Three-dimensional optimal sliding mode guidance with impact angle constraint

For issues that external uncertain disturbances and parameters perturbation can result in low guidance accuracy as well as poor robustness in traditional terminal phase, an optimal sliding mode guidance law with impact angle constraint was proposed. Firstly three-dimensional mathematical model of missile-target relative motion was established based on point mass assumption, then linear quadratic regulator with differential Riccati equations was adopted to meet the terminal impact angle while sliding mode control used to augment guidance robustness. The proof of Lyapunov stability and simulation results show that the combined three-dimensional optimal sliding mode guidance law can satisfy desired performance index and ensure high accuracy as well as strong robustness.