Three-dimensional guidance model and guidance law design for head pursuit interception

A HP (head pursuit) guidance law is proposed to eliminate the perturbation of interceptor detection induced by aerodynamic heating. The guidance law positions the interceptor ahead of the target on its flight trajectory, and the speed of interceptor is required to be lower than that of the target. A HP nonlinear guidance law is presented based on the second-order sliding mode control theory, considering the kinematics of interception and the uncertainty of target acceleration. A special observer is designed to estimate the target acceleration. Simulation results verify the rightness of the three-dimensional guidance model and the effectiveness of the guidance law.