Abstract: In order to achieve higher interception precision, in the process of terminal guidance, the guidance law must ensure that the line of sight (LOS) angular rate converge to zero rapidly. To improve the performance of the guidance law, a variable structure guidance law with double closed-loop filters is studied while assuming the unavailable information as bounded time-varying uncertainties. The method presented here is able to make the LOS angular rate and its first order derivative converge to the sliding mode in a finite time, realize the acquisition of equivalent control accurately and overcome the influence of disturbance. By using the high-order sliding mode, some related theorems are proved again, while the proving process is simplified, the conclusions of the theorems are reinforced and the preconditions are less rigorous. Finally, the effectiveness of the proposed approach is validated by numerical simulation.

Key words: finite time stability, closed-loop filter, variable structure control, guidance law, sliding mode control