Cooperative 3-D relative localization for UAV swarm by fusing UWB with IMU and GPS

Abstract

A real-time 3-D relative position estimator is presented for fixed-wing UAV swarm system in formation flight, using measurements from IMU, compass, GPS, and a set of UWB ranging radios. Instead of using stationary UWB anchors to provide 3-D coordinate and fusing it with IMU, the estimator uses UWB measurements for the construction of a non-convex function, and calculates the global optimum of the non-convex function to get position estimation, while the GPS positions are used to provide bearing information. Actual flight experiments with seven fixed-wing UAVs are conducted outdoors, and the experimental results indicate that the proposed scheme achieves lower distance estimation error between neighbor UAVs compared to traditional GPS/IMU/UWB fusing algorithm using EKF.