DGPS

The Differential GPS present here is based on the Ublox chip M8P. There are two types of Ublox M8P:

• NEO-M8P-0: acting as the rover (mobile)
• NEO-M8P-2: acting as the rover (mobile) or as the ground station

The NEO-M8P-2 acting as the ground station must know its position. This can be done by locating the ground antenna to a know position and initializing the ublox to this position, or programming the ublox to send its estimated position after a given converging time and precision. Furthermore the ublox acquire observation data and output them with its position to the NEO-M8P rover (mobile).

The ground station output three messages types of the RTCM3 standard to the rover (mobile):

• RTCM3.2 1005 : Ground station position
• RTCM3.2 1077 : GPS observation data
• RTCM3.2 1087 : Beidou observation data

The NEO-M8P acting as a rover (mobile) computes the position of the ground station acquire observation data from its mobile position and These data are transmitted as new messages within the paparazzi telemetry. The