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Geodetic VLBI for precise orbit determination of Earth satellites: a simulation study / Grzegorz Klopotek in Journal of geodesy, vol 94 n° 6 (June 2020)  

Public [article]  inJournal of geodesy > vol 94 n° 6 (June 2020) Titre : Geodetic VLBI for precise orbit determination of Earth satellites: a simulation study Type de document : Article/Communication Auteurs : Grzegorz Klopotek, Auteur ; Thomas Hobiger, Auteur ; Rüdiger Haas, Auteur ; Toshimichi Otsubo, Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] constellation GNSS [Termes IGN] données Galileo [Termes IGN] données Lageos [Termes IGN] données VGOS [Termes IGN] géocentre [Termes IGN] interférométrie à très grande base [Termes IGN] méthode de Monte-Carlo [Termes IGN] orbitographie [Termes IGN] paramètres d'orientation de la Terre [Termes IGN] quasar [Termes IGN] rotation de la Terre Résumé : (auteur) Recent efforts of tracking low Earth orbit and medium Earth orbit (MEO) satellites using geodetic very long baseline interferometry (VLBI) raise questions on the potential of this novel observation concept for space geodesy. Therefore, we carry out extensive Monte Carlo simulations in order to investigate the feasibility of geodetic VLBI for precise orbit determination (POD) of MEO satellites and assess the impact of quality and quantity of satellite observations on the derived geodetic parameters. The MEO satellites are represented in our study by LAGEOS-1/-2 and a set of Galileo satellites. The concept is studied on the basis of 3-day solutions in which satellite observations are included into real schedules of the continuous geodetic VLBI campaign 2017 (CONT17) as well as simulated schedules concerning the next-generation VLBI system, known as the VLBI Global Observing System (VGOS). Our results indicate that geodetic VLBI can perform on a comparable level as other space-geodetic techniques concerning POD of MEO satellites. For an assumed satellite observation precision better than 14.1 mm (47 ps), an average 3D orbit precision of 2.0 cm and 6.3 cm is found for schedules including LAGEOS-1/-2 and Galileo satellites, respectively. Moreover, geocenter offsets, which were so far out of scope for the geodetic VLBI analysis, are close to the detection limit for the simulations concerning VGOS observations of Galileo satellites, with the potential to further enhance the results. Concerning the estimated satellite orbits, VGOS leads to an average precision improvement of 80% with respect to legacy VLBI. In absolute terms and for satellite observation precision of 14.1 mm (47 ps), this corresponds to an average value of 17 mm and 7 mm concerning the 3D orbit scatter and precision of geocenter components, respectively. As shown in this study, a poor satellite geometry can degrade the derived Earth rotation parameters and VLBI station positions, compared to the quasar-only reference schedules. Therefore, careful scheduling of both quasar and satellite observations should be performed in order to fully benefit from this novel observation concept. Numéro de notice : A2020-342 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01381-9 Date de publication en ligne : 11/06/2020 En ligne : https://doi.org/10.1007/s00190-020-01381-9 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95221 [article]

Real-time sea-level monitoring using Kalman filtering of GNSS-R data / Joakim Strandberg in GPS solutions, vol 23 n° 3 (July 2019)  

