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The topographic bias by analytical continuation in physical geodesy / Lard Erik Sjöberg in Journal of geodesy, vol 81 n° 5 (May 2007)
[article]
Titre : The topographic bias by analytical continuation in physical geodesy Type de document : Article/Communication Auteurs : Lard Erik Sjöberg, Auteur Année de publication : 2007 Article en page(s) : pp 345 - 350 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] erreur systématique
[Termes IGN] formule de Stokes
[Termes IGN] géoïde terrestre
[Termes IGN] potentiel de pesanteur terrestreRésumé : (Auteur) This study emphasizes that the harmonic downward continuation of an external representation of the Earth’s gravity potential to sea level through the topographic masses implies a topographic bias. It is shown that the bias is only dependent on the topographic density along the geocentric radius at the computation point. The bias corresponds to the combined topographic geoid effect, i.e., the sum of the direct and indirect topographic effects. For a laterally variable topographic density function, the combined geoid effect is proportional to terms of powers two and three of the topographic height, while all higher order terms vanish. The result is useful in geoid determination by analytical continuation, e.g., from an Earth gravity model, Stokes’s formula or a combination thereof. Copyright Springer Numéro de notice : A2007-123 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-006-0112-2 En ligne : https://doi.org/10.1007/s00190-006-0112-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28486
in Journal of geodesy > vol 81 n° 5 (May 2007) . - pp 345 - 350[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-07051 RAB Revue Centre de documentation En réserve L003 Disponible 266-07052 RAB Revue Centre de documentation En réserve L003 Disponible Airborne LaCoste & Romberg gravimetry: a space domain approach / M. Abbasi in Journal of geodesy, vol 81 n° 4 (April 2007)
[article]
Titre : Airborne LaCoste & Romberg gravimetry: a space domain approach Type de document : Article/Communication Auteurs : M. Abbasi, Auteur ; Jean-Pierre Barriot, Auteur ; Jérome Verdun , Auteur Année de publication : 2007 Article en page(s) : pp 269 - 283 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] équation différentielle
[Termes IGN] équation intégrale
[Termes IGN] filtre passe-bas
[Termes IGN] gravimétrie aérienne
[Termes IGN] levé gravimétrique
[Termes IGN] matrice de covariance
[Termes IGN] méthode des moindres carrés
[Termes IGN] modèle de géopotentielRésumé : (Auteur) This paper introduces a new approach to reduce the airborne gravity data acquired by a LaCoste & Romberg (L&R) air/sea gravimeter, or other similar gravimeters. The acceleration exerted on the gravimeter is the sum of gravity and the vertical and Eötvös accelerations of the aircraft. The L&R gravimeter outputs are: (1) the beam position, (2) the spring tension and (3) the cross coupling. Vertical and Eötvös accelerations are computed from GPS-derived aircraft positions. However, the vertical perturbing acceleration sensed by the gravimeter is not the same as the one sensed by the aircraft (via GPS). A determination of the aircraft-to-sensor transfer function is necessary. The second-order differential equation of the motion of the gravimeter’s beam mixes all the input and output parameters of the gravimeter. Conventionally, low-pass filtering in the frequency domain is used to extract the gravity signal, the filter being applied to each flight-line individually. By transforming the differential equation into an integral equation and by introducing related covariance matrices, we develop a new filtering method based on a least-squares approach that is able to take into account, in one stage, the data corresponding to all flight-lines. The a posteriori covariance matrix of the estimated gravity signal is an internal criterion of the precision of the method. As an example, we estimate the gravity values along the flight-lines from an airborne gravity survey over the Alps and introduce an a priori covariance matrix of the gravity disturbances from a global geopotential model. This matrix is used to regularize the ill-posed Fredholm integral equation introduced in this paper. Copyright Springer Numéro de notice : A2007-187 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-006-0107-z En ligne : https://doi.org/10.1007/s00190-006-0107-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28550
in Journal of geodesy > vol 81 n° 4 (April 2007) . - pp 269 - 283[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-07041 RAB Revue Centre de documentation En réserve L003 Disponible 266-07042 RAB Revue Centre de documentation En réserve L003 Disponible Practical geodesy : Part 2 The ellipsoid / Huibert-Jan Lekkerkerk in Geoinformatics, vol 10 n° 3 (01/04/2007)
[article]
Titre : Practical geodesy : Part 2 The ellipsoid Type de document : Article/Communication Auteurs : Huibert-Jan Lekkerkerk, Auteur Année de publication : 2007 Article en page(s) : pp 58 - 59 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] ellipsoïde de référence
[Termes IGN] European Terrestrial Reference System 1989
[Termes IGN] North American Datum 1983
[Termes IGN] World Geodetic System 1984Résumé : (Auteur) In the previous article, it was stated that the earth could be approximated by a sphere or ellipsoid. The sphere is often used for simple navigation calculations, but for more accurate positioning the ellipsoidal shape of the earth has to be taken into account. Copyright GeoInformatics Numéro de notice : A2007-198 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28561
in Geoinformatics > vol 10 n° 3 (01/04/2007) . - pp 58 - 59[article]Determination 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)
[article]
Titre : Determination of the free core nutation period from tidal gravity observations of the GGP superconducting gravimeter network Type de document : Article/Communication Auteurs : B. Ducarme, Auteur ; H.P. Sun, Auteur ; J.Q. Xu, Auteur Année de publication : 2007 Article en page(s) : pp 179 - 187 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] gravimètre supraconducteur
