A Highly Accurate Feedback Approximation for Horizontal Variable-Speed Interceptions

An improved feedback approximation of the time-optimal control strategy in a horizontal, variable-speed, air-to-air interception is presented. The improvements are achieved by reformulating the previously used multiple-time scale, forced singular perturbation model and by incorporating first-order correction terms in the control law. Comparison of the uniformly valid feedback approximation with the exact open-loop control solution shows a remarkable payoff accuracy, even for very short initial ranges. Consequently, the domain of validity of the feedback approximation is greatly extended, enhancing its attractiveness as an improved building block in future airborne implementations.