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Modeling the VLBI delay for Earth satellites / Frédéric Jaron in Journal of geodesy, vol 93 n°7 (July 2019)
[article]
Titre : Modeling the VLBI delay for Earth satellites Type de document : Article/Communication Auteurs : Frédéric Jaron, Auteur ; Axel Nothnagel, Auteur Année de publication : 2019 Article en page(s) : pp 953 - 961 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] E-GRASP
[Termes IGN] Geodetic Reference Antenna in Space
[Termes IGN] interférométrie à très grande base
[Termes IGN] point de liaison (géodésie)
[Termes IGN] poursuite de satellite
[Termes IGN] propagation du signal
[Termes IGN] retard troposphérique
[Termes IGN] système international de référence célesteRésumé : (auteur) Very-long-baseline interferometry (VLBI) observations of satellites orbiting the Earth and emitting an artificial radio signal have the potential of becoming an important technique for improving the frame ties between celestial and terrestrial reference frames. Modeling the delay of the signal reception at one station with respect to the other station of a baseline is a fundamental step for correlation and parameter estimation. The near-field VLBI delay models developed so far include numerical computation, which may become expensive in terms of computation time. This applies especially when partial derivatives are to be computed, which is the normal case for least squares adjustments. Furthermore, all the models are formulated in the barycentric celestial reference system requiring large numbers. Here we present an analytical expression for the VLBI delay for the special case of satellites orbiting the Earth, observed by ground-based radio telescopes. We analytically solve the light time equation for each signal propagation path from the source to receiver one and to receiver two under the simplification of linearizing the trajectory of the satellite. By approximating the motion of the Earth as uniform during the short signal travel times we are able to work in the geocentric celestial reference system. We investigate differences between numerical and analytical solutions by simulating VLBI observations of Earth satellites. These tests reveal that delays computed with the analytical formula are consistent with those computed with the numerical solution below the detection level of VLBI but at less computational cost. Numéro de notice : A2019-354 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1217-0 Date de publication en ligne : 20/11/2018 En ligne : https://doi.org/10.1007/s00190-018-1217-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93408
in Journal of geodesy > vol 93 n°7 (July 2019) . - pp 953 - 961[article]Multi-GNSS real-time clock estimation using sequential least square adjustment with online quality control / Wenju Fu in Journal of geodesy, vol 93 n°7 (July 2019)
[article]
Titre : Multi-GNSS real-time clock estimation using sequential least square adjustment with online quality control Type de document : Article/Communication Auteurs : Wenju Fu, Auteur ; Guanwen Huang, Auteur ; Qin Zhang, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : pp 963 - 976 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] algèbre linéaire
[Termes IGN] compensation par moindres carrés
[Termes IGN] contrôle qualité
[Termes IGN] Global Positioning System
[Termes IGN] horloge du satellite
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] temps réelRésumé : (auteur) Real-time satellite orbit and clock product is a key prerequisite for real-time precise positioning service based on precise point positioning (PPP). With the rapid development of the multiple global navigation satellite systems (Multi-GNSS), about 120 satellites will be processed for Multi-GNSS real-time clock estimation. Unfortunately, the computation is very time-consuming, especially for quality control since problematic observations are inevitable. Taking advantage of computer technology, sequential least square adjustment with an adapted online quality control procedure is developed to rapidly estimate Multi-GNSS real-time clocks, although various filtering estimators are commonly used now. A globally distributed network including 70 stations tracking mostly satellites of GPS, GLONASS, BDS, and Galileo is employed for