Add GPS altitude parsing

openrtx/include/state.h

@@ -51,6 +51,7 @@ typedef struct
     sat_t satellites[12]; // Details about satellites in view
     float latitude;       // Latitude coordinates
     float longitude;      // Longitude coordinates
+    float altitude;       // Antenna altitude above mean sea level (geoid) in m
     float speed;          // Ground speed in km/h
     float tmg_mag;        // Course over ground, degrees, magnetic
     float tmg_true;       // Course over ground, degrees, true

openrtx/src/gps.c

@@ -51,6 +51,7 @@ void gps_taskFunc(char *line, int len, gps_t *state)
             if (minmea_parse_gga(&frame, line)) {
                 state->fix_quality = frame.fix_quality;
                 state->satellites_tracked = frame.satellites_tracked;
+                state->altitude = minmea_tofloat(&frame.altitude);
             }
         } break;