver at the
+        epoch indicated by the z_count in the parent
+        record.</para></entry>
+</row>
+<row>
+	<entry>rrc</entry>
+	<entry>real</entry>
+        <entry><para>The rate of change of pseudorange error in
+        meters/sec for this satellite as measured by the beacon
+        reference receiver at the epoch indicated by the z_count field
+        in the parent record. This is used to calculate pseudorange
+        errors at other epochs, if required by the GPS
+        receiver.</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>User Differential Range Error values are as follows:</para>
+
+<table frame="all" pgwide="0"><title>UDRE values</title>
+<tgroup cols="2" align="left" colsep="1" rowsep="1">
+<tbody>
+<row><entry>0</entry><entry>1-sigma error	&lt;= 1m</entry></row>
+<row><entry>1</entry><entry>1-sigma error	&lt;= 4m</entry></row>
+<row><entry>2</entry><entry>1-sigma error	&lt;= 8m</entry></row>
+<row><entry>3</entry><entry>1-sigma error	&gt;  8m</entry></row>
+</tbody>
+</tgroup>
+</table>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"RTCM2","type":1,
+    "station_id":688,"zcount":843.0,"seqnum":5,"length":19,"station_health":6,
+    "satellites":[
+	{"ident":10,"udre":0,"iod":46,"prc":-2.400,"rrc":0.000},
+	{"ident":13,"udre":0,"iod":94,"prc":-4.420,"rrc":0.000},
+	{"ident":7,"udre":0,"iod":22,"prc":-5.160,"rrc":0.002},
+	{"ident":2,"udre":0,"iod":34,"prc":-6.480,"rrc":0.000},
+	{"ident":4,"udre":0,"iod":47,"prc":-8.860,"rrc":0.000},
+	{"ident":8,"udre":0,"iod":76,"prc":-7.980,"rrc":0.002},
+	{"ident":5,"udre":0,"iod":99,"prc":-8.260,"rrc":0.002},
+	{"ident":23,"udre":0,"iod":81,"prc":-8.060,"rrc":0.000},
+	{"ident":16,"udre":0,"iod":70,"prc":-11.740,"rrc":0.000},
+	{"ident":30,"udre":0,"iod":4,"prc":-18.960,"rrc":-0.006},
+	{"ident":29,"udre":0,"iod":101,"prc":-24.960,"rrc":-0.002}
+]}
+</programlisting>
+
+</refsect3>
+<refsect3><title>Type 3: Reference Station Parameters</title>
+
+<para>Here are the payload members of a type 3 (Reference Station
+Parameters) message:</para>
+
+<table frame="all" pgwide="0"><title>Reference Station Parameters</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>x</entry>
+	<entry>real</entry>
+        <entry><para>ECEF X coordinate.</para></entry>
+</row>
+<row>
+	<entry>y</entry>
+	<entry>real</entry>
+        <entry><para>ECEF Y coordinate.</para></entry>
+</row>
+<row>
+	<entry>z</entry>
+	<entry>real</entry>
+        <entry><para>ECEF Z coordinate.</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>The coordinates are the position of the station, in meters to two
+decimal places, in Earth Centred Earth Fixed coordinates.
+These are usually referred to the WGS84 reference frame, but may
+be referred to NAD83 in the US (essentially identical to WGS84 for
+all except geodesists), or to some other reference frame in other
+parts of the world.</para>
+
+<para>An invalid reference message is represented by a type 3 header
+without payload fields.</para>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"RTCM2","type":3,
+    "station_id":652,"zcount":1657.2,"seqnum":2,"length":4,"station_health":6,
+    "x":3878620.92,"y":670281.40,"z":5002093.59
+}
+</programlisting>
+
+</refsect3>
+<refsect3><title>Type 4: Datum</title>
+
+<para>Here are the payload members of a type 4 (Datum) message:</para>
+
+<table frame="all" pgwide="0"><title>Datum</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>dgnss_type</entry>
+	<entry>string</entry>
+        <entry><para>Either "GPS", "GLONASS", "GALILEO", or
+        "UNKNOWN".</para></entry>
+</row>
+<row>
+	<entry>dat</entry>
+	<entry>integer</entry>
+        <entry><para>0 or 1 and indicates the sense of the offset
+        shift given by dx, dy, dz. dat = 0 means that the station
+        coordinates (in the reference message) are referred to a local
+        datum and that adding dx, dy, dz to that position will render
+        it in GNSS coordinates (WGS84 for GPS). If dat = 1 then the
+        ref station position is in GNSS coordinates and adding dx, dy,
+        dz will give it referred to the local datum.</para></entry>
+</row>
+<row>
+	<entry>datum_name</entry>
+	<entry>string</entry>
+        <entry><para>A standard name for the datum.</para></entry>
+</row>
+
+<row>
+	<entry>dx</entry>
+	<entry>real</entry>
+        <entry><para>X offset.</para></entry>
+</row>
+<row>
+	<entry>dy</entry>
+	<entry>real</entry>
+        <entry><para>Y offset.</para></entry>
+</row>
+<row>
+	<entry>dz</entry>
+	<entry>real</entry>
+        <entry><para>Z offset.</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>&lt;dx&gt; &lt;dy&gt; &lt;dz&gt; are offsets to convert from
+local datum to GNSS datum or vice versa. These fields are
+optional.</para>
+
+<para>An invalid datum message is represented by a type 4 header
+without payload fields.</para>
+
+</refsect3>
+<refsect3><title>Type 5: Constellation Health</title>
+
+<para>One or more of these follow the header for type 5 messages &mdash; one
+for each satellite.</para>
+
+<para>Here is the format:</para>
+
+<table frame="all" pgwide="0"><title>Constellation health</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>ident</entry>
+	<entry>integer</entry>
+        <entry><para>The PRN number of the satellite.</para></entry>
+</row>
+<row>
+	<entry>iodl</entry>
+	<entry>bool</entry>
+        <entry><para>True indicates that this information relates to
+        the satellite information in an accompanying type 1 or type 9
+        message.</para></entry>
+</row>
+<row>
+	<entry>health</entry>
+	<entry>integer</entry>
+        <entry>0 indicates that the satellite is healthy. Any other value
+	indicates a problem (coding is not known).<para></para></entry>
+</row>
+<row>
+	<entry>snr</entry>
+	<entry>integer</entry>
+        <entry><para>The carrier/noise ratio of the received signal in
+        the range 25 to 55 dB(Hz).</para></entry>
+</row>
+<row>
+	<entry>health_en</entry>
+	<entry>bool</entry>
+        <entry><para>If set to True it indicates that the satellite is
+        healthy even if the satellite navigation data says it is
+        unhealthy.</para></entry>
+</row>
+<row>
+	<entry>new_data</entry>
+	<entry>bool</entry>
+        <entry>True indicates that the IOD for this satellite will
+        soon be updated in type 1 or 9 messages.<para></para></entry>
+</row>
+<row>
+	<entry>los_warning</entry>
+	<entry>bool</entry>
+        <entry><para>Line-of-sight warning. True indicates that the
+        satellite will shortly go unhealthy.</para></entry>
+</row>
+<row>
+	<entry>tou</entry>
+	<entry>integer</entry>
+        <entry><para>Healthy time remaining in seconds.</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+</refsect3>
+<refsect3><title>Type 6: Null</title>
+
+<para>This just indicates a null message. There are no payload fields.</para>
+</refsect3>
+
+<refsect3><title>Unknown message</title>
+
+<para>This format is used to dump message words in hexadecimal when the
+message type field doesn't match any of the known ones.</para>
+
+<para>Here is the format:</para>
+
+<table frame="all" pgwide="0"><title>Unknown Message</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>data</entry>
+	<entry>list</entry>
+        <entry><para>A list of strings.</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>Each string in the array is a hex literal representing 30 bits
+of information, after parity checks and inversion.  The high two bits
+should be ignored.</para>
+
+</refsect3>
+<refsect3><title>Type 7: Radio Beacon Almanac</title>
+
+<para>Here is the format:</para>
+
+<table frame="all" pgwide="0"><title>Contellation health</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>lat</entry>
+	<entry>real</entry>
+        <entry><para>Latitude in degrees, of the LF transmitter
+        antenna for the station for which this is an almanac.  North
+        is positive.</para></entry>
+</row>
+<row>
+	<entry>lon</entry>
+	<entry>real</entry>
+        <entry><para>Longitude in degrees, of the LF transmitter
+        antenna for the station for which this is an almanac.
+        East is positive.</para></entry>
+</row>
+<row>
+	<entry>range</entry>
+	<entry>integer</entry>
+        <entry>Published range of the station in km.<para></para></entry>
+</row>
+<row>
+	<entry>frequency</entry>
+	<entry>real</entry>
+        <entry><para>Station broadcast frequency in kHz.</para></entry>
+</row>
+<row>
+	<entry>health</entry>
+	<entry>integer</entry>
+        <entry><para>&lt;health&gt; is the health of the station for
+        which this is an almanac. If it is non-zero, the station is
+        issuing suspect data and should not be used for fixes.  The
+        ITU and RTCM104 standards differ about the mode detailed
+        interpretation of the &lt;health&gt; field and even about its
+        bit width.
+<!--
+From itu p.9 just under the type7 msg figure:
+
+    *** Radiobeacon health:
+                  00     (0) Radiobeacon operation normal
+                  01     (1) No integrity monitor operating
+                  10     (2) No information available
+                  11     (3) Do not use this radiobeacon
+RTCM104, in the other hand, makes it 3 bits wide.
+
+The Sager documentation said health has the same meaning as in the header.
+but this cannot be true unless the field is 3 bits wide.
+-->
+	</para></entry>
+</row>
+<row>
+	<entry>station_id</entry>
+	<entry>integer</entry>
+        <entry><para>The id of the transmitter. This is not the same
+        as the reference id in the header, the latter being the id of
+        the reference receiver. <!-- John Sager noted: "However I know
+	of at least one station that gets it wrong." --></para></entry>
+</row>
+<row>
+	<entry>bitrate</entry>
+	<entry>integer</entry>
+        <entry><para>The transmitted bitrate.</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"RTCM2","type":9,"station_id":268,"zcount":252.6,
+        "seqnum":4,"length":5,"station_health":0,
+        "satellites":[
+            {"ident":13,"udre":0,"iod":3,"prc":-25.940,"rrc":0.066},
+            {"ident":2,"udre":0,"iod":73,"prc":0.920,"rrc":-0.080},
+            {"ident":8,"udre":0,"iod":22,"prc":23.820,"rrc":0.014}
+]}
+</programlisting>
+
+</refsect3>
+<refsect3><title>Type 13: GPS Time of Week</title>
+
+<para>Here are the payload members of a type 13 (Groumf Tramitter Parameters)
+message:</para>
+
+<table frame="all" pgwide="0"><title>Grund Transmitter Parameters</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>status</entry>
+	<entry>bool</entry>
+        <entry><para>If True, signals user to expect a type 16 explanatory
+	message associated with this station. Probably indicates some
+	sort of unusual event.</para></entry>
+</row>
+<row>
+	<entry>rangeflag</entry>
+	<entry>bool</entry>
+        <entry><para>If True, indicates that the estimated range is
+	different from that found in the Type 7 message (which contains the
+	beacon's listed range). Generally indicates a range reduction due to
+	causes such as poor ionospheric conditions or reduced transmission
+	power.</para></entry>
+</row>
+<row>
+	<entry>lat</entry>
+	<entry>real</entry>
+        <entry><para>Degrees latitude, signed.
+	Positive is N, negative is S.</para></entry>
+</row>
+<row>
+	<entry>lon</entry>
+	<entry>real</entry>
+        <entry><para>Degrees longitude, signed.
+	Positive is E, negative is W.</para></entry>
+</row>
+<row>
+	<entry>range</entry>
+	<entry>integer</entry>
+        <entry><para>Transmission range in km (1-1024).</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>This message type replaces message type 3 (Reference Station Parameters)
+in RTCM 2.3.</para>
+
+</refsect3>
+<refsect3><title>Type 14: GPS Time of Week</title>
+
+<para>Here are the payload members of a type 14 (GPS Time of Week)
+message:</para>
+
+<table frame="all" pgwide="0"><title>Reference Station Parameters</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>week</entry>
+	<entry>integer</entry>
+        <entry><para>GPS week (0-123).</para></entry>
+</row>
+<row>
+	<entry>hour</entry>
+	<entry>integer</entry>
+        <entry><para>Hour of week (0-167).</para></entry>
+</row>
+<row>
+	<entry>leapsecs</entry>
+	<entry>integer</entry>
+        <entry><para>Leap Seconds (0-63).</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"RTCM2","type":14,"station_id":652,"zcount":1657.2,
+        "seqnum":3,"length":1,"station_health":6,"week":601,"hour":109,
+        "leapsecs":15}
+</programlisting>
+
+</refsect3>
+<refsect3><title>Type 16: Special Message</title>
+
+<table frame="all" pgwide="0"><title>Special Message</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>message</entry>
+	<entry>string</entry>
+        <entry><para>A text message sent by the beacon operator.</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+</refsect3>
+<refsect3><title>Type 31: Correction data</title>
+
+<para>One or more GLONASS satellite objects follow the header for type
+1 or type 9 messages. Here is the format:</para>
+
+<table frame="all" pgwide="0"><title>Satellite object</title>
+<tgroup cols="3" align="left" colsep="1" rowsep="1">
+<thead>
+<row>
+	<entry>Name</entry>
+	<entry>Type</entry>
+	<entry><para>Description</para></entry>
+</row>
+</thead>
+<tbody>
+<row>
+	<entry>ident</entry>
+	<entry>integer</entry>
+        <entry><para>The PRN number of the satellite for which this is
+	correction data.</para></entry>
+</row>
+<row>
+	<entry>udre</entry>
+	<entry>integer</entry>
+        <entry><para>User Differential Range Error (0-3). See the
+        table following for values.</para></entry>
+</row>
+<row>
+	<entry>change</entry>
+	<entry>boolean</entry>
+        <entry><para>Change-of-ephemeris bit.</para></entry>
+</row>
+<row>
+	<entry>tod</entry>
+	<entry>uinteger</entry>
+        <entry><para>Count of 30-second periods since the top of the
+	hour.</para></entry>
+</row>
+<row>
+	<entry>prc</entry>
+	<entry>real</entry>
+        <entry><para>The pseudorange error in meters for this
+        satellite as measured by the beacon reference receiver at the
+        epoch indicated by the z_count in the parent
+        record.</para></entry>
+</row>
+<row>
+	<entry>rrc</entry>
+	<entry>real</entry>
+        <entry><para>The rate of change of pseudorange error in
+        meters/sec for this satellite as measured by the beacon
+        reference receiver at the epoch indicated by the z_count field
+        in the parent record. This is used to calculate pseudorange
+        errors at other epochs, if required by the GPS
+        receiver.</para></entry>
+</row>
+</tbody>
+</tgroup>
+</table>
+
+<para>Here's an example:</para>
+
+<programlisting>
+{"class":"RTCM2","type":31,"station_id":652,"zcount":1642.2,
+    "seqnum":0,"length":14,"station_health":6,
+    "satellites":[
+        {"ident":5,"udre":0,"change":false,"tod":0,"prc":132.360,"rrc":0.000},
+        {"ident":15,"udre":0,"change":false,"tod":0,"prc":134.840,"rrc":0.002},
+        {"ident":14,"udre":0,"change":false,"tod":0,"prc":141.520,"rrc":0.000},
+        {"ident":6,"udre":0,"change":false,"tod":0,"prc":127.000,"rrc":0.000},
+        {"ident":21,"udre":0,"change":false,"tod":0,"prc":128.780,"rrc":0.000},
+        {"ident":22,"udre":0,"change":false,"tod":0,"prc":125.260,"rrc":0.002},
+        {"ident":20,"udre":0,"change":false,"tod":0,"prc":117.280,"rrc":-0.004},
+        {"ident":16,"udre":0,"change":false,"tod":17,"prc":113.460,"rrc":0.018}
+]}
+</programlisting>
+
+</refsect3>
+</refsect2>
+</refsect1>
+
+<refsect1 id='dump-format3'><title>RTCM3 DUMP FORMAT</title>
+
+<para>The support for RTCM104v3 dumping is incomplete and buggy.  Do not
+attempt to use it for production! Anyone interested in it should read
+the source code.</para>
+</refsect1>
+
+<refsect1 id='ais'><title>AIS DUMP FORMATS</title>
+
+<para>AIS support is an extension.  It may not be present if your
+instance of <application>gpsd</application> has been built with
+a restricted feature set.</para>
+
+<para>AIS packets are dumped as JSON objects with class "AIS".  Each
+AIS report object contains a "type" field giving the AIS message type
+and a "scaled" field telling whether the remainder of the fields are
+dumped in scaled or unscaled form. (These will be emitted before any
+type-specific fields.) It will also contain a "device" field naming
+the data source.  Other fields have names and types as specified in
+the <citetitle>AIVDM/AIVDO Protocol Decoding</citetitle> document on
+the GPSD project website; each message field table may be directly
+interpreted as a specification for the members of the corresponding
+JSON object type.</para>
+
+<para>By default, certain scaling and conversion operations are
+performed for JSON output.  Latitudes and longitudes are scaled to
+decimal degrees rather than the native AIS unit of 1/10000th of a
+minute of arc.  Ship (but not air) speeds are scaled to knots rather
+than tenth-of-knot units. Rate of turn may appear as "nan" if is
+unavailable, or as one of the strings "fastright" or "fastleft" if it
+is out of the AIS encoding range; otherwise it is quadratically mapped
+back to the turn sensor number in degrees per minute. Vessel draughts
+are converted to decimal meters rather than native AIS
+decimeters. Various other scaling conversions are described in
+<citetitle>"AIVDM/AIVDO Protocol Decoding"</citetitle>.</para>
+
+</refsect1>
+<refsect1 id='subframe'><title>SUBFRAME DUMP FORMATS</title>
+
+<para>Subframe support is always compiled into
+<application>gpsd</application> but many GPSes do not output subframe data
+or the <application>gpsd</application> driver may not support subframes.
