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Gravitational field modelling near irregularly shaped bodies using spherical harmonics: a case study for the asteroid (101955) Bennu / Blažej Bucha in Journal of geodesy, vol 95 n° 5 (May 2021)  

Public [article]  inJournal of geodesy > vol 95 n° 5 (May 2021) . - n° 56 Titre : Gravitational field modelling near irregularly shaped bodies using spherical harmonics: a case study for the asteroid (101955) Bennu Type de document : Article/Communication Auteurs : Blažej Bucha, Auteur ; Fernando Sanso, Auteur Année de publication : 2021 Article en page(s) : n° 56 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] astéroïde [Termes IGN] champ de gravitation [Termes IGN] champ de pesanteur terrestre [Termes IGN] convergence [Termes IGN] harmonique sphérique [Termes IGN] intégrale de Newton Résumé : (auteur) We apply three spherical-harmonic-based techniques to deliver external gravitational field models of the asteroid (101955) Bennu within its circumscribing sphere. This region is known to be peculiar for external spherical harmonic expansions, because it may lead to a divergent series. The studied approaches are (i) spectral gravity forward modelling via external spherical harmonics, (ii) the least-squares estimation from surface gravitational data using external spherical harmonics and (iii) the combination of internal and external series expansions. While the first method diverges beyond any reasonable doubts, we show that the other two methods may ensure relative accuracy from ∼10−6 to 10−8 in the vicinity of Bennu. This is possible even with the second method, despite the fact that it relies on a single series of external spherical harmonics. Our main motivation was to study conceptual differences between spherical harmonic coefficients from satellite data (analogy to the first method) and from surface gravitational data (the second method). Such coefficients are available through the popular spherical-harmonic-based models of the Earth’s gravitational field and often are combined together. We show that the coefficients from terrestrial data may lead to a divergence effect of partial sums, though excellent accuracy can be achieved when such model is used in full. Under (presently) extreme but realistic conditions, the divergence effect of partial sums may affect many near-surface geoscientific applications, such as the geoid/quasigeoid computation or residual terrain modelling. Computer codes (Fortran, MATLAB) and data produced within the study are made freely available at http://edisk.cvt.stuba.sk/~xbuchab/. Numéro de notice : A2021-347 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-021-01493-w date de publication en ligne : 22/04/2021 En ligne : https://doi.org/10.1007/s00190-021-01493-w Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97591 [article]

Using real polar ground gravimetry data to solve the GOCE polar gap problem in satellite-only gravity field recovery / Biao Lu in Journal of geodesy, Vol 94 n°3 (March 2020)  

Public [article]  inJournal of geodesy > Vol 94 n°3 (March 2020) Titre : Using real polar ground gravimetry data to solve the GOCE polar gap problem in satellite-only gravity field recovery Type de document : Article/Communication Auteurs : Biao Lu, Auteur ; Christoph Förste, Auteur ; Franz Barthelmes, Auteur ; et al., Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] anomalie de pesanteur [Termes IGN] Antarctique [Termes IGN] Arctique [Termes IGN] champ de gravitation [Termes IGN] données GOCE [Termes IGN] données GRACE [Termes IGN] Earth Gravity Model 2008 [Termes IGN] filtrage d'information [Termes IGN] levé gravimétrique [Termes IGN] modèle de géopotentiel [Termes IGN] zone polaire Résumé : (auteur) With the successful completion of European Space Agency (ESA)’s PolarGAP campaign, ground gravity data are now available for both polar regions. Therefore, it is now possible to solve the GOCE polar gap problem in satellite-only gravity field recovery by using additional polar ground gravity data instead of some regularization methods. However, ground gravimetry data need to be filtered to remove the short-wavelength information beyond a certain harmonic degree to avoid spectral leakage when inferring satellite-only gravity field models. For the Arctic, the ArcGP data set was successfully applied when inferring the high-resolution gravity field model EGM2008 which could be used for this filtering there. For Antarctica, a combination of latest airborne gravimetry data from ESA’s PolarGap campaign and some previous gravity data was recently published which was irregularly distributed in space and still had some small gaps within the GOCE south polar gap. Therefore, we proposed a point mass modeling method for this filtering which was similar to the way using EGM2008 for such filtering to the ground gravity data in the Arctic. Furthermore, a variance component estimation was applied to combine the normal equations from the different sources to build a global gravity field model called IGGT_R1C. Then, this model’s accuracy was evaluated by comparison with other gravity field models in terms of difference degree amplitudes, gravity anomaly differences as well as external checking by obit adjustment and gravity data in the GOCE polar gap areas. This gravity field model performed well globally according to these checking results; especially, the RMS of the residuals between the filtered gravity data and that calculated from IGGT_R1C was the smallest (2.6 mGal in the Arctic and 5.4 mGal in Antarctica) compared with that of the relevant satellite-only gravity field models, e.g., GOCO05s. Therefore, the disturbing impact of the GOCE polar data gap problem could be solved by adding the polar ground gravity data. Numéro de notice : A2020-155 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01361-z date de publication en ligne : 25/02/2020 En ligne : https://doi.org/10.1007/s00190-020-01361-z Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94805 [article]