Public [article]  inGPS solutions > vol 23 n° 3 (July 2019) Titre : Real-time sea-level monitoring using Kalman filtering of GNSS-R data Type de document : Article/Communication Auteurs : Joakim Strandberg, Auteur ; Thomas Hobiger, Auteur ; Rüdiger Haas, Auteur Année de publication : 2019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] B-Spline [Termes IGN] déformation de la croute terrestre [Termes IGN] filtre de Kalman [Termes IGN] glace de mer [Termes IGN] marée terrestre [Termes IGN] niveau de la mer [Termes IGN] rapport signal sur bruit [Termes IGN] réflectométrie par GNSS [Termes IGN] surface de la mer [Termes IGN] temps réel [Vedettes matières IGN] Altimétrie Résumé : (auteur) Current GNSS-R (GNSS reflectometry) techniques for sea surface measurements require data collection over longer periods, limiting their usability for real-time applications. In this work, we present a new, alternative GNSS-R approach based on the unscented Kalman filter and the so-called inverse modeling approach. The new method makes use of a mathematical description that relates SNR (signal-to-noise ratio) variations to multipath effects and uses a B-spline formalism to obtain time series of reflector height. The presented algorithm can provide results in real time with a precision that is significantly better than spectral inversion methods and almost comparable to results from inverse modeling in post-processing mode. To verify the performance, the method has been tested at station GTGU at the Onsala Space Observatory, Sweden, and at the station SPBY in Spring Bay, Australia. The RMS (root mean square) error with respect to nearby tide gauge data was found to be 2.0 cm at GTGU and 4.8 cm at SPBY when evaluating the output corresponding to real-time analysis. The method can also be applied in post-processing, resulting in RMS errors of 1.5 cm and 3.3 cm for GTGU and SPBY, respectively. Finally, based on SNR data from GTGU, it is also shown that the Kalman filter approach is able to detect the presence of sea ice with a higher temporal resolution than the previous methods and traditional remote sensing techniques which monitor ice in coastal regions. Numéro de notice : A2019-198 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-019-0851-1 En ligne : https://doi.org/10.1007/s10291-019-0851-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92653 [article]

Geodetic VLBI with an artificial radio source on the Moon : a simulation study / Grzegorz Klopotek in Journal of geodesy, vol 92 n° 5 (May 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 5 (May 2018) . - pp 457 – 469 Titre : Geodetic VLBI with an artificial radio source on the Moon : a simulation study Type de document : Article/Communication Auteurs : Grzegorz Klopotek, Auteur ; Thomas Hobiger, Auteur ; Rüdiger Haas, Auteur Année de publication : 2018 Article en page(s) : pp 457 – 469 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] C++ [Termes IGN] émetteur [Termes IGN] interférométrie à très grande base [Termes IGN] Lune [Termes IGN] méthode de Monte-Carlo [Termes IGN] modèle de simulation [Termes IGN] modèle stochastique [Termes IGN] simulation Résumé : (Auteur) We perform extensive simulations in order to assess the accuracy with which the position of a radio transmitter on the surface of the Moon can be determined by geodetic VLBI. We study how the quality and quantity of geodetic VLBI observations influence these position estimates and investigate how observations of such near-field objects affect classical geodetic parameters like VLBI station coordinates and Earth rotation parameters. Our studies are based on today’s global geodetic VLBI schedules as well as on those designed for the next-generation geodetic VLBI system. We use Monte Carlo simulations including realistic stochastic models of troposphere, station clocks, and observational noise. Our results indicate that it is possible to position a radio transmitter on the Moon using today’s geodetic VLBI with a two-dimensional horizontal accuracy of better than one meter. Moreover, we show that the next-generation geodetic VLBI has the potential to improve the two-dimensional accuracy to better than 5 cm. Thus, our results lay the base for novel observing concepts to improve both lunar research and geodetic VLBI. Numéro de notice : A2018-149 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1072-4 Date de publication en ligne : 27/10/2017 En ligne : https://doi.org/10.1007/s00190-017-1072-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89760 [article]

Determination of the local tie vector between the VLBI and GNSS reference points at Onsala using GPS measurements / Tong Ning in Journal of geodesy, vol 89 n° 7 (July 2015)  

