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Titre : Optical survey strategies and their application to space surveillance Type de document : Rapport Auteurs : Tim Flohrer, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2012 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 87 Importance : 178 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-34-5 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] débris spatial
[Termes IGN] orbitographie
[Termes IGN] stratégie
[Termes IGN] surveillanceIndex. décimale : 30.84 Applications de géodésie spatiale à l'atmosphère Résumé : (Editeur) [préface] This publication of Tim Flohrer focuses on strategies to search for space debris using optical observations and on the application of these strategies for space surveillance. The topic covers a wide range of aspects, starting with the actual detection of space debris on frames acquired by optical telescopes, and ending with the build-up and maintenance of a catalogue of orbit of these objects. An optimum search strategy aims at maximizing the number of observed objects of a reference population defined by the sizes and the orbital elements of the objects, by optimizing the observations sequences of telescopes at one or several sites. The design of the strategies must take into account geometrical boundary conditions – the objects must be visible from a given site – as well as radiometric constraints – the objects must be bright enough to be detected against the sky background. The build-up and maintenance of an orbit catalogue require periodic acquisition of astrometric positions of the catalogue objects. This may be achieved either by scheduling dedicated follow-up observations or by designing survey strategies in a way that enough observations of all objects are gained “incidentally”. All of the above-mentioned aspects are discussed in this publication. The author developed a software tool allowing to simulate search and observation strategies starting with the generation of individual observations and ending with a full orbit determination. This combination is rather unique and was a key element for the success of the strategies developed by Tim Flohrer. In addition to strategies for ground-based networks of telescopes the paper discusses concepts for the search of small size debris and for surveys of entire orbit regions using space-based optical sensors. The strategies to search for and monitor objects in the geostationary ring and the region of the global navigation satellite systems presented in this work became widely recognized in the scientific community. Concepts currently developed in the framework of the ESA initiative to establish an European space surveillance and tracking system are based to a great extent on Tim Flohrer’s work. Note de contenu : 1. Introduction and motivation
2. Space situational awareness, space debris, and space surveillance principles
2.1 Space situational awareness
2.2 Space surveillance
2.3 Space debris and its lifecycle
2.4 Space surveillance principles
2.5 Sensors with space surveillance capabilities
3. Observation fundamentals, data reduction, and orbit modelling
3.1 Reference systems
3.2 Orbital regimes
3.3 Observations
3.4 Orbits of artificial satellites
3.5 Two-line element (TLE) sets
4. Simulation environment for optical observations
4.1 PROOF
4.2 CelMech
4.3 Simulation environment
4.4 Application of the simulation environment to a proposed space-based optical observation scenario
4.5 Conclusions
5. Ground-based optical observation strategies
5.1 Population evolution
5.2 Accessibility of population
5.3 Proposed observation strategies
6. A system proposal for space-based optical space surveillance
6.1 SSA-related observation strategies with the SBO architecture
6.2 Radiometric characteristics of the SBO observing high altitudes
6.3 Coverage of reference populations
6.4 Orbit determination based on simulations
6.5 Conclusion
7. Conclusion and recommendations
A. Performance of initial orbit determination from space-based observations
B. Simulated orbit determination results for a system proposal for space-based optical space surveillanceNuméro de notice : 15701 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport de recherche En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-87.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62764 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 15701-01 30.84 Livre Centre de documentation Géodésie Disponible
Titre : Water vapor tomography using global navigation satellites systems Type de document : Thèse/HDR Auteurs : Donat Perler, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2012 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 84 Importance : 188 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-30-7 Note générale : Bibliographie
Doctoral ThesisLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] atmosphère terrestre
[Termes IGN] données GNSS
[Termes IGN] données météorologiques
[Termes IGN] modélisation spatiale
[Termes IGN] positionnement par GNSS
[Termes IGN] rayonnement électromagnétique
[Termes IGN] temps réel
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] tomographie par GPS
[Termes IGN] vapeur d'eauIndex. décimale : 30.84 Applications de géodésie spatiale à l'atmosphère Résumé : (Auteur) Water vapor plays an important role in the atmosphere. It is involved in many atmospheric processes and is a major contributor to the atmospheric energy budget and as such is a key quantity in numerical weather prediction (NWP) models. In recent years, NWP models gain in importance in hazard mitigation. But to provide precise quantitative forecasts, especially with respect to precipitation, we need accurate knowledge of the water vapor distribution in the atmosphere. Ground-based Global Navigation Satellite System (GNSS) tomography is a technique which can provide highly resolved and accurate water vapor profiles in space and time.