Gravity / Taher Zouaghi (2018)  

Public Titre : Gravity : Geoscience Applications, Industrial Technology and Quantum Aspect Type de document : Monographie Auteurs : Taher Zouaghi, Éditeur scientifique Editeur : London [UK] : IntechOpen Année de publication : 2018 Format : 19 x 27 cm ISBN/ISSN/EAN : 978-953-51-4059-7 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] centre de gravité [Termes IGN] champ de gravitation [Termes IGN] champ de pesanteur terrestre [Termes IGN] modèle de géopotentiel [Termes IGN] modèle géologique [Termes IGN] structure géologique [Termes IGN] transformation en ondelettes Résumé : (éditeur) This book deals with different aspects of gravity that has proved its effectiveness throughout the world, hence their solicitation in recent years. Fundamental theories, applications, and tools have been presented, emphasizing the implementation of the gravity technique. Different research themes for diverse areas in the world are detailed here, highlighting new methods of studies that could be helpful for sophisticated and modern development over the next few years. Four main sections are presented: Gravity Interpretation Tools in Geoscience, Gravity in Geoscience Applications, Gravity in Industrial Technology, and Quantum Gravity. Theoretical and acquisition tools and adapted processing methods have been designed to take into account the initial data, and modeling results thus converge toward a better solution. This book, which makes a worthwhile contribution to the topic gravity, is specifically addressed to specialists, researchers, and industry professionals who shall find its content extremely useful for a better comprehension of the geological, spatial, and industrial aspects of gravity. Note de contenu : 1- Gravity data interpretation using different new algorithms: A comparative study 2- 3D modeling and inversion of gravity data in exploration scale 3- Microgravity and its applications in geosciences 4- Application of BEMD in extraction of regional and local gravity anomalies reflecting geological structures associated with mineral resources 5- Identification of gravity lineaments for water resources in the crystalline Massif of Hoggar (South of Algeria) 6- Gravity application for delineating subsurface structures at different localities in Egypt 7- Gravity in heat pipe technology 8- Analysis of the influence of fish behavior on the hydrodynamics of net cage 9- Beyond Einstein: A polynomial affine model of gravity 10- Gravity, curvature and energy: gravitational field intentionality to the cohesion and union of the universe Numéro de notice : 28508 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Recueil / ouvrage collectif DOI : 10.5772/intechopen.68576 En ligne : https://doi.org/10.5772/intechopen.68576 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97043

Assessment 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)  

Public [article]  inJournal of geodesy > vol 90 n° 12 (December 2016) . - pp 1371 - 1388 Titre : Assessment 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 Type de document : Article/Communication Auteurs : Graham Appleby, Auteur ; José Rodríguez, Auteur ; Zuheir Altamimi , Auteur Année de publication : 2016 Article en page(s) : pp 1371 - 1388 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] analyse diachronique [Termes IGN] champ de gravitation [Termes IGN] constante [Termes IGN] données Lageos [Termes IGN] données TLS (télémétrie) [Termes IGN] erreur systématique [Termes IGN] géocentre [Termes IGN] système de référence géodésique Résumé : (Auteur) Satellite laser ranging (SLR) to the geodetic satellites LAGEOS and LAGEOS-2 uniquely determines the origin of the terrestrial reference frame and, jointly with very long baseline interferometry, its scale. Given such a fundamental role in satellite geodesy, it is crucial that any systematic errors in either technique are at an absolute minimum as efforts continue to realise the reference frame at millimetre levels of accuracy to meet the present and future science requirements. Here, we examine the intrinsic accuracy of SLR measurements made by tracking stations of the International Laser Ranging Service using normal point observations of the two LAGEOS satellites in the period 1993 to 2014. The approach we investigate in this paper is to compute weekly reference frame solutions solving for satellite initial state vectors, station coordinates and daily Earth orientation parameters, estimating along with these weekly average range errors for each and every one of the observing stations. Potential issues in any of the large number of SLR stations assumed to have been free of error in previous realisations of the ITRF may have been absorbed in the reference frame, primarily in station height. Likewise, systematic range errors estimated against a fixed frame that may itself suffer from accuracy issues will absorb network-wide problems into station-specific results. Our results suggest that in the past two decades, the scale of the ITRF derived from the SLR technique has been close to 0.7 ppb too small, due to systematic errors either or both in the range measurements and their treatment. We discuss these results in the context of preparations for ITRF2014 and additionally consider the impact of this work on the currently adopted value of the geocentric gravitational constant, GM. Numéro de notice : A2016-808 Affiliation des auteurs : LaSTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0929-2 date de publication en ligne : 29/06/2016 En ligne : http://dx.doi.org/10.1007/s00190-016-0929-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82596 [article]

