Quectel GPS Module Sees 10 Satellites But Cannot Get a Fix - Need Help

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,

Hi @esekerci

  1. Although 10 satellites have been found, the satellite signals are relatively weak and it is normal that the positioning is not possible.
  2. What antenna are you using? Is the test environment open? If not, it is recommended that you connect an external active antenna and verify whether the module can be stably positioned in an open outdoor environment.
  3. Our factory equipment is configured, and generally you do not need to send the commands you find.
  4. I sent you the latest version by email. You can try to upgrade it. Please read the “Quectel_L86_Firmware_Release_Notes_V1301S.pdf” in the firmware carefully before upgrading. If you are in some special areas, your module may become a brick.
  5. The upgrade tool is large, please download it from the following path: https://www.quectel.com.cn/download/qgnss_v1-4