+</para>
+
+<para>Subframe packets are dumped as JSON objects with class "SUBFRAME".
+Each subframe report object contains a "frame" field giving the subframe
+number, a "tSV" field for the transmitting satellite number, a "TOW17"
+field containing the 17 MSBs of the start of the next 12-second message
+and a "scaled" field telling whether the remainder of the fields are
+dumped in scaled or unscaled form. It will also contain a "device" field
+naming the data source.  Each SUBFRAME object will have a sub-object
+specific to that subframe page type.  Those sub-object fields have names
+and types similar to those specified in the IS-GPS-200E document; each
+message field table may be directly interpreted as a specification for
+the members of the corresponding JSON object type.</para>
+
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>The protocol was designed and documented by Eric S. Raymond.</para>
+</refsect1>
+
+</refentry>
diff --git a/man/gpsdctl.xml b/man/gpsdctl.xml
new file mode 100644
index 00000000..d47128c9
--- /dev/null
+++ b/man/gpsdctl.xml
@@ -0,0 +1,81 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gpsdctl.8'>
+<refentryinfo><date>25 Jun 2011</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpsdctl</refentrytitle>
+<manvolnum>8</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpsdctl</refname>
+<refpurpose>tool for sending commands to gpsd over its control socket</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gpdsctl</command>
+ 	<arg choice='plain'><replaceable>action</replaceable></arg>
+ 	<arg choice='plain'><replaceable>device</replaceable></arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para>This is a tool for sending an instance of
+<application>gpsd</application> commands over its control socket to
+add or remove devices from the daemon's device list. It is not
+intended to be called by users, but rather by the Linux hotplug
+system and similar facilities.</para>
+
+<para>The action argument may be "add" or "remove". If no daemon
+instance is running when an add is requested, this program will launch
+one.</para>
+
+<para>The "device" argument should be the pathname of a device. A
+device on the list will be opened to read sensor data whenever a
+client requests a watch.</para>
+
+<para>Two environment variables are
+interpreted. <envar>GPSD_SOCKET</envar> sets the location of the
+control socket.  It defaults to
+<filename>/var/run/gpsd.sock</filename> if the effective user ID of
+this program is root, <filename>/tmp/gpsd.sock</filename>
+otherwise.</para>
+
+<para><envar>GPSD_OPTIONS</envar>
+may be a list of options to be passed to <application>gpsd</application>
+when this tool launches it.  It defaults to an empty string.</para>
+</refsect1>
+
+<refsect1 id='exit_status'><title>RETURN VALUES</title>
+
+<para>1 if the action was unknown or the write to the control socket
+failed, 0 otherwise</para>
+
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>Eric S. Raymond <email>esr@thyrsus.com</email>.</para>
+</refsect1>
+</refentry>
diff --git a/man/gpsdecode.xml b/man/gpsdecode.xml
new file mode 100644
index 00000000..b7368dc7
--- /dev/null
+++ b/man/gpsdecode.xml
@@ -0,0 +1,147 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gpsdecode.1'>
+<refentryinfo><date>13 Jul 2005</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpsdecode</refentrytitle>
+<manvolnum>1</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpsdecode</refname>
+<refpurpose>decode GPS, RTCM or AIS streams into a readable format</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gpsdecode</command>
+      <arg choice='opt'>-c</arg>
+      <arg choice='opt'>-d</arg>
+      <arg choice='opt'>-e</arg>
+      <arg choice='opt'>-j</arg>
+      <arg choice='opt'>-m</arg>
+      <arg choice='opt'>-n</arg>
+      <arg choice='opt'>-s</arg>
+      <arg choice='opt'>-t <replaceable>typelist</replaceable></arg>
+      <arg choice='opt'>-u</arg>
+      <arg choice='opt'>-v</arg>
+      <arg choice='opt'>-D <replaceable>debuglevel</replaceable></arg>
+      <arg choice='opt'>-V</arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para>This tool is a batch-mode decoder for NMEA and various binary
+packet formats associated with GPS, AIS, and differential-correction
+services.  It produces a JSON dump on standard output from binary on
+standard input. The JSON is the same format documented in
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>;
+this tool uses the same decoding logic as gpsd, but with a simpler
+interface intended for batch processing of data files.</para>
+
+<para>All sensor-input formats known to the GPSD project can be
+decoded by this tool.  These include: NMEA, AIVDM (the NMEA-derived
+sentence format used by AIS, the marine Automatic Identification
+System), RTCM2, and all supported GPS binary formats (notably
+including SiRF). See
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+for applicable standards and known limitations of the decoding
+logic.</para>
+
+<para>You can use this tool with
+<citerefentry><refentrytitle>nc</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+to examine AIS feeds from AIS pooling services, RTCM feeds from RTCM
+receivers or NTRIP broadcasters.</para>
+
+</refsect1>
+<refsect1 id='options'><title>OPTIONS</title>
+
+<para>The <option>-d</option> option tells the program to decode
+packets presented on standard input to standard output. This is the
+default behavior.</para>
+
+<para>The <option>-j</option> explicitly sets the output dump format
+to JSON (the default behavior).</para>
+
+<para>With the <option>-m</option> option, dump minimum lengths for
+each packet type in the input (ignoring comment packets).  This is
+probably of interest only to GSD developers.</para>
+
+<para>The <option>-n</option> enables dumping in generated
+pseudo-NME0183.</para>
+
+<para>The <option>-e</option> option option tells the program to
+encode JSON on standard input to JSON on standard output. This option
+is only useful for regression-testing of the JSON dumping and parsing
+code.</para>
+
+<para>The <option>-s</option> option option tells the program to report
+AIS Type 24 sentence halves separately rather than attempting to
+aggregate them.</para>
+
+<para>The <option>-t</option> accepts a comma-separated list of
+numeric types.  Packets with a numeric AIS, RTCM2, or RTCM3 type are
+passed through and output only if they match a type in the
+list. Packets of other kinds (in particular GPS packets) are
+passed through unconditionally.</para>
+
+<para>The <option>-u</option> suppresses scaling of AIS data to float
+quantities and text expansion of numeric codes.  A dump with this
+option is lossless.</para>
+
+<para>The <option>-v</option> enables dumping of textual packets
+to output as they are received on input, immediately preceding
+corresponding output.</para>
+
+<para>The <option>-c</option> sets the AIS dump format to separate
+fields with an ASCII pipe symbol.  Fields are dumped in the order they
+occur in the AIS packet. Numerics are not scaled (-u is
+forced). Strings are unpacked from six-bit to full ASCII</para>
+
+<para>The <option>-V</option> option directs the program to emit its
+version number, then exit.</para>
+
+<para>The <option>-D</option> option sets a debug verbosity level.  It is
+mainly of interest to developers.</para>
+
+</refsect1>
+<refsect1 id='json_ais'><title>AIS DSV FORMAT</title>
+
+<para>With the <option>-c</option> option, dump lines are values of AIS
+payload fields, pipe-separated, in the order that they occur in the
+payload. Spans of fields expressing a date are emitted as an ISO8601
+timestamp (look for colons and the trailing Z indicating Zulu/UTC
+time), and the 19-bit group of TDMA status fields found at the end of
+message types 1-4 are are dumped as a single unsigned integer (in hex
+preceded by "0x"). Unused regional-authority fields are also dumped
+(in hex preceded by "0x"). Variable-length binary fields are dumped as
+an integer bit length, followed by a colon, followed by a hex
+dump.</para>
+
+</refsect1>
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsdctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+</para>
+</refsect1>
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>Eric S. Raymond <email>esr@thyrsus.com</email>.</para>
+</refsect1>
+
+</refentry>
diff --git a/man/gpsfake.xml b/man/gpsfake.xml
new file mode 100644
index 00000000..e8331d47
--- /dev/null
+++ b/man/gpsfake.xml
@@ -0,0 +1,264 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gpsfake.1'>
+<refentryinfo><date>12 Feb 2005</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpsfake</refentrytitle>
+<manvolnum>1</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpsfake</refname>
+<refpurpose>test harness for gpsd, simulating a GPS</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gpsfake</command>
+      <arg choice='opt'>-1</arg>
+      <arg choice='opt'>-h</arg>
+      <arg choice='opt'>-b</arg>
+      <arg choice='opt'>-c <replaceable>interval</replaceable></arg>
+      <arg choice='opt'>-i</arg>
+      <arg choice='opt'>-D <replaceable>debuglevel</replaceable></arg>
+      <arg choice='opt'>-l</arg>
+      <arg choice='opt'>-m <replaceable>monitor</replaceable></arg>
+      <arg choice='opt'>-g</arg>
+      <arg choice='opt'>-n</arg>
+      <arg choice='opt'>-o <replaceable>options</replaceable></arg>
+      <arg choice='opt'>-p</arg>
+      <arg choice='opt'>-P <replaceable>port</replaceable></arg>
+      <arg choice='opt'>-q</arg>
+      <arg choice='opt'>-r <replaceable>initcmd</replaceable></arg>
+      <arg choice='opt'>-s <replaceable>speed</replaceable></arg>
+      <arg choice='opt'>-S</arg>
+      <arg choice='opt'>-u</arg>
+      <arg choice='opt'>-t</arg>
+      <arg choice='opt'>-T</arg>
+      <arg choice='opt'>-v</arg>
+      <arg rep='repeat'>
+            <arg choice='plain'><replaceable>logfile</replaceable></arg>
+      </arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para><application>gpsfake</application> is a test harness for
+<application>gpsd</application> and its clients.  It opens a pty
+(pseudo-TTY), launches a <application>gpsd</application> instance that
+thinks the slave side of the pty is its GPS device, and repeatedly
+feeds the contents of one or more test logfiles through the master side to the
+GPS. If there are multiple logfiles, sentences from them are
+interleaved in the order the files are specified.</para>
+
+<para><application>gpsfake</application> does not require root
+privileges, and can be run concurrently with a production
+<application>gpsd</application> instance without causing problems.</para>
+
+<para>The logfiles may contain packets in any supported format,
+including in particular NMEA, SiRF, TSIP, or Zodiac.  Leading lines
+beginning with # will be treated as comments and ignored, except in
+the following special cases:</para>
+
+<itemizedlist>
+<listitem><para>
+a comment of the form #Date: yyyy-mm-dd (ISO8601 date format) may be
+used to set the initial date for the log.
+</para></listitem>
+
+<listitem><para>
+a comment of the form #Serial: [0-9]* [78][NOE][12] may be used to set
+serial parameters for the log - baud rate, word length, stop bits.
+</para></listitem>
+
+<listitem><para>
+a comment of the form #Transport: UDP may be used to fake a UDP source
+rather than the normal pty.
+</para></listitem>
+</itemizedlist>
+
+<para>The <application>gpsd</application> instance is run in
+foreground.  The thread sending fake GPS data to the daemon
+is run in background.</para>
+
+</refsect1>
+<refsect1 id='options'><title>OPTIONS</title>
+
+<para>With the -1 option, the logfile is interpreted once only rather
+than repeatedly.  This option is intended to facilitate regression
+testing.</para>
+
+<para>The <option>-b</option> enables a twirling-baton progress indicator
+on standard error.  At termination, it reports elapsed time.</para>
+
+<para>The <option>-c</option> sets the delay between sentences in
+seconds. Fractional values of seconds are legal.  The default is zero
+(no delay).</para>
+
+<para>The <option>-l</option> makes the program dump a line or packet number
+just before each sentence is fed to the daemon. If the sentence is
+textual (e.g. NMEA), the text is dumped as well.  If not, the packet
+will be dumped in hexadecimal (except for RTCM packets, which aren't
+dumped at all).  This option is useful for checking that gpsfake is
+getting packet boundaries right.</para>
+
+<para>The <option>-i</option> is for single-stepping through logfiles.  It dumps
+the line or packet number (and the sentence if the protocol is
+textual) followed by "? ".  Only when the user keys Enter is the line
+actually fed to <application>gpsd</application>.</para>
+
+<para>The <option>-m</option> specifies a monitor program inside which the
+daemon should be run.  This option is intended to be used with
+<citerefentry><refentrytitle>valgrind</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gdb</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+and similar programs.</para>
+
+<para>The <option>-g</option> uses the monitor facility to run the
+<application>gpsd</application> instance within gpsfake under control
+of gdb.</para>
+
+<para>The <option>-o</option> specifies options to pass to the daemon.  The -n
+option passes -n to start the daemon reading the GPS without waiting
+for a client (equivalent to -o "-n").  The <option>-D</option> passes a -D
+option to the daemon: thus -D 4 is shorthand for -o "-D 4".</para>
+
+<para>The -p ("pipe") option sets watcher mode and dumps the NMEA and GPSD
+notifications generated by the log to standard output. This is useful
+for regression-testing.</para>
+
+<para>The -P ("port") option sets the daemon's listening port.</para>
+
+<para>The <option>-q</option> tells gpsfake to suppress normal progress
+output and thus act in a quiet manner.</para>
+
+<para>The <option>-r</option> specifies an initialization command to use in pipe mode.
+The default is <command>?WATCH={"enable":true,"json":true}</command>.</para>
+
+<para>The <option>-s</option> sets the baud rate for the slave tty.  The
+default is 4800.</para>
+
+<para>The option -S tells gpsfake to insert realistic delays in the
+test input rather than trying to stuff it through the daemon as fast
+as possible.  This will make the test(s) run much slower, but avoids
+flaky failures due to machine lode and possible race conditions in
+the pty layer.</para>
+
+<para>The <option>-t</option> forces the test framework to use TCP
+rather than pty devices. Besides being a test of TCP source handling,
+this may be useful for testing from within chroot jails where access
+to pty devices is locked out.</para>
+
+<para>The <option>-T</option> makes <application>gpsfake</application> print
+some system information and then exits.</para>
+
+<para>The <option>-u</option> forces the test framework to use UDP
+rather than pty devices. Besides being a test of UDP source handling,
+this may be useful for testing from within chroot jails where access
+to pty devices is locked out.</para>
+
+<para>The <option>-v</option> enables verbose progress reports to stderr.  It is
+mainly useful for debugging <application>gpsfake</application>
+itself.</para>
+
+<para>The <option>-x</option> dumps packets as
+<application>gpsfake</application> gathers them.  It is mainly useful
+for debugging <application>gpsfake</application> itself.</para>
+
+<para>The <option>-h</option> makes <application>gpsfake</application> print
+a usage message and exit.</para>
+
+<para>The argument must be the name of a file containing the
+data to be cycled at the device. <application>gpsfake</application>
+will print a notification each time it cycles.</para>
+
+<para>Normally, gpsfake creates a pty for each logfile and passes the
+slave side of the device to the daemon.  If the header comment in the
+logfile contains the string "UDP", packets are instead shipped via UDP
+port 5000 to the address 192.168.0.1.255.  You can monitor them with
+this: <command>tcpdump -s0 -n -A -i lo udp and port 5000</command>.</para>
+
+</refsect1>
+<refsect1 id='magic'><title>MAGIC COMMENTS</title>
+
+<para>Certain magic comments in test load headers can change the
+conditions of the test.  These are:</para>
+
+<variablelist>
+<varlistentry>
+<term>Serial:</term>
+<listitem><para>May contain a serial-port setting such as 4800 7N2 -
+baud rate followed by 7 or 8 for byte length, N or O or E for parity
+and 1 or 2 for stop bits. The test is run with those settings on the
+slave port that the daemon sees.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>Transport:</term>
+<listitem><para>Values 'TCP' and 'UDP' force the use of TCP and
+UDP feeds respectively (the default is a pty).</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>Delay-Cookie:</term>
+<listitem><para>Must be followed by two whitespace-separated fields, a
+delimiter character and a numeric delay in seconds. Instead of being
+broken up by packet boundaries, the test load is split on the
+delimiters.  The delay is performed after each feed.  Can be useful
+for imposing write boundaries in the middle of packets.
