Adaptive Interception Strategies of Unmanned Surface Vehicle Defender for Coastal and Port Security

The rapid development of unmanned surface vehicles (USVs) in coastal and port security highlights the need for cutting-edge defense strategies against the highly potential attackers. Motivated by this issue, this paper presents an adaptive, state-machine-based framework for USV defenders for coastal area protection tasks. The main approach dynamically transitions between three operational states: patrol, intercept, and engage. During the interception phase, rather than going directly to the attacker's location, the proposed method calculates an adaptive blocking distance based on the real-time prediction of the attacker's trajectory and a radial approach mechanism ensures that the defender stably covers along the line between the center of the protected area and the attacker. This approach can effectively prevent the attacker from reaching the center of the protected area. Experimental results with 3D simulator (with realistic physics and water dynamic implementation) show that the proposed mechanism effectively intercepts the attacker's progress with shorter path length, competitive path smoothness performance, and shows potential for practical applications in coastal and port defense applications. This study contributes to developing intelligent control strategies for autonomous maritime defense systems.