Yes, you can access the GPS.
For antenna, you could use a standard GNSS antenna(L1 freq) with builtin LNA. According to the schematics, the antenna socket is powered, so LNA will work. I’ve tested one on my device.
For software, you need to use Modem Manager(MM) to enable the GNSS function. Due to an implementation issue of MM, the GNSS function cannot work without an actual sim card inserted.
Then you have two options: either use gpsd or use MM+dbus. gpsd need full control over GNSS serial port(ttyUSB1 if I’m right), so the command line option for enabling the GNSS function is different.
For gpsd: mmcli -m any --location-enable-gps-unmanaged
For MM+dbus: mmcli -m any --location-enable-gps-nmea --location-enable-gps-raw
As to the configurations for gpsd, please refer to it’s manual.