+</para></listitem>
+</varlistentry>
+</variablelist>
+
+</refsect1>
+<refsect1 id='custom'><title>CUSTOM TESTS</title>
+
+<para><application>gpsfake</application> is a trivial wrapper around a
+Python module, also named gpsfake, that can be used to fully script
+sessions involving a <application>gpsd</application> instance, any
+number of client sessions, and any number of fake GPSes feeding the
+daemon instance with data from specified sentence logs.</para>
+
+<para>Source and embedded documentation for this module is shipped with the
+<application>gpsd</application> development tools.  You can use it to
+torture-test either <application>gpsd</application> itself or any
+<application>gpsd</application>-aware client application.</para>
+
+<para>Logfiles for the use with <application>gpsfake</application> can
+be retrieved using <application>gpspipe</application>,
+<application>gpscat</application>, or
+<application>gpsmon</application> from the gpsd distribution, or any
+other application which is able to create a compatible output.</para>
+
+<para>If <application>gpsfake</application> exits with "Cannot execute
+gpsd: executable not found." the environment variable GPSD_HOME can be
+set to the path where gpsd can be found. (instead of adding that folder
+to the PATH environment variable</para>
+
+</refsect1>
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpspipe</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+<citerefentry><refentrytitle>gpsmon</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>Eric S. Raymond <email>esr@thyrsus.com</email>.</para>
+
+</refsect1>
+
+</refentry>
+
diff --git a/man/gpsinit.xml b/man/gpsinit.xml
new file mode 100644
index 00000000..a3750023
--- /dev/null
+++ b/man/gpsinit.xml
@@ -0,0 +1,170 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gpsinit.8'>
+<refentryinfo><date>18 Jan 2013</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpsinit</refentrytitle>
+<manvolnum>8</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpsinit</refname>
+<refpurpose>initialize CAN kernel modules for GPSD</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gpsinit</command>
+      <arg choice='opt'>-n <replaceable>control</replaceable></arg>
+      <arg choice='opt'>-s <replaceable>speed</replaceable></arg>
+      <arg choice='plain'><replaceable>module_name</replaceable></arg>
+      <arg choice='opt'><replaceable>interface_name</replaceable></arg>
+</cmdsynopsis>
+<cmdsynopsis>
+  <command>gpsinit</command>
+      <arg choice='plain'>-h </arg>
+</cmdsynopsis>
+<cmdsynopsis>
+  <command>gpsinit</command>
+      <arg choice='plain'>-v </arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para><application>gpsinit</application> initializes whatever
+kernel-level modules are needed to enable special non-serial hardware
+to communicate with a gpsd instance.  Note: it will need root permissions
+to load modules and perform other special operations, such as changing
+kernel-interface baudrates.</para>
+
+<para>At present, all modes of this tool are concerned with setting up
+kernel-level interfaces to hardware on a CAN (Control Area Network) speaking
+NMEA2000.</para>
+
+<para>The program accepts the following options:</para>
+<variablelist remap='TP'>
+
+<varlistentry>
+<term>-h</term>
+<listitem>
+<para>Display a brief help text.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-v</term>
+<listitem>
+<para>Display the version of <application>gpsinit</application>.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-n</term>
+<listitem>
+<para>Set the CAN network number. The default is 0.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-s</term>
+<listitem>
+<para>Set the baudrate to be used to communicate over the serial line
+to the CAN hardware. The default is 38400 baud.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+<para>The parameter <parameter>module_name</parameter> is mandatory.  The
+socket CAN driver module <parameter>module_name</parameter>.ko will be
+loaded.  <command>gpsinit</command> recognize the following module
+names:
+
+<variablelist>
+<varlistentry>
+<term>plx_pci</term>
+<term>esd_usb2</term>
+<term>vcan</term>
+<term>slcan</term>
+<listitem>
+<para>
+The parameter <parameter>interface_name</parameter> and <parameter>-s
+<replaceable>speed</replaceable></parameter> can used here.
+</para>
+</listitem>
+</varlistentry>
+<varlistentry><term>beaglebone</term>
+<listitem>
+<para> The dcan module needed for the beaglebone is part of the Linux kernel,
+so no module is loaded in this case.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+</para>
+
+<para>The parameter <parameter>interface_name</parameter> is needed for
+slcan hardware only.  It gives the name of the serial device to which the SL
+CAN hardware is connected. The default is /dev/ttyUSB0.
+</para>
+</refsect1>
+
+<refsect1 id='examples'><title>EXAMPLES</title>
+
+<variablelist>
+<varlistentry>
+<term><command>sudo gpsinit  plx_pci</command></term>
+<listitem>
+<para>Attempt to load the module plx_pci and initialize net 0 for the
+connection to a NMEA2000 network. It will set the baudrate to
+250kBits.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term><command>sudo gpsinit  -n 1 plx_pci</command></term>
+<listitem>
+<para>As above, but use net 1.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term><command>sudo gpsinit  -s 38400 slcan /dev/ttyUSB0</command></term>
+<listitem>
+<para>Attempt to load the module slcan and talk to the hardware at
+38400 baud connected to port /dev/ttyUSB0.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term><command>gpsinit -h </command></term>
+<listitem>
+<para>Display a brief help message.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term><command>gpsinit -v </command></term>
+<listitem>
+<para>Display the version of gpsinit.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+<para>Reinhard Arlt <email>reinhard.arlt@t-online.de</email>.</para>
+</refsect1>
+</refentry>
diff --git a/man/gpsmon.xml b/man/gpsmon.xml
new file mode 100644
index 00000000..f33b5f15
--- /dev/null
+++ b/man/gpsmon.xml
@@ -0,0 +1,428 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010-2019 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gpsmon.1'>
+<refentryinfo><date>17 Feb 2009</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpsmon</refentrytitle>
+<manvolnum>1</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpsmon</refname>
+<refpurpose>real-time GPS packet monitor and control utility</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gpsmon</command>
+      <arg choice='opt'>-L </arg>
+      <arg choice='opt'>-V </arg>
+      <arg choice='opt'>-h </arg>
+      <arg choice='opt'>-n </arg>
+      <arg choice='opt'>-a </arg>
+      <arg choice='opt'>-l <replaceable>logfile</replaceable></arg>
+      <arg choice='opt'>-t <replaceable>driver-prefix</replaceable></arg>
+      <arg choice='opt'>
+	<group>
+	  <arg choice='plain'>
+            <replaceable>server</replaceable>
+            <group>
+	      <replaceable>:port</replaceable>
+              <group><replaceable>:device</replaceable></group>
+            </group>
+          </arg>
+          <arg choice='plain'><replaceable>device</replaceable></arg>
+        </group>
+      </arg>
+      <arg choice='opt'>-D <replaceable>debuglevel</replaceable></arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para><application>gpsmon</application> is a monitor that watches
+packets coming from a GPS and displays them along with diagnostic
+information. It supports commands that can be used to tweak GPS
+settings in various ways; some are device-independent, some vary with
+the GPS chipset type. It will behave sanely, just dumping packets,
+when connected to a GPS type it knows nothing about.</para>
+
+<para><application>gpsmon</application> differs from a navigation
+client in that it mostly dumps raw data from the GPS, with only enough
+data-massaging to allow checks against expected output.  In
+particular, this tool does not do any interpolation or modeling
+to derive climb/sink or error estimates. Nor does it discard
+altitude reports when the fix quality is too low.</para>
+
+<para>Unlike <application>gpsd</application>,
+<application>gpsmon</application> never writes control or probe
+strings to the device unless you explicitly tell it to.  Thus, while
+it will auto-sync to binary packet types, it won't automatically
+recognize a device shipping an extended NMEA protocol as anything
+other than a plain NMEA device. Use the <option>-t</option> option or
+the <command>t</command> to work around this.</para>
+
+<para><application>gpsmon</application> is a designed to run in a
+terminal emulator with a minimum 25x80 size; the non-GUI interface is
+a design choice made to accommodate users operating in constrained
+environments and over telnet or ssh connections.  If run in a larger
+window, the size of the packet-log window will be increased to
+fit.</para>
+
+<para><application>gpsmon</application> accepts an -h option that
+displays a usage message, or a -V option to dump the package
+version and exit.</para>
+
+<para>This program may be run in either of two modes, as a client for
+the <application>gpsd</application> daemon (and its associated control
+socket) or directly connected to a specified serial device.  When run
+with no argument, it attempts to connect to the daemon.  If the
+argument begins with a server:port specification it will also attempt
+to connect to the daemon.  If the argument looks like a bare server
+name it will attempt to connect to a daemon running on the default
+gpsd port on that server.  Only if the device argument contains
+slashes but no colons will it be treated as a serial device for direct
+connection. In direct-connect mode <application>gpsmon</application>
+will hunt for a correct baud rate and lock on to it
+automatically. Possible cases look like this:</para>
+
+<variablelist>
+<varlistentry>
+<term>localhost:/dev/ttyS1</term>
+<listitem><para>Look at the default port of localhost, trying both
+IPv4 and IPv6 and watching output from serial device 1.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>example.com:2317</term>
+<listitem><para>Look at port 2317 on example.com, trying both
+IPv4 and IPv6.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>71.162.241.5:2317:/dev/ttyS3</term>
+<listitem><para>Look at port 2317 at the specified IPv4
+address, collecting data from attached serial device 3.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>[FEDC:BA98:7654:3210:FEDC:BA98:7654:3210]:2317:/dev/ttyS5</term>
+<listitem><para>Look at port 2317 at the specified IPv6
+address, collecting data from attached serial device 5.</para></listitem>
+</varlistentry>
+</variablelist>
+
+<para>Unlike <application>gpsd</application>,
+<application>gpsmon</application> run in direct mode does not do its
+own device probing.  Thus, in particular, if you point it at a
+GPS with a native binary mode that happens to be emitting NMEA, it
+won't identify the actual type unless the device emits a recognizable
+NMEA trigger sentence.  The -t and -i options may help you.</para>
+
+<para>The -F option is only valid in client mode; it specifies a
+control socket to which the program should send device control
+strings.  You must specify a valid pathname of a Unix-domain socket on
+your local filesystem.</para>
+
+<para>The -D option enables packet-getter debugging output and is
+probably only useful to developers of the GPSD code.  Consult the
+packet-getter source code for relevant values.</para>
+
+<para>The -L option lists a table showing which GPS device types
+<application>gpsmon</application> has built-in support for, and which
+generic commands can be applied to which GPS types, and then
+exits. Note that this does not list type-specific commands associated
+with individual GPS types.</para>
+
+<para>The -l option sets up logging to a specified file to start
+immediately on device open.  This may be useful is, for example,
+you want to capture the startup message from a device that displays
+firmware version information there.</para>
+
+<para>The -n option forces gpsmon to request NMEA0183 packets instead of the
+raw datastream from gpsd.</para>
+
+<para>The -t option sets up a fallback type. Give it a string that
+is a distinguishing prefix of exactly one driver type name; this will
+be used for mode, speed, and rate switching if the driver selected
+by the packet type lacks those capabilities.  Most useful when the
+packet type is NMEA but the device is known to have a binary mode,
+such as SiRF binary.</para>
+
+<para>The -a option enables a special debugging mode that does not
+use screen painting.  Packets are dumped normally; any character
+typed suspends packet dumping and brings up a command prompt. This
+feature will mainly be of interest to GPSD developers.</para>
+
+<para>After startup (without -a), the top part of the screen reports
+the contents of several especially interesting packet types.  The
+"PPS" field, if nonempty, is the delta between the last 1PPS top of
+second and the system clock at that time.</para>
+
+<para>The bottom half of the screen is a scrolling hex dump of all
+packets the GPS is issuing.  If the packet type is textual, any
+trailing CR/LF is omitted. Dump lines beginning &gt;&gt;&gt; represent
+control packets sent to the GPS. Lines consisting of "PPS" surrounded
+by dashes, if present, indicate 1PPS and the start of the reporting
+cycle.</para>
+
+</refsect1>
+<refsect1 id='commands'><title>COMMANDS</title>
+
+<para>The following device-independent commands are available while
+<application>gpsmon</application> is running:</para>
+
+<variablelist>
+
+<varlistentry>
+<term>i</term>
+<listitem>
+<para>(Direct mode only.) Enable/disable subtype probing and
+reinitialize the driver. In normal operation,
+<application>gpsmon</application> does not send configuration strings
+to the device (except for wakeup strings needed to get it to send
+data, if any). The command 'i1' causes it to send the same sequence of
+subtype probes that <application>gpsd</application> would.  The
+command 'i0' turns off probing; 'i' alone toggles the bit. In either
+case, the current driver is re-selected; if the probe bit is enabled,
+probes will begin to be issued immediately.</para>
+
+<para>Note that enabling probing might flip the device into another
+mode; in particular, it will flip a SiRF chip into binary mode as if
+you had used the <quote>n</quote> command.  This is due to a
+limitation in the SiRF firmware that we can't fix.</para>
+
+<para>This command will generally do nothing after the first time you
+use it, because the device type will already have been discovered.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>c</term>
+<listitem>
+<para>(Direct mode only.) Change cycle time. Follow it with a number
+interpreted as a cycle time in seconds. Most devices have a fixed
+cycle time of 1 second, so this command may fail with a
+message.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>l</term>
+<listitem>
+<para>Toggle packet logging. If packet logging is on, it will be
+turned off and the log closed.  If it is off, logging to the filename
+following the l will be enabled.  Differs from simply capturing the
+data from the GPS device in that only whole packets are logged.
+The logfile is opened for append, so you can log more than one
+portion of the packet stream and they will be stitched together
+correctly.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>n</term>
+<listitem>
+<para>(Direct mode only.) With an argument of 0, switch device to NMEA
+mode at current speed; with an argument of 1, change to binary
+(native) mode. With no argument, toggle the setting. Will show an
+error if the device doesn't have such modes.</para>
+
+<para>After you switch a dual-protocol GPS to NMEA mode with this
+command, it retains the information about the original type and its
+control capabilities. That is why the device type listed before the
+prompt doesn't change.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>q</term>
+<listitem>
+<para>Quit <application>gpsmon</application>.  Control-C, or whatever
+your current interrupt character is, works as well.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>s</term>
+<listitem>
+<para>(Direct mode only.) Change baud rate. Follow it with a number
+interpreted as bits per second, for example "s9600". The speed number
+may optionally be followed by a colon and a wordlength-parity-stopbits
+specification in the traditional style, e.g 8N1 (the default), 7E1,
+etc.  Some devices don't support serial modes other than their
+default, so this command may fail with a message.</para>
+
+<para>Use this command with caution.  On USB and Bluetooth GPSes it is
+also possible for serial mode setting to fail either because the
+serial adaptor chip does not support non-8N1 modes or because the
+device firmware does not properly synchronize the serial adaptor chip
+with the UART on the GPS chipset when the speed changes. These
+failures can hang your device, possibly requiring a GPS power cycle or (in
+extreme cases) physically disconnecting the NVRAM backup battery.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>t</term>
+<listitem>
+<para>(Direct mode only.) Force a switch of monitoring type. Follow it
+with a string that is unique to the name of a gpsd driver with
+<application>gpsmon</application> support;
+<application>gpsmon</application> will switch to using that driver and
+display code. Will show an error message if there is no matching gpsd
+driver, or multiple matches, or the unique match has no display
+support in <application>gpsmon</application>.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>x</term>
+<listitem>
+<para>(Direct mode only.) Send hex payload to device. Following the
+command letter you may type hex digit pairs; end with a newline.
+These will become the payload of a control packet shipped to the
+device. The packet will be wrapped with headers, trailers, and
+checksum appropriate for the current driver type. The first one or two
+bytes of the payload may be specially interpreted, see the description
+of the <option>-x</option> of
+<citerefentry><refentrytitle>gpsctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>X</term>
+<listitem>
+<para>(Direct mode only.) Send raw hex bytes to device. Following the
+command letter you may type hex digit pairs; end with a newline.
+These will be shipped to the device.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>Ctrl-S</term>
+<listitem>
+<para>Freeze display, suspend scrolling in debug window.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>Ctrl-Q</term>
+<listitem>
+<para>Unfreeze display, resume normal operation.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+<refsect2><title>NMEA support</title>
+
+<para>(These remarks apply to not just generic NMEA devices
+but all extended NMEA devices for which
+<application>gpsmon</application> presently has support.)</para>
+
+<para>All fields are raw data from the GPS except (a) the "Cooked PVT"
+window near top of screen, provided as a check and (b) the "PPS
+offset" field.</para>
+
+<para>There are no device-specific commands. Which generic
+commands are available may vary by type: examine the output
+of <command>gpsmon -l</command> to learn more.</para>
+</refsect2>
+
+<refsect2><title>SiRF support</title>
+<para>Most information is raw from the GPS.  Underlined fields are
+derived by translation from ECEF coordinates or application of
+leap-second and local time-zone offsets. 1PPS is the clock lag as
+usual.</para>
+
+<para>The following commands are supported for SiRF GPSes only:</para>
+
+<variablelist>
+<varlistentry>
+<term>A</term>
+<listitem>
+<para>(Direct mode only.) Toggle reporting of 50BPS subframe data.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>M</term>
+<listitem>
+<para>(Direct mode only.) Set (M1) or clear (M0) static
+navigation. The SiRF documentation says <quote>Static navigation is a
+position filter designed to be used with motor vehicles.  When the
+vehicle's velocity falls below a threshold, the position and heading
+are frozen, and velocity is set to zero. This condition will continue
+until the computed velocity rises above 1.2 times the threshold or
+until the computed position is at least a set distance from the frozen
+place. The threshold velocity and set distance may vary with software
+versions.</quote></para>
+
+<para>Non-static mode is designed for use with road navigation
+software, which often snaps the reported position to the nearest road
+within some uncertainty radius.  You probably want to turn static
+navigation off for pedestrian use, as it is likely to report speed
+zero and position changing in large jumps.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>P</term>
+<listitem>
+<para>(Direct mode only.) Toggle navigation-parameter display mode.
+Toggles between normal display and one that shows selected navigation
+parameters from MID 19, including the Static Navigation bit toggled by
+the 'M' command.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+<para>To interpret what you see, you will need a copy of the
+<citetitle>SiRF Binary Protocol Reference Manual</citetitle>.</para>
+
+</refsect2>
+<refsect2><title>u-blox support</title>
+<para>Most information is raw from the GPS. Underlined fields are
+derived by translation from ECEF coordinates. 1PPS is the clock lag as
+usual. There are no per-type special commands.</para>
+
+</refsect2>
+</refsect1>
+<refsect1 id='bugs'><title>BUGS AND LIMITATIONS</title>
+
+<para>The PPS Offset field will never be updated when running in
+client mode, even if you can see PPS events in the packet window.
