A Single-Loop High-Order Sliding Mode Controller for a Missile Interceptor

The guidance and control (G&C) on a missile interceptor orchestrate the vehicle's functional subsystems to minimize miss distance. In contrast to the traditional cascaded G&C loop structure that handles the guidance and control separately, a single-loop and single control law govern the fin actuation. The high relative degree of a missile engagement scenario makes controller design more difficult. The use of higher order sliding mode differentiators mitigates the problem. The objective of this work is to develop a robust, high-order sliding mode controller that intercepts maneuvering targets using minimal information. Nonlinear pitch plane engagement kinematics and linear pitch plane missile dynamics are defined for controller development and simulation purposes. Through simulation the control law is shown to be simple and intuitive, only requiring relative normal velocity for state feedback, meaning it can work in a GPS-denied environment.