Investigation on Geometry Computation of Spaceborne GNSS-R Altimetry over Topography: Modeling and Validation

The space borne Global Navigation Satellite Systems Reflectometry (GNSS-R) offers versatile Earth surface observation. While the accuracy of the computed geometry, required for the implementation of the technique, degrades when Earth’s surface topography is complicated, previous studies ignored the...

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Detalhes bibliográficos
Autores: Song, Minfeng, He, Xiufeng, Asgarimehr, Milad, Li, Weiqiang, Xiao, Ruya, Jia, Dongzhen, Wang, Xiaolei, Wickert, Jens
Tipo de documento: artigo
Estado:Versão publicada
Data de publicação:2022
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositório:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/279885
Acesso em linha:http://hdl.handle.net/10261/279885
Access Level:Acceso aberto
Palavra-chave:GNSS reflectometry
Geometry computation
Topography slope
Specular point
Surface height estimation
Greenland
TDS-1
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spelling Investigation on Geometry Computation of Spaceborne GNSS-R Altimetry over Topography: Modeling and ValidationSong, MinfengHe, XiufengAsgarimehr, MiladLi, WeiqiangXiao, RuyaJia, DongzhenWang, XiaoleiWickert, JensGNSS reflectometryGeometry computationTopography slopeSpecular pointSurface height estimationGreenlandTDS-1ddc:620The space borne Global Navigation Satellite Systems Reflectometry (GNSS-R) offers versatile Earth surface observation. While the accuracy of the computed geometry, required for the implementation of the technique, degrades when Earth’s surface topography is complicated, previous studies ignored the effects of the local terrain surrounding the ideal specular point at a suppositional Earth reference surface. The surface slope and its aspect have been confirmed that it can lead to geolocation-related errors in the traditional radar altimetry, which will be even more intensified in tilt observations. In this study, the effect of large-scale slope on the spaceborne GNSS-R technique is investigated. We propose a new geometry computation strategy based on the property of ellipsoid to carry out forward and inverse calculations of path geometries. Moreover, it can be extended to calculate unusual reflected paths over versatile Earth’s topography by taking the surface slope and aspects into account. A simulation considering the slope effects demonstrates potential errors as large as meters to tens kilometers in geolocation and height estimations in the grazing observation condition over slopes. For validation, a single track over the Greenland surface received by the TechDemoSat 1 (TDS-1) satellite with a slope range from 0% to 1% was processed and analyzed. The results show that using the TanDEM-X 90 m Digital Elevation Model (DEM) as a reference, a slope of 0.6% at an elevation angle of 54 degrees can result in a geolocation inaccuracy of 10 km and a height error of 50 m. The proposed method in this study greatly reduces the standard deviation of geolocations of specular points from 4758 m to 367 m, and height retrievals from 28 m to 5.8 m. Applications associated with topography slopes, e.g., cryosphere could benefit from this method.This research was funded by the Natural Science Foundation of China (Grant No. 41830110 and No. 42174018), the Fundamental Research Funds for the Central Universities (Grant No. B200203110), Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX20_0489), and the State Scholarship Fund from Chinese Scholarship Council (No. 202006710115).Multidisciplinary Digital Publishing InstituteNational Natural Science Foundation of ChinaJiangsu ProvinceConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2022202220222022info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/279885reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://doi.org/10.3390/rs14092105Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2798852026-05-22T06:33:51Z
dc.title.none.fl_str_mv Investigation on Geometry Computation of Spaceborne GNSS-R Altimetry over Topography: Modeling and Validation
title Investigation on Geometry Computation of Spaceborne GNSS-R Altimetry over Topography: Modeling and Validation
spellingShingle Investigation on Geometry Computation of Spaceborne GNSS-R Altimetry over Topography: Modeling and Validation
Song, Minfeng
GNSS reflectometry
Geometry computation
Topography slope
Specular point
Surface height estimation
Greenland
TDS-1
ddc:620
title_short Investigation on Geometry Computation of Spaceborne GNSS-R Altimetry over Topography: Modeling and Validation
title_full Investigation on Geometry Computation of Spaceborne GNSS-R Altimetry over Topography: Modeling and Validation
title_fullStr Investigation on Geometry Computation of Spaceborne GNSS-R Altimetry over Topography: Modeling and Validation
title_full_unstemmed Investigation on Geometry Computation of Spaceborne GNSS-R Altimetry over Topography: Modeling and Validation
title_sort Investigation on Geometry Computation of Spaceborne GNSS-R Altimetry over Topography: Modeling and Validation
dc.creator.none.fl_str_mv Song, Minfeng
He, Xiufeng
Asgarimehr, Milad
Li, Weiqiang
Xiao, Ruya
Jia, Dongzhen
Wang, Xiaolei
Wickert, Jens
author Song, Minfeng
author_facet Song, Minfeng
He, Xiufeng
Asgarimehr, Milad
Li, Weiqiang
Xiao, Ruya
Jia, Dongzhen
Wang, Xiaolei
Wickert, Jens
author_role author
author2 He, Xiufeng
Asgarimehr, Milad
Li, Weiqiang
Xiao, Ruya
Jia, Dongzhen
Wang, Xiaolei
Wickert, Jens
author2_role author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv National Natural Science Foundation of China
Jiangsu Province
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv GNSS reflectometry
Geometry computation
Topography slope
Specular point
Surface height estimation
Greenland
TDS-1
ddc:620
topic GNSS reflectometry
Geometry computation
Topography slope
Specular point
Surface height estimation
Greenland
TDS-1
ddc:620
description The space borne Global Navigation Satellite Systems Reflectometry (GNSS-R) offers versatile Earth surface observation. While the accuracy of the computed geometry, required for the implementation of the technique, degrades when Earth’s surface topography is complicated, previous studies ignored the effects of the local terrain surrounding the ideal specular point at a suppositional Earth reference surface. The surface slope and its aspect have been confirmed that it can lead to geolocation-related errors in the traditional radar altimetry, which will be even more intensified in tilt observations. In this study, the effect of large-scale slope on the spaceborne GNSS-R technique is investigated. We propose a new geometry computation strategy based on the property of ellipsoid to carry out forward and inverse calculations of path geometries. Moreover, it can be extended to calculate unusual reflected paths over versatile Earth’s topography by taking the surface slope and aspects into account. A simulation considering the slope effects demonstrates potential errors as large as meters to tens kilometers in geolocation and height estimations in the grazing observation condition over slopes. For validation, a single track over the Greenland surface received by the TechDemoSat 1 (TDS-1) satellite with a slope range from 0% to 1% was processed and analyzed. The results show that using the TanDEM-X 90 m Digital Elevation Model (DEM) as a reference, a slope of 0.6% at an elevation angle of 54 degrees can result in a geolocation inaccuracy of 10 km and a height error of 50 m. The proposed method in this study greatly reduces the standard deviation of geolocations of specular points from 4758 m to 367 m, and height retrievals from 28 m to 5.8 m. Applications associated with topography slopes, e.g., cryosphere could benefit from this method.
publishDate 2022
dc.date.none.fl_str_mv 2022
2022
2022
2022
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/279885
url http://hdl.handle.net/10261/279885
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://doi.org/10.3390/rs14092105
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Multidisciplinary Digital Publishing Institute
publisher.none.fl_str_mv Multidisciplinary Digital Publishing Institute
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,812455

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