Drift mode accelerometry for spaceborne gravity measurements / John W. Conklin in Journal of geodesy, vol 89 n° 11 (november 2015)  

Public [article]  inJournal of geodesy > vol 89 n° 11 (november 2015) . - pp 1053 - 1070 Titre : Drift mode accelerometry for spaceborne gravity measurements Type de document : Article/Communication Auteurs : John W. Conklin, Auteur Année de publication : 2015 Article en page(s) : pp 1053 - 1070 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] accéléromètre [Termes IGN] capteur spatial [Termes IGN] champ de gravitation [Termes IGN] test de performance [Termes IGN] torsion géodésique Résumé : (auteur) A drift mode accelerometer is a precision instrument for spacecraft that overcomes much of the acceleration noise and readout dynamic range limitations of traditional electrostatic accelerometers. It has the potential of achieving acceleration noise performance similar to that of drag-free systems over a restricted frequency band without the need for external drag-free control or continuous spacecraft propulsion. Like traditional accelerometers, the drift mode accelerometer contains a high-density test mass surrounded by an electrode housing, which can control and sense all six degrees of freedom of the test mass. Unlike traditional accelerometers, the suspension system is operated with a low duty cycle so that the limiting suspension force noise only acts over brief, known time intervals, which can be neglected in the data analysis. The readout is performed using a laser interferometer which is immune to the dynamic range limitations of even the best voltage references typically used to determine the inertial acceleration of electrostatic accelerometers. The drift mode accelerometer is a novel offshoot of the like-named operational mode of the LISA Pathfinder spacecraft, in which its test mass suspension system is cycled on and off to estimate the acceleration noise associated with the front-end electronics. This paper presents the concept of a drift mode accelerometer, describes the operation of such a device, develops models for its performance with respect to non-drag-free satellite geodesy and gravitational wave missions, and discusses plans for testing the performance of a prototype sensor in the laboratory using torsion pendula. Numéro de notice : A2015-882 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0833-1 date de publication en ligne : 02/07/2015 En ligne : https://doi.org/10.1007/s00190-015-0833-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79421 [article]

Alternative validation method of satellite gradiometric data by integral transform of satellite altimetry data / Michal Šprlák in Journal of geodesy, vol 89 n° 8 (August 2015)  

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Empirical model of the gravitational field generated by the oceanic lithosphere / Robert Tenzer in Advances in space research, vol 55 n° 1 ([01/01/2015])  

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Geodesy / Wolfgang Torge (2012)

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Comparaison de deux stratégies de calcul de géoïde / H. Chaira (2003)

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Inverse Probleme bei der Gravitationsfelsbestimmung mittels SST- und SGG-Satellitenmissionen Darstellungen / J. Kusche (2002)

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Space gravity spectroscopy - The sensitivity analysis of GPS-tracked satellite missions (case study CHAMP) / C. Schäfer (2001)

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Regionale und globale Gravitationsfeldanalyse hochauflösender Satellitendaten mittels Mehrgitterverfahren / S. Rudolph (2000)

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The IERS terrestrial reference system / Zuheir Altamimi (1993)

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Relativistic motion of gyroscopes and space gradiometry / E. Gill (1992)

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Das Projekt "Satelliten- und Inertialgeodäsie" der Bayerischen Kommission für die Internationale Erdmessung Berichtskolloquium anläßlich der Begutachtung der Kommission im Rahmen des Akademienprogramms am 2. und 3. Juli 1990 / Rudolf Sigl (1991)

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