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GPS-derived orbits for the GOCE satellite / Heike Bock in Journal of geodesy, vol 85 n° 11 (November /2011)  

Public [article]  inJournal of geodesy > vol 85 n° 11 (November /2011) . - pp 807 - 818 Titre : GPS-derived orbits for the GOCE satellite Type de document : Article/Communication Auteurs : Heike Bock, Auteur ; Adrian Jäggi, Auteur ; U. Meyer, Auteur ; P. Visser, Auteur ; et al., Auteur Année de publication : 2011 Article en page(s) : pp 807 - 818 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales [Termes IGN] antenne GPS [Termes IGN] GOCE [Termes IGN] orbite basse [Termes IGN] orbitographie [Termes IGN] orbitographie par GNSS [Termes IGN] positionnement cinématique [Termes IGN] série temporelle [Termes IGN] télémétrie laser sur satellite Résumé : (Auteur) The first ESA (European Space Agency) Earth explorer core mission GOCE (Gravity field and steady-state Ocean Circulation Explorer) was launched on 17 March 2009 into a sun-synchronous dusk–dawn orbit with an exceptionally low initial altitude of about 280 km. The onboard 12-channel dual-frequency GPS (Global Positioning System) receiver delivers 1 Hz data, which provides the basis for precise orbit determination (POD) for such a very low orbiting satellite. As part of the European GOCE Gravity Consortium the Astronomical Institute of the University of Bern and the Department of Earth Observation and Space Systems are responsible for the orbit determination of the GOCE satellite within the GOCE High-level Processing Facility. Both quick-look (rapid) and very precise orbit solutions are produced with typical latencies of 1 day and 2 weeks, respectively. This article summarizes the special characteristics of the GOCE GPS data, presents POD results for about 2 months of data, and shows that both latency and accuracy requirements are met. Satellite Laser Ranging validation shows that an accuracy of 4 and 7 cm is achieved for the reduced-dynamic and kinematic Rapid Science Orbit solutions, respectively. The validation of the reduced-dynamic and kinematic Precise Science Orbit solutions is at a level of about 2 cm. Numéro de notice : A2011-469 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0484-9 Date de publication en ligne : 26/05/2011 En ligne : https://doi.org/10.1007/s00190-011-0484-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31363 [article]

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Validation of GOCE gravity field models by means of orbit residuals and geoid comparisons / Thomas Gruber in Journal of geodesy, vol 85 n° 11 (November /2011)  

Public [article]  inJournal of geodesy > vol 85 n° 11 (November /2011) . - pp 845 - 860 Titre : Validation of GOCE gravity field models by means of orbit residuals and geoid comparisons Type de document : Article/Communication Auteurs : Thomas Gruber, Auteur ; P. Visser, Auteur ; C. Ackermann, Auteur ; M. Hosse, Auteur Année de publication : 2011 Article en page(s) : pp 845 - 860 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse comparative [Termes IGN] analyse de variance [Termes IGN] champ de pesanteur terrestre [Termes IGN] données GOCE [Termes IGN] données GRACE [Termes IGN] géoïde gravimétrique [Termes IGN] géoïde terrestre [Termes IGN] harmonique sphérique [Termes IGN] limite de résolution géométrique [Termes IGN] orbitographie [Termes IGN] résidu Résumé : (Auteur) Three GOCE-based gravity field solutions have been computed by ESA’s high-level processing facility and were released to the user community. All models are accompanied by variance-covariance information resulting either from the least squares procedure or a Monte-Carlo approach. In order to obtain independent external quality parameters and to assess the current performance of these models, a set of independent tests based on satellite orbit determination and geoid comparisons is applied. Both test methods can be regarded as complementary because they either investigate the performance in the long wavelength spectral domain (orbit determination) or in the spatial domain (geoid comparisons). The test procedure was applied to the three GOCE gravity field solutions and to a number of selected pre-launch models for comparison. Orbit determination results suggest, that a pure GOCE gravity field model does not outperform the multi-year GRACE gravity field solutions. This was expected as GOCE is designed to improve the determination of the medium to high frequencies of the Earth gravity field (in the range of degree and order 50 to 200). Nevertheless, in case of an optimal combination of GOCE and GRACE data, orbit determination results should not deteriorate. So this validation procedure can also be used for testing the optimality of the approach adopted for producing combined GOCE and GRACE models. Results from geoid comparisons indicate that with the 2 months of GOCE data a significant improvement in the determination of the spherical harmonic spectrum of the global gravity field between degree 50 and 200 can be reached. Even though the ultimate mission goal has not yet been reached, especially due to the limited time span of used GOCE data (only 2 months), it was found that existing satellite-only gravity field models, which are based on 7 years of GRACE data, can already be enhanced in terms of spatial resolution. It is expected that with the accumulation of more GOCE data the gravity field model resolution and quality can be further enhanced, and the GOCE mission goal of 1–2 cm geoid accuracy with 100 km spatial resolution can be achieved. Numéro de notice : A2011-470 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0486-7 Date de publication en ligne : 08/06/2011 En ligne : https://doi.org/10.1007/s00190-011-0486-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31364 [article]

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