A review of berthing technology for intelligent ships

With the continuous development of the global shipping industry, port waters have become increasingly busy and congested due to the growing number of ships, intensive traffic interactions, and the spatial constraints of areas. Compared with navigation in open waters, ship maneuverability is more restricted during port operations, while the effects of wind, waves, currents, shallow water, and other environmental disturbances become more significant. These characteristics increase the operational complexity and safety risks associated with ship berthing and may further affect the safety and efficiency of the maritime transportation system. At the same time, inefficient berthing operations can result in longer turnaround times and reduced overall efficiency of port management. Therefore, the development of high-level intelligent ships equipped with autonomous berthing capabilities is regarded as an important way to improve ship navigation safety, enhance operational efficiency, and support the intelligent transformation of ports and maritime transportation. Based on this background, a comprehensive review of existing research on autonomous ship berthing technologies is provided in this paper. The relevant studies are systematically summarized and discussed from four major aspects, including navigation situation perception and representation, autonomous decision-making, berthing path or trajectory planning and tracking, and berthing control methods. The characteristics, technical approaches, and limitations of current research are analyzed, and key issues requiring further investigation are identified. Overall, a systematic reference for future research on autonomous berthing is provided, and the further development of intelligent ship technologies and smart ports is expected to be facilitated.