RT_GPS_Pos_LLH GPS accuracy and latitude
RT_GPS_Pos_LLH_1: 140, 2 (0x8C0220 + unit id) (0x302)
Byte 0: Validity
Byte 1: Accuracy Latitude (m)
Byte 2: Accuracy Longitude (m)
Byte 3: Accuracy Altitude (m)
Bytes 4-7: Latitude (degrees)
Accuracy resolution is m * 0.1
Latitude resolution is degrees * 1e-7.
The validity byte is used for the data packets in this message *and* in RT_GPS_Pos_LLH_2.
Accuracy value have a resolution of 0.1m. The accuracy figures are a 1 sigma estimate of the accuracy for the position.