Cooperative relative localization for moving UAVs with single link range measurements

This paper describes a method for estimating the relative pose of a pair of unmanned aerial vehicles (UAV) using noisy measurements from ranging radios and each aircraft's on board navigation system. In this method, there is no prior information needed about the relative pose of each UAV. During the estimation of the relative pose of two traveling UAVs, only a single range measurement between UAVs is needed at each location. To augment this limited information, motion is used to construct a graph with the range measurements and displacement in position over multiple locations. First, the analytical solution is derived for the pose from the constructed graph assuming the system is free of noise. Then, the relative heading and bearing are estimated from noisy range measurements and the displacement in position using nonlinear least squares. The sensitivity to the geometry and measurement noise are then analyzed for various trajectories. For this paper, the problem is analyzed for the two-dimensional case where the UAVs are traveling at equal altitudes.