ubxtool/zerk: install these two programs by default.

1 files changed, 1896 insertions, 0 deletions

diff --git a/zerk b/zerk
new file mode 100755
index 00000000..848d216b
--- /dev/null
+++ b/zerk
@@ -0,0 +1,1896 @@
+#!/usr/bin/env python
+# -*- coding: UTF-8
+'''
+zerk -- GREIS configurator and packet decoder
+
+usage: zerk [OPTIONS] [server[:port[:device]]]
+'''
+
+# This program conforms to the JAVAD document:
+#    GNSS Receiver External Interface Specification
+#    Revised: October 11, 2017
+#
+# Hereafter referred to as "the specification"
+#
+# This file is Copyright (c) 2018 by the GPSD project
+# BSD terms apply: see the file COPYING in the distribution root for details.
+#
+# This code runs compatibly under Python 2 and 3.x for x >= 2.
+# Preserve this property!
+#
+# ENVIRONMENT:
+#    Options in the ZERKOPTS environment variable will be parsed before
+#    the CLI options.  A handy place to put your '-f /dev/ttyXX -s SPEED'
+#
+# example usages:
+#    Coldboot the GPS:          zerk -p COLDBOOT
+#    Print current serial port: zerk -c "print,/cur/term"
+#    Decode raw log file:       zerk -r -f greis-binary.log -v 2
+#    Change GPS port speed:     zerk -S 230400
+#    Watch entire reset cycle:  zerk -p RESET -v 2 -w 20 -W
+#    poll SVs Status:     zerk -W -w 2 -v 2 -c "out,,jps/{CS,ES,GS,Is,WS,QS}"
+#    dump local gpsd data       zerk -v 2 -w 5 localhost
+#
+# TODO: no CRC16 packets handled yet
+# TODO: more packet decodes
+
+from __future__ import absolute_import, print_function, division
+
+import binascii      # for binascii.hexlify()
+import getopt        # for getopt.getopt(), to parse CLI options
+import hashlib       # for hashlib.sha1
+import os            # for os.environ
+import socket        # for socket.error
+import stat          # for stat.S_ISBLK()
+import struct        # for pack()
+import sys
+import time
+import xml.etree.ElementTree  # to parse .jpo files
+
+PROG_NAME = 'zerk'
+
+try:
+    import serial
+except ImportError:
+    # treat serial as special since it is not part of standard Python
+    sys.stderr.write("%s: failed to import pyserial\n" % PROG_NAME)
+    sys.exit(2)
+
+try:
+    import gps
+except ImportError:
+    # PEP8 says local imports last
+    sys.stderr.write("%s: failed to import gps, check PYTHON_PATH\n" %
+                     PROG_NAME)
+    sys.exit(2)
+
+gps_version = '3.18-dev'
+if gps.__version__ != gps_version:
+    sys.stderr.write("%s: ERROR: need gps module version %s, got %s\n" %
+                     (PROG_NAME, gps_version, gps.__version__))
+    sys.exit(1)
+
+
+VERB_QUIET = 0   # quiet
+VERB_NONE = 1    # just output requested data and some info
+VERB_DECODE = 2  # decode all messages
+VERB_INFO = 3    # more info
+VERB_RAW = 4     # raw info
+VERB_PROG = 5    # program trace
+
+# dictionary to hold all user options
+opts = {
+    # command to send to GPS, -c
+    'command': None,
+    # command for -d disable
+    'disable': None,
+    # command for -e enable
+    'enable': None,
+    # default input -f file
+    'input_file_name': None,
+    # default forced wait? -W
+    'input_forced_wait': False,
+    # default port speed -s
+    'input_speed': 115200,
+    # default input wait time -w in seconds
+    'input_wait': 2.0,
+    # the name of an OAF file, extension .jpo
+    'oaf_name': None,
+    # poll command -p
+    'poll': None,
+    # raw log file name
+    'raw_file': None,
+    # open port read only -r
+    'read_only': False,
+    # speed to set GPS -S
+    'set_speed': None,
+    # target gpsd (server:port:device) to connect to
+    'target': {"server": None, "port": gps.GPSD_PORT, "device": None},
+    # verbosity level, -v
+    'verbosity': VERB_NONE,
+    # contents of environment variable ZERKOPTS
+    'progopts': '',
+}
+
+
+class greis(object):
+    """A class for working with the GREIS GPS message formats
+
+    This class contains functions to decode messages in the Javad GREIS
+    "Receiver Input Language" and "Receiver Messages" formats.
+    """
+
+    # when a statement identifier is received, it is stored here
+    last_statement_identifier = None
+    # expected statement identifier.
+    expect_statement_identifier = False
+    # ID of current message as a string
+    s_id = ''
+
+    def __init__(self):
+        "Initialize class"
+
+        self.last_statement_identifier = None
+        self.expect_statement_identifier = False
+        # last epoch received in [~~]
+        # epoch == None means never got epoch, epoch == -1 means missing.
+        self.epoch = None
+
+    def f4_s(self, f):
+        "convert an '! f4' to a string"
+
+        if gps.isfinite(f):
+            # yeah, the precision is a guess
+            return "%.6f" % f
+        return 'X'
+
+    def f8_s(self, f):
+        "convert an '! f8' to a string"
+
+        if gps.isfinite(f):
+            # yeah, the precision is a guess
+            return "%.4f" % f
+        return 'X'
+
+    def i1_s(self, i):
+        "convert an '! i1' to a string"
+        return 'X' if i == 127 else str(i)
+
+    def i2_s(self, i):
+        "convert an '! i2' to a string"
+        return 'X' if i == 32767 else str(i)
+
+    def i4_s(self, i):
+        "convert an '! i4' to a string"
+        return 'X' if i == 2147483647 else str(i)
+
+    def u1_s(self, u):
+        "convert an '! u1' to a string"
+        return 'X' if u == 255 else str(u)
+
+    def u2_s(self, u):
+        "convert an '! u2' to a string"
+        return 'X' if u == 65535 else str(u)
+
+    def u4_s(self, u):
+        "convert an '! u4' to a string"
+        return 'X' if u == 4294967295 else str(u)
+
+    def isuchex(self, c):
+        "Is byte an upper case hex char?"
