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Spheroidal spline interpolation and its application in geodesy / Mostafa Kiani in Geodesy and cartography, vol 46 n° 3 (October 2020)
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Titre : Spheroidal spline interpolation and its application in geodesy Type de document : Article/Communication Auteurs : Mostafa Kiani, Auteur ; Nabi Chegini, Auteur ; Abdolreza Safari, Auteur Année de publication : 2020 Article en page(s) : pp 123 - 135 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse harmonique
[Termes IGN] espace de Hilbert
[Termes IGN] fonction de Green
[Termes IGN] fonction spline d'interpolation
[Termes IGN] force de gravitation
[Termes IGN] optimisation (mathématiques)
[Termes IGN] sphèroïdeRésumé : (auteur) The aim of this paper is to study the spline interpolation problem in spheroidal geometry. We follow the minimization of the norm of the iterated Beltrami-Laplace and consecutive iterated Helmholtz operators for all functions belong-ing to an appropriate Hilbert space defined on the spheroid. By exploiting surface Green’s functions, reproducing kernels for discrete Dirichlet and Neumann conditions are constructed in the spheroidal geometry. According to a complete system of surface spheroidal harmonics, generalized Green’s functions are also defined. Based on the minimization problem and corresponding reproducing kernel, spline interpolant which minimizes the desired norm and satisfies the given discrete conditions is defined on the spheroidal surface. The application of the results in Geodesy is explained in the gravity data interpolation over the globe. Numéro de notice : A2020-783 Affiliation des auteurs : non IGN Thématique : MATHEMATIQUE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3846/gac.2020.11316 En ligne : https://doi.org/10.3846/gac.2020.11316 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96479
in Geodesy and cartography > vol 46 n° 3 (October 2020) . - pp 123 - 135[article]Study on the inter-annual hydrology-induced deformations in Europe using GRACE and hydrological models / Artur Lenczuk in Journal of applied geodesy, vol 14 n° 4 (October 2020)
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Titre : Study on the inter-annual hydrology-induced deformations in Europe using GRACE and hydrological models Type de document : Article/Communication Auteurs : Artur Lenczuk, Auteur ; Grzegorz Leszczuk, Auteur ; Anna Klos, Auteur Année de publication : 2020 Article en page(s) : pp 393 – 403 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] amplitude
[Termes IGN] analyse de spectre singulier
[Termes IGN] bassin hydrographique
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données GLDAS
[Termes IGN] données GRACE
[Termes IGN] Europe (géographie politique)
[Termes IGN] modèle hydrographique
[Termes IGN] surcharge hydrologique
[Termes IGN] variation saisonnièreRésumé : (auteur) Earth’s crust deforms in various time and spatial resolutions. To estimate them, geodetic observations are widely employed and compared to geophysical models. In this research, we focus on the Earth’s crust deformations resulting from hydrology mass changes, as observed by GRACE (Gravity Recovery and Climate Experiment) gravity mission and modeled using WGHM (WaterGAP Global Hydrological Model) and GLDAS (Global Land Data Assimilation System), hydrological models. We use the newest release of GRACE Level-2 products, i. e. RL06, provided by the CSR (Center for Space Research, Austin) analysis center in the form of a mascon solution. The analysis is performed for the European area, divided into 29 river basins. For each basin, the average signal is estimated. Then, annual amplitudes and trends are calculated. We found that the eastern part of Europe is characterized by the largest annual amplitudes of hydrology-induced Earth’s crust deformations, which decrease with decreasing distance to the Atlantic coast. GLDAS largely overestimates annual amplitudes in comparison to GRACE and WGHM. Hydrology models underestimate trends, which are observed by GRACE. For the basin-related average signals, we also estimate the non-linear variations over time using the Singular Spectrum Analysis (SSA). For the river basins situated on the southern borderline of Europe and Asia, large inter-annual deformations between 2004 and 2009 reaching a few millimeters are found; they are related to high precipitation and unexpectedly large drying. They were observed by GRACE but mismodelled in the GLDAS and WGHM models. Few smaller inter-annual deformations were also observed by GRACE between 2002-2017 for central and eastern European river basins, but these have been also well-covered by the WGHM and GLDAS hydrological models. Numéro de notice : A2020-677 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2020-0017 Date de publication en ligne : 27/10/2020 En ligne : https://doi.org/10.1515/jag-2020-0017 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96170
