Descripteur
Documents disponibles dans cette catégorie (740)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
The combination of GNSS-levelling data and gravimetric (quasi-) geoid heights in the presence of noise / R. Klees in Journal of geodesy, vol 84 n° 12 (December 2010)
[article]
Titre : The combination of GNSS-levelling data and gravimetric (quasi-) geoid heights in the presence of noise Type de document : Article/Communication Auteurs : R. Klees, Auteur ; I. Prutkin, Auteur Année de publication : 2010 Article en page(s) : pp 731 - 749 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] altitude normale
[Termes IGN] altitude orthométrique
[Termes IGN] bruit (théorie du signal)
[Termes IGN] champ de pesanteur local
[Termes IGN] collocation par moindres carrés
[Termes IGN] données GNSS
[Termes IGN] géoïde gravimétrique
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] matrice de covariance
[Termes IGN] nivellement par GPS
[Termes IGN] problème des valeurs limites
[Termes IGN] Suisse
[Termes IGN] varianceRésumé : (Auteur) We propose a methodology for the combination of a gravimetric (quasi-) geoid with GNSS-levelling data in the presence of noise with correlations and/or spatially varying noise variances. It comprises two steps: first, a gravimetric (quasi-) geoid is computed using the available gravity data, which, in a second step, is improved using ellipsoidal heights at benchmarks provided by GNSS once they have become available. The methodology is an alternative to the integrated processing of all available data using least-squares techniques or least-squares collocation. Unlike the corrector-surface approach, the pursued approach guarantees that the corrections applied to the gravimetric (quasi-) geoid are consistent with the gravity anomaly data set. The methodology is applied to a data set comprising 109 gravimetric quasi-geoid heights, ellipsoidal heights and normal heights at benchmarks in Switzerland. Each data set is complemented by a full noise covariance matrix. We show that when neglecting noise correlations and/or spatially varying noise variances, errors up to 10% of the differences between geometric and gravimetric quasi-geoid heights are introduced. This suggests that if high-quality ellipsoidal heights at benchmarks are available and are used to compute an improved (quasi-) geoid, noise covariance matrices referring to the same datum should be used in the data processing whenever they are available. We compare the methodology with the corrector-surface approach using various corrector surface models. We show that the commonly used corrector surfaces fail to model the more complicated spatial patterns of differences between geometric and gravimetric quasi-geoid heights present in the data set. More flexible parametric models such as radial basis function approximations or minimum-curvature harmonic splines perform better. We also compare the proposed method with generalized least-squares collocation, which comprises a deterministic trend model, a random signal component and a random correlated noise component. Trend model parameters and signal covariance function parameters are estimated iteratively from the data using non-linear least-squares techniques. We show that the performance of generalized least-squares collocation is better than the performance of corrector surfaces, but the differences with respect to the proposed method are still significant. Numéro de notice : A2010-559 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0406-2 Date de publication en ligne : 29/08/2010 En ligne : https://doi.org/10.1007/s00190-010-0406-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30751
in Journal of geodesy > vol 84 n° 12 (December 2010) . - pp 731 - 749[article]Réservation
Réserver ce documentExemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 266-02010121 SL Revue Centre de documentation Revues en salle Disponible 266-2010121 SL Revue Centre de documentation Revues en salle Disponible A comparison of recent Earth gravitational models with emphasis on their contribution in refining the gravity and geoid at continental or regional scale / D. Arabelos in Journal of geodesy, vol 84 n° 11 (November 2010)
[article]
Titre : A comparison of recent Earth gravitational models with emphasis on their contribution in refining the gravity and geoid at continental or regional scale Type de document : Article/Communication Auteurs : D. Arabelos, Auteur ; C.C. Tscherning, Auteur Année de publication : 2010 Article en page(s) : pp 643 - 660 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse comparative
[Termes IGN] champ de pesanteur local
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] covariance
[Termes IGN] données GRACE
[Termes IGN] Earth Gravity Model 1996
[Termes IGN] Earth Gravity Model 2008
