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The direct geodesic problem and an approximate analytical solution in Cartesian coordinates on a triaxial ellipsoid / Georgios Panou in Journal of applied geodesy, vol 14 n° 2 (April 2020)  

Public [article]  inJournal of applied geodesy > vol 14 n° 2 (April 2020) . - pp 205 – 213 Titre : The direct geodesic problem and an approximate analytical solution in Cartesian coordinates on a triaxial ellipsoid Type de document : Article/Communication Auteurs : Georgios Panou, Auteur ; Romylos Korakitis, Auteur Année de publication : 2020 Article en page(s) : pp 205 – 213 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie [Termes descripteurs IGN] coordonnées cartésiennes [Termes descripteurs IGN] coordonnées ellipsoïdales [Termes descripteurs IGN] données géodésiques [Termes descripteurs IGN] ellipsoïde (géodésie) [Termes descripteurs IGN] géométrie analytique [Termes descripteurs IGN] série de Taylor [Termes descripteurs IGN] sphèroïde [Termes descripteurs IGN] transformation de coordonnées Résumé : (auteur) In this work, the direct geodesic problem in Cartesian coordinates on a triaxial ellipsoid is solved by an approximate analytical method. The parametric coordinates are used and the parametric to Cartesian coordinates conversion and vice versa are presented. The geodesic equations on a triaxial ellipsoid in Cartesian coordinates are solved using a Taylor series expansion. The solution provides the Cartesian coordinates and the angle between the line of constant v and the geodesic at the end point. An extensive data set of geodesics, previously studied with a numerical method, is used in order to validate the presented analytical method in terms of stability, accuracy and execution time. We conclude that the presented method is suitable for a triaxial ellipsoid with small eccentricities and an accurate solution is obtained. At a similar accuracy level, this method is about thirty times faster than the corresponding numerical method. Finally, the presented method can also be applied in the degenerate case of an oblate spheroid, which is extensively used in geodesy. Numéro de notice : A2020-218 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2019-0066 date de publication en ligne : 12/02/2020 En ligne : https://doi.org/10.1515/jag-2019-0066 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94911 [article]

Implementation of the new Slovenian Height System (SVS2010) / Klemen Medved in Geodetski vestnik, Vol 64 n° 1 (March - May 2020)  

Public [article]  inGeodetski vestnik > Vol 64 n° 1 (March - May 2020) . - 10 p. Titre : Implementation of the new Slovenian Height System (SVS2010) Type de document : Article/Communication Auteurs : Klemen Medved, Auteur ; Klemen Kozmus Trajkovski, Auteur ; Sandi Berk, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : 10 p. Note générale : bibliographie Langues : Anglais (eng) Slovène (slv) Descripteur : [Vedettes matières IGN] Nivellement [Termes descripteurs IGN] arpentage [Termes descripteurs IGN] données marégraphiques [Termes descripteurs IGN] géoïde altimétrique [Termes descripteurs IGN] Slovénie [Termes descripteurs IGN] système de référence altimétrique Résumé : (auteur) Recently, a new national height reference system was implemented: the Slovenian Height System 2010 (SVS2010). This new system replaced the Slovenian Height System 2000 (SVS2000). It is a new realisation of a national height system, which is based on new levelling and gravity surveys and recent tide gauge data. Its implementation changes the height datum (from Trieste to Koper) as well as the type of heights (from normal-orthometric to normal). Consequently, differences between the old and new height reference systems from 1.4 cm to 30.8 cm were detected. Unfortunately, there is no simple transformation between the two height reference systems. The surveyor must choose an appropriate method of local transformation or recalculation based on the given data and the required accuracy. To provide all necessary information for the users, the Surveying and Mapping Authority of the Republic of Slovenia has, in cooperation with the Faculty of Civil and Geodetic Engineering at the University of Ljubljana, prepared a new Technical instruction for the use of the new national height system. Online software called SiVis is also available for converting GNSS-based heights into both height reference systems (SVS2000 and SVS2010). Due to some problems with the (old) AMG2000/Trst geoid model near the national boundary, this model was extrapolated to a buffer covering parts of neighbouring countries. EPSG codes for both national height reference systems of Slovenia were also created Numéro de notice : A2020-275 Thématique : POSITIONNEMENT Nature : Article DOI : 10.15292/geodetski-vestnik.2020.01.33-42 date de publication en ligne : 06/03/2020 En ligne : https://doi.org/10.15292/geodetski-vestnik.2020.01.33-42 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95072 [article]

