Methods for two-dimensional autofocus in high resolution radar systems
First Claim
1. A two-dimensional polar geometry model method used in a synthetic aperture radar (SAR) system for removing a two-dimensional phase error in a complex image, the method comprising:
- creating the complex image with a sensor;
modeling the two-dimensional phase error as a combination of a range error which is substantially identical from pulse to pulse and a slow-time error;
fitting an unconstrained two-dimensional estimate to the modeled two-dimensional phase error; and
correcting the two-dimensional phase error to generate a corrected image.
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Abstract
Provided are two-dimensional autofocus methods in a synthetic aperture radar (SAR) system which include: (1) two-dimensional pulse pair product algorithm including shear PGA, eigenvector phase history (“EPH”), shear PGA/EPH); (2) two-dimensional optimization algorithms including parametric one-dimensional estimate/two-dimensional correction, parametric two dimensional estimate/two-dimensional correction, unconstrained two-dimensional nonparametric and constrained two-dimensional nonparametric methods; (3) a two-dimensional geometry filter algorithm; (4) a two-dimensional prominent point processing algorithm; (5) a one-dimensional phase estimate of higher order two dimensional phase errors; and, (6) a fast SHARP parametric autofocus algorithm.
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Citations
10 Claims
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1. A two-dimensional polar geometry model method used in a synthetic aperture radar (SAR) system for removing a two-dimensional phase error in a complex image, the method comprising:
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creating the complex image with a sensor; modeling the two-dimensional phase error as a combination of a range error which is substantially identical from pulse to pulse and a slow-time error; fitting an unconstrained two-dimensional estimate to the modeled two-dimensional phase error; and correcting the two-dimensional phase error to generate a corrected image. - View Dependent Claims (2, 3, 4, 5)
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6. A computer-readable medium having computer-executable instructions for a two-dimensional polar geometry filter method used in a synthetic aperture radar (SAR) system for removing a two-dimensional phase error in a complex image, the computer-executable instructions configured to perform a method comprising:
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creating the complex image with a sensor; modeling the two-dimensional phase error as a combination of a range error which is substantially identical from pulse to pulse and a slow-time error; fitting an unconstrained two-dimensional estimate to the modeled two-dimensional phase error; and correcting the two-dimensional phase error to generate a corrected image. - View Dependent Claims (7, 8, 9, 10)
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Specification