Study And Design Of Space-based AIS Receiving System

The development of maritime transportation makes the maritime traffic network increasingly complex. In recent years, frequent oil spill accidents and Somali pirates have seriously affected the safety of maritime navigation, making people eager to find a way to understand maritime information in real time, Timely handling of maritime accidents, to protect the safety of navigation at sea. Space-based AIS system uses AIS receiver carried on the satellite to receive the signal, its observation scope is wider,how to construct a high performance AIS system has got the widespread concern of the researcher.The space-based AIS system is several times as wide as the shore-based AIS system and will face more complex problems than shore-based AIS systems. As the AIS system is based on the original AIS system developed on the basis of the original signal to prevent the conflict mechanism space-based AIS system is no longer applicable. The problem of signal collision is seriously disturbing the demodulation performance of space-based AIS system, and the space-based AIS receiver model is constructed rationally. Through the establishment of the receiver model to determine the satellite receiver program, so that the established demodulation algorithm can properly improve the performance of demodulation as the focus of this paper.Based on the "AIS Technology Research" project jointly conducted by the Institute of Space Research, this paper analyzes and studies the space-based AIS receiver module and detection probability analysis module in detail.First of all, this paper describes the research significance of satellite-borne AIS receiver system and the current research situation at home and abroad, aiming at clarifying the use of the receiver system and its simulation model.Secondly, the design scheme of satellite AIS receiver system is proposed. Based on the protocol and related technology, the original AIS signal source is verified and improved, including GMSK signal up-conversion, ship information crawling, satellite modeling of attitude receiving model, and modeling of different antenna satellite receiving models. Based on the JMLSE algorithm used in the demodulation algorithm, a detection probability calculation method based on power difference is proposed.Finally, the receiving system is simulated based on MATLAB, and the performance analysis of the system is carried out. In the simulation, the model of the receiving antenna is modeled for the antennas using different antennas. The receiver model is simulated and analyzed using the theoretical detection probability, the actual detection probability and the detection probability based on the power difference. The simulation shows that the model based on probability difference of power difference is better than the model based on the theoretical detection probability.