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A bias-free geodetic boundary value problem approach to height datum unification / Alireza A. Ardalan in Journal of geodesy, vol 84 n° 2 (February 2010)
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[article]
Titre : A bias-free geodetic boundary value problem approach to height datum unification Type de document : Article/Communication Auteurs : Alireza A. Ardalan, Auteur ; R. Karimi, Auteur ; Markku Poutanen, Auteur Année de publication : 2010 Article en page(s) : pp 123 - 134 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] cote géopotentielle
[Termes IGN] erreur systématique
[Termes IGN] Finlande
[Termes IGN] géoïde local
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] problème des valeurs limites
[Termes IGN] réseau altimétrique local
[Termes IGN] système de référence altimétriqueRésumé : (Auteur) A geodetic boundary value problem (GBVP) approach has been formulated which can be used for solving the problem of height datum unification. The developed technique is applied to a test area in Southwest Finland with approximate size of 1.5° x 3° and the bias of the corresponding local height datum (local geoid) with respect to the geoid is computed. For this purpose the bias-free potential difference and gravity difference observations of the test area are used and the offset (bias) of the height datum, i.e., Finnish Height Datum 2000 (N2000) fixed to Normaal Amsterdams Peil (NAP) as origin point, with respect to the geoid is computed. The results of this computation show that potential of the origin point of N2000, i.e., NAP, is (62636857.68 1 0.5) (m2/s2) and as such is (0.191 1 0.003) (m) under the geoid defined by W 0 = 62636855.8 (m2/s2). As the validity test of our methodology, the test area is divided into two parts and the corresponding potential difference and gravity difference observations are introduced into our GBVP separately and the bias of height datums of the two parts are computed with respect to the geoid. Obtaining approximately the same bias values for the height datums of the two parts being part of one height datum with one origin point proves the validity of our approach. Besides, the latter test shows the capability of our methodology for patch-wise application. Copyright Springer Numéro de notice : A2010-107 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-009-0348-8 Date de publication en ligne : 10/10/2009 En ligne : https://doi.org/10.1007/s00190-009-0348-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30303
in Journal of geodesy > vol 84 n° 2 (February 2010) . - pp 123 - 134[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2010021 SL Revue Centre de documentation Revues en salle Disponible Finite element method for solving geodetic boundary value problems / Z. Faskova in Journal of geodesy, vol 84 n° 2 (February 2010)
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Titre : Finite element method for solving geodetic boundary value problems Type de document : Article/Communication Auteurs : Z. Faskova, Auteur ; Robert Cunderlik, Auteur ; Karol Mikula, Auteur Année de publication : 2010 Article en page(s) : pp 135 - 144 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] Earth Gravity Model 2008
[Termes IGN] géoïde
[Termes IGN] méthode des éléments finis
[Termes IGN] problème de Dirichlet
[Termes IGN] problème des valeurs limitesRésumé : (Auteur) The goal of this paper is to present the finite element scheme for solving the Earth potential problems in 3D domains above the Earth surface. To that goal we formulate the boundary-value problem (BVP) consisting of the Laplace equation outside the Earth accompanied by the Neumann as well as the Dirichlet boundary conditions (BC). The 3D computational domain consists of the bottom boundary in the form of a spherical approximation or real triangulation of the Earth’s surface on which surface gravity disturbances are given. We introduce additional upper (spherical) and side (planar and conical) boundaries where the Dirichlet BC is given. Solution of such elliptic BVP is understood in a weak sense, it always exists and is unique and can be efficiently found by the finite element method (FEM). We briefly present derivation of FEM for such type of problems including main discretization ideas. This method leads to a solution of the sparse symmetric linear systems which give the Earth’s potential solution in every discrete node of the 3D computational domain. In this point our method differs from other numerical approaches, e.g. boundary element method (BEM) where the potential is sought on a hypersurface only. We apply and test FEM in various situations. First, we compare the FEM solution with the known exact solution in case of homogeneous sphere. Then, we solve the geodetic BVP in continental scale using the DNSC08 data. We compare the results with the EGM2008 geopotential model. Finally, we study the precision of our solution by the GPS/levelling test in Slovakia where we use terrestrial gravimetric measurements as input data. All tests show qualitative and quantitative agreement with the given solutions. Copyright Springer Numéro de notice : A2010-108 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-009-0349-7 Date de publication en ligne : 13/10/2009 En ligne : https://doi.org/10.1007/s00190-009-0349-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30304
in Journal of geodesy > vol 84 n° 2 (February 2010) . - pp 135 - 144[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2010021 SL Revue Centre de documentation Revues en salle Disponible Impact of loading effects on determination of the International Terrestrial Reference Frame / Xavier Collilieux in Advances in space research, vol 45 n° 1 ([04/01/2010])
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Titre : Impact of loading effects on determination of the International Terrestrial Reference Frame Type de document : Article/Communication Auteurs : Xavier Collilieux , Auteur ; Zuheir Altamimi
, Auteur ; David Coulot
, Auteur ; Tonie M. van Dam, Auteur ; Jim Ray, Auteur
Année de publication : 2010 Article en page(s) : pp 144 - 154 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] effet de charge
