Finite-time sliding mode control based 3D guidance law with impact angle constraints

To deal with the guidance problem of missile for intercepting ground fixed targets, a three-dimensional finite-time sliding mode control based guidance law is proposed in this paper. It is proved by the Lyapunov theory that the guidance law can steer the missile to intercept target with the desired impact angles in both azimuth and elevation. The guidance law has four advantages. First, model decoupling or model linearization is not needed in this work; second, the impact angles in both longitudinal and horizontal can be controled; third, the guidance command can be analytically derived; fourth, the closed-loop system is insensitive to external disturbance as well as parameter uncertainty. The simulation results show that high terminal accuracy and good robustness can be achieved by the proposed guidance law.