An improved H∞ guidance law with terminal impact angle constraint for homing missiles

This paper presents an improved H∞ guidance law with the terminal impact angle constraint for homing missiles. By regarding target maneuvers as exogenous disturbances, the missile guidance problem is formulated as a nonlinear disturbance attenuation control problem. Furthermore, by introducing the Lyapunov stability criteria into guidance dynamics, not only the small miss distance and the specified impact angle are obtained, but also the H∞ attenuation level and the stability of the closed-loop system are guaranteed. The numerical simulation shows that the proposed method has the effectiveness and the robustness for homing missiles against both non-maneuvering targets and maneuvering targets.