The application of sliding mode control on terminal guidance of interceptors

In this paper, we discussed the terminal guidance problems of ballistic missile interceptor from dynamical aspect. We assume that the interceptor is equipped with solid propellant system and orbit control engines can provide stationary continuous thrust or small pulse thrust in the direction vertical to the line of sight(LOS), and the target has some uncertain maneuver. Firstly, we build the relative motion equation between missile and target. Then terminal guidance law is designed by use of sliding mode control theory. To realize this terminal guidance law, we also designed the switch law of orbit control engines. Finally, Simulation results show that the intercept accuracy with slide mode guidance law in this paper is better than with pure proportional guidance law for targets with maneuverability. They also show that the LOS rate is about to zero in terminal phase for maneuver target and the switch law can ensure to realize the guidance law.