The Influence of the Azimuth RCS Pattern of Calibrator on SAR Absolute Calibration

Du, Shaoyan; Hong, Jin; Wang, Yu; Xing, Kaichu; Qiu, Tian; Huang, Jianjun

doi:10.1109/lgrs.2021.3120433

Cited by 4 publications

(2 citation statements)

References 13 publications

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“…Second, to extract permanent scatterers, long-time interferometric SAR data are needed, and the interferometric processing is very complex. In addition, the side lobes of point targets can also lead to radiometric errors and require additional corrections [15], [41], [42].…”

Section: B Radiometric Calibration Based On Natural Point Targetsmentioning

confidence: 99%

“…They are difficult to share with other SAR sensors that operate at drastically different incidence angles or operating frequencies. With the launch of more SAR satellites and constellation satellites, the implementation of this approach becomes unfeasible due to the difficulties in increasing the number of artificial calibrators, thus emphasizing the need for alternative SAR calibration methods [15].…”

Section: Introductionmentioning

confidence: 99%

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Synthetic Aperture Radar Radiometric Cross Calibration Based on Distributed Targets

Zhou

Duan

et al. 2022

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

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SAR radiometric calibration is an essential step in inferring meaningful physical information about the target. The majority of current calibration processes are directly based on artificial calibrators, but the number of calibrators is always restricted. Cross calibration, which has been widely used for optical and meteorological satellites, performs calibration by another calibrated satellite. Distributed targets are used as the calibration reference, allowing for frequent calibration. However, the potential of introducing cross calibration to SAR satellites has not been confirmed, and two issues must be resolved: 1) The number of calibration targets available for cross calibration is limited to a few known distributed targets; 2) The imaging parameters of calibrated and uncalibrated SARs are different, which may cause errors when cross calibration is applied. In this paper, a method for selecting stable distributed targets using time-series stability analysis was presented firstly. The salinealkali land and urban areas were selected as the calibration targets with low and high backscattering, respectively. Second, different stable pixel extraction methods were adopt based on the characteristics of different targets. Thirdly, the Oh model was used to correct the scattering difference caused by the incidence angle difference, which greatly improved the accuracy of the backscattering coefficients of the calibration targets. The cross calibration experiments on the same series of satellite (Sentinel-1A/B) data revealed that the accuracy of cross calibration was comparable to the accuracy of the artificial calibrator-based method, with a difference of less than 0.48 dB (1σ).

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Section: B Radiometric Calibration Based On Natural Point Targetsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthetic Aperture Radar Radiometric Cross Calibration Based on Distributed Targets

Zhou

Duan

et al. 2022

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

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Accuracy Analysis of Radiometric Calibration In-Orbit for SuperView Neo-2 SAR Satellite

Li,

Zhang,

Chen

et al. 2024

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

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The radiometric calibration technique of spaceborne synthetic aperture radar (SAR) aims to establish a constant relationship between the SAR target pulse response energy and the actual radar cross-section (RCS) of the ground. It is an essential technology for achieving quantitative observations of the Earth using radar. In this article, the process of in-orbit radiometric calibration campaign for the SuperView Neo-2 SAR satellite is introduced, which is the distributed X-band SAR satellite in the new generation of Chinese SiWei commercial remote sensing satellite system. More specifically, the initial step involves deriving the total transfer function of the SAR system using the radar equation and establishing a stable calibration constant model for the SAR system. Further, by using the obtained calibration constant to invert the RCS value of the corner reflectors in the Otog Banner calibration field, while validating and analyzing the absolute radiometric accuracy. Considering that the elevation antenna pattern (EAP) predominantly affects the consistency of image radiometric correction, the method of extracting EAP and beam center bias angle from the rainforest is presented. Finally, the quality validation of impulse response function (IRF) is performed over the California calibration field, which can effectively guarantee the quality of SuperView Neo-2 SAR satellite products.

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Calibrator Position Error Compensation Method Based on Cross-Linear Scanning Strategy

Wu,

Zuo,

Guo

et al. 2024

Antennas Wirel. Propag. Lett.

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The Influence of the Azimuth RCS Pattern of Calibrator on SAR Absolute Calibration

Cited by 4 publications

References 13 publications

Synthetic Aperture Radar Radiometric Cross Calibration Based on Distributed Targets

Synthetic Aperture Radar Radiometric Cross Calibration Based on Distributed Targets

Accuracy Analysis of Radiometric Calibration In-Orbit for SuperView Neo-2 SAR Satellite

Calibrator Position Error Compensation Method Based on Cross-Linear Scanning Strategy

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