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,V29 | | 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,N2C | | 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.