A Real Time Dynamic Tracking System Of Vessel Based On GPS/AIS/VHF

As the development of modern shipping transportation, the sailors already recognize more and more deeply that a kind of device that can answer and identify automatically on the ships is very beneficial for safety of voyage, sea transportation control and surveillance the maritime environment. Automatic Identification System(AIS) was brought forward in this condition. AIS is a system which consists of satellite position, peg-top compass, log etc, it can transfer and receive information through VHF data link, and display nearby watercrafts position and navigational dynamic information on radar or electric chart.The Electronic Chart Display and Information System(ECDIS) and the AIS system is combined,so the ships information which comes from the AIS can be displayed on the Electronic Navigation Chart directly perceived through the senses. In the areawhere the signal of AIS was received,the position of vessels can be seen clearly,and the speed over ground,the course over ground and the rate of turn are shown on the Electronic Navigation Chart. The static data can be get to click each vessel simply. And the data which was received by AIS is saved in the database, so the information of the vessels could be played back. Therefore, the AIS real time tracking system of vessel which is combined by the technique of ECDIS and the AIS and the database has very big practical value.This paper introduces the construction and the key technique of AIS. The structure of AIS real time tracking system of vessel is designed,and the function of each module in the system is given according to the need. The protocol of AIS interface are the IEC 61162 protocol and ITU-R M.1371-1 protocol. The IEC 61162 protocol defines the method of connection,baud rate,the format of sentence and the communication character. The ITU-R M.1371-1 protocol defines the format and the means of each part of the encapsulation sentence in IEC 61162 protocol. The system parses IEC 61162 and ITU-R M.1371-1 sentences with Delphi which has the technique of Multi-Threading. It is making sure that the parsing of AIS data on the background is fast and in time. The SQL Server is used for the storing of AIS data. If the client want to play back the track of vessel,they can get the information from database using the connection of middle layer. This paper introduce the developing of dynamic Electronic Navigation Chart with component of MapX in Delphi simply. Extending the rage of AIS tracking with the technique of Internet is important to the practice.