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...

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Autores principales:	Wei Xu, Ruibo Li, Chonghua Fang, Pingping Huang, Weixian Tan, Yaolong Qi
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	azimuth multichannel reconstruction nonuniform sampling advanced hyperbolic range equation (AHRE) synthetic aperture radar (SAR) Science Q
Acceso en línea:	https://doaj.org/article/c8859315ee5549aeb1a658160d2883c3
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spelling	oai:doaj.org-article:c8859315ee5549aeb1a658160d2883c32021-11-25T18:55:36ZAzimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation10.3390/rs132247052072-4292https://doaj.org/article/c8859315ee5549aeb1a658160d2883c32021-11-01T00:00:00Zhttps://www.mdpi.com/2072-4292/13/22/4705https://doaj.org/toc/2072-4292To 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.Wei XuRuibo LiChonghua FangPingping HuangWeixian TanYaolong QiMDPI AGarticleazimuth multichannel reconstructionnonuniform samplingadvanced hyperbolic range equation (AHRE)synthetic aperture radar (SAR)ScienceQENRemote Sensing, Vol 13, Iss 4705, p 4705 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	azimuth multichannel reconstruction nonuniform sampling advanced hyperbolic range equation (AHRE) synthetic aperture radar (SAR) Science Q
spellingShingle	azimuth multichannel reconstruction nonuniform sampling advanced hyperbolic range equation (AHRE) synthetic aperture radar (SAR) Science Q Wei Xu Ruibo Li Chonghua Fang Pingping Huang Weixian Tan Yaolong Qi Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation
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.
format	article
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
title	Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation
title_short	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_sort	azimuth multichannel reconstruction based on advanced hyperbolic range equation
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/c8859315ee5549aeb1a658160d2883c3
work_keys_str_mv	AT weixu azimuthmultichannelreconstructionbasedonadvancedhyperbolicrangeequation AT ruiboli azimuthmultichannelreconstructionbasedonadvancedhyperbolicrangeequation AT chonghuafang azimuthmultichannelreconstructionbasedonadvancedhyperbolicrangeequation AT pingpinghuang azimuthmultichannelreconstructionbasedonadvancedhyperbolicrangeequation AT weixiantan azimuthmultichannelreconstructionbasedonadvancedhyperbolicrangeequation AT yaolongqi azimuthmultichannelreconstructionbasedonadvancedhyperbolicrangeequation
_version_	1718410552789696512

Azimuth Multichannel Reconstruction Based on Advanced Hyperbolic Range Equation

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