Guidance laws design for trajectory tracking of UAVs carried by tanks

The unmanned air vehicle (UAV) can provide a wider field of view for tanks to improve their survivability. And an optimal guidance law that makes UAVs follow a circular trajectory around the tank is proposed by introducing a relative reference frame. The guidance law consists of two phases: the first phase is for surveillance orbit entry, in which the UAV enters the orbit from the direction that is tangent to the circular orbit around the tank; and the second phase is for orbit holding, in which the UAV tracking circular orbit even though the tank performs active maneuver. Mathematical methods are used to analyze the convergence of lead angles and acceleration in the first phase and the convergence trend of path errors in the second phase. Numerical simulations are performed to validate the proposed guidance law.