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Validation of marine geoid models by utilizing hydrodynamic model and shipborne GNSS profiles / Sander Varbla in Marine geodesy, Vol 43 n° 2 (March 2020)  

Public [article]  inMarine geodesy > Vol 43 n° 2 (March 2020) . - pp 134 - 162 Titre : Validation of marine geoid models by utilizing hydrodynamic model and shipborne GNSS profiles Type de document : Article/Communication Auteurs : Sander Varbla, Auteur ; Artu Ellmann, Auteur ; Nicole Delpeche-Ellmann, Auteur Année de publication : 2020 Article en page(s) : pp 134 - 162 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] Baltique, mer [Termes descripteurs IGN] données marégraphiques [Termes descripteurs IGN] force de gravitation [Termes descripteurs IGN] geoïde marin [Termes descripteurs IGN] instrument embarqué [Termes descripteurs IGN] instrumentation GNSS [Termes descripteurs IGN] levé gravimétrique [Termes descripteurs IGN] navire [Termes descripteurs IGN] niveau de la mer [Termes descripteurs IGN] simulation hydrodynamique Résumé : (auteur) An essential role of the FAMOS international cooperation project is to obtain new marine gravity observations over the Baltic Sea for improving gravimetric geoid modelling. To achieve targeted 5 cm modelling accuracy, it is important to acquire new gravimetric data, as the existing data over some regions are inaccurate and sparse. As the accuracy of contemporary geoid models over marine areas remains unknown, it is important to evaluate geoid modelling outcome by independent data. Thus, this study presents results of a shipborne marine gravity and GNSS campaign for validation of existing geoid models conducted in the eastern section of the Baltic Sea. Challenging aspects for utilizing shipborne GNSS profiles tend to be with quantifying vessel’s attitude, processing of noise in the data and referencing to the required datum. Consequently, the novelty of this study is in the development of methodology that considers the above-mentioned challenges. In addition, tide gauge records in conjunction with an operational hydrodynamic model are used to identify offshore sea level dynamics during the marine measurements. The results show improvements in geoid modelling due to new marine gravimetric data. It is concluded that the marine GNSS profiles can potentially provide complementary constraints in problematic geoid modelling areas. Numéro de notice : A2020-051 Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/01490419.2019.1701153 date de publication en ligne : 20/01/2020 En ligne : https://doi.org/10.1080/01490419.2019.1701153 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94918 [article]

Assessment of ArcGIS based extraction of geoidal undulation compared to National Geospatial Intelligence Agency (NGA) model – A case study / Sher Muhammad in Journal of applied geodesy, vol 14 n° 1 (January 2020)  

Public [article]  inJournal of applied geodesy > vol 14 n° 1 (January 2020) . - pp 77 - 81 Titre : Assessment of ArcGIS based extraction of geoidal undulation compared to National Geospatial Intelligence Agency (NGA) model – A case study Type de document : Article/Communication Auteurs : Sher Muhammad, Auteur ; Lide Tian, Auteur Année de publication : 2020 Article en page(s) : pp 77 - 81 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] altitude orthométrique [Termes descripteurs IGN] détection d'erreur [Termes descripteurs IGN] Earth Gravity Model 1996 [Termes descripteurs IGN] ellipsoïde (géodésie) [Termes descripteurs IGN] géoïde altimétrique [Termes descripteurs IGN] Himalaya [Termes descripteurs IGN] interpolation [Termes descripteurs IGN] Matlab [Termes descripteurs IGN] modèle numérique de surface [Termes descripteurs IGN] niveau moyen des mers [Termes descripteurs IGN] Tibet Résumé : (auteur) Global Navigation Satellite System (GNSS) and remote sensing Digital Elevation Models (DEMs) represent earth’s surface elevation with reference to ellipsoid and orthometric heights. Proper estimation of the geoid (difference of ellipsoid and orthometric heights) is necessary before comparing data referenced to the different vertical datum. In this paper, an error in estimating EGM96 orthometric height is highlighted, verified by NGA/NASA developed model and MATLAB®. A significant error was found in the ArcGIS derived EGM96 orthometric heights range between ±6.9 meters. In addition, interpolation of low-resolution geoid data also produces significant biases depending on geographic location and the number of the interpolation data point. The bias was maximum negative in the central part of Tibetan Plateau and Himalaya. Therefore, estimation of orthometric height similar to NGA/NASA model precision is necessary for comparison of DEMs for natural resources management, 3D modelling and glaciers mass balance mainly in the mountainous regions. Numéro de notice : A2020-041 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2019-0030 En ligne : https://doi.org/10.1515/jag-2019-0030 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94512 [article]

