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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)
[article]
Titre : A global vertical datum defined by the conventional geoid potential and the Earth ellipsoid parameters Type de document : Article/Communication Auteurs : Hadi Amin, Auteur ; Lard Erik Sjöberg, Auteur ; Mohammad Bagherbandi, Auteur Année de publication : 2019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] coordonnées cartésiennes géocentriques
[Termes IGN] ellipsoïde de référence
[Termes IGN] géoïde
[Termes IGN] géoïde gravimétrique
[Termes IGN] harmonique ellipsoïdale
[Termes IGN] modèle de géopotentiel
[Termes IGN] surface de la mer
[Termes IGN] système de référence altimétrique
[Termes IGN] système de référence géodésiqueRésumé : (auteur) The geoid, according to the classical Gauss–Listing definition, is, among infinite equipotential surfaces of the Earth’s gravity field, the equipotential surface that in a least squares sense best fits the undisturbed mean sea level. This equipotential surface, except for its zero-degree harmonic, can be characterized using the Earth’s global gravity models (GGM). Although, nowadays, satellite altimetry technique provides the absolute geoid height over oceans that can be used to calibrate the unknown zero-degree harmonic of the gravimetric geoid models, this technique cannot be utilized to estimate the geometric parameters of the mean Earth ellipsoid (MEE). The main objective of this study is to perform a joint estimation of W0, which defines the zero datum of vertical coordinates, and the MEE parameters relying on a new approach and on the newest gravity field, mean sea surface and mean dynamic topography models. As our approach utilizes both satellite altimetry observations and a GGM model, we consider different aspects of the input data to evaluate the sensitivity of our estimations to the input data. Unlike previous studies, our results show that it is not sufficient to use only the satellite-component of a quasi-stationary GGM to estimate W0. In addition, our results confirm a high sensitivity of the applied approach to the altimetry-based geoid heights, i.e., mean sea surface and mean dynamic topography models. Moreover, as W0 should be considered a quasi-stationary parameter, we quantify the effect of time-dependent Earth’s gravity field changes as well as the time-dependent sea level changes on the estimation of W0. Our computations resulted in the geoid potential W0 = 62636848.102 ± 0.004 m2 s−2 and the semi-major and minor axes of the MEE, a = 6378137.678 ± 0.0003 m and b = 6356752.964 ± 0.0005 m, which are 0.678 and 0.650 m larger than those axes of GRS80 reference ellipsoid, respectively. Moreover, a new estimation for the geocentric gravitational constant was obtained as GM = (398600460.55 ± 0.03) × 106 m3 s−2. Numéro de notice : A2019-608 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-019-01293-3 Date de publication en ligne : 12/09/2019 En ligne : https://doi.org/10.1007/s00190-019-01293-3 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94791
in Journal of geodesy > vol 93 n°10 (October 2019)[article]Combination of GRACE monthly gravity fields on the normal equation level / Ulrich Meyer in Journal of geodesy, vol 93 n° 9 (September 2019)
[article]
Titre : Combination of GRACE monthly gravity fields on the normal equation level Type de document : Article/Communication Auteurs : Ulrich Meyer, Auteur ; Yoomin Jean, Auteur ; A. Kvas, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : pp 1645 - 1658 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse de variance
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] données GRACE
[Termes IGN] filtrage du bruit
[Termes IGN] gravimétrie spatiale
[Termes IGN] mesure de la qualité
[Termes IGN] série temporelleRésumé : (Auteur) A large number of time-series of monthly gravity fields derived from GRACE data provide users with a wealth of information on mass transport processes in the system Earth. The users are, however, left alone with the decision which time-series to analyze. Following the example of other well-known combination services provided by the geodetic community, the prototype of a combination service has been developed within the frame of the project EGSIEM (2015–2017) to combine the different time-series with the goal to provide a unique and superior product to the user community. Four associated analysis centers (ACs) of EGSIEM, namely AIUB, GFZ, GRGS and IfG, generated monthly gravity fields which were then combined using the different normal equations (NEQs). But the relative weights determined by variance component estimation (VCE) on the NEQ level do not lead to an optimal combined product due to the different processing strategies applied by the individual ACs. We therefore resort to VCE on the solution level to derive relative weights that are representative of the noise levels of the individual solutions. These weights are then applied in the combination on the NEQ level. Prior to combination, empirical scaling factors that are based on pairwise combinations of NEQs are derived to balance the impact of the NEQs on the combined solution. We compare the processing approaches of the different ACs and introduce quality measures derived either from the differences w.r.t. the monthly means of the individual gravity fields or w.r.t. a deterministic signal model. After combination, the gravity fields are validated by comparison to the official GRACE SDS RL05 time-series and the individual contributions of the associated ACs in the spectral and the spatial domain. While the combined gravity fields are comparable in signal strength to the individual time-series, they stand out by their low noise level. In terms of noise, they are in 90% of all months as good or better than the best individual contribution from IfG and significantly less noisy than the official GRACE SDS RL05 time-series. Numéro de notice : A2019-507 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-019-01274-6 Date de publication en ligne : 02/07/2019 En ligne : https://doi.org/10.1007/s00190-019-01274-6 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93792
