RAK2245 TTN-Gateway: no GPS?

@ ZhuQI:

Thanks for the information. It gave me some helpful things to try.

  1. I removed the GPS antenna. Checked the connectors under a magnifying glass and found no damage.

  2. I disabled serial login and enabled the serial port, as your screen shots showed; I disabled ttn-gateway.service; then I rebooted.

  3. cat /dev/ttyAMA0 now gives me a constant stream that looks something like:
    ?b ?I???2?$GPRMC,V,N*53
    $GPVTG,N*30
    $GPGGA,0,00,99.99,*48
    $GPGSA,A,1,99.99,99.99,99.99*30
    $GPGLL,V,N*64
    $GPTXT,01,01,01,NMEA unknown msg*58

    in which I’m now getting the NMEA word in the output (which I had not seen earlier) and some semblance of GPS readings.

  4. Power off; reattach GPS antenna; reboot. cat /dev/ttyAMA0 now gives:

    $GPGLL,V,N*64
    ?b ???׍$GPRMC,V,N*53
    $GPVTG,N*30
    $GPGGA,0,00,99.99,*48
    $GPGSA,A,1,99.99,99.99,99.99*30
    (no $GPTXT and NMEA phrases!)

  5. Run ./start.sh in lora_pkt_fwd and I get # no valid GPS coordinates available yet, as before.

  6. If I run the GPS tester again, I get

    lora_gateway/libloragw# ./test_loragw_gps
    Beginning of test for loragw_gps.c
    *** Library version information ***
    Version: 5.0.1;
    ~~ UBX NAV-TIMEGPS sentence, triggering synchronization attempt ~~
    No valid reference GPS time available, synchronization impossible.

So the problem persists. This looks like the GPS system just isn’t getting signal from the antenna or that the antenna just doesn’t have a clear view of the sky (but it does).

If the problem exists, can we resolve it remotely?
I am online from 01:00 to 11:00 UTC.

I’m not sure how to solve this remotely, but I’m willing to give it a try. It’s now 12:04 UTC so you’re offline. 1:00 UTC is 20:00 my time; I’ll likely be spending time with my wife then but should be available about 22:00 (3:00 UTC).

Meanwhile, if you can think of anything else for me try, please let me know.

David