Spatio-temporal cooperative guidance law with switching topologies against unknown maneuvering target: A gain-tunable prescribed-time method

For the problem of multiple missiles attacking an unknown maneuvering target, this paper proposes a spatio-temporal cooperative guidance law, whose convergence time can be specified freely regardless of the initial states based on a gain-tunable prescribed-time stability criterion. This criterion not only enables switching between the time-invariant gain predefined-time stability method and the time-varying gain prescribed-time stability method by tuning the gain, but also eliminates the infinite gain issue of the latter without compromising the error convergence performance. Firstly, without requiring a priori knowledge of the maneuvering target, prescribed-time disturbance observers are constructed to guarantee prescribed-time convergence of the estimation errors on target acceleration components. Secondly, a distributed temporal cooperative guidance law is designed to achieve prescribed-time consensus on impact times of multiple missiles with switching topologies. Thirdly, a nonsingular sliding mode surface is presented to develop a spatial cooperative guidance law, enabling the line-of-sight angle of each missile to converge to a predetermined neighborhood around the desired value within a prescribed time. Finally, the effectiveness of the guidance law and its robustness against communication topology switching are verified through simulations.