I have a Raspberry Pi 3 with Adafruit's Ultimate GPS Pi Hat. I was able to successfully install gpsd and chrony. I am now getting NMEA and PPS thumbs up.
But I have a weird issue. The Ultimate GPS module is spitting out more NMEA messages than I want: I want only GPGGA and GPRMC....but it is also replying with GPGSA, GPGSV, and GPZDA.
So Adafruit has some Python code/libraries that allows you to interface with the GPS module and 'talk' to it (https://github.com/adafruit/Adafruit_GPS). Using this code I was able to send the following packet using the PMTK command packet (https://cdn-shop.adafruit.com/datasheets/PMTK_A11.pdf)
$PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28<CR><LF>
I then opened up Putty and using a 9600 serial connection to /dev/ttyAMA0 I see indeed that only GPGGA and GPRMC are being processed out:
BUT...as soon as I reopen gpsmon/gpsd, all the NMEA message streams are reactivated'...what the heck ??
If I don't open gpsd/gpsmon...indeed only GPGGA and GPRMC are active.
Has anyone come across this issue before ?
