Estimation of the Collision Risk on Planned Route

In recent year, research on autonomous ships has progressed, and collision avoidance is one of the important tasks among them. Collision avoidance maneuvering includes judgment on uncertain events such as forecast of motions of other vessels. Therefore, it is effective to improve safety by navigating away from areas where a complicated encounter, in other words high collision risk, is likely to occur even when establishing the collision avoidance technology. Collisions tend to occur repeatedly in similar places. For this reason, areas where complicated encounter situations are likely to occur are considered to be areas where collisions occur frequently in the past. In addition, it is considered that the area in which many abnormal approaches of the ship occur is also an area where complicated encounter is likely to occur. From the analysis of AIS data, the ship close point is extracted and shown on the map. Also, in order to clarify the collision risk in the sea area, collision points and ship close points were converted into continuous distribution by kernel density estimation method and shown. Then, considering the time, the kernel density estimation method was extended to three dimensions so that the collision risk of the target area can be estimated. We used this to estimate the collision risk along the planned route. It was found that even on the same route the collision risk greatly differs depending on the time zone to be sailed. Even in existing vessels, the collision risk on the planned route can be obtained using this system. Therefore, it is possible to expect the accident prevention effect by allowing the operator to navigate by grasping the high-risk sea area.