experimental validation. The results show that the computation time per epoch is less than 3 s in average and can meet the 5 s update rate of the IGS real-time clock product. Compared to the GeoForschungsZentrum MGEX (GBM) final clock product, the averaged STD values of the estimated clocks of the four GNSS systems are 0.089 ns and 0.153 ns, respectively, for the clock solutions with and without the online quality control, which also confirms the importance of the quality control procedure. The Multi-GNSS kinematic PPP experiment using the estimated clocks with quality control shows that the positioning RMS is about 4 cm and generally 2 cm in vertical and horizontal components, respectively, and the corresponding convergence time is about 15 min. Numéro de notice : A2019-355 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1218-z Date de publication en ligne : 22/11/2018 En ligne : https://doi.org/10.1007/s00190-018-1218-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93421
in Journal of geodesy > vol 93 n°7 (July 2019) . - pp 963 - 976[article]PPP-RTK based on undifferenced and uncombined observations: theoretical and practical aspects / Baocheng Zhang in Journal of geodesy, vol 93 n°7 (July 2019)
[article]
Titre : PPP-RTK based on undifferenced and uncombined observations: theoretical and practical aspects Type de document : Article/Communication Auteurs : Baocheng Zhang, Auteur ; Yongchang Chen, Auteur ; Yunbin Yuan, Auteur Année de publication : 2019 Article en page(s) : pp 1011 - 1024 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] données GNSS
[Termes IGN] mesurage de phase
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] série temporelleRésumé : (auteur) A synthesis of two prevailing global navigation satellite system positioning technologies, namely the precise point positioning and the network-based real-time kinematic, results in the emergence of the PPP-RTK, enabling single-receiver users to achieve high positioning accuracy with reasonable timeliness through integer ambiguity resolution. The realization of PPP-RTK needs to accomplish two sequential tasks. The first task is to determine a class of corrections including, among others, the satellite phase biases (SPBs) at the network level. With these corrections, the second task, then, is to solve for the ambiguity-fixed, absolute position at the user level. In this contribution, we revisit three variants (geometry-free, geometry-fixed and geometry-plus-satellite-clock-fixed) of the undifferenced and uncombined PPP-RTK network model and then point out their implications for practical use. We also carry out a case study using multi-day, dual-frequency global positioning system data from the crustal movement observation network of China stations, aiming to figure out what are the most appropriate linear combinations of the SPBs to be transmitted to the users from the viewpoint of decorrelation, and to assess the static and kinematic positioning performance. Numéro de notice : A2019-357 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1220-5 Date de publication en ligne : 06/12/2018 En ligne : https://doi.org/10.1007/s00190-018-1220-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93425
in Journal of geodesy > vol 93 n°7 (July 2019) . - pp 1011 - 1024[article]Processing of GNSS constellations and ground station networks using the raw observation approach / Sebastian Strasser in Journal of geodesy, vol 93 n°7 (July 2019)
[article]
Titre : Processing of GNSS constellations and ground station networks using the raw observation approach Type de document : Article/Communication Auteurs : Sebastian Strasser, Auteur ; Torsten Mayer-Gürr, Auteur ; Norbert Zehentner, Auteur Année de publication : 2019 Article en page(s) : pp 1045 - 1057 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse diachronique
[Termes IGN] antenne GNSS
[Termes IGN] constellation GNSS
[Termes IGN] données GPS
[Termes IGN] erreur systématique
[Termes IGN] étalonnage d'instrument
[Termes IGN] Global Orbitography Navigation Satellite System
[Termes IGN] horloge du satellite
[Termes IGN] orbitographie
[Termes IGN] position
[Termes IGN] repère de référence
[Termes IGN] retard ionosphèrique
[Termes IGN] station GNSS
