I am attempting to get GPS working on a custom board which uses a Fanstel m2 nrf52840 + nrf9160 module. I am also using a nRF9160-DK board, the one with the integrated GPS (Tagolas) antenna.
The nRF9160 on both devices has been loaded with the mfw_nrf9160_1.3.3.zip modem firmware. I've also downloaded the latest SDK version 2.3.0 and build and programmed the serial_lte_modem project.
The AT commands I'm using are:
```
AT%XSYSTEMMODE=1,0,1,0
AT%XCOEX0=1,1,1570,1580
AT%XMAGPIO=1,0,0,1,1,1574,1577
AT+CFUN=1
AT#XGPS=1,1
```
If I go outside, the DK board will eventually start to produce some GPS messages, while our Fanstel board does not.
In terms of hardware, there are a few differences between the devices. The DK is using an integrated Tagolas GPS antenna. The Fanstel is using some integrated internal antenna -- there is is some pad for a u.fl external antenna but it is not populated.
Looking at the schematic, the Fanstel has am amplifier which has its GPS_EN connected on the nrf9160 to MAGPIO0. On the DK, older schematic also had this arrangement, while some newer schematic had GPS_EN connected to COEX0.
At this point, I am just using the default unmodified code for the serial_lte_modem project. I'm hoping the issue is something like the GPS_EN but am not sure. I'm not sure what to do to get the GPS up and running on the Fanstel. Outside of GPS, the unit works just fine.
