AIS-based Ships Dynamic Supervisory And Its Application

AIS is a new type navigation and safety information system. It has been used since 1990. Modern communication, network and information technology are employed in it. Since 2000, the Maritime Safety Administration of China has been constructing AIS base station network. The framework of AIS network is formed. As a major port in our country ,the AIS base station network in Ningbo port has been completed .The producing background, current condition , structure and key technologies of AIS are described respectively in this paper.With the actuality of construction of AIS base station network in Ningbo port, there are three major problems have been sloved from receiving the message in base station to displaying the message in ECDIS:decoding of primitive message, transmission of AIS data and amalgamation of data from differente base stations.To have more cognition about AIS and made reference to some technologies, several algorithms have been advanced in every part.This paper mainly include:(1)The problem of decoding of primitive message was first to be settled.Three algorithms have been advanced: ASCII code transforms to 6 bit binary code;6 bit binary code transform to character code without referring to the coding table;the message ID can be judged by first ASCII code without coding,then improving the efficiency of coding.At last ,there algorithms can been transform to computer language.(2)The problem of looking up and making memory of a lot of data has been settled by using hash technology,then a feasible algorithm of amalgamation of data was been advanced base on actuality situation .(3) A software of communication with C/S model has been finished base on TCP/IPprotocol and passed the test,which settling the problem of communications from AISbase stations to server.(4)At last,AIS messages can be displayed in ECDIS,and match to production plan ofNingbo port.In this paper , there are several practice problems have been sloved,so it will help to design a ships dynamic supervisory system base on AIS system with several base stations.