Synthetic-aperture radar (SAR) imaging with range-resolved reflection data
First Claim
1. A computer-implemented method for performing synthetic aperture radar (SAR) imaging with range-resolved reflection data, comprising:
- analyzing a reflected spread-spectrum signal, by a computing system;
gathering the range-resolved reflection data from the spread-spectrum signal, by the computing system; and
constructing an approximation of a two-dimensional Fourier transform of a target'"'"'s scattering function, by the computing system, whereinthe construction of the approximation is performed based on the analysis and the range-resolved reflection data.
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Accused Products
Abstract
SAR imaging may be performed with range-resolved reflection data, where a spread-spectrum signal, such as a code division multiple access (CDMA) signal, is transmitted instead of a simple frequency chirp. The reflected spread-spectrum signal may be analyzed to gather range-resolved reflection data. Range-resolved reflection data may be gathered at each angular view. This data may be used to construct a more accurate approximation of the Fourier transform of the desired image than can be done by a conventional SAR approach. The image may be reconstructed from this Fourier transform using Fourier inversion techniques similar to those used in conventional SAR approaches. The range-resolved reflection scheme generally requires somewhat more processing to recover the image as compared with conventional SAR systems, but provides a significantly more stable image with less degradation from effects that plague conventional SAR systems. This can eliminate the need for phase coherency altogether and also eliminate “phase drift,” which leads to image distortion. This may be especially well suited for high resolution imaging of relatively large targets.
14 Citations
18 Claims
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1. A computer-implemented method for performing synthetic aperture radar (SAR) imaging with range-resolved reflection data, comprising:
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analyzing a reflected spread-spectrum signal, by a computing system; gathering the range-resolved reflection data from the spread-spectrum signal, by the computing system; and constructing an approximation of a two-dimensional Fourier transform of a target'"'"'s scattering function, by the computing system, wherein the construction of the approximation is performed based on the analysis and the range-resolved reflection data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A computer-implemented method for performing synthetic aperture radar (SAR) imaging with range-resolved reflection data, comprising:
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transmitting a code division multiple access (CDMA) spread-spectrum signal, by a computing system; receiving a reflected CDMA spread-spectrum signal, by the computing system; analyzing the reflected CDMA spread-spectrum signal, by a computing system; gathering the range-resolved reflection data from the CDMA spread-spectrum signal, by the computing system; constructing an approximation of a two-dimensional Fourier transform of a target'"'"'s scattering function, by the computing system; and generating a high resolution image, by the computing system, wherein the range-resolved reflection data from the CDMA spread-spectrum signal is gathered at each angular view of a plurality of angular views, and the high resolution image has a resolution of 1.5 centimeters or less, wherein the construction of the approximation is performed based on the analysis and the range-resolved reflection data. - View Dependent Claims (15, 16)
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17. A computer-implemented method for performing synthetic aperture radar (SAR) imaging with range-resolved reflection data, comprising:
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transmitting a code division multiple access (CDMA) spread-spectrum signal, by a computing system; receiving a reflected CDMA spread-spectrum signal, by the computing system; obtaining reflections from reflectors in the reflected CDMA spread-spectrum signal at each angular view as returned signals, by the computing system; correlating the returned signals, by the computing system, with a delayed version of the transmitted CDMA spread-spectrum signal to obtain the range-resolved data at each angular view, the delayed version of the transmitted CDMA signal delayed by a delay time; and constructing an approximation of a two-dimensional Fourier transform of a target'"'"'s scattering function, by the computing system, wherein the construction of the approximation is performed based on the analysis and the range-resolved reflection data. - View Dependent Claims (18)
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Specification