Active defense exo-atmospheric adaptive sliding mode guidance law in three dimensions

The problem of ballistic missile middle course penetration is investigated, and a guidance law named active defense adaptive sliding mode guidance law (AD-ASMG) is proposed. First, the three-dimensional relative motion equations of the three bodies-target, the intecepting missile the and defending missile are derived. Second, using the Lyapunov stablility theory, the guidance law is derived based on the triangle intecep-ting guidance strategy. Using the guaidace law two objectives can be achieved simultaneously, which are keeping the defending missile on the line connecting the target to the intercepting missile and nullifying the defending missile's line-of-sight rate to the intercepting missile. Finally, considering the fact that the thurster can only output the constant force, a pulse width modulation (PWM) controling method which accounts the dynamics of the thruster, is designed to get the variable equivalent force required by the guidance law whose output guidance command is variable. Simulation results show the high performance of the guidance law. ©, 2014, Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics. All right reserved.