Three-dimensional robust prescribed-time cooperative guidance for leader-follower strategy based on state observer: Simultaneous attack with impact angle control

This paper proposes a robust Prescribed-Time Cooperative Guidance (PTCG) method for leader-follower interceptors, enabling simultaneous attacks on maneuvering targets in Three-Dimensional (3D) space while satisfying impact angle constraint. Existing methods, such as fixed-time and finite-time approaches, due to their dependence on control parameters, are unable to arbitrarily predefine the convergence time and estimate the system states at a desired time. This limitation reduces their flexibility for application in complex operational scenarios, such as simultaneous attacks on maneuvering targets with specific constraints. To address this limitation, a robust Prescribed-Time Consensus Control (PTCC) is first designed for nominal nonlinear Multi-Agent Systems. Subsequently, a Prescribed-Time State Observer (PTSO) is introduced to derive leader states. Finally, after modeling the relative motion equations within the Line-Of-Sight (LOS) framework, using the proposed PTSO and PTCC approaches, and advanced Sliding Mode Control (SMC), robust guidance laws are presented in the LOS direction and perpendicular to it. These laws ensure that leader and followers simultaneously attack the maneuvering target at the prescribed-time with desired impact angles. Comparative simulations and experimental results validate the efficiency and effectiveness of the designed guidance laws.