Longitude not showing correctly

[segoz]

Hello and thank you for your work. This project is amazing and I would like to use it in a personal GPS tracker for my car. Everything is working fine (GPS fetch, modem connection, GPRS and MQTT publishing) except that the longitude value is always "65533.000000". I tried to fix it but i'm completely useless with coding and have no programming skills.

Here you can find an extract of the output from SIM808 module (i've put some XXXX for privacy):

**
GNSINF: 1,1,20201117202729.000,40.62XXXX,-3.99XXXX,882.500,2.02,57.3,1,,1.1,1.4,0.9,,8,7,,,40,,
< OK
160: (gps) longitud: 65533.000000
160: (gps) latitud: 40.628943
160: (gps) altitud: 883
160: (gps) km/h: 2
160: (gps) satélites: 7
160: (gps) dirección: 57.30
160: (gps) fecha GPS: 17-11-2020
160: (gps) hora GPS: 20:27:29
160: -> ok
**

I guess it should be happening because of an error in the conversion process of the NMEA string received from SIM808, but i'm not able to find how to fix it.

Any help will be much appreciated.

Regards.