Bearing‐Based Moving Target Fencing Control for Multiple Underactuated Autonomous Surface Vehicles With Fixed‐Time Differentiators

ABSTRACT This paper addresses the moving target fencing (MTF) control issue of multiple underactuated autonomous surface vehicles (ASVs) in GPS‐denied environments. Existing solutions often rely on global positioning and target velocity measurements, limiting their applicability in engineering applications with sensor constraints. To overcome these challenges, a fixed‐time bearing‐based MTF control method is proposed. First, a target velocity estimator (TVE) reconstructs the target's velocity using only relative bearing and self‐velocity measurements. Furthermore, by unifying bearing rigidity theory and fixed‐time control, the algorithm ensures predictable convergence of fencing errors within a fixed time while maintaining safe inter‐vehicle distances, eliminating dependence on GPS or external localization systems, even under strong nonlinearities and coupled characteristics inherent to underactuated ASVs. It is worth emphasizing that a fixed‐time differentiator (FTD) is designed to rapidly estimate velocity derivatives while maintaining robustness against noise and disturbances without computational complexity or parameter‐sensitivity issues plaguing traditional methods, ensuring accurate signal tracking within a fixed time. Theoretical analysis proves all error signals converge to a compact set near zero within a fixed time. Finally, the “SpiritShark” ASV is designed with a modular approach. The effectiveness, robustness, and practicality of the proposed controller are validated through field tests conducted with the “SpiritShark” ASV, offering potential solutions for complex maritime missions.