The main objective of this thesis is to develop new tomographic algorithms which fulfill the requirements to assimilate refractivity measurements derived from GNSS into NWP models. A new tomography software called AWATOS 2 has been implemented. It is an assimilation system for point and integrated refractivity measurements. The tomographic model in AWATOS 2 is formulated as a Kalman filter and different voxel parameterizations are provided. The new trilinear and spline-based parameterizations allow a more accurate representation of the refractivity field without considerably increasing the number of unknowns. Advantages of these new parameterizations are a) more accurate results, b) point observations need not to be interpolated to the voxel centers and c) the tomographic solutions are at least C0-continuous in space. The stochastic prediction model implemented in AWATOS 2 relies on in-situ measurements and NWP model data. The prediction model is evaluated and adjusted with respect to data from the high-resolution NWP model COSMO-2 and from balloon soundings in Europe. In addition, AWATOS 2 provides a sophisticated simulation framework to carry out synthetic tests based on simple refractivity fields and on NWP model data. The algorithms of AWATOS 2 are assessed with synthetic tests and with real data in a longterm study using one year of data. The synthetic tests have confirmed the theoretical properties of the model such as a bias-free solution in case of bias-free input data, fast convergence rates, and the capability to resolve vertical structures in the wet refractivity field. In the long-term study, a root-mean-square (RMS) error of 3.0 ppm (0.4 gm3 absolute humidity) is achieved with respect to the NWP model COSMO-7. The investigations have shown that the newly introduced voxel parameterizations lead to significantly more accurate results than the classical constant parameterization.
The improvements are about 15% with respect to balloon soundings and 5% with respect to NWP analysis data. The performance of the trilinear and spline-based parameterizations are similar. Further investigations have revealed the importance of a bias correction model. A newly developed bias correction model has decreased the RMS error with respect to the NWP model analysis from 4.9 ppm (0.7 gm3) to 3.0 ppm (0.4 gm3) using the spline parameterization. For the other parameterizations, the improvements are significantly smaller. The systematic differences corrected here are mainly caused by a) systematic differences between GPS tropospheric path delays and the NWP model data and b) by discretization errors. Another error source is related to the departure of the NWP model’s topography from the true one which can amount to several hundred meters in alpine areas. Investigations have shown that processes near the Earth’s surface have a strong impact on the wet refractivity. Therefore, differences between the true topography and that of the NWP model can cause substantial errors. This topic has to be addressed if GNSS observations are assimilated into NWP models in complex terrain. Considerable progress has been made in the field of low-cost GNSS receivers in recent years allowing to build dense networks at low costs. Furthermore, the existing GNSSs are improved and new ones are being launched. These developments offer new possibilities in GNSS tomography. With error analyses, the potential of such improvements for GNSS tomography have been investigated The use of GPS together with Galileo has the potential to improve the formal accuracy of the GNSS tomography by 10-15% compared to a GPS-only solution. In Switzerland, equipping the SwissMetNet with GNSS receivers would increase the number of GNSS stations from 31 to 91. This would improve the formal accuracy of the tomographic solution by about 20-25%. The investigations have shown that the improvements obtained by a more dense network and additional GNSSs are cumulative. Placing the stations on different altitudes and choosing locations with good satellite visibility are important to achieve accurate results and should be considered in the design of GNSS networks.
All investigations have demonstrated that accurate 4D distributions of the wet refractivity in the troposphere can be estimated with GNSS tomography. The work has also revealed the possibilities and limitations of GNSS tomography in view of the assimilation into NWP models and proposes solution strategies to overcome the limitations.Note de contenu : 1 Introduction
