An empirical ship domain based on evasive maneuver and perceived collision risk

Funding Information: The first author of this work is supported by the China Scholarship Council (Grant Number: 201606950009) and Marine Technology research group in Aalto University (9170094). This work is also supported by the National Science Foundation of China (NSFC) through Grant No. 52001237 and 52001241. The work has further received financial support from the Canada First Research Excellence Fund, through the Ocean Frontier Institute. This financial support is gratefully acknowledged. Besides, we thank the two anonymous reviewers for their very insightful comments, which have been very instrumental to improve an earlier version of this work. Publisher Copyright: © 2021 This paper introduced a new ship domain concept and an analytical framework. The ship domain takes the point of the ship’s first evasive maneuver as a basis and correlates it with the navigator-perceived collision risk level. The first evasive maneuver of a ship is detected based on the ship turning point identification and ship intention estimation. The available maneuvering margin (AMM) is utilized as a proxy to measure the perceived collision risk by the navigator. Interpreting the first evasive maneuver in terms of this AMM over a large sample of vessel encounters taken from automatic identification system (AIS) data finally enables an empirical estimation of the size of this ship domain. The method is applied to AIS data in the Northern Baltic Sea, and separate ship domains are constructed for the give-way and stand-on vessels with different maneuverability characteristics. Compared to the existing proximity-based ship domain, this ship domain explicitly incorporates the dynamic nature of the encounter process and the navigator’s evasive maneuvers. Several advantages of this proposed ship domain concept and limitations of the presented modeling approach are discussed. Finally, possible future applications are explained, including waterway safety assessment and navigational decision support systems to reduce ship-ship collision risk.