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Is the Jason-2 DORIS oscillator also affected by the South Atlantic Anomaly? / Pascal Willis in Advances in space research, vol 58 n° 12 (15 December 2016)
[article]
Titre : Is the Jason-2 DORIS oscillator also affected by the South Atlantic Anomaly? Type de document : Article/Communication Auteurs : Pascal Willis , Auteur ; Michael B. Heflin, Auteur ; Bruce J. Haines, Auteur ; Yoaz E. Bar-Sever, Auteur ; Willy I. Bertiger, Auteur ; Mioara Mandea, Auteur Année de publication : 2016 Article en page(s) : pp 2617 - 2627 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] anomalie de Bouguer
[Termes IGN] Atlantique Sud
[Termes IGN] co-positionnement
[Termes IGN] données DORIS
[Termes IGN] données GPS
[Termes IGN] erreur systématique
[Termes IGN] Jason
[Termes IGN] oscillateur
[Termes IGN] positionnement ponctuel précis
[Termes IGN] résidu
[Termes IGN] série temporelle
[Termes IGN] station permanenteRésumé : (auteur) We analyzed time series of daily DORIS and GPS station coordinate estimates derived from Precise Point Positioning (PPP). The DORIS coordinates were estimated using Jason-2 precise orbits based on GPS data only, implying that the station positions from the two techniques are expressed in the same GPS-based terrestrial reference frame. Comparisons of 3-D vectors of such co-located stations show systematic biases in position around South America when compared to local geodetic ties. We conclude that these results could be explained by a sensitivity of the Jason-2/DORIS oscillator to radiation when the satellite passes over the South Atlantic Anomaly (SAA). The effect for Jason-2 manifests mainly as an offset in station coordinates, though there is also evidence of a drift at the start of the mission that diminishes in time. This contrasts with the experience on Jason-1, wherein large, persistent drifts were observed for stations in this same (SAA) region. The spurious drift is much (∼90%) smaller for Jason-2, which may be attributable to the steps taken prior to launch to harden the oscillator. Analysis of DORIS Doppler residuals may indicate some small degradation after 2009 for these stations. Numéro de notice : A2016--178 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.09.015 Date de publication en ligne : 21/09/2016 En ligne : https://doi.org/10.1016/j.asr.2016.09.015 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91806
in Advances in space research > vol 58 n° 12 (15 December 2016) . - pp 2617 - 2627[article]Multi-technique comparison of atmospheric parameters at the DORIS co-location sites during CONT14 / Robert Heinkelmann in Advances in space research, vol 58 n° 12 (15 December 2016)
[article]
Titre : Multi-technique comparison of atmospheric parameters at the DORIS co-location sites during CONT14 Type de document : Article/Communication Auteurs : Robert Heinkelmann, Auteur ; Pascal Willis , Auteur ; Zhiguo Deng, Auteur ; Galina Dick, Auteur ; Tobias Nilsson, Auteur ; Benedikt Soja, Auteur ; Florian Zus, Auteur ; Jens Wickert, Auteur ; Harald Schuh, Auteur Année de publication : 2016 Article en page(s) : pp 2758 - 2773 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] analyse comparative
[Termes IGN] antenne DORIS
[Termes IGN] co-positionnement
[Termes IGN] modèle météorologique
[Termes IGN] retard troposphérique zénithal
[Termes IGN] station permanenteRésumé : (auteur) The atmospheric parameters, zenith delays and gradients, obtained by the DORIS, GPS, VLBI, and numerical weather models, ECMWF and NCEP, are compared at five DORIS co-located sites during the 15 days of the CONT14 campaign from 2014-05-06 until 2014-05-20. Further examined are two different solutions of GPS, VLBI and NCEP: for GPS, a network solution comparable to the TIGA reprocessing analysis strategy and a precise point positioning solution, for VLBI, a least squares and a Kalman filtered and smoothed solution, and for NCEP two spatial resolutions, 0.5° and 1.0°, are tested. The different positions of the antenna reference points at co-location sites affect the atmospheric parameters and have to be considered prior to the comparison. We assess and discuss these differences, tropospheric ties, by comparing ray-traced atmospheric parameters obtained at the positions of the various antenna reference points. While ray-traced ZHD and ZWD at the co-located antennas significantly differ, the ray-traced gradients show only very small differences. Weather events can introduce larger disagreement between atmospheric parameters obtained at co-location sites. The various weather model solutions in general agree very well in providing tropospheric ties. The atmospheric parameters are compared using statistical methods, such as the mean difference and standard deviations with repect to a weighted mean value. While GPS and VLBI atmospheric parameters agree very well in general, the DORIS observations are in several cases not dense enough to achieve a comparable level of agreement. The estimated zenith delays from DORIS, however, are competitive with the other space geodetic techniques. If the DORIS observation geometry is insufficient for the estimation