Elevation Spatial Variation Analysis and Compensation in GEO SAR Imaging

Chang, Faguang; Li, Dexin; Dong, Zhen; Huang, Yang; He, Zhihua; Chen, Xing

doi:10.3390/rs13101888

Cited by 6 publications

(8 citation statements)

References 25 publications

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“…The conclusion is also reached that the algorithm can work well under low-SNR conditions. The results obtained in [1,2] are of great practical meaning and can be easily applied in GEO SAR wide swath terrain observation.…”

Section: Overview Of Contributionsmentioning

confidence: 95%

“…In [1,2], the authors worked with signal processing in geosynchronous synthetic aperture radar (GEO SAR) imaging. Compared with low earth orbit SAR (LEO SAR), geosynchronous synthetic aperture radar (GEO SAR) has many advantages, such as its high resolution and wide swath and being unaffected by national boundaries and meteorological conditions.…”

Section: Overview Of Contributionsmentioning

confidence: 99%

“…Despite being one of the most important sources of error in spaceborne SAR, elevation spatial variation is still not analyzed nearly enough in the literature. Therefore, the authors in [2] decided to focus on the analysis of this error. First, the decorrelation problems caused by spatial variation were presented.…”

Section: Overview Of Contributionsmentioning

confidence: 99%

“…For a GEO SAR image with a complex scene, the elevation spatial variation error can be broken down into a slow variant slope and the remaining fast variant part. While the first was analyzed in [2], the second is the focus of [1]. Authors propose a block map-drift phase gradient autofocus (block-MD-PGA) algorithm to compensate for the random phase error part.…”

Section: Overview Of Contributionsmentioning

confidence: 99%

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Radar and Sonar Imaging and Processing (2nd Edition)

2021

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The 14 papers (from 29 submitted) published in the Special Issue “Radar and Sonar Imaging Processing (2nd Edition)” highlight a variety of topics related to remote sensing with radar and sonar sensors. The sequence of articles included in the SI deal with a broad profile of aspects of the use of radar and sonar images in line with the latest scientific trends, in which the latest developments in science, including artificial intelligence, were used.

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Section: Overview Of Contributionsmentioning

confidence: 95%

Section: Overview Of Contributionsmentioning

confidence: 99%

Section: Overview Of Contributionsmentioning

confidence: 99%

Section: Overview Of Contributionsmentioning

confidence: 99%

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Radar and Sonar Imaging and Processing (2nd Edition)

2021

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“…The high order Taylor expansion slant range model is adopted in the GEO SAR systems [16,17]. Calculation of the azimuth frequency difference between the beginning and ending positions within the synthetic aperture time is the basic idea of azimuth bandwidth B a calculation, as shown in Equation ( 10) [18].…”

Section: Accurate Doppler Modelmentioning

confidence: 99%

An Accurate Doppler Parameters Calculation Method of Geosynchronous SAR Considering Real-Time Zero-Doppler Centroid Control

Chang

Yu²,

et al. 2021

Remote Sensing

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The zero-Doppler centroid control in geosynchronous synthetic aperture radar (GEO SAR) is beneficial to reduce the imaging complexity (reduces range-azimuth coupling in received data), which can be realized by adjusting the radar line of sight (RLS). In order to maintain the zero-Doppler centroid throughout the whole orbit of the GEO SAR satellite, the RLS needs to be adjusted in real-time. Due to the ultra-long synthetic aperture time of GEO SAR, the RLS variation during the synthetic aperture time cannot be neglected. However, in the previous related papers, the real-time variation of RLS during the synthetic aperture time was not taken into account in the calculation of Doppler parameters, which are closely related to the RLS, resulting in inaccurate calculation of Doppler parameters. Considering this issue, an accurate Doppler model (the model of relative motion between satellite and ground target) of GEO SAR is proposed in this paper for the accurate calculation of Doppler parameters (Doppler centroid and Doppler bandwidth and other parameters). Finally, simulation experiments are designed to confirm the effectiveness and necessity of the proposed model. The results indicate that the RLS variation during the synthetic aperture time has a considerable effect on Doppler parameters performance of the GEO SAR, and refers to a more stable azimuth resolution performance (the resolution is kept near a relatively stable value at most positions of the elliptical orbit) compared with the case that does not consider the real-time zero-Doppler centroid control.

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Sub retrograde geosynchronous orbit SAR: parameter design and performance analysis

Li,

Zhang,

Liu

et al. 2023

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

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In recent years, Geosynchronous synthetic aperture radar (GEO SAR) has attracted many scientists to carry out relevant research. Its research is in-depth and gradually maturing. However, conventional GEO SAR has the problems of great influence by the earth's rotation, complex timing design, uneven flight speed in the whole orbit, and non orthogonal range and azimuth resolution, which limits it's application. A new concept of sub retrograde geosynchronous orbit SAR is proposed in this paper. Compared with traditional GEO SAR, the satellite has the advantages of less influence by the earth's rotation, simple timing, uniform motion speed in the whole orbit, shorter revisit time, better resolution and small space-variant in azimuth and range. The radar parameters of sub retrograde GEO SAR are designed. Through the research, it is found that the system sensitivity and resolution no longer change with the orbit position, and its timing design does not need to consider the range migration variation. In addition, the imaging characteristics of sub retrograde GEOSAR are investigated. The results show that, the range model can meet the imaging requirements as long as it is expanded to the fourth order. After that, the influence of orbit perturbation error in sub retrograde GEO SAR is given for the first time. Last, two ways to solve observation blind area of sub retrograde GEO SAR are proposed, one is to change the orbit inclination, another way is to use the bistatic mode. Index Terms-sub retrograde orbit, geosynchronous synthetic aperture radar (GEO SAR), system parameter design, performance analysis. I. INTRODUCTION INCE geosynchronous orbit synthetic aperture radar (GEO SAR) was proposed, it has attracted the attention of many researchers because of its short revisit period and wide observation swath. Scientists from the United States, China, Britain, Germany, Italy and other countries have carried out research on system design and imaging algorithms. In 1978, K. Tomiyasu first proposed the concept of GEO SAR [1], with the support of National Aeronautics and Space Administration (NASA), the parameter analysis of GEO SAR Manuscript received xx; revised xx ; accepted xx. Date of publication xx; date of current version xx.

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Elevation Spatial Variation Analysis and Compensation in GEO SAR Imaging

Cited by 6 publications

References 25 publications

Radar and Sonar Imaging and Processing (2nd Edition)

Radar and Sonar Imaging and Processing (2nd Edition)

An Accurate Doppler Parameters Calculation Method of Geosynchronous SAR Considering Real-Time Zero-Doppler Centroid Control

Sub retrograde geosynchronous orbit SAR: parameter design and performance analysis

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