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Astronomical-topographic levelling using high-precision astrogeodetic vertical deflections and Digital Terrain Model data / C. Hirt in Journal of geodesy, vol 82 n° 4-5 (April - May 2008)
[article]
Titre : Astronomical-topographic levelling using high-precision astrogeodetic vertical deflections and Digital Terrain Model data Type de document : Article/Communication Auteurs : C. Hirt, Auteur ; J. Flury, Auteur Année de publication : 2008 Article en page(s) : pp 231 - 248 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Nivellement
[Termes IGN] Alpes
[Termes IGN] champ de pesanteur local
[Termes IGN] collocation par moindres carrés
[Termes IGN] déviation de la verticale
[Termes IGN] modèle numérique de terrain
[Termes IGN] nivellement indirectRésumé : (Auteur) At the beginning of the twenty-first century, a technological change took place in geodetic astronomy by the development of Digital Zenith Camera Systems (DZCS). Such instruments provide vertical deflection data at an angular accuracy level of 0.?1 and better. Recently, DZCS have been employed for the collection of dense sets of astrogeodetic vertical deflection data in several test areas in Germany with high-resolution digital terrain model (DTM) data (10–50 m resolution) available. These considerable advancements motivate a new analysis of the method of astronomical-topographic levelling, which uses DTM data for the interpolation between the astrogeodetic stations. We present and analyse a least-squares collocation technique that uses DTM data for the accurate interpolation of vertical deflection data. The combination of both data sets allows a precise determination of the gravity field along profiles, even in regions with a rugged topography. The accuracy of the method is studied with particular attention on the density of astrogeodetic stations. The error propagation rule of astronomical levelling is empirically derived. It accounts for the signal omission that increases with the station spacing. In a test area located in the German Alps, the method was successfully applied to the determination of a quasigeoid profile of 23 km length. For a station spacing from a few 100 m to about 2 km, the accuracy of the quasigeoid was found to be about 1–2 mm, which corresponds to a relative accuracy of about 0.05-0.1 ppm. Application examples are given, such as the local and regional validation of gravity field models computed from gravimetric data and the economic gravity field determination in geodetically less covered regions. Copyright Springer Numéro de notice : A2008-168 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0173-x En ligne : https://doi.org/10.1007/s00190-007-0173-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29163
in Journal of geodesy > vol 82 n° 4-5 (April - May 2008) . - pp 231 - 248[article]Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-08042 RAB Revue Centre de documentation En réserve L003 Disponible 266-08041 RAB Revue Centre de documentation En réserve L003 Disponible Length-of-day and space-geodetic determination of the Earth's variable gravity field / G. Bourda in Journal of geodesy, vol 82 n° 4-5 (April - May 2008)
[article]
Titre : Length-of-day and space-geodetic determination of the Earth's variable gravity field Type de document : Article/Communication Auteurs : G. Bourda, Auteur Année de publication : 2008 Article en page(s) : pp 295 - 305 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse comparative
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] données GRACE
[Termes IGN] données TLS (télémétrie)
[Termes IGN] GRACE
[Termes IGN] télémétrie laser sur satellite
[Termes IGN] variationRésumé : (Auteur) The temporal variations of the Earth’s gravity field, nowadays routinely determined from satellite laser ranging (SLR) and GRACE (Gravity Recovery And Climate Experiment), are related to changes in the Earth’s rotation rate through the Earth’s inertia tensor. We study this connection from actual data by comparing the traditional length-of-day (LOD) measurements provided by the International Earth Rotation and Reference Systems Service (IERS) to the variations of the degree-2 and order-0 Stokes coefficient of the gravity field determined from fitting the orbits of the LAGEOS-1 and -2 satellites since 1985. The two series show a good correlation (0.62) and similar annual and semi-annual signals, indicating that the gravity-field-derived LOD is valuable. Our analysis also provides evidence for additional signals common to both series, especially at a period near 120 days, which could be due to hydrological effects. Copyright Springer Numéro de notice : A2008-171 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0180-y En ligne : https://doi.org/10.1007/s00190-007-0180-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29166