[Termes IGN] station GPSRésumé : (auteur) This article describes the raw observation approach as implemented at Graz University of Technology to determine GNSS products like satellite orbits, clocks, and station positions. To assess the performance of the approach, 15 years (2003–2017) of observations from a network of 245 globally distributed IGS stations to the GPS constellation were processed on a daily basis using the IGS14 reference frame and antenna calibrations. The resulting products are evaluated against those determined by IGS analysis centers. Orbit fit quality relative to the IGS combination is comparable to the best-fitting solutions used for evaluation. Starting from early 2017, when the IGS switched to IGS14, the determined orbits fit better to the IGS combination than any other considered solution. Midnight discontinuities show good internal orbit consistency and no noticeable satellite block-dependency. Satellite clocks are comparable to the considered IGS analysis center solutions. Station positions differ from the IGS combination on a similar level to the solutions they were evaluated against. The temporal repeatability of station positions is slightly better than that of the IGS combination. The quality of resulting GNSS products confirms that the raw observation approach is well suited for the task of determining satellite orbits, clocks, and station positions. It provides an alternative to well-established approaches used by IGS analysis centers and simplifies the introduction of additional observables from new and modernized GNSS. Numéro de notice : A2019-358 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-1223-2 Date de publication en ligne : 13/12/2018 En ligne : https://doi.org/10.1007/s00190-018-1223-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93426
in Journal of geodesy > vol 93 n°7 (July 2019) . - pp 1045 - 1057[article]Sensitivity of GPS tropospheric estimates to mesoscale convective systems in West Africa / Samuel Nahmani in Atmospheric chemistry and physics, vol 19 n° 14 (July 2019)
[article]
Titre : Sensitivity of GPS tropospheric estimates to mesoscale convective systems in West Africa Type de document : Article/Communication Auteurs : Samuel Nahmani , Auteur ; Olivier Bock , Auteur ; Françoise Guichard, Auteur Année de publication : 2019 Projets : VEGAN / Bock, Olivier, TOSCA / Bock, Olivier Article en page(s) : pp 9541 - 9561 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] Afrique occidentale
[Termes IGN] analyse de sensibilité
[Termes IGN] bande C
[Termes IGN] convection
[Termes IGN] données GPS
[Termes IGN] GAMIT
[Termes IGN] GIPSY-OASIS
[Termes IGN] gradient de troposphère
[Termes IGN] meso échelle
[Termes IGN] modèle atmosphérique
[Termes IGN] Niger
[Termes IGN] propagation troposphérique
[Termes IGN] résidu
[Termes IGN] retard troposphérique zénithal
[Termes IGN] signal GPSRésumé : (Auteur) This study analyzes the characteristics of GPS tropospheric estimates (zenith wet delays – ZWDs, gradients, and post-fit phase residuals) during the passage of mesoscale convective systems (MCSs) and evaluates their sensitivity to the research-level GPS data processing strategy implemented. Here, we focus on MCS events observed during the monsoon season of West Africa. This region is particularly well suited for the study of these events due to the high frequency of MCS occurrences in the contrasting climatic environments between the Guinean coast and the Sahel. This contrast is well sampled with data generated by six African Monsoon Multidisciplinary Analysis (AMMA) GPS stations. Tropospheric estimates for a 3-year period (2006–2008), processed with both the GAMIT and GIPSY-OASIS software packages, were analyzed and intercompared. First, the case of a MCS that passed over Niamey, Niger, on 11 August 2006 demonstrates a strong impact of the MCS on GPS estimates and post-fit residuals when the GPS signals propagate through the convective cells as detected on reflectivity maps from the MIT C-band Doppler radar. The estimates are also capable of detecting changes in the structure and dynamics of the MCS. However, the sensitivity is different depending on the tropospheric modeling approach adopted in the software. With GIPSY-OASIS, the high temporal sampling (5 min) of ZWDs and gradients is well suited for detecting the small-scale, short-lived, convective cells, while the post-fit