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Estimation and representation of regional atmospheric corrections for augmenting real-time single-frequency PPP / Peiyuan Zhou in GPS solutions, vol 24 n° 1 (January 2020)  

Public [article]  inGPS solutions > vol 24 n° 1 (January 2020) Titre : Estimation and representation of regional atmospheric corrections for augmenting real-time single-frequency PPP Type de document : Article/Communication Auteurs : Peiyuan Zhou, Auteur ; Jin Wang, Auteur ; Zhixi Nie, Auteur ; Yang Gao, Auteur Année de publication : 2020 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] correction atmosphérique [Termes IGN] correction ionosphérique [Termes IGN] correction troposphérique [Termes IGN] décalage d'horloge [Termes IGN] positionnement ponctuel précis [Termes IGN] Quasi-Zenith Satellite System [Termes IGN] récepteur monofréquence [Termes IGN] retard ionosphèrique [Termes IGN] retard troposphérique [Termes IGN] satellite GPS [Termes IGN] station GNSS [Termes IGN] temps réel [Termes IGN] teneur totale en électrons Résumé : (Auteur) Real-time single-frequency precise point positioning (PPP) can be significantly augmented by applying high-quality atmospheric corrections. In previous work, the satellite-and-station-specific slant total electron content (STEC) ionospheric corrections, derived from a regional reference network, are commonly used to augment single-frequency PPP for improving positioning accuracy and faster convergence. However, since the users are required to interpolate STEC ionospheric corrections from nearby reference stations, either duplex communication links should be established or all corrections of the reference network must be retrieved, which makes it inefficient to provide augmentation services to many users. Moreover, the regional tropospheric corrections are generally neglected in augmenting real-time single-frequency PPP. In this study, we present a method to estimate and represent tropospheric and ionospheric corrections from a regional reference network, which can be efficiently disseminated to users through a simplex communication link. First, the uncombined dual-frequency PPP, with external ionospheric constraints derived from international GNSS service predicted global ionospheric map, is used for estimating atmospheric delays with observations from a regional GNSS reference network. Then, the atmospheric delays are properly represented to facilitate real-time transmission by applying a polynomial model for the representation of zenith wet tropospheric corrections, and satellite-specific STEC maps for representing the slant ionospheric corrections. The above results in only simple communication links required to retrieve the regional atmospheric corrections for real-time single-frequency PPP augmentation. Observations from a regional network of 30 GNSS reference stations with inter-station distances of about 70 km during a 1-week-long period, including both quiet and active geomagnetic conditions, are used for generating the regional atmospheric corrections. The results indicate that the average root-mean-square errors of the obtained regional tropospheric and ionospheric corrections are better than 0.01 and 0.05 m when compared with those derived from dual-frequency uncombined PPP, respectively. The positioning accuracy of the single-frequency PPP augmented with regional atmospheric corrections is at 0.141 m horizontally and 0.206 m vertically under a 95% confidence level, a significant improvement compared to single-frequency PPP without atmospheric augmentation. The convergence time is also significantly reduced with 70.4% of the positioning sessions achieving instantaneous 3D convergence. Numéro de notice : A2020-023 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-019-0920-5 Date de publication en ligne : 13/11/2019 En ligne : https://doi.org/10.1007/s10291-019-0920-5 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94466 [article]

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]

GPS satellite clock determination in case of inter-frequency clock biases for triple-frequency precise point positioning / Jiang Guo in Journal of geodesy, vol 92 n° 10 (October 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 10 (October 2018) . - pp 1133 - 1142 Titre : GPS satellite clock determination in case of inter-frequency clock biases for triple-frequency precise point positioning Type de document : Article/Communication Auteurs : Jiang Guo, Auteur ; Jianghui Geng, Auteur Année de publication : 2018 Article en page(s) : pp 1133 - 1142 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] erreur systématique [Termes IGN] horloge atomique [Termes IGN] positionnement ponctuel précis [Termes IGN] satellite GPS Résumé : (Auteur) Significant time-varying inter-frequency clock biases (IFCBs) within GPS observations prevent the application of the legacy L1/L2 ionosphere-free clock products on L5 signals. Conventional approaches overcoming this problem are to estimate L1/L5 ionosphere-free clocks in addition to their L1/L2 counterparts or to compute IFCBs between the L1/L2 and L1/L5 clocks which are later modeled through a harmonic analysis. In contrast, we start from the undifferenced uncombined GNSS model and propose an alternative approach where a second satellite clock parameter dedicated to the L5 signals is estimated along with the legacy L1/L2 clock. In this manner, we do not need to rely on the correlated L1/L2 and L1/L5 ionosphere-free observables which complicates triple-frequency GPS stochastic models, or account for the unfavorable time-varying hardware biases in undifferenced GPS functional models since they can be absorbed by the L5 clocks. An extra advantage over the ionosphere-free model is that external ionosphere constraints can potentially be introduced to improve PPP. With 27 days of triple-frequency GPS data from globally distributed stations, we find that the RMS of the positioning differences between our GPS model and all conventional models is below 1 mm for all east, north and up components, demonstrating the effectiveness of our model in addressing triple-frequency observations and time-varying IFCBs. Moreover, we can combine the L1/L2 and L5 clocks derived from our model to calculate precisely the L1/L5 clocks which in practice only depart from their legacy counterparts by less than 0.006 ns in RMS. Our triple-frequency GPS model proves convenient and efficient in combating time-varying IFCBs and can be generalized to more than three frequency signals for satellite clock determination. Numéro de notice : A2018-460 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1106-y Date de publication en ligne : 28/12/2017 En ligne : https://doi.org/10.1007/s00190-017-1106-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91057 [article]

