A Novel Imaging Algorithm for High-Resolution Wide-Swath Space-Borne SAR Based on a Spatial-Variant Equivalent Squint Range Model
High-Resolution Wide-Swath (HRWS) is an important development direction of space-borne Synthetic Aperture Radar (SAR). The two-dimensional spatial variation of the Doppler parameters is the most significant characteristic of the sliding spotlight space-borne SAR system under the requirements of HRWS...
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| Format: | Article |
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MDPI AG
2022-01-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/14/2/368 |
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| author | Yanan Guo Pengbo Wang Jie Chen Zhirong Men Lei Cui Lei Zhuang |
| author_facet | Yanan Guo Pengbo Wang Jie Chen Zhirong Men Lei Cui Lei Zhuang |
| author_sort | Yanan Guo |
| collection | DOAJ |
| description | High-Resolution Wide-Swath (HRWS) is an important development direction of space-borne Synthetic Aperture Radar (SAR). The two-dimensional spatial variation of the Doppler parameters is the most significant characteristic of the sliding spotlight space-borne SAR system under the requirements of HRWS. Therefore, the compensation of the two-dimensional spatial variation is the most challenging problem faced in the imaging of HRWS situations. The compensatory approach is then proposed to address this problem in this paper. The spatial distribution of the Doppler parameters for the HRWS space-borne SAR data in the sliding spotlight working mode is firstly analyzed, based on which a Spatial-Variant Equivalent Slant Range Model (SV-ESRM) is put forward to accurately formulate the range history for the distributed target. By introducing an azimuth-varying term, the SV-ESRM can precisely describe the range history for not only central targets but also marginal targets, which is more adaptive to the HRWS space-borne SAR requirements. Based on the SV-ESRM, a Modified Hybrid Correlation Algorithm (MHCA) for HRWS space-borne SAR imaging is derived to focus the full-scene data on one single imaging processing. A Doppler phase perturbation incorporated with the sub-aperture method is firstly performed to eliminate the azimuth variation of the Doppler parameters and remove the Doppler spectrum aliasing. Then, an advanced hybrid correlation is employed to achieve the precise differential Range Cell Migration (RCM) correction and Doppler phase compensation. A range phase perturbation method is also utilized to eliminate the range profile defocusing caused by range-azimuth coupling for marginal targets. Finally, a de-rotation processing is performed to remove the azimuth aliasing and the residual azimuth-variance and obtain the precisely focused SAR image. Simulation shows that the SAR echoes for a 20 km × 20 km scene with a 0.25 m resolution in both the range and azimuth directions could be focused precisely via one single imaging processing, which validates the feasibility of the proposed algorithm. |
| first_indexed | 2024-03-10T00:36:19Z |
| format | Article |
| id | doaj.art-5af283bd6577448f8b3eeedee54d5a5f |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T00:36:19Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-5af283bd6577448f8b3eeedee54d5a5f2023-11-23T15:16:34ZengMDPI AGRemote Sensing2072-42922022-01-0114236810.3390/rs14020368A Novel Imaging Algorithm for High-Resolution Wide-Swath Space-Borne SAR Based on a Spatial-Variant Equivalent Squint Range ModelYanan Guo0Pengbo Wang1Jie Chen2Zhirong Men3Lei Cui4Lei Zhuang5School of Electronics and Information Engineering, Beihang University, Beijing 100191, ChinaSchool of Electronics and Information Engineering, Beihang University, Beijing 100191, ChinaSchool of Electronics and Information Engineering, Beihang University, Beijing 100191, ChinaSchool of Electronics and Information Engineering, Beihang University, Beijing 100191, ChinaShanghai Institute of Satellite Engineering, Shanghai 201100, ChinaShanghai Institute of Satellite Engineering, Shanghai 201100, ChinaHigh-Resolution Wide-Swath (HRWS) is an important development direction of space-borne Synthetic Aperture Radar (SAR). The two-dimensional spatial variation of the Doppler parameters is the most significant characteristic of the sliding spotlight space-borne SAR system under the requirements of HRWS. Therefore, the compensation of the two-dimensional spatial variation is the most challenging problem faced in the imaging of HRWS situations. The compensatory approach is then proposed to address this problem in this paper. The spatial distribution of the Doppler parameters for the HRWS space-borne SAR data in the sliding spotlight working mode is firstly analyzed, based on which a Spatial-Variant Equivalent Slant Range Model (SV-ESRM) is put forward to accurately formulate the range history for the distributed target. By introducing an azimuth-varying term, the SV-ESRM can precisely describe the range history for not only central targets but also marginal targets, which is more adaptive to the HRWS space-borne SAR requirements. Based on the SV-ESRM, a Modified Hybrid Correlation Algorithm (MHCA) for HRWS space-borne SAR imaging is derived to focus the full-scene data on one single imaging processing. A Doppler phase perturbation incorporated with the sub-aperture method is firstly performed to eliminate the azimuth variation of the Doppler parameters and remove the Doppler spectrum aliasing. Then, an advanced hybrid correlation is employed to achieve the precise differential Range Cell Migration (RCM) correction and Doppler phase compensation. A range phase perturbation method is also utilized to eliminate the range profile defocusing caused by range-azimuth coupling for marginal targets. Finally, a de-rotation processing is performed to remove the azimuth aliasing and the residual azimuth-variance and obtain the precisely focused SAR image. Simulation shows that the SAR echoes for a 20 km × 20 km scene with a 0.25 m resolution in both the range and azimuth directions could be focused precisely via one single imaging processing, which validates the feasibility of the proposed algorithm.https://www.mdpi.com/2072-4292/14/2/368synthetic aperture radar (SAR)high-resolution wide-swath (HRWS)Spatial-Variant Equivalent Slant Range Model (SV-ESRM)imaging algorithmDoppler phase perturbation |
| spellingShingle | Yanan Guo Pengbo Wang Jie Chen Zhirong Men Lei Cui Lei Zhuang A Novel Imaging Algorithm for High-Resolution Wide-Swath Space-Borne SAR Based on a Spatial-Variant Equivalent Squint Range Model Remote Sensing synthetic aperture radar (SAR) high-resolution wide-swath (HRWS) Spatial-Variant Equivalent Slant Range Model (SV-ESRM) imaging algorithm Doppler phase perturbation |
| title | A Novel Imaging Algorithm for High-Resolution Wide-Swath Space-Borne SAR Based on a Spatial-Variant Equivalent Squint Range Model |
| title_full | A Novel Imaging Algorithm for High-Resolution Wide-Swath Space-Borne SAR Based on a Spatial-Variant Equivalent Squint Range Model |
| title_fullStr | A Novel Imaging Algorithm for High-Resolution Wide-Swath Space-Borne SAR Based on a Spatial-Variant Equivalent Squint Range Model |
| title_full_unstemmed | A Novel Imaging Algorithm for High-Resolution Wide-Swath Space-Borne SAR Based on a Spatial-Variant Equivalent Squint Range Model |
| title_short | A Novel Imaging Algorithm for High-Resolution Wide-Swath Space-Borne SAR Based on a Spatial-Variant Equivalent Squint Range Model |
| title_sort | novel imaging algorithm for high resolution wide swath space borne sar based on a spatial variant equivalent squint range model |
| topic | synthetic aperture radar (SAR) high-resolution wide-swath (HRWS) Spatial-Variant Equivalent Slant Range Model (SV-ESRM) imaging algorithm Doppler phase perturbation |
| url | https://www.mdpi.com/2072-4292/14/2/368 |
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