+This limitation may be fixed in a future release.</para>
+
+<!--
+Debug window dumps of control message sends to the GPS (preceded
+by '>>>') are only supported for the following drivers: NMEA, SiRF,
+EverMore, Navcom, UBX, TSIP, iTalk, Garmintxt. This feature will not
+work for Zodiacs and not always work for Garmins in binary
+mode.
+-->
+
+</refsect1>
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsdctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpscat</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+<citerefentry><refentrytitle>gpspipe</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>Eric S. Raymond <email>esr@thyrsus.com</email>.</para>
+</refsect1>
+
+</refentry>
+
diff --git a/man/gpspipe.xml b/man/gpspipe.xml
new file mode 100644
index 00000000..9c5da4f3
--- /dev/null
+++ b/man/gpspipe.xml
@@ -0,0 +1,185 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gpspipe.1'>
+ <refentryinfo>
+  <date>17 Jun 2018</date>
+ </refentryinfo>
+ <refmeta>
+  <refentrytitle>gpspipe</refentrytitle>
+  <manvolnum>1</manvolnum>
+  <refmiscinfo class="source">The GPSD Project</refmiscinfo>
+  <refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+ </refmeta>
+ <refnamediv id='name'>
+  <refname>gpspipe</refname>
+  <refpurpose>tool to connect to gpsd and retrieve sentences</refpurpose>
+ </refnamediv>
+ <refsynopsisdiv id='synopsis'>
+  <cmdsynopsis>
+   <command>gpspipe</command>
+   <arg choice='opt'>-2</arg>
+   <arg choice='opt'>-d</arg>
+   <arg choice='opt'>-D <replaceable>debug-level</replaceable>
+   </arg>
+   <arg choice='opt'>-h</arg>
+   <arg choice='opt'>-l</arg>
+   <arg choice='opt'>-n <replaceable>count</replaceable>
+   </arg>
+   <arg choice='opt'>-o <replaceable>filename</replaceable>
+   </arg>
+   <arg choice='opt'>-p</arg>
+   <arg choice='opt'>-r</arg>
+   <arg choice='opt'>-R</arg>
+   <arg choice='opt'>-S</arg>
+   <arg choice='opt'>-s <replaceable>serial-device</replaceable>
+   </arg>
+   <arg choice='opt'>-t</arg>
+   <arg choice='opt'>-T <replaceable>timestamp-format</replaceable>
+   </arg>
+   <arg choice='opt'>-u</arg>
+   <arg choice='opt'>-v</arg>
+   <arg choice='opt'>-w</arg>
+   <arg choice='opt'>-x</arg>
+   <group>
+    <replaceable>server</replaceable>
+    <group>
+     <replaceable>:port</replaceable>
+     <group>
+      <replaceable>:device</replaceable>
+     </group>
+    </group>
+   </group>
+  </cmdsynopsis>
+ </refsynopsisdiv>
+ <refsect1 id='description'>
+  <title>DESCRIPTION</title>
+  <para>
+   <application>gpspipe</application> is a tool to connect
+to <application>gpsd</application> and output the received
+sentences to stdout.  This makes the program useful as a pipe from
+<application>gpsd</application> to another program or file. </para>
+  <para>
+   <application>gpspipe</application> does not require root
+privileges, and can be run concurrently with other tools connecting
+to the local <application>gpsd</application> without causing problems.</para>
+  <para>The output will consist of one or both of the raw NMEA or native
+<application>gpsd</application> sentences.  Each line can be optionally
+time stamped.  There is also an option to exit gracefully after a
+given count of packets.</para>
+  <para>Optionally a server, TCP/IP port number and remote device can be given.
+If omitted, <application>gpspipe</application> connects to localhost on
+the default port (2947) and watches all devices opened by
+<application>gpsd</application>.</para>
+  <para>
+   <application>gpspipe</application> may be run as a daemon, but
+requires the -o flag for writing the output to a file.</para>
+ </refsect1>
+ <refsect1 id='options'>
+  <title>OPTIONS</title>
+  <para>-2 sets the split24 flag on AIS reports. Note: this option
+is experimental and may be changed or removed in a future release.</para>
+  <para>-d causes <application>gpspipe</application> to run as a daemon.</para>
+  <para>-h makes <application>gpspipe</application> print
+a usage message and exit.</para>
+  <para>-l causes <application>gpspipe</application> to sleep for ten
+seconds before attempting to connect to gpsd.  This is very useful
+when running as a daemon, giving gpsd time to start before
+attempting a connection.</para>
+  <para>-n [count] causes [count] sentences to be output.
+<application>gpspipe</application> will then exit gracefully.</para>
+  <para>-o option causes the collected data to be written to the
+specified file.  Use of this option is mandatory
+if <application>gpspipe</application> is run as a daemon.</para>
+  <para>-p enables dumping of profiling information in JSON.</para>
+  <para>-P enables dumping of PPS drift JSON in NMEA and raw modes.</para>
+  <para>-r causes raw NMEA sentences to be output.</para>
+  <para>-R causes super-raw (gps binary) data to be output.  This overrides
+NMEA and gpsd output modes.</para>
+  <para>-s option causes the collected data to be written to the
+specified serial device with settings 4800 8N1.  Thus
+<application>gpspipe</application> can be used with -s and -r options
+to emulate a serial port hardwired to a GPS that
+<application>gpsd</application> is managing.</para>
+  <para>-S sets the scaled flag.</para>
+  <para>-t adds a timestamp to each sentence output.</para>
+  <para>-T sets the format of the timestamp. See
+<citerefentry>
+    <refentrytitle>strftime</refentrytitle>
+    <manvolnum>3</manvolnum>
+   </citerefentry>
+for the available placeholders. Setting this option implies -t.
+Default setting is "%F %T"</para>
+  <para>-u usec resolution time stamp, implies -t. Use -uu to output sec.usec.</para>
+  <para>-v causes <application>gpspipe</application> to show a spinning
+activity indicator on stderr. This is useful if stdout is redirected
+into a file or a pipe. By default the spinner is advanced with every
+messages written; specifying -v more than once will double the number
+of messages required to rotate the spinner.</para>
+  <para>-V prints the version, then exits.</para>
+  <para>-w causes native <application>gpsd</application> sentences to be
+output.</para>
+  <para>-x [seconds] Exit after delay of [seconds].</para>
+  <para>At least one of -R, -r or -w must be specified.</para>
+ </refsect1>
+ <refsect1 id='exampletitle'>
+  <title>EXAMPLES</title>
+  <para>When <application>gpsd</application> is running,
+   <command>gpspipe
+-r -n 100</command> will send one hundred raw NMEA sentences to
+standard output, then exit.</para>
+  <para>When <application>gpsd</application> is running, <command>gpspipe
+-x 5 -w|sed -n '/TPV/{p;q}'</command> will wait at most 5 seconds for a
+TPV message, print it to stdout, then exit.</para>
+ </refsect1>
+ <refsect1 id='see_also'>
+  <title>SEE ALSO</title>
+  <para>
+   <citerefentry>
+    <refentrytitle>gpsd</refentrytitle>
+    <manvolnum>8</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gps</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>libgps</refentrytitle>
+    <manvolnum>3</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>libgpsmm</refentrytitle>
+    <manvolnum>3</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gpsprof</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gpsfake</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gpsctl</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gpscat</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>.
+<citerefentry>
+    <refentrytitle>gpsmon</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>.
+</para>
+ </refsect1>
+ <refsect1 id='maintainer'>
+  <title>AUTHOR</title>
+  <para>Gary E. Miller <email>gem@rellim.com</email>.</para>
+ </refsect1>
+</refentry>
diff --git a/man/gpsprof.xml b/man/gpsprof.xml
new file mode 100644
index 00000000..bdc22691
--- /dev/null
+++ b/man/gpsprof.xml
@@ -0,0 +1,291 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gpsprof.1'>
+<refentryinfo><date>30 May 2018</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpsprof</refentrytitle>
+<manvolnum>1</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpsprof</refname>
+<refpurpose>profile a GPS and gpsd, plotting latency information</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gpsprof</command>
+      <arg choice='opt'>-D <replaceable>debuglevel</replaceable></arg>
+      <arg choice='opt'>-d <replaceable>dumpfile</replaceable></arg>
+      <arg choice='opt'>-f <replaceable>plot_type</replaceable></arg>
+      <arg choice='opt'>-h </arg>
+      <arg choice='opt'>-l <replaceable>logfile</replaceable></arg>
+      <arg choice='opt'>-m <replaceable>threshold</replaceable></arg>
+      <arg choice='opt'>-n <replaceable>samplecount</replaceable></arg>
+      <arg choice='opt'>-r </arg>
+      <arg choice='opt'>-S <replaceable>subtitle</replaceable></arg>
+      <arg choice='opt'>-T <replaceable>terminal</replaceable></arg>
+      <arg choice='opt'>-t <replaceable>title</replaceable></arg>
+      <arg choice='opt'>[server[:port[:device]]]</arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para><application>gpsprof</application> performs accuracy, latency,
+skyview, and time drift profiling on a GPS. It emits to standard output
+a GNUPLOT program that draws one of several illustrative graphs. It can
+also be told to emit the raw profile data.</para>
+
+<para>Information from the default spatial plot it provides can be
+useful for characterizing position accuracy of a GPS.</para>
+
+<para><application>gpsprof</application> uses instrumentation built
+into <application>gpsd</application>.  It can read data from a local
+or remote running <application>gpsd</application>.  Or it can read
+data from a saved logfile.</para>
+
+<para><application>gpsprof</application> is designed to be lightweight
+and use minimal host resources.  No graphics subsystem needs to be
+installed on the host running <application>gpsprof</application>.  Simply
+copy the resultant plot file to another host to be rendered
+with <application>gnuplot</application>.
+</para>
+
+</refsect1>
+<refsect1 id='options'><title>OPTIONS</title>
+
+<para>The -f option sets the plot type.  Currently the following plot
+types are defined:</para>
+
+<variablelist>
+<varlistentry>
+<term>space</term>
+<listitem>
+<para>Generate a scatterplot of fixes and plot probable error circles.
+This data is only meaningful if the GPS is held stationary while
+<application>gpsprof</application> is running.  Various statistics about
+the fixes are listed at the bottom.  This is the default plot type.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>polar</term>
+<listitem>
+<para>Generate a heat map of reported satellite Signal to Noise Ratio
+(SNR) using polar coordinates.  A colored dot is plotted for
+each satellite seen by the GPS.  The color of dot corresponds to the
+SNR of the satellite.  The dots are plotted by azimuth and
+elevation.  North, azimuth 0 degrees, is at the top of the plot.
+Directly overhead, elevation of 90 degrees, is plotted at the center.
+Useful for analyzing the quality of the skyview as seen by the GPS.
+</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>polarunused</term>
+<listitem>
+<para>Similar to the polar plot, but only unused satellites
+are plotted.  Useful for seeing which parts of the antenna skyview
+are obstructed, degraded, below the GPS elevation mask, or otherwise
+rejected.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>polarused</term>
+<listitem>
+<para>Similar to the polar plot, but only satellites used to compute
+fixs are plotted.  Useful for seeing which parts of the antenna
+skyview are being used in fixes.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>time</term>
+<listitem>
+<para>Plot delta of system clock (NTP corrected time) against GPS time
+as reported in PPS messages.  The X axis is sample time in seconds
+from the start of the plot.  The Y axis is the system clock delta from
+GPS time.  This plot only works if <application>gpsd</application> was
+built with the timing (latency timing support) configure option
+enabled.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>instrumented</term>
+<listitem>
+<para>Plot instrumented profile.  Plots various components of the total
+latency between the GPS's fix time and when the client receives the
+fix.  This plot only works if <application>gpsd</application> was built
+with the timing (latency timing support) configuration option enabled.
+</para>
+<para>For purposes of the description, below, start-of-reporting-cycle
+(SORC) is when a device's reporting cycle begins. This time is
+detected by watching to see when data availability follows a long
+enough amount of quiet time that we can be sure we've seen the gap at
+the end of the sensor's previous report-transmission cycle. Detecting
+this gap requires a device running at 9600bps or faster.</para>
+
+<para>Similarly, EORC is end-of-reporting-cycle; when the daemon has
+seen the last sentence it needs in the reporting cycle and ready to ship
+a fix to the client.</para>
+
+<para>The components of the instrumented plot are as follows:</para>
+
+<variablelist>
+<varlistentry>
+<term>Fix latency</term>
+<listitem>
+<para>Delta between GPS time and SORC.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>RS232 time</term>
+<listitem>
+<para>RS232 transmission time for data shipped during the cycle
+(computed from character volume and baud rate).</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>Analysis time</term>
+<listitem>
+<para>EORC, minus SORC, minus RS232 time.  The amount of real time the daemon
+spent on computation rather than I/O.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>Reception time</term>
+<listitem>
+<para>Shipping time from
+the daemon to when it was received by <application>gpsprof</application>.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+<para>Because of RS232 buffering effects, the profiler sometimes
+generates reports of ridiculously high latencies right at the
+beginning of a session.  The -m option lets you set a latency
+threshold, in multiples of the cycle time, above which reports are
+discarded.</para>
+
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>uninstrumented</term>
+<listitem>
+<para>Plot total latency without instrumentation.  Useful mainly as a
+check that the instrumentation is not producing significant distortion.
+The X axis is sample time in seconds from the start of the plot.  The Y
+axs is latency in seconds.It only plots times for reports that contain
+fixes; staircase-like artifacts in the plot are created when elapsed
+time from reports without fixes is lumped in.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+
+<para>The -d option dumps the plot data, without attached gnuplot
+code, to a specified file for post-analysis.</para>
+
+<para>The -D sets debug level.</para>
+
+<para>The -h option makes <application>gpsprof</application> print
+a usage message and exit.</para>
+
+<para>The -l option dumps the raw JSON reports collected from the device
+to a specified file.</para>
+
+<para>The -n option sets the number of packets to sample.  The default
+is 100.  Most GPS are configured to emit one fix per second, so 100
+samples would then span 100 seconds.</para>
+
+<para>The -r option replots from a JSON logfile (such as -l produces)
+on standard input. Both -n and -l options are ignored when this
+one is selected.</para>
+
+<para>The -S option sets a text string to be included in the plot
+as a subtitle.  This will be below the title.</para>
+
+<para>The -t option sets a text string to be the plot title.  This
+will replace the default title.</para>
+
+<para>The -T option generates a terminal type setting into the gnuplot
+code.  Typical usage is "-T png", or "-T pngcairo" telling gnuplot to
+write a PNG file.  Without this option gnuplot will call its X11 display
+code.</para>
+<para> Different installations of <application>gnuplot</application> will
+support different terminal types.  Different terminal types may work better
+for you than other ones.  "-T png" will generate PNG images.  Use "-T jpeg"
+to generate JPEG images.  "-T pngcairo" often works best, but is not
+supported by some distributions.</para>
+
+</refsect1>
+<refsect1 id='signals'><title>SIGNALS</title>
+<para>Sending SIGUSR1 to a running instance causes it to write a
+completion message to standard error and resume processing.  The
+first number in the startup message is the process ID to signal.</para>
+</refsect1>
+
+<refsect1 id='examples'><title>EXAMPLES</title>
+<para>To display the graph, use
+<citerefentry><refentrytitle>gnuplot</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+Thus, for example, to display the default spatial scatter plot, do
+this:
+
+<programlisting>
+gpsprof | gnuplot -persist
+</programlisting>
+</para>
+
+<para>To generate an image file:
+
+<programlisting>
+gpsprof -T png | gnuplot &gt; image.png
+</programlisting>
+</para>
+<para>
+To generate a polar plot, and save the GPS data for further plots:
+<programlisting>
+gpsprof -f polar -T jpeg -l polar.json | gnuplot &gt; polar.png
+</programlisting>
+Then to make the matching polarused and polarunused plots and pngs from
+the just saved the GPS data:
+<programlisting>
+gpsprof -f polarused -T jpeg -r &lt; polar.json &gt; polarused.plot
+gnuplot &lt; polarused.plot &gt; polarused.png
+gpsprof -f polarunused -T jpeg -r &lt; polar.json &gt; polarunused.plot
+gnuplot &lt; polarunused.plot  &gt; polarunused.png
+</programlisting>
+</para>
+
+</refsect1>
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpscat</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gnuplot</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>Eric S. Raymond <email>esr@thyrsus.com</email>.</para>
+
+</refsect1>
+
+</refentry>
+
diff --git a/man/gpsrinex.xml b/man/gpsrinex.xml
new file mode 100644
index 00000000..59632f5a
--- /dev/null
+++ b/man/gpsrinex.xml
@@ -0,0 +1,195 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<!--
+This file is Copyright (c) 2018 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+--><refentry id="gpsrinex.1">
+  <refentryinfo>
+    <date>09 Nov 2018</date>
+  </refentryinfo>
+  <refmeta>
+    <refentrytitle>gpsrinex</refentrytitle>
+    <manvolnum>1</manvolnum>
+    <refmiscinfo class="source">The GPSD Project</refmiscinfo>
+    <refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+  </refmeta>
+  <refnamediv id="name">
+    <refname>gpsrinex</refname>
+    <refpurpose>Read data from gpsd convert to RINEX3 and save to a file.</refpurpose>
+  </refnamediv>
+  <refsynopsisdiv id="synopsis">
+    <cmdsynopsis>
+      <command>gpsrinex</command>
+      <arg choice="opt">-D <replaceable>debuglevel</replaceable></arg>
+      <arg choice="opt">-f <replaceable>filename</replaceable></arg>
+      <arg choice="opt">-h</arg>
+      <arg choice="opt">-i <replaceable>interval</replaceable></arg>
+      <arg choice="opt">-n <replaceable>count</replaceable></arg>
+      <arg choice="opt">-V</arg>
+      <group>
+        <replaceable>server</replaceable>
+        <group>
+          <replaceable>:port</replaceable>
+          <group>
+            <replaceable>:device</replaceable>
+          </group>
+        </group>
+      </group>
+    </cmdsynopsis>
+  </refsynopsisdiv>
+  <refsect1 id="description">
+    <title>DESCRIPTION</title>
+    <para>
+      <application>gpsrinex</application> is a tool to connect to
+<application>gpsd</application> and output the received raw measurements
+as a RINEX 3 observation file.  This is useful for sending raw measurements
+(pseudorange and carrierphase) from <application>gpsd</application> to
+a Precise Point Positioning (PPP) program or service.</para>
+    <para>
+      <application>gpsrinex</application> does not require root
+privileges, and can be run concurrently with other tools connecting
+to a local or remote <application>gpsd</application> without causing
+problems.</para>
+    <para>gpsrinex needs the GPS receiver to be sending raw measurements
+to <application>gpsd</application>.  Only a few GPS have this capability.
