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Simulation study of a follow-on gravity mission to GRACE / B. Loomis in Journal of geodesy, vol 86 n° 5 (May 2012)
[article]
Titre : Simulation study of a follow-on gravity mission to GRACE Type de document : Article/Communication Auteurs : B. Loomis, Auteur ; R. Nerem, Auteur ; Scott B. Luthcke, Auteur Année de publication : 2012 Article en page(s) : pp 319 - 335 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] crénelage
[Termes IGN] données GRACE
[Termes IGN] masse de la Terre
[Termes IGN] simulationRésumé : (Auteur) The gravity recovery and climate experiment (GRACE) has been providing monthly estimates of the Earth’s time-variable gravity field since its launch in March 2002. The GRACE gravity estimates are used to study temporal mass variations on global and regional scales, which are largely caused by a redistribution of water mass in the Earth system. The accuracy of the GRACE gravity fields are primarily limited by the satellite-to-satellite range-rate measurement noise, accelerometer errors, attitude errors, orbit errors, and temporal aliasing caused by un-modeled high-frequency variations in the gravity signal. Recent work by Ball Aerospace & Technologies Corp., Boulder, CO has resulted in the successful development of an interferometric laser ranging system to specifically address the limitations of the K-band microwave ranging system that provides the satellite-to-satellite measurements for the GRACE mission. Full numerical simulations are performed for several possible configurations of a GRACE Follow-On (GFO) mission to determine if a future satellite gravity recovery mission equipped with a laser ranging system will provide better estimates of time-variable gravity, thus benefiting many areas of Earth systems research. The laser ranging system improves the range-rate measurement precision to ~0.6 nm/s as compared to ~0.2 ?m/s for the GRACE K-band microwave ranging instrument. Four different mission scenarios are simulated to investigate the effect of the better instrument at two different altitudes. The first pair of simulated missions is flown at GRACE altitude (~480 km) assuming on-board accelerometers with the same noise characteristics as those currently used for GRACE. The second pair of missions is flown at an altitude of ~250 km which requires a drag-free system to prevent satellite re-entry. In addition to allowing a lower satellite altitude, the drag-free system also reduces the errors associated with the accelerometer. All simulated mission scenarios assume a two satellite co-orbiting pair similar to GRACE in a near-polar, near-circular orbit. A method for local time variable gravity recovery through mass concentration blocks (mascons) is used to form simulated gravity estimates for Greenland and the Amazon region for three GFO configurations and GRACE. Simulation results show that the increased precision of the laser does not improve gravity estimation when flown with on-board accelerometers at the same altitude and spacecraft separation as GRACE, even when time-varying background models are not included. This study also shows that only modest improvement is realized for the best-case scenario (laser, low-altitude, drag-free) as compared to GRACE due to temporal aliasing errors. These errors are caused by high-frequency variations in the hydrology signal and imperfections in the atmospheric, oceanographic, and tidal models which are used to remove unwanted signal. This work concludes that applying the updated technologies alone will not immediately advance the accuracy of the gravity estimates. If the scientific objectives of a GFO mission require more accurate gravity estimates, then future work should focus on improvements in the geophysical models, and ways in which the mission design or data processing could reduce the effects of temporal aliasing. Numéro de notice : A2012-241 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0521-8 Date de publication en ligne : 28/10/2011 En ligne : https://doi.org/10.1007/s00190-011-0521-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31687
in Journal of geodesy > vol 86 n° 5 (May 2012) . - pp 319 - 335[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2012051 RAB Revue Centre de documentation En réserve L003 Disponible Modelos armonicos no lineales para series temporales geodéticas = Non-linear harmonic models for geodetic time series / P.A. Martinez-Ortiz (2011)
