Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation
To acquire high-resolution wide-swath (HRWS) imaging capacity, the displaced phase center multichannel azimuth beam (DPCMAB) technology is usually adopted in spaceborne synthetic aperture radar (SAR), while multichannel reconstruction must be carried out before imaging process due to azimuth nonunif...
| Main Authors: | , , , , , |
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| Format: | Article |
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MDPI AG
2021-11-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/13/22/4705 |
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| author | Wei Xu Ruibo Li Chonghua Fang Pingping Huang Weixian Tan Yaolong Qi |
| author_facet | Wei Xu Ruibo Li Chonghua Fang Pingping Huang Weixian Tan Yaolong Qi |
| author_sort | Wei Xu |
| collection | DOAJ |
| description | To acquire high-resolution wide-swath (HRWS) imaging capacity, the displaced phase center multichannel azimuth beam (DPCMAB) technology is usually adopted in spaceborne synthetic aperture radar (SAR), while multichannel reconstruction must be carried out before imaging process due to azimuth nonuniform sampling. Up to now, almost all azimuth multichannel reconstruction algorithms have been mainly based on conventional hyperbolic range equation (CHRE), but the accuracy of the CHRE model is usually not suitable for the HRWS mode, especially for high resolution and large squint observation cases. In this study, the azimuth multichannel signal model based on the advanced hyperbolic range equation (AHRE) is established and analyzed. The major difference between multichannel signal models based on CHRE and AHRE is the additional time-varying phase error between azimuth channels. The time-varying phase error is small and can be ignored in the monostatic DPCMAB SAR system, but it must be considered and compensated in the distributed DPCMAB SAR system. In addition to the time-varying phase error, additional Doppler spectrum shift and extended Doppler bandwidth should be considered in the squint case during azimuth multichannel reconstruction. The azimuth multichannel reconstruction algorithm based on AHRE is proposed in this paper. Before multichannel reconstruction and combination, time-varying phase errors between azimuth channels were first compensated, and the range-frequency-dependent de-skewing function was derived to remove the two-dimension (2D) spectrum tilt to avoid azimuth under-sampling. Then, azimuth multichannel data were reconstructed according to the azimuth multichannel impulse response based on AHRE. Finally, the range-frequency dependent re-skewing function was introduced to recover the tilted 2D spectrum. Simulation results on both point and distributed targets validated the proposed azimuth multichannel reconstruction approach. |
| first_indexed | 2024-03-10T05:05:23Z |
| format | Article |
| id | doaj.art-c8859315ee5549aeb1a658160d2883c3 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T05:05:23Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-c8859315ee5549aeb1a658160d2883c32023-11-23T01:21:58ZengMDPI AGRemote Sensing2072-42922021-11-011322470510.3390/rs13224705Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range EquationWei Xu0Ruibo Li1Chonghua Fang2Pingping Huang3Weixian Tan4Yaolong Qi5College of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, ChinaCollege of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, ChinaScience and Technology on Electromagnetic Compatibility Laboratory, China Ship Development and Design Center, Wuhan 430064, ChinaCollege of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, ChinaCollege of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, ChinaCollege of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, ChinaTo acquire high-resolution wide-swath (HRWS) imaging capacity, the displaced phase center multichannel azimuth beam (DPCMAB) technology is usually adopted in spaceborne synthetic aperture radar (SAR), while multichannel reconstruction must be carried out before imaging process due to azimuth nonuniform sampling. Up to now, almost all azimuth multichannel reconstruction algorithms have been mainly based on conventional hyperbolic range equation (CHRE), but the accuracy of the CHRE model is usually not suitable for the HRWS mode, especially for high resolution and large squint observation cases. In this study, the azimuth multichannel signal model based on the advanced hyperbolic range equation (AHRE) is established and analyzed. The major difference between multichannel signal models based on CHRE and AHRE is the additional time-varying phase error between azimuth channels. The time-varying phase error is small and can be ignored in the monostatic DPCMAB SAR system, but it must be considered and compensated in the distributed DPCMAB SAR system. In addition to the time-varying phase error, additional Doppler spectrum shift and extended Doppler bandwidth should be considered in the squint case during azimuth multichannel reconstruction. The azimuth multichannel reconstruction algorithm based on AHRE is proposed in this paper. Before multichannel reconstruction and combination, time-varying phase errors between azimuth channels were first compensated, and the range-frequency-dependent de-skewing function was derived to remove the two-dimension (2D) spectrum tilt to avoid azimuth under-sampling. Then, azimuth multichannel data were reconstructed according to the azimuth multichannel impulse response based on AHRE. Finally, the range-frequency dependent re-skewing function was introduced to recover the tilted 2D spectrum. Simulation results on both point and distributed targets validated the proposed azimuth multichannel reconstruction approach.https://www.mdpi.com/2072-4292/13/22/4705azimuth multichannel reconstructionnonuniform samplingadvanced hyperbolic range equation (AHRE)synthetic aperture radar (SAR) |
| spellingShingle | Wei Xu Ruibo Li Chonghua Fang Pingping Huang Weixian Tan Yaolong Qi Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation Remote Sensing azimuth multichannel reconstruction nonuniform sampling advanced hyperbolic range equation (AHRE) synthetic aperture radar (SAR) |
| title | Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation |
| title_full | Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation |
| title_fullStr | Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation |
| title_full_unstemmed | Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation |
| title_short | Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation |
| title_sort | azimuth multichannel reconstruction based on advanced hyperbolic range equation |
| topic | azimuth multichannel reconstruction nonuniform sampling advanced hyperbolic range equation (AHRE) synthetic aperture radar (SAR) |
| url | https://www.mdpi.com/2072-4292/13/22/4705 |
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