A guidance law with finite time convergence considering autopilot dynamics and uncertainties

Taking into consideration both the autopilot dynamics and uncertainties, this paper proposes a finite time convergent guidance law for homing missile to intercept a maneuvering target. Firstly, an exact observer (differentiator) is employed to estimate the target maneuvers in finite time. Then, a finite time convergent guidance law is designed based on the existing finite time sliding-mode control theory. It is proved that the line-of-sight (LOS) angular rate converges to zero in finite time under the proposed guidance law. Compared with the existing finite time guidance laws, this guidance law can compensate for the effects of the autopilot dynamics and uncertainties, and the information used for feedback control is much easier to obtain. Finally, simulation results show that our scheme, as a finite time convergent algorithm, has strong robustness to bounded disturbances.