Distributed observer-based fixed-time cooperative guidance law against maneuvering target

This paper presents a fixed-time cooperative guidance law for leader-following missiles, comprising one leader missile with the target seeker and several seeker-less follower missiles. The aim is to achieve a simultaneous attack on a maneuvering target at desired impact angles. First, a guidance law with impact angle control for the leader missile against a maneuvering target is proposed based on nonsingular fast terminal sliding mode (NFTSM) control algorithm. Then, the design of cooperative guidance law for the follower missiles is composed of two parts: along the follower-to-leader line of sight (LOS) direction, the guidance command derived from bi-homogeneous property is designed to ensure that the follower-leader ranges keep proportional consensus with the range-to-go of the leader missile, thus avoiding the estimation of time-to-go ((Formula presented.)); in the normal follower-to-leader LOS direction, considering the relative impact angle constraints which is determined by the leader LOS angle, the guidance command is proposed based on predefined-time sliding mode control method. What's more, a distributed fixed-time observer is designed for the follower missiles to compensate for unobtainable leader missile information. The fixed-time stability of the proposed methods is demonstrated using the Lyapunov theory and bi-homogeneous property. Finally, simulation results confirm the effectiveness and superiority of the proposed fixed-time cooperative guidance law with leader-following strategy.