Design And Performacne Simulation Of Ship Automatic Identification Network System

As the development of communication and computer technologies, the navigation is going ahead into the information age with a remarkable progress. In the world shipping, the number of ships with high speed or large scale is increasing and marine accidents usually occur in the narrow water area, which pose a threat to the lives at sea, property and marine environments. On the long-term study of the technology of navigation and security assurance, it is a precondition for the marine safety that ships can communicate and identify with each other. The universal automatic identification system (AIS) is a kind of new-style aids to navigation, and also is a ship network. It can guard the safe voyage and reduce the marine accidents by means of communication and collision avoidance. In the other hand, the AIS can combine with vessel traffic system (VTS) and strengthen the function of VTS, broaden the coverage of VTS, which is to the benefit of ship management.The AIS equipments have applied on board. It is need to establish the base facilities and AIS network in order to exert the functions of AIS. At present, many countries have taken up research on the AIS network, and set up some base networks. In our country the research is starting and the networks on the Yangtze Estuary and Pearl River Estuary are established. In the future, the AIS networks along the coast and Inland Rivers will seamlessly connected which can prove the ability of ship identification and make an effective management on the ships in our country.The universal automatic identification system is a new research finding in the domain of navigation and aviation, which is a landmark in the history of navigation. The proper use of AIS can improve the safety of navigation, put the axe in the helve of communication between ships and shores, and becomes the basis of digital marine transportation. The dissertation has developed the research work as follow on the study of some scientific and practical problems in the AIS network.(1) The dissertation makes a deep analysis on the working principle of AIS, and has a study on the hierarchical models, data transmission protocol, standard message format and message analytical method of AIS network. It accent on the discussion of slot-selection algorithm and slot reservation collision of Sef-Organised Time Division Multiple Access protocol. These are basis of AIS network research.(2) Presently in the domain of navigation, the research on the AIS network at a pre-theory stage. The AIS networks set up in many countries are confined to be a small AIS subnet. The dissertation compares the AIS network with mobile Ad hoc network, and makes a deep research on the AIS network performance by mean of theories and methodology and simulation tools of wireless network.(3) The dissertation puts forward a network model based on the central node according to the construction situation of AIS network in our country. Also the concept of service zone is introduced. It analyzes the slot status table and maintenance procedure in the service zone and AIS subnet, and brings forward a slot-selection algorithm of non-collision based on the central nodes.(4) On the study of assessment of network performance, the probability theory is used in the most documents on the assumption of ideal conditions. And wireless network experiments are substituted for the wired network (e.g. winsock program in TCP/IP network) in some documents. But there is a wide difference between them. The dissertation carries through the wireless network modeling on AIS by means of Network Simulation-2, and the amount of similarity between networks can be improved. The simulation experiments are conducted on the platform of Windows XP and Cygwin. The AIS network performance is analyzed according to the simulation results.(5) It is a trend that Intelligent Transportation System (ITS) applies in navigation. The existing technology of ECDIS, GPS/GIS, GMDSS and INMARSAT communication, with the improvement of AIS network, will be the foundation of marine intelligent transportation system. The dissertation brings forward the system models, analyzes the frame construction of MITS and puts forward the vessel dynamic monitoring system based on AIS, which can provide some references for the construction of coastal networksThe dissertation is supported by National Science Foundation of China (No.60172035,90304018), Specialized Research Fund for the Doctoral Program of Higher Education of China (No.20060497015).