+        if 48 <= c and 57 >= c:
+            # 0 to 9
+            return int(c) - 48
+        if 65 <= c and 70 >= c:
+            # A to F
+            return int(c) - 55
+        return -1
+
+    soltypes = {0: "None",
+                1: "3D",
+                2: "DGPS",
+                3: "RTK float",
+                4: "RTK fixed",
+                5: "fixed"
+                }
+
+    # allowable speeds
+    speeds = (460800, 230400, 153600, 115200, 57600, 38400, 19200, 9600,
+              4800, 2400, 1200, 600, 300)
+
+    def msg_c_(self, payload):
+        "[c?] decode, Smoothing Corrections"
+
+        s = ' smooth'
+        for i in range(0, len(payload) - 1, 2):
+            u = struct.unpack_from('<h', payload, i)
+            s += " " + self.i2_s(u[0])
+
+        return s + '\n'
+
+    def msg__p(self, payload):
+        "[?p] decode, Integer Relative Carrier Phases"
+
+        s = ' rcp'
+        for i in range(0, len(payload) - 1, 4):
+            u = struct.unpack_from('<l', payload, i)
+            s += " " + self.i4_s(u[0])
+
+        return s + '\n'
+
+    def msg__d(self, payload):
+        "[?d] decode, Relative Doppler"
+
+        s = ' srdp'
+        for i in range(0, len(payload) - 1, 2):
+            u = struct.unpack_from('<h', payload, i)
+            s += " " + self.i2_s(u[0])
+
+        return s + '\n'
+
+    def msg__r(self, payload):
+        "[?r] decode, Integer Relative Pseudo-ranges"
+
+        s = ' srdp'
+        for i in range(0, len(payload) - 1, 2):
+            u = struct.unpack_from('<h', payload, i)
+            s += " " + self.i2_s(u[0])
+
+        return s + '\n'
+
+    def msg__A(self, payload):
+        "[?A] decode, GPS, GALILEO Almanac"
+        m_len = len(payload)
+
+        if ('[EA]' == self.s_id) and (49 > m_len):
+            return " Bad Length %s" % m_len
+
+        u = struct.unpack_from('<BhlBBBfffffffff', payload, 0)
+
+        s = (" sv %u wna %d toa %d healthA %u healthS %u config %u\n"
+             "     af1 %f af0 %f rootA %f ecc %f m0 %f\n"
+             "     omega0 %f argPer %f delf %f omegaDot %f\n" % u)
+
+        if '[EA]' == self.s_id:
+            u = struct.unpack_from('<H', payload, 46)
+            s += ("     iod %d" % (u[0]))
+        return s
+
+    def msg__E(self, payload):
+        "[?E] decode, SNR x 4"
+
+        s = ' cnrX4'
+        for i in range(0, len(payload) - 1, 1):
+            u = struct.unpack_from('<B', payload, i)
+            s += " " + self.u1_s(u[0])
+
+        return s + '\n'
+
+    def msg_WE(self, payload):
+        "[WE] decode, SBAS Ephemeris"
+
+        u = struct.unpack_from('<BBBBLdddffffffffLHB', payload, 0)
+        s = (" waasPrn %u gpsPrn %u iod %u acc %u tod %u\n"
+             "     xg %f yg %f zg %f\n"
+             "     vxg %f vyg %f vzg %f\n"
+             "     vvxg %f vvyg %f vvzg %f\n"
+             "     agf0 %f agf1 %f tow %u wn %u flags %u\n" % u)
+
+        return s
+
+    def msg_r(self, payload):
+        "[r?] decode, Integer Psudeo Ranges"
+
+        s = ' spr'
+        for i in range(0, len(payload) - 1, 4):
+            u = struct.unpack_from('<l', payload, i)
+            s += " " + self.i4_s(u[0])
+
+        return s + '\n'
+
+    def msg_AZ(self, payload):
+        "[AZ] decode, Satellite Azimuths"
+
+        s = " azim"
+        for i in range(0, len(payload) - 1):
+            # azimuth/2, 0 to 180 degrees
+            s += " " + self.u1_s(payload[i])
+
+        return s + '\n'
+
+    def msg_BP(self, payload):
+        "[BP] decode"
+
+        u = struct.unpack_from('<f', payload, 0)
+        return " acc %.3e\n" % u[0]
+
+    def msg_DC(self, payload):
+        "[DC] decode, P/L1 Doppler"
+
+        s = " dp"
+        for i in range(0, len(payload) - 1, 4):
+            u = struct.unpack_from('<L', payload, i)
+            s += " %d" % (u[0])
+
+        return s + '\n'
+
+    def msg_DO(self, payload):
+        "[DO] decode"
+
+        u = struct.unpack_from('<ff', payload, 0)
+        return " val %.3f sval %.3f\n" % u
+
+    def msg_DP(self, payload):
+        "[DP] decode"
+
+        u = struct.unpack_from('<fffBfB', payload, 0)
+        return (" hdop %f vdop %f tdop %f edop %f\n"
+                "     solType %s\n" %
+                (u[0], u[1], u[2], u[4], self.soltypes[u[3]]))
+
+    def msg_E_(self, payload):
+        "[E?] decode, SNR"
+
+        s = ' cnr'
+        for i in range(0, len(payload) - 1):
+            s += " " + self.u1_s(payload[i])
+
+        return s + '\n'
+
+    def msg_ET(self, payload):
+        "[::](ET) decode, Epoch time, end of epoch"
+
+        u = struct.unpack_from('<L', payload, 0)
+        if ((self.epoch is not None and self.epoch != u[0])):
+            if -1 == self.epoch:
+                print("Error: [::](ET) missing [~~](RT)\n")
+            else:
+                print("Error: [::](ET) Wrong Epoch %u, should be %u\n" %
+                      (u[0], self.epoch))
+        # reset epoch
+        self.epoch = -1
+        return "(ET) tod %u\n" % u[0]
+
+    def msg_EL(self, payload):
+        "[EL] decode, Satellite Elevations"
+
+        s = " elev"
+        for i in range(0, len(payload) - 1):
+            # looking for integer (-90 to 90), not byte
+            u = struct.unpack_from('<b', payload, i)
+            s += " " + self.i1_s(u[0])
+
+        return s + '\n'
+
+    def msg_ER(self, payload):
+        "[ER] decode, Error messages"
+
+        parts = payload.split(b'%')
+        if 1 < len(parts):
+            self.last_statement_identifier = parts[1]
+
+        s_payload = "".join(map(chr, payload))
+        print("[ER] %s\n" % s_payload)
+        return " %s\n" % s_payload
+
+    def msg_EU(self, payload):
+        "[EU] decode, GALILEO UTC and GPS Time Parameters"
+
+        u = struct.unpack_from('<dfLHbBHbffLHH', payload, 0)
+        return (" ao %f a1 %f tot %u wnt %u dtls %d dn %u wnlsf %u\n"
+                "     dtlsf %d a0g %f a1g %f t0g %u wn0g %u flags %#x\n" % u)
+
+    def msg_FC(self, payload):
+        "[FC] [F1] [F2] [F3] [f5] [Fl] decode, Signal Lock Loop Flags"
+
+        s = " flags 0x"
+        for i in range(0, len(payload) - 1):
+            u = struct.unpack_from('<H', payload, i)
+            s += " %2x" % (u[0])
+
+        return s + '\n'
+
+    def msg__E1(self, payload):
+        "[?E] decode, BeiDos, GPS, GALILEO, IRNSS Ephemeris "
+        m_len = len(payload)
+        # [GE]
+        if ('[IE]' == self.s_id) and (124 > m_len):
+            return " Bad Length %s" % m_len
+        if ('[CN]' == self.s_id) and (132 > m_len):
+            return " Bad Length %s" % m_len
+        if ('[EN]' == self.s_id) and (145 > m_len):
+            return " Bad Length %s" % m_len
+
+        u = struct.unpack_from('<BLBhlbBhfffflhddddddfffffffff', payload, 0)
+        s = (" sv %u tow %u flags %u iodc %d toc %d ura %d healthS %u\n"
+             "     wn %d tgd %f af2 %f af1 %f af0 %f toe %d\n"
+             "     iode %d rootA %f ecc %f m0 %f omega0 %f\n"
+             "     inc0 %f argPer %f deln %f omegaDot %f\n"
+             "     incDot %f crc %f crs %f cuc %f\n"
+             "     cus %f cic %f cis %f\n" % u)
+
+        if '[EN]' == self.s_id:
+            u = struct.unpack_from('<fffffBB', payload, 122)
+            s += ("     bgdE1E5a %f bgdE1E5b %f aio %f ai1 %f ai2 %f\n"
+                  "     sfi %u navType %u" % u)
+            if 149 <= m_len:
+                # DAf0 added in 3.7.0
+                u = struct.unpack_from('<f', payload, 144)
+                s += (" DAf0 %f" % u)
+            s += '\n'
+
+        if ('[IE]' == self.s_id) and (124 > m_len):
+            u = struct.unpack_from('<B', payload, 122)
+            s += ("     navType %u\n" % u[0])
+
+        if ('[CN]' == self.s_id) and (132 > m_len):
+            u = struct.unpack_from('<fBf', payload, 122)
+            s += ("     tgd2 %f navType %u DAf0 %f\n" % u)
+
+        # TODO: decode length 160 168
+
+        return s
+
+    def msg_GT(self, payload):
+        "[GT] decode, GPS Time "
+
+        u = struct.unpack_from('<LH', payload, 0)
+        return " tow %u wn %d\n" % u
+
+    def msg_ID(self, payload):
+        "[ID] Ionosphere Delays"
+
+        s = ' delay'
+        for i in range(0, len(payload) - 1, 4):
+            u = struct.unpack_from('<f', payload, i)
+            s += " %s" % self.f4_s(u[0])
+
+        return s + '\n'
+
+    def msg_IO(self, payload):
+        "[IO] decode, GPS Ionospheric Parameters"
+
+        u = struct.unpack_from('<LHffffffff', payload, 0)
+
+        return (" tot %d wn %u alpha0 %f alpha1 %f alpha2 %f\n"
+                "     alpha3 %f beta0 %u beta1 %d beta2 %f\n"
+                "     beta3 %f\n" % u)
+
+    def msg_LO(self, payload):
+        "[LO] decode, undocumented message"
+
+        return " Undocumented message\n"
+
+    def msg_MF(self, payload):
+        "[MF] Messages Format"
+
+        u = struct.unpack_from('<BBBBBBB', payload, 0)
+        return (" id %c%c majorVer %c%c minorVer %c%c order %c\n" %
+                (chr(u[0]), chr(u[1]), chr(u[2]), chr(u[3]),
+                 chr(u[4]), chr(u[5]), chr(u[6])))
+
+    def msg_PM(self, payload):
+        "[PM] parameters"
+
+        # PM only seems to work after a coldboot, once
+        # zerk -v 2 -w 20 -c 'out,,jps/{PM}' -W
+        return " %s\n" % payload
+
+    def msg_PV(self, payload):
+        "[PV] decode, Cartesian Position and Velocity"
+
+        u = struct.unpack_from('<dddfffffBB', payload, 0)
+        return (" x %s y %s z %s sigma %s\n"
+                "     vx %s vy %s vz %s\n"
+                "     vsigma %s soltype %s\n" %
+                (self.f8_s(u[0]), self.f8_s(u[1]), self.f8_s(u[2]),
+                 self.f4_s(u[3]), self.f4_s(u[4]), self.f4_s(u[5]),
+                 self.f4_s(u[6]), self.f4_s(u[7]), self.soltypes[u[8]]))
+
+    def msg_RD(self, payload):
+        "[RD] decode, Receiver Date"
+
+        u = struct.unpack_from('<HBBB', payload, 0)
+        return " year %d month %d day %d base %d\n" % u
+
+    def msg_RE(self, payload):
+        "[RE] decode"
+
+        parts = payload.split(b'%')
+        if 1 < len(parts):
+            # Got a statement identifier (ID), save it?
