+typedef int32_t gps_alt_t;
+#define AO_TELEMETRY_LOCATION_ALTITUDE(l) (((gps_alt_t) (l)->altitude_high << 16) | ((l)->altitude_low))
+#define AO_TELEMETRY_LOCATION_SET_ALTITUDE(l,a) (((l)->altitude_high = (a) >> 16), \
+ ((l)->altitude_low = (a)))
+