Adaptive clutter filter for maritime surface search radar
First Claim
1. A method, comprising:
- obtaining a time sequence of raw radar data for a region of space;
subdividing the raw radar data into a plurality of processing frames;
for a processing frame, subdividing the processing frame into a plurality of processing cells and iteratively processing the processing cells of a processing frame byselecting a single processing cell for processing;
transforming the radar data of the processing cell to form transformed radar data;
performing a Fourier transform to convert the transformed radar data from the time domain to the Fourier domain (FD) to form FD radar data;
converting the FD radar data to a FD Power Spectrum Density (FDPSD);
smoothing the FDPSD;
thresholding the FDPSD based upon a threshold parameter;
estimating the speckle clutter noise power for the processing cell;
estimating the local non-speckle clutter for the processing cell;
removing the local non-speckle clutter from the processing cell in the Fourier domain to form filtered FD radar data; and
performing an inverse Fourier transform to convert the filtered FD radar data back to the time domain.
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Accused Products
Abstract
A time sequence of raw radar data for a region of space is subdivided into a plurality of processing frames. The processing frames are subdivided into a plurality of processing cells and iteratively processed by selecting a single processing cell for processing, transforming the radar data of the processing cell to form transformed radar data in either the time domain or the Fourier domain. The transformed data is converted to a Power Spectrum Density Matrix in the case of the Fourier domain and a Time Space Correlation Matrix in the case of the time domain. This is smoothed and thresholded and then the clutter for the processing cell is estimated. Estimated local non-speckle clutter is estimated and removed from the transformed radar data, with the cleaned transformed radar data converted back to the time domain if required.
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Citations
32 Claims
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1. A method, comprising:
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obtaining a time sequence of raw radar data for a region of space; subdividing the raw radar data into a plurality of processing frames; for a processing frame, subdividing the processing frame into a plurality of processing cells and iteratively processing the processing cells of a processing frame by selecting a single processing cell for processing; transforming the radar data of the processing cell to form transformed radar data; performing a Fourier transform to convert the transformed radar data from the time domain to the Fourier domain (FD) to form FD radar data; converting the FD radar data to a FD Power Spectrum Density (FDPSD); smoothing the FDPSD; thresholding the FDPSD based upon a threshold parameter; estimating the speckle clutter noise power for the processing cell; estimating the local non-speckle clutter for the processing cell; removing the local non-speckle clutter from the processing cell in the Fourier domain to form filtered FD radar data; and performing an inverse Fourier transform to convert the filtered FD radar data back to the time domain. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus, comprising:
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means for obtaining a time sequence of raw radar data for a region of space; means for subdividing the raw radar data into a plurality of processing frames; means for subdividing the processing frame into a plurality of processing cells and iteratively processing the processing cells of a processing frame by selecting a single processing cell for processing; transforming the radar data of the processing cell to form transformed radar data; performing a Fourier transform to convert the transformed radar data from the time domain to the Fourier domain (FD) to form FD radar data; converting the FD radar data to a FD Power Spectrum Density (FDPSD); smoothing the FDPSD; thresholding the FDPSD based upon a threshold parameter; estimating the speckle clutter noise power for the processing cell; estimating the local non-speckle clutter for the processing cell; removing the local non-speckle clutter from the processing cell in the Fourier domain to form filtered FD radar data; and performing an inverse Fourier transform to convert the filtered FD radar data back to the time domain. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. An apparatus, comprising:
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an input device configured to receive a time sequence of raw radar data for a region of space; a processing device configured to subdivide the raw radar data into a plurality of processing frames; a processing device configured subdivide a processing frame into a plurality of processing cells and iteratively process the processing cells of the processing frame by selecting a single processing cell for processing; transforming the radar data of the processing cell to form transformed radar data; performing a Fourier transform to convert the transformed radar data from the time domain to the Fourier domain (FD) to form FD radar data; converting the FD radar data to a FD Power Spectrum Density (FDPSD); smoothing the FDPSD; thresholding the FDPSD based upon a threshold parameter; estimating the speckle clutter noise power for the processing cell; estimating the local non-speckle clutter for the processing cell; removing the local non-speckle clutter from the processing cell in the Fourier domain to form filtered FD radar data; and performing an inverse Fourier transform to convert the filtered FD radar data back to the time domain.
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19. A method, comprising:
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obtaining a time sequence of raw radar data for a region of space; subdividing the raw radar data into a plurality of processing frames; for a processing frame, subdividing the processing frame into a plurality of processing cells and iteratively processing the processing cells of a processing frame by selecting a single processing cell for processing; transforming the radar data of the processing cell to form transformed radar data; converting the transformed radar data to a Time Space Correlation Matrix (TSCM); smoothing the TSCM; thresholding the TSCM based upon a threshold parameter; estimating the speckle clutter noise power for the processing cell; estimating the local non-speckle clutter for the processing cell; removing the local non-speckle clutter from the processing cell to form filtered radar data. - View Dependent Claims (20, 21, 22, 23, 24)
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25. An apparatus, comprising:
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means for obtaining a time sequence of raw radar data for a region of space; means for subdividing the raw radar data into a plurality of processing frames; means for subdividing the processing frame into a plurality of processing cells and iteratively processing the processing cells of a processing frame by selecting a single processing cell for processing; transforming the radar data of the processing cell to form transformed radar data; converting the transformed radar data to a Time Space Correlation Matrix (TSCM); smoothing the TSCM; thresholding the TSCM based upon a threshold parameter; estimating the speckle clutter noise power for the processing cell; estimating the local non-speckle clutter for the processing cell; removing the local non-speckle clutter from the processing cell to form filtered radar data. - View Dependent Claims (26, 27, 28, 29, 30, 31)
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32. An apparatus, comprising:
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an input device configured to receive a time sequence of raw radar data for a region of space; a processing device configured to subdivide the raw radar data into a plurality of processing frames; subdivide a processing frame into a plurality of processing cells; and iteratively process the processing cells of the processing frame by selecting a single processing cell for processing; transforming the radar data of the processing cell to form transformed radar data; converting the transformed radar data to a Time Space Correlation Matrix (TSCM); smoothing the TSCM; thresholding the TSCM based upon a threshold parameter; estimating the speckle clutter noise power for the processing cell; estimating the local non-speckle clutter for the processing cell; and removing the local non-speckle clutter from the processing cell to form filtered radar data.
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Specification