Midcourse guidance for a short-range attack missile using error compensation

Abstract

A midcourse guidance law is developed for a short range attack missile of the SRAM I1 class which has a very high thrust-teweight ratio. The optimal control formulation is to minimize the flight time from a low altitude, subsonic launch to a fixed ground target 100 300 nm from the launch aircraft at any azimuth. An approximate optimal guidance law is developed by neglecting the aerodynamics and creating burnout conditions which enable the zero angle of attack coast to get close to the target. Simultaneously, error compensation terms are included in the state differential equations and final conditions that lead to a control law which can be tuned to improve the performance of the missile and enable it to hit the target. The error compensation weights are obtained by solving the true optimal control problem numerically. In practice, weights could be stored for each target range and azimuth and obtained from a table.