in Journal of geodesy > vol 82 n° 4-5 (April - May 2008) . - pp 295 - 305[article]Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-08042 RAB Revue Centre de documentation En réserve L003 Disponible 266-08041 RAB Revue Centre de documentation En réserve L003 Disponible On the non-uniqueness of local quasi-geoids computed from terrestrial gravity anomalies / I. Prutkin in Journal of geodesy, vol 82 n° 3 (March 2008)
[article]
Titre : On the non-uniqueness of local quasi-geoids computed from terrestrial gravity anomalies Type de document : Article/Communication Auteurs : I. Prutkin, Auteur ; R. Klees, Auteur Année de publication : 2008 Article en page(s) : pp 147 - 156 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] anomalie de pesanteur
[Termes IGN] champ de pesanteur local
[Termes IGN] données GPS
[Termes IGN] géoïde local
[Termes IGN] nivellement par GPSRésumé : (Auteur) We consider the problem of local (quasi-)geoid modelling from terrestrial gravity anomalies. Whereas this problem is uniquely solvable (up to spherical harmonic degree one) if gravity anomalies are globally available, the problem is non-unique if gravity anomalies are only available within a local area, which is the typical situation in local/regional gravity field modelling. We derive a mathematical description of the kernel of the gravity anomaly operator. The non-uniqueness can be removed using external height anomaly information, e.g., provided by GPS-levelling. The corresponding problem is formulated as a Cauchy problem for the Laplace equation. The existence and uniqueness of the solution of the Cauchy problem is guaranteed by the Cauchy–Kowalevskaya theorem. We propose several numerical procedures to compute the solution of the Cauchy problem from given differences between gravimetric and geometric height anomalies. We apply the numerical techniques to real data over the Netherlands and Germany. We show that we can compute a unique quasi-geoid from observed gravimetric and geometric height anomalies, which agree with the data within the expected noise level. We conclude that observed differences between gravimetric height anomalies and geometric height anomalies derived from GPS and levelling cannot only be attributed to systematic errors in the data sets, but are also caused by the intrinsic non-uniqueness of the problem of local quasi-geoid modelling from gravity anomalies. Hence, GPS-levelling data are necessary to get a unique solution, which also implies that they should not be used to validate local quasi-geoid solutions computed on the basis of gravity anomalies. Copyright Springer Numéro de notice : A2008-166 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0161-1 En ligne : https://doi.org/10.1007/s00190-007-0161-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29161
in Journal of geodesy > vol 82 n° 3 (March 2008) . - pp 147 - 156[article]Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-08031 RAB Revue Centre de documentation En réserve L003 Disponible 266-08032 RAB Revue Centre de documentation En réserve L003 Disponible Effects of topographic-isostatic masses on gravitational functionals at the Earth's surface and at airborne and satellite altitudes / A. Makhloof in Journal of geodesy, vol 82 n° 2 (February 2008)
[article]
Titre : Effects of topographic-isostatic masses on gravitational functionals at the Earth's surface and at airborne and satellite altitudes Type de document : Article/Communication Auteurs : A. Makhloof, Auteur ; K.H. Ilk, Auteur Année de publication : 2008 Article en page(s) : pp 93 - 111 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur local
[Termes IGN] force de gravitation
[Termes IGN] gravimétrie aérienne
[Termes IGN] gravimétrie spatiale
[Termes IGN] isostasie
[Termes IGN] pesanteur terrestre
