Setup NMEA Port
This topic summarizes how to setup an NMEA port on the AR755x platform.
Setup Target
To setup an AR755x target, run the follow commands (only once):
AT!ENTERCND="A710"AT!CUSTOM="GPSENABLE",1AT!CUSTOM="NMEAENABLE",1AT!CUSTOM="GPSSEL",1AT!GPSQMICONFIG=1AT!GPSNMEA=1AT!GPSNMEACONFIG=1,1AT!GPSNMEASENTENCE=29FFAT!GPSONLY=0AT!RESET
Start NMEA
Once, the target is setup, run this on the AR755x Linux console:
start NMEA device:echo '$GPS_START' > /dev/nmea
Then "/dev/nmea" file can be open in order to parse the NMEA frames.
- Warning
- If you need to use Legato positioning service in parallel, you can't use this command; you have to use le_posCtrl_Request().
Stop NMEA
To stop the NMEA, run this on the AR755x Linux console:
echo '$GPS_STOP' > /dev/nmea
- Warning
- If you need to use Legato positioning service in parallel, you can't use this command; you have to use le_posCtrl_Release().
Get NMEA stream
Here's an example of a dump of GNSS NMEA frames (here only $GNxxx frames):
echo '$GPS_START' > /dev/nmeacat /dev/nmea | grep '$GN'$GNGNS,094821.0,4849.931307,N,00216.053323,E,AA,14,0.6,161.5,48.0,,*6D$GNGSA,A,2,05,13,18,21,27,29,31,,,,,,1.0,0.6,0.7*2C$GNGSA,A,2,68,69,74,75,76,84,86,,,,,,1.0,0.6,0.7*2E$GNGNS,094822.0,4849.931277,N,00216.053326,E,AA,15,0.6,161.5,48.0,,*6C$GNGSA,A,2,05,13,16,18,21,27,29,31,,,,,0.9,0.6,0.7*23$GNGSA,A,2,68,69,74,75,76,84,86,,,,,,0.9,0.6,0.7*26$GNGNS,094823.0,4849.931249,N,00216.053330,E,AA,15,0.6,161.5,48.0,,*67$GNGSA,A,2,05,13,16,18,21,27,29,31,,,,,0.9,0.6,0.7*23$GNGSA,A,2,68,69,74,75,76,84,86,,,,,,0.9,0.6,0.7*26$GNGNS,094824.0,4849.931225,N,00216.053333,E,AA,15,0.6,161.5,48.0,,*69$GNGSA,A,2,05,13,16,18,21,27,29,31,,,,,0.9,0.6,0.7*23$GNGSA,A,2,68,69,74,75,76,84,86,,,,,,0.9,0.6,0.7*26Decoding...$GNGNS: GNSS Fix datahttp://www.catb.org/gpsd/NMEA.html#_gns_fix_data$GNGSA: GNSS Active Satellites + Dilution of precisionhttp://www.catb.org/gpsd/NMEA.html#_gsa_gps_dop_and_active_satellites2D-Fix with:- 8 GPS Satellites: 05,13,16,18,21,27,29,31- 7 Glonass Satellites: 68,69,74,75,76,84,86Time: 094824.0 --> 09:48:24 (UTC)Latitude: 4849.931225,N --> 48 + (49.931225 / 60) = 48.83218708333333Longitude: 00216.053333,E --> 002 + (16.053333 / 60) = 2.26755555https://www.google.fr/maps/@48.8321871,2.2675556,17z
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