A METHOD FOR FORMALIZING THE DECISION-MAKING PROCESS FOR PREVENTING DANGEROUS SITUATIONS IN THE E-NAVIGATION SYSTEM

The study aims to improve the safety of ship traffic by improving the methods of formalizing the decision-making process for preventing dangerous situations in a single e-navigation concept. The goal is achieved by a clear statement of the problem and the choice of appropriate approaches to its solution. The main stages of the decision-making cycle performed by the navigator in collision prevention are analysed. Particular attention is paid to the operations performed at the decisionmaking stage on the further movement of the vessel. The ship's movement plan is described by models of elementary behaviour, each of which consists of elementary actions represented by a set of fuzzy logic rules for performing a certain subtask. The structure of a system that implements the behavioural approach to decision-making by a navigator is proposed. Emphasis is placed on the need to coordinate vessels when deciding to plan a route based on models of elementary behaviours, and a method for coordinating the planning of the vessel's trajectory is developed. The sequence of stages of the method for coordinating the planning of the ship's trajectory is performed cyclically until the target point of the route is reached. At each stage of the vessel's movement, the navigation obstacles and other vessels entering the area of interest of the navigator are monitored and potential hazards from them are identified. A method for tracing the vessel's movement and existing vessels in the navigator’s interest area has been developed, which allows for predicting the location at subsequent moments and identifying the coordinates of the conflict site where a situation of dangerous proximity occurs. To formalize the areas dangerous for vessel traffic, a method for generating a map of navigational hazards and conflict situations in the navigator’s interest area has been developed, based on a modified method of potential fields. To formally describe the space, only the concept of a potential function is used to represent the space as a matrix of values. The most significant scientific result is the proposed approach to solving the problem of supporting the decision-making of a navigator based on a combination of methods using fuzzy logic and allowed domains, which allows obtaining options for actions that ensure the safety of ship movement in a dangerous situation. Keywords: ship, navigator, collision, navigation situation, navigation systems, e-navigation, tracing method, navigation hazard, navigation hazard map