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System and method for decoding automatic identification system signals

  • US 8,374,292 B2
  • Filed: 10/29/2010
  • Issued: 02/12/2013
  • Est. Priority Date: 06/08/2007
  • Status: Active Grant
First Claim
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1. A method for producing validated decoded Automatic Identification System (AIS) message segments from a plurality of AIS signals wherein a plurality of AIS signals are received at one or more satellites in space and pre-processed to produce digital input data corresponding to the received plurality of AIS signals, the method comprising:

  • processing the digital input data by correlating the digital input data with a plurality of predefined signals having different Doppler offsets to compute a plurality of corresponding correlation signals, wherein the plurality of predefined signals are generated by applying the different Doppler offsets to a predetermined AIS code sequence, and scanning the plurality of correlation signals for amplitude peaks exceeding neighbouring amplitude peaks by a predetermined amount in order to identify one or more candidate AIS message signals;

    determining corresponding Doppler offset estimates and arrival time estimates for the one or more candidate AIS message signals;

    decoding the one or more candidate AIS message signals in the digital input data to obtain corresponding message segments; and

    validating the decoded message segments for proper AIS formatting to produce validated decoded AIS message segments.

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