in Journal of applied geodesy > vol 14 n° 4 (October 2020) . - pp 393 – 403[article]Background tropospheric delay in geosynchronous synthetic aperture radar / Dexin Li in Remote sensing, vol 12 n° 18 (September-2 2020)
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Titre : Background tropospheric delay in geosynchronous synthetic aperture radar Type de document : Article/Communication Auteurs : Dexin Li, Auteur ; Xiaoxiang Zhu, Auteur ; Zhen Dong, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : 21 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] compensation
[Termes IGN] décorrélation
[Termes IGN] données météorologiques
[Termes IGN] image à haute résolution
[Termes IGN] image radar moirée
[Termes IGN] modèle géométrique de prise de vue
[Termes IGN] propagation troposphérique
[Termes IGN] radar bistatique
[Termes IGN] retard troposphérique
[Termes IGN] synchronisationRésumé : (auteur) Spaceborne synthetic aperture radar (SAR) has been treated as a weather independent system for a long time. However, with the development of advanced SAR configurations, e.g., high resolution, bistatic, geosynchronous (GEO), the influence of tropospheric propagation error, which strongly depends on the weather, has begun to receive attention. In this paper, we focus on the effect of deterministic background tropospheric delay (BTD) during the image formation of GEO SAR. First, the decorrelation problems caused by the spatial variation and BTD are presented. Second, by combining with the SAR imaging geometry, the BTD error is decomposed as constant error, spatially variant error, and time variant error, the influences of which are analyzed under different circumstances. Third, an imaging method starting from the meteorological parameters and the GEO SAR systematic parameters is proposed to deal with the decorrelation problems. Finally, simulations with the dot-matrix targets are performed to validate the imaging method. Numéro de notice : A2020-632 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.3390/rs12183081 Date de publication en ligne : 20/09/2020 En ligne : https://doi.org/10.3390/rs12183081 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96053
in Remote sensing > vol 12 n° 18 (September-2 2020) . - 21 p.[article]Benefits of non-tidal loading applied at distinct levels in VLBI analysis / Matthias Glomsda in Journal of geodesy, vol 94 n° 9 (September 2020)
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Titre : Benefits of non-tidal loading applied at distinct levels in VLBI analysis Type de document : Article/Communication Auteurs : Matthias Glomsda, Auteur ; Mathis Blossfeld, Auteur ; Manuela Seitz, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : n° 90 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données ITGB
[Termes IGN] effet de charge
[Termes IGN] interférométrie à très grande base
[Termes IGN] pesanteur hors marée
[Termes IGN] retard troposphérique
[Termes IGN] série temporelle
[Termes IGN] surcharge hydrologique
[Termes IGN] surcharge océanique
[Termes IGN] transformation de HelmertRésumé : (auteur) In the analysis of very long baseline interferometry (VLBI) observations, many geophysical models are used for correcting the theoretical signal delay. In addition to the conventional models described by Petit and Luzum (eds) (IERS Conventions, 2010), we are applying different parts of non-tidal site loading, namely the atmospheric, oceanic, and hydrological ones. To investigate their individual contributions, these parts are considered both separately and combined to a total loading. The application of the corresponding site displacements is performed at two distinct levels of the geodetic parameter estimation process (observation and normal equation level), which turn out to give very similar results in many cases. To validate our findings internally, the site displacements are provided by two different data centres: the Earth-System-Modelling group at the Deutsches GeoForschungsZentrum in Potsdam (ESMGFZ, see Dill and Dobslaw, J Geophys Res Solid Earth, 2013. https://doi.org/10.1002/jgrb.50353ISTEX)] and the International Mass Loading Service [IMLS, see Petrov (The international mass loading service, 2015)]. We show that considering non-tidal loading is actually useful for mitigating systematic effects in the VLBI results, like annual signals in the station height time series. If the sum of all non-tidal loading parts is considered, the WRMS of the station heights and baseline lengths is reduced in 80–90% of all cases, and the relative improvement is about −3.5% on average. The main differences between our chosen providers originate from hydrological loading. Numéro de notice : A2020-540 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01418-z Date de publication en ligne : 31/08/2020 En ligne : https://doi.org/10.1007/s00190-020-01418-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95741
