Design of an observer-based sliding mode guidance law with finite time convergence

Considering the terminal guidance issue that the missile and the target were relatively moving in a plane, two major factors of the target's maneuvering and missile's dynamic delay characteristics were considered. Then, two sliding mode guidance laws with asymptotic convergence and finite time convergence were respectively designed. Firstly, selecting the linear sliding manifold with dynamic sliding mode variable, a sliding mode guidance law with asymptotic stability was proposed. After that, a linear sliding mode manifold with finite time convergence was further selected on the basis of dynamic sliding mode variable, and a sliding mode guidance law with finite time convergence was presented. In the process of implementing the guidance law, an inhomogeneous disturbance observer was employed to estimate the unknown disturbance of the system. Finally, two cases for the different target acceleration and selecting different dynamic delay parameters were considered. The results show that simulation comparison results are provided to demonstrate the effectiveness and the realizability of the proposed two sliding mode guidance laws from.