Study on Zero-Doppler Centroid Control for GEO SAR Ground Observation

Jiang, Yicheng; Hu, Bin; Zhang, Yun; Lian, Meng; Wang, Zhuoqun

doi:10.1155/2014/549269

Cited by 6 publications

(2 citation statements)

References 6 publications

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“…However, the residual Doppler central frequency can be up to kilohertz when the satellite runs at the geosynchronous orbit with a non-negligible orbital eccentricity, due to the Earth rotation and elliptical orbit [10][11][12]. Reference [13] proposed an attitude steering method combining pitch and rotation to accurately reduce the residual Doppler center error when the look angle of radar is out of an expected range. However, this approach is difficult to implement in GEO SAR.…”

Section: Introductionmentioning

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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Section: Introductionmentioning

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 two-dimensional pitch and roll steering (2D-PRS) technology for Geo-SAR broadside imaging is presented in [40]. A new 2D-PRSC method for squint staring mode is proposed in this paper.…”

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confidence: 99%

The Staring Mode Properties and Performance of Geo-SAR Satellite with Reflector Antenna

Zhao

Zhang

2022

Remote Sensing

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Geosynchronous synthetic aperture radar (Geo-SAR) with a short revisit time can obtain wide-area images. This paper advances a new two-dimensional pitch and roll squint controlling (2D-PRSC) method that can make satellites continuously stare at any scene in the whole orbital period. The maximum attitude steering angle is less than ±7.6 degrees, and the attitude controlling time can be greatly shortened compared with the yaw steering method. Furthermore, a Geo-SAR staring mode model is illustrated and compared with that of low earth orbital SAR (Leo-SAR). Finally, Geo-SAR’s ambiguity property is discussed. The simulation results illuminate that the cross-term ambiguity to signal ratio (CASR) also needs to be considered in addition to the azimuth and range ambiguity to signal ratio (AASR, RASR), and the whole orbital ergodic analysis should be carried out. To ensure that RASR, AASR, and CASR meet the requirement of −20 dB, it is necessary to select an appropriate PRF in the range of a few hundred Hertz.

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Generalized Omega-K Algorithm for Geosynchronous SAR Image Formation

Jiang

Zhang

et al. 2015

IEEE Geosci. Remote Sensing Lett.

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Study on Zero-Doppler Centroid Control for GEO SAR Ground Observation

Cited by 6 publications

References 6 publications

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

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

The Staring Mode Properties and Performance of Geo-SAR Satellite with Reflector Antenna

Generalized Omega-K Algorithm for Geosynchronous SAR Image Formation

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