The design of finite time convergence guidance law with angular constraint based on the ESO

Focusing on the problem that the guidance system exists model uncertainty and the disturbance caused by target maneuver in the terminal guidance program, a finite time converge guidance law with taking account of disturbance and terminal impact angle constraint is designed in this paper based on the extended state observer(ESO). Firstly, a finite time converge guidance law with taking no account of disturbance is designed. Then, to eliminate chattering and increase the observed precision, an extended state observer is designed based on the adaptive super-twisting control method. The disturbance in the guidance program can be estimated in the finite time by the designed ESO. The disturbance is compensated in the program of guidance law design. At last a finite time converge guidance law with taking account of disturbance and terminal impact angle constraint in the guidance program based the ESO is designed. The simulation results show the ESO designed in this paper can estimate the disturbance precisely and quickly in the finite time. For the maneuvering target, the guidance law designed in this paper has higher guidance accuracy and stronger robustness.