Multi-ship collision avoidance decision-making model considering operation conflict under COLREGs

When an officer on watch (OOW) faces the complex multi-ship encounter situations, choosing the appropriate decision could improve maritime safety and reduce navigation burden. However, the operation conflict under multi-ship encounter situation would make the decision much more complex. In this paper, based on COLREGs, the cooperative collision avoidance decision model is established to make the optimal decision in multi-ship encounter in iterative mode, so as to solve the problem of decision conflict among the ships. Firstly, the collision risk between own ship and target ships is determined by Distance at Closest Point of Approach and Time to Closest Point of Approach. Secondly, an objective function is established considering the COLREGs, ship drift and collision risk. Finally, the optimal decision is selected through the prediction mechanism. The results show that the collision avoidance model can ensure safety with lower steering frequency and shorter anti-collision time. The proposed model can provide reference and improve the efficiency in multi-ship encounter situations.