CONVERGENCE DANGER DEGREE ASSESSMENT BASED ON THE DYNAMIC SHIP’S SAFETY DOMAIN

Abstract

The problem of navigation safety is considered, in particular, the problem of assessing the degree of danger in a situation of ships convergence is studied. The hazard assessment of a ship-approaching situation is based on the safety domain as the minimum area around the ship that an oncoming ship should not enter. The existing safety domains are specified, the requirements for the safety domain are defined. The original configuration of the safety domain is proposed. The proposed safety domain is asymmetric and takes into account not only the requirements of the International Regulations for the Prevention of Collisions at Sea (COLREG-72), but also good maritime practice. In this case, the dimensions of the safety domain of a particular vessel are tied to the maneuverable characteristics of this vessel or, in a simplified form, to its dimensions. Thus, the ship’s safety domain defines the area around the ship within which it can safely make an emergency evasion maneuver from an oncoming ship. The position of the safety domain boundary is parameterized and depends on the value of one parameter, which is computationally convenient. In addition, it is noted that the border of the proposed security zone is smooth, which excludes jumps in solutions for different course angles of targets entry into this zone. The concept of a dynamic safety domain is proposed, the size of which can vary depending on the navigation area and weather conditions, which is especially important when the vessel moves in narrow spaces, channels and traffic separation systems, since it excludes the appearance of false alarms when the vessel, which moves in the opposite direction in its lane, enters into domain.