Design of three-dimensional finite-time guidance law for intercepting hypersonic vehicle

Traditional guidance method is difficult to ensure the interceptor's guiding accuracy in intercepting a hypersonic vehicle due to the vehicle's fast flight speed and high maneuverability. To reduce the relative velocity between the target vehicle and the interceptor, and lower the overload requirement of the interceptor, a three-dimensional head-pursuit sliding mode guidance law is presented. The guidance law adopts continuous fast double-power reaching law, which can ensure the convergence speed and weaken the chattering phenomenon caused by traditional guidance laws. Based on these, a three-dimensional head-pursuit adaptive sliding mode guidance law is designed to deal with the problem of unknown upper bound of the external disturbance. The guidance law can not only deal with this problem, but also can ensure the good characteristics of the first controller. The sliding mode guidance laws are proved by the theoretical perspective based on Lyapunov stability theory. Finally, the correctness and effectiveness of the methods are verified by numerical simulation.