+            # Multiline statement if payload ends with comma or left brace
+            if payload[-1] not in (ord(','), ord('{')):
+                # yes, this is the end
+                self.last_statement_identifier = parts[1]
+
+            # Get the message body
+            part1 = parts[1].split(b',')
+
+            if 'em' == parts[1]:
+                # Probably no parts[2]
+                print("Enable Messages %s" % parts[2])
+                return " Enable Messages %s\n" % parts[2]
+
+            if 'id' == parts[1]:
+                print("ID: %s" % parts[2])
+                return " ID %s\n" % parts[2]
+
+            if 'opts' == part1[0]:
+                if 1 < len(part1):
+                    s = "OAF %s: %s" % (part1[1], parts[2])
+                else:
+                    s = " OAF: %s" % (parts[2])
+                print(s)
+                return " %s\n" % s
+
+            if 'serial' == parts[1]:
+                print("SERIAL: %s" % parts[2])
+                return " SERIAL %s\n" % parts[2]
+
+            if 'vendor' == parts[1]:
+                print("VENDOR: %s" % parts[2])
+                return " Vendor %s\n" % parts[2]
+
+            if 'ver' == parts[1]:
+                print("VER: %s" % parts[2])
+                return " Version %s\n" % parts[2]
+
+            # unknown statement identifier
+            s_payload = "".join(map(chr, payload))
+            print("RE: %s\n" % s_payload)
+
+        return " %s\n" % s_payload
+
+    def msg_RT(self, payload):
+        "[~~](RT) decode, Receiver Time, start of epoch"
+
+        if self.epoch is not None and -1 != self.epoch:
+            print("Error: [~~](RT) missing [::](ET)\n")
+
+        u = struct.unpack_from('<L', payload, 0)
+        # save start of epoch
+        self.epoch = u[0]
+        return "(RT) tod %u\n" % self.epoch
+
+    def msg_S_(self, payload):
+        "[CS], [ES], [GS], [Is], [WS], [NS], [QS], decode, SVs Status"
+
+        # to poll them all: zerk -W -w 2 -v 2 -c "out,,jps/{CS,ES,GS,Is,WS,QS}"
+        # TODO, check @checksum
+
+        return "%s" % payload
+
+    def msg_SE(self, payload):
+        "[SE] decode"
+
+        u = struct.unpack_from('<BBBBB', payload, 0)
+        return " data 0x %x %x %x %x %x\n" % u
+
+    def msg_SG(self, payload):
+        "[SG] decode"
+
+        u = struct.unpack_from('<ffffBB', payload, 0)
+        return (" hpos %s vpos %s hvel %s vvel %s\n"
+                "     soltype %s\n" %
+                (self.f4_s(u[0]), self.f4_s(u[1]), self.f4_s(u[2]),
+                 self.f4_s(u[3]), self.soltypes[u[4]]))
+
+    def msg_SI(self, payload):
+        "[SI] decode, Satellite Index, deprecated by Javad, use [SX]"
+
+        # [SX] require 3.7 firmware, we use [SI] to support 3.6
+        s = " usi"
+        for i in range(0, len(payload) - 1):
+            s += " %d" % payload[i]
+
+        return s + '\n'
+
+    def msg_SP(self, payload):
+        "[SP] decode, Position Covariance Matrix"
+
+        u = struct.unpack_from('<ffffffffffB', payload, 0)
+        return (" xx % f yy % f zz % f tt % f xy % f\n"
+                "     xz % f xt % f yz % f yt % f zt % f\n"
+                "     solType %s\n" %
+                (u[0], u[1], u[2], u[3], u[4],
+                 u[5], u[6], u[7], u[8], u[9],
+                 self.soltypes[u[10]]))
+
+    def msg_SS(self, payload):
+        "[SS] decode, Satellite Navigation Status"
+
+        s = " ns"
+        for i in range(0, len(payload) - 2):
+            s += " %d" % payload[i]
+
+        return (s + '\n     solType %s\n' %
+                self.soltypes[payload[len(payload) - 2]])
+
+    def msg_ST(self, payload):
+        "[ST] decode, Solution Time Tag"
+
+        u = struct.unpack_from('<LBB', payload, 0)
+        return (" time %u ms, soltype %s\n" %
+                (u[0], self.soltypes[u[1]]))
+
+    def msg_SX(self, payload):
+        "[SX] decode, Extended Satellite Indices"
+
+        # [SX] require 3.7 firmware
+        s = " ESI"
+        for i in range(0, len(payload) - 2, 2):
+            u = struct.unpack_from('<BB', payload, i)
+            s += " (%u, %u)" % u
+
+        return s + '\n'
+
+    def msg_TC(self, payload):
+        "[TC] decode, CA/L1 Continous Tracking Time"
+
+        s = " tt"
+        for i in range(0, len(payload) - 1, 2):
+            u = struct.unpack_from('<H', payload, i)
+            s += " %.2f" % u[0]
+
+        return s + '\n'
+
+    def msg_TO(self, payload):
+        "[TO] decode, Reference Time to Receiver Time Offset"
+
+        u = struct.unpack_from('<dd', payload, 0)
+        return " val %.3f sval %.3f\n" % u
+
+    def msg_UO(self, payload):
+        "[UO] decode, GPS UTC Time Parameters"
+
+        u = struct.unpack_from('<dfLHbBHb', payload, 0)
+        return (" a0 %f a1 %f tot %d wnt %d dtls %d\n"
+                "     dn %d wnlsf %d dtlsf %d\n" % u)
+
+    def msg_WA(self, payload):
+        "[WA] decode"
+
+        u = struct.unpack_from('<BBBBLdddfffLH', payload, 0)
+        return (" waasPrn %d gpsPrn %d if %d healthS %d tod %d\n"
+                "     ECEF %.3f %.3f %.3f, %.3f %.3f %.3f\n"
+                "     tow %d wn %d\n" % u)
+
+    def msg_WU(self, payload):
+        "[WU] decode, SBAS UTC Time Parameters"
+
+        u = struct.unpack_from('<dfLHbBHbfbLHB', payload, 0)
+        return (" ao %f a1 %f tot %u wnt %u dtls %d dn %u\n"
+                "wnlsf %u dtlsf %d utcsi %d tow %u wn %u flags %#x\n" % u)
+
+    # table from message id to respective message decoder.
