Optimal formation of unmanned aerial vehicles for minimizing localization error — A two-dimensional case

Robust 3D-Trajectory and Time Switching Optimization for Dual-UAV-Enabled Secure Communications

“…where d min is the minimum anti-collision safe distance. Since the UAVs need to correct the positioning error to successfully arrive at the final location in practical scenarios [39], [40], the accumulated errors on the horizontal and vertical directions need to meet the following constraints:…”