in Journal of geodesy > vol 94 n° 9 (September 2020) . - n° 90[article]Estimating ocean tide loading displacements with GPS and GLONASS / Bogdan Matviichuk in Solid Earth, vol 11 n° 5 (September - October 2020)
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Titre : Estimating ocean tide loading displacements with GPS and GLONASS Type de document : Article/Communication Auteurs : Bogdan Matviichuk, Auteur ; Matt A. King, Auteur ; Christopher S. Watson, Auteur Année de publication : 2020 Article en page(s) : pp 1849 - 1863 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] données GLONASS
[Termes IGN] données GPS
[Termes IGN] estimation de position
[Termes IGN] surcharge océaniqueRésumé : (auteur) Ground displacements due to ocean tide loading have previously been successfully observed using Global Positioning System (GPS) data, and such estimates for the principal lunar M2 constituent have been used to infer the rheology and structure of the asthenosphere. The GPS orbital repeat period is close to that of several other major tidal constituents (K1, K2, S2); thus, GPS estimates of ground displacement at these frequencies are subject to GPS systematic errors. We assess the addition of GLONASS (GLObal NAvigation Satellite System) to increase the accuracy and reliability of eight major ocean tide loading constituents: four semi-diurnal (M2, S2, N2, K2) and four diurnal constituents (K1, O1, P1, Q1). We revisit a previous GPS study, focusing on 21 sites in the UK and western Europe, expanding it with an assessment of GLONASS and GPS+GLONASS estimates. In the region, both GPS and GLONASS data have been abundant since 2010.0. We therefore focus on the period 2010.0–2014.0, a span considered long enough to reliably estimate the major constituents. Data were processed with a kinematic precise point positioning (PPP) strategy to produce site coordinate time series for each of three different modes: GPS, GLONASS and GPS+GLONASS. The GPS solution with ambiguities resolved was used as a baseline for performance assessment of the additional modes. GPS+GLONASS shows very close agreement with ambiguity resolved GPS for lunar constituents (M2, N2, O1, Q1) but with substantial differences for solar-related constituents (S2, K2, K1, P1), with solutions including GLONASS being generally closer to model estimates. While no single constellation mode performs best for all constituents and components, we propose to use a combination of constellation modes to recover tidal parameters: GPS+GLONASS for most constituents, except for K2 and K1 where GLONASS (north and up) and GPS with ambiguities resolved (east) perform best. Numéro de notice : A2020-837 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.5194/se-11-1849-2020 Date de publication en ligne : 14/10/2020 En ligne : https://doi.org/10.5194/se-11-1849-2020 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98169
in Solid Earth > vol 11 n° 5 (September - October 2020) . - pp 1849 - 1863[article]Genèse d'une norme internationale géodésique : l'ITRS et ses réalisations / Thierry Gattacceca in XYZ, n° 164 (septembre 2020)
PermalinkGNSS scale determination using calibrated receiver and Galileo satellite antenna patterns / Arturo Villiger in Journal of geodesy, vol 94 n° 9 (September 2020)
PermalinkGRACE-FO precise orbit determination and gravity recovery / Z. Kang in Journal of geodesy, vol 94 n° 9 (September 2020)
PermalinkMonitoring the deformation of a concrete dam: a case study on the Deriner Dam, Artvin, Turkey / Berkant Konakoglu in Geomatics, Natural Hazards and Risk, vol 11 n° 1 (2020)
PermalinkPermalinkAmbiguous use of geographical information systems for the rectification of large-scale geometric maps / Anders Wästfelt in Cartographic journal (the), Vol 57 n° 3 (August 2020)
PermalinkAn assessment of wide-lane ambiguity resolution methods for multi-frequency multi-GNSS precise point positioning / Viet Duong in Survey review, vol 52 n° 374 (August 2020)
PermalinkEvaluation of single-frequency receivers for studying crustal deformation at the longitudinal Valley fault, eastern Taiwan / Horng-Yue Chen in Survey review, vol 52 n° 374 (August 2020)
PermalinkGipsyX/RTGx, a new tool set for space geodetic operations and research / Willy I. Bertiger in Advances in space research, vol 66 n° 3 (1 August 2020)
PermalinkIntegration of airborne gravimetry data filtering into residual least-squares collocation: example from the 1 cm geoid experiment / Martin Willberg in Journal of geodesy, vol 94 n° 8 (August 2020)
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