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Influence of subdaily model for polar motion on the estimated GPS satellite orbits / Natalia Panafidina in Journal of geodesy, vol 93 n° 2 (February 2019)  

Public [article]  inJournal of geodesy > vol 93 n° 2 (February 2019) . - pp 229 - 240 Titre : Influence of subdaily model for polar motion on the estimated GPS satellite orbits Type de document : Article/Communication Auteurs : Natalia Panafidina, Auteur ; Urs Hugentobler, Auteur ; Manuela Seitz, Auteur Année de publication : 2019 Article en page(s) : pp 229 - 240 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse diachronique [Termes IGN] élément orbital [Termes IGN] erreur systématique [Termes IGN] International Terrestrial Reference Frame [Termes IGN] marée océanique [Termes IGN] mouvement du géocentre [Termes IGN] mouvement du pôle [Termes IGN] orbite [Termes IGN] positionnement par GPS [Termes IGN] rotation de la Terre [Termes IGN] satellite GPS [Termes IGN] traitement du signal Résumé : (auteur) In this contribution, it is shown that GPS orbits are able to absorb some diurnal signals in polar motion. The arising implications for the influence of the subdaily pole model on GPS solutions are discussed. Two signals in polar motion can be absorbed by GPS orbits: a retrograde signal with a period of a sidereal day (23 h 56 min 4 s) and a prograde signal with a period matching the revolution period of the GPS satellites in the terrestrial reference frame (23 h 55 min 56 s). We show that the retrograde signal contributes to the absolute orientation of the orbital planes in space and the prograde signal, due to coincidence of its period with the period of revolution of the GPS satellites, contributes to the position of the geocenter for each individual satellite. It is known from previous studies that there are systematic differences between orbital parameters from GPS solutions computed with different subdaily pole models. We show in this paper that this behavior can be explained by the absorption effects in 1-day GPS orbits. Diurnal signals cannot be spectrally separated over a time interval of 1 day. Adjustment of any diurnal prograde or retrograde signal to a subdaily pole time series given by a subdaily model over 24 h will lead to an estimated signal with a nonzero amplitude. Thus, any subdaily pole model used in the processing of space geodetic observations contains a part which corresponds numerically to the discussed prograde signal and a part which corresponds to the retrograde diurnal signal. Different pole models show different amplitudes of the diurnal signals which will be absorbed by the orbits. As a result, GPS orbits computed with different subdaily pole models have systematically different orientation and position in space. Using 1-day GPS solutions over a time span of 13 years (1994–2007), we show that the systematic variations in orbit position and orientation caused by individual tidal terms in polar motion can be well predicted and explained by the suggested mechanism. Numéro de notice : A2019-080 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1153-z Date de publication en ligne : 24/05/2018 En ligne : https://doi.org/10.1007/s00190-018-1153-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92198 [article]

Estimation of satellite position, clock and phase bias corrections / Patrick Henkel in Journal of geodesy, vol 92 n° 10 (October 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 10 (October 2018) . - pp 1199 - 1217 Titre : Estimation of satellite position, clock and phase bias corrections Type de document : Article/Communication Auteurs : Patrick Henkel, Auteur ; Dimitrios Psychas, Auteur ; Christophe Günther, Auteur ; Urs Hugentobler, Auteur Année de publication : 2018 Article en page(s) : pp 1199 - 1217 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] ambiguïté entière [Termes IGN] données Galileo [Termes IGN] données GPS [Termes IGN] double différence [Termes IGN] erreur de phase [Termes IGN] horloge atomique [Termes IGN] positionnement ponctuel précis [Termes IGN] station de référence Résumé : (Auteur) Precise point positioning with integer ambiguity resolution requires precise knowledge of satellite position, clock and phase bias corrections. In this paper, a method for the estimation of these parameters with a global network of reference stations is presented. The method processes uncombined and undifferenced measurements of an arbitrary number of frequencies such that the obtained satellite position, clock and bias corrections can be used for any type of differenced and/or combined measurements. We perform a clustering of reference stations. The clustering enables a common satellite visibility within each cluster and an efficient fixing of the double difference ambiguities within each cluster. Additionally, the double difference ambiguities between the reference stations of different clusters are fixed. We use an integer decorrelation for ambiguity fixing in dense global networks. The performance of the proposed method is analysed with both simulated Galileo measurements on E1 and E5a and real GPS measurements of the IGS network. We defined 16 clusters and obtained satellite position, clock and phase bias corrections with a precision of better than 2 cm. Numéro de notice : A2018-461 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1146-y Date de publication en ligne : 02/05/2018 En ligne : https://doi.org/10.1007/s00190-018-1146-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91060 [article]

Kindred spirits : laser ranging to GNSS satellites / Urs Hugentobler in GPS world, vol 28 n° 5 (May 2017)

Public [article]  inGPS world > vol 28 n° 5 (May 2017) . - pp 42 - 48 Titre : Kindred spirits : laser ranging to GNSS satellites Type de document : Article/Communication Auteurs : Urs Hugentobler, Auteur Année de publication : 2017 Article en page(s) : pp 42 - 48 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] constellation Galileo [Termes IGN] erreur systématique [Termes IGN] positionnement par GNSS [Termes IGN] rétroréflecteur [Termes IGN] télémétrie laser sur satellite Résumé : (Auteur) Satellite laser ranging or SLR has been an indispensable independent tool for validating the precise orbits determined for GNSS satellites using microwave pseudorange and carrierphase observations for several decades. SLR has allowed researchers to identify several orbit-modeling issues. Adding albedo radiation pressure and antenna thrust, among other effects, into the GPS orbit model allowed them to eliminate the observed bias between microwave- and SLR-derived orbits. For the first Galileo satellites launched, SLR residuals indicated severe orbit modeling issues caused by the different shape of Galileo satellite bodies compared to those of GPS. In the future, all GNSS satellites will be equipped with laser retroreflectors, a big challenge for researchers concerning tracking scenarios and observation planning to make economic use of the ground equipment. In this article, we will take a brief look at the history of laser ranging to navigation satellites, how that ranging has improved the accuracy of the orbits of those satellites, and what the future portends for this important contribution to space geodesy. Numéro de notice : A2017-293 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85329 [article]

