EG91-NS/NAXD GNSS Performance Issue

IoT Modules GNSS Module
1

Summary the issue that we are facing:

Module NS/NAXD

  1. Scanning network B2,B4,B5,B12,B13,B25,B26 (not connecting)
    -with GPS signal at -130dBm, SNR =37
    -Tried CFUN=0, SNR is still 37

  2. Connected to call box on either one of the bands, B2,B4,B5,B12,B13,B25,B26

  • with GPS signal at -130dBm, SNR =32

Module AUX

  1. Scanning network B1,B2,B3,B4,B5,B7,B8,B28 (not connecting)
    -with GPS signal at -130dBm, SNR =42

  2. Connected to call box on either one of the bands, B1,B2,B3,B4,B5,B7,B8,B28

  • with GPS signal at -130dBm, SNR =41

From the data above looks like we have 2 issues here, module is scanning, and module connected to call box.

We had tried to add a series of resonator to attenuate B13 and B14,but still no improvement.

With AT command AT+CFUN=0/=4, also no improvement…

Is anyone able to advise on our findings above?

2

Dear Sir,
It seems that there’s something wrong with EG91-NS/NAXD GNSS RF signal.
One is the GNSS signal strength is not good as that of Module AUX. Another one is that the GNSS signal is likely to be affected by other bands.
It’s recommended to provide your SCH for checking and also your device needs RF related testing.
You can contact with our local FAE or email to support@quectel.com for above support.

Thanks.
BRs

3

To add on, both AUX and NS/NAXD are share the same schematic and layout…the only difference is using different module…