Multi-technique combination of space geodesy observations: Impact of the Jason-2 satellite on the GPS satellite orbits estimation / Myriam Zoulida in Advances in space research, vol 58 n° 7 (October 2016)  

Public [article]  inAdvances in space research > vol 58 n° 7 (October 2016) . - pp 1376 - 1389 Titre : Multi-technique combination of space geodesy observations: Impact of the Jason-2 satellite on the GPS satellite orbits estimation Type de document : Article/Communication Auteurs : Myriam Zoulida , Auteur ; Arnaud Pollet , Auteur ; David Coulot , Auteur ; Félix Perosanz, Auteur ; Sylvain Loyer, Auteur ; Richard Biancale, Auteur ; Paul Rebischung , Auteur Année de publication : 2016 Article en page(s) : pp 1376 - 1389 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] données Jason [Termes IGN] orbitographie [Termes IGN] satellite GPS [Vedettes matières IGN] Traitement de données GNSS Résumé : (auteur) In order to improve the Precise Orbit Determination (POD) of the GPS constellation and the Jason-2 Low Earth Orbiter (LEO), we carry out a simultaneous estimation of GPS satellite orbits along with Jason-2 orbits, using GINS software. Along with GPS station observations, we use Jason-2 GPS, SLR and DORIS observations, over a data span of 6 months (28/05/2011–03/12/2011). We use the Geophysical Data Records-D (GDR-D) orbit estimation standards for the Jason-2 satellite. A GPS-only solution is computed as well, where only the GPS station observations are used. It appears that adding the LEO GPS observations results in an increase of about 0.7% of ambiguities fixed, with respect to the GPS-only solution. The resulting GPS orbits from both solutions are of equivalent quality, agreeing with each other at about 7 mm on Root Mean Square (RMS). Comparisons of the resulting GPS orbits to the International GNSS Service (IGS) final orbits show the same level of agreement for both the GPS-only orbits, at 1.38 cm in RMS, and the GPS + Jason2 orbits at 1.33 cm in RMS. We also compare the resulting Jason-2 orbits with the 3-technique Segment Sol multi-missions d’ALTimétrie, d’orbitographie et de localisation précise (SSALTO) POD products. The orbits show good agreement, with 2.02 cm of orbit differences global RMS, and 0.98 cm of orbit differences RMS on the radial component. Numéro de notice : A2016-963 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.06.019 Date de publication en ligne : 22/06/2016 En ligne : http://dx.doi.org/10.1016/j.asr.2016.06.019 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83580 [article]

GPS IIF-1 satellite: Antenna phase center and attitude modeling / F. Dilssner in Inside GNSS, vol 5 n° 6 (September 2010) 

Public [article]  inInside GNSS > vol 5 n° 6 (September 2010) . - 6 p. ; pp 59 - 64 Titre : GPS IIF-1 satellite: Antenna phase center and attitude modeling Type de document : Article/Communication Auteurs : F. Dilssner, Auteur Année de publication : 2010 Article en page(s) : 6 p. ; pp 59 - 64 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] antenne GPS [Termes IGN] centre de phase [Termes IGN] orientation du capteur [Termes IGN] phase GPS [Termes IGN] satellite GPS Résumé : (Auteur) Calculating the distances between satellites and user equipment is a basic operation for GNSS positioning. More precisely, these ranges are measured from the antenna phase centers of the satellites’ transmitting antenna. However, phase centers vary among types and generations of spacecraft and, further, the calculation requires knowledge of a satellite’s orientation or attitude. A researcher at the European Space Operations Center has analyzed the initial performance of the first GPS Block IIF space vehicle and found some expected - and unexpected - results. Numéro de notice : A2010-672 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33454 [article]

Documents numériques

peut être téléchargé GPS IIF-1 satellite ... - scan Adobe Acrobat PDF

Making sense of inter-signal corrections: accounting for GPS satellite calibration parameters in legacy and modernized ionosphere correction algorithms / Avram Tetewsky in Inside GNSS, vol 4 n° 4 (July - August 2009) 

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Modelling and prediction of GPS availability with digital photogrammetry and LiDAR / Georges E. Taylor in International journal of geographical information science IJGIS, vol 21 n° 1-2 (january 2007)  

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Thermal re-emission effects on GPS satellites / J. Duha in Journal of geodesy, vol 80 n° 12 (December 2006)  

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New, improved GPS: the legacy accuracy improvement initiative / T. Creel in GPS world, vol 17 n° 3 (March 2006)

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Naviguer dans le monde sans fil : un aperçu de l'influence exercée par la technologie sans fil sur les topographes / N. Pugh in XYZ, n° 104 (septembre - novembre 2005)

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Monitoring GPS receiver and satellite clocks in real time: a network approach / François Lahaye in GPS world, vol 12 n° 11 (November 2001)

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Modeling and validating orbits and clocks using the Global Positioning System / Tim A. Springer (2000)  

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Geophysical distributions of occultations of GPS satellites viewed from a low Earth orbiting satellite / D.M. O'Brien (1998)

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Scientific applications of GPS and GLONASS : a challenge for GNSS [for] Colloque GNSS, Toulouse, 20 - 23 octobre 1998 / Claude Boucher (1998)

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Determining the GPS orbit with the dynamic collocation model / L. Quanwei (1996)

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