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] modèle linéaire
[Termes IGN] série temporelleRésumé : (Auteur) The International Terrestrial Reference Frame (ITRF), as a realization of the International Terrestrial Reference System (ITRS), is represented by a set of station positions and linear velocities. They are intended to be used as regularized coordinates to which some corrections should be added to access instantaneous coordinates. The latest ITRS realization is the ITRF2005, which has integrated time series of station positions to form long-term solutions for the four space geodetic techniques. Currently, a purely linear model is used to parameterize station displacements in the estimation process, plus occasional discontinuities in case of earthquakes or equipment changes. However the input data have been derived without applying surface loading models and so surface loading effects are supposed to be embedded in the coordinates as measured quantities. We evaluate the effect of applying a posteriori loading corrections, which include the effect of atmospheric, non-tidal ocean, and continental water loading, to time series of positions estimated from Satellite Laser Ranging (SLR), Very Long Baseline Interferometry (VLBI), and Global Positioning System (GPS) data. We notice that they reduce about 50% or more of the annual signals in the translation and scale parameter time series of the SLR and VLBI techniques, except in SLR Z translation. In general, the estimated secular frame definition is negligibly affected and estimated positions and velocities are not significantly modified for stations that have accumulated a large number of observations. A multi-technique combination of such derived frames allows concluding that, for some cases, loading model corrections might degrade co-located station coordinates almost as much as they benefit them. However, most significant improvement of the estimated secular coordinates is observed for stations with less than 100 estimated positions as demonstrated with a multi-technique combination. Numéro de notice : A2010-640 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2009.08.024 Date de publication en ligne : 01/09/2009 En ligne : https://doi.org/10.1016/j.asr.2009.08.024 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90717
in Advances in space research > vol 45 n° 1 [04/01/2010] . - pp 144 - 154[article]Assessment of a numerical method for computing the spherical harmonic coefficients of the gravitational potential of a constant density polyhedron / Olivier Jamet (2010)
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contenu dans Gravity, Geoid and Earth Observation, IAG Commission 2 Gravity Field, Chania, Crete, Greece, 23-27 June 2008 / Stelios Mertikas (2010)
Titre : Assessment of a numerical method for computing the spherical harmonic coefficients of the gravitational potential of a constant density polyhedron Type de document : Article/Communication Auteurs : Olivier Jamet , Auteur ; Jérome Verdun
, Auteur ; Dimitrios Tsoulis, Auteur ; Nicolas Gonindard, Auteur
Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2010 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 135 Conférence : IAG 2008 Commission 2, Gravity, Geoid and Earth Observation GGEO 23/06/2008 27/06/2008 Chania Crète - Grèce Proceedings Springer Importance : pp 437 - 443 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] géodésie physique
[Termes IGN] harmonique sphérique
[Termes IGN] modèle de géopotentiel
[Termes IGN] polyèdreRésumé : (auteur) This study focuses on the assessment of a linear algorithm for computing the spherical harmonic coefficients of the gravitational potential of a constant density polyhedron. The ability to compute such an expansion would favor several applications, in particular in the field of the interpretation and assessment of GOCE gravitational models. The studied algorithm is the only known method that would achieve this computation at a computational cost depending linearly on the number of computed coefficients. We show that although this methods suffers from severe divergence issues, it could be applied to retrieve band-limited estimates of the potential generated by a constant density polyhedron. Numéro de notice : C2008-016 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : MATHEMATIQUE/POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.1007/978-3-642-10634-7_58 Date de publication en ligne : 26/10/2010 En ligne : https://doi.org/10.1007/978-3-642-10634-7_58 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90744 Estimation of crustal vertical movements with GPS in a geocentric frame, within the framework of the TIGA project / Alvaro Santamaria Gomez (2010)
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Titre : Estimation of crustal vertical movements with GPS in a geocentric frame, within the framework of the TIGA project Titre original : Estimation des mouvements verticaux de l'écorce terrestre par GPS dans un repère géocentrique, dans le cadre du projet TIGA Type de document : Thèse/HDR Auteurs : Alvaro Santamaria Gomez, Auteur ; Marie-Noëlle Bouin , Directeur de thèse ; Guy Wöppelmann
, Directeur de thèse
Editeur : Paris, Meudon et Nançay : Observatoire de Paris Année de publication : 2010 Importance : 225 p. Format : 21 x 30 cm Note générale : Bibliographie
Doctoral dissertation of the Observatoire de Paris, speciality Astronomy and Astrophysics, geodesy mention in Paris on October 11th 2010Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] déformation de la croute terrestre
[Termes IGN] géocentre
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] marégraphe
[Termes IGN] niveau moyen des mers
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par GPS
[Termes IGN] série temporelleIndex. décimale : THESE Thèses et HDR Résumé : (Auteur) Long-term sea-level variations are provided today only by tide gauge measurements. However, these variations are contaminated by vertical long-term movements of the Earth crust. In order to obtain absolute sea-level variations, vertical movements at tide gauges can be now monitored by GPS.
