Three-dimensional hit-to-kill guidance law for direct thrust controlled interceptor

A three-dimensional hit-to-kill guidance law is designed for the direct thrust controlled kinetic kill vehicle to against maneuvering near-space hypersonic targets, which is based-on the Smooth Second-Order Sliding Modes (SSOSM) control law and Non-Homogeneous High-Order Sliding Mode Observer (NHHOSMO). The normal velocity of the Line-of-Sight (LOS) is chosen to be sliding variable based-on the principle of zero angular velocity of LOS. Decoupling between different channels is realized by regarding the coupling term of sight angular rate, the acceleration component of the maneuvering target to be uncertainties, which will be accurately estimated by the NHHOSMO. The feasibility of the guidance law is verified by simulation, where the Pulse-Width Modulation technical is used to implement direct thrust control.