in Journal of geodesy > vol 93 n° 9 (September 2019) . - pp 1645 - 1658[article]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)
[article]
Titre : The Iranian height datum offset from the GBVP solution and spirit-leveling/gravimetry data Type de document : Article/Communication Auteurs : Amir Ebadi, Auteur ; Alireza A. Ardalan, Auteur ; Roohollah Karimi, Auteur Année de publication : 2019 Article en page(s) : pp 1207 - 1225 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse de variance
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] compensation par moindres carrés
[Termes IGN] géoïde terrestre
[Termes IGN] Iran
[Termes IGN] levé gravimétrique
[Termes IGN] modèle de géopotentiel
[Termes IGN] potentiel de pesanteur terrestre
[Termes IGN] problème des valeurs limites
[Termes IGN] réseau altimétrique local
[Termes IGN] réseau altimétrique nationalRésumé : (auteur) The gravity potential of the zero point of the Iranian height datum (IRHD) is determined as well as the IRHD offset from a global geoid. For this purpose, the geodetic boundary value problem (GBVP) solution based on the remove–compute–restore (RCR) technique is used. In the RCR technique, a global geopotential model (GGM) is required as a reference to remove and restore the long wavelengths of the gravity field. Since the GGMs do not have adequate accuracy over Iran, the IRHD offset is not precisely estimated by the GBVP solution. In this study, aiming to improve the latter, a combination solution based on the GBVP approach and spirit-leveling/gravimetry (LG) data, called the GBVP_LG solution, is proposed. To obtain the GBVP_LG solution, gravity potential obtained from the GBVP solution and the gravity potential differences derived from the LG data are used as two types of observations in a least-squares adjustment. The proper relative weight matrices are determined using the variance component estimation method. To evaluate the proposed method, the gravity potential differences between the start and end points of several check-lines in the leveling network derived from the GBVP and GBVP_LG solutions are compared with those of the LG data. The results show that the dependency of the GBVP_LG solution on the reference model used is much less than that of the GBVP solution. In addition, the results indicate that the GBVP_LG solution has a 42% improvement with respect to the GBVP solution in terms of root-mean-square error. As a result of the GBVP_LG solution, the gravity potential of the IRHD zero point is estimated equal to WIRHD0=62,636,855.89±0.16m2/s2. Therefore, the IRHD offset with respect to the geoid defined by W0=62,636,853.4m2/s2 is obtained equal to −25.4±1.6cm, which means that the IRHD is 25.4 cm below the geoid. Numéro de notice : A2019-385 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-019-01237-x Date de publication en ligne : 12/02/2019 En ligne : https://doi.org/10.1007/s00190-019-01237-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93464
in Journal of geodesy > vol 93 n° 8 (August 2019) . - pp 1207 - 1225[article]Deflections of the vertical from full-tensor and single-instrument gravity gradiometry / Christopher Jekeli in Journal of geodesy, vol 93 n° 3 (March 2019)
[article]
Titre : Deflections of the vertical from full-tensor and single-instrument gravity gradiometry Type de document : Article/Communication Auteurs : Christopher Jekeli, Auteur Année de publication : 2019 Article en page(s) : pp 369 - 382 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] déviation de la verticale
[Termes IGN] faille géologique
[Termes IGN] gradient de gravitation
[Termes IGN] intégration de données
[Termes IGN] levé gravimétriqueRésumé : (Auteur) Gravity gradiometry on a moving platform, whether ground or airborne, has the potential to offer an efficient and accurate determination of the deflection of the vertical by simple line integration. A significant error in this process is a trend error that results from the integration of systematic gradient errors. Using an airborne full-tensor gradiometry data set of regularly spaced and intersecting tracks over a 10 km square region and the USDOV2012 vertical deflection model to calibrate these long wavelength errors, it is shown that the gradient-derived deflections agree with the USDOV2012 model at the level of 0.6–0.9 arcsec. Moreover, it is shown by graphical inspection that these differences represent high-frequency signal rather than error. Another data processing technique is examined using only (simulated) single-gradiometer instrument data, i.e., the local differential curvature components, (Γyy−Γxx)/2 and Γxy, of the gravity field. While in theory these data can yield deflection components using two parallel data tracks, the results in the tested case are unsatisfactory due to implicit additional cross-track integration errors that accumulate systematically. The analysis thus demonstrates the importance of using the individual horizontal gradient components, Γxx, Γyy, to derive the deflection of the vertical. Numéro de notice : A2019-152 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1162-y Date de publication en ligne : 11/07/2018 En ligne : https://doi.org/10.1007/s00190-018-1162-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92491
