Design of a robust guidance law via active disturbance rejection control

Focusing on the three-dimensional guidance problem in case of target maneuvers and response delay of the autopilot, the missile guidance law utilizing active disturbance rejection control (ADRC) is proposed. Based on the nonlinear three-dimensional missile target engagement kinematics, the guidance model is established. The target acceleration is treated as a disturbance and the dynamics of the autopilot is considered by using a first-order model. A nonlinear continuous robust guidance law is designed by using a cascaded structure ADRC controller. In this method the disturbance is estimated by using the extended state observer (ESO) and compensated during each sampling period. Simulation results show that the proposed cascaded loop structure is a viable solution to the guidance law design and has strong robustness with respect to target maneuvers and response delay of the autopilot.