Ship Domain Research Based On AIS Data

In this thesis, the ship domain is researched based on the ship traffic information from AIS (Automatic Identification System, referred to as AIS) data of Qiongzhou Strait.AIS can be understood as a large-scale wireless LAN network and ship-related data transported within it. The ship-related data is the AIS message, it can also be known as the AIS report. First, analyses the type of AIS report, gets the ship traffic information from AIS data of Qiongzhou Strait and inserts it into database by writing C++program. The ship traffic of Qiongzhou Strait can be replayed on the ship traffic information database. By using the spherical geometry calculation method, the ships’movement relation can be calculated, which also be inserted into the database. Based on the regulations for preventing collisions at sea and set value of ships’movement relation, the encounter and avoidance information of motor vessels in navigation have been extracted. Then, taking into account the relationship of Ships’initial Closest Point of Approach (referred to as CPA) and avoidance behavior, using the fuzzy set theory, the concept of "Degree of Collision Avoidance"(referred to as DCA) is proposed, which can quantify the avoidance behavior of ship. Last, as the data of CPA and avoidance behavior are known, the statistical distribution of DCA on the two-dimensional plane, which is stand-on ship centered, can be got. Then draws the curve line of ship domain under different DCA value, fit it, and model the ellipse ship domain.The size of Qiongzhou Strait’s ellipse ship domain:major axis is2.17n mile, minor axis is1.77n mile. The centered ship is located in the rear of the ellipse’s center, right about16°, and the distance is about0.42n mile. The head of centered ship turns left about24°.The information of ship traffic is achieved from AIS data and inserted into database, which is used to study the ship domain. For the boundary of ship domain is unclear, the concept of DCA is put forward by quoting the fuzzy set. The application of AIS is expanded and the content of ship domain study is enriched.