ESO-based Guidance Law With Impact Angle Constraint for Maneuvering Targets

Abstract

In order to meet the requirements of impact angle constraint,a guidance law considering the second-order dynamics of missile autopilot was designed. A guidance system model with impact angle constraint considering the second-order autopilot dynamics was established. The super-twisting algorithm was used to improve the extended state observer. A super-twisting extended state observer was proposed to estimate the target acceleration. A nonsingular fast terminal-sliding-surface with impact angle constraint was selected. Combined with dynamic surface control,a new guidance law was proposed. The guidance law can achieve global finite-time convergence of the system states and compensate the autopilot dynamics. The comparison of simulation results shows that the proposed observer has high estimation accuracy. The proposed guidance law can achieve finite-time convergence of line-of-sight angular rate and impact angle,and it has better guidance performance.