Tracking Differentiation Guidance Law Based on Backstepping Control

This paper presents a tracking differentiation guidance law based on backstepping control method with the autopilot dynamics compensation. For improving the guidance precision, the methods of passively improving the guidance robustness and actively estimating the target maneuvering form are adopted. First, a three-dimensional decoupling guidance model considering the autopilot dynamics and the input saturation is proposed. Second, a generalized extended state observer is used to estimate the unknown normal acceleration of the line-of-sight. Third, tracking differentiators are designed to solve the problem of “explosion of items” in the process of the backstepping design for the third-order guidance system. The stability of the nonlinear guidance closed-loop system is analyzed by Lyapunov theory. Compared with the traditional dynamic surface control, the actual errors between the system state variables and the designed ideal control commands are adopted to improve the performance of the tracking control in backstepping design. The effectiveness of the guidance and the signal tracking is verified by the simulation.