Enhanced solar radiation pressure modeling for Galileo satellites / Oliver Montenbruck in Journal of geodesy, vol 89 n° 3 (March 2015)  

Public [article]  inJournal of geodesy > vol 89 n° 3 (March 2015) . - pp 283 - 297 Titre : Enhanced solar radiation pressure modeling for Galileo satellites Type de document : Article/Communication Auteurs : Oliver Montenbruck, Auteur ; Peter Steigenberger, Auteur ; Urs Hugentobler, Auteur Année de publication : 2015 Article en page(s) : pp 283 - 297 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales [Termes IGN] constellation Galileo [Termes IGN] Galileo [Termes IGN] GIOVE (satellite) [Termes IGN] orbitographie [Termes IGN] rayonnement solaire Résumé : (auteur) This paper introduces a new approach for modeling solar radiation pressure (SRP) effects on Global Navigation Satellite Systems (GNSSs). It focuses on the Galileo In-Orbit Validation (IOV) satellites, for which obvious SRP modeling deficits can be identified in presently available precise orbit products. To overcome these problems, the estimation of empirical accelerations in the Sun direction (D), solar panel axis (Y) and the orthogonal (B) axis is complemented by an a priori model accounting for the contribution of the rectangular spacecraft body. Other than the GPS satellites, which comprise an almost cubic body, the Galileo IOV satellites exhibit a notably rectangular shape with a ratio of about 2:1 for the main body axes. Use of the a priori box model allows to properly model the varying cross section exposed to the Sun during yaw-steering attitude mode and helps to remove systematic once-per-revolution orbit errors that have so far affected the Galileo orbit determination. Parameters of a simple a priori cuboid model suitable for the IOV satellites are established from the analysis of a long-term set of GNSS observations collected with the global network of the Multi-GNSS Experiment of the International GNSS Service. The model is finally demonstrated to reduce the peak magnitude of radial orbit errors from presently 20 cm down to 5 cm outside eclipse phases. Numéro de notice : A2015--117 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s00190-014-0774-0 Date de publication en ligne : 07/11/2014 En ligne : https://doi.org/10.1007/s00190-014-0774-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92259 [article]

Galileo orbit determination using combined GNSS and SLR observations / Stefan Hackel in GPS solutions, vol 19 n° 1 (January 2015)  

Public [article]  inGPS solutions > vol 19 n° 1 (January 2015) . - pp 15 - 25 Titre : Galileo orbit determination using combined GNSS and SLR observations Type de document : Article/Communication Auteurs : Stefan Hackel, Auteur ; Peter Steigenberger, Auteur ; Urs Hugentobler, Auteur Année de publication : 2015 Article en page(s) : pp 15 - 25 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales [Termes IGN] données TLS (télémétrie) [Termes IGN] erreur systématique [Termes IGN] GIOVE (satellite) [Termes IGN] indicateur de qualité [Termes IGN] modèle linéaire [Termes IGN] orbite [Termes IGN] orbitographie [Termes IGN] positionnement par GNSS [Termes IGN] qualité des données Résumé : (auteur) The first two Galileo In-Orbit Validation satellites were launched in October 2011 and started continuous signal transmission on all frequencies in early 2012. Both satellites are equipped with two different types of clocks, namely rubidium clocks and hydrogen masers. Based on two test periods, the quality of the Galileo orbit determination based on Global Navigation Satellite System (GNSS) and Satellite Laser Ranging (SLR) observations is assessed. The estimated satellite clock parameters are used as quality indicator for the orbits: A bump at orbital periods in the Allan deviation indicates systematic errors in the GNSS-only orbit determination. These errors almost vanish if SLR observations are considered in addition. As the internal consistency is degraded by the combination, the offset of the SLR reflector is shifted by +5 cm, resulting in an improved orbit consistency as well as accuracy. Another approach to reduce the systematic errors of the GNSS-only orbit determination employs constraints for the clock estimates with respect to a linear model. In general, one decimeter orbit accuracy could be achieved. Numéro de notice : A2015-202 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-013-0361-5 Date de publication en ligne : 09/01/2014 En ligne : https://doi.org/10.1007/s10291-013-0361-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76015 [article]

Reducing the draconitic errors in GNSS geodetic products / C.J. Rodriguez-Solano in Journal of geodesy, vol 88 n° 6 (June 2014)  

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Impact of Earth radiation pressure on GPS position estimates / C. Rodriguez-Solano in Journal of geodesy, vol 86 n° 5 (May 2012)  

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Precise orbit determination of GIOVE-B based on the CONGO network / P. Steinberger in Journal of geodesy, vol 85 n° 6 (June 2011)  

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CONGO: First GPS/GIOVE tracking network for science, research / Oliver Montenbruck in GPS world, vol 20 n° 9 (September 2009)

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First results of DORIS data analysis at Geodetic Observatory Pecný / Petr Štěpánek in Journal of geodesy, vol 80 n° 8-11 (November 2006)  

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Astrometry and satellite orbits / Urs Hugentobler (1998)  

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