Spaceborne THz-ISAR Imaging of Space Target with Joint Motion Compensation Based on FrFT and GWO

Recently, terahertz (THz) radar has been widely researched for its high-resolution in space target imaging. Due to the high rendezvous speed and the short wavelength of THz radar, the traditional stop-and-go model, along with its supporting algorithms, is not applicable. Therefore, a method that joi...

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Main Authors: Ao Zhou, Qi Yang, Zhian Yuan, Hongqiang Wang, Jun Yi, Shuangxun Li
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Remote Sensing
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Online Access:https://www.mdpi.com/2072-4292/17/13/2152
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author Ao Zhou
Qi Yang
Zhian Yuan
Hongqiang Wang
Jun Yi
Shuangxun Li
author_facet Ao Zhou
Qi Yang
Zhian Yuan
Hongqiang Wang
Jun Yi
Shuangxun Li
author_sort Ao Zhou
collection DOAJ
description Recently, terahertz (THz) radar has been widely researched for its high-resolution in space target imaging. Due to the high rendezvous speed and the short wavelength of THz radar, the traditional stop-and-go model, along with its supporting algorithms, is not applicable. Therefore, a method that jointly compensates the intra- and inter- pulse errors of space targets’ echo is proposed. The algorithm includes the following steps: firstly, a coarse estimation of targets’ translational velocity at part of pulses is conducted through Fractional Fourier transform (FrFT). Then, the improved least square fitting (ILSF) is employed to parameterize the velocity–time dependency of the target. Furthermore, the concept of synthetic waveform entropy (SWE) of a one-dimensional range profile is put forward as the accuracy metric of envelope alignment. Finally, with SWE serving as the fitness function, the Grey Wolf Optimizer (GWO) algorithm is used to search for optimal estimated translation parameters. After several iterations, a fine-grained estimation of target motion parameters is achieved, while simultaneously accomplishing precise joint compensation for intra-pulse and inter-pulse errors. The validity of the proposed method is verified by numerical simulation, electromagnetic calculation data, and field-measured data.
format Article
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institution Kabale University
issn 2072-4292
language English
publishDate 2025-06-01
publisher MDPI AG
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series Remote Sensing
spelling doaj-art-9ee8416cabaa470881f79e61d8172cff2025-08-20T03:50:20ZengMDPI AGRemote Sensing2072-42922025-06-011713215210.3390/rs17132152Spaceborne THz-ISAR Imaging of Space Target with Joint Motion Compensation Based on FrFT and GWOAo Zhou0Qi Yang1Zhian Yuan2Hongqiang Wang3Jun Yi4Shuangxun Li5College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, ChinaCollege of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, ChinaCollege of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, ChinaCollege of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, ChinaCollege of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, ChinaCollege of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, ChinaRecently, terahertz (THz) radar has been widely researched for its high-resolution in space target imaging. Due to the high rendezvous speed and the short wavelength of THz radar, the traditional stop-and-go model, along with its supporting algorithms, is not applicable. Therefore, a method that jointly compensates the intra- and inter- pulse errors of space targets’ echo is proposed. The algorithm includes the following steps: firstly, a coarse estimation of targets’ translational velocity at part of pulses is conducted through Fractional Fourier transform (FrFT). Then, the improved least square fitting (ILSF) is employed to parameterize the velocity–time dependency of the target. Furthermore, the concept of synthetic waveform entropy (SWE) of a one-dimensional range profile is put forward as the accuracy metric of envelope alignment. Finally, with SWE serving as the fitness function, the Grey Wolf Optimizer (GWO) algorithm is used to search for optimal estimated translation parameters. After several iterations, a fine-grained estimation of target motion parameters is achieved, while simultaneously accomplishing precise joint compensation for intra-pulse and inter-pulse errors. The validity of the proposed method is verified by numerical simulation, electromagnetic calculation data, and field-measured data.https://www.mdpi.com/2072-4292/17/13/2152terahertz (THz) radarinverse synthetic aperture radar (ISAR)Fractional Fourier transform (FrFT)Grey Wolf Optimizer (GWO)
spellingShingle Ao Zhou
Qi Yang
Zhian Yuan
Hongqiang Wang
Jun Yi
Shuangxun Li
Spaceborne THz-ISAR Imaging of Space Target with Joint Motion Compensation Based on FrFT and GWO
Remote Sensing
terahertz (THz) radar
inverse synthetic aperture radar (ISAR)
Fractional Fourier transform (FrFT)
Grey Wolf Optimizer (GWO)
title Spaceborne THz-ISAR Imaging of Space Target with Joint Motion Compensation Based on FrFT and GWO
title_full Spaceborne THz-ISAR Imaging of Space Target with Joint Motion Compensation Based on FrFT and GWO
title_fullStr Spaceborne THz-ISAR Imaging of Space Target with Joint Motion Compensation Based on FrFT and GWO
title_full_unstemmed Spaceborne THz-ISAR Imaging of Space Target with Joint Motion Compensation Based on FrFT and GWO
title_short Spaceborne THz-ISAR Imaging of Space Target with Joint Motion Compensation Based on FrFT and GWO
title_sort spaceborne thz isar imaging of space target with joint motion compensation based on frft and gwo
topic terahertz (THz) radar
inverse synthetic aperture radar (ISAR)
Fractional Fourier transform (FrFT)
Grey Wolf Optimizer (GWO)
url https://www.mdpi.com/2072-4292/17/13/2152
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