A guidance law with finite time convergence accounting for autopilot lag

By considering the dynamics of a missileʼs autopilot as a first-order lag, a guidance law with finite time convergence is designed based on target–missile relative motion equations. It is rigorously proved that states of the guidance system converge to a sliding-mode in finite time and the line-of-sight (LOS) angular rate converges to zero in finite time under the proposed guidance law. Simulation results show that the guidance law is robust against target maneuvers and is able to compensate for the autopilot lag.