OPTIMUM CONTROL OF AIR TO SURFACE MISSILES

Abstract : Design guidelines were developed to provide a basis for conducting design trades for a homing type air-to-surface missile with high terminal accuracy. Three basic homing guidance concepts, proportional, pursuit, and optimal guidance were evaluated on the basis of impact error. Two nominal trajectories were investigated. An optimal guidance law was developed for an ASM with realistic aerodynamic and sensor characteristics. This guidance law was based upon the use of a Kalman filter to obtain best estimates of the ASM state variable errors, and a control concept which minimizes the sum of the mean square impact error and the integral of a quadratic form of the autopilot control variables. A linearized differential equation program which computed the mean square impact error in the form of a covariance matrix deviation perpendicular to the nominal trajectory, was used for comparison of the guidance laws. A normal acceleration autopilot was designed to meet the mission requirements, and advanced bistable controller techniques were applied to obtain a quasi-adaptive autopilot which required no gain changes throughout the ASM midcourse and terminal phases. A limited state-of-the-art survey was conducted of homing and inertial sensors, and on-board digital computers suitable for a homing ASM.