Research And Implementation Of Automatic Identification System

Since the21st century, human beings are stepping into the era of information science and technology. Information has become one of the most valuable resource for human in recent years. It makes the amount of trade between countries rising these year that the economic globalization is developing rapidly. Therefore, the number of vessels is also increasing, which has resulted in the maritime transport environment are getting more and more complicated. The shore-based maritime supervision technology is unable to meet the demand of maritime management nowadays. Space-based AIS that carry the AIS receiver on the satellite to monitor the ships in the vast sea is the new maritime management system in recent years, which is able to greatly improve the efficiency of maritime management.The research of space-based started in the foreign country very early, so there has been some mature research results. By contrast, there is still a big gap between China and foreign country in this field. The data that satellite received is the basis of in-depth research of space-based AIS. But the cost to obtain the data in domestic is high, while the existing space-based AIS simulation platform is lack of authenticity and accuracy. For these problems, the thesis designed and implemented a space-based AIS simulation platform.First, the thesis described the characteristics and research status briefly, and illustrated the significance of the research of the simulation platform.Then, the thesis designed and implemented a space-based AIS simulation signal source, which is based on the characteristics of satellite channel and related standard of AIS. And the theory of vessels detection probability formula is deduced, which verified the accuracy of the analog source. The simulation platform is set up based on the simulation signal source.Then, the thesis analyze the system using the platform. The vessels detection result of simulation shows that the performance could be improved significantly if the demodulation algorithm is able to demodulate the2-level collide signals and the3-level collide signals correctly.Finally, the thesis compared the performance of different adaptive equalization algorithm using the simulation platform, proposed a PSO signal equalizer and optimized the method of inertia weight adjustment which could increase the convergence rate of algorithm. The simulation result shows that the PSO algorithm is able to reduce the demodulation bit error rate of the space-based AIS signal and enhance the performance of space-based AIS.