+In addition, the <application>gpsd</application> driver for that GPS
+must support raw mode.  Currently only the u-blox driver has this support.
+Only a few u-blox 8 GPS implment the required UBX-RXM-RAWX message.  The
+NEO-M8T is known to work, but requires configuration with
+<application>ubxtool</application>.</para>
+    <para>RINEX has its own definitions and abbreviations.  Be
+sure to consult their documentation.  An observation file (.obs)
+contains data sets, called epochs, that contain the pseudorange
+and carrierphase for each satellite seen.</para>
+    <para>
+      <application>gpsrinex</application> by default will acquire
+20 epochs spaced apart by 30 seconds.  That will take 10 minutes to
+complete.  Most users consider the 30 second interval to be optimal.
+Many PPP programs require at least 1 or 2 hours data, but no more than
+24 or 48 hours of data.  Most users consider 4 to 6 hours of data
+as a minimum for good accuracy.  Additional hours will not yield much
+improvement. </para>
+    <para>The output will consist of one RINEX 3 observation file that
+is ready to be read by your PPP program.  The default filename will be
+in the form: gpsrinexYYYYJJJHHMMSS.obs.  You can override this filename
+with the -f option.</para>
+    <para>Optionally a server, TCP/IP port number and remote device can
+be given.  If omitted, <application>gpsrinex</application> connects to
+localhost on the default port (2947) and watches all devices opened by
+<application>gpsd</application>.</para>
+  </refsect1>
+  <refsect1 id="options">
+    <title>OPTIONS</title>
+    <para>-D [debuglevel]  set debug level to [debuglevel].</para>
+    <para>-f [filename] save RINEX into [filename].</para>
+    <para>-h makes <application>gpsrinex</application> print
+a usage message and exit.</para>
+    <para>-i [interval] wait [interval] seconds between epochs.  OPUS
+accepts intervals of 1, 2, 3, 5, 10, 15 or,30 seconds.  OPUS then
+reduces the data to 30 second intervals.</para>
+    <para>-n [count] causes [count] epochs to be output.  OPUS requires a
+minimum af 15 minutes, and a maximum of 48 hours, of data.</para>
+    <para>-V makes <application>gpsrinex</application> print
+its version and exit.</para>
+  </refsect1>
+  <refsect1 id="exampletitle">
+    <title>EXAMPLES</title>
+    <para>Example 1:</para>
+    <para>Create a 4 hour .obs file.  With a running
+<application>gpsd</application> accessible on the localhost do all of
+the following, in order.  Order matters.</para>
+    <para>The raw measurement messages are long.  Be sure your serial port
+speed is high enough:
+<programlisting>
+gpsctl -s 115200
+</programlisting></para>
+    <para>Disable all NMEA messages, and enable binary messages:
+<programlisting>
+ubxtool -d NMEA
+ubxtool -e BINARY
+</programlisting></para>
+    <para>The NEO-M8N will only reliably output raw measurements
+when only the GPS and QZSS constellations are enabled.
+<application>ubxtool</application>, as recommended by u-blox, enables
+the QZSS constellation in tandem with GPS.  Disable all constellations,
+except GPS (and QZSS):
+
+<programlisting>
+ubxtool -d GLONASS
+ubxtool -d BEIDOU
+ubxtool -d GALILEO
+ubxtool -d SBAS
+ubxtool -e GPS
+</programlisting></para>
+    <para>Verify the constellations enabled:
+<programlisting>
+ubxtool -p GNSS
+</programlisting></para>
+    <para>Enable the good stuff, the raw measurement messages:
+<programlisting>
+ubxtool -e RAWX
+</programlisting></para>
+    <para>Verify raw data messages are being sent:
+<programlisting>
+ubxtool | fgrep RAWX
+</programlisting>
+You should see this output:
+<programlisting>
+UBX-RXM-RAWX:
+UBX-RXM-RAWX:
+</programlisting></para>
+    <para>Collect 4 hours of samples at 30 second intervals, save then
+RINEX 3 observations in the file today.obs:
+<programlisting>
+gpsrinex -i 30 -n 480 -f today.obs
+</programlisting></para>
+    <para>Wait 4 hours.  Enjoy a meal, or do some exercise.  When 
+<application>gpsrinex</application> finishes, upload the file today.obs
+to your favorite PPP service.</para>
+    <para>Example 2:</para>
+    <para>Collect raw masurement data from a remote gpsd.  The
+process it later with <application>gpsrinex</application> and
+<application>gpsprof</application>.</para>
+    <para>Ensure the GPS is configured properly, as shown in Example 1.</para>
+    <para>Grab 4 hours of raw live data from remote
+<application>gpsd</application> at 10.168.1.2:
+<programlisting>
+gpspipe -x 14400 -R 10.168.1.2 > 4h-raw.ubx
+</programlisting></para>
+    <para>When <application>gpspipe</application> is complete, feed the
+data to <application>gpsfake</application>:
+<programlisting>
+gpsfake -1 -P 3000 4h-raw.ubx
+</programlisting></para>
+    <para>In another window, feed the data to 
+<application>gpsrinex</application>.  Use -n 10000000 so that
+all the data from the raw file is used::
+<programlisting>
+gpsrinex -i 30 -n 1000000
+</programlisting></para>
+    <para>Repeat the process with 
+<application>gpsfake</application> to send the data to 
+<application>gpsprof</application>.</para>
+  </refsect1>
+  <refsect1 id="see_also">
+    <title>SEE ALSO</title>
+    <para>One service known to work with obsrinex output is at:
+https://webapp.geod.nrcan.gc.ca/geod/tools-outils/ppp.php</para>
+    <para>OPUS requires 2 frequency observation files.
+https://www.ngs.noaa.gov/OPUS/</para>
+    <para>The curious can find the RINEX 3.03 format described here:
+ftp://igs.org/pub/data/format/rinex303_update1.pdf</para>
+    <para>
+      <citerefentry>
+        <refentrytitle>gpsd</refentrytitle>
+        <manvolnum>8</manvolnum>
+      </citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>ubxtool</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+  </refsect1>
+  <refsect1 id="maintainer">
+    <title>AUTHOR</title>
+    <para>Gary E. Miller <email>gem@rellim.com</email>.</para>
+  </refsect1>
+</refentry>
diff --git a/man/gpxlogger.xml b/man/gpxlogger.xml
new file mode 100644
index 00000000..7d429941
--- /dev/null
+++ b/man/gpxlogger.xml
@@ -0,0 +1,149 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2017 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='gpxlogger.1'>
+<refentryinfo><date>05 Mar 2017</date></refentryinfo>
+<refmeta>
+<refentrytitle>gpxlogger</refentrytitle>
+<manvolnum>1</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>gpxlogger</refname>
+<refpurpose>Tool to connect to gpsd and generate a GPX file</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>gpxlogger</command>
+      <arg choice='opt'>-D <replaceable>debug-level</replaceable></arg>
+      <arg choice='opt'>-d </arg>
+      <arg choice='opt'>-e <replaceable>export-method</replaceable></arg>
+      <arg choice='opt'>-f <replaceable>filename</replaceable></arg>
+      <arg choice='opt'>-l </arg>
+      <arg choice='opt'>-m <replaceable>minmove</replaceable></arg>
+      <arg choice='opt'>-h </arg>
+      <arg choice='opt'>-V </arg>
+      <arg choice='opt'>-i <replaceable>track timeout</replaceable></arg>
+      <group>
+	<replaceable>server</replaceable>
+	  <group>
+	    <replaceable>:port</replaceable>
+	      <group><replaceable>:device</replaceable></group>
+	  </group>
+      </group>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+<para>This program collects fixes from <application>gpsd</application>
+and logs them to standard output in GPX, an XML profile for track
+logging.</para>
+
+<para>The output may be composed of multiple tracks. A new track is
+created if there's no fix written for an interval specified by the
+<option>-i</option> and defaulting to 5 seconds.</para>
+
+<para><application>gpxlogger</application> can use any of the
+export methods that <application>gpsd</application> supports.
+For a list of these methods, use the <option>-l</option>.
+To force the method, give the <option>-e</option> one of
+the colon-terminated method names from the <option>-l</option>
+table.</para>
+</refsect1>
+
+<refsect1 id='options'><title>OPTIONS</title>
+
+<para>The <option>-h</option> option causes <application>gpxlogger</application>
+to emit a summary of its options and then exit.</para>
+
+<para>The <option>-V</option> option causes <application>gpxlogger</application>
+to dump the package version and exit.</para>
+
+<para> The <option>-D</option> option sets a debug level;
+it is primarily for use by GPSD developers.
+It enables various progress messages to standard error.</para>
+
+<para>The <option>-d</option> option tells
+<application>gpxlogger</application> to run as a daemon in background.
+It requires the <option>-f</option> option, which directs output to a
+specified logfile.</para>
+
+<para>The <option>-m</option> option sets a minimum move distance in
+meters (it may include a fractional decimal part).  Motions shorter
+than this will not be logged.</para>
+
+<para>The <option>-r</option> option tells
+<application>gpxlogger</application> to retry when GPSd loses the fix.
+Without <option>-r</option>, <application>gpxlogger</application>
+would quit in this case.</para>
+
+<para>If D-Bus support is available on the host, GPSD is configured to
+use it, and <command>-e dbus</command> is specified, this program
+listens to DBUS broadcasts from
+<application>gpsd</application> via org.gpsd.fix.</para>
+
+<para>With <command>-e sockets</command>, or if sockets is the method
+defaulted to, you may give a server-port-device specification as
+arguments.</para>
+
+<para>The sockets default is to all devices on the localhost,
+using the default GPSD port 2947. An optional argument to any
+client may specify a server to get data from. A colon-separated suffix
+is taken as a port number. If there is a second colon-separated
+suffix, that is taken as a specific device name to be
+watched. However, if the server specification contains square
+brackets, the part inside them is taken as an IPv6 address and
+port/device suffixes are only parsed after the trailing bracket.
+Possible cases look like this:</para>
+
+<variablelist>
+<varlistentry>
+<term>localhost:/dev/ttyS1</term>
+<listitem><para>Look at the default port of localhost, trying both
+IPv4 and IPv6 and watching output from serial device 1.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>example.com:2317</term>
+<listitem><para>Look at port 2317 on example.com, trying both
+IPv4 and IPv6.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>71.162.241.5:2317:/dev/ttyS3</term>
+<listitem><para>Look at port 2317 at the specified IPv4
+address, collecting data from attached serial device 3.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>[FEDC:BA98:7654:3210:FEDC:BA98:7654:3210]:2317:/dev/ttyS5</term>
+<listitem><para>Look at port 2317 at the specified IPv6
+address, collecting data from attached serial device 5.</para></listitem>
+</varlistentry>
+</variablelist>
+
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+<citerefentry><refentrytitle>gpspipe</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHORS</title>
+
+<para>
+  Amaury Jacquot <email>sxpert@sxpert.org</email> &amp;
+  Petter Reinholdtsen <email>pere@hungry.com</email> &amp;
+  Chris Kuethe <email>chris.kuethe@gmail.com</email>
+</para>
+
+</refsect1>
+
+</refentry>
diff --git a/man/libgps.xml b/man/libgps.xml
new file mode 100644
index 00000000..7e850c3d
--- /dev/null
+++ b/man/libgps.xml
@@ -0,0 +1,393 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
+                   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry>
+<refentryinfo><date>14 Aug 2004</date></refentryinfo>
+<refmeta>
+<refentrytitle>3</refentrytitle>
+<manvolnum>3</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>libgps</refname>
+<refpurpose>C service library for communicating with the GPS daemon</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+<funcsynopsis>
+<funcsynopsisinfo>
+
+C:
+
+#include &lt;gps.h&gt;
+
+</funcsynopsisinfo>
+<funcprototype>
+<funcdef>int <function>gps_open</function></funcdef>
+    <paramdef>char *<parameter>server</parameter></paramdef>
+    <paramdef>char * <parameter>port</parameter></paramdef>
+    <paramdef>struct gps_data_t *<parameter>gpsdata</parameter></paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>int <function>gps_send</function></funcdef>
+    <paramdef>struct gps_data_t *<parameter>gpsdata</parameter></paramdef>
+    <paramdef>char *<parameter>fmt</parameter>...</paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>int <function>gps_read</function></funcdef>
+    <paramdef>struct gps_data_t *<parameter>gpsdata</parameter></paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>bool <function>gps_waiting</function></funcdef>
+    <paramdef>const struct gps_data_t *<parameter>gpsdata</parameter></paramdef>
+    <paramdef>int <parameter>timeout</parameter></paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>char *<function>gps_data</function></funcdef>
+    <paramdef>const struct gps_data_t *<parameter>gpsdata</parameter></paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>int <function>gps_unpack</function></funcdef>
+    <paramdef>char *<parameter>buf</parameter></paramdef>
+    <paramdef>struct gps_data_t *<parameter>gpsdata</parameter></paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>int <function>gps_close</function></funcdef>
+    <paramdef>struct gps_data_t *<parameter>gpsdata</parameter></paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>int <function>gps_stream</function></funcdef>
+    <paramdef>struct gps_data_t *<parameter>gpsdata</parameter></paramdef>
+    <paramdef>unsigned int<parameter>flags</parameter></paramdef>
+    <paramdef>void *<parameter>data</parameter></paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>int <function>gps_mainloop</function></funcdef>
+    <paramdef>struct gps_data_t *<parameter>gpsdata</parameter></paramdef>
+    <paramdef>int <parameter>timeout</parameter></paramdef>
+    <paramdef>void (*<parameter>hook</parameter>)(struct gps_data_t *gpsdata)</paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>const char *<function>gps_errstr</function></funcdef>
+    <paramdef>int <parameter>err</parameter></paramdef>
+</funcprototype>
+<funcsynopsisinfo>
+
+Python:
+
+import gps
+
+session = gps.gps(host="localhost", port="2947")
+
+session.stream(flags=gps.WATCH_JSON)
+
+for report in session:
+    process(report)
+
+del session
+
+</funcsynopsisinfo>
+</funcsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para><emphasis remap='B'>libgps</emphasis> is a service library which
+supports communicating with an instance of the
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum>
+</citerefentry>; link it with the linker option -lgps.</para>
+
+<warning><para>Take care to conditionalize your code on the major and
+minor API version symbols in <filename>gps.h</filename>; ideally,
+force a compilation failure if GPSD_API_MAJOR_VERSION is not a version
+you recognize.  See the GPSD project website for more information on
+the protocol and API changes.</para></warning>
+
+<para>Calling <function>gps_open()</function> initializes a GPS-data
+structure to hold the data collected by the GPS, and sets up access to
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>1</manvolnum>
+</citerefentry>
+via either the socket or shared-memory export. The shared-memory
+export is faster, but does not carry information about device
+activation and deactivation events and will not allow you to monitor
+device packet traffic.</para>
+
+<para><function>gps_open()</function> returns 0 on success, -1 on
+errors and is re-entrant.  errno is set depending on the error
+returned from the socket or shared-memory interface; see
+<filename>gps.h</filename> for values and explanations; also see
+<function>gps_errstr()</function>. The host address may be a DNS name,
+an IPv4 dotted quad, an IPV6 address, or the special value
+<constant>GPSD_SHARED_MEMORY</constant> referring to the
+shared-memory export; the library will do the right thing for any of
+these.</para>
+
+<para><function>gps_close()</function> ends the session and should only be
+called after a successful <function>gps_open()</function>.
+It returns 0 on success, -1 on errors.  The shared-memory interface
+close always returns 0, whereas a socket close can result in an error.
+For a socket close error it will have set an errno from the call to the
+system's <function>close()</function>. </para>
+
+<para><function>gps_send()</function> writes a command to the daemon.
+It does nothing when using the shared-memory export.
+The second argument must be a format string containing elements from
+the command set documented at
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>1</manvolnum>
+</citerefentry>.