[Termes IGN] géoïde terrestreRésumé : (Auteur) Since the publication of the Earth gravitational model (EGM) 96 considerable improvements in the observation techniques resulted in the development of new improved models. The improvements are due to the availability of data from dedicated gravity mapping missions (CHAMP, GRACE) and to the use of 5? * 5? terrestrial and altimetry derived gravity anomalies. It is expected that the use of new EGMs will further contribute to the improvement of the resolution and accuracy of the gravity and geoid modeling in continental and regional scale. To prove this numerically, three representative Earth gravitational models are used for the reduction of several kinds of data related to the gravity field in different places of the Earth. The results of the reduction are discussed regarding the corresponding covariance functions which might be used for modeling using the least squares collocation method. The contribution of the EIGEN-GL04C model in most cases is comparable to that of EGM96. However, the big difference is shown in the case of EGM2008, due not only to its quality but obviously to its high degree of expansion. Almost in all cases the variance and the correlation length of the covariance functions of data reduced to this model up to its maximum degree are only a few percentages of corresponding quantities of the same data reduced up to degree 360. Furthermore, the mean value and the standard deviation of the reduced gravity anomalies in extended areas of the Earth such as Australia, Arctic region, Scandinavia or the Canadian plains, vary between -1 and +1 and between 5 and 10 * 10-5 ms-2, respectively, reflecting the homogenization of the gravity field on a regional scale. This is very important in using least squares collocation for regional applications. However, the distance to the first zero-value was in several cases much longer than warranted by the high degree of the expansion. This is attributed to errors of medium wavelengths stemming from the lack of, e.g., high-quality data in some area. Numéro de notice : A2010-476 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0397-z Date de publication en ligne : 15/09/2010 En ligne : https://doi.org/10.1007/s00190-010-0397-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30669
in Journal of geodesy > vol 84 n° 11 (November 2010) . - pp 643 - 660[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2010111 SL Revue Centre de documentation Revues en salle Disponible Combining EGM2008 and SRTM/DTM2006.0 residual terrain model data to improve quasigeoid computations in mountainous areas devoid of gravity data / C. Hirt in Journal of geodesy, vol 84 n° 9 (September 2010)
[article]
Titre : Combining EGM2008 and SRTM/DTM2006.0 residual terrain model data to improve quasigeoid computations in mountainous areas devoid of gravity data Type de document : Article/Communication Auteurs : C. Hirt, Auteur ; Will E. Featherstone, Auteur ; Urs Marti, Auteur Année de publication : 2010 Article en page(s) : pp 557 - 567 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Alpes
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] Earth Gravity Model 2008
[Termes IGN] géoïde terrestre
[Termes IGN] modèle de géopotentiel
[Termes IGN] modèle numérique de terrain
[Termes IGN] montagne
[Termes IGN] résiduRésumé : (Auteur) A global geopotential model, like EGM2008, is not capable of representing the high-frequency components of Earth’s gravity field. This is known as the omission error. In mountainous terrain, omission errors in EGM2008, even when expanded to degree 2,190, may reach amplitudes of 10 cm and more for height anomalies. The present paper proposes the utilisation of high-resolution residual terrain model (RTM) data for computing estimates of the omission error in rugged terrain. RTM elevations may be constructed as the difference between the SRTM (Shuttle Radar Topography Mission) elevation model and the DTM2006.0 spherical harmonic topographic expansion. Numerical tests, carried out in the German Alps with a precise gravimetric quasigeoid model (GCG05) and GPS/levelling data as references, demonstrate that RTM-based omission error estimates improve EGM2008 height anomaly differences by 10 cm in many cases. The comparisons of EGM2008-only height anomalies and the GCG05 model showed 3.7 cm standard deviation after a bias-fit. Applying RTM omission error estimates to EGM2008 reduces the standard deviation to 1.9 cm which equates to a significant improvement rate of 47%. Using GPS/levelling data strongly corroborates these findings with an improvement rate of 49%. The proposed RTM approach may be of practical value to improve quasigeoid determination in mountainous areas without sufficient regional gravity data coverage, e.g., in parts of Asia, South America or Africa. As a further application, RTM omission error estimates will allow refined validation of global gravity field models like EGM2008 from GPS/levelling data. Numéro de notice : A2010-415 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0395-1 Date de publication en ligne : 03/07/2010 En ligne : https://doi.org/10.1007/s00190-010-0395-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30608
in Journal of geodesy > vol 84 n° 9 (September 2010) . - pp 557 - 567[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2010091 SL Revue Centre de documentation Revues en salle Disponible Développement d’un système léger de gravimétrie mobile : LiMoG / José Cali in Revue des Systèmes (RS) - Instrumentation - Mesure - Métrologie (Série I2M), vol 10 n° 3-4 (Juillet - Décembre 2010)