+    # Note: id (%id%) is different than ID (statement identifier)
+    # the id is the first two characters of a GREIS receiver Message
+    # see section 3.3 of the specification
+    messages = {
+        '[0d]': (msg__d, 1),
+        '[1d]': (msg__d, 1),
+        '[1E]': (msg__E, 1),
+        '[1p]': (msg__p, 1),
+        '[1r]': (msg__r, 1),
+        '[2d]': (msg__d, 1),
+        '[2E]': (msg__E, 1),
+        '[2p]': (msg__p, 1),
+        '[2r]': (msg__r, 1),
+        '[3d]': (msg__d, 1),
+        '[3E]': (msg__E, 1),
+        '[3p]': (msg__p, 1),
+        '[3r]': (msg__r, 1),
+        '[5d]': (msg__d, 1),
+        '[5E]': (msg__E, 1),
+        '[5p]': (msg__p, 1),
+        '[5r]': (msg__r, 1),
+        '[AZ]': (msg_AZ, 1),
+        '[BP]': (msg_BP, 5),
+        '[c1]': (msg_c_, 1),
+        '[c2]': (msg_c_, 1),
+        '[c3]': (msg_c_, 1),
+        '[c5]': (msg_c_, 1),
+        '[CA]': (msg__A, 47),
+        '[cc]': (msg_c_, 1),
+        '[CE]': (msg__E, 1),
+        '[cl]': (msg_c_, 1),
+        '[CN]': (msg__E1, 123),
+        '[cp]': (msg__p, 1),
+        '[cr]': (msg__r, 1),
+        '[CS]': (msg_S_, 8),
+        '[DC]': (msg_DC, 1),
+        '[DO]': (msg_DO, 6),
+        '[DP]': (msg_DP, 18),
+        '[E1]': (msg_E_, 1),
+        '[E2]': (msg_E_, 1),
+        '[E3]': (msg_E_, 1),
+        '[E5]': (msg_E_, 1),
+        '[EA]': (msg__A, 47),
+        '[EC]': (msg_E_, 1),
+        '[El]': (msg_E_, 1),
+        '[EL]': (msg_EL, 1),
+        '[EN]': (msg__E1, 123),
+        '[ER]': (msg_ER, 1),
+        '[ES]': (msg_S_, 8),
+        '[EU]': (msg_EU, 40),
+        '[F1]': (msg_FC, 1),
+        '[F2]': (msg_FC, 1),
+        '[F3]': (msg_FC, 1),
+        '[F5]': (msg_FC, 1),
+        '[FA]': (msg_FC, 1),
+        '[FC]': (msg_FC, 1),
+        '[Fl]': (msg_FC, 1),
+        '[GA]': (msg__A, 47),
+        '[GE]': (msg__E1, 123),
+        '[GS]': (msg_S_, 8),
+        '[GT]': (msg_GT, 7),
+        '[IA]': (msg__A, 47),
+        '[ID]': (msg_ID, 1),
+        '[IE]': (msg__E1, 123),
+        '[IO]': (msg_IO, 39),
+        '[Is]': (msg_S_, 8),
+        '[ld]': (msg__d, 1),
+        '[lE]': (msg__E, 1),
+        '[lp]': (msg__p, 1),
+        '[lr]': (msg__r, 1),
+        '[LO]': (msg_LO, 1),
+        '[MF]': (msg_MF, 9),
+        '[::]': (msg_ET, 4),
+        '[~~]': (msg_RT, 4),
+        '[NS]': (msg_S_, 8),
+        '[PM]': (msg_PM, 0),
+        '[PV]': (msg_PV, 46),
+        '[QA]': (msg__A, 47),
+        '[QE]': (msg__E1, 123),
+        '[QS]': (msg_S_, 8),
+        '[r1]': (msg_r, 1),
+        '[r2]': (msg_r, 1),
+        '[r3]': (msg_r, 1),
+        '[r5]': (msg_r, 1),
+        '[rc]': (msg_r, 1),
+        '[RD]': (msg_RD, 6),
+        '[RE]': (msg_RE, 1),
+        '[rl]': (msg_r, 1),
+        '[rx]': (msg_r, 1),
+        '[SE]': (msg_SE, 6),
+        '[SG]': (msg_SG, 18),
+        '[SI]': (msg_SI, 1),
+        '[SP]': (msg_SP, 42),
+        '[SS]': (msg_SS, 1),
+        '[ST]': (msg_ST, 6),
+        '[SX]': (msg_SX, 1),
+        '[TC]': (msg_TC, 1),
+        '[TO]': (msg_TO, 6),
+        '[UO]': (msg_UO, 24),
+        '[WA]': (msg_WA, 51),
+        '[WE]': (msg_WE, 73),
+        '[WS]': (msg_S_, 8),
+        '[WU]': (msg_WU, 40),
+    }
+
+    def decode_msg(self, out):
+        "Decode one message and then return number of chars consumed"
+
+        state = 'BASE'
+        consumed = 0
+        # raw message, sometimes used for checksum calc
+        m_raw = bytearray(0)
+
+        # decode state machine
+        for this_byte in out:
+            consumed += 1
+            if isinstance(this_byte, str):
+                # a character, probably read from a file
+                c = ord(this_byte)
+            else:
+                # a byte, probably read from a serial port
+                c = int(this_byte)
+
+            if VERB_RAW <= opts['verbosity']:
+                if (ord(' ') <= c) and (ord('~') >= c):
+                    # c is printable
+                    print("state: %s char %c (%#x)" % (state, chr(c), c))
+                else:
+                    # c is not printable
+                    print("state: %s char %#x" % (state, c))
+
+            m_raw.extend([c])
+
+            # parse input stream per GREIS Ref Guide Section 3.3.3
+            if 'BASE' == state:
+                # start fresh
+                # place to store 'comments'
+                comment = ''
+                # message id byte one
+                m_id1 = 0
+                # message id byte two
+                m_id2 = 0
+                # message length as integer
+                m_len = 0
+                # byte array to hold payload, including possible checksum
+                m_payload = bytearray(0)
+                m_raw = bytearray(0)
+                m_raw.extend([c])
+
+                if (ord('0') <= c) and (ord('~') >= c):
+                    # maybe id 1, '0' to '~'
+                    state = 'ID1'
+
+                    # start the grab
+                    m_id1 = c
+                    continue
+
+                if ord("%") == c:
+                    # start of %ID%, Receiver Input Language
+                    # per GREIS Ref Guide Section 2.2
+                    state = 'RIL'
+
+                    # start fresh
+                    comment = "%"
+                    continue
+
+                if ord("$") == c:
+                    # NMEA line, treat as comment
+                    state = 'NMEA'
+
+                    # start fresh
+                    comment = "$"
+                    continue
+
+                if ord("#") == c:
+                    # comment line
+                    state = 'COMMENT'
+
+                    # start fresh
+                    comment = "#"
+                    continue
+
+                if ord('\n') == c or ord('\r') == c:
+                    # stray newline or linefeed, eat it
+                    return consumed
+
+                # none of the above, stay in BASE
+                continue
+
+            if state in ('COMMENT', 'JSON', 'RIL'):
+                # inside comment
+                if ord('\n') == c or ord('\r') == c:
+                    # Got newline or linefeed
+                    # GREIS terminates messages on <CR> or <LF>
+                    # Done, got a full message
+                    if b'{"class":"ERROR"' in comment:
+                        # always print gpsd errors
+                        print(comment)
+                    elif VERB_DECODE <= opts['verbosity']:
+                        print(comment)
+                    return consumed
+                else:
+                    comment += chr(c)
+                continue
+
+            if 'ID1' == state:
+                # maybe id 2, '0' to '~'
+                if ord('"') == c:
+                    # technically could be GREIS, but likely JSON
+                    state = 'JSON'
+                    comment += chr(m_id1) + chr(c)
+                elif (ord('0') <= c) and (ord('~') >= c):
+                    state = 'ID2'
+                    m_id2 = c
+                else:
+                    state = 'BASE'
+                continue
+
+            if 'ID2' == state:
+                # maybe len 1, 'A' to 'F'
+                x = self.isuchex(c)
+                if -1 < x:
+                    state = 'LEN1'
+                    m_len = x * 256
+                else:
+                    state = 'BASE'
+                continue
+
+            if 'LEN1' == state:
+                # maybe len 2, 'A' to 'F'
+                x = self.isuchex(c)
+                if -1 < x:
+                    state = 'LEN2'
+                    m_len += x * 16
+                else:
+                    state = 'BASE'
+                continue
+
+            if 'LEN2' == state:
+                # maybe len 3, 'A' to 'F'
+                x = self.isuchex(c)
+                if -1 < x:
+                    state = 'PAYLOAD'
+                    m_len += x
+                else:
+                    state = 'BASE'
+                continue
+
+            if 'NMEA' == state:
+                # inside NMEA
+                if ord('\n') == c or ord('\r') == c:
+                    # Got newline or linefeed
+                    # done, got a full message
+                    # GREIS terminates messages on <CR> or <LF>
+                    if VERB_DECODE <= opts['verbosity']:
+                        print(comment)
+                    return consumed
+                else:
+                    comment += chr(c)
+                continue
+
+            if 'PAYLOAD' == state:
+                # getting payload
+                m_payload.extend([c])
+                if len(m_payload) < m_len:
+                    continue
+
+                # got entire payload
+                self.s_id = "[%c%c]" % (chr(m_id1), chr(m_id2))
+                if VERB_DECODE <= opts['verbosity']:
+                    x_payload = binascii.hexlify(m_payload)
+
+                # [RE], [ER] and more have no 8-bit checksum
+                # assume the rest do
+                if ((self.s_id not in ('[CS]', '[ER]', '[ES]', '[GS]', '[Is]',
+                                       '[MF]', '[NS]', '[PM]', '[QS]', '[RE]',
+                                       '[WS]') and
+                     not self.checksum_OK(m_raw))):
+                    print("ERROR: Bad checksum\n")
+                    if VERB_DECODE <= opts['verbosity']:
+                        print("DECODE: id: %s len: %d\n"
+                              "DECODE: payload: %s\n" %
+                              (self.s_id, m_len, x_payload))
+                    # skip it.