+It may have % elements as for
+<citerefentry><refentrytitle>sprintf</refentrytitle><manvolnum>3</manvolnum>
+</citerefentry>,
+which will be filled in from any following arguments.  This function
+returns a -1 if there was a Unix-level write error, otherwise
+0. Please read the LIMITATIONS section for additional information and
+cautions. See <function>gps_stream()</function> as a possible
+alternative.</para>
+
+<para><function>gps_read()</function> accepts a response, or sequence
+of responses, from the daemon and interprets.  This function does
+either a nonblocking read for data from the daemon or a fetch from
+shared memory; it returns a count of bytes read for success, -1 with
+errno set on a Unix-level read error, -1 with errno not set if the
+socket to the daemon has closed or if the shared-memory segment was
+unavailable, and 0 if no data is available.</para>
+
+<para><function>gps_waiting()</function> can be used to check whether
+there is new data from the daemon. The second argument is the maximum
+amount of time to wait (in microseconds) on input before returning.
+It returns true if there is input waiting, false on timeout (no data
+waiting) or error condition. When using the socket export, this
+function is a convenience wrapper around a
+<citerefentry><refentrytitle>select</refentrytitle><manvolnum>2</manvolnum>
+</citerefentry>
+call, and zeros <varname>errno</varname> on entry; you can test
+<varname>errno</varname> after exit to get more information about
+error conditions.  Warning: under the shared-memory interface there is
+a tiny race window between <function>gps_waiting()</function> and a
+following <function>gps_read()</function>; in that context, because the
+latter does not block, it is probably better to write a simple read
+loop.</para>
+
+<para><function>gps_mainloop()</function> enables the provided hook
+function to be continually called whenever there is gpsd data.
+The second argument is the maximum amount of time to wait (in microseconds)
+on input before exiting the loop (and return a value of -1).
+It will also return a negative value on various errors.
+</para>
+
+<para><function>gps_unpack()</function> parses JSON from the argument
+buffer into the target of the session structure pointer argument.
+Included in case your application wishes to manage socket I/O
+itself.</para>
+
+<para><function>gps_data()</function> returns the contents of the
+client data buffer (it returns NULL when using the shared-memory
+export). Use with care; this may fail to be a NUL-terminated string if
+WATCH_RAW is enabled.</para>
+
+<para><function>gps_stream()</function> asks
+<application>gpsd</application> to stream the reports it has at you,
+to be made available when you poll (not available when using the
+shared-memory export). The second argument is a flag mask that sets
+various policy bits; see the list below.  Calling
+<function>gps_stream()</function> more than once with different flag
+masks is allowed.</para>
+
+<variablelist>
+<varlistentry>
+<term>WATCH_DISABLE</term>
+<listitem>
+<para>Disable the reporting modes specified by the other WATCH_ flags.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>WATCH_ENABLE</term>
+<listitem>
+<para>Disable the reporting modes specified by the other WATCH_ flags.
+This is the default.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>WATCH_JSON</term>
+<listitem>
+<para>Enable JSON reporting of data. If WATCH_ENABLE is set, and no
+other WATCH flags are set, this is the default.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>WATCH_NMEA</term>
+<listitem>
+<para>Enable generated pseudo-NMEA reporting on binary devices.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>WATCH_RARE</term>
+<listitem>
+<para>Enable reporting of binary packets in encoded hex.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>WATCH_RAW</term>
+<listitem>
+<para>Enable literal passthrough of binary packets.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>WATCH_SCALED</term>
+<listitem>
+<para>When reporting AIS or Subframe data, scale integer quantities to
+floats if they have a divisor or rendering formula associated with them.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>WATCH_NEWSTYLE</term>
+<listitem>
+<para>Force issuing a JSON initialization and getting new-style
+responses. This is the default. </para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>WATCH_OLDSTYLE</term>
+<listitem>
+<para>Force issuing a W or R command and getting old-style
+responses. Warning: this flag (and the capability) will be removed
+in a future release.</para>
+</listitem>
+</varlistentry>
+<varlistentry>
+<term>WATCH_DEVICE</term>
+<listitem>
+<para>Restrict watching to a specified device, path given as second
+argument.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+<para><function>gps_errstr()</function> returns an ASCII string (in
+English) describing the error indicated by a nonzero return value from
+<function>gps_open()</function>.</para>
+
+<para>Consult <filename>gps.h</filename> to learn more about the data
+members and associated timestamps.  Note that information will
+accumulate in the session structure over time, and the 'valid' field
+is not automatically zeroed by each <function>gps_read()</function>.
+It is up to the client to zero that field when appropriate and to keep
+an eye on the fix and sentence timestamps.</para>
+
+<para>The Python implementation supports the same facilities as the
+socket-export calls in the C library; there is no shared-memory
+interface. <function>gps_open()</function> is replaced by the
+initialization of a gps session object; the other calls are methods of
+that object, and have the same names as the corresponding C functions.
+However, it is simpler just to use the session object as an iterator,
+as in the example given below.  Resources within the session object
+will be properly released when it is garbage-collected.</para>
+</refsect1>
+
+<refsect1 id='environment'><title>ENVIRONMENT VARIABLES</title>
+
+<para>By setting the environment variable <envar>GPSD_SHM_KEY</envar>,
+you can control the key value used to create shared-memory segment
+used for communication with <application>gpsd</application>.  This
+will be useful mainly when isolating test instances of
+<application>gpsd</application> from production ones.</para>
+
+</refsect1>
+
+<refsect1 id='example'><title>CODE EXAMPLE</title>
+
+<para>The following is an excerpted and simplified version of the
+libgps interface code from
+<citerefentry><refentrytitle>cgps</refentrytitle><manvolnum>1</manvolnum>
+</citerefentry>.</para>
+
+<programlisting>
+    struct gps_data_t gps_data;
+
+    ret = gps_open(hostName, hostPort, &amp;gps_data);
+
+    (void) gps_stream(&amp;gps_data, WATCH_ENABLE | WATCH_JSON, NULL);
+
+    /* Put this in a loop with a call to a high resolution sleep () in it. */
+    if (gps_waiting (&amp;gps_data, 500)) {
+        errno = 0;
+        if (gps_read (&amp;gps_data) == -1) {
+            ...
+        } else {
+            /* Display data from the GPS receiver. */
+            if (gps_data.set &amp; ...
+        }
+    }
+
+    /* When you are done... */
+    (void) gps_stream(&amp;gps_data, WATCH_DISABLE, NULL);
+    (void) gps_close (&amp;gps_data);
+</programlisting>
+
+</refsect1>
+
+<refsect1 id='limitations'><title>LIMITATIONS</title>
+
+<para>On some systems (those which do not support implicit linking in
+libraries) you may need to add -lm to your link line when you link libgps.
+It is always safe to do this.</para>
+
+<para>In the C API, incautious use of <function>gps_send()</function>
+may lead to subtle bugs. In order to not bloat <structname>struct
+gps_data_t</structname> with space used by responses that are not
+expected to be shipped in close sequence with each other, the storage
+for fields associated with certain responses are combined in a
+union.</para>
+
+<para>The risky set of responses includes VERSION, DEVICELIST, RTCM2,
+RTCM3, SUBFRAME, AIS, GST, and ERROR; it may not be limited to that
+set.  The logic of the daemon's watcher mode is careful to avoid
+dangerous sequences, but you should read and understand the layout of
+<structname>struct gps_data_t</structname> before using
+<function>gps_send()</function> to request any of these
+responses.</para>
+
+</refsect1>
+
+<refsect1 id='compatibility'><title>COMPATIBILITY</title>
+
+<para>The <function>gps_query()</function> supported in major versions
+1 and 2 of this library has been removed.  With the new
+streaming-oriented wire protocol behind this library, it is extremely
+unwise to assume that the first transmission from the daemon after a
+command is shipped to it will be the response to command.</para>
+
+<para>If you must send commands to the daemon explicitly, use
+<function>gps_send()</function> but beware that this ties your code to
+the GPSD wire protocol. It is not recommended.</para>
+
+<para>In earlier versions of the API <function>gps_read()</function> was
+a blocking call and there was a POLL_NONBLOCK option to make it nonblocking.
+<function>gps_waiting()</function> was added to reduce the number of
+wrong ways to code a polling loop.</para>
+
+<para>See the comment above the symbol GPSD_API_MAJOR_VERSION
+in <filename>gps.h</filename> for recent changes.</para>
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum>
+</citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum>
+</citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum>
+</citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='author'><title>AUTHOR</title>
+<para>Eric S. Raymond &lt;esr@thyrsus.com&gt;,
+ C sample code Charles Curley &lt;charlescurley@charlescurley.com&gt;</para>
+</refsect1>
+</refentry>
+
diff --git a/man/libgpsmm.xml b/man/libgpsmm.xml
new file mode 100644
index 00000000..cfcc9d35
--- /dev/null
+++ b/man/libgpsmm.xml
@@ -0,0 +1,83 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
+                   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry>
+<refentryinfo><date>13 May 2005</date></refentryinfo>
+<refmeta>
+<refentrytitle>libgpsmm</refentrytitle>
+<manvolnum>3</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>libgpsmm</refname>
+<refname>libQgpsmm</refname>
+<refpurpose>C++ and QT class wrapper for the GPS daemon</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+<funcsynopsis>
+<funcsynopsisinfo>
+
+C++:
+
+#include &lt;libgpsmm&gt;
+
+</funcsynopsisinfo>
+<funcprototype>
+<funcdef>struct gps_data_t *<function>open</function></funcdef>
+    <paramdef>char *<parameter>host</parameter></paramdef>
+    <paramdef>char *<parameter>port</parameter></paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>struct gps_data_t *<function>open</function></funcdef>
+    <paramdef>void</paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>struct gps_data_t *<function>send</function></funcdef>
+    <paramdef>char *<parameter>request</parameter></paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>struct gps_data_t *<function>read</function></funcdef>
+    <paramdef>void</paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>struct gps_data_t *<function>waiting</function></funcdef>
+    <paramdef>int</paramdef>
+</funcprototype>
+<funcprototype>
+<funcdef>struct gps_data_t *<function>stream</function></funcdef>
+    <paramdef>unsigned int<parameter>flags</parameter></paramdef>
+</funcprototype>
+</funcsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para><emphasis remap='B'>libgpsmm and libQgpsmm</emphasis> are mere wrappers over
+<emphasis remap='B'>libgps</emphasis>. The important difference between the libraries is that libgpsmm is targeted at C++ applications and contained in <emphasis remap='B'>libgps</emphasis>, while libQgpsmm is platform independent by using QTcpSocket to connect to <emphasis remap='B'>gpsd</emphasis> and shipped as an additional library due to the necessary linking to QT.
+Method names are the same as
+the analogue C functions. For a detailed description of the functions
+please read
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+<function>open()</function> must be called after class constructor and before any other method
+(<function>open()</function> is not inside the constructor since it may fail, however constructors have no return value).
+The analogue of the C function <function>gps_close()</function> is in the destructor.</para>
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='author'><title>AUTHOR</title>
+<para>Alfredo Pironti &lt;alfredio@users.sourceforge.net&gt;.</para>
+</refsect1>
+</refentry>
+
diff --git a/man/ntpshmmon.xml b/man/ntpshmmon.xml
new file mode 100644
index 00000000..bcb083a3
--- /dev/null
+++ b/man/ntpshmmon.xml
@@ -0,0 +1,165 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='ntpshmmon.1'>
+<refentryinfo><date>25 Jan 2015</date></refentryinfo>
+<refmeta>
+<refentrytitle>ntpshmmon</refentrytitle>
+<manvolnum>1</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>ntpshmmon</refname>
+<refpurpose>capture samples from GPS or other ntpd refclock sources</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>ntpshmmon</command>
+      <arg choice='opt'>-h </arg>
+      <arg choice='opt'>-n <replaceable>nsamples</replaceable></arg>
+      <arg choice='opt'>-s </arg>
+      <arg choice='opt'>-t <replaceable>seconds</replaceable></arg>
+      <arg choice='opt'>-v </arg>
+      <arg choice='opt'>-V </arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para>This program monitors the shared-memory segments updated by
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+(and possibly other refclock sources) as a way of communicating with
+ntpd, the Network Time Protocol daemon. It reads these in exactly the way an
+ntpd instance does. It can be run concurrently with ntpd without
+interfering with ntpd's normal operation.</para>
+
+<para>This program runs forever, or until a termination option is
+matched, or until interrupted, generating sample reports to standard
+output.  Each line consists of whitespace-separated textual
+fields.</para>
+
+<para>Here is an example of the beginning of a report file:
+
+<screen>
+ntpshmmon version 1
+#      Name   Seen@                Clock                Real               L Prec
+sample NTP2 1424926256.443030206 1424926256.115869233 1424926256.000000000 0  -1
+sample NTP3 1424926256.443060517 1424926255.995430821 1424926256.000000000 0 -20
+sample NTP3 1424926256.995747347 1424926256.995422728 1424926257.000000000 0 -20
+sample NTP2 1424926257.112433572 1424926257.111936726 1424926257.000000000 0  -1
+sample NTP3 1424926257.996221153 1424926257.995410232 1424926258.000000000 0 -20
+sample NTP2 1424926258.107769409 1424926258.107451006 1424926258.000000000 0  -1
+sample NTP3 1424926258.995647636 1424926258.995406476 1424926259.000000000 0 -20
+</screen></para>
+
+<para>The output always begins with a header line expressing the
+version of the output format; the version line begins with "ntpshmmon
+version" and is followed by a numeric version field.</para>
+
+<para>The remainder of the file is either commments or sample lines. A
+comment line begins with a # and should ignored by programs that
+interpret this format.</para>
+
+<para>The fields of a sample line are as follows:
+
+<orderedlist>
+<listitem><para>The keyword "sample"</para></listitem>
+
+<listitem><para>The NTP unit from which it was collected.</para></listitem>
+
+<listitem><para>Collection time of day, seconds.</para></listitem>
+
+<listitem><para>Receiver time of day, seconds.</para></listitem>
+
+<listitem><para>Clock time of day, seconds.</para></listitem>
+
+<listitem><para>Leap-second notification status.</para></listitem>
+
+<listitem><para>Source precision (log(2) of source jitter).</para></listitem>
+</orderedlist>
+</para>
+
+<para>In these fields, "clock time" is the high-precision time
+measured by the source and "receiver time" is Unix UTC time at the
+receiver. It is normal for the seconds part of receiver time to
+coincide with the seconds part of collection time and for the
+nanoseconds part of receiver time to be zero.</para>
+
+<variablelist>
+<varlistentry>
+<term>-v</term>
+<listitem>
+<para>Enable verbose status messages.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-c</term>
+<listitem>
+<para>Device poll interval in fractional seconds - defaults to 1.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-n</term>
+<listitem>
+<para>Set maximum number of samples to collect.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-s</term>
+<listitem>
+<para>Remove all SHM segments used by GPSD. This
+option will normally only be of interest to GPSD developers.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-t</term>
+<listitem>
+<para>Set maximum time to collect samples in seconds.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-h</term>
+<listitem>
+<para>Display program usage and exit.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>-V</term>
+<listitem>
+<para>Display program version and exit.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsdctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>Eric S. Raymond <email>esr@thyrsus.com</email>.</para>
+</refsect1>
+</refentry>
diff --git a/man/ppscheck.xml b/man/ppscheck.xml
new file mode 100644
index 00000000..8a5bdc12
--- /dev/null
+++ b/man/ppscheck.xml
@@ -0,0 +1,103 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2016 by the GPSD project
+SPDX-License-Identifier: BSD-2-clause
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='ppscheck.8'>
+<refentryinfo><date>28 Jul 2016</date></refentryinfo>
+<refmeta>
+<refentrytitle>ppscheck</refentrytitle>
+<manvolnum>8</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>ppscheck</refname>
+<refpurpose>tool to check a serial port for PPS</refpurpose>
+</refnamediv>
+<refsynopsisdiv id='synopsis'>
+
+<cmdsynopsis>
+  <command>ppscheck</command>
+	<arg choice='opt'>-h </arg>
+	<arg choice='opt'>-V </arg>
+ 	<arg choice='plain'><replaceable>device</replaceable></arg>
+</cmdsynopsis>
+</refsynopsisdiv>
+
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para>ppscheck watches a specified serial port for transitions that
+might be PPS.  It looks for changes in handshake lines CD, RI, and CTS
+by running ioctl(...., TIOCMIWAIT, ...) in a loop.  When it sees a state
+change it emits a timestamped line of output dumping the state of the
+handshake signals. It's useful for checking whether a device is emitting
+PPS.</para>
+
+<para>To check the first serial port do this:</para>
+
+<programlisting>
+ppscheck /dev/ttyS0
+</programlisting>
+
+<para>ppscheck is not intended for routine use, but rather for
+diagnostic purposes. Once you have verified a particular device can
+output PPS signals you will never need to use it again on that device.
+</para>
+
+<para>The program accepts the following options:</para>
+<variablelist remap='TP'>
+<varlistentry>
+<term>-h</term>
+<listitem><para>Display help message and terminate.</para></listitem>
+</varlistentry>
+<varlistentry>
+<term>-V</term>
+<listitem>
+<para>Dump version and exit.</para>
+</listitem>
+</varlistentry>
+</variablelist>
+
+<para>The "device" argument should be the pathname of a device. It will
+be the device monitored. </para>
+
+<para>Each output line is the second and nanosecond parts of a timestamp
+followed by the names of the handshake signals then asserted.  Off
+transitions may generate lines with no signals aserted. </para>
+
+<para>If you don't see output within a second, use gpsmon or some other
+equivalent tool to check that your device has a satellite lock and is
+getting 3D fixes before giving up on the possibility of PPS. </para>
+
+<para>Check your cable. Cheap DB9 to DB9 cables such as those issued
+with UPSes often carry TXD/RXD/GND only, omitting handshake lines such
+as DCD.  Suspect this especially if the cable jacket looks too skinny to
+hold more than three leads! </para>
+
+<para>Most GPS that have built in USB do not support PPS.  When in doubt,
+contact the vendor for confirmation that your device does supply PPS.
