Study Of Key Technology Of Automatic Identification System(AIS)

With the rapid development of society and economic, the growing number of ships and traffic density have a serious impact on marine traffic safety and environment pollution. The marine accidents occur more and more frequently, which will result in a significant loss of life and property. AIS (automatic identification system) is a means of communication exchanging real-time data between ship and ship, ship and shore and it identifies target information which ensures the safety of maritime navigation at sea. With widespread application of the AIS on preventing collisions, maritime regulatory, information exchanging from ship to shore and other aspects at sea, application of Class B AIS impacting class A, appearance of spaceborne AIS and AIS information fusion technology are also becoming increasingly important in the future.With the financial aid of "Central Universities Basic Research Funds for Youth backbone Fund (ID:017166)", this paper studies communication performance of the AIS (automatic identification system), key technologies of spaceborne AIS application and information fusion of AIS and radar etc.The specific research work includes the following aspects.This paper makes oretical analysis on the network communication performance, slot collision rate, system capacity while AIS using SOTDMA and CSTDMA agreement, and builds mathematical analysis model and designs AIS communication performance simulation model based on the simulated VTS vessel traffic flow. This paper makes simulation analysis on performance of communication systems which includes both AIS Class A and Class B combined with the VTS simulator real-time traffic data flow.This paper proposes space-based AIS observation model based on the ships with AIS Class A and analyses the slot conflict probability of spaceborne AIS receiver based on probability theory and figure out the ship detection probability formula. Then it analyses the slot conflict probability of spaceborne AIS receiver using the monte carlo simulation method to verify the correctness and reliability of the proposed spaceborne AIS mathematical model.Then this paper proposes mathematical and correction model while the class A ships is detectting the spaceborne AIS signal in the situation that exists Class B AIS signal interference based on the basis of the above analysis.And this paper proposes an improved AIS and radar information fusion algorithm based on fuzzy correlation evaluation. The algorithm uses the time calibration algorithm based on least squares criterion. According to the characteristics of fuzzy factors in track correlation this paper chooses cauchy distribution function as a function of the degree of membership which is more flexible than normal and ridge distribution. Compared with other fuzzy association, the correlation algorithms improve effectively in computational complexity and the associated accuracy. On the premise of correct association this paper proposes the multi-sensor information fusion algorithm on the basis of the optimal weight stacking and recursive least square algorithm. This achieves AIS and radar information fusion algorithm with high accuracy and robustness. Then verify the algorithm on the project.The results show that the proposed method can fuse AIS and radar information more effectively.