Design and realization of terminal guidance law for passive homing interceptors

It is of the essence for passive homing interceptors to acquire information required to implement guidance laws. In practical applications, the accuracy of obtained information directly exerts an influence on terminal guidance performance. In order to achieve hit-to-kill, a modified three-dimensional proportional guidance law designed to enhance observability of passive guidance of interceptors is presented in this paper. The dynamic model of three-dimensional interception based on Singer model and observation equation of infrared seeker are established. A real-time two-step estimator is adopted to estimate the states used to realize the modified guidance law, solving the problem of practical application of guidance law. Simulation results indicate that the modified guidance law in cascade with the real-time two-step estimator produces small miss distance, satisfying the requirement of terminal guidance accuracy of interception.