+                    return consumed
+
+                if self.s_id in self.messages:
+                    if VERB_INFO <= opts['verbosity']:
+                        print("INFO: id: %s len: %d\n"
+                              "INFO: payload: %s\n" %
+                              (self.s_id, m_len, x_payload))
+
+                    (decode, length) = self.messages[self.s_id]
+                    if m_len < length:
+                        print("DECODE: %s Bad Length %s\n" %
+                              (self.s_id, m_len))
+                    else:
+                        s = self.s_id + decode(self, m_payload)
+                        if VERB_DECODE <= opts['verbosity']:
+                            print(s)
+                else:
+                    # unknown message
+                    if VERB_DECODE <= opts['verbosity']:
+                        print("DECODE: Unknown: id: %s len: %d\n"
+                              "DECODE: payload: %s\n" %
+                              (self.s_id, m_len, x_payload))
+                return consumed
+
+            # give up
+            state = 'BASE'
+
+        # fell out of loop, no more chars to look at
+        return 0
+
+    def checksum_OK(self, raw_msg):
+        "Check the i8-bit checksum on a message, return True if good"
+
+        # some packets from the GPS use CRC16, some i8-bit checksum, some none
+        # only 8-bit checksum done here for now
+        calc_checksum = self.checksum(raw_msg, len(raw_msg) - 1)
+        rcode = raw_msg[len(raw_msg)-1] == calc_checksum
+        if VERB_RAW <= opts['verbosity']:
+            print("Checksum was %#x, calculated %#x" %
+                  (raw_msg[len(raw_msg)-1], calc_checksum))
+        return rcode
+
+    def _rol(self, value):
+        "rotate a byte left 2 bits"
+        return ((value << 2) | (value >> 6)) & 0x0ff
+
+    def checksum(self, msg, m_len):
+        "Calculate GREIS 8-bit checksum"
+
+        # Calculated per section A.1.1 of the specification
+        # msg may be bytes (incoming messages) or str (outgoing messages)
+
+        ck = 0
+        for c in msg[0:m_len]:
+            if isinstance(c, str):
+                # a string, make a byte
+                c = ord(c)
+            ck = self._rol(ck) ^ c
+
+        return self._rol(ck) & 0x0ff
+
+    def make_pkt(self, m_data):
+        "Build an output message, always ASCII, add checksum and terminator"
+
+        # build core message
+
+        # no leading spaces, checksum includes the @
+        m_data = m_data.lstrip() + b'@'
+
+        chk = self.checksum(m_data, len(m_data))
+
+        # all commands end with CR and/or LF
+        return m_data + (b'%02X' % chk) + b'\n'
+
+    def gps_send(self, m_data):
+        "Send message to GREIS GPS"
+
+        m_all = self.make_pkt(m_data)
+        if not opts['read_only']:
+            io_handle.ser.write(m_all)
+            if VERB_INFO <= opts['verbosity']:
+                print("sent:", m_all)
+                self.decode_msg(m_all)
+                sys.stdout.flush()
+
+    # Table of known options.  From table 4-2 of the specification.
+    oafs = (
+        b"_AJM",
+        b"AUTH",
+        b"_BLT",
+        b"_CAN",
+        b"CDIF",
+        b"CMRI",
+        b"CMRO",
+        b"COMP",
+        b"COOP",
+        b"COPN",
+        b"CORI",
+        b"_CPH",
+        b"DEVS",
+        b"DIST",
+        b"_DTM",
+        b"_E5B",
+        b"_E6_",
+        b"EDEV",
+        b"ETHR",
+        b"EVNT",
+        b"_FRI",
+        b"_FRO",
+        b"_FTP",
+        b"_GAL",
+        b"GBAI",
+        b"GBAO",
+        b"GCLB",
+        b"_GEN",
+        b"_GEO",
+        b"_GLO",
+        b"_GPS",
+        b"_GSM",
+        b"HTTP",
+        b"_IMU",
+        b"INFR",
+        b"IRIG",
+        b"IRNS",
+        b"JPSI",
+        b"JPSO",
+        b"_L1C",
+        b"_L1_",
+        b"_L2C",
+        b"_L2_",
+        b"_L5_",
+        b"LAT1",
+        b"LAT2",
+        b"LAT3",
+        b"LAT4",
+        b"LCS2",
+        b"L_CS",
+        b"_LIM",
+        b"LON1",
+        b"LON2",
+        b"LON3",
+        b"LON4",
+        b"MAGN",
+        b"_MEM",
+        b"_MPR",
+        b"OCTO",
+        b"OMNI",
+        b"_PAR",
+        b"PDIF",
+        b"_POS",
+        b"_PPP",
+        b"_PPS",
+        b"PRTT",
+        b"_PTP",
+        b"QZSS",
+        b"RAIM",
+        b"_RAW",
+        b"RCVT",
+        b"RM3I",
+        b"RM3O",
+        b"RS_A",
+        b"RS_B",
+        b"RS_C",
+        b"RS_D",
+        b"RTMI",
+        b"RTMO",
+        b"SPEC",
+        b"TCCL",
+        b"_TCP",
+        b"TCPO",
+        b"_TLS",
+        b"TRST",
+        b"UDPO",
+        b"_UHF",
+        b"_USB",
+        b"WAAS",
+        b"WIFI",
+        b"_WPT",
+        )
+
+    def send_able_4hz(self, able):
+        "enable basic GREIS messages at 4Hz"
+
+        self.expect_statement_identifier = 'greis'
+
+        # the messages we want
+        # [SX] requires 3.7 firmware, we use [SI] to support 3.6
+        messages = b"jps/{RT,UO,GT,PV,SG,DP,SI,EL,AZ,EC,SS,ET}"
+
+        if able:
+            # Message rate must be an integer multiple of /par/raw/msint
+            # Default msint is 0.100 seconds, so that must be changed first
+            self.gps_send(b"%msint%set,/par/raw/msint,250")
+
+            self.gps_send(b"%greis%em,," + messages + b":0.25")
+        else:
+            self.gps_send(b"%greis%dm,," + messages)
+
+    def send_able_comp(self, able):
+        "dis/enable COMPASS, aka BeiDou"
+        self.expect_statement_identifier = 'cons'
+        en_dis = b'y' if 1 == able else b'n'
+        self.gps_send(b"%cons%set,/par/pos/sys/comp," + en_dis)
+
+    def send_able_constellations(self, able):
+        "dis/enable all constellations"
+        self.expect_statement_identifier = 'cons7'
+        en_dis = b'y' if 1 == able else b'n'
+        self.gps_send(b"%cons1%set,/par/pos/sys/comp," + en_dis)
+        self.gps_send(b"%cons2%set,/par/pos/sys/gal," + en_dis)
+        # this will fail on TR-G2H, as it has no GLONASS
+        self.gps_send(b"%cons3%set,/par/pos/sys/glo," + en_dis)
+        self.gps_send(b"%cons4%set,/par/pos/sys/gps," + en_dis)
+        self.gps_send(b"%cons5%set,/par/pos/sys/irnss," + en_dis)
+        self.gps_send(b"%cons6%set,/par/pos/sys/sbas," + en_dis)
+        self.gps_send(b"%cons7%set,/par/pos/sys/qzss," + en_dis)
+
+    def send_able_defmsg(self, able):
+        "dis/enable default messages at 1Hz"
+        self.expect_statement_identifier = 'defmsg'
+        if able:
+            self.gps_send(b"%defmsg%em,,jps/RT,/msg/def:1,jps/ET")
+        else:
+            # leave RT and ET to break less?