Titre : Modelos armonicos no lineales para series temporales geodéticas = Non-linear harmonic models for geodetic time series Type de document : Thèse/HDR Auteurs : P.A. Martinez-Ortiz, Auteur ; J.M. Fernadiz Leal, Directeur de thèse Editeur : Alicante : Escuella politécnica superior Année de publication : 2011 Importance : 402 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Espagnol (spa) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] analyse harmonique
[Termes IGN] analyse spectrale
[Termes IGN] bruit blanc
[Termes IGN] bruit rose
[Termes IGN] géocentre
[Termes IGN] marée terrestre
[Termes IGN] masse de la Terre
[Termes IGN] Matlab
[Termes IGN] modèle non linéaire
[Termes IGN] positionnement par GPS
[Termes IGN] série temporelle
[Termes IGN] système de référence géodésiqueIndex. décimale : THESE Thèses et HDR Résumé : (Auteur) The dissertation addresses the development of new methods and software for the spectral analysis of scalar or vectorial time series, with emphasis in the applications of geodetic interest. The starting point can be placed in the method introduced by Harada and Fukushima for the non-linear analysis of time series, which allows the recursive detection of frequencies and their associated amplitudes and phases as well as the secular mixed Fourier terms when found in the signal. That method is extended in different ways, allowing the treatment of series affected by auto correlated noise with a power law, either evenly or unevenly spaced. This is made both at the level of frequency detection and non-linear fitting. Reduction of the computational overhead is also obtained. The theoretical work is accompanied by the developing of comprehensive and specialized software for such non-linear harmonic analysis of time series using the MATLAB programming language. Much of the tools we can find today for analyzing these periodic time series are valid only for certain types whereas the programs in the thesis can be applied to oddly spaced series in the presence of combinations of white and flicker noise. The new methods and routines are used for analyzing some interesting series as those ones describing the celestial pole offsets, the geocentre variations due to the redistribution of water mass on the Earth's surface, the excess of the length of day, continental water flux and the positions of GPS stations, among others. We estimate harmonic models that explain each one of these phenomena in the considered time domain and allow us to draw conclusions of their behavior. Note de contenu : Agradecimientos
Resumen
Abstract
I MODELOS ARMÓNICOS NO LINEALES PARA SE RÍES TEMPORALES GEODÉTICAS
1. Introducción
1.1. Objetivos y metodología
1.2. Contenidos
2. El problema de la detección de señales
2.1. Definición de serie temporal
2.1.1. Componentes de una serie temporal
2.1.2. Componente de ruido
2.2. Técnicas para el estudio de series temporales
2.2.1. Análisis clásico
2.2.2. Análisis espectral
2.2.3. Análisis wavelet
2.3. El problema de la detección de señales
2.3.1. Periodograma de Lomb
2.3.2. Dominio de frecuencia
3. Análisis armónico no lineal
3.1. Introducción
3.2. Descripción del método
3.2.1. Función objetivo y funciones base
3.2.2. Solución mínimo cuadrática
3.2.3. Optimización no lineal: Algoritmo BFGS
3.2.4. Extracción de frecuencias
3.3. Incertidumbre
3.4. Generalización
3.5. Tratamiento de los términos periódicos de corta frecuencia
4. Variaciones del polo celeste
4.1. Modelo de precesión-nutación IAU1980
4.1.1. Introducción
4.1.2. Descripción de los datos
4.1.3. Características del análisis y resultados
4.1.4. Conclusiones
4.2. Modelo de precesión-nutación IAU2000
4.2.1. Introducción
4.2.2. Descripción de los datos
4.2.3. Características del análisis y resultados
4.2.4. Conclusiones
4.3. Modelos dinámicos para la predicción a corto plazo de (óV óe)
5. Variaciones geocéntricas causadas por el flujo de agua continental 101
5.1. Introducción
5.2. Descripción de los datos
5.3. Características del análisis y resultados
5.4. Conclusiones
6. Modelos espacio-temporales para el flujo de agua continental
6.1. Introducción
6.2. Descripción de datos
6.3. Características del análisis
6.4. Resultados
6.5. Conclusiones
7. Estudio armónico del exceso en la duración del día
7.1. Introducción
7.2. Descripción de los datos
7.3. Características del análisis y resultados
7.4. Conclusiones
8. Ruido
8.1. Tipología básica
8.2. Matrices de covarianza
8.2.1. Matriz de covarianzas para un ruido blanco
8.2.2. Matriz de covarianzas para un ruido parpadeante
8.2.3. Matriz de covarianzas para un paseo aleatorio