[Termes IGN] reliefRésumé : (Auteur) Topographic–isostatic masses represent an important source of gravity field information, especially in the high-frequency band, even if the detailed mass-density distribution inside the topographic masses is unknown. If this information is used within a remove-restore procedure, then the instability problems in downward continuation of gravity observations from aircraft or satellite altitudes can be reduced. In this article, integral formulae are derived for determination of gravitational effects of topographic–isostatic masses on the first- and second-order derivatives of the gravitational potential for three topographic–isostatic models. The application of these formulas is useful for airborne gravimetry/gradiometry and satellite gravity gradiometry. The formulas are presented in spherical approximation by separating the 3D integration in an analytical integration in the radial direction and 2D integration over the mean sphere. Therefore, spherical volume elements can be considered as being approximated by mass-lines located at the centre of the discretization compartments (the mass of the tesseroid is condensed mathematically along its vertical axis). The errors of this approximation are investigated for the second-order derivatives of the topographic–isostatic gravitational potential in the vicinity of the Earth’s surface. The formulas are then applied to various scenarios of airborne gravimetry/gradiometry and satellite gradiometry. The components of the gravitational vector at aircraft altitudes of 4 and 10 km have been determined, as well as the gravitational tensor components at a satellite altitude of 250 km envisaged for the forthcoming GOCE (gravity field and steady-state ocean-circulation explorer) mission. The numerical computations are based on digital elevation models with a 5-arc-minute resolution for satellite gravity gradiometry and 1-arc-minute resolution for airborne gravity/gradiometry. Copyright Springer Numéro de notice : A2008-044 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0159-8 En ligne : https://doi.org/10.1007/s00190-007-0159-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29039
in Journal of geodesy > vol 82 n° 2 (February 2008) . - pp 93 - 111[article]Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-08022 RAB Revue Centre de documentation En réserve L003 Disponible 266-08021 RAB Revue Centre de documentation En réserve L003 Disponible GOCE's measurements of the gravity field and beyond / R. Floberghaben in ESA bulletin, n° 133 (February 2008)
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Titre : GOCE's measurements of the gravity field and beyond Type de document : Article/Communication Auteurs : R. Floberghaben, Auteur ; M. Drinkwater, Auteur ; Roger Haagmans, Auteur ; M. Kern, Auteur Année de publication : 2008 Article en page(s) : pp 24 - 31 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] circulation océanique
[Termes IGN] GOCE
[Termes IGN] gradient de gravitation
[Termes IGN] levé gravimétrique
[Termes IGN] niveau moyen des mersRésumé : (Auteur) Ocean circulation, sea level rise and the ocean's role as a regulator of climate are just some of the critical phenomena that can be further studied with the help of GOCE's gravity field products. But how do the spacecraft's measurements become part of this new information source? Copyright European Space Agency Numéro de notice : A2008-125 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : http://www.esa.int/esapub/bulletin/bulletin133/bul133d_floberghagen.pdf Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29120
in ESA bulletin > n° 133 (February 2008) . - pp 24 - 31[article]Generation of study of high-resolution satellite gravity over the Sumatra earthquake region / Samprit Chatterjee in International Journal of Remote Sensing IJRS, vol 28 n° 13-14 (July 2007)PermalinkPractical geodesy: part 3 The geoid / Huibert-Jan Lekkerkerk in Geoinformatics, vol 10 n° 4 (01/06/2007)PermalinkThe topographic bias by analytical continuation in physical geodesy / Lard Erik Sjöberg in Journal of geodesy, vol 81 n° 5 (May 2007)PermalinkAirborne LaCoste & Romberg gravimetry: a space domain approach / M. Abbasi in Journal of geodesy, vol 81 n° 4 (April 2007)PermalinkDetermination of the free core nutation period from tidal gravity observations of the GGP superconducting gravimeter network / B. Ducarme in Journal of geodesy, vol 81 n° 3 (March 2007)PermalinkThe geopotential value W 0 for specifying the relativistic atomic time scale and a global vertical reference system / M. Bursa in Journal of geodesy, vol 81 n° 2 (February 2007)PermalinkEtude des ondelettes multipôles de Poisson / Lâmân Lelégard (2007)PermalinkLocal solutions to inverse problems in geodesy: The impact of the noise covariance structure upon the accuracy of estimation / F. Bauer in Journal of geodesy, vol 81 n° 1 (January 2007)PermalinkPermalinkNational report of the Federal Republic of Germany on the geodetic activities in the years 2003-2007, XXIV [24th] general assembly of the International Union for Geodesy and Geophysics (IUGG) 2007 in Perugia, Italy / J. Muller (2007)Permalink