+            self.gps_send(b"%defmsg%dm,,/msg/def:1")
+
+    def send_able_gal(self, able):
+        "dis/enable GALILEO"
+        self.expect_statement_identifier = 'cons'
+        en_dis = b'y' if 1 == able else b'n'
+        self.gps_send(b"%cons%set,/par/pos/sys/gal," + en_dis)
+
+    def send_able_glo(self, able):
+        "dis/enable GLONASS"
+        self.expect_statement_identifier = 'cons'
+        en_dis = b'y' if 1 == able else b'n'
+        self.gps_send(b"%cons%set,/par/pos/sys/glo," + en_dis)
+
+    def send_able_gps(self, able):
+        "dis/enable GPS"
+        self.expect_statement_identifier = 'cons'
+        en_dis = b'y' if 1 == able else b'n'
+        self.gps_send(b"%cons%set,/par/pos/sys/gps," + en_dis)
+
+    def send_able_ipr(self, able):
+        "dis/enable all Integer Psuedo-Range messages"
+        self.expect_statement_identifier = 'em'
+        if able:
+            self.gps_send(b"%em%em,,jps/{rx,rc,r1,r2,r3,r5,rl}:0.25")
+        else:
+            self.gps_send(b"%em%dm,,jps/{rx,rc,r1,r2,r3,r5,rl}")
+
+    def send_able_irnss(self, able):
+        "dis/enable IRNSS"
+        self.expect_statement_identifier = 'cons'
+        en_dis = b'y' if 1 == able else b'n'
+        self.gps_send(b"%cons%set,/par/pos/sys/irnss," + en_dis)
+
+    def send_able_nmea41(self, able):
+        "dis/enable basic NMEA 4.1e messages at 4Hz"
+
+        self.expect_statement_identifier = 'nmea'
+
+        messages = b"nmea/{GBS,GGA,GSA,GST,GSV,RMC,VTG,ZDA}"
+
+        if able:
+            # set NMEA version 4.1e
+            self.gps_send(b"%nmeaver%set,/par/nmea/ver,v4.1e")
+
+            # Message rate must be an integer multiple of /par/raw/msint
+            # Default msint is 0.100 seconds, so that must be changed first
+            self.gps_send(b"%msint%set,/par/raw/msint,250")
+
+            # now we can set the messages we want
+            self.gps_send(b"%nmea%em,," + messages + b":0.25")
+        else:
+            # disable
+            self.gps_send(b"%nmea%dm,," + messages)
+
+    def send_able_sbas(self, able):
+        "dis/enable SBAS"
+        self.expect_statement_identifier = 'cons'
+        en_dis = b'y' if 1 == able else b'n'
+        self.gps_send(b"%cons%set,/par/pos/sys/sbas," + en_dis)
+
+    def send_able_qzss(self, able):
+        "dis/enable QZSS"
+        self.expect_statement_identifier = 'cons'
+        en_dis = b'y' if 1 == able else b'n'
+        self.gps_send(b"%cons%set,/par/pos/sys/qzss," + en_dis)
+
+    def send_able_snr(self, able):
+        "dis/enable all SNR messages, except [EC]"
+        self.expect_statement_identifier = 'em'
+        if able:
+            self.gps_send(b"%em%em,,jps/{E1,E2,E3,E5,El}:0.25")
+        else:
+            self.gps_send(b"%em%dm,,jps/{E1,E2,E3,E5,El}")
+
+    able_commands = {
+        # en/disable basic GREIS messages at 4HZ
+        "4HZ": {"command": send_able_4hz,
+                "help": "basic GREIS messages at 4Hz"},
+        # en/disable all constellations
+        "CONS": {"command": send_able_constellations,
+                 "help": "all constellations"},
+        # en/disable COMPASS, aka Beidou
+        "COMPASS": {"command": send_able_comp,
+                    "help": "COMPASS"},
+        # en/disable default message set.
+        "DEFMSG": {"command": send_able_defmsg,
+                   "help": "default message set at 1Hz"},
+        # en/disable GALILEO
+        "GALILEO": {"command": send_able_gal,
+                    "help": "GALILEO"},
+        # en/disable GLONASS
+        "GLONASS": {"command": send_able_glo,
+                    "help": "GLONASS"},
+        # en/disable GPS
+        "GPS": {"command": send_able_gps,
+                "help": "GPS"},
+        # en/disable Integer Psuedo Range messages
+        "IPR": {"command": send_able_ipr,
+                "help": "all Integer Psuedo Range messages"},
+        # en/disable IRNSS
+        "IRNSS": {"command": send_able_irnss,
+                  "help": "IRNSS"},
+        # en/disable NMEA 4.1e
+        "NMEA": {"command": send_able_nmea41,
+                 "help": "basic messages NMEA 4.1 at 4Hz"},
+        # en/disable SBAS
+        "SBAS": {"command": send_able_sbas,
+                 "help": "SBAS"},
+        # en/disable all SNRs
+        "SNR": {"command": send_able_snr,
+                "help": "all SNR messages, except [EC]"},
+        # en/disable QZSS
+        "QZSS": {"command": send_able_qzss,
+                 "help": "QZSS"},
+       }
+
+    def send_coldboot(self):
+        "Delete NVRAM (almanac, ephemeris, location) and restart"
+        self.expect_statement_identifier = 'coldboot'
+        self.gps_send(b"%coldboot%init,/dev/nvm/a")
+
+    def send_constellations(self):
+        "poll all constellations"
+        self.expect_statement_identifier = 'cons'
+        self.gps_send(b"%cons%print,/par/pos/sys:on")
+
+    def send_get_id(self):
+        "get receiver id"
+        self.expect_statement_identifier = 'id'
+        self.gps_send(b"%id%print,/par/rcv/id")
+
+    def send_get_oaf(self):
+        "poll OAF (GPS opts)"
+
+        self.expect_statement_identifier = 'opts,_WPT'
+        if VERB_RAW <= opts['verbosity']:
+            # get list of all opts
+            self.gps_send(b"%opts,list%list,/par/opts")
+
+        # request opts one at a time from canned list
+        for s in self.oafs:
+            self.gps_send(b"%%opts,%s%%print,/par/opts/%s" % (s, s))
+
+    def send_get_serial(self):
+        "get receiver serial number"
+        self.expect_statement_identifier = 'serial'
+        self.gps_send(b"%serial%print,/par/rcv/sn")
+
+    def send_reset(self):
+        "reset (reboot) the GPS"
+        self.expect_statement_identifier = 'reset'
+        self.gps_send(b"%reset%set,/par/reset,y")
+
+    def send_set_dm(self):
+        "disable all messages"
+        self.expect_statement_identifier = 'dm'
+        self.gps_send(b"%dm%dm")
+
+    def send_set_ipr(self):
+        "poll Integer Psuedo-Range messages"
+        self.expect_statement_identifier = 'out'
+        self.gps_send(b"%out%out,,jps/{rx,rc,r1,r2,r3,r5,rl}")
+
+    def send_get_snr(self):
+        "poll all SNR messages"
+        # nothing we can wait on, depending on GPS model/configuration
+        # we may never see some of E2, E3, E5 or El
+        self.gps_send(b"%out%out,,jps/{EC,E1,E2,E3,E5,El}")
+
+    def send_set_speed(self, set_speed):
+        "change GPS speed"
+        self.expect_statement_identifier = 'setspeed'
+        self.gps_send(b"%%setspeed%%set,/par/cur/term/rate,%d" %
+                      set_speed)
+
+    def send_get_vendor(self):
+        "get receiver vendor"
+        self.expect_statement_identifier = 'vendor'
+        self.gps_send(b"%vendor%print,/par/rcv/vendor")
+
+    def send_get_ver(self):
+        "get receiver version, per section 4.4.3 of the specification"
+        self.expect_statement_identifier = 'ver'
+        self.gps_send(b"%ver%print,/par/rcv/ver")
+
+    # list of canned commands that can be sent to the receiver
+    commands = {
+        "COLDBOOT": {"command": send_coldboot,
+                     "help": "cold boot the GPS"},
+        "CONS": {"command": send_constellations,
+                 "help": "poll enabled constellations"},
+        "DM": {"command": send_set_dm,
+               "help": "disable all periodic messages"},
+        "ID": {"command": send_get_id,
+               "help": "poll receiver ID"},
+        "IPR": {"command": send_set_ipr,
+                "help": "poll all Integer Psuedo-range messages"},
+        "OAF": {"command": send_get_oaf,
+                "help": "poll all OAF options"},
+        "RESET": {"command": send_reset,
+                  "help": "reset (reboot) the GPS"},
+        "SERIAL": {"command": send_get_serial,
+                   "help": "poll receiver serial number"},
+        "SNR": {"command": send_get_snr,
+                "help": "poll all SNR messages"},
+        "VENDOR": {"command": send_get_vendor,
+                   "help": "poll GPS vendor"},
+        "VER": {"command": send_get_ver,
+                "help": "poll GPS version"},
+        }
+
+
+class gps_io(object):
+    """All the GPS I/O in one place"
+
+    Three types of GPS I/O
+    1. read only from a file
+    2. read/write through a device
+    3. read only from a gpsd instance
+    """
+
+    out = b''
+    ser = None
+    input_is_device = False
+
+    def __init__(self, serial_class):
+        "Initialize class"
+
+        Serial = serial_class
+        # buffer to hold read data
+        self.out = b''
+
+        # open the input: device, file, or gpsd
+        if opts['input_file_name'] is not None:
+            # check if input file is a file or device
+            try:
+                mode = os.stat(opts['input_file_name']).st_mode
+            except OSError:
+                sys.stderr.write('%s: failed to open input file %s\n' %
+                                 (PROG_NAME, opts['input_file_name']))
+                sys.exit(1)
+
+            if stat.S_ISCHR(mode):
+                # character device, need not be read only
+                self.input_is_device = True
+
+            if ((opts['disable'] or opts['enable'] or opts['poll'] or
+                 opts['oaf_name'])):
+
+                # check that we can write
+                if opts['read_only']:
+                    sys.stderr.write('%s: read-only mode, '
+                                     'can not send commands\n' % PROG_NAME)
+                    sys.exit(1)
+                if self.input_is_device is False:
+                    sys.stderr.write('%s: input is plain file, '
+                                     'can not send commands\n' % PROG_NAME)
+                    sys.exit(1)
+
+        if opts['target']['server'] is not None:
+            # try to open local gpsd
+            try:
+                self.ser = gps.gpscommon(host=None)
+                self.ser.connect(opts['target']['server'],
+                                 opts['target']['port'])
+
+                # alias self.ser.write() to self.write_gpsd()
+                self.ser.write = self.write_gpsd
+                # ask for raw, not rare, data
+                data_out = b'?WATCH={'
+                if opts['target']['device'] is not None:
+                    # add in the requested device