1.1 Significance of tropospheric water vapor measurements
1.2 A short review of the research in GNSS tomography
1.3 Objectives and structure of the thesis
2 Introduction to the propagation of radio waves in the atmosphere
2.1 Propagation of radio waves in the atmosphere
2.2 Modeling the path delay
3 GNSS tomography with the software package AWATOS 2
3.1 Overview of AWATOS 2
3.2 Preprocessing of GNSS double difference delays
3.3 Discretization of the refractivity field and parameterization
3.4 Modeling the refractivity field with the Kalman filter approach
3.5 Simulation capabilities in AWATOS 2
4 Overview of the data sets
4.1 GPS data
4.2 Balloon soundings
4.3 Synoptic network SwissMetNet
4.4 Numerical weather prediction model COSMO
5 Description of the wet refractivity field
5.1 Tempo-spatial variation of the wet refractivity field
5.2 Discretization Error
5.3 Representation of the discretization error .
5.4 Investigations of the process noise using a random walk model
5.5 Conclusions
6 Comparison of balloon sounding data and GNSS-derived zenith path delays
6.1 Error budget of meteorological sensors
6.2 Intercomparison between zenith path delays of different sources
6.3 Conclusions
7 Potential of new GNSSs and dense networks in view of GNSS tomography
7.1 Configurations
7.2 Methods
7.3 Results and discussion
7.4 Conclusions
8 Simulation-based evaluation of the new tomographic algorithms
8.1 Theoretical considerations of the resolvability of vertical structures
8.2 Experiments with simulated data
8.3 Conclusions
9 Evaluation of the GPS tomography with a long-term study
9.1 Configuration and evaluation methods
9.2 Results and discussion
9.3 Bias correction model and its evaluation
9.4 Conclusions
10 Conclusions
11 OutlookNuméro de notice : 15546 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-006875504 En ligne : http://dx.doi.org/10.3929/ethz-a-006875504 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62758 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 15546-01 30.84 Livre Centre de documentation Géodésie Disponible Analysis of long-term GPS observations in Greece (1993-2009) and geodynamic implications for the Eastern Mediterranean / Michael D. Müller (2011)
Titre : Analysis of long-term GPS observations in Greece (1993-2009) and geodynamic implications for the Eastern Mediterranean Type de document : Rapport Auteurs : Michael D. Müller, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2011 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 82 Importance : 186 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-28-4 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Athènes
[Termes IGN] champ de vitesse
[Termes IGN] collocation par moindres carrés
[Termes IGN] Egée, mer
[Termes IGN] Grèce
[Termes IGN] méthode des éléments finis
[Termes IGN] Péloponnèse
[Termes IGN] séisme
[Termes IGN] vitesseIndex. décimale : 30.82 Applications géophysiques de géodésie spatiale Résumé : (Auteur) The Global Positioning System (GPS) is used to determine rates of crustal motion in the Hellenic plate boundary zone since the late eighties. The zone comprises Greece and its adjacent regions. It is characterized by the interaction of the Eurasian, Anatolian and Nubian plates moving relative to each other. Tectonic processes associated with this motion cause the highest seismic activity of Europe. Nine earthquakes with magnitude six or higher occurred within this region in the period 2006 to 2011. International efforts are being made to achieve a better understanding of the origin and characteristics of ongoing seismotectonic processes. The ETH Zurich has taken active part in these efforts. Results achieved so far provide valuable boundary conditions for geodynamic modeling. In close collaboration with other institutes an extensive GPS network has been established and periodically remeasured. The network consists of campaign-type and continuous GPS sites. The corresponding data record has been significantly extended in the course of the thesis. A 16 year record of GPS data (19932009) is available now for Greece. In its first part the thesis deals with the evaluation of the data record. The strategy of GPS analysis was enhanced compared to proceeding projects by applying recent GPS processing models and improving postprocessing procedures. The concept of including data of numerous IGS and EUREF sites located in Europe, North Africa and the Middle East was continued. This allowed for a precise alignment of the GPS network to a global reference frame (ITRF2005), the reduction of processing induced systematic signals and the determination of a pole of rotation for the Eurasian plate.
An improved kinematic field was derived which was analyzed in terms of slowly deforming regions by using a block model. The modeling provides several insights. For instance, northwestern Greece rotates clockwise (cw) and the region south of the North Aegean trough (NAT) rotates counterclockwise (ccw) relative to Eurasia. Both areas form blocks with small internal deformation. Moreover, they describe the western termination of the North Aegean trough. A large part of ongoing deformation is located in confined regions.
The GPS derived deformation field provides information about ongoing tectonic processes. These include N-S extension between Northern Greece and the Gulf of Corinth and dextral shear strain in the North Aegean sea as well as along the Kefalonia fault zone in the Ionian sea. New results concerning ongoing deformation processes were achieved in the Southeast Aegean sea and in Northern Greece. Pronounced N-S extension (100 nstrain/yr) was determined across the Mygdonian graben. NNW-SSE extension amounting to 150 nstrain/yr was found between the islands of Kalymnos and Tilos in the SE Aegean sea.
