2-D Wavenumber Domain Autofocusing for High-Resolution Highly Squinted SAR Imaging Based on Equivalent Broadside Model

The wavenumber domain algorithm is an ideal solution for high-resolution and highly squinted (HRHS) synthetic aperture radar (SAR) imaging in the case of an ideal straight trajectory. However, for airborne HRHS SAR imaging, the Stolt mapping leads to nonsystematic range cell migration (NsRCM) and se...

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Bibliographic Details
Published in:IEEE transactions on geoscience and remote sensing 2023, Vol.61, p.1-15
Main Authors: Deng, Yuhui, Sun, Guang-Cai, Han, Liang, Wang, Yuqi, Zhang, Yu, Xing, Mengdao
Format: Article
Language:English
Subjects:
2-D wavenumber domain autofocusing
Algorithms
Azimuth
azimuth resampling
Cell migration
Compression
Data acquisition
Equivalence
equivalent broadside model
Error correction
extended range migration algorithm (ERMA)
High resolution
high-resolution and highly squinted (HRHS) synthetic aperture radar (SAR)
Image compression
Image resolution
Imagery
Imaging
Imaging techniques
Motion compensation
Phase error
Radar
Radar imaging
Radar polarimetry
Resampling
SAR (radar)
Signal processing algorithms
Synthetic aperture radar
Trajectory
Wavelengths
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Summary:The wavenumber domain algorithm is an ideal solution for high-resolution and highly squinted (HRHS) synthetic aperture radar (SAR) imaging in the case of an ideal straight trajectory. However, for airborne HRHS SAR imaging, the Stolt mapping leads to nonsystematic range cell migration (NsRCM) and secondary range compression (SRC) for the HRHS SAR, which causes the HRHS SAR image to defocus severely. To obtain a well-focused HRHS SAR image, a new autofocusing algorithm for HRHS SAR imagery based on an equivalent broadside model is proposed in this article. After coarse motion compensation, linear range walk correction and azimuth resampling are employed to transform the HRHS SAR data into the equivalent broadside SAR data, which has been proved to greatly reduce NsRCM and SRC. After that, the motion error prior structure in the 2-D wavenumber domain is revealed. According to the structure, a novel 2-D wavenumber domain autofocusing algorithm is proposed by the relationship between the 1-D azimuth phase error and the 2-D wavenumber domain phase error correction. Finally, the well-focused HRHS SAR imagery is obtained. Experiments based on simulated and acquired data are carried out to verify the necessity and effectiveness of the proposed algorithm for HRHS SAR imaging.
ISSN:0196-2892
1558-0644
DOI:10.1109/TGRS.2023.3328392