[Termes IGN] levé gravimétrique
[Termes IGN] marée océanique
[Termes IGN] pesanteur terrestre
[Termes IGN] réseau gravimétrique
[Termes IGN] surcharge océaniqueRésumé : (Auteur) This study is based on 25 long time-series of tidal gravity observations recorded with superconducting gravimeters at 20 stations belonging to the Global Geodynamic Project (GGP). We investigate the diurnal waves around the liquid core resonance, i.e., K 1, ?1 and ?1, to determine the free core nutation (FCN) period, and compare these experimental results with models of the Earth response to the tidal forces. For this purpose, it is necessary to compute corrected amplitude factors and phase differences by subtracting the ocean tide loading (OTL) effect. To determine this loading effect for each wave, it was thus necessary to interpolate the contribution of the smaller oceanic constituents from the four well determined diurnal waves, i.e., Q 1, O 1, P 1, K 1. It was done for 11 different ocean tide models: SCW80, CSR3.0, CSR4.0, FES95.2, FES99, FES02, TPXO2, ORI96, AG95, NAO99 and GOT00. The numerical results show that no model is decisively better than the others and that a mean tidal loading vector gives the most stable solution for a study of the liquid core resonance. We compared solutions based on the mean of the 11 ocean models to subsets of six models used in a previous study and five more recent ones. The calibration errors put a limit on the accuracy of our global results at the level of 1 0.1%, although the tidal factors of O 1 and K 1 are determined with an internal precision of close to 0.05%. The results for O 1 more closely fit the DDW99 non-hydrostatic anelastic model than the elastic one. However, the observed tidal factors of K 1 and ?1 correspond to a shift of the observed resonance with respect to this model. The MAT01 model better fits this resonance shape. From our tidal gravity data set, we computed the FCN eigenperiod. Our best estimation is 429.7 sidereal days (SD), with a 95% confidence interval of (427.3, 432.1). Copyright Springer Numéro de notice : A2007-182 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-006-0098-9 En ligne : https://doi.org/10.1007/s00190-006-0098-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28545
in Journal of geodesy > vol 81 n° 3 (March 2007) . - pp 179 - 187[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-07031 RAB Revue Centre de documentation En réserve L003 Disponible 266-07032 RAB Revue Centre de documentation En réserve L003 Disponible Practical geodesy: Part 1 The basics / Huibert-Jan Lekkerkerk in Geoinformatics, vol 10 n° 2 (01/03/2007)
[article]
Titre : Practical geodesy: Part 1 The basics Type de document : Article/Communication Auteurs : Huibert-Jan Lekkerkerk, Auteur Année de publication : 2007 Article en page(s) : pp 44 - 45 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] coordonnées rectangulaires
[Termes IGN] ellipsoïde (géodésie)
[Termes IGN] projection Universal Transverse Mercator
[Termes IGN] système de coordonnéesRésumé : (Auteur) In our series on satellite navigation, the importance of the geodetic parameters was briefly discussed. They play a crucial role not only in positioning, but in cartography (and therefore GIS) as well. The geodetic knowledge within most organizations seems to be at two distinct levels. First there is a highly abstract level, with geodesy and geodetic calculations being practiced by the ‘true’ geodesist. On the other hand there is the GIS specialist or surveyor who is responsible for production and is led by the information given by the supplier. This article provides a general introduction to the subject for the surveyor. Copyright GEOinformatics Numéro de notice : A2007-191 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28554
in Geoinformatics > vol 10 n° 2 (01/03/2007) . - pp 44 - 45[article]Voir aussiRéservation
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Code-barres Cote Support Localisation Section Disponibilité 262-07021 SL Revue Centre de documentation Revues en salle Disponible Official geoid undulations model: substitute for nationwide orthometric control network / G. Steinberg in GIM international, vol 21 n° 2 (February 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)PermalinkAufbau der neuen Landesvermessung der Schweiz 'LV95'. Teil 12 Landeshöhennetz 'LHN95' / A. Schlatter (2007)PermalinkCompensation d'un réseau de gravimétrie mesuré par le Service de Géodésie et de Nivellement de l'Institut Géographique National / J. Vienne (2007)PermalinkPermalinkPermalinkA data set to test geoid computation methods / Henri Duquenne (01/01/2007)PermalinkEtude des ondelettes multipôles de Poisson / Lâmân Lelégard (2007)PermalinkPermalinkPermalinkLocal 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 France [to the Symposium of the IAG Subcommission for Europe (EUREF) held in Riga, 14 - 17 June 2006] / Françoise Duquenne (01/01/2007)PermalinkNational 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)PermalinkPositionnement géodésique à haute fréquence de réseaux GNSS terrestres et marins / Stavros A. Melachroinos (2007)PermalinkProccedings of the 18th European VLBI for geodesy and astrometry working meeting, Vienna, 12-13 April 2007 / Johannes Böhm (2007)PermalinkPseudo-stochastic orbit modeling of low earth satellites using the Global Positioning System / Adrian Jäggi (2007)PermalinkQuelques définitions sur les systèmes de références et de coordonnées [diaporama] / Perrine Rouffiac (2007)PermalinkRapport du directeur sur l'activité et la gestion du Bureau International des Poids et Mesures (BIPM), 1er juillet 2006 - 30 juin 2007 / Bureau international des poids et mesures (2007)PermalinkRelative campaign during the International Comparison of Absolute Gravimeters ICAG-2005 and the strategy of data treatment combined with the absolute results / Zhiheng Jiang (2007)Permalink