BG77 GNSS Unable to Fix Position

Hello,

We are experiencing an issue with the GNSS functionality on our custom board using the Quectel BG77 module. The GNSS fails to fix a position, and the output consistently shows incomplete or invalid NMEA sentences (e.g., $GPGGA,0,*66).

Here are the relevant logs from our system:
I (5004) main: BG77 initialized
I (5004) BG77: Command: AT+QGPS=1,1
I (5014) main: GPS enabled
I (9014) main: FW version: BG77LAR02A04 | | OK
I (9024) main: QFW version: BG77LAR02A04_01.204.01.204 | | OK
I (9024) main: nmeasrc Data: OK
I (9034) main: priority Data: +QGPSCFG: “priority”,0,4 | | OK
I (9044) main: gnssconfig Data: +QGPSCFG: “gnssconfig”,3 | | OK
I (9054) main: gnssconfig Data: OK
I (9064) main: gnssconfig Data: +QGPSCFG: “gnssconfig”,3 | | OK
I (9074) main: NMEA Data: +QGPSGNMEA: (“GGA”,“RMC”,“GSV”,“GSA”,“VTG”) | | OK
I (9084) main: ERROR: +CME ERROR: 516
I (9084) main: Retrying…
I (10094) main: GGA Data: +QGPSGNMEA: $GPGGA,0,66 | | OK
I (11104) main: RMC Data: +QGPSGNMEA: $GPRMC,V,N,V
29 | | OK
I (12104) main: GSV Data: OK
I (13114) main: GSA Data: +QGPSGNMEA: $GPGSA,A,1,32 | | OK
I (14124) main: VTG Data: +QGPSGNMEA: $GPVTG,T,M,N,K,N
2C | | OK
I (15124) main: ERROR: +CME ERROR: 516
I (15124) main: Retrying…

We are confident that the issue is not related to the hardware design, as we are using the same design and antenna setup on other boards, which work perfectly.
The antenna is a passive NN03-320, and we have verified the impedance matching network.

Could this issue be related to the firmware version or a module-specific problem?
Are there additional diagnostic commands or configurations we should try to better identify the root cause?
Has anyone else experienced similar behavior, even with validated hardware designs?

Any guidance or suggestions would be greatly appreciated!
Thank you in advance for your help.

Hi @mikey
Please assist in solving customer problems.Thanks.

Check your antenna specification does not include these frequencies please.

Hi Mikey,

Our antenna includes these frecuencies.

Could you please let us know how long it might take for the module to achieve its first fix under normal conditions? Additionally, should we expect faster results if we move to an open-sky location? Currently, we are testing in the middle of the city.

Thank you,

The TTFF(Time to First Fix) is about 10/30 seconds (with/without XTRA under the open sky, respectively).If it is the signal issue, move to open sky may be helpful.And if you want I can send you the GNSS Application Note for BG77 so that you can test better.

Could you please provide the firmware version BG77LAR02A04_01.204.01.204 so that we can install it on our Quectel Evaluation Board?

The latest FW version I have is BG77LAR02A04_A0.206.A0.206 if you want I can send you.

Hey Mikey,

Yes please!

Thank you

OK I have send it to you and check your email please.