Time‐Varying Cooperative Guidance Law With Prescribed‐Time Convergence Under Bounded Disturbances With Unknown Upper Bounds

ABSTRACT This paper proposes two prescribed‐time terminal‐angle‐constrained guidance laws for three‐dimensional cooperative engagement in the presence of bounded disturbances with unknown upper bounds. The first law is an independent guidance law, and the second is a leader‐follower cooperative guidance law. Both laws are developed using linear time‐varying high‐gain feedback based on parametric Lyapunov equations. Along the line‐of‐sight direction, the tangential acceleration command is designed to enforce the prescribed arrival time. In the directions normal to the line of sight, the normal acceleration commands drive the LOS angles to their prescribed terminal values at the assigned time. For the cooperative case, a time‐to‐go consensus error is introduced to synchronize the remaining flight times of multiple vehicles, thereby achieving simultaneous arrival. The proposed design does not require prior knowledge of the disturbance upper bounds. Numerical simulations demonstrate the effectiveness and robustness of the proposed guidance laws.