OPTIMUM GUIDANCE WITH A SINGLE UNCERTAIN TIME-LAG

A disturbance attenuation problem that corresponds to optimal target i nterception is considered. In this problem the target's jerk is modele d as a finite energy disturbance, and the commanded acceleration of th e interceptor is the control variable, to which the actual acceleratio n is assumed to be related via a single uncertain time lag, The interc eptor's optimal strategy is obtained by considering an auxiliary distu rbance attenuation problem in which an additional fictitious disturban ce of finite energy, which corresponds to the uncertainty, is introduc ed. The resulting robust guidance law is compared to proportional navi gation and minimum effort guidance (with zero miss constraint) for sit uations with and without uncertainty and in the presence of heading er ror and various target maneuvers, The robust guidance law turns out to be the best choice in the setup we have worked with, which is linear, continuous time, and assumes perfect measurements of relative positio n, velocity, and accelerations of the interceptor and the target.