Nonlinear hoc robust guidance law for homing missiles

This paper proposes an H∞ robust guidance law for homing missiles with nonlinear kinematics in the homing phase. Unlike the conventional approaches where the trajectory of the target is often assumed to be known or needs to be estimated in real time, the proposed robust guidance law can achieve performance robustness in the absence of target's information and under the variations of the initial conditions of engagement. The most difficult and challenging task involved in applying the nonlinear H∞ control theory is the solution of the associated Hamilton-Jacobi Partial differential inequality (HJPDI). In this paper we show that the HJPDI of the missile guidance problem can be solved analytically with simple manipulations. The numerical simulations show that the H∞ robust guidance law exhibits strong robustness properties against the disturbances from target's maneuvers and the variations in initial engagement conditions.