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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

Optimum data weighting and error calibration for estimation of gravitational parameters / F.J. Lerch (1989)

Public Titre : Optimum data weighting and error calibration for estimation of gravitational parameters Type de document : Monographie Auteurs : F.J. Lerch, Auteur Editeur : Washington : National Aeronautics and Space Administration NASA Année de publication : 1989 Importance : 27 p. Format : 21 x 30 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] erreur systématique [Termes IGN] estimation statistique [Termes IGN] étalonnage des données [Termes IGN] méthode des moindres carrés [Termes IGN] pondération Index. décimale : 30.40 Géodésie physique Résumé : (Auteur) A new technique has been developed for the weighting of data from satellite tracking systems in order to obtain an optimum least squares solution and an error calibration for the solution parameters. Data sets from optical, electronic, and laser systems on 17 satellites in GEM-Tl (Goddard Earth Model, 36x36 spherical harmonic field) have been employed toward application of this technique for gravity field parameters. Also, GEM-T2 (31 satellites) was recently computed as a direct application of the method and is summarized here. The method employs subset solutions of the data associated with the complete solution and uses an algorithm to adjust the data weights by requiring the differences of parameters between solutions to agree with their error estimates. With the adjusted weights the process provides for an automatic calibration of the error estimates for the solution parameters. The data weights derived are generally much smaller than corresponding weights obtained from nominal values of observation accuracy or residuals. Independent tests show significant improvement for solutions with optimal weighting as compared to the nominal weighting. The technique is general and may be applied to orbit parameters, station coordinates, or other parameters than the gravity model Numéro de notice : 18489 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55407

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
18489-01	30.40	Livre	Centre de documentation	Géodésie	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

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

Geometrical geodesy techniques in Goddard Earth Models [GEM] / F.J. Lerch (1973)

Public Titre : Geometrical geodesy techniques in Goddard Earth Models [GEM] : preprint X-592-73-339 Type de document : Monographie Auteurs : F.J. Lerch, Auteur Editeur : Greenbelt (Maryland) : Goddard Space Flight Center Année de publication : 1973 Importance : 35 p. Format : 20 x 27 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] données hétérogènes [Termes IGN] figure de la Terre [Termes IGN] géodésie mathématique [Termes IGN] méthode des moindres carrés [Termes IGN] régression linéaire Index. décimale : 30.40 Géodésie physique Numéro de notice : 43033 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63860

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
43033-01	30.40	Livre	Centre de documentation	Géodésie	Disponible