Trajectory Planning for Moving Target Tracking from a UAV

This paper presents an optimal control-based solution to the problem of standoff tracking of a moving ground target using a single UAV with limited motion and sensing capabilities. The UAV is a tactical fixed-wing aircraft equipped with a gimbaled camera. The resulted optimal trajectory minimizes the weighted sum of the control effort and the slant range error between the UAV and the ground target. The roll angle is used as the control variable. Firstly, a receding horizon method, which requires a short amount of future ground target movement knowledge, is proposed to solve the trajectory planning problem. Secondly, a more efficient approach is evaluated by discretizing the continuous roll angle for a real-time and easy on-board implementation. Numerical simulations are performed to verify the feasibility and benefit of the discretized trajectory planning approach.. The results show trajectory solutions that are similar to the optimal ones with significantly less computational effort, exhibiting robustness to wind and disturbances. When contrasted with other guidance strategies, it outperforms heuristics solutions since it takes benefits of future target location knowledge.