Abstract:An antenna near-field phase recovery algorithm requires an unmanned aerial vehicle (UAV) flying along a specific path and obtaining its position. A navigation scheme using the differential GPS module and visual sensor was designed according to the UAV flight requirements of the phase recovery algorithm.However, using conventional extended Kalman filter (EKF) with the time strategy designed in this scheme will cause the concussion problem. An improved adaptive EKF based on the Sage-Husa algorithm was then proposed to solve the problem, and the results were compared with those of the conventional extended Kalman filter by simulations and actual flight tests. The experimental results show that the improved adaptive EKF gets better performance in practical applications, makes the results converge to visual odometry data which are more reliable in the case of low GPS signal and meets the antenna measurement requirements of letting the UAV running along the trajectory and capturing the position data which makes the near-field shape recovery be viable at any pitch angle.