Optimal Intercept Missile Guidance Strategies with Autopilot Lag

摘要

In the linear-quadratic pursuit-evasion game, the pursuer (interceptor) wishes to minimize the terminal miss,nwhereas the evader (target)wishes tomaximize it.Therefore, the optimal strategy of the interceptor is derived againstnthe anticipatedworst possible strategy of the target. If the interceptor has a lag, the current approach is to include thisnlag directly in the system dynamics, which are known to both players. In this problem formulation, the optimal costncould easily go to infinity, which means that the target will win the game. This is expected, because the target hasnknowledge about interceptor’s lag. To ensure the existence of an interceptor strategy, the weighting on the terminalnmiss has to be chosen small enough so that the optimal cost will remain finite. However, this manipulation preventsnthe target from maximizing the terminal miss and effectively constrains the target strategy. Therefore, theninterceptor strategy is derived against theworst-case target strategy that is not really theworst case. In this paper, it isnshown that this interceptor strategy performs poorly in realistic situations where the target tries to maximize thenterminal miss. Instead, two new interceptor strategies are derived against target strategies that are determinednwithout knowledge about the interceptor’s lag. These two optimal interceptor strategies improve the game-theoreticnguidance law for homing missiles by correctly taking into account the autopilot lag.