Centre de documentation
scientifique

Geopotential models of the Earth from satellite tracking, altimeter and surface gravity observations / F.J. Lerch (1992)

Public Titre : Geopotential models of the Earth from satellite tracking, altimeter and surface gravity observations : GEM-T3 and GEM-T3S Type de document : Monographie Auteurs : F.J. Lerch, Auteur ; R.S. Nerem, Auteur ; B.H. Putney, Auteur ; T.L. Felsentreger, Auteur ; B.V. Sanchez, Auteur Editeur : Washington : National Aeronautics and Space Administration NASA Année de publication : 1992 Collection : NASA Technical Memorandum Importance : 119 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] champ de pesanteur terrestre [Termes IGN] données altimétriques [Termes IGN] géodésie spatiale [Termes IGN] levé gravimétrique [Termes IGN] modèle de géopotentiel [Termes IGN] orbitographie [Termes IGN] poursuite de satellite [Termes IGN] satellite d'observation de la mer [Termes IGN] surface de la mer [Termes IGN] surface topographique Index. décimale : 30.40 Géodésie physique Résumé : (Auteur) Improved models of the Earth's gravitational field have been developed from conventional tracking data (GEM-T3S) and from a combination of satellite tracking, satellite altimeter and surface gravirnetric data (GEM-T3). This combination model represents a significant improvement in the modeling of the gravity field at half-wavelengths of 300 km and longer. Both models are complete to degree and order 50. The GEM-T3 model provides more accurate computation of satellite orbital effects as well as giving superior geoidal representation from that achieved in any previous Goddard Earth Model. A description of the models, their development and an assessment of their accuracy is presented. The GEM-T3 model used altimeter data from GEOS-3 (1975-76), Seasat (1978) and Geosat (1986-87) in estimating the orbits, geoid and dynamic height fields. Other satellite tracking data are largely the same as was used to develop GEM-12, but contain certain important improvements in data treatment and expanded laser tracking coverage. Over 1300 arcs of tracking data from 31 different satellites have been used in the solution. Reliable estimates of the model uncertainties via error calibration and optimal data weighting techniques are discussed. Numéro de notice : 18474 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55397

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
18474-02	30.40	Livre	Centre de documentation	Géodésie	Disponible
18474-01	21.00	Livre	Centre de documentation	Technologies spatiales	Disponible

The GEM-T2 gravitational model / J.G. Marsh (1989)

Public Titre : The GEM-T2 gravitational model Type de document : Monographie Auteurs : J.G. Marsh, Auteur ; F.J. Lerch, Auteur ; B.H. Putney, Auteur ; et al., Auteur Editeur : Washington : National Aeronautics and Space Administration NASA Année de publication : 1989 Importance : 92 p. Format : 21 x 30 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] champ de pesanteur terrestre [Termes IGN] erreur systématique [Termes IGN] géoïde [Termes IGN] harmonique sphérique [Termes IGN] potentiel de pesanteur terrestre [Termes IGN] poursuite de satellite [Termes IGN] télémétrie laser [Termes IGN] TOPEX-Poseidon Index. décimale : 30.40 Géodésie physique Résumé : (Auteur) GEM-T2 is the latest in a series of Goddard Earth Models (GEM) of the terrestrial field. It was designed to bring modeling capabilities one step closer towards ultimately determining the TOPEX/POSEIDON satellite's radial position to an accuracy of 10-cm RMS. It also improves our models of the long wavelength geoid to support man' oceanographic and geophysical applications. GEM-T2 extends the spherical harmonic field to include more then 600 coefficients above degree 36 (which was the limit fo its predecessor, GEM-Tl). Like GEM-Tl, it was produced entirely from satellite tracking data, but it now uses nearly twice as many satellites (31 vs. 17), contain four times the number of observations (2.4 million), has twice the number of data arcs (1132), and utilizes precise laser tracking from 11 satellites. The estimation technique for the solution has been augmented to include an optimum data weighting procedure with automatic error calibration for the gravitational parameters. Results fok the GEM-T2 error calibration indicate significant improvement over previous satellite-only models. The error of commission in determining the geoid has been reduced from 155 cm in GEM-Tl.to 105 cm for GEM-T2 for the 36 x 36 portion of the field, and 141cm for the entire model. The orbital accuracies achieved using GEM-T2 are likewise improved. Also, the projected radial error on the TOPEX satellite orbit indicates 9.4 cm RMS for GEM-T2, compared to 24.1 cm for GEM-Tl. Numéro de notice : 18491 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55409

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
18491-01	30.40	Livre	Centre de documentation	Géodésie	Disponible