Terminal Line-of-Sight Angle-Constrained Target Tracking Guidance for Unmanned Surface Vehicles

This paper investigates a Terminal Line-of-Sight Angle-Constrained Target Tracking Guidance (TLATT) for Unmanned Surface Vehicles (USVs). Dynamic target tracking technology has wide application potential in fields such as maritime rescue, countering illegal fishing, border and coastal defense. These tasks always necessitate the USVs intercepting the target with a specified Line-of-Sight (LOS) angle. In the majority of existing moving target tracking methodologies, the constraints associated with the terminal LOS angle have not been comprehensively studied. Addressing these issues, a target tracking guidance, constrained by the terminal LOS angle, is presented to guide the defender USVs in tracking a moving target in a specific direction. In the context of the general target tracking problem, the definitions of tracking errors have been precisely explained within the inertial frame. Then, the relative acceleration is derived by employing the back-stepping and mathematical induction. The course control strategy, formulated by incorporating both the relative distance and terminal LOS angle into the relative acceleration, has been developed in the horizontal plane. Distinct from existing approaches that employ switching logics to satisfy distance and angle constraints, our proposed guidance integrates angle constraints and target tracking into a unified framework, resulting in enhanced accuracy and robustness in dynamic tracking scenarios. The results of the simulations indicate that the proposed method can successfully restrain the terminal LOS angle as the relative distances decrease. The effectiveness of the proposed method has been verified via experimental results.