+</para>
+
+</refsect1>
+
+<refsect1 id='exit_status'><title>RETURN VALUES</title>
+
+<para>1 if the device counld not be opened. 0 otherwise</para>
+
+</refsect1>
+
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>Eric S. Raymond <email>esr@thyrsus.com</email>.</para>
+</refsect1>
+</refentry>
diff --git a/man/srec.xml b/man/srec.xml
new file mode 100644
index 00000000..0e4e5be8
--- /dev/null
+++ b/man/srec.xml
@@ -0,0 +1,308 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2010 by the GPSD project
+BSD terms apply: see the file COPYING in the distribution root for -details.
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='srec.5'>
+<refentryinfo><date>15 Jul 2005</date></refentryinfo>
+<refmeta>
+<refentrytitle>srec</refentrytitle>
+<manvolnum>5</manvolnum>
+<refmiscinfo class="source">The GPSD Project</refmiscinfo>
+<refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+</refmeta>
+<refnamediv id='name'>
+<refname>srec</refname>
+<refpurpose>Motorola S-record record and file format</refpurpose>
+</refnamediv>
+<refsect1 id='description'><title>DESCRIPTION</title>
+
+<para>Motorola S-records are a form of simple ASCII encoding for
+binary data.  This format is commonly used for firmware uploads to
+GPSes, industrial robots, and other kinds of microcontroller-driven
+hardware.  It has several convenient properties, including
+inspectability, easy editing with any text editor, and checksumming
+for verification of transmission across noisy serial lines.</para>
+
+<para>An S-record file consists of a sequence of specially formatted
+ASCII character strings. An S-record will be less than or equal to 78
+bytes in length.</para>
+
+<para>The order of S-records within a file is of no significance and
+no particular order may be assumed.</para>
+
+<para>The general format of an S-record follows:</para>
+
+<screen>
++-------------------//------------------//-----------------------+
+| type | count | address  |            data           | checksum |
++-------------------//------------------//-----------------------+
+</screen>
+
+<variablelist>
+<varlistentry>
+<term>type</term>
+<listitem><para>A char[2] field. These characters
+describe the type of record (S0, S1, S2, S3, S5, S7, S8, or
+S9).</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>count</term>
+<listitem><para>A char[2] field. These characters when paired and
+interpreted as a big-endian hexadecimal integer, display the count of remaining
+character pairs in the record.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>address</term>
+<listitem><para>A char[4,6, or 8] field. These characters grouped and
+interpreted as a big-endian hexadecimal integer, display the address
+at which the data field is to be loaded into memory. The length of the
+field depends on the number of bytes necessary to hold the address. A
+2-byte address uses 4 characters, a 3-byte address uses 6 characters,
+and a 4-byte address uses 8 characters.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>data</term>
+<listitem><para>A char [0-64] field. These characters when paired and
+interpreted as hexadecimal values represent the memory loadable data
+or descriptive information.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>checksum</term>
+<listitem><para>A char[2] field. These characters when paired and
+interpreted as a big-endian hexadecimal integer display the least
+significant byte of the ones complement of the sum of the byte values
+represented by the pairs of characters making up the count, the
+address, and the data fields.</para></listitem>
+</varlistentry>
+</variablelist>
+
+<para>Each record is terminated with a line feed. If any additional or
+different record terminator(s) or delay characters are needed during
+transmission to the target system it is the responsibility of the
+transmitting program to provide them.</para>
+
+<para>There are 9 record types, as follows:</para>
+
+<variablelist>
+<varlistentry>
+<term>S0</term>
+<listitem>
+<para>The type of record is 'S0' (0x5330). The address field
+is unused and will be filled with zeros (0x0000). The header
+information within the data field is divided into the following
+subfields.</para>
+
+<orderedlist>
+<listitem><para>mname is char[20] and is the module name.</para></listitem>
+<listitem><para>ver is char[2] and is the version number.</para></listitem>
+<listitem><para>rev is char[2] and is the revision number.</para></listitem>
+<listitem><para>description is char[0-36] and is a text comment.</para></listitem>
+</orderedlist>
+
+<para>Each of the subfields is composed of ASCII bytes whose
+associated characters, when paired, represent one byte hexadecimal
+values in the case of the version and revision numbers, or represent
+the hexadecimal values of the ASCII characters comprising the module
+name and description.</para>
+</listitem>
+</varlistentry>
+
+<varlistentry>
+<term>S1</term>
+<listitem><para>The type of record field is 'S1' (0x5331). The address
+field is interpreted as a 2-byte big-endian address. The data field is
+composed of memory loadable data.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>S2</term>
+<listitem><para>The type of record field is 'S2' (0x5332). The address
+field is interpreted as a 3-byte big-endian address. The data field is
+composed of memory loadable data.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>S3</term>
+<listitem><para>The type of record field is 'S3' (0x5333). The address
+field is interpreted as a 4-byte big-endian address. The data field is
+composed of memory loadable data.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>S5</term>
+<listitem><para>The type of record field is 'S5' (0x5335). The address
+field is interpreted as a 2-byte big-endian value and contains the
+count of S1, S2, and S3 records previously transmitted. There is no
+data field.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>S7</term>
+<listitem><para>The type of record field is 'S7' (0x5337). The address
+field contains the starting execution address and is interpreted as a
+4-byte big-endian address. There is no data field.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>S8</term>
+<listitem><para>The type of record field is 'S8' (0x5338). The address
+field contains the starting execution address and is interpreted as a
+3-byte big-endian address. There is no data field.</para></listitem>
+</varlistentry>
+
+<varlistentry>
+<term>S9</term>
+<listitem><para>The type of record field is 'S9' (0x5339). The address
+field contains the starting execution address and is interpreted as a
+2-byte big-endian address. There is no data field.</para></listitem>
+</varlistentry>
+</variablelist>
+
+</refsect1>
+<refsect1 id='example'><title>EXAMPLE</title>
+
+<para>Shown below is a typical S-record format file.</para>
+
+<programlisting>
+  S00600004844521B
+  S1130000285F245F2212226A000424290008237C2A
+  S11300100002000800082629001853812341001813
+  S113002041E900084E42234300182342000824A952
+  S107003000144ED492
+  S5030004F8
+  S9030000FC
+</programlisting>
+
+<para>The file consists of one S0 record, four S1 records, one S5
+record and an S9 record.</para>
+
+<para>The S0 record is comprised as follows:</para>
+
+<itemizedlist>
+<listitem><para>S0 S-record type S0, indicating it is a header
+record.</para></listitem>
+
+<listitem><para>06 Hexadecimal 06 (decimal 6), indicating that six
+character pairs (or ASCII bytes) follow.</para></listitem>
+
+<listitem><para>00 00 Four character 2-byte address field, zeroes in
+this example.</para></listitem>
+
+<listitem><para>48 44 52 ASCII H, D, and R - "HDR".</para></listitem>
+
+<listitem><para>1B The checksum.</para></listitem>
+</itemizedlist>
+
+<para> The first S1 record is comprised as follows:</para>
+
+<itemizedlist>
+<listitem><para>S1 S-record type S1, indicating it is a data record to
+be loaded at a 2-byte address.</para></listitem>
+
+<listitem><para>13 Hexadecimal 13 (decimal 19), indicating that
+nineteen character pairs, representing a 2 byte address, 16 bytes of
+binary data, and a 1 byte checksum, follow.  </para></listitem>
+
+<listitem><para>00 00 Four character 2-byte address field; hexidecimal
+address 0x0000, where the data which follows is to be
+loaded.</para></listitem>
+
+<listitem><para>28 5F 24 5F 22 12 22 6A 00 04 24 29 00 08 23 7C
+Sixteen character pairs representing the actual binary data.
+</para></listitem>
+
+<listitem><para>2A The checksum.</para></listitem>
+</itemizedlist>
+
+<para>The second and third S1 records each contain 0x13 (19) character
+pairs and are ended with checksums of 13 and 52, respectively. The
+fourth S1 record contains 07 character pairs and has a checksum of
+92.</para>
+
+<para>The S5 record is comprised as follows:</para>
+
+<itemizedlist>
+<listitem><para>S5 S-record type S5, indicating it is a count record
+indicating the number of S1 records </para></listitem>
+
+<listitem><para>03 Hexadecimal 03 (decimal 3), indicating that three
+character pairs follow.</para></listitem>
+
+<listitem><para>00 04 Hexadecimal 0004 (decimal 4), indicating that
+there are four data records previous to this record.</para></listitem>
+
+<listitem><para>F8 The checksum.</para></listitem>
+</itemizedlist>
+
+
+<para>The S9 record is comprised as follows:</para>
+
+<itemizedlist>
+<listitem><para>S9 S-record type S9, indicating it is a termination
+record.</para></listitem>
+
+<listitem><para>03 Hexadecimal 03 (decimal 3), indicating that three
+character pairs follow.  </para></listitem>
+
+<listitem><para>00 00 The address field, hexadecimal 0 (decimal 0)
+indicating the starting execution address.  </para></listitem>
+
+<listitem><para>FC The checksum.</para></listitem>
+</itemizedlist>
+
+</refsect1>
+<refsect1 id='notes'><title>NOTES</title>
+
+<itemizedlist>
+  <listitem><para> There isn't any evidence that Motorola ever
+    made use of the header information within the data field of the S0
+    record, as described above. This may have been used by some third
+    party vendors.</para></listitem>
+
+<listitem><para>The Unix manual page on S-records is the only place that a
+    78-byte limit on total record length or 64-byte limit on data
+    length is documented. These values shouldn't be trusted for the
+    general case.</para></listitem>
+
+<listitem><para> The count field can have values in the range of 0x3
+    (2 bytes of address + 1 byte checksum = 3, a not very useful
+    record) to 0xff; this is the count of remaining character
+    <emphasis>pairs</emphasis>, including checksum.  </para></listitem>
+
+<listitem><para> If you write code to convert S-Records, you should
+    always assume that a record can be as long as 514 (decimal)
+    characters in length (255 * 2 = 510, plus 4 characters for the
+    type and count fields), plus any terminating character(s).  That
+    is, in establishing an input buffer in C, you would declare it to
+    be an array of 515 chars, thus leaving room for the terminating
+    null character.  </para></listitem>
+</itemizedlist>
+
+</refsect1>
+<refsect1 id='see_also'><title>SEE ALSO</title>
+<para>
+<citerefentry><refentrytitle>gpsd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gps</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgps</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>libgpsmm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+<citerefentry><refentrytitle>gpsfake</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+<citerefentry><refentrytitle>gpsprof</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+</para>
+</refsect1>
+
+<refsect1 id='maintainer'><title>AUTHOR</title>
+
+<para>From an anonymous web page, itself claiming to have been derived
+from an old Unix manual page. Now maintained by the GPSD
+project, which added endianness clarifications.</para>
+
+</refsect1>
+</refentry>
diff --git a/man/ubxtool.xml b/man/ubxtool.xml
new file mode 100644
index 00000000..493f72ab
--- /dev/null
+++ b/man/ubxtool.xml
@@ -0,0 +1,458 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2018 by the GPSD project
+BSD terms apply: see the file COPYING in the distribution root for details.
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='ubxtool.1'>
+ <refentryinfo>
+  <date>24 Sep 2018</date>
+ </refentryinfo>
+ <refmeta>
+  <refentrytitle>ubxtool</refentrytitle>
+  <manvolnum>1</manvolnum>
+  <refmiscinfo class="source">The GPSD Project</refmiscinfo>
+  <refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+ </refmeta>
+ <refnamediv id='name'>
+  <refname>ubxtool</refname>
+  <refpurpose>u-blox tool</refpurpose>
+ </refnamediv>
+ <refsynopsisdiv id='synopsis'>
+  <cmdsynopsis>
+   <command>ubxtool</command>
+   <arg choice='opt'>-? </arg>
+   <arg choice='opt'>-c <replaceable>command</replaceable>
+   </arg>
+   <arg choice='opt'>-d <replaceable>disable</replaceable>
+   </arg>
+   <arg choice='opt'>-e <replaceable>enable</replaceable>
+   </arg>
+   <arg choice='opt'>-f <replaceable>file/device</replaceable>
+   </arg>
+   <arg choice='opt'>-h </arg>
+   <arg choice='opt'>-m <replaceable>mode</replaceable></arg>
+   <arg choice='opt'>-P <replaceable>protver</replaceable></arg>
+   <arg choice='opt'>-p <replaceable>preset</replaceable></arg>
+   <arg choice='opt'>-R <replaceable>rawfile</replaceable></arg>
+   <arg choice='opt'>-r </arg>
+   <arg choice='opt'>-S <replaceable>setspeed</replaceable></arg>
+   <arg choice='opt'>-s <replaceable>speed</replaceable></arg>
+   <arg choice='opt'>-V </arg>
+   <arg choice='opt'>-v <replaceable>verbosity</replaceable></arg>
+   <arg choice='opt'>-w <replaceable>wait</replaceable></arg>
+   <arg choice='opt'>[server[:port[:device]]]</arg>
+  </cmdsynopsis>
+ </refsynopsisdiv>
+ <refsect1 id='description'>
+  <title>DESCRIPTION</title>
+  <para>
+   <application>ubxtool</application> is a tool for u-blox GPS.
+If you do not have a u-blox GPS then can stop reading now.</para>
+  <para>This tool operates with your u-blox GPS at a very low level.
+To understand <application>ubxtool</application> you must first be familiar
+with your u-blox GPS and the documentation for the u-blox binary protocol.
+The u-blox protocol varies greatly depending o GPS model and firmware
+revision.
+</para>
+  <para>
+   <application>ubxtool</application> can decode common u-blox binary
+ messages, poll the GPS status, enable and disable GPS features, and send user
+generated commands to the GPS.  It can read binary messages from a file.  It
+can read and write directly through a serial device, or through a
+running gpsd instance.</para>
+ </refsect1>
+ <refsect1 id='options'>
+  <title>OPTIONS</title>
+  <para>The program accepts the following options:</para>
+  <variablelist remap='TP'>
+   <varlistentry>
+    <term>-c COMMAND</term>
+    <listitem>
+     <para>Send a text string to the GPS.  Accepts one parameter, COMMAND,
+the command string to send to the GPS.  The string is sent verbatim, except
+a newline is appended.
+</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-d OPTION</term>
+    <listitem>
+     <para>Disable an option in the GPS.  Accepts one parameter, OPTION,
+the option to disable.
+</para>
+     <variablelist>
+      <varlistentry>
+       <term>BEIDOU</term>
+       <listitem>
+        <para>Disable use of the BeiDou (COMPASS) constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>BINARY</term>
+       <listitem>
+        <para>Disable sending of the basic binary messages.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>ECEF</term>
+       <listitem>
+        <para>Disable sending of ECEF binary messages.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>GALILEO</term>
+       <listitem>
+        <para>Disable use of the GALILEO constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>GLONASS</term>
+       <listitem>
+        <para>Disable use of the GLONASS constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>GPS</term>
+       <listitem>
+        <para>Disable use of the GPS and QZSS constellations.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>NMEA</term>
+       <listitem>
+        <para>Disable sending basic NMEA messages.  The messages are
+GBS, GGA, GSA, GGL, GST, GSV, RMC, VTG, and ZDA.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>RAWX</term>
+       <listitem>
+        <para>Disable sending of the UBX-RXM-RAWX messages.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>SBAS</term>
+       <listitem>
+        <para>Disable use of the SBAS constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>TMODE2</term>
+       <listitem>
+        <para>Disable sending TMODE2.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>TP</term>
+       <listitem>
+        <para>Disable sending UBX-TIM-TP.</para>
+       </listitem>
+      </varlistentry>
+     </variablelist>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-e OPTION</term>
+    <listitem>
+     <para>Enable an option in the GPS.  Accepts one parameter, OPTION,
+the option to enable.  -e accepts the same OPTIONs as -d, except the action
+is to enable the option.
+</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-f FILE</term>
+    <listitem>
+     <para>Connect to a file or device.  Accepts one parameter, FILE,
+the file or device to open.   Files are opened read-only.  Character
+devices are opened red/write, unless the -r parameter is given.
+</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-h</term>
+    <listitem>
+     <para>Makes <application>ubxtool</application> print
+a usage message and exit.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-m mode</term>
+    <listitem>
+     <para>Sets optional mode parameter to a -p PRESET command.
+</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-P protver</term>
+    <listitem>
+     <para>Sets the protocol version to use for sending commands.  Minimum
+10 (ublox 5).  Maximum 27 (u-blox 9)
+</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-p PRESET</term>
+    <listitem>
+     <para>Send a preset command the GPS.  Accepts one parameter, PRESET,
+the name of the command to send.  <application>ubxtool</application> will exit
+after the GPS acknowledges the command, unless the -W is given.
+</para>
+     <variablelist>
+      <varlistentry>
+       <term>ANT</term>
+       <listitem>
+        <para>Poll the antenna configuration (UBX-CFG-ANT).</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>COLDBOOT</term>
+       <listitem>
+        <para>Coldboot the GPS (UBX-CFG-RST).</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>GNSS</term>
+       <listitem>
+        <para>Poll the enabled constellations (UBX-CFG-GNSS).</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>HOTBOOT</term>
+       <listitem>
+        <para>Hotboot the GPS (UBX-CFG-RST).</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>MODEL</term>
+       <listitem>
+        <para>Configure the Dynamic Platform Model. (UBX-CFG-NAV5).
