Terminal and Boost Phase Intercept of Ballistic Missile Defense

A new homing guidance and estimation algorithm for both terminal and boost phase intercept of the ballistic missile defense is proposed. The objectives of the algorithm are to estimate the engagement state in the presence of unknown target acceleration and guide the interceptor to hit the target based on the state estimate. The algorithm, derived by applying the linear-exponential-Gaussian (LEG) difierential game with difierent information patterns, is the integration of a fllter in cascade with a guidance law. In a certain limit of the LEG difierential game, the guidance law is equivalent to the classic game-theoretic guidance law determined based on the anticipated worst possible target acceleration. The fllter is determined by blocking the dynamic efiect of the target in the target acceleration direction. It is completely difierent from the traditional flltering techniques which estimate the target acceleration based on certain target models. The algorithm is demonstrated in numerical examples with the hit-to-kill capability against ballistic missiles in the terminal and boost phases.