of an atmospheric gradient, less than three satellites observed during the definition interval, the DORIS atmospheric parameters degrade and show small quasi-periodic variations that correlate with the number of observations and in particular with the number of satellites. An increase in the DORIS constellation concerning more satellites and in general more observations is very likely to significantly improve the quality of DORIS derived atmospheric parameters. For the first time, we tested a 6 h sampling of the DORIS gradients. Where the observations are sufficiently dense, the increased sampling results in an improvement of the agreement of the DORIS gradients with the other solutions. Numéro de notice : A2016--184 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.09.023 Date de publication en ligne : 29/09/2016 En ligne : https://doi.org/10.1016/j.asr.2016.09.023 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91819
in Advances in space research > vol 58 n° 12 (15 December 2016) . - pp 2758 - 2773[article]Determination of a terrestrial reference frame via Kalman filtering of very long baseline interferometry data / Benedikt Soja in Journal of geodesy, vol 90 n° 12 (December 2016)
[article]
Titre : Determination of a terrestrial reference frame via Kalman filtering of very long baseline interferometry data Type de document : Article/Communication Auteurs : Benedikt Soja, Auteur ; Tobias Nilsson, Auteur ; Kyriakos Balidakis, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 1311 - 1327 Note générale : Bibliographie ; Erratum : voir pdf Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] bruit (théorie du signal)
[Termes IGN] coordonnées géographiques
[Termes IGN] filtre de Kalman
[Termes IGN] image radar moirée
[Termes IGN] interférométrie à très grande base
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] modèle stochastique
[Termes IGN] station permanenteRésumé : (Auteur) Terrestrial reference frames (TRF), such as the ITRF2008, are primary products of geodesy. In this paper, we present TRF solutions based on Kalman filtering of very long baseline interferometry (VLBI) data, for which we estimate steady station coordinates over more than 30 years that are updated for every single VLBI session. By applying different levels of process noise, non-linear signals, such as seasonal and seismic effects, are taken into account. The corresponding stochastic model is derived site-dependent from geophysical loading deformation time series and is adapted during periods of post-seismic deformations. Our results demonstrate that the choice of stochastic process has a much smaller impact on the coordinate time series and velocities than the overall noise level. If process noise is applied, tests with and without additionally estimating seasonal signals indicate no difference between the resulting coordinate time series for periods when observational data are available. In a comparison with epoch reference frames, the Kalman filter solutions provide better short-term stability. Furthermore, we find out that the Kalman filter solutions are of similar quality when compared to a consistent least-squares solution, however, with the enhanced attribute of being easier to update as, for instance, in a post-earthquake period. Numéro de notice : A2016-804 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0924-7 En ligne : http://dx.doi.org/10.1007/s00190-016-0924-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82591
in Journal of geodesy > vol 90 n° 12 (December 2016) . - pp 1311 - 1327[article]Verification of the polish geodetic reference frame by means of a new solution based on permanent GNSS data from the years 2011-2014 / Tomasz Liwosz in Reports on geodesy and geoinformatics, vol 102 n° 1 (December 2016)
[article]
Titre : Verification of the polish geodetic reference frame by means of a new solution based on permanent GNSS data from the years 2011-2014 Type de document : Article/Communication Auteurs : Tomasz Liwosz, Auteur ; M. Ryczywolski, Auteur Année de publication : 2016 Article en page(s) : pp 52 - 66 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] Bernese
[Termes IGN] coordonnées GNSS
[Termes IGN] European Terrestrial Reference Frame
[Termes IGN] Pologne
[Termes IGN] repère de référence
[Termes IGN] réseau de premier ordre
[Termes IGN] station permanenteRésumé : (Auteur) The new solution for the Polish geodetic primary GNSS network was created to verify the currently used reference frame (PL-ETRF2000). The new solution is based on more GNSS data (more daily observation sessions included, a longer data timespan, GLONASS observations added) which were processed in a newer reference frame (IGb08) according to up-to-date methodology and using the latest version of Bernese GNSS Software. The new long-term solution (spanning 3.7 years) was aligned to the IGb08 reference frame using a minimum constraints approach. We categorized Polish reference stations into two categories according to their data length. We obtained good agreement of the new solution with the PL-ETRF2000: for most stations position differences did not exceed 5 mm in horizontal, and 10 mm in vertical