8.3. Relación ruido-periodograma
8.4. Ruido en las observaciones GPS
9. Algoritmo FHAST
9.1. Introducción
9.2. Función objetivo
9.3. Modelo estocástico
9.3.1. Estimación de un índice espectral
9.3.2. Componente residual como combinación de varios ruidos. Es-timación de la frecuencia de transición,
9.4. Modelo funcional
9.5. Estimación de la componente de varianza
9.5.1. Condición de no negatividad
9.6. Extensión del periodograma
9.6.1. Aceleración del cálculo del periodograma
9.7. Incertidumbre
9.7.1. Parámetros lineales y no lineales del modelo funcional
9.7.2. Parámetros del modelo estocástico
9.8. Criterios de parada algorítmica
9.9. Entramado algorítmico
9.10. Simulación
10.Estudio de las series de posiciones de estaciones GPS
10.1. Introducción
10.2. Análisis de las series temporales residuales
10.3. Resultados y discusión
10.4. Conclusiones
11.Conclusiones y perspectivas
11.1. Conclusiones
11.2. Perspectivas
II EXTENDED SUMMARY: NON-LINEAR HARMO NIC MODELS FOR GEODETIC TIME SERIES
S.1. Introduction
S.2. The signal detection problem
S.2.1. Definition of time series
S.2.2. Spectral analysis
S.2.3. The signal detection problem
S.3. Non-linear harmonic analysis
S.4. Celestial Pole Offsets
S.4.1. IAU1980 Pole Offsets
S.4.2. IAU2000 Pole Offsets
S.4.3. Dynamic models for (óV,óe) prediction
S.5. Geocenter variations caused by continental water flux
S.5.1. Introduction
S.5.2. Data
S.5.3. Analysis and results
S.5.4. Conclusions
S.6. Spatio-temporal models for continental water flux
S.6.1. Introduction
S.6.2. Data
S.6.3. Methods
S.6.4. Results
S.6.5. Conclusions
S.7. Harmonio study of the length of day
S.7.1. Introduction
S.7.2. Data
S.7.3. Analysis and results
S.7.4. Conclusions
S.8. Noise
S.8.1. Typology
S.8.2. Covariance matrices
S.8.3. Relationship noise-periodogram
S.8.4. Noise in GPS observations
S.9. FHAST algorithm
S.9.1. Introduction
S.9.2. Stochastic model
S.9.3. Functional model
S.9.4. Component variance estimation
S.9.5. Modification of the periodogram
S.9.6. Stop criteria
S9.7. Algorithm
S.10. Study of the position time series of GPS stations
S.10.1.Introduction
S.10.2. Analysis and results
S.10.S.Conclusions
S.11 Conclusions and outlook
S.11.1.Conclusions
S.11.2. Outlook
III APÉNDICES
A. Ley de propagación del error
B, Acrónimos, abreviaturas y unidades
C. Modelos armónicos no lineales de algunas estaciones GPS
BibliografíaNuméro de notice : 10519 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse française Note de thèse : Bibliographie nature-HAL : Thèse DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=45141 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 10519-01 30.60 Livre Centre de documentation Géodésie Disponible Effect of the satellite laser ranging network distribution on geocenter motion estimation / Xavier Collilieux in Journal of geophysical research : Solid Earth, Vol 114 n° B4 (April 2009)
[article]
Titre : Effect of the satellite laser ranging network distribution on geocenter motion estimation Type de document : Article/Communication Auteurs : Xavier Collilieux , Auteur ; Zuheir Altamimi , Auteur ; Jim Ray, Auteur ; X. Wu, Auteur Année de publication : 2009 Article en page(s) : 17 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] fonction de Green
[Termes IGN] géocentre
[Termes IGN] masse de la Terre
[Termes IGN] série temporelle
[Termes IGN] télémétrie laser sur satelliteRésumé : (auteur) SLR network translations estimated between a quasi-instantaneous station position set, theoretically expressed with respect to the center of mass of the Earth (CM), and a secular reference frame are the signature of the motion of the CM with respect to the Earth crust. Geocenter motion is defined here to be the motion of the CM with respect to the geometric center of the solid Earth surface (CF). SLR translational variations cannot be rigorously interpreted as identical to geocenter motion due to the sparse and nonuniform distribution of the SLR network. Their difference is called the network effect, which should be dominated at subdecadal timescales by loading signals.We have computed translation time series of the SLR network using two independent geophysically based loading models. One is a displacement model estimated from surface fluid data (Green’s function approach), called forward model, and the other is a displacement model estimated from GPS and ocean bottom pressure (OBP) data, called inverse model. The translation models have been subtracted from their respective geocenter motion models computed