Public [article]  inJournal of geodesy > vol 89 n° 7 (July 2015) . - pp 711 - 723 Titre : Determination of the local tie vector between the VLBI and GNSS reference points at Onsala using GPS measurements Type de document : Article/Communication Auteurs : Tong Ning, Auteur ; Rüdiger Haas, Auteur ; Gunnar Elgered, Auteur Année de publication : 2015 Article en page(s) : pp 711 - 723 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] analyse comparative [Termes IGN] co-positionnement [Termes IGN] données GPS [Termes IGN] données ITGB [Termes IGN] écart type [Termes IGN] point de liaison (géodésie) [Termes IGN] point géodésique [Termes IGN] précision millimétrique [Termes IGN] Suède Résumé : (auteur) Two gimbal-mounted GNSS antennas were installed on each side of the radome-enclosed 20 m VLBI radio telescope at the Onsala Space Observatory. GPS data with a 1 Hz sampling rate were recorded for five semi-kinematic and four kinematic observing campaigns. These GPS data were analysed together with data from the IGS station ONSA with an in-house Matlab-based GPS software package, using the double-difference analysis strategy. The coordinates of the GNSS antennas on the telescope were estimated for different observation angles of the telescope, at specific epochs, and used to calculate the geodetic reference point of the telescope. The local tie vector between the VLBI and the ONSA GNSS reference points in a geocentric reference frame was hence obtained. The two different types of observing campaigns gave consistent results of the estimated local tie vector and the axis offset of the telescope. The estimated local tie vector obtained from all nine campaigns gave standard deviations of 1.5, 1.0, and 2.9 mm for the geocentric X, Y, and Z components, respectively. The result of the estimated axis offset of the VLBI telescope shows a difference of 0.3 mm, with a standard deviation of 1.9 mm, with respect to a reference value obtained by two local surveys carried out in 2002 and 2008. Our results show that the presented method can be used as a complement to the more accurate but more labour intensive classical geodetic surveys to continuously monitor the local tie at co-location stations with an accuracy of a few millimetres Numéro de notice : A2015-355 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0809-1 Date de publication en ligne : 05/04/2015 En ligne : https://doi.org/10.1007/s00190-015-0809-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76778 [article]

Resolution on the nomenclature of space geodetic reference points and local tie measurements / Sten Bergstrand (nov 2014)    

Public Titre : Resolution on the nomenclature of space geodetic reference points and local tie measurements Type de document : Article/Communication Auteurs : Sten Bergstrand, Auteur ; Xavier Collilieux , Auteur ; John Dawson, Auteur ; Rüdiger Haas, Auteur ; Jim Long, Auteur ; Erricos C. Pavlis, Auteur ; Jérôme Saunier , Auteur ; Axel Nothnagel, Auteur Editeur : [s.l.] : [s.n.] Année de publication : nov 2014 Conférence : REFAG 2014, Reference Frames for Applications in Geosciences (IAG 2014 - Commission 1 symposium) 13/10/2014 17/10/2014 Kirchberg Grand Duché du Luxembourg Proceedings Springer Importance : 4 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] point de liaison (géodésie) [Termes IGN] point de repère [Termes IGN] terminologie Résumé : (auteur) We establish a specific but general terminology in order to clarify discussions on topics related to local tie measurements. The terminology meets the requirements of an observing system that encompasses existing International Earth Rotation and Reference Systems Service (IERS) techniques as well as other observation techniques of the Global Geodetic Observing System (GGOS). Numéro de notice : C2014-031 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans En ligne : https://www.iers.org/SharedDocs/Publikationen/EN/IERS/WorkingGroups/SiteSurvey/B [...] Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83276

Documents numériques

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Automated and continual determination of radio telescope reference points with sub-mm accuracy: results from a campaign at the Onsala Space Observatory / Michael Lösler in Journal of geodesy, vol 87 n° 8 (August 2013)  

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Multi-technique comparison of tropospheric zenith delays derived during the CONT02 campaign / Pascal Willis in Journal of geodesy, vol 79 n° 10-11 (February 2006)  

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Untersuchungen zu Erddeformationsmodellen für die Auswertung von geodätischen VLBI-Messungen / Rüdiger Haas (1996)

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