+                    data_out += (b'"device":"' + opts['target']['device'] +
+                                 b'",')
+                data_out += b'"enable":true,"raw":2}\r\n'
+                if VERB_RAW <= opts['verbosity']:
+                    print("sent: ", data_out)
+                self.ser.send(data_out)
+            except socket.error as err:
+                sys.stderr.write('%s: failed to connect to gpsd %s\n' %
+                                 (PROG_NAME, err))
+                sys.exit(1)
+
+        elif self.input_is_device:
+            # configure the serial connections (the parameters refer to
+            # the device you are connecting to)
+
+            try:
+                self.ser = Serial.Serial(
+                    baudrate=opts['input_speed'],
+                    # 8N1 is GREIS default
+                    bytesize=Serial.EIGHTBITS,
+                    parity=Serial.PARITY_NONE,
+                    port=opts['input_file_name'],
+                    stopbits=Serial.STOPBITS_ONE,
+                    # read timeout
+                    timeout=0.05,
+                    # pyserial Ver 3.0+ changes writeTimeout to write_timeout
+                    # just set both
+                    write_timeout=0.5,
+                    writeTimeout=0.5,
+                )
+            except Serial.serialutil.SerialException:
+                # this exception happens on bad serial port device name
+                sys.stderr.write('%s: failed to open serial port "%s"\n'
+                                 '   Your computer has these serial ports:\n'
+                                 % (PROG_NAME, opts['input_file_name']))
+
+                # print out list of supported ports
+                import serial.tools.list_ports as List_Ports
+                ports = List_Ports.comports()
+                for port in ports:
+                    sys.stderr.write("    %s: %s\n" %
+                                     (port.device, port.description))
+                sys.exit(1)
+
+            # flush input buffer, discarding all its contents
+            self.ser.flushInput()
+
+        else:
+            # Read from a plain file of GREIS messages
+            try:
+                self.ser = open(opts['input_file_name'], 'rb')
+            except IOError:
+                sys.stderr.write('%s: failed to open input %s\n' %
+                                 (PROG_NAME, opts['input_file_name']))
+                sys.exit(1)
+
+    def read(self, read_opts):
+        "Read from device, until timeout or expected message"
+
+        # are we expecting a certain message?
+        if gps_model.expect_statement_identifier:
+            # assume failure, until we see expected message
+            ret_code = 1
+        else:
+            # not expecting anything, so OK if we did not see it.
+            ret_code = 0
+
+        try:
+            if read_opts['target']['server'] is not None:
+                # gpsd input
+                start = time.clock()
+                while read_opts['input_wait'] > (time.clock() - start):
+                    # First priority is to be sure the input buffer is read.
+                    # This is to prevent input buffer overuns
+                    if 0 < self.ser.waiting():
+                        # We have serial input waiting, get it
+                        # No timeout possible
+                        # RTCM3 JSON can be over 4.4k long, so go big
+                        new_out = self.ser.sock.recv(8192)
+                        if raw is not None:
+                            # save to raw file
+                            raw.write(new_out)
+                        self.out += new_out
+
+                    consumed = gps_model.decode_msg(self.out)
+                    self.out = self.out[consumed:]
+                    if ((gps_model.expect_statement_identifier and
+                         (gps_model.expect_statement_identifier ==
+                          gps_model.last_statement_identifier))):
+                        # Got what we were waiting for.  Done?
+                        ret_code = 0
+                        if not read_opts['input_forced_wait']:
+                            # Done
+                            break
+
+            elif self.input_is_device:
+                # input is a serial device
+                start = time.clock()
+                while read_opts['input_wait'] > (time.clock() - start):
+                    # First priority is to be sure the input buffer is read.
+                    # This is to prevent input buffer overuns
+                    # pyserial 3.0 replaces inWaiting() with in_waiting
+                    if 0 < self.ser.inWaiting():
+                        # We have serial input waiting, get it
+                        # 1024 is comfortably large, almost always the
+                        # Read timeout is what causes ser.read() to return
+                        new_out = self.ser.read(1024)
+                        if raw is not None:
+                            # save to raw file
+                            raw.write(new_out)
+                        self.out += new_out
+
+                    consumed = gps_model.decode_msg(self.out)
+                    self.out = self.out[consumed:]
+                    if ((gps_model.expect_statement_identifier and
+                         (gps_model.expect_statement_identifier ==
+                          gps_model.last_statement_identifier))):
+                        # Got what we were waiting for.  Done?
+                        ret_code = 0
+                        if not read_opts['input_forced_wait']:
+                            # Done
+                            break
+            else:
+                # ordinary file, so all read at once
+                self.out += self.ser.read()
+                if raw is not None:
+                    # save to raw file
+                    raw.write(self.out)
+
+                while True:
+                    consumed = gps_model.decode_msg(self.out)
+                    self.out = self.out[consumed:]
+                    if 0 >= consumed:
+                        break
+
+        except IOError:
+            # This happens on a good device name, but gpsd already running.
+            # or if USB device unplugged
+            sys.stderr.write('%s: failed to read %s\n'
+                             '%s: Is gpsd already holding the port?\n'
+                             % (PROG_NAME, PROG_NAME,
+                                read_opts['input_file_name']))
+            return 1
+
+        if 0 < ret_code:
+            # did not see the message we were expecting to see
+            sys.stderr.write('%s: waited %0.2f seconds for, '
+                             'but did not get: %%%s%%\n'
+                             % (PROG_NAME, read_opts['input_wait'],
+                                gps_model.expect_statement_identifier))
+        return ret_code
+
+    def write_gpsd(self, data):
+        "write data to gpsd daemon"
+
+        # HEXDATA_MAX = 512, from gps.h, The max hex digits can write.
+        # Input data is binary, converting to hex doubles its size.
+        # Limit binary data to length 255, so hex data length less than 510.
+        if 255 < len(data):
+            sys.stderr.write('%s: trying to send %d bytes, max is 255\n'
+                             % (PROG_NAME, len(data)))
+            return 1
+
+        if opts['target']['device'] is not None:
+            # add in the requested device
+            data_out = b'?DEVICE={"path":"' + opts['target']['device'] + b'",'
+        else:
+            data_out = b'?DEVICE={'
+
+        # Convert binary data to hex and build the message.
+        data_out += b'"hexdata":"' + binascii.hexlify(data) + b'"}\r\n'
+        if VERB_RAW <= opts['verbosity']:
+            print("sent: ", data_out)
+        self.ser.send(data_out)
+        return 0
+
+
+def usage():
+    "Print usage information, and exit"
+
+    print("usage: %s [-?hrVW] [-c C] [-d D] [-e E] [-f F] [-O O] [-p P]\n"
+          "            [-R R] [-S S] [-s S] [-v V] [-w W]\n"
+          "            [server[:port[:device]]]\n\n" % PROG_NAME)
+    print('usage: %s [options]\n'
+          '       -?            print this help\n'
+          '       -c C          send command C to GPS\n'
+          '       -d D          disable D\n'
+          '       -e E          enable E\n'
+          '       -f F          open F as file/device\n'
+          '                     default: %s\n'
+          '       -h            print this help\n'
+          '       -O O          send OAF file to GPS\n'
+          '       -p P          send preset GPS command P\n'
+          '       -R R          save raw data from GPS in file R\n'
+          '       -r            open file/device read only\n'
+          '                     default: %s\n'
+          '       -S S          configure GPS speed to S\n'
+          '       -s S          set port speed to S\n'
+          '                     default: %d bps\n'
+          '       -V            print version\n'
+          '       -v V          Set verbosity level to V, 0 to 4\n'
+          '                     default: %d\n'
+          '       -W            force entire wait time, no exit early\n'
+          '       -w W          wait time, exit early on -p result\n'
+          '                     default: %s seconds\n'
+          '       [server[:port[:device]]] Connect to gpsd\n'
+          '                     default port: 2947\n'
+          '                     default device: None\n'
+          '\n'
+          'D and E can be one of:' %
+          (PROG_NAME, opts['input_file_name'], opts['raw_file'],
+           opts['input_speed'], opts['verbosity'], opts['input_wait'])
+          )
+
+    # print list of enable/disable commands
+    for item in sorted(gps_model.able_commands.keys()):
+        print("    %-12s %s" % (item, gps_model.able_commands[item]["help"]))
+
+    print('\nthe preset GPS command P can be one of:')
+
+    # print list of possible canned commands
+    for item in sorted(gps_model.commands.keys()):
+        print("    %-12s %s" % (item, gps_model.commands[item]["help"]))
+    print('\nOptions can be placed in the ZERKOPTS environment variable.\n'
+          'ZERKOPTS is processed before the CLI options.')
