Hello,
I’m implementing the Quectel EG21-GL module in a new project and this is my first experience with GNSS systems. I’m experiencing an issue with satellite constellation detection:
Current Behavior:
- GPS and GLONASS satellites are detected (after 30-40 minutes with an active antenna)
- Galileo satellites are NOT detected
- BeiDou satellites are NOT detected
- Time to first fix outside with open sky is very long (~30-40 minutes)
Expected Behavior:
- All four constellations should be detected: GPS, GLONASS, Galileo, and BeiDou
- First fix should be significantly shorter
Hardware Setup:
- Module: EG21-GL (firmware version EG21GLGAR07A03M1G_A0.300.A0.300)
- Antenna: Active antenna (>3.9 volt, facing sky, magnetic base on a metal shield)
- Location: Open sky environment
- AT interface: Standard UART connection
Configuration Attempted:
AT+QGPSEND
AT+QGPSCFG="gnssconfig",1
AT+QGPSCFG="gpsnmeatype",31
AT+QGPSCFG="glonassnmeatype",7
AT+QGPSCFG="galileonmeatype",1
AT+QGPSCFG="beidounmeatype",3
AT+QGPSCFG="gsvextnmeatype",1
AT+QGPSCFG="outport","usbnmea"
AT+QGPSCFG="fixfreq",1
AT+QGPSCFG="nmeasrc",1
AT+QGPSCFG="agpsposmode",775
AT+CFUN=1,1
AT+QGPSDEL=0
AT+QGPS=1,255,50,0,1
AT+QGPSLOC=0 (ret 516 no pos)
Observations after 30 minutes :
- Only GPS (7 satellites) and GLONASS (7 satellites) appear in NMEA output
- No Galileo or BeiDou satellites detected
- NMEA sentences confirm only 2D positioning with few satellites
Questions:
- Is the EG21-GL firmware A0.300 supposed to support all four constellations simultaneously?
- Could this be a hardware limitation or antenna compatibility issue?
- Are there additional AT commands needed for constellation configuration?