+</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>NAV5</term>
+       <listitem>
+        <para>Poll the Nav Engines settings (UBX-CFG-NAV6.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>RXM-RAWX</term>
+       <listitem>
+        <para>Poll UBX-RXM-RAWX message.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>RESET</term>
+       <listitem>
+        <para>Reset configuration to defaults (UBX-CFG-CFG).</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>SAVE</term>
+       <listitem>
+        <para>Save current configuration (UBX-CFG-CFG).</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>SVIN</term>
+       <listitem>
+        <para>Poll survey in data (UBX-CFG-SVIN).</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>TMODE2</term>
+       <listitem>
+        <para>Poll Time Mode 2 configuration (UBX-CFG-TMODE2).</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>TP</term>
+       <listitem>
+        <para>Poll time pulse timedata (UBX-TIM-TP).</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>TP5</term>
+       <listitem>
+        <para>Get Time Pulse decodes (UBX-TIM-TP5).</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>VER</term>
+       <listitem>
+        <para>Poll GPS version.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>WARMBOOT</term>
+       <listitem>
+        <para>Warmboot the GPS (UBX-CFG-RST).</para>
+       </listitem>
+      </varlistentry>
+     </variablelist>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-R RAW</term>
+    <listitem>
+     <para>Save all raw data from the GPS into the file RAW.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-r</term>
+    <listitem>
+     <para>Read only.  Do not send anything to the GPS.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-S SPEED</term>
+    <listitem>
+     <para>Set the GPS serial port speed to SPEED bps.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-s SPEED</term>
+    <listitem>
+     <para>Set local serial port speed to SPEED bps. Default 115,200 bps.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-V</term>
+    <listitem>
+     <para>Print <application>ubxtool</application> version and exit.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-v VERBOSITY</term>
+    <listitem>
+     <para>Set verbosity level to VERBOSITY.  Verbosity can be from 0
+     (very quiet), to 4 (very noisy).  Default 2.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-v VERBOSITY</term>
+    <listitem>
+     <para>Set verbosity level to VERBOSITY.  Verbosity can be from 0
+     (very quiet), 2 (decode messages), to 4 (very noisy).  Default 1.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-w WAIT</term>
+    <listitem>
+     <para>Wait for WAIT seconds before exiting.  Will exit early on command
+completion of -d, -e or -p command, unless -W is given.  Default 2.0 second.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-?</term>
+    <listitem>
+     <para>Makes <application>ubxtool</application> print
+a usage message and exit.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>[server[:port[:device]]]</term>
+    <listitem>
+     <para>
+       By default, <application>ubxtool</application> collects data
+       from all compatible devices on localhost, using the default GPSD
+       port 2947. An optional argument may specify a server to get data
+       from. A colon-separated suffix is taken as a port number. If
+       there is a second colon-separated suffix, that is taken as a
+       specific device name to be watched. Further details on the
+<citerefentry>
+       <refentrytitle>gps</refentrytitle>
+       <manvolnum>1</manvolnum>
+      </citerefentry> man page.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+ </refsect1>
+ <refsect1 id='environment'>
+  <title>ENVIRONMENT</title>
+  <para>Options can be placed in the UBXOPTS environment variable.
+UBXOPTS is processed before the CLI options.</para>
+ </refsect1>
+ <refsect1 id='examples'>
+  <title>EXAMPLES</title>
+  <para>
+Decode raw log file:
+<programlisting>
+ubxtool -r -f ublox-neo-m8n.log
+</programlisting>
+  </para>
+  <para>
+Change GPS port speed of device on /dev/ttyAMA0 to 230,400 bps::
+<programlisting>
+ubxtool -S 230400 -f /dev/ttyAMA0
+</programlisting>
+  </para>
+  <para>
+Watch entire GPS reset cycle, include $GPTXT messages:
+<programlisting>
+ubxtool -p COLDBOOT -w 20 -v 2
+</programlisting>
+  </para>
+  <para>
+Poll Enabled Constellations:
+<programlisting>
+ubxtool -p GNSS
+</programlisting>
+Dump gpsd data from remote server:
+<programlisting>
+ubxtool -w 5 server
+</programlisting>
+  </para>
+ </refsect1>
+ <refsect1 id='see_also'>
+  <title>SEE ALSO</title>
+  <para>
+   <application>ubxtool</application> is written to conform to the official
+u-blox documentation for the u-blox binary protocol.
+<ulink url="https://www.u-blox.com/en/product-resources"></ulink></para>
+  <para>
+   <citerefentry>
+    <refentrytitle>gpsd</refentrytitle>
+    <manvolnum>8</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gps</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>cgps</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>xgps</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gpsfake</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gpsctl</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gpscat</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gnuplot</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>.
+</para>
+ </refsect1>
+ <refsect1 id='maintainer'>
+  <title>AUTHOR</title>
+  <para>Gary E. Miller<email>gem@rellim.com</email>
+  </para>
+ </refsect1>
+</refentry>
diff --git a/man/zerk.xml b/man/zerk.xml
new file mode 100644
index 00000000..e82d5c71
--- /dev/null
+++ b/man/zerk.xml
@@ -0,0 +1,468 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!--
+This file is Copyright (c) 2018 by the GPSD project
+BSD terms apply: see the file COPYING in the distribution root for details.
+-->
+<!DOCTYPE refentry PUBLIC
+   "-//OASIS//DTD DocBook XML V4.1.2//EN"
+   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
+<refentry id='zerk.1'>
+ <refentryinfo>
+  <date>18 Sep 2018</date>
+ </refentryinfo>
+ <refmeta>
+  <refentrytitle>zerk</refentrytitle>
+  <manvolnum>1</manvolnum>
+  <refmiscinfo class="source">The GPSD Project</refmiscinfo>
+  <refmiscinfo class="manual">GPSD Documentation</refmiscinfo>
+ </refmeta>
+ <refnamediv id='name'>
+  <refname>zerk</refname>
+  <refpurpose>All purpose GREIS fitting</refpurpose>
+ </refnamediv>
+ <refsynopsisdiv id='synopsis'>
+  <cmdsynopsis>
+   <command>zerk</command>
+   <arg choice='opt'>-? </arg>
+   <arg choice='opt'>-c <replaceable>command</replaceable>
+   </arg>
+   <arg choice='opt'>-d <replaceable>disable</replaceable>
+   </arg>
+   <arg choice='opt'>-e <replaceable>enable</replaceable>
+   </arg>
+   <arg choice='opt'>-f <replaceable>file/device</replaceable>
+   </arg>
+   <arg choice='opt'>-h </arg>
+   <arg choice='opt'>-O <replaceable>oaf</replaceable>
+   </arg>
+   <arg choice='opt'>-p <replaceable>preset</replaceable></arg>
+   <arg choice='opt'>-R <replaceable>rawfile</replaceable>
+   </arg>
+   <arg choice='opt'>-r </arg>
+   <arg choice='opt'>-S <replaceable>setspeed</replaceable>
+   </arg>
+   <arg choice='opt'>-s <replaceable>speed</replaceable>
+   </arg>
+   <arg choice='opt'>-V </arg>
+   <arg choice='opt'>-v <replaceable>verbosity</replaceable>
+   </arg>
+   <arg choice='opt'>-W </arg>
+   <arg choice='opt'>-w <replaceable>wait</replaceable>
+   </arg>
+   <arg choice='opt'>[server[:port[:device]]]</arg>
+  </cmdsynopsis>
+ </refsynopsisdiv>
+ <refsect1 id='description'>
+  <title>DESCRIPTION</title>
+  <para>
+   <application>zerk</application> is an all purpose GREIS fitting.
+If you do not have a Javad GPS that speaks the GREIS protocol then you
+can stop reading now.</para>
+  <para>This tool operates with your Javad GPS at a very low level.
+To understand <application>zerk</application> you must first be familiar
+with your Javad GPS and the documentation for the GREIS protocol.
+<ulink url="http://www.javad.com/downloads/javadgnss/manuals/GREIS/GREIS_Reference_Guide.pdf">GREIS (GNSS Receiver External Interface Specification) Guide</ulink>.
+</para>
+  <para>
+   <application>zerk</application> can decode common GREIS messages,
+poll the GPS status, enable and disable GPS features, and send user
+generated commands to the GPS.  It can read GREIS messages from a file.  It
+can read and write directly through a serial device, or through a
+running gpsd instance.</para>
+ </refsect1>
+ <refsect1 id='options'>
+  <title>OPTIONS</title>
+  <para>The program accepts the following options:</para>
+  <variablelist remap='TP'>
+   <varlistentry>
+    <term>-c COMMAND</term>
+    <listitem>
+     <para>Send a text string to the GPS.  Accepts one parameter, COMMAND,
+the command string to send to the GPS.  The string is sent verbatim, except
+a newline is appended.
+</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-d OPTION</term>
+    <listitem>
+     <para>Disable an option in the GPS.  Accepts one parameter, OPTION,
+the option to disable.  <application>zerk</application> will exit after
+the GPS acknowledges the command, unless the -W is given.
+</para>
+     <variablelist>
+      <varlistentry>
+       <term>4HZ</term>
+       <listitem>
+        <para>Disable basic GREIS messages at 4Hz.  The messages are:
+[RT], [UO], [GT], [PV], [SG], [DP], [SI], [EL], [AZ], [EC], [SS], and
+[ET]</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>COMPASS</term>
+       <listitem>
+        <para>Disable use of the COMPASS (BeiDou) constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>CONS</term>
+       <listitem>
+        <para>Disable use of all constellations.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>DEFMSG</term>
+       <listitem>
+        <para>Disable the default message set (/dev/msg) at 1Hz.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>GALILEO</term>
+       <listitem>
+        <para>Disable use of the GALILEO constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>GLONASS</term>
+       <listitem>
+        <para>Disable use of the GLONASS constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>GPS</term>
+       <listitem>
+        <para>Disable use of the GPS constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>IPR</term>
+       <listitem>
+        <para>Disable all Integer Pseudo Range messages.  These are
+        [rx], [rc], [r1], [r2], [r3], [r5], [rl].</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>IRNSS</term>
+       <listitem>
+        <para>Disable use of the IRNSS constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>NMEA</term>
+       <listitem>
+        <para>Disable basic NMEA 4.1e messages at 4Hz.  The messages are
+GBS, GGA, GSA, GST, GSV, RMC, VTG, and ZDA.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>QZSS</term>
+       <listitem>
+        <para>Disable use of the QZSS constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>SBAS</term>
+       <listitem>
+        <para>Disable use of the SBAS constellation.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>SNR</term>
+       <listitem>
+        <para>Disable all SNR messages, except [EC].  The messages
+disabled are: [E1], [E2], [E3], [E5], [El].</para>
+       </listitem>
+      </varlistentry>
+     </variablelist>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-e OPTION</term>
+    <listitem>
+     <para>Enable an option in the GPS.  Accepts one parameter, OPTION,
+the option to enable.  <application>zerk</application> will exit after
+the GPS acknowledges the command, unless the -W is given.  -e accepts the
+same OPTIONs as -d, except the action is to enable the option.
+</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-f FILE</term>
+    <listitem>
+     <para>Connect to a file or device.  Accepts one parameter, FILE,
+the file or device to open.   Files are opened read-only.  Character
+devices are opened red/write, unless the -r parameter is given.
+</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-h</term>
+    <listitem>
+     <para>Makes <application>zerk</application> print
+a usage message and exit.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-O OAF</term>
+    <listitem>
+     <para>Load an Option Authorization File (OAF) into the GPS.  Accepts
+one parameter, OAF, command file to read.  The OAF is just a special case
+of a .jpo (GREIS command file).  -O will send any valid .jpo file to
+the GPS.
+</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-p PRESET</term>
+    <listitem>
+     <para>Send a preset command the GPS.  Accepts one parameter, PRESET,
+the name of the command to send.  <application>zerk</application> will exit after
+the GPS acknowledges the command, unless the -W is given.
+</para>
+     <variablelist>
+      <varlistentry>
+       <term>COLDBOOT</term>
+       <listitem>
+        <para>Coldboot the GPS.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>CONS</term>
+       <listitem>
+        <para>Poll the enabled constellations.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>DM</term>
+       <listitem>
+        <para>Disable all periodic GREIS messages..</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>ID</term>
+       <listitem>
+        <para>Poll the receiver ID.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>IPR</term>
+       <listitem>
+        <para>Poll all Integer Pseudo Range messages.  These are
+        [rx], [rc], [r1], [r2], [r3], [r5], [rl].</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>OAF</term>
+       <listitem>
+        <para>Poll all OAF options.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>RESET</term>
+       <listitem>
+        <para>Reset (reboot) the GPS.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>SERIAL</term>
+       <listitem>
+        <para>Poll receiver serial number.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>SNR</term>
+       <listitem>
+        <para>Poll all Signal to Noise Ratio (SNR) messages.
+[EC], [E1], [E2], [E3], [E5], [El].</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>VENDOR</term>
+       <listitem>
+        <para>Poll GPS vendor.</para>
+       </listitem>
+      </varlistentry>
+      <varlistentry>
+       <term>VER</term>
+       <listitem>
+        <para>Poll GPS version.</para>
+       </listitem>
+      </varlistentry>
+     </variablelist>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-r</term>
+    <listitem>
+     <para>Read only.  Do not send anything to the GPS.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-R RAW</term>
+    <listitem>
+     <para>Save all raw data from the GPS into the file RAW.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-S SPEED</term>
+    <listitem>
+     <para>Configure the GPS serial speed to SPEED bps.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-s SPEED</term>
+    <listitem>
+     <para>Set local serial port speed to SPEED bps. Default 115,200 bps.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-V</term>
+    <listitem>
+     <para>Print <application>zerk</application> version and exit.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-v VERBOSITY</term>
+    <listitem>
+     <para>Set verbosity level to VERBOSITY.  Verbosity can be from 0
+     (very quiet), to 4 (very noisy).  Default 2.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-v VERBOSITY</term>
+    <listitem>
+     <para>Set verbosity level to VERBOSITY.  Verbosity can be from 0
+     (very quiet), 2 (decode messages), to 4 (very noisy).  Default 1.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-W</term>
+    <listitem>
+     <para>Force waiting the entire wait time.  No early exit for completion
+of -d, -e or -p command.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-w WAIT</term>
+    <listitem>
+     <para>Wait for WAIT seconds before exiting.  Will exit early on command
+completion of -d, -e or -p command, unless -W is given.  Default 2.0 second.</para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>[server[:port[:device]]]</term>
+    <listitem>
+     <para>
+       By default, <application>zerk</application> collects data from all compatible devices on
+       localhost, using the default GPSD port 2947. An optional argument
+       may specify a server to get data from. A
+       colon-separated suffix is taken as a port number. If there is a
+       second colon-separated suffix, that is taken as a specific device
+       name to be watched. Further details on the
+<citerefentry>
+       <refentrytitle>gps</refentrytitle>
+       <manvolnum>1</manvolnum>
+      </citerefentry> man page.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>-?</term>
+    <listitem>
+     <para>Makes <application>zerk</application> print
+a usage message and exit.</para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+ </refsect1>
+ <refsect1 id='environment'>
+  <title>ENVIRONMENT</title>
+  <para>Options can be placed in the ZERKOPTS environment variable.
+ZERKOPTS is processed before the CLI options.</para>
+ </refsect1>
+ <refsect1 id='examples'>
+  <title>EXAMPLES</title>
+  <para>
+Print current Javad serial portC of GPS connected to local running gpsd::
+<programlisting>
+ zerk -c "print,/cur/term"
+</programlisting>
+  </para>
+  <para>
+Decode raw log file:
+<programlisting>
+zerk -r -f greis-binary.log -v 2
+</programlisting>
+  </para>
+  <para>
+Change GPS port speed of device on /dev/ttyAMA0 to 230,400 bps::
+<programlisting>
+zerk -S 230400 -f /dev/ttyAMA0
+</programlisting>
+  </para>
+  <para>
+Watch entire GPS reset cycle:
+<programlisting>
+zerk -p RESET -v 2 -w 20 -W
+</programlisting>
+  </para>
+  <para>
+Poll SVs Status:
+<programlisting>
+zerk -W -w 2 -v 2 -c "out,,jps/{CS,ES,GS,Is,WS,QS}"
+</programlisting>
+Dump gpsd data from remote server:
+<programlisting>
+zerk -v 2 -w 5 server
+</programlisting>
+  </para>
+ </refsect1>
+ <refsect1 id='see_also'>
+  <title>SEE ALSO</title>
+  <para>
+   <application>zerk</application> is written to conform to the official
+Javad documentation for the GREIS protocol.
+<ulink url="http://www.javad.com/downloads/javadgnss/manuals/GREIS/GREIS_Reference_Guide.pdf">GREIS (GNSS Receiver External Interface Specification) Guide</ulink>.
+</para>
+  <para>
+   <citerefentry>
+    <refentrytitle>gpsd</refentrytitle>
+    <manvolnum>8</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gps</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>cgps</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>xgps</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gpsfake</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gpsctl</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gpscat</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>,
+<citerefentry>
+    <refentrytitle>gnuplot</refentrytitle>
+    <manvolnum>1</manvolnum>
+   </citerefentry>.
+</para>
+ </refsect1>
+ <refsect1 id='maintainer'>
+  <title>AUTHOR</title>
+  <para>Gary E. Miller<email>gem@rellim.com</email>
+  </para>
+ </refsect1>
+</refentry>