A Cooperative Localization Method for Leader–Follower Multiple UAVs Using Continuous Relative Ranging Information

Cooperative localization(CL)utilizing multiple unmanned aerial vehides(UAVs)has become the current development trend and research hotspot.The tnditional distance-based CL method.typically uses principle of the spherical intersection to achieve UAV high-precision positioning.However,this distance based CL strategy requires several leader UAVs at the known positions.Thus,a cooperative localization method for leader-follower multiple UA Vs using continuous relative ranging information is proposed in this paper.Aiming at the UAV formation consists of a leader UAV node with the known position and at least a follower UAV that needs to be located.Using the Inertial short-time high-precision relative position constraint and the con-tinuous relative distance constraints with the leader UAV nodes,the closed-form solution of follower UAV's three-dimensional position can be obtained using spherical intersection prin-ciple.On this basis,we derive and construct follower UAV's position observation equation.The:developed strategy requires a single known position leader UAV node to realize high-precision CL,which can efctively solve the taditional distance-based collaborative location problem in case the number of leader UAVs is small.The simulation and experimental results demonstrate that the proposed method significantly improves follower UAV's positioning accuracy,and neglects the limitation of the traditional distance-based CL method on the number of leader UAV nodes at known positions.