  This paper presents a novel conflict resolution strategy for autonomous
surface vehicles (ASVs) to safely navigate and avoid collisions in a
multi-vessel environment at sea. Collisions between two or more marine vessels
must be avoided by following the International Regulations for Preventing
Collisions at Sea (COLREGs). We propose strategy a two-phase strategy called as
COLREGs Compliant Conflict-Resolving (COMCORE) strategy, that generates
collision-free trajectories for ASVs while complying with COLREGs. In phase-1,
a shortest path for each agent is determined, while in phase-2 conflicts are
detected and resolved by modifying the path in compliance with COLREGs. COMCORE
solution optimises vessel trajectories for lower costs while also providing a
safe and collision-free plan for each vessel. Simulation results are presented
to show the applicability of COMCORE for larger number agents with very low
computational requirement and hence scalable. Further, we experimentally
demonstrate COMCORE for two ASVs in a lake to show its ability to determine
solution and implementation capability in the real-world.
