Study on the geolocation accuracy of SAR corner reflectors in the mountain and canyon region: a case study of a giant hydropower station reservoir head area

doi:10.13474/j.cnki.11-2246.2025.0604

Abstract

Abstract: Corner reflectors(CR)serve as a crucial tool for high-precision interferometric synthetic aperture radar (InSAR) monitoring, with their reflective performance and geolocation accuracy playing a key role in InSAR deformation monitoring and result interpretation. Existing research on CR geolocation accuracy focuses on flat terrain, lacking studies addressing complex topographical settings. This paper presents a comprehensive method for CR geolocation accuracy analysis, combining SAR geolocation and radar cross section (RCS) analysis techniques, and validated using the CR array deployed at a mountainous reservoir head area of a giant hydropower station located within a river canyon. Results indicate that out of the 10 corner reflectors (CRs) in the reservoir head area, 8 exhibits good accuracy, while 2 demonstrates suboptimal precision. The RCS of the 8 high-precision CRs increases by over 5 dBm² after installation, with an average increase of 10.24 dBm², representing an average growth of 66.2%, and the average SAR geolocation errors in the azimuth and range directions are -0.601 and -0.013 m, respectively. The accuracy of the 2 remaining CRs is limited due to the foreshortening effect, with SAR geolocation errors in the azimuth direction of 5.83 and -9.02 m, and range errors of 1.37 and -0.73 m respectively, highlighting that terrain complexity should be taken into consideration when deploying CRs in mountainous canyon regions. The findings of this study provide the first evaluation of the applicability of SAR geolocation in mountain and canyon scenarios and offer crucial insights into the accuracy of the CR array at the giant hydropower station reservoir head area, providing important references for high-precision InSAR deformation monitoring and result interpretation in mountainous canyon regions.

Key words: hydropower station, synthetic aperture radar, corner reflector, SAR geolocation, radar cross section, Sentinel-1

CLC Number:

P237

FAN Jinyong, LIAO Haisheng, CHEN Jian, HE Xin, LUO Huiheng, HUANG Rong, YANG Lei, LI Linze, CHEN Yaowen, JIANG Liming, HUANG Ronggang. Study on the geolocation accuracy of SAR corner reflectors in the mountain and canyon region: a case study of a giant hydropower station reservoir head area[J]. Bulletin of Surveying and Mapping, 2025, 0(6): 18-23.

References

[1] CHEN Yaowen,HUANG Qihuan,ZHANG Tingbin,et al.Measurement refinements of ground-based radar interferometry in bridge load test monitoring: comprehensive analysis on a multi-span cable-stayed bridge[J].Remote Sensing,2024,16(11): 1882.
[2] TARCHI D,RUDOLF H,LUZI G,et al.SAR interferometry for structural changes detection: a demonstration test on a dam[C]//Proceedings of 1999 IEEE International Geoscience and Remote Sensing Symposium.Hamburg:IEEE,1999: 1522-1524.
[3] WANG Teng,PERISSIN D,ROCCA F,et al.Three Gorges Dam stability monitoring with time-series InSAR image analysis[J].Science China Earth Sciences,2011,54(5): 720-732.
[4] 戴可人,沈月,吴明堂,等.联合InSAR与无人机航测的白鹤滩库区蓄水前地灾隐患广域识别[J].测绘学报,2022,51(10): 2069-2082.
[5] ZHOU Chao,CAO Ying,HU Xie,et al.Enhanced dynamic landslide hazard mapping using MT-InSAR method in the Three Gorges Reservoir Area[J].Landslides,2022,19(7): 1585-1597.
[6] 廖明生,王腾.时间序列InSAR技术与应用[M].北京: 科学出版社,2014.
[7] CZIKHARDT R,VAN DER MAREL H,VAN LEIJEN F J,et al.Estimating signal-to-clutter ratio of InSAR corner reflectors from SAR time series[J].IEEE Geoscience and Remote Sensing Letters,2022,19: 3070045.
[8] GARTHWAITE M C.On the design of radar corner reflectors for deformation monitoring in multi-frequency InSAR[J].Remote Sensing,2017,9(7): 648.
[9] LI Chengfan,YIN Jingyuan,ZHAO Junjuan,et al.The selection of artificial corner reflectors based on RCS analysis[J].Acta Geophysica,2012,60(1): 43-58.
[10] GISINGER C,SCHUBERT A,BREIT H,et al.In-depth verification of Sentinel-1 and TerraSAR-X geolocation accuracy using the Australian corner reflector array[J].IEEE Transactions on Geoscience and Remote Sensing,2021,59(2): 1154-1181.
[11] 王赛,孟欣,楼良盛,等.天绘二号卫星单幅SAR影像定位性能评估[J].测绘学报,2022,51(12): 2501-2507.
[12] CURLANDER J C.Location of spaceborne SAR imagery[J].IEEE Transactions on Geoscience and Remote Sensing,1982,20(3): 359-364.
[13] CHEN P H,DOWMAN I J.Space intersection from ERS-1 synthetic aperture radar images[J].The Photogrammetric Record,1996,15(88): 561-573.
[14] CHEN Puhuai,DOWMAN I J.A weighted least squares solution for space intersection of spaceborne stereo SAR data[J].IEEE Transactions on Geoscience and Remote Sensing,2001,39(2): 233-240.
[15] RAGGAM H,PERKO R,GUTJAHR K,et al.Accuracy assessment of 3D point retrieval from TerraSAR-X data sets[C]//Proceedings of the 8th European Conference on Synthetic Aperture Radar.Aachen:IEEE,2010.
[16] EINEDER M,MINET C,STEIGENBERGER P,et al.Imaging geodesy: toward centimeter-level ranging accuracy with TerraSAR-X[J].IEEE Transactions on Geoscience and Remote Sensing,2011,49(2): 661-671.
[17] HERSBACH H,BELL B,BERRISFORD P,et al.The ERA5 global reanalysis[J].Quarterly Journal of the Royal Meteorological Society,2020,146(730): 1999-2049.
[18] HERNÁNDEZ-PAJARES M,JUAN J M,SANZ J,et al.The IGS VTEC maps: a reliable source of ionospheric information since 1998[J].Journal of Geodesy,2009,83(3): 263-275.
[19] MCCARTHY D D,PETIT G.IERS conventions (2003) [M].Frankfurt am Main:Bundesamt für Kartographie und Geodäsie,2004.
[20] CZIKHARDT R,VAN DER MAREL H,PAPCO J.GECORIS: an open-source toolbox for analyzing time series of corner reflectors in InSAR geodesy[J].Remote Sensing,2021,13(5): 926.