[article]
Titre : Développement d’un système léger de gravimétrie mobile : LiMoG Type de document : Article/Communication Auteurs : José Cali, Auteur ; Bertrand de Saint-Jean , Auteur ; Jérome Verdun , Auteur ; Henri Duquenne (1948-2010) , Auteur Année de publication : 2010 Article en page(s) : pp 59 - 79 Note générale : bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] filtre de Kalman
[Termes IGN] géoïde local
[Termes IGN] geoïde marin
[Termes IGN] gravimètre absolu
[Termes IGN] gravimétrie mobile
[Termes IGN] levé gravimétrique
[Termes IGN] profil bathymétriqueRésumé : (auteur) L’objectif de cette étude est le développement d’un système de gravimétrie vectorielle permettant d’estimer les composantes du champ de pesanteur avec une exactitude de l’ordre du mGal et une résolution spatiale de quelques kilomètres. Ces mesures gravimétriques permettraient d’élaborer des modèles locaux de géoïde à haute résolution indispensables pour la détermination des altitudes à partir des techniques de positionnement GPS. Une campagne de mesure sur des profils marins de gravimétrie a permis de tester la chaîne de traitement des données issues du système LiMoG. L’estimation des perturbations du champ de pesanteur par un filtre de Kalman est basée sur la trajectoire réelle du système et des mesures accélérométriques simulées à partir de perturbations de pesanteur mesurées le long des profils marins de gravimétrie. Cet article décrit le système LiMoG et montre les résultats de ces simulations. Numéro de notice : A2010-630 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueNat DOI : 10.3166/i2m.10.59-79 En ligne : https://doi.org/10.3166/i2m.10.59-79 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97467
in Revue des Systèmes (RS) - Instrumentation - Mesure - Métrologie (Série I2M) > vol 10 n° 3-4 (Juillet - Décembre 2010) . - pp 59 - 79[article]Tuning a gravimetric quasigeoid to GPS-levelling by non-stationary least-squares collocation / N. Darbehesti in Journal of geodesy, vol 84 n° 7 (July 2010)
[article]
Titre : Tuning a gravimetric quasigeoid to GPS-levelling by non-stationary least-squares collocation Type de document : Article/Communication Auteurs : N. Darbehesti, Auteur ; Will E. Featherstone, Auteur Année de publication : 2010 Article en page(s) : pp 419 - 431 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] appariement de données localisées
[Termes IGN] collocation par moindres carrés
[Termes IGN] géoïde altimétrique
[Termes IGN] géoïde gravimétrique
[Termes IGN] géoïde local
[Termes IGN] nivellement par GPS
[Termes IGN] PerthRésumé : (Auteur) This paper addresses implementation issues in order to apply non-stationary least-squares collocation (LSC) to a practical geodetic problem: fitting a gravimetric quasigeoid to discrete geometric quasigeoid heights at a local scale. This yields a surface that is useful for direct GPS heighting. Non-stationary covariance functions and a non-stationary model of the mean were applied to residual gravimetric quasigeoid determination by planar LSC in the Perth region of Western Australia. The non-stationary model of the mean did not change the LSC results significantly. However, elliptical kernels in non-stationary covariance functions were used successfully to create an iterative optimisation loop to decrease the difference between the gravimetric quasigeoid and geometric quasigeoid at 99 GPS-levelling points to a user-prescribed tolerance. Numéro de notice : A2010-301 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0377-3 Date de publication en ligne : 18/04/2010 En ligne : https://doi.org/10.1007/s00190-010-0377-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30495
in Journal of geodesy > vol 84 n° 7 (July 2010) . - pp 419 - 431[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2010071 SL Revue Centre de documentation Revues en salle Disponible Assessing the accuracy of GEOID03 and GEOID09 in Connecticut / Thomas H. Meyer in SaLIS Surveying and land information science, vol 70 n° 2 (Summer 2010)PermalinkCan mean values of Helmert's gravity anomalies be continued downward directly? / Petr Vanicek in Geomatica, vol 64 n° 2 (June 2010)PermalinkMantle dynamics, geoid, inertia and TPW since 120 Myr / Hélène Rouby in Earth and planetary science letters, vol 292 n° 3-4 (April 2010)PermalinkEstablishment of an empirical Geoid Model for a small geographic area: a case study of Port Harcourt, Nigeria / J. Olaleye in SaLIS Surveying and land information science, vol 70 n° 1 (Spring 2010)PermalinkA bias-free geodetic boundary value problem approach to height datum unification / Alireza A. Ardalan in Journal of geodesy, vol 84 n° 2 (February 2010)PermalinkFinite element method for solving geodetic boundary value problems / Z. Faskova in Journal of geodesy, vol 84 n° 2 (February 2010)PermalinkFundamental gravity network of the Republic Croatia in the function of control and improving of national and European geoid model / I. Grgic (01/01/2010)PermalinkPreliminary works on creation of the new geoid model HRG2009 / I. Grgic (01/01/2010)PermalinkPermalinkSea surface topography and marine geoid by airborne laser altimetry and shipborne ultrasound altimetry / Philippe Limpach (2010)Permalink