from degree-1 mass load coefficients in order to evaluate their network effect biases. Scatter due to the SLR network effect is at the level of 1.5 mm RMS. It could slightly shift the phase of the annual SLR geocenter motion estimate by less than 1 month and could affect X and Z annual geocenter motion amplitudes at the 1-mm level, which is about one third of the expected signal. Two distinct methods are suggested to account for network effect when comparing SLR translations to geocenter motion models. The first is to add the network effect term predicted by a displacement model to the geocenter motion loading model. The second relies on an adequate combination of SLR and GPS products to estimate SLR translation that could be better compared with geocenter motion. Numéro de notice : A2009-531 Affiliation des auteurs : IGN+Ext (1940-2011) Thématique : POSITIONNEMENT Nature : Article DOI : 10.1029/2008JB005727 Date de publication en ligne : 07/04/2009 En ligne : http://dx.doi.org/10.1029/2008JB005727 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83525
in Journal of geophysical research : Solid Earth > Vol 114 n° B4 (April 2009) . - 17 p.[article]Documents numériques
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Effect of the satellite laser ranging networkAdobe Acrobat PDF Zur Parametrisierung radialsymmetrischer Dichtemodelle für die Erde / H. Wziontek (2005)
Titre : Zur Parametrisierung radialsymmetrischer Dichtemodelle für die Erde Titre original : [Pour la paramétrisation de modèles denses symétriques pour la Terre] Type de document : Thèse/HDR Auteurs : H. Wziontek, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2005 Collection : DGK - C Sous-collection : Dissertationen num. 587 Importance : 102 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5026-6 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] croute terrestre
[Termes IGN] densité
[Termes IGN] équation de Poisson
[Termes IGN] masse de la Terre
[Termes IGN] potentiel de pesanteur terrestre
[Termes IGN] vitesseIndex. décimale : 30.40 Géodésie physique Résumé : (Auteur) Even in the frame of a spherical symmetric, non-rotating, linear elastic and isotropic model an independent description of the Earth's density and elastic properties, as usual in most existing models, has no unique solution and thus leads to an over-parametrisation. Whereas the elastic properties can be verified well with the help of seismic traveltimes, the density remains much less determinate. With this work, an adequate description of a normal density distribution based on a physically meaningful, non-empirical parametrisation and an abstraction to the essential physical properties will be presented. Beside the postulate on homogeneity of the chemical composition and phase inside each shell and an adiabatic gradient of temperature, the main assumption is hydrostatic equilibrium, which must be fulfilled in a global sense for the widest parts of the Earth's interior. Under these circumstances the Williamson-Adams-equation holds as a fundamental relation between density and seismic velocities. Deviations from the underlying suppositions can be described, if necessary and appropriate information exists, a priori by the Bullen-Parameter. By the physical relation between density and seismic velocities alone a parametrisation is not given. With the help of a postulate on a pressure-density-relation in historical density laws it is possible to develop a suitable function. A differential equation follows from the Poisson equation for the inner gravitational potential in conjunction with that postulate and the assumption of hydrostatic equilibrium. Its special solutions lead in consistence with seismic data to a parametrisation of the density. Extensive investigations show that only functions in even powers of the radius allow a best and stable fit to the seismic data, while ordinary polynomials most common in use are less eligible for a description of the density. Furthermore, to obtain a stable determination of the density a strict separation of the data-types is unavoidable. From the seismic velocities it is only possible to infer the shape of the density-function within the shells, additional data as the density below the crust-mantle-boundary, the geodetic values for mean mass and mean moment of inertia and the frequencies of the free oscillations are necessary to fix the absolute level in each shell. Under consideration of the aforementioned aspects it is possible to obtain a unique and stable description of a normal density distribution in accordance with seismic and geodetic information. Thus the presented parametrisation can serve as a basis for anomaly analysis in geodesy and geophysics. Numéro de notice : 13274 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54953 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13274-01 30.40 Livre Centre de documentation Géodésie Disponible 13274-02 30.40 Livre Centre de documentation Géodésie Disponible The effect on the geoid of lateral topographic density variations / Lard Erik Sjöberg in Journal of geodesy, vol 78 n° 1-2 (September 2004)