The NAT and the Kefalonia fault zone are among the most pronounced transform faults in the Hellenic plate boundary zone. Rates of closely located GPS sites were used for the estimation of the slip rates and locking depths of the structures. Four profiles across the NAT show a decrease of slip rates from the Ganos fault (23 mm/yr) towards the southwestern edge of the Sporades basin (<5 mm/yr). The geodetic results provide further evidence that the NAT forms the westward continuation of the North Anatolian fault zone commencing at the Saros basin. The decrease of slip rates west of the Chalkidiki peninsula is related to a different orientation of the NAT and to NNE-SSW extension in the Sporades basin. Finite element models were used to relate GPS rates to basic geodynamic models. The first model I focused at the analysis of the subduction rate near the central Hellenic trench. The results point to a largely uncoupled interface between the Nubian and Aegean plates. The second model quantifies the slip rates along the three major NE-SW to ENE-WSW trending transform faults in the North Aegean sea. Rates amounting to 21 mm/yr were derived for the NAT, 10 mm/yr for the Skyros- Edremit fault and 4 mm/yr for the Psara-Lesvos fault. Moreover, the model reveals additional deformation zones such as NNE-SSW extension in the Sporades basin. The derived GPS rates and the conducted analyses improve the current understanding of seismotectonic processes in Greece. The investigations also highlight remaining problems and bring forward new ideas which will ultimately be valuable for further analysis and assessment of natural hazard in Greece.Note de contenu : 1 Introduction
1.1 State of research
1.2 Goals
2 Geologic setting
2.1 Evolution of the central and eastern Mediterranean
2.2 Tectonic framework of Greece
3 GPS data evaluation
3.1 Description of relevant GPS networks
3.1.1 Campaign-type GPS network in Greece and southern Bulgaria
3.1.2 Continuous GPS networks in Greece
3.1.3 IGS and EUREF sites
3.2 Strategy of GPS data processing
3.3 Definition of the geodetic datum
3.4 Velocity estimation of CGPS sites
3.4.1 Introduction
3.4.2 Discontinuities in position time series
3.4.3 Removing outliers
3.4.4 Exclusion periods
3.4.5 Estimation of velocities and offsets
3.4.6 Reduction of apparent scale changes of the processed GPS network
3.4.7 Scaling of formal errors of velocities
3.5 Velocity estimation of campaign-type GPS sites
3.6 Factors affecting the velocity estimates
3.6.1 Tracking performance of GPS sites
3.6.2 Used orbits and earth orientation parameters
3.6.3 Campaign-type data of the years 1993 and 1994
3.7 Concluding remarks
4 Kinematic field in Greece (19932009)
4.1 Introduction
4.2 Euler vector and estimation of a pole of rotation for Eurasia (ITRF2005)
4.3 Kinematic block model for Greece
4.4 Kinematic field and modeling in the North Aegean domain
4.4.1 Kinematic field
4.4.2 Slip rates and locking depths along the North Aegean trough
4.5 Kinematics along the Hellenic trench system
4.5.1 Ionian islands, Western Greece and NW Peloponnesos
4.5.2 Southern Peloponnesos and South Aegean sea
4.6 Vertical motion in Greece
4.7 Concluding remarks
5 Strain rates derived by using the method of collocation
5.1 Least-squares collocation
5.2 Velocity and strain rate fields calculation implemented in the program 'strain'
5.3 Strain rates and differential rotations in Greece
5.4 Concluding remarks
6 Seismic signals in GPS time series
6.1 Introduction
6.2 Estimation of earthquake displacements
6.3 Analytical surface dislocation model
6.4 Earthquakes in the Aegean domain
6.4.1 1999 Ms 5.9 Athens earthquake
6.4.2 2001 Mw 6.4 Skyros earthquake
6.4.3 2008 Mw 6.4 Rhodes earthquake
6.5 Earthquakes in the Ionian sea
6.5.1 1997 Mw 6.6 Strofades earthquake
6.5.2 2003 Mw 6.2 Lefkada earthquake
6.5.3 2006 Zakynthos earthquake series
6.5.4 2008 Mw 6.4 NW Peloponnesos earthquake
6.5.5 Comparison of seismicity and interseismic strain rates
6.6 Concluding remarks
7 Finite element models
7.1 Finite element method
7.1.1 Basic theory
7.1.2 Displacement-based finite element analysis
7.2 Physical properties of a model lithosphere
7.2.1 Introductory notes
7.2.2 Elasticity
7.2.3 Brittle failure
7.2.4 Ductile deformation
7.2.5 Temperature in the continental lithosphere
7.3 Interaction between the overriding and the subducting plate at the central Hellenic trench
7.3.1 Geodetic constraints
7.3.2 Developed finite element model
7.4 3D finite element model of the North Aegean sea
7.4.1 Introduction
7.4.2 Model set up
7.4.3 Results
7.5 Concluding remarks
8 ConclusionsNuméro de notice : 14311 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport de recherche En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-82.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62654 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 14311-01 30.82 Livre Centre de documentation Géodésie Disponible Combined analysis of observations from different global navigation satellite systems / Michael Meindl (2011)