in Journal of geodesy > vol 93 n° 3 (March 2019) . - pp 369 - 382[article]Correlated atom accelerometers for mapping the Earth gravity field from space / Thomas Lévèque (2019)
Titre : Correlated atom accelerometers for mapping the Earth gravity field from space Type de document : Article/Communication Auteurs : Thomas Lévèque, Auteur ; C. Fallet, Auteur ; Mioara Mandea, Auteur ; Richard Biancale, Auteur ; Jean-Michel Lemoine, Auteur ; Simon Tardivel, Auteur ; Marc Delpech, Auteur ; Guillaume Ramillien, Auteur ; Isabelle Panet , Auteur ; S. Bourgogne, Auteur ; Franck Pereira dos Santos, Auteur ; Ph. Bouyer, Auteur Editeur : Washington : Society of Photo-Optical Instrumentation Engineers SPIE Année de publication : 2019 Collection : SPIE Proceedings num. 11180 Projets : 1-Pas de projet / Conférence : ICSO 2018, International Conference on Space Optics 09/10/2018 12/10/2018 Chania Grèce Proceedings SPIE Importance : 9 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] accélération
[Termes IGN] accéléromètre
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] mission spatialeRésumé : (auteur) The emergence of quantum technologies, including cold atom based accelerometers, offers an opportunity to improve the performances of space geodesy missions. In this context, CNES initiated an assessment study called GRICE (GRadiométrie à Interféromètres quantiques Corrélés pour l’Espace) in order to evaluate the impact of cold atom technologies to space geodesy and to the end users of the geodetic data. In this paper, we present a specific mission scenario for gravity field mapping based on a twin satellite concept. The mission uses a constellation of two satellites each equipped with a cold atom accelerometer. A laser link measures the distance between the two satellites and couples these two instruments in order to produce a correlated differential acceleration measurement. The main parameters, determining the performances of the payload, have been investigated. In addition, a preliminary study of mass, consumption and volume has been conducted to ensure the onboard feasibility of these instruments. A general study of the satellite architecture, including all the subsystems, has also been realized and is presented here. Numéro de notice : C2018-126 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1117/12.2535951 En ligne : https://doi.org/10.1117/12.2535951 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100045 Evaluation of terrestrial and airborne gravity data over Antarctica : a generic approach / Philipp Zingerle in Journal of geodetic science, vol 9 n° 1 (January 2019)PermalinkMass variation observing system by high low inter-satellite links (MOBILE) : a new concept for sustained observation of mass transport from space / Roland Pail in Journal of geodetic science, vol 9 n° 1 (January 2019)PermalinkReconciling upper mantle seismic velocity and density structure below ocean basins / Isabelle Panet (2019)PermalinkPermalinkAn analysis of gravitational gradients in rotated frames and their relation to oriented mass sources / Isabelle Panet in Journal of geophysical research : Solid Earth, vol 123 n° 12 (December 2018)PermalinkA Terrestrial Reference Frame realised on the observation level using a GPS-LEO satellite constellation / Daniel Koenig in Journal of geodesy, vol 92 n° 11 (November 2018)PermalinkLeast-squares cross-wavelet analysis and its applications in geophysical time series / Ebrahim Ghaderpour in Journal of geodesy, vol 92 n° 10 (October 2018)PermalinkMigrating pattern of deformation prior to the Tohoku-Oki earthquake revealed by GRACE data / Isabelle Panet in Nature geoscience, vol 11 n° 5 (May 2018)PermalinkHigh performance clocks and gravity field determination / Jurgen Müller in Space Science Reviews, vol 214 n° 1 (February 2018)PermalinkDétermination d’un modèle géopotentiel à haute résolution en zone littorale aidé par des mesures d’horloges atomiques / Hugo Lecomte (2018)PermalinkPermalinkMulti-scale modeling of Earth's gravity field in space and time / Shuo (2) Wang in Journal of geodynamics, vol 106 (May 2017)PermalinkPermalinkEléments de géodésie et de la théorie des moindres carrés / Abdelmajid Ben Hadj Salem (2017)PermalinkLa gravimétrie mobile en champ proche : outil essentiel pour la haute résolution en géodésie physique et en géosciences / Jérome Verdun (2017)PermalinkPermalinkAssessment of the accuracy of global geodetic satellite laser ranging observations and estimated impact on ITRF scale: estimation of systematic errors in LAGEOS observations 1993–2014 / Graham Appleby in Journal of geodesy, vol 90 n° 12 (December 2016)PermalinkEffects of space weather on GOCE electrostatic gravity gradiometer measurements / Elmas Sinem Ince in Journal of geodesy, vol 90 n° 12 (December 2016)PermalinkOn the spectral combination of satellite gravity model, terrestrial and airborne gravity data for local gravimetric geoid computation / Tao Jian in Journal of geodesy, vol 90 n° 12 (December 2016)PermalinkOn the usefulness of relativistic space-times for the description of the Earth’s gravitational field / Michael Soffel in Journal of geodesy, vol 90 n° 12 (December 2016)Permalink