SYSTEM AND METHOD FOR DECODING AUTOMATIC IDENTIFICATION SYSTEM SIGNALS
First Claim
1. A method for detecting and decoding Automatic Identification System (AIS) signals, the method comprising:
- receiving a plurality of AIS signals at a satellite in space and pre-processing the plurality of AIS signals to produce digital input data;
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 and identifying one or more candidate AIS message signals based on the correlation signals;
determining Doppler offset estimates and time estimates for the one or more candidate AIS message signals;
decoding the one or more candidate AIS message signals to obtain corresponding message segments; and
validating decoded message segments for proper AIS formatting.
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Abstract
Various embodiments are described herein for a system and method of detecting Automatic Identification System (AIS) signals in space and decoding these signals. In one aspect, a system for performing this function is described which includes a receiver configured to receive the plurality of AIS signals and pre-process the plurality of AIS signals to produce digital input data, and a processing unit configured to process the digital input data to identify one or more candidate AIS message signals based on Doppler offsets associated with the digital input data, determine corresponding Doppler offset estimates and time estimates of the one or more candidate AIS message signals, decode the one or more candidate AIS message signals to obtain corresponding message segments and validate the decoded message segments for proper AIS formatting.
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Citations
33 Claims
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1. A method for detecting and decoding Automatic Identification System (AIS) signals, the method comprising:
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receiving a plurality of AIS signals at a satellite in space and pre-processing the plurality of AIS signals to produce digital input data; 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 and identifying one or more candidate AIS message signals based on the correlation signals; determining Doppler offset estimates and time estimates for the one or more candidate AIS message signals; decoding the one or more candidate AIS message signals to obtain corresponding message segments; and validating decoded message segments for proper AIS formatting. - View Dependent Claims (2, 3, 5, 6, 8, 9, 11, 12, 13, 14, 16)
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4. (canceled)
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7. (canceled)
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10. (canceled)
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15. (canceled)
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17. A system for detecting and decoding Automatic Identification System (AIS) signals, the system comprising:
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a receiver configured to receive the plurality of AIS signals in space and pre-process the plurality of AIS signals to produce digital input data, the receiver being located on a satellite; a processing module configured to process 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, identify one or more candidate AIS message signals based on the correlation signals, and determine a corresponding Doppler offset estimates and time estimates for the one or more candidate AIS message signals; a decoder configured to decode the one or more candidate AIS message signals to obtain corresponding message segments; and a validation module configured to validate the decoded message segments for proper AIS formatting. - View Dependent Claims (18, 19, 22, 23, 24, 25, 27, 28, 29, 30, 32)
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20. (canceled)
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21. (canceled)
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26. (canceled)
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31. (canceled)
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33. A system for detecting and decoding Automatic Identification System (AIS) signals, the system comprising:
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a receiver configured to receive the plurality of AIS signals and pre-process the plurality of AIS signals to produce digital input data; and a processing unit configured to process the digital input data to identify one or more candidate AIS message signals based on Doppler offsets associated with the digital input data, determine corresponding Doppler offset estimates and time estimates of the one or more candidate AIS message signals;
decode the one or more candidate AIS message signals to obtain corresponding message segments; and
validate the decoded message segments for proper AIS formatting.
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Specification