All-digital receiving method for satellite-borne AIS

Abstract

The invention provides an all-digital receiving method for a satellite-borne AIS.The method comprises the steps that a signal processed through radio frequency digitization and a local carrier are subjected to orthogonal frequency conversion and then filtered to acquire mixed baseband signals, and the mixed baseband signals are separated; burst detection is performed on separated one-way signals; after a frame header is detected, frequency offset estimation is performed, and frequency offset compensation is performed on the baseband signals on the basis of a frequency offset estimation result; a frame header sequence is selected as an input signal for symbol timing synchronization to acquire a symbol timing error estimation value, and optimal sampling point data is interpolated according to the symbol timing error estimation value; information demodulation is performed on the optimal sampling point data by adopting an incoherent Viterbi demodulation algorithm, a bit information sequence is verified on the basis of a cyclic redundancy check code, and an optimal sampling point sequence of a frame header symbol period and the frequency offset, the amplitude and the initial phase of the verified bit sequence are estimated; a demodulation signal is recovered on the basis of frequency offset, amplitude and initial phase estimation values; the recovered strong signal is subtracted from the separated mixed baseband signals.

Description

technical field [0001] The invention relates to a wireless digital communication technology, in particular to a satellite-borne AIS all-digital receiving method. Background technique [0002] Ship Automatic Identification System (AIS) is a kind of ship navigation equipment based on self-organizing time division multiple access (SOTDMA) communication protocol, which transmits and receives ship dynamics, static information, navigation information and safety information. During the navigation of the ship, collision avoidance can be effectively avoided by receiving the AIS signals issued by each other. The International Maritime Organization stipulates that all international voyage ships of 300 gross tonnage and above, and non-international voyage ships of 500 gross tonnage and above, as well as all passenger ships, must be equipped with this system. The International Telecommunication Union (ITU) also allocates two channels to AIS in the VHF frequency band, namely CH87B (AIS1,...

AI Technical Summary

Problems solved by technology

The same type of spaceborne AIS receiving device and method has not been found in existing patents

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