Titre : Combined analysis of observations from different global navigation satellite systems Type de document : Monographie Auteurs : Michael Meindl, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2011 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 83 Importance : 150 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-27-7 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse combinatoire (maths)
[Termes IGN] analyse comparative
[Termes IGN] application informatique
[Termes IGN] Bernese
[Termes IGN] compensation par moindres carrés
[Termes IGN] données GNSS
[Termes IGN] erreur systématique
[Termes IGN] système de positionnement par satellites
[Termes IGN] traitement de données GNSSIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Résumé : (Auteur) [préface] La présente publication de M. Michael Meindl est dédiée à l'analyse combinée de différents GNSS (Système Global de Navigation par Satellite). [...] Le travail de M. Meindl se divise en trois parties. Après la description du principe de mesure et de plusieurs systèmes, la première partie est consacrée au développement de l'équation de l'observation GNSS dans sa pleine extension. L'identification des paramètres identiques entre les systèmes considérés et ceux qui diffèrent fait l'objet d'une attention particulière. De cette discussion résulte une liste de biais entre les différents systèmes, fréquences/signaux et techniques d'acquisition des récepteurs. Dans la seconde partie, sur la base des résultats de la première partie, M. Meindl expose les raisons de faire évoluer un logiciel GNSS capable de traiter des données GPS double fréquence uniquement vers un logiciel flexible capable de traiter de manière combinée des données de plusieurs GNSS. Une première section décrit certains aspects stratégiques d'un tel logiciel ainsi que son architecture. Une seconde section se concentre plus spécifiquement sur l'extension réalisée sur le logiciel Bernese. Dans la troisième partie, M. Meindl a analysé l'influence de la longueur de l'intervalle de temps considéré dans le traitement des données (usuellement fixée à 24 heures pour des raisons pratiques) sur les résultats de solutions mono- et multi-GNSS. Les données d'un réseau global de 92 stations capables d'observer les deux GNSS opérationnels à ce jour, c'està- dire GPS et GLONASS, ont été traitées dans ce sens, sur une période de trois ans. Dans un premier temps, l'auteur analyse les caractéristiques essentielles des solutions (telles que le nombre d'observations, la vitesse de répétition des constellations et leur géométrie). Suit l'analyse des résultats tels que par exemple les coordonnées des stations ou les orbites des satellites. L'auteur démontre que l'analyse combinée de données GPS et GLONASS prévaut sur celle de données d'un système unique. Note de contenu : 1 Introduction
Part I Global Navigation Satellite Systems
2 An Introduction to Global Navigation Satellite Systems
2.1 Navigation Principles
2.2 System Segments and Configuration
2.3 Satellite Orbits and Orbital Motion
2.4 Global Navigation Satellite Systems in Comparison
2.5 Motivation and Benefits of Using Different GNSS
2.6 Institutions Relevant to this Work
3 GNSS Data Processing
3.1 Fundamental Observation Equations
3.2 Linear Combinations of Observations
3.3 Differences of Observations
3.4 Biases in GNSS Data Processing
3.5 Least-squares Adjustment in Overview
Part II Realizing a Multi-GNSS Analysis Software for Scientific Purposes
4 Concepts and Design
4.1 The Bernese GPS Software
4.2 Requirements for a Multi-GNSS Software
4.3 Design Principles and Software Architecture
5 Practical Realization
5.1 Initial Situation
5.2 Software Implementations
5.3 Summary
Part III Combined Analysis of Observations from GPS and GLONASS
6 Setup of Experiments
6.1 Motivation
6.2 Design of the Study
6.3 Summary and Key Figures
6.4 Geometry-induced Variations in the Observation Material
7 Results and Discussion
7.1 Station Coordinates
7.2 Orbits and Geocenter
7.3 Earth Rotation Parameters
7.4 Orbit Validation with Satellite Laser Ranging
8 Summary and ConclusionsNuméro de notice : 14312 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-83.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62655 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 14312-01 30.61 Livre Centre de documentation Géodésie Disponible Documents numériques
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14312_combined_analysis_of_observations_meindl.pdfAdobe Acrobat PDF Global gravity field determination using the GPS measurements made onboard the low Earth orbiting satellite CHAMP / Lars Prange (2010)
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 saisonnièreIndex. 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 conclusionsNuméro 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 Exemplaires(1)
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