AIS baseband signal receiving system and method suitable for spaceborne environment

A baseband signal and signal technology, applied in FM carrier system, modulated carrier system, transmission system, etc., can solve problems such as large interference, difficult maintenance, and limited coverage of shore-based AIS

Active Publication Date: 2022-07-01
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Due to the limited coverage of traditional shore-based AIS, and the high cost and difficult maintenance of base stations in some special areas, space-borne AIS can effectively solve the problems faced by shore-based AIS, but satellite channels have limited power, large interference, and signal Low noise ratio, the traditional AIS receiver has a simple structure, cannot resist large frequency deviation, and has low receiving sensitivity, so it is not suitable for AIS signal reception in the spaceborne environment

Method used

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  • AIS baseband signal receiving system and method suitable for spaceborne environment
  • AIS baseband signal receiving system and method suitable for spaceborne environment
  • AIS baseband signal receiving system and method suitable for spaceborne environment

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Embodiment 1

[0071] like figure 1 As shown, the present invention provides an AIS baseband signal receiving system suitable for a spaceborne environment, including a local signal generation module, a signal detection and frame synchronization module, a signal phase stripping module, a carrier synchronization module, and a frequency search and The maximum likelihood demodulation module for confidence calibration; the local signal generation module is used to use the 24bits training sequence and the 8bits start marker contained in the AIS message as the synchronization sequence of the signal, and perform GMSK modulation on the synchronization sequence to obtain local I, Q signals ; The signal detection and frame synchronization module is used to calculate the cross-correlation of the local I and Q signals based on the phase change to obtain the starting sample point of the signal; the signal phase stripping module is used to analyze the local signal according to the starting sample point of t...

Embodiment 2

[0080] like figure 2 As shown, the present invention provides an AIS baseband signal receiving method suitable for an on-board environment, and its implementation method is as follows:

[0081] S1. Local signal generation: The 24bits training sequence and the 8bits start marker contained in the AIS message are used as the synchronization sequence of the signal, and the synchronization sequence is GMSK modulated to obtain the local I and Q signals. The implementation method is as follows:

[0082] S101. Use the 24bits training sequence and the 8bits start marker contained in the AIS message as the synchronization sequence of the signal, and perform differential encoding processing on the synchronization sequence;

[0083] S102, using a Gaussian low-pass filter to smooth the phase path of the differentially encoded signal;

[0084] S103, performing integration processing on the smoothed signal;

[0085] S104, using GMSK modulation, take cosine and sine respectively for the si...

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Abstract

The invention provides an AIS baseband receiving system and method suitable for a spaceborne environment, belonging to the technical field of maritime communications, comprising a local signal generation module, a signal detection and frame synchronization module, a signal phase stripping module, a carrier synchronization module and a serially connected module. Maximum likelihood demodulation module based on frequency search and confidence scaling. In the present invention, the signal detection and frame synchronization part adopts the cross-correlation algorithm based on the phase variation to determine whether there is a useful signal and to determine the starting position of the signal; the carrier synchronization part uses the FFT algorithm to obtain the preliminary estimation of the frequency and phase; the demodulation part uses Frequency search, ML demodulation, confidence calibration, coherent demodulation with strong error correction. The spaceborne AIS signal receiver adopts this structure, which can resist large frequency deviation and have high receiving sensitivity.

Description

technical field [0001] The invention belongs to the technical field of maritime communication, and in particular relates to an AIS baseband signal receiving system and method suitable for a spaceborne environment. Background technique [0002] Ship Automatic Identification System (AIS) can automatically receive and send important information such as speed, position, and heading of ships. Therefore, AIS plays a role in avoiding collisions between ships, reducing average incidents, ensuring ship navigation safety, and promoting marine traffic management. important role. [0003] Due to the limited coverage of traditional shore-based AIS, and the high cost of erecting base stations in some special areas and difficult maintenance, the satellite-borne AIS can effectively solve the problems faced by shore-based AIS. Due to the low noise ratio, the traditional AIS receiver has a simple structure, cannot resist large frequency deviation, and has low receiving sensitivity, so it is ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B7/185H04L27/00H04L27/10H04L27/12H04L27/14
CPCH04B7/18513H04B7/18517H04L27/0014H04L27/106H04L27/12H04L27/14H04L2027/0026
Inventor 李桓朱继飞杨鍊王坚朱闲省
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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