Hello,
I am facing an issue with my Quectel GPS module (model LC86L) and I am looking for a solution. The GPS module sees 10 satellites, but it is often unable to get a fix. Occasionally, it does get a fix, but it is usually only for a short time. I am struggling to get a stable fix, and most of the time I am getting the “no fix” error.
Even though the satellite count is high, the position accuracy is very low and I am unable to get reliable position data. Even with some error, I would like to receive position data. It is much better to receive even inaccurate position data than to receive nothing at all.
I have tried almost all of the settings in the protocol to solve this issue, and I have used the following commands:
- PMTK300 (position update rate)
- PMTK251 (fix time settings)
- PMTK223 (dynamic ephemeris extension)
- PMTK225 (periodic mode for power saving)
- PMTK353 (multi-GNSS search mode - GPS, GLONASS, Galileo, Beidou)
- PMTK869 (EASYTM - Time to First Fix acceleration)
- PMTK286 (AIC function)
- PMTK301 (DGPS mode settings)
Despite trying all these settings, I am still unable to get a stable fix, and even with the lowest error margin, I cannot get any position data. Below, I have included the data I am receiving, along with the version information for my GPS module:
Sample Data (10 Satellites Seen, No Fix):
$GPRMC,193700.000,V,,,,,0.25,116.47,281224,,,N,V*36<CR><LF>
$GPVTG,116.47,T,,M,0.25,N,0.47,K,N*33<CR><LF>
$GPGGA,193700.000,,,,,0,0,,,M,,M,,*44<CR><LF>
$GPGSA,A,1,,,,,,,,,,,,,,,,1*03<CR><LF>
$GPGSA,A,1,,,,,,,,,,,,,,,,2*00<CR><LF>
$GPGSV,3,1,10,23,72,112,24,16,55,267,24,18,50,051,,10,45,191,39,0*6F<CR><LF>
$GPGSV,3,2,10,26,43,219,37,27,39,309,,40,31,133,31,15,21,067,18,0*67<CR><LF>
$GPGSV,3,3,10,29,17,115,36,13,05,039,,0*64<CR><LF>
$GLGSV,1,1,01,74,,,,1*7A<CR><LF>
$GPGLL,,,,,193700.000,V,N*76<CR><LF>
As you can see from the data above, even though my GPS device sees 10 satellites, it is still not getting a fix. The position accuracy and satellite signal strength are very low. Only short-duration fixes are obtained, but they are lost almost immediately. That being said, I would still like to get position data even if it has a high error margin.
Version Information:
- Version Info: $PQVERNO,R,L86NR03A01S,2020/02/27,02:42*64
I am looking for guidance on how to get position data in this situation and speed up the fix time. Low position accuracy is not an issue, I just want to get at least some position data in every case.
Thank you,
Best regards,