gpsprobe 1 8 Sep 2004 gpsprobe probe a GPS for type, send-cycle time and accuracy information gpsprobe -b speed -h -n packetcount device gpsprobe samples the NMEA data stream from a GPS and attempts to deduce various interesting pieces of information, including: the GPS type (what chipset it uses) the GPS protocol (NMEA or SiRF) the inventory of NMEA sentence types it emits its send cycle (frequency of updates) In addition, if the GPS is getting position fixes, gpsprobe generates a scattergram from them and plots a probable-error circle. This data is only meaningful if the GPS is held stationary while gpsprobe is running. Use it in combination with gpsprof1 to get a feel for the accuracy of your GPS. The report and scattergram is generated as a gnuplot1 script to standard output. View it with gnuplot -persist <foo> where <foo> should be replaced with the name of the plot script. Note: gpsprobe needs access to the raw GPS device. Therefore gpsd must not be running when you call gpsprobe. You will probably have to run as superuser to get access to the device. The -b option sets a baud rate at which to connect. If no -b option is given, gpsprobe will hunt through plausible baud rates beginning with the NMEA standard 4800, looking for one that elicits text looking like NMEA sentences. The -n option sets the number of packets to sample. The default is 100. The -h option makes gpsprobe print a usage message and exit. The argument, if given, sets the name of the GPS device. The default is /dev/gps. This program handles only straight NMEA devices. There is code that attempts to recognize a GPS emitting SiRF binary protocol and switch it to NMEA, but it is not well tested and probably fragile. This program won't handle the Garmin or Rockwell binary protocols at all. The logic for hunting the GPS's baud rate is vulnerable to various sorts of RS323 flakiness. If it hangs for longer than a few seconds, kill the program and restart. gpsd1 libgps3 libgpsd3 gpsprof1 gpsfake1 gnuplot1 Eric S. Raymond esr@thyrsus.com. There is a project page for gpsd here.