+    sys.exit(0)
+
+
+# create the GREIS instance
+gps_model = greis()
+
+if 'ZERKOPTS' in os.environ:
+    # grab the ZERKOPTS environment variable for options
+    opts['progopts'] = os.environ['ZERKOPTS']
+    options = opts['progopts'].split(' ') + sys.argv[1:]
+else:
+    options = sys.argv[1:]
+
+try:
+    (options, arguments) = getopt.getopt(options,
+                                         "?c:d:e:f:hrp:s:w:v:O:R:S:WV")
+except getopt.GetoptError as err:
+    sys.stderr.write("%s: %s\n"
+                     "Try '%s -h' for more information.\n" %
+                     (PROG_NAME, str(err), PROG_NAME))
+    sys.exit(2)
+
+for (opt, val) in options:
+    if opt == '-c':
+        # command
+        opts['command'] = val
+    elif opt == '-d':
+        # disable
+        opts['disable'] = val
+    elif opt == '-e':
+        # enable
+        opts['enable'] = val
+    elif opt == '-f':
+        # file input
+        opts['input_file_name'] = val
+    elif opt == '-h' or opt == '-?':
+        # help
+        usage()
+    elif opt == '-p':
+        # preprogrammed command
+        opts['poll'] = val
+    elif opt == '-r':
+        # read only
+        opts['read_only'] = True
+    elif opt == '-s':
+        # serial port speed
+        opts['input_speed'] = int(val)
+        if opts['input_speed'] not in gps_model.speeds:
+            sys.stderr.write('%s: -s invalid speed %s\n' %
+                             (PROG_NAME, opts['input_speed']))
+            sys.exit(1)
+
+    elif opt == '-w':
+        # max wait time, seconds
+        opts['input_wait'] = float(val)
+    elif opt in '-v':
+        # verbosity level
+        opts['verbosity'] = int(val)
+    elif opt in '-O':
+        # OAF .jpo file
+        opts['oaf_name'] = val
+    elif opt in '-R':
+        # raw log file
+        opts['raw_file'] = val
+    elif opt in '-S':
+        # set GPS serial port speed
+        opts['set_speed'] = int(val)
+        if opts['set_speed'] not in gps_model.speeds:
+            sys.stderr.write('%s: -S invalid speed %s\n' %
+                             (PROG_NAME, opts['set_speed']))
+            sys.exit(1)
+
+    elif opt == '-W':
+        # forced wait, no early exit on command completion
+        opts['input_forced_wait'] = True
+    elif opt == '-V':
+        # version
+        sys.stderr.write('zerk: Version %s\n' % gps_version)
+        sys.exit(0)
+
+if opts['input_file_name'] is None:
+    # no input file given
+    # default to local gpsd
+    opts['target']['server'] = "localhost"
+    opts['target']['port'] = gps.GPSD_PORT
+    opts['target']['device'] = None
+    if arguments:
+        # server[:port[:device]]
+        arg_parts = arguments[0].split(':')
+        opts['target']['server'] = arg_parts[0]
+        if 1 < len(arg_parts):
+            opts['target']['port'] = arg_parts[1]
+            if 2 < len(arg_parts):
+                opts['target']['device'] = arg_parts[2]
+
+elif arguments:
+    sys.stderr.write('%s: Both input file and server specified\n' % PROG_NAME)
+    sys.exit(1)
+
+if VERB_PROG <= opts['verbosity']:
+    # dump all options
+    print('Options:')
+    for option in sorted(opts):
+        print("   %s: %s" % (option, opts[option]))
+
+# done parsing arguments from environment and CLI
+
+try:
+    # raw log file requested?
+    raw = None
+    if opts['raw_file']:
+        try:
+            raw = open(opts['raw_file'], 'w')
+        except IOError:
+            sys.stderr.write('%s: failed to open raw file %s\n' %
+                             (PROG_NAME, opts['raw_file']))
+            sys.exit(1)
+
+    # create the I/O instance
+    io_handle = gps_io(serial)
+
+    # keep it simple, only one of -O, -c -d -e or -S
+    if opts['oaf_name'] is not None:
+        # parse an OAF file
+        try:
+            oaf_root = xml.etree.ElementTree.parse(opts['oaf_name']).getroot()
+            oaf = dict()
+            for tag in ('id', 'oaf', 'hash'):
+                oaf[tag] = oaf_root.find(tag).text
+            oaf['oaf'] = oaf['oaf'].split('\n')
+            if VERB_PROG <= opts['verbosity']:
+                print(oaf)
+        except xml.etree.ElementTree.ParseError:
+            sys.stderr.write('%s: failed to parse OAF "%s"\n'
+                             % (PROG_NAME, opts['oaf_name']))
+            sys.exit(1)
+        except IOError:
+            sys.stderr.write('%s: failed to read OAF "%s"\n'
+                             % (PROG_NAME, opts['oaf_name']))
+            sys.exit(1)
+
+        # calculate hash
+        oaf_s = '\n'.join(oaf['oaf'])
+        hash_s = hashlib.sha1(oaf_s).hexdigest()
+        if hash_s != oaf['hash']:
+            sys.stderr.write('%s: OAF bad hash "%s", s/b %s\n'
+                             % (PROG_NAME, hash_s, oaf['hash']))
+            sys.exit(1)
+
+        # TODO: probably should check the ID first...
+        # TODO: prolly should send one command per handshake
+        # blasting all commands at once, seems to not work reliably
+        for command in oaf['oaf']:
+            time.sleep(0.1)           # wait 0.1 seconds each
+            gps_model.gps_send(command)
+        # this will detect when it is all done
+        gps_model.gps_send(b'%DONE%')
+        gps_model.expect_statement_identifier = 'DONE'
+
+    elif opts['command'] is not None:
+        # zero length is OK to send
+        if 1 < len(opts['command']) and '%' != opts['command'][0]:
+            # add ID, if missing
+            gps_model.expect_statement_identifier = 'CMD'
+            opts['command'] = "%CMD%" + opts['command']
+
+        # add trailing new line
+        opts['command'] += "\n"
+
+        if VERB_QUIET < opts['verbosity']:
+            sys.stderr.write('%s: command %s\n' % (PROG_NAME, opts['command']))
+        gps_model.gps_send(opts['command'])
+
+    elif opts['disable'] is not None:
+        if VERB_QUIET < opts['verbosity']:
+            sys.stderr.write('%s: disable %s\n' % (PROG_NAME, opts['disable']))
+        if opts['disable'] in gps_model.able_commands:
+            command = gps_model.able_commands[opts['disable']]
+            command["command"](gps_model, 0)
+        else:
+            sys.stderr.write('%s: disable %s not found\n' %
+                             (PROG_NAME, opts['disable']))
+            sys.exit(1)
+
+    elif opts['enable'] is not None:
+        if VERB_QUIET < opts['verbosity']:
+            sys.stderr.write('%s: enable %s\n' % (PROG_NAME, opts['enable']))
+        if opts['enable'] in gps_model.able_commands:
+            command = gps_model.able_commands[opts['enable']]
+            command["command"](gps_model, 1)
+        else:
+            sys.stderr.write('%s: enable %s not found\n' %
+                             (PROG_NAME, opts['enable']))
+            sys.exit(1)
+
+    elif opts['poll'] is not None:
+        if VERB_QUIET < opts['verbosity']:
+            sys.stderr.write('%s: poll %s\n' % (PROG_NAME, opts['poll']))
+        if opts['poll'] in gps_model.commands:
+            command = gps_model.commands[opts['poll']]
+            command["command"](gps_model)
+        else:
+            sys.stderr.write('%s: poll %s not found\n' %
+                             (PROG_NAME, opts['poll']))
+            sys.exit(1)
+
+    elif opts['set_speed'] is not None:
+        gps_model.send_set_speed(opts['set_speed'])
+
+    exit_code = io_handle.read(opts)
+
+    if ((VERB_RAW <= opts['verbosity']) and io_handle.out):
+        # dump raw left overs
+        print("Left over data:")
+        print(io_handle.out)
+
+    sys.stdout.flush()
+    io_handle.ser.close()
+
+except KeyboardInterrupt:
+    print('')
+    exit_code = 1
+
+sys.exit(exit_code)