Predefined‐Time Convergent Guidance Law With Impact Time Constraints

ABSTRACT For the existing impact time guidance laws based on finite‐time and fixed‐time stability theory, the upper bound of the convergence time depends on initial conditions and control parameters, which may result in degraded impact time accuracy and interception performance. Hence, this paper proposes a predefined‐time convergent impact‐time‐constrained guidance law against the stationary target in the planar scenario. Based on a predefined‐time stability theory and an existing Lyapunov‐based guidance law, a feedback bias term is derived and then utilized in the design of the guidance command. The key feature of the proposed guidance law is that the predefined convergence time of the impact time error is independent of initial conditions and control parameters, thereby improving the convergence performance and enabling the desired impact time to be achieved more accurately. Finally, the theoretical analysis and numerical simulations are presented to verify the effectiveness and robustness of the proposed guidance law.