components. However, for 30 stations we observed discontinuities in position time series, mostly due to GNSS equipment changes, which occured after the introduction of PL-ETRF2000. Position changes due to the discontinuities reached 9.1 mm in horizontal components, and 26.9 mm in vertical components. The new solution takes into account position discontinuities, and in addition also includes six new stations which were installed after the introduction of the PL-ETRF2000. Therefore, we propose to update the currently-used reference frame for the Polish geodetic primary network (PL-ETRF2000) with the new solution. The new solution was also accepted by the EUREF Technical Working Group as a class A solution (highest accuracy) according to EUREF standards. Numéro de notice : A2017-302 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/rgg-2016-0027 En ligne : https://doi.org/10.1515/rgg-2016-0027 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85337
in Reports on geodesy and geoinformatics > vol 102 n° 1 (December 2016) . - pp 52 - 66[article]A geometry-free and ionosphere-free multipath mitigation method for BDS three-frequency ambiguity resolution / Dezhong Chen in Journal of geodesy, vol 90 n° 8 (August 2016)
[article]
Titre : A geometry-free and ionosphere-free multipath mitigation method for BDS three-frequency ambiguity resolution Type de document : Article/Communication Auteurs : Dezhong Chen, Auteur ; Shirong Ye, Auteur ; Jingchao Xia, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 703 – 714 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] correction du trajet multiple
[Termes IGN] erreur systématique
[Termes IGN] positionnement par BeiDou
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal BeiDou
[Termes IGN] station de référence
[Termes IGN] trajet multiple
[Termes IGN] troposphèreRésumé : (auteur) Because of the unknown systematic errors and special satellite constellations in the Beidou system (BDS), it is difficult to quickly and reliably determine the ambiguity over long-range baselines in continuously operating reference station (CORS) network. This study seeks to improve the effectiveness and reliability of BDS ambiguity resolution (AR) by combining the geometry-free and ionosphere-free (GFIF) combination and multipath mitigation algorithm. The GFIF combination composed with three-frequency signals is free of distance-dependent errors and can be used to determine the narrow lane ambiguity. The presence of multipath errors means that not all ambiguities can be correctly achieved by rounding the averaged GFIF ambiguity series. A multipath model of the single-differenced (SD) GFIF combination from the previous period is established for each individual satellite. This model is subtracted from the SD GFIF combination for the current day to remove the effects of multipath errors. Using three triangle networks with lengths of approximately 120, 80 and 50 km, we demonstrate that the proposed method improves the AR performance. The ambiguity averaged first fixing time is typically less than 1801 s for inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO) satellites and less than 2007 s for the ∼42∘ elevation geostationary earth orbit (GEO) C02 satellite. However, it is more time consuming for the low-elevation GEO satellites C04 (∼18∘) and C05 (∼28∘). Kalman filtering is used to estimate the troposphere delays and two unfixed ambiguities by employing the ionosphere-free observations of all ambiguity-fixed/unfixed satellites. The experimental results show that only tens of seconds are required for AR in around 90 km baselines. Numéro de notice : A2016-503 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0903-z En ligne : http://dx.doi.org/10.1007/s00190-016-0903-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81527
in Journal of geodesy > vol 90 n° 8 (August 2016) . - pp 703 – 714[article]PermalinkAssessment of continental hydrosphere loading using GNSS measurements / Michał Zygmunt in Reports on geodesy and geoinformatics, vol 101 (June 2016)PermalinkTesting impact of the strategy of VLBI data analysis on the estimation of Earth Orientation Parameters and station coordinates / Agata Wielgosz in Reports on geodesy and geoinformatics, vol 101 (June 2016)PermalinkEvaluating the use of GPS heights in water conservation applications / Ahmed F. Elaksher in Survey review, vol 48 n° 348 (May 2016)PermalinkShort-term and long-term variability of antenna position due to thermal bending of pillar monument at permanent GNSS station / Lubomira Gerhatova in Reports on geodesy and geoinformatics, vol 100 (May 2016)PermalinkTowards reliable velocities of permanent GNSS stations / Janusz Bogusz in Reports on geodesy and geoinformatics, vol 100 (May 2016)PermalinkThe study of seasonal changes of permanent stations coordinates based on weekly EPN solutions / Kamil Maciuk in Artificial satellites, vol 51 n° 1 (March 2016)PermalinkArta geophysical observatory (Republic of Djibouti) ITRF local tie survey, version 1 / Jean-Claude Poyard (2016)PermalinkPermalinkSpécifications d’intégration d’une station GNSS permanente dans le RGP, version 2 / Sébastien Saur (2016)Permalink