An Improved Geometric Calibration Model for Spaceborne SAR Systems With a Case Study of Large-Scale Gaofen-3 Images

Feng, Yongjiu; Lei, Zhenkun; Tong, Xiaohua; Xi, Mengrong; Li, Pengshuo

doi:10.1109/jstars.2022.3198414

Cited by 7 publications

(6 citation statements)

References 58 publications

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“…where P surf is surface pressure, P w is precipitation, T is thermodynamic temperature, h is ground elevation, and w is relative humidity (typically 0.7) (Feng et al, 2022). The proposed estimation method for atmospheric propagation delay can be used to solve the systematic time delay and compensate for the systematic time delay.…”

Section: Iterative Compensation Methods Of Atmospheric Propagation De...mentioning

confidence: 99%

“…As shown in Figure 4, the stereo image pairs were first constructed using two SAR images, and homologous image points were extracted to realize stereo positioning. SAM (Feng et al., 2022; Fernandes et al., 2021) was used to calculate surface pressure and atmospheric precipitation based on ground elevation obtained from stereo positioning. The tropospheric atmospheric propagation delay can be calculated from the tropospheric atmospheric propagation delay correction model (Owens, 1967) based on surface pressure and atmospheric precipitation.…”

Section: Methods and Principlesmentioning

confidence: 99%

“…The SAM (Feng et al., 2022; Fernandes et al., 2021) can be calculated as:

({, \begin{matrix} P_{surf} goodbreak= 1013.25 goodbreak\times {(1 - 2.2557 \times 10^{- 5} \cdot h)}^{5.2568} \\ T goodbreak= 15.0 goodbreak- 6.5 goodbreak\times 10^{- 3} \cdot h goodbreak+ 273.15 \\ P_{w} goodbreak= 6.108 goodbreak\times e^{\frac{17.15 T - 4684.0}{T - 38.45}} goodbreak\times w \end{matrix})

where P surf is surface pressure, P w is precipitation, T is thermodynamic temperature, h is ground elevation, and w is relative humidity (typically 0.7) (Feng et al., 2022). The proposed estimation method for atmospheric propagation delay can be used to solve the systematic time delay and compensate for the systematic time delay.…”

Section: Methods and Principlesmentioning

confidence: 99%

“…In addition, the stereo positioning accuracy of SAR satellites is affected by atmospheric propagation delays. Currently, methods for estimating atmospheric propagation delays can be divided into those based on atmospheric param (Jehle et al., 2008, 2010; Owens, 1967; Schubert et al., 2010) and those based on empirical models (Feng et al., 2022; Fernandes et al., 2021). Real‐time atmospheric products estimate the atmospheric propagation delay when using atmospheric param.…”

Section: Introductionmentioning

confidence: 99%

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Improvement of the spaceborne synthetic aperture radar stereo positioning accuracy without ground control points

Wei,

Zhao,

Fan

et al. 2024

The Photogrammetric Record

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Compared with optical remote sensing satellites, the geometric positioning accuracy of synthetic aperture radar (SAR) satellite is not affected by satellite attitude or weather conditions. SAR satellites can achieve relatively high positioning accuracy without ground control points, which is particularly important in global surveying and mapping. However, the stereo positioning accuracy of SAR satellites is mainly affected by the SAR systematic delay and the atmospheric propagation delay of radar signals. An iterative compensation method for the SAR systematic time delay is proposed based on digital elevation model to improve the stereo positioning accuracy of SAR satellites without control points. In addition, to address the non‐real‐time updates of external reference atmospheric param, an iterative compensation method to estimate the atmospheric propagation delay of radar signals is proposed based on standard atmospheric models. In this study, SAR images from the Gaofen‐3 (GF‐3) satellite with 5 m resolutions were used as experimental data to verify the effectiveness of our proposed method. Simultaneously, the 2D positioning accuracy was better than 3 m and increased by 42.9%, and the elevation positioning accuracy was better than 3 m and increased by 90.2%.

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Section: Iterative Compensation Methods Of Atmospheric Propagation De...mentioning

confidence: 99%

Section: Methods and Principlesmentioning

confidence: 99%

“…The SAM (Feng et al., 2022; Fernandes et al., 2021) can be calculated as:

({, \begin{matrix} P_{surf} goodbreak= 1013.25 goodbreak\times {(1 - 2.2557 \times 10^{- 5} \cdot h)}^{5.2568} \\ T goodbreak= 15.0 goodbreak- 6.5 goodbreak\times 10^{- 3} \cdot h goodbreak+ 273.15 \\ P_{w} goodbreak= 6.108 goodbreak\times e^{\frac{17.15 T - 4684.0}{T - 38.45}} goodbreak\times w \end{matrix})

Section: Methods and Principlesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Improvement of the spaceborne synthetic aperture radar stereo positioning accuracy without ground control points

Wei,

Zhao,

Fan

et al. 2024

The Photogrammetric Record

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show abstract

“…These errors typically exhibit a constant character and necessitate detection through geometric calibration [2]. Geometric calibration estimates systematic time errors by comparing SAR image parameters with reference data, such as corner reflectors (CRs) and digital orthophoto maps (DOMs) [3].…”

Section: Introductionmentioning

confidence: 99%

First Assessment of Bistatic Geometric Calibration and Geolocation Accuracy of Innovative Spaceborne Synthetic Aperture Radar LuTan-1

Mou,

Wang,

Hong

et al. 2023

Remote Sensing

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LuTan-1 (LT-1) is a bistatic synthetic aperture radar (BiSAR) system consisting of two identical L-band SAR satellites. The bistatic mode of LT-1 plays a critical role in generating high-precision digital elevation models (DEMs), which requires precise geometric calibration of initial range and azimuth times for both SARs to ensure the reliability and quality of geolocation. However, existing geometric calibration methods predominantly focus on monostatic SAR systems, with limited literature on slave SAR calibration in bistatic systems. This research addresses this gap by establishing geometric calibration models for both SARs based on signal echo history and the range–Doppler model. The geometric errors are effectively resolved using corner reflector data from Xinjiang, China. Through statistical analysis of LT-1 SAR images acquired between July and November in bistatic mode, this paper has demonstrated range delay accuracy of better than 5 ns and azimuth time accuracy of better than 0.1 ms. This level of precision translates into a positional accuracy better than 0.8 m. The proposed models have been successfully applied to geometric calibration, providing precise geolocation for LT-1, thus enhancing its utility for a wide range of Earth observation applications. This paper is the first endeavor to present the assessment of the geometric calibration and geolocation accuracy of LT-1 and discuss the results of the bistatic geometric calibration of the master and slave SARs in a BiSAR formation.

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Radar vegetation indices for monitoring surface vegetation: Developments, challenges, and trends

Hu,

Li,

Huang

et al. 2024

Science of The Total Environment

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An Improved Geometric Calibration Model for Spaceborne SAR Systems With a Case Study of Large-Scale Gaofen-3 Images

Cited by 7 publications

References 58 publications

Improvement of the spaceborne synthetic aperture radar stereo positioning accuracy without ground control points

Improvement of the spaceborne synthetic aperture radar stereo positioning accuracy without ground control points

First Assessment of Bistatic Geometric Calibration and Geolocation Accuracy of Innovative Spaceborne Synthetic Aperture Radar LuTan-1

Radar vegetation indices for monitoring surface vegetation: Developments, challenges, and trends

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