Fixed-time Guidance Law for Intercepting Maneuvering Targets with Impact Angle Constraint

Considering the problem of the missile for intercepting the maneuvering targets with the impact angle constraint, a novel adaptive fixed-time nonsingular fast terminal sliding mode guidance law (AFTNFTSMGL) is proposed in this paper. Firstly, a novel nonsingular fast terminal sliding mode (NFTSM) surface with fixed-time convergence regardless of the initial states is developed. Then, a modified AFTNFTSMGL is proposed based on the newly-defined NFTSM, where the unknown upper-bound of the unknown external disturbance caused by the target acceleration is estimated online by an adaptive law. The globally fixed-time stability of the proposed guidance law is derived with the Lyapunov methodology. Finally, simulation results show the effectiveness of the proposed guidance law.