ABSTRACT
Unmanned ships have recently been studied mainly by Europe. For realization of such ship, a number of issues will be considered and one of the most important issues would be to avoid collisions with ships and obstructions floating at sea. It is essential to properly estimate a risk of collision for prevention of the collisions. There are a lot of indices for estimating risk of collision between two ships. However, it has not been validated whether such indices correspond to actual collision avoidance manoeuvres at sea. Therefore, the authors have analysed actual collision avoidance manoeuvres extracted from the recorded AIS data. Then, the authors propose a new method for evaluating collision risks based on two parameters, i.e. changing rate of relative bearing to a stand-on ship and distance between a give-way ship and a stand-on ship. In this paper, the method is described and validated based on comparison of two-ship encounter situations extracted from the AIS data and several simulation runs.
