Three-dimensional nonlinear H∞ guidance law

This paper proposes a novel three-dimensional missile guidance law design based on nonlinear H(infinity) control. The complete nonlinear kinematics of pursuit-evasion motion is considered in the three-dimensional spherical co-ordinates system; neither linearization nor small angle assumption is made here. The nonlinear H(infinity) guidance law is expressed in a simple form by solving the associated Hamilton-Jacobi partial differential inequality analytically. Unlike adaptive guidance laws, the implement of the proposed robust H(infinity) guidance law does not require the information of target acceleration, while ensuring acceptable interceptive performance for arbitrary target with finite acceleration. The resulting pursuit-evasion trajectories for both the H(infinity)-guided missile and the worst-case target are determined in closed form, and the performance robustness against variations in target acceleration, in engagement condition, and in control loop gain, is verified by numerical simulations. Copyright (C) 2001 John Wiley & Sons, Ltd.