Modern control theory for design of autopilots for bank-to-turn missiles

The state-space techniques of modern control theory are used to develop a methodology for the design of autopilots for bank-to-turn missiles. The methodology accommodates the gyroscopic and coriolis cross-coupling between the pitch and the yaw axes that result from the high roll rates that may be present. The design assumes that the roll rate is constant but not zero, and it results in an autopilot structure in which there are cross-couplings between the pitch and yaw channels that are dependent on the roll rate. The autopilot gains are also scheduled as functions of the dynamic pressure. A reduced-order extended Kalman filter with fixed gains is used to estimate the actuator states and the commanded acceleration. The performance of an autopilot designed by this methodology was evaluated in a six-degree-of-freedom simulation using the dynamics of a typical high-performance tactical missile. Excellent performance in terms of low miss distance and small sideslip is obtained.