RG255C-GL not acquiring GPS fix

IoT Modules 5G Module
1

Dear forum,

I’m testing an RG255C-GL (p/n RG255CGL00AB-4M2-M20AA ) on a custom board. The WWAN side of things is working as expected, however I’m having some issues with the GNSS.

The module is connected to a GPS antenna (which we know works).
After turning on the GPS (AT+QGPS=1) NMEA0183 sentences are written on /dev/ttyUSB1 as expected, however, even after several tens of minutes, the GPS can’t get a fix.

Here is the configuration:

ATI
Quectel
RG255C-GL
Revision: RG255CGLABR01A04M4G

OK
AT+QGPSCFG="gpsnmeatype"
+QGPSCFG: "gpsnmeatype",31

OK
AT+QGPSCFG="beidounmeatype"
+QGPSCFG: "beidounmeatype",1

OK
AT+QGPSCFG="galileonmeatype"
+QGPSCFG: "galileonmeatype",31

OK
AT+QGPSCFG="glonassnmeatype"
+QGPSCFG: "glonassnmeatype",4

OK
AT+QGPSCFG="outport"
+QGPSCFG: "outport",usbnmea

OK

My questions are:

  • Am I missing something?
  • Are there newer firmware/known bugs?
  • Is there a module-specific guide on how to use the GNSS?
  • As a last resort, does my p/n have the GNSS?

Best regards,
Gab

2

I have sent you the GNSS instruction manual and the hardware design manual. Please check them.

3

Hello @herbert.pan-Q ,
Thank you very much for the documents. The hardware reference manual seems to be for a different form factor (LGA), while I have the m.2. Do you have the m.2 version?

I tried to enable everything following the GNSS documents, but still no fix. The parameters I set:

AT+QGPSCFG="gpsnmeatype",31
AT+QGPSCFG="glonassnmeatype",7
AT+QGPSCFG="galileonmeatype",31
AT+QGPSCFG="beidounmeatype",7
AT+QGPSCFG="gnssconfig",1
AT+QGPSCFG="multibandconfig",39

Can you confirm that I have a model with the GNSS?

Please find attached the gpsd logs if you think it may be useful: gpsd.txt (43.9 KB)

Best regards,
Gab

4

Dear @gab
From nmea sentences, it didn’t have any satellites was found, so it is hard to fix.
Please confirm your antenna meet requirement and connect correct port.
I sent the M2 HD document to you via Message, please check.

5

Hello,

We found the issue, we were unknowingly using active antennas instead of passive ones.

Thank you for your support,
Gab