Precise local quasigeoid modelling using GNSS/levelling height anomalies and gravity data / Marek Trojanowicz in Survey review, Vol 52 n°370 (January 2020)  

Public [article]  inSurvey review > Vol 52 n°370 (January 2020) . - pp 76 - 83 Titre : Precise local quasigeoid modelling using GNSS/levelling height anomalies and gravity data Type de document : Article/Communication Auteurs : Marek Trojanowicz, Auteur ; Edward Osada, Auteur ; Krzysztof Karsznia, Auteur Année de publication : 2020 Article en page(s) : pp 76 - 83 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] collocation par moindres carrés [Termes descripteurs IGN] données géophysiques [Termes descripteurs IGN] données GNSS [Termes descripteurs IGN] Earth Gravity Model 2008 [Termes descripteurs IGN] erreur en altitude [Termes descripteurs IGN] fonction spline d'interpolation [Termes descripteurs IGN] formule de Molodensky [Termes descripteurs IGN] modèle de géopotentiel local [Termes descripteurs IGN] modèle numérique de surface [Termes descripteurs IGN] nivellement [Termes descripteurs IGN] Pologne [Termes descripteurs IGN] quasi-géoïde Résumé : (auteur) This study compares four approaches of local quasigeoid modelling using GNSS/levelling height anomalies. The first two approaches utilise only a dense network of points with known GNSS/levelling height anomalies and the EGM2008 model. They are based on the interpolation of residual values of height anomalies by applying the least squares collocation (LSC) and the thin plate spline (TPS). The next two approaches use additional data in the form of surface gravity data and the digital elevation model. One of these approaches is based on the classical Molodensky method combined with LSC. The other approach utilises the method of geophysical gravity data inversion (GGI). During the research, the authors used a local network of points with precisely defined GNSS/levelling height anomalies located in South-Western Poland. They obtained comparable results for all tested approaches at the maximum analysed density of GNSS/levelling points (about 1point30km2). The differences between the modelling results became apparent only with an increase in the distance between the GNSS/levelling data points and the reduced accuracy of the used global geopotential model. Numéro de notice : A2020-027 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2018.1525981 date de publication en ligne : 10/10/2018 En ligne : https://doi.org/10.1080/00396265.2018.1525981 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94479 [article]

A global vertical datum defined by the conventional geoid potential and the Earth ellipsoid parameters / Hadi Amin in Journal of geodesy, vol 93 n°10 (October 2019)  

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Transformation 3D des coordonnées GPS en coordonnées Nord Sahara avec la MRE / Medjahed Sid Ahmed in Géomatique expert, n° 130-131 (octobre-novembre-décembre 2019)

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The Iranian height datum offset from the GBVP solution and spirit-leveling/gravimetry data / Amir Ebadi in Journal of geodesy, vol 93 n° 8 (August 2019)  

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Error propagation for the Molodensky G1 term / Jack C. McCubbine in Journal of geodesy, vol 93 n°6 (June 2019)  

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A generalized theory of the figure of the Earth : formulae / Chengli Huang in Journal of geodesy, vol 93 n° 3 (March 2019)  

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On the assimilation of absolute geodetic dynamic topography in a global ocean model: impact on the deep ocean state / Alexey Androsov in Journal of geodesy, vol 93 n° 2 (February 2019)  

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Enhancing the predictability of least-squares collocation through the integration with least-squares-support vector machine / Hossam Talaat Elshambaky in Journal of applied geodesy, vol 13 n° 1 (January 2019)  

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How IGN (France) computed the so-called "centre of gravity" of physical Europe in 1989 and 2004 / Jean-François Hangouët (2019)  

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AUSGeoid2020 combined gravimetric–geometric model : location-specific uncertainties and baseline-length-dependent error decorrelation / Nicholas J. Brown in Journal of geodesy, vol 92 n° 12 (December 2018)  

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La forme de la terre dans l'histoire occidentale / Xavier Della Chiesa in XYZ, n° 157 (décembre 2018 - février 2019)

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