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Validation of Galileo orbits using SLR with a focus on satellites launched into incorrect orbital planes / Krzysztof Sosnica in Journal of geodesy, vol 92 n° 2 (February 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 2 (February 2018) . - pp 131 - 148 Titre : Validation of Galileo orbits using SLR with a focus on satellites launched into incorrect orbital planes Type de document : Article/Communication Auteurs : Krzysztof Sosnica, Auteur ; Lars Prange, Auteur ; Kamil Kazmierski, Auteur ; Grzegorz Bury, Auteur ; et al., Auteur Année de publication : 2018 Article en page(s) : pp 131 - 148 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales [Termes IGN] données TLS (télémétrie) [Termes IGN] Galileo [Termes IGN] orbite Résumé : (Auteur) The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, highly eccentric orbital plane with a lower than nominal inclination angle. All Galileo satellites are equipped with satellite laser ranging (SLR) retroreflectors which allow, for example, for the assessment of the orbit quality or for the SLR–GNSS co-location in space. The number of SLR observations to Galileo satellites has been continuously increasing thanks to a series of intensive campaigns devoted to SLR tracking of GNSS satellites initiated by the International Laser Ranging Service. This paper assesses systematic effects and quality of Galileo orbits using SLR data with a main focus on Galileo satellites launched into incorrect orbits. We compare the SLR observations with respect to microwave-based Galileo orbits generated by the Center for Orbit Determination in Europe (CODE) in the framework of the International GNSS Service Multi-GNSS Experiment for the period 2014.0–2016.5. We analyze the SLR signature effect, which is characterized by the dependency of SLR residuals with respect to various incidence angles of laser beams for stations equipped with single-photon and multi-photon detectors. Surprisingly, the CODE orbit quality of satellites in the incorrect orbital planes is not worse than that of nominal FOC and IOV orbits. The RMS of SLR residuals is even lower by 5.0 and 1.5 mm for satellites in the incorrect orbital planes than for FOC and IOV satellites, respectively. The mean SLR offsets equal −44.9,−35.0, and −22.4 mm for IOV, FOC, and satellites in the incorrect orbital plane. Finally, we found that the empirical orbit models, which were originally designed for precise orbit determination of GNSS satellites in circular orbits, provide fully appropriate results also for highly eccentric orbits with variable linear and angular velocities. Numéro de notice : A2018-058 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1050-x En ligne : https://doi.org/10.1007/s00190-017-1050-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89391 [article]

Global gravity field determination using the GPS measurements made onboard the low Earth orbiting satellite CHAMP / Lars Prange (2010)  

