An Imaging Algorithm for Spaceborne High-Squint <i>L</i>-Band SAR Based on Time-Domain Rotation

Sun, Liwei; Yu, Ze; Li, Chunsheng; Liu, Wei; Wang, Shusen; Geng, Jiwen

doi:10.1109/jstars.2019.2953836

Cited by 5 publications

(2 citation statements)

References 26 publications

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“…To quickly and efficiently complete some urgent observation tasks, the spaceborne SAR is required to carry out the high-resolution and real-time observation for specific areas, so the high-resolution real-time imaging processing for the spotlight imaging mode is developed in the spaceborne SAR technology [13][14][15][16]. However, in the case of high-resolution real-time imaging of the spaceborne spotlight SAR, the long synthetic aperture time makes the trajectory of the spaceborne SAR more complicated and the data volume of the echo signal increase sharply [17,18], which bring great challenges to the high-resolution real-time imaging. As we know large data take a long time to transmit, so it is not appropriate to directly transmit the echo data in the high-resolution real-time spaceborne SAR imaging.…”

Section: Introductionmentioning

confidence: 99%

High-Resolution Real-Time Imaging Processing for Spaceborne Spotlight SAR With Curved Orbit via Subaperture Coherent Superposition in Image Domain

Liu

Sun

Guo

et al. 2022

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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With the increasing of application requirements, the high-resolution real-time imaging processing of the spaceborne spotlight synthetic aperture radar (SAR) has been developed. Since the traditional real-time imaging algorithms have the problems that the range model has errors and the two-dimensional space-variance of the equivalent velocity caused by the curved orbit cannot be effectively eliminated. Thus this paper proposes a high-resolution real-time imaging algorithm for spaceborne spotlight SAR with curved orbit via sub-aperture coherent superposition in image domain. In this paper, the echo data are first divided into sub-apertures to avoid the azimuth spectrum aliasing. After that, the two-dimensional space-variance of the equivalent velocity caused by the curved orbit can be eliminated by the method of azimuth time scale transformation, higher-order phase compensation and introducing phase transition function. Then, the dechirp function is applied for the sub-aperture signals to obtain the partial-resolution sub-aperture images. Finally, these partial-resolution sub-aperture images are coherently superposed in the image domain to obtain the final full-resolution image of the whole echo data. Moreover, the proposed algorithm improves the real-time performance by adopting the idea that the sub-aperture data recording and sub-aperture real-time imaging processing are synchronized, which greatly accelerates the acquisition of the final full-resolution imaging result. At the end of this paper, the simulations and the real-time performance analysis are performed to validate the proposed algorithm.Index Terms-spaceborne synthetic aperture radar (SAR), spotlight mode, high-resolution real-time imaging, curved orbit, sub-aperture coherent superposition.

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Section: Introductionmentioning

confidence: 99%

High-Resolution Real-Time Imaging Processing for Spaceborne Spotlight SAR With Curved Orbit via Subaperture Coherent Superposition in Image Domain

Liu

Sun

Guo

et al. 2022

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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“…And then, Sun et al constructed an improved ω − K algorithm for spatial high-magnification L-band SAR imaging [14]. Meanwhile, Fan et al presented a modified range-Doppler algorithm (M-RDA) for handling high squint SAR, which modifies the migration of ranging units in the ranging frequency domain and avoids interpolation operation [15]. However, the above studies discussed the problem of squint imaging with full-sampled echo, how to achieve high-quality imaging from full-even down-sampled squint echo data still requires future research.…”

Section: Introductionmentioning

confidence: 99%

Frequency-Scaling-Based Spaceborne Squint SAR Sparse Imaging

Song

Zhang

Jin

et al. 2022

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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In synthetic aperture radar (SAR), due to the characteristics of squint data in spaceborne imaging geometry, a more accurate range cell migration correction (RCMC) operation is necessary. Furthermore, imaging degradation due to ignoring range-variant filtering needed for secondary range compression (SRC) limits SAR imaging. In addition, due to enormous computational complexity required for squint SAR data processing, the existing imaging methods, for instance, chirp scaling algorithm (CSA) and range-Doppler algorithm (RDA) are no longer sufficient, especially for large-scale scenes. In order to solve above problems, this paper presents a novel spaceborne squint SAR sparse imaging method, which could not only eliminate the effects of squint to a certain extent, but also improve the performance of focused SAR image. Compared with matched filtering (MF) based squint imaging algorithm, the proposed method can obtain the SAR images with higher quality from full-or down-sampled echo data.

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Ultra-High-Resolution Spaceborne and Squint SAR Imaging for Height-Variant Geometry Using Polynomial Range Model

Kang

Lee

2023

IEEE Trans. Aerosp. Electron. Syst.

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An Imaging Algorithm for Spaceborne High-Squint L-Band SAR Based on Time-Domain Rotation

Abstract: This is a repository copy of An imaging algorithm for spaceborne high-squint L-band SAR based on time-domain rotation.

Cited by 5 publications

References 26 publications

High-Resolution Real-Time Imaging Processing for Spaceborne Spotlight SAR With Curved Orbit via Subaperture Coherent Superposition in Image Domain

High-Resolution Real-Time Imaging Processing for Spaceborne Spotlight SAR With Curved Orbit via Subaperture Coherent Superposition in Image Domain

Frequency-Scaling-Based Spaceborne Squint SAR Sparse Imaging

Ultra-High-Resolution Spaceborne and Squint SAR Imaging for Height-Variant Geometry Using Polynomial Range Model

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