Dual-Disturbance-Attenuation-Based Adaptive Guidance Law Against Maneuvering Targets With Practically Finite Time Convergence

The nonlinear disturbance observer is utilized to approximately estimate the target maneuvers. An adaptive algorithm with the feature of low-pass filter is developed to deal with the effects of the estimation error. The concept of practically finite-time stability is introduced to describe the finite-time convergence of guidance system with internal uncertainties and external disturbances. Then based on adaptive control method and terminal sliding mode, an adaptive guidance law is designed to drive the trajectories of the guidance system into a small set around the origin in finite time and to achieve an acceptable performance in the presence of the lag of actuator and external disturbance. It is proved that guidance system for the interception of maneuvering targets is practically finite time stable. Also, numerical simulation results are given to demonstrate the effectiveness of the developed guidance strategies for rapidly maneuvering target.