Guidance law incorporating second-order dynamics of missile autopilots

Based on the target-missile dynamics in plane and the second-order dynamics of missile autopilots, a new guidance law is designed using the dynamic surface control method. Some first-order low-pass filters are introduced into the design process to avoid the occurrence of high-order derivatives of line of the sight angular rate in the expression of the guidance law. Thus, the guidance law is easy to implement in practical applications. The proposed guidance law is effective in compensating the bad influence of the autopilot lag on guidance accuracy. In simulations of intercepting non maneuvering targets, targets with step acceleration, and targets with sinusoidal acceleration respectively, the guidance law is compared with the adaptive sliding mode guidance law which does not incorporate the dynamics of missile autopilots. Simulation results show that the guidance law still ensures an exact guidance result, even if the target escapes in a great and fast maneuver and the autopilot has a relatively large lag.