A 3-dimensional robust guidance law with impact angle constraint

A 3-dimensional robust guidance law is developed for impact angle control in this paper, using the linear quadratic optimal theory and the variable structure control methodology. In order to study the problem of the precision guidance, the motion of missile is decomposed in the diving plane and the turning plane. After the optimal guidance law is designed with terminal multi-constraint conditions of miss distance and impact angle, the sliding-mode correction terms are added to the guidance equations for the improvement of robustness. To reduce the chattering and energy consumption, the radius basis function neural network is applied to adaptive update of switching gains. Some simulations of the characteristic trajectories are implemented to demonstrate the performance of the robust guidance law and the results show that the guidance precision is less affected by disturbances such as signal jam, commands discontinuous, control system delay and target maneuver.