residuals remain quite small. With GAMIT, the lower temporal sampling of the estimated parameters (hourly for ZWDs and daily for gradients) is not sufficient to capture the rapid delay variations associated with the passage of the MCS, but the post-fit phase residuals clearly reflect the presence of a strong refractivity anomaly. The results are generalized with a composite analysis of 414 MCS events observed over the 3-year period at the six GPS stations with the GIPSY-OASIS estimates. A systematic peak is found in the ZWDs coincident with the cold pool crossing time associated with the MCSs. The tropospheric gradients reflect the path of the MCS propagation (generally from east to west). This study concludes that ZWDs, gradients, and post-fit phase residuals provide relevant and complementary information on MCSs passing over or in the vicinity of a GPS station. Numéro de notice : A2019-572 Affiliation des auteurs : Géodésie+Ext (mi2018-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/acp-19-9541-2019 Date de publication en ligne : 29/07/2019 En ligne : https://doi.org/10.5194/acp-19-9541-2019 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94444
in Atmospheric chemistry and physics > vol 19 n° 14 (July 2019) . - pp 9541 - 9561[article]Du NRTK vers le PPP-RTK, un exemple avec TERIA / Paul Chambon in XYZ, n° 159 (juin 2019)PermalinkSeasonal pattern in time series of variances of GPS residual errors Anova estimates / Darko Anđić in Geodetski vestnik, vol 63 n° 2 (June - August 2019)PermalinkAbility of GPS PPP in 2D deformation analysis with respect to GPS network solution / C. Aydin in Survey review, vol 51 n° 366 (May 2019)PermalinkAn improved robust Kalman filtering strategy for GNSS kinematic positioning considering small cycle slips / Wanke Liu in Advances in space research, vol 63 n° 9 (1 May 2019)PermalinkReal-time GPS satellite orbit and clock estimation based on OpenMP / Kaifa Kuang in Advances in space research, vol 63 n° 8 (15 April 2019)PermalinkConstellations, réseaux permanents, PPP : état des lieux / Laurent Morel in Géomètre, n° 2168 (avril 2019)PermalinkGéolocalisation, l'âge d'or débute à peine / Michel Kasser in Géomètre, n° 2168 (avril 2019)PermalinkGPS inter-frequency clock bias estimation for both uncombined and ionospheric-free combined triple-frequency precise point positioning / Lin Pan in Journal of geodesy, vol 93 n° 4 (April 2019)PermalinkOn-the-fly ambiguity resolution involving only carrier phase measurements for stand-alone ground-based positioning systems / Tengfei Wang in GPS solutions, vol 23 n° 2 (April 2019)PermalinkLe réseau GPS permanent (RGP) de l'IGN / Sébastien Saur in Géomètre, n° 2168 (avril 2019)PermalinkLes services Teria / Paul Chambon in Géomètre, n° 2168 (avril 2019)PermalinkTeria : la géolocalisation de haute précision / Paul Chambon in Géomètre, n° 2168 (avril 2019)PermalinkEvaluation of the IRI-2016 and NeQuick electron content specification by COSMIC GPS radio occultation, ground-based GPS and Jason-2 joint altimeter/GPS observations / Iurii Cherniak in Advances in space research, vol 63 n° 6 (15 March 2019)PermalinkImpact of predicting real-time clock corrections during their outages on precise point positioning / Ahmed El-Mowafy in Survey review, vol 51 n° 365 (March 2019)PermalinkThe impact of relative and absolute GNSS positioning strategies on estimated coordinates and ZWD in the framework of meteorological applications / Alessandro Fermi in Applied geomatics, vol 11 n° 1 (March 2019)PermalinkAccounting for the differential inter-system bias (DISB) of code observation in GPS+BDS positioning / Xiang Cao in Journal of applied geodesy, vol 13 n° 1 (January 2019)PermalinkAnalysis of GPS satellite clock prediction performance with different update intervals and application to real-time PPP / H. Yang in Survey review, vol 51 n° 364 (January 2019)PermalinkCorrelated atom accelerometers for mapping the Earth gravity field from space / Thomas Lévèque (2019)PermalinkEnhancing real-time precise point positioning time and frequency transfer with receiver clock modeling / Yulong Ge in GPS solutions, vol 23 n° 1 (January 2019)PermalinkEstimating and assessing Galileo satellite fractional cycle bias for PPP ambiguity resolution / Guorui Xiao in GPS solutions, vol 23 n° 1 (January 2019)Permalink