Multi-ship Encounter Situation Analysis with the Integration of Elliptical Ship Domains and Velocity Obstacles

: With economic globalization, ships tend to be larger and faster, and the volume of maritime traffic is increasing. S hips sailing in waters with dense traffic flow are easy to fall into compli cated multi-ship encounter situations and have a high risk of collision. Thus, it is crucial to conduct risk analysis in such situations. In this paper, a modified collision analysis method for detecting dangerous multi-ship encounters in ports and waterwa ys is proposed. The velocity obstacle algorithm is utilized to detect encounters. The model of the elliptic ship domain was integrated into the algorithm as the criteria. The Boolean operation was also used in the multi-ship encounter. A case study is conducted to illustrate the efficacy of the improved model, and a comparison between the existing method and the formal model is also performed. The results indicate that with the integration of the ship domain, the proposed method can effectively detect the encounters of multiple ships which are dangerous to collide.