Public Titre : Global gravity field determination using the GPS measurements made onboard the low Earth orbiting satellite CHAMP Type de document : Rapport Auteurs : Lars Prange, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2010 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 81 Importance : 212 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-25-3 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] champ de pesanteur terrestre [Termes IGN] données CHAMP [Termes IGN] données GPS [Termes IGN] Global Positioning System [Termes IGN] gravimétrie spatiale [Termes IGN] modèle de géopotentiel [Termes IGN] orbite basse [Termes IGN] orbitographie [Termes IGN] positionnement par GPS [Termes IGN] validation des données [Termes IGN] variation saisonnière Index. décimale : 30.40 Géodésie physique Résumé : (Auteur) The major goal of this work was to to generate "the best possible" static CHAMP-only gravity field model using most of the openly available CHAMP data. Firstly we wanted to assess the full potential but also the limitations of CHAMP data and a CHAMP-like satellite mission for gravity field determination. Secondly we wanted to gain as much insight as possible in determining gravity fields (static and time variable) from space-based GNSS data in general, because several current and future satellite missions (dedicated to gravity field research, but also non-dedicated) equipped with GNSS receivers could benefit from improvements made here. We believe to have come close to achieving these goals by generating, validating, and publishing the static Earth gravity field models AIUB-CHAMPOIS, AIUB-CHAMP02S, and AIUB-CHAMP03S. Furthermore, the largest constituents of the seasonal gravity field variations could be retrieved from CHAMP data, as well. The Celestial Mechanics Approach (CMA) was successfully applied for gravity field determination. Note de contenu : 1 Introduction 2 Measuring the Earth's gravity field 2.1 Terrestrial geodesy 2.2 Satellite geodesy 2.2.1 Optical observations 2.2.2 Microwave methods 2.2.3 Satellite Laser Ranging (SLR) 2.2.4 Satellite altimetry 2.2.5 High-low SST of CHAMP 2.2.6 Low-low SST with GRACE 2.2.7 Satellite gradiometry with GOCE 3 Orbit determination and gravity field recovery 3.1 Least squares adjustment 3.1.1 Basic concept 3.1.2 LSA techniques 3.2 Coordinate systems 3.2.1 Geocentric quasi-inertial system 3.2.2 Earth-fixed coordinate system 3.2.3 Satellite-fixed coordinate system 3.3 Satellite orbits 3.3.1 Dynamic orbits 3.3.2 Reduced-dynamic orbits 3.3.3 Kinematic orbits 3.4 The equation of motion 3.5 Spherical harmonic representation of the gravitational potential 3.6 Orbit and gravity field determination 3.6.1 Numerical integration of the primary equations 3.6.2 Numerical integration of the variational equations 4. Global Positioning System - GPS 4.1 History 4.2 Basic measurement principle 4.3 GPS orbit constellation and satellites 4.4 GPS signals 4.5 Modeling GPS observables 4.5.1 Observation equations 4.5.2 Observation differences 4.5.3 Linear combinations 4.6 The International GNSS Service (IGS) 4.7 Bernese GPS Software (BSW) 5 Data processing 5.1 Generation of the A1UB-CHAMP01S gravity field model 5.1.1 Data Screening 5.1.2 Gravity field recovery 5.1.3 The AIUB-CHAMP01S gravity field model 5.2 Generation of the AIUB-CHAMP02S gravity field model 5.2.1 GNSS model changes 5.2.2 GPS orbit reprocessing 5.2.3 GPS satellite clock reprocessing 5.2.4 CHAMP orbit determination 5.2.5 AIUB-CHAMP02S gravity field recovery 5.2.6 The AIUB-CHAMP02S gravity field model 5.3 Generation of the AIUB-CHAMP03S gravity field model 5.3.1 Estimation of high-rate GPS satellite clock corrections 5.3.2 CHAMP orbit determination 5.3.3 Data screening and gravity field recovery 5.3.4 The AIUB-CHAMP03S gravity field model 6 Studies and experiments 6.1 Studies related to A1UB-C11AMP01S 6.1.1 Orbit modeling with arc-specific parameters 6.1.2 Modeling of non-gravitational perturbations with dynamic force models 6.1.3 Accelerometer data 6.1.4 Simulation study 6.1.5 Observation weights . 6.1.6 Influence of the a priori gravity field model 6.1.7 Screening the kinematic positions 6.1.8 Quality variations in monthly gravity field solutions 6.1.9 Summary and discussion of the IUB-CHAMPOlS-related studies 6.2 Experiments related to AIUB-CI1AMP02S 6.2.1 The impact of GNSS model changes 6.2.2 Inconsistency in the low degree harmonics 6.2.3 Simulation study 6.2.4 Latitude dependency of the observation scenario 6.2.5 Summary and conclusion of the AIUB-CHAMP02S-related studies 6.3 Experiments related to AIUB-CHAMP03S .. 6.3.1 Influence of empirical PCV-models on gravity field recovery using CHAMP GPS data .. 6.3.2 Elevation-dependent weighting 6.3.3 Observation sampling 6.3.4 Inter-epoch correlations of kinematic positions 6.3.5 Position differences vs. positions 6.3.6 Impact of observations of eclipsing GPS satellites on CHAMP gravity field recovery ... 6.3.7 Temporal variations of the Earth's gravity field 6.3.8 Recovery of the low degree harmonics 6.3.9 Summary of the experiments related to AIUB-CHAMP03S 7 Gravity field validation 7.1 Validation methods 7.1.1 Formal errors 7.1.2 Comparison with other gravity field models 7.1.3 Comparison with ground data 7.1.4 Altimetry data 7.1.5 Orbit determination 7.2 Validation of AIUB-CHAMP01S 7.2.1 Internal validation . 7.2.2 External validation 7.3 Validation of AIUB-CHAMP02S 7.3.1 Internal validation 7.3.2 External validation 7.4 Validation of AIUB-CHAMP03S 7.4.1 Internal validation 7.4.2 External validation 8 Summary and conclusions Numéro de notice : 10370 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport de recherche En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-81.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62409

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