GNSS issue with a **RAK8213** module

Cellular Boards RAK8213
1

Hello,

I am currently facing a GNSS issue with a RAK8213 module and I would like to ask for your help.

My setup

  • Module: RAK8213
  • Platform: RAK 7391
  • GNSS antenna: connected to the correct GNSS connector
  • I also placed the antenna outside near a window / open area
  • LTE works correctly, but GNSS never gets a valid fix

Problem description

The GNSS seems to start correctly, because I can read NMEA messages, but I never get valid coordinates.

The messages I continuously receive are:

$GPVTG,T,M,N,K,N*2C
$GPGSA,A,1,*1E
$GPGGA,0,66
$GPRMC,V,N53


These messages repeat again and again, with:

* no latitude / longitude
* no valid fix
* no satellites used

So the GNSS is outputting NMEA, but it never reaches a position fix.

## What I already tested

I have been working on this problem for about **one month**.

I already tested the following:

* checked that the **GNSS antenna is connected to the correct pin**
* placed the antenna outside for better sky visibility
* changed the **LTE/GNSS module** with another one
* the antenna works on another platform
* repeated many GNSS tests and AT commands
* restarted GNSS multiple times
* tested different serial ports
* stopped ModemManager during AT tests

## AT command tests

I already tested several commands such as:

```text
AT
AT+QGPS?
AT+QGPS=1
AT+QGPSEND
AT+QGPSLOC=2
AT+QGPSGNMEA="GGA"
AT+QGPSGNMEA="RMC"
AT+QGPSGNMEA="GSV"
AT+QGPSCFG="outport","usbnmea"
AT+QGPSCFG="nmeasrc",1
AT+QGPSCFG="gnssconfig",1

But the result is always the same:

  • GNSS starts
  • NMEA output is present
  • but no valid coordinates are obtained

Any help or feedback would be greatly appreciated.

Thank you.