Missile Variable Structure Guidance Law

A new variable structure guidance law(VSG), based on nonlinear relative kinematics, is proposed. The acceleration command input is determined considering the target acceleration as external disturbances, which are verified to satisfy the matching condition. The proposed guidance law only uses the information for the target acceleration bound; therefore the precise measuring of target acceleration during the maneuver is not required, namely, the robustness to target maneuver is archived. Like proportional navigation guidance (PNG), the new guidance law, which utilizes line-of-sight(LOS) measurement only, is simple in implementing.The Statistical Linearization Adjoint Method(SLAM) is utilized in the numerical simulations of this paper. The performance of the proposed guidance law is evaluated in three typical maneuver case: a constant target maneuver, a sinusoidal target maneuver, and a random telegraph maneuver. Simulations show that the variable structure guidance law yields much better performance compared to proportional navigation.Furthermore, nonlinear relative kinematics equations are derivated. The importance of collision course in guidance of homing missiles is elaborated, that is, the sufficient and necessary condition for a successful interception is the missile and target in the collision course.