Impact Time Control Guidance Law for Guided Projectile Considering Time-Varying Velocity

A novel impact time control guidance law for guided projectile considering time-varying velocity is presented based on linearized relative motion model, optimal control theory and trajectory prediction algorithm. In the process of deriving the guidance law, a time-to-go estimation formula for guided projectile with time-varying velocity is also obtained. The proposed time-to-go estimation formula and guidance law are simulated, and simulation results show that the estimation formula has high accuracy in the case of small flight path angle, as the flight path angle increases, the estimation accuracy decreases. In the proposed guidance law, the time-to-go estimation is an independent part and can be replaced by a more accurate estimation algorithm when the guided projectile flies under large flight path angle, and the proposed guidance law can satisfy the constraints of miss distance and impact time.