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Exemplaires(1)
Code-barres | Cote | Support | Localisation | Section | Disponibilité |
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266-2014051 | SL | Revue | Centre de documentation | Revues en salle | Disponible |
Dépouillements


New VLBI2010 scheduling strategies and implications on the terrestrial reference frames / Jing Sun in Journal of geodesy, vol 88 n° 5 (May 2014)
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[article]
Titre : New VLBI2010 scheduling strategies and implications on the terrestrial reference frames Type de document : Article/Communication Auteurs : Jing Sun, Auteur ; Johannes Böhm , Auteur ; Tobias Nilsson, Auteur ; Hana Krásná, Auteur ; Sigrid Böhm, Auteur ; Harald Schuh, Auteur
Année de publication : 2014 Article en page(s) : pp 449 - 461 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] données ITGB
[Termes IGN] données VGOS
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] méthode de Monte-CarloRésumé : (Auteur) In connection with the work for the next generation VLBI2010 Global Observing System (VGOS) of the International VLBI Service for Geodesy and Astrometry, a new scheduling package (Vie_Sched) has been developed at the Vienna University of Technology as a part of the Vienna VLBI Software. In addition to the classical station-based approach it is equipped with a new scheduling strategy based on the radio sources to be observed. We introduce different configurations of source-based scheduling options and investigate the implications on present and future VLBI2010 geodetic schedules. By comparison to existing VLBI schedules of the continuous campaign CONT11, we find that the source-based approach with two sources has a performance similar to the station-based approach in terms of number of observations, sky coverage, and geodetic parameters. For an artificial 16 station VLBI2010 network, the source-based approach with four sources provides an improved distribution of source observations on the celestial sphere. Monte Carlo simulations yield slightly better repeatabilities of station coordinates with the source-based approach with two sources or four sources than the classical strategy. The new VLBI scheduling software with its alternative scheduling strategy offers a promising option with respect to applications of the VGOS. Numéro de notice : A2014-254 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0697-9 Date de publication en ligne : 12/02/2014 En ligne : https://doi.org/10.1007/s00190-014-0697-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33157
in Journal of geodesy > vol 88 n° 5 (May 2014) . - pp 449 - 461[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2014051 SL Revue Centre de documentation Revues en salle Disponible Application of SWACI products as ionospheric correction for single-point positioning: a comparative study / David Minkwitz in Journal of geodesy, vol 88 n° 5 (May 2014)
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[article]
Titre : Application of SWACI products as ionospheric correction for single-point positioning: a comparative study Type de document : Article/Communication Auteurs : David Minkwitz, Auteur ; Tajana Gerzen, Auteur ; Volker Wilken, Auteur ; Norbert Jakowski, Auteur Année de publication : 2014 Article en page(s) : pp 463 - 478 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] correction ionosphérique
[Termes IGN] dégradation du signal
[Termes IGN] ionosphère
[Termes IGN] positionnement par GNSS
[Termes IGN] précision du positionnement
[Termes IGN] teneur totale en électrons
[Termes IGN] traitement de données GNSSRésumé : (Auteur) In Global Navigation Satellite Systems (GNSS) using L-band frequencies, the ionosphere causes signal delays that correspond with link related range errors of up to 100 m. In a first order approximation the range error is proportional to the total electron content (TEC) of the ionosphere. Whereas this first order range error can be corrected in dual-frequency measurements by a linear combination of carrier phase- or code-ranges of both frequencies, single-frequency users need additional information to mitigate the ionospheric error. This information can be provided by TEC maps deduced from corresponding GNSS measurements or by ionospheric models. In this paper we discuss and compare different ionospheric correction methods for single-frequency users. The focus is on the comparison of the positioning quality using dual-frequency measurements, the Klobuchar model, the NeQuick model, the IGS TEC maps, the Neustrelitz TEC Model (NTCM-GL) and the reconstructed NTCM-GL TEC maps both provided via the ionosphere data service SWACI (http://swaciweb.dlr.de) in near real-time. For that purpose, data from different locations covering several days in 2011 and 2012 are investigated, including periods of quiet and disturbed ionospheric conditions. In applying the NTCM-GL based corrections instead of the Klobuchar model, positioning accuracy improvements up to several meters have been found for the European region in dependence on the ionospheric conditions. Further in mid- and low-latitudes the NTCM-GL model provides results comparable to NeQuick during the considered time periods. Moreover, in regions with a dense GNSS ground station network the reconstructed NTCM-GL TEC maps are partly at the same level as the final IGS TEC maps. Numéro de notice : A2014-255 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0698-8 Date de publication en ligne : 21/02/2014 En ligne : https://doi.org/10.1007/s00190-014-0698-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33158
in Journal of geodesy > vol 88 n° 5 (May 2014) . - pp 463 - 478[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2014051 SL Revue Centre de documentation Revues en salle Disponible Generalized integer aperture estimation for partial GNSS ambiguity fixing / Andreas Brack in Journal of geodesy, vol 88 n° 5 (May 2014)
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[article]
Titre : Generalized integer aperture estimation for partial GNSS ambiguity fixing Type de document : Article/Communication Auteurs : Andreas Brack, Auteur ; Christophe Günther, Auteur Année de publication : 2014 Article en page(s) : pp 479 - 490 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] compensation Lambda
[Termes IGN] double différence
[Termes IGN] mesurage de phase
[Termes IGN] positionnement par GNSS
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal Galileo
