Collision risk (CR) assessment is necessary for avoiding collisions with other ships. The CR can be used to make decisions on collision avoidance. In this respect, the ship domain and the closest point of approach (CPA)-based methods have been proposed to assess the CRs. However, the ship domain method is limited in terms of the quantitative calculation of the CR, whereas the CPA-based method does not guarantee reliable collision avoidance. In this study, an improved method is proposed for the quantitative calculation of the CR in ship navigation that combines the advantages of two existing methods. The proposed method calculates the CR using the CPA and defines the ship domain as a critical value of the CR to ensure reliable collision avoidance. In this process, the CR value of another ship on the boundary of the ship domain is calculated as 1, which implies that collision occurs, and the coefficients for the CR calculation are adjusted considering the distance from the ship domain. Furthermore, the manoeuvring performance and the heading angle of the ships are considered in the calculation of the CR. To evaluate the proposed method, it is applied to various examples, including a comparison with previous methods. The results show that the proposed method can be used to obtain a quantitative CR for collision avoidance.

中文翻译：

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基于CPA和船域的船舶航行避碰碰撞风险定量计算方法。

为了避免与其他船舶相撞，必须进行碰撞风险（CR）评估。CR可用于制定避免碰撞的决策。在这方面，已经提出了基于船域和最近进近点（CPA）的方法来评估CR。但是，船域方法在CR的定量计算方面受到限制，而基于CPA的方法不能保证可靠的避免碰撞。在这项研究中，提出了一种改进的方法，该方法结合了两种现有方法的优点，用于船舶导航中CR的定量计算。所提出的方法使用CPA计算CR，并将船域定义为CR的临界值，以确保可靠地避免碰撞。在此过程中，在该船域边界上的另一艘船的CR值计算为1，这意味着发生碰撞，并且考虑到距船域的距离来调整CR计算的系数。此外，在计算CR时要考虑船舶的操纵性能和航向角。为了评估所提出的方法，将其应用于各种示例，包括与以前的方法进行比较。结果表明，所提出的方法可用于获得定量的CR，以避免碰撞。