Coherent auto-calibration of APE and NsRCM under fast back-projection image formation for airborne SAR imaging in highly-squint angle
Synthetic Aperture Radar (SAR) imaging with a non-zero (forward) squint angle is capable of providing a longer time for reaction than that of the broadside mode. However, due to the large squint angle, there will be severe coupling between range and azimuth samples in the echoed data, which is known...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
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2018
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| Online Access: | https://hdl.handle.net/10356/86580 http://hdl.handle.net/10220/45328 |
| _version_ | 1811696331903729664 |
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| author | Yang, Lei Zhou, Song Zhao, Lifan Xing, Mengdao |
| author2 | School of Electrical and Electronic Engineering |
| author_facet | School of Electrical and Electronic Engineering Yang, Lei Zhou, Song Zhao, Lifan Xing, Mengdao |
| author_sort | Yang, Lei |
| collection | NTU |
| description | Synthetic Aperture Radar (SAR) imaging with a non-zero (forward) squint angle is capable of providing a longer time for reaction than that of the broadside mode. However, due to the large squint angle, there will be severe coupling between range and azimuth samples in the echoed data, which is known as the problematic Range Cell Migration (RCM) in the SAR community. Especially when the SAR sensor mounted on an airborne platform encounters unexpected motion deviations/errors, the coupling becomes more complicated, and it is difficult to differentiate the systematic RCM for the SAR Image Formation Processing (IFP) and the non-systematic RCM error to be compensated. To this end, a novel and accurate SAR imaging algorithm is proposed in this paper to facilitate the processing of airborne SAR data collected at a high-squint angle. Firstly, the proposed algorithm is established under a Fast Time-Domain Back-Projection (FTDBP) framework for the SAR IFP. FTDBP paves the way to avoid the complicated processing for the systematic RCM as for the conventional SAR IFP in the Doppler processing manner. It is capable of generating a high-resolution SAR image efficiently under more general geometries and configurations. Secondly, regarding the non-systematic RCM errors, the proposed algorithm realizes the compensation by correcting both the Non-systematic Range Cell Migration (NsRCM), as well as Azimuthal Phase Error (APE) in a coherent manner. It is consequently capable of auto-calibrating the effects of the motion error completely without being dependent on the airborne navigation unit. Finally, both simulated and raw data collected by the airborne squinted SAR are applied to evaluate the proposed algorithm. Comparisons with conventional algorithms are carried out to reveal the superiority of the proposed algorithm. |
| first_indexed | 2024-10-01T07:37:40Z |
| format | Journal Article |
| id | ntu-10356/86580 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T07:37:40Z |
| publishDate | 2018 |
| record_format | dspace |
| spelling | ntu-10356/865802020-03-07T13:57:29Z Coherent auto-calibration of APE and NsRCM under fast back-projection image formation for airborne SAR imaging in highly-squint angle Yang, Lei Zhou, Song Zhao, Lifan Xing, Mengdao School of Electrical and Electronic Engineering Auto-calibration Squint Synthetic Aperture Radar (SAR) Synthetic Aperture Radar (SAR) imaging with a non-zero (forward) squint angle is capable of providing a longer time for reaction than that of the broadside mode. However, due to the large squint angle, there will be severe coupling between range and azimuth samples in the echoed data, which is known as the problematic Range Cell Migration (RCM) in the SAR community. Especially when the SAR sensor mounted on an airborne platform encounters unexpected motion deviations/errors, the coupling becomes more complicated, and it is difficult to differentiate the systematic RCM for the SAR Image Formation Processing (IFP) and the non-systematic RCM error to be compensated. To this end, a novel and accurate SAR imaging algorithm is proposed in this paper to facilitate the processing of airborne SAR data collected at a high-squint angle. Firstly, the proposed algorithm is established under a Fast Time-Domain Back-Projection (FTDBP) framework for the SAR IFP. FTDBP paves the way to avoid the complicated processing for the systematic RCM as for the conventional SAR IFP in the Doppler processing manner. It is capable of generating a high-resolution SAR image efficiently under more general geometries and configurations. Secondly, regarding the non-systematic RCM errors, the proposed algorithm realizes the compensation by correcting both the Non-systematic Range Cell Migration (NsRCM), as well as Azimuthal Phase Error (APE) in a coherent manner. It is consequently capable of auto-calibrating the effects of the motion error completely without being dependent on the airborne navigation unit. Finally, both simulated and raw data collected by the airborne squinted SAR are applied to evaluate the proposed algorithm. Comparisons with conventional algorithms are carried out to reveal the superiority of the proposed algorithm. Published version 2018-07-27T07:56:49Z 2019-12-06T16:25:10Z 2018-07-27T07:56:49Z 2019-12-06T16:25:10Z 2018 Journal Article Yang, L., Zhou, S., Zhao, L., & Xing, M. (2018). Coherent auto-calibration of APE and NsRCM under fast back-projection image formation for airborne SAR imaging in highly-squint angle. Remote Sensing, 10(2), 321-. 2072-4292 https://hdl.handle.net/10356/86580 http://hdl.handle.net/10220/45328 10.3390/rs10020321 en Remote Sensing © 2018 The Author(s). Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). 21 p. application/pdf |
| spellingShingle | Auto-calibration Squint Synthetic Aperture Radar (SAR) Yang, Lei Zhou, Song Zhao, Lifan Xing, Mengdao Coherent auto-calibration of APE and NsRCM under fast back-projection image formation for airborne SAR imaging in highly-squint angle |
| title | Coherent auto-calibration of APE and NsRCM under fast back-projection image formation for airborne SAR imaging in highly-squint angle |
| title_full | Coherent auto-calibration of APE and NsRCM under fast back-projection image formation for airborne SAR imaging in highly-squint angle |
| title_fullStr | Coherent auto-calibration of APE and NsRCM under fast back-projection image formation for airborne SAR imaging in highly-squint angle |
| title_full_unstemmed | Coherent auto-calibration of APE and NsRCM under fast back-projection image formation for airborne SAR imaging in highly-squint angle |
| title_short | Coherent auto-calibration of APE and NsRCM under fast back-projection image formation for airborne SAR imaging in highly-squint angle |
| title_sort | coherent auto calibration of ape and nsrcm under fast back projection image formation for airborne sar imaging in highly squint angle |
| topic | Auto-calibration Squint Synthetic Aperture Radar (SAR) |
| url | https://hdl.handle.net/10356/86580 http://hdl.handle.net/10220/45328 |
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