[Termes IGN] traitement de données GNSSRésumé : (Auteur) In satellite navigation, the key to high precision is to make use of the carrier-phase measurements. The periodicity of the carrier-phase, however, leads to integer ambiguities. Often, resolving the full set of ambiguities cannot be accomplished for a given reliability constraint. In that case, it can be useful to resolve a subset of ambiguities. The selection of the subset should be based not only on the stochastic system model but also on the actual measurements from the tracking loops. This paper presents a solution to the problem of joint subset selection and ambiguity resolution. The proposed method can be interpreted as a generalized version of the class of integer aperture estimators. Two specific realizations of this new class of estimators are presented, based on different acceptance tests. Their computation requires only a single tree search, and can be efficiently implemented, e.g., in the framework of the well-known LAMBDA method. Numerical simulations with double difference measurements based on Galileo E1 signals are used to evaluate the performance of the introduced estimation schemes under a given reliability constraint. The results show a clear gain of partial fixing in terms of the probability of correct ambiguity resolution, leading to improved baseline estimates. Numéro de notice : A2014-256 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0699-7 Date de publication en ligne : 18/02/2014 En ligne : https://doi.org/10.1007/s00190-014-0699-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33159
in Journal of geodesy > vol 88 n° 5 (May 2014) . - pp 479 - 490[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2014051 SL Revue Centre de documentation Revues en salle Disponible Earth orientation parameters estimated from VLBI during the CONT11 campaign / Tobias Nilsson in Journal of geodesy, vol 88 n° 5 (May 2014)
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[article]
Titre : Earth orientation parameters estimated from VLBI during the CONT11 campaign Type de document : Article/Communication Auteurs : Tobias Nilsson, Auteur ; Robert Heinkelmann, Auteur ; Maria Karbon, Auteur ; Virginia Raposo-Pulibo, Auteur ; Harald Schuh, Auteur Année de publication : 2014 Article en page(s) : pp 491 - 491 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données ITGB
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] orientation de la Terre
[Termes IGN] positionnement par ITGB
[Termes IGN] série temporelleRésumé : (Auteur) In this paper, we investigate the accuracy of the earth orientation parameters (EOP) estimated from the continuous VLBI campaign CONT11. We first estimated EOP with daily resolution and compared these to EOP estimated from GNSS data. We find that the WRMS differences are about 31 u as for polar motion and 7 u s for length of day. This is about the precision we could expect, based on Monte Carlo simulations and the results of the previous CONT campaigns. We also estimated EOP with hourly resolution to study the sub-diurnal variations. The results confirm the results of previous studies, showing that the current IERS model for high-frequency EOP variations does not explain all the sub-diurnal variations seen in the estimated time series. We then compared our results to various empirical high-frequency EOP models. However, we did not find that any of these gave any unambiguous improvement. Several simulations testing the impact of various aspects of, e.g. the observing network were also made. For example, we made simulations assuming that all CONT11 stations were equipped with fast VLBI2010 antennas. We found that the WRMS error decreased by about a factor five compared to the current VLBI system. Furthermore, the simulations showed that it is very important to have a homogenous global distribution of the stations for achieving the highest precision for the EOP. Numéro de notice : A2014-257 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0700-5 Date de publication en ligne : 21/02/2014 En ligne : https://doi.org/10.1007/s00190-014-0700-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33160
in Journal of geodesy > vol 88 n° 5 (May 2014) . - pp 491 - 491[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2014051 SL Revue Centre de documentation Revues en salle Disponible Comparisons of atmospheric mass variations derived from ECMWF reanalysis and operational fields, over 2003–2011 / E. Forootan in Journal of geodesy, vol 88 n° 5 (May 2014)
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[article]
Titre : Comparisons of atmospheric mass variations derived from ECMWF reanalysis and operational fields, over 2003–2011 Type de document : Article/Communication Auteurs : E. Forootan, Auteur ; Olga Didova, Auteur ; M. Schumacher, Auteur ; J. Kusche, Auteur ; B. Elsaka, Auteur Année de publication : 2014 Article en page(s) : pp 503 - 514 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] analyse diachronique
[Termes IGN] atmosphère terrestre
[Termes IGN] données GRACE
[Termes IGN] levé gravimétrique
[Termes IGN] masse d'air
[Termes IGN] variationRésumé : (Auteur) There are two spurious jumps in the atmospheric part of the Gravity Recovery and Climate Experiment-Atmosphere and Ocean De-aliasing level 1B (GRACE-AOD1B) products, which occurred in January-February of the years 2006 and 2010, as a result of the vertical level and horizontal resolution changes in the ECMWFop (European Centre for Medium-Range Weather Forecasts operational analysis). These jumps cause a systematic error in the estimation of mass changes from GRACE time-variable level 2 products, since GRACE-AOD1B mass variations are removed during the computation of GRACE level 2. In this short note, the potential impact of using an improved set of 6-hourly atmospheric de-aliasing products on the computations of linear trends as well as the amplitude of annual and semi-annual mass changes from GRACE is assessed. These improvements result from 1) employing a modified 3D integration approach (ITG3D), and 2) using long-term consistent atmospheric fields from the ECMWF reanalysis (ERA-Interim). The monthly averages of the new ITG3D-ERA-Interim de-aliasing products are then compared to the atmospheric part of GRACE-AOD1B, covering January 2003 to December 2010. These comparisons include the 33 world largest river basins along with Greenland and Antarctica ice sheets. The results indicate a considerable difference in total atmospheric mass derived from the two products over some of the mentioned regions. We suggest that future GRACE studies consider these through updating uncertainty budgets or by applying corrections to estimated trends and amplitudes/phases Numéro de notice : A2014-258 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0696-x Date de publication en ligne : 07/02/2014 En ligne : https://doi.org/10.1007/s00190-014-0696-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33161
in Journal of geodesy > vol 88 n° 5 (May 2014) . - pp 503 - 514[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 266-2014051 SL Revue Centre de documentation Revues en salle Disponible