The research work carried out was centered around the methodological study to improve the estimation of vertical velocities of a global GPS network co-located with tide gauges. We devised an optimal distribution of GPS stations which greatly improved the processing performance. This original procedure also allowed us to extend the analyzed data period. We obtained and exported station positions, satellite orbits, Earth orientation parameters, and apparent geocenter motion estimates to be combined by the International GNSS Service (IGS). The coupled effect of periodic signals and discontinuities on the estimated velocities was highlighted, showing the need to estimate both parameters in a consistent and rigorous way. The realistic velocity uncertainties were analyzed in depth taking into account the time-correlated noise content in the data. The noise content analysis led to the confirmation that temporal correlation of homogeneously reprocessed time series is dependent on data epoch. This way, we demonstrated that noise content in long GPS time series is mainly driven by the noise level of older data. However, to get the smallest formal velocity uncertainty, we still needed to use all the data available. The estimated velocity uncertainty was shown to agree with velocity differences with respect to the incoming new terrestrial reference frame, the ITRF2008.Note de contenu : Introduction
PART I. CONTEXT
1. Coastal sea level change and vertical land movements
1.1. Sea level observations
1.2. Long-term sea level rise estimation
1.3. Vertical movements at tide gauges
2. International efforts to monitor tide gauge benchmarks
2.1. First steps
2.2. The TIGA Pilot Project.
2.3. The University of La Rochelle TIGA Analysis Center
PART II. METHODOLOGY
3. GPS processing strategy definition
3.1. Testing the antenna modeling impact.
3.2. Tropospheric modeling test
3.3. Sub-network distribution
3.4. Other changes
3.5. Summary
4. Combination and products.
4.1. ULR3 combination procedure
4.2. ULR4 combination procedure
4.3. Comparison between ULR3 and ULR4 combination procedures
4.4. Summary
5. Vertical velocity field estimation.
5.1. Offsets, discontinuities and outliers
5.2. Seasonal signals
5.3. Datum selection
5.4. Summary
6. Vertical velocity field uncertainty
6.1. Noise effect on velocity uncertainties
6.2. Noise analysis methodology
6.3. Noise analysis procedure
6.4. Stochastic noise model selection
6.5. Reference frame uncertainty
6.6. Summary
PART III. RESULTS
7. ULR4 products
7.1. Frame transformation parameters
7.2. Terrestrial frame
7.3. Earth orientation parameters
7.4. Orbits
7.5. Summary
8. Vertical velocity field.
8.1. Selection of the stations in the ULR4 velocity field
8.2. Comparison of ULR3 and ULR4 vertical velocity fields
8.3. Comparison with multi-technique vertical velocity fields
8.4. Comparison with the ITRF2008 vertical velocity field
8.5. Sea level application
8.6. Summary
Conclusion and perspectivesNuméro de notice : 10447 Affiliation des auteurs : LAREG (1991-2011) Thématique : POSITIONNEMENT Nature : Thèse française Note de thèse : Thèse de doctorat : Astronomie et astrophysique. Géodésie : Observatoire de Paris : 2010 Organisme de stage : LAREG (IGN) nature-HAL : Thèse DOI : sans En ligne : https://hal.science/tel-00686823 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=45140 Réservation
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