Precise 6D RTK Positioning System for UAV-based Near-Field Antenna Measurements

Near-field antenna measurements with an Unmanned Aerial Vehicle (UAV) require an accurate 3D position and 3D attitude information. In this paper, we estimate the position and velocity of the UAV, the quaternion that describes its attitude, the carrier phase integer ambiguities related to both the attitude and position, and the accelerometer bias with a Kalman filter. The raw measurements were obtained from the ANavS Multi-Sensor RTK module with its 3 Multi-frequency, Multi-GNSS receivers and a MEMS-based Inertial Measurement Unit (IMU). We used the UAV of AeroXess to validate our method and achieved a centimeter-level positioning accuracy in both static and kinematic conditions.