A multi-ais message demodulation method suitable for satellite reception

Abstract

The invention devices a multi-AIS message demodulation method applicable to satellite reception. A demodulation processing method based on a slide window is adopted; the problem that the starting and ending locations of a signal frame are difficult in judgment resulted from multi-AIS message collision is overcome; a normal method of judging a frame header before demodulation is changed into a method of searching the frame header and a frame tail after obtaining a bit sequence through demodulation; therefore, the judgment difficulty of the frame header and the frame tail is greatly reduced; stack architecture assisted multi-demodulation control is adopted; under a condition of multi-AIS message collision, multi-way signals are demodulated successfully; the frames desired to be demodulated are all demodulated; and the demodulation method is low in operation complexity and is applicable to on-satellite real time processing.

Description

technical field [0001] The invention relates to a method for demodulating multiple AIS (Automatic Identification System) messages suitable for satellite reception, in particular to a multiple message demodulation method for low-orbit (LEO) satellites receiving AIS signals, which can be used in simple receivers Antenna in the spaceborne AIS receiving system. Background technique [0002] With the process of global economic integration and the rapid growth of maritime transportation and trade, it is urgent to create a system to realize the monitoring of global sea areas and improve the safety of maritime transportation. The traditional ground / sea AIS system has a short transmission distance and cannot realize long-distance eye surveillance. Satellite coverage is wide, and the space-borne AIS system can realize the monitoring of sea areas around the world, which has attracted the attention of various countries in recent years. [0003] One of the main technical difficulties i...

AI Technical Summary

Problems solved by technology

[0006] The technical problem solved by the present invention is: aiming at the deficiencies of the prior art, a multiple AIS message demodulation method suitable for satellite reception is provided, and under the condition that there are multiple message collisions in the AIS message received by the satellite, the frame error caused by the message collision is solved. It is difficult to judge the position of the head frame and the tail and the problem that the weak signal cannot be demodulated. Finally, the overlapping multi-channel AIS signals with different strengths are demodulated.

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