Guidance Law for Multi-UAVs Collaborative Ground Target Tracking under Obstacle Environment

Multi-UAVs collaborative target observation and tracking is one of the typical applications of UAVs. In this paper, we focus on the study of multi-UAVs collaborative ground target tracking under obstacle environment. A UAV field for avoidance is given, and a UAV guidance law based on the Lyapunov guidance vector field is proposed to control the UAVs converging to the limit cycle over the target as well as avoiding the obstacles. Taking into account that the observation efficiency has a great degree of correlation with the observation angle, we design a phase control to maintain the phase angle between UAVs. Due to the speed limit of UAVs, the amplitude of the phase angle will increase when the speed limit is reached, and the observation efficiency will decrease. We use the standoff distance compensation strategy to reduce the amplitude of the phase angle. The simulation results show that the method we proposed in this paper can make the UAVs keep track of the target while avoiding the obstacle.