[article]
Titre : The effect on the geoid of lateral topographic density variations Type de document : Article/Communication Auteurs : Lard Erik Sjöberg, Auteur Année de publication : 2004 Article en page(s) : pp 34 - 39 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] anomalie de pesanteur
[Termes IGN] formule de Stokes
[Termes IGN] géoïde gravimétrique
[Termes IGN] levé gravimétrique
[Termes IGN] masse de la Terre
[Termes IGN] précision centimétrique
[Termes IGN] surface topographique
[Termes IGN] variation de densitéRésumé : (Auteur) Gravimetric geoid determination by Stokes' formula requires that the effects of topographic masses be removed prior to Stokes integration. This step includes the direct topographic and the downward continuation (DWC) effects on gravity anomaly, and the computations yield the co-geoid height. By adding the effect of restoration of the topography, the indirect effect on the geoid, the geoid height is obtained. Unfortunately, the computations of all these topographic effects are hampered by the uncertainty of the density distribution of the topography. Usually the computations are limited to a constant topographic density, but recently the effects of lateral density variations have been studied for their direct and indirect effects on the geoid. It is emphasised that the DWC effect might also be significantly affected by a lateral density variation. However, instead of computing separate effects of lateral density variation for direct, DWC and indirect effects, it is shown in two independent ways that the total geoid effect due to the lateral density anomaly can be represented as a simple correction proportional to the lateral density anomaly and the elevation squared of the computation point. This simple formula stems from the fact that the significant long-wavelength contributions to the various topographic effects cancel in their sum. Assuming that the lateral density anomaly is within 20% of the standard topographic density, the derived formula implies that the total effect on the geoid is significant at the centimetre level for topographic elevations above 0.66km. For elevations of 1000, 2000 and 5000 m the effect is within +2.2, +8.8 and +56.8 cm, respectively. For the elevation of Mt. Everest the effect is within + 1.78 m. Numéro de notice : A2004-381 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-003-0363-0 En ligne : https://doi.org/10.1007/s00190-003-0363-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26908
in Journal of geodesy > vol 78 n° 1-2 (September 2004) . - pp 34 - 39[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-04032 RAB Revue Centre de documentation En réserve L003 Disponible 266-04031 RAB Revue Centre de documentation En réserve L003 Disponible Origin of negative gravimetry anomaly landward of trench junction / Y. Tomoda in Proceedings of the Japan Academy, Series B, vol 79B n° 2 (01/02/2003)PermalinkDétermination des variations du géocentre / Patrick Sillard in Bulletin d'information de l'Institut géographique national, n° 69 (octobre 1998)PermalinkEine approximative Lösung der fixen gravimetrischen Randwertaufgabe im Innen- und Außenraum der Erde / J. Engels (1991)PermalinkMethods of tidal loading computation / Trevor Baker in Bulletin international des marées terrestres, n° 94 (juin 1985)Permalink3rd international symposium Geodesy and Physics of the Earth: Proceedings, 1. Volume 1 / H. Kautzleben (1976)Permalink3rd international symposium Geodesy and Physics of the Earth: Proceedings, 2. Volume 2 / H. Kautzleben (1976)PermalinkFormulation pratique du champ de gravite terrestre par les fonctions régionalisées / Jean Kovalevsky (1970)PermalinkSur une application de la Formule de Stokes à la recherche du géoïde mondial et du centre des masses de la Terre / Jean-Jacques Levallois (01/06/1967)PermalinkThe geoidal undulations and disturbing masses / L. Tanni (1951)Permalink