A novel sliding mode guidance law with finite-time convergent theory against maneuvering targets

This paper proposes a novel sliding mode guidance law with finite-time convergent theory against maneuvering targets with impact angle constraint and autopilot lag. To mitigate the external disturbance stemming from the target maneuver, an adaptive sliding mode disturbance observer(ASMDO) is used to estimate the target maneuver precisely. During the process of guidance law design, a fixed-time control theory is used during the reaching stage to guarantee the system state convergence time upper bound is relative to the flight time of the missile which can ensure that the stable time of the system state is less than the flight time to avoid large miss distance. Furthermore, the autopilot lag is approximated as a second-order link to be more practical in engineering. After the guidance commands are designed, a controller based on dynamic surface control is designed to track the designed acceleration commands. The Lyapunov method is applied to demonstrate the stability of the guidance law. Numerical simulations prove the effectiveness and progressiveness of the proposed guidance law.