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Les évolutions du PPP : l'apport d'une troisième fréquence pour réduire les temps de convergence / Denis Laurichesse in XYZ, n° 144 (septembre - novembre 2015)
[article]
Titre : Les évolutions du PPP : l'apport d'une troisième fréquence pour réduire les temps de convergence Type de document : Article/Communication Auteurs : Denis Laurichesse, Auteur Année de publication : 2015 Article en page(s) : pp 59 - 63 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] erreur systématique
[Termes IGN] positionnement ponctuel précis
[Termes IGN] récepteur trifréquence
[Termes IGN] résolution d'ambiguïté
[Termes IGN] temps de convergenceRésumé : (auteur) Le PPP est une technique de positionnement émergente qui possède de nombreux avantages. Parmi ceux-ci, on pourra noter la facilité d'utilisation, le coût réduit de l'infrastructure réseau comparée à des techniques différentielles, la possibilité de n'utiliser qu'une liaison monodirectionnelle et à faible débit pour l'envoi des corrections. Un des défauts majeurs de la technique est la relative lenteur de convergence (environ 30 minutes dans le cas bi-fréquence). Nous montrons ici que, grâce à l'utilisation d'une représentation appropriée pour les corrections de biais (erreur systématique) de phases ainsi que grâce au traitement d'une troisième fréquence, il est possible de réduire ce temps à quelques minutes, dans le cas du GPS. Numéro de notice : A2015-638 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78126
in XYZ > n° 144 (septembre - novembre 2015) . - pp 59 - 63[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 112-2015031 RAB Revue Centre de documentation En réserve L003 Disponible Documents numériques
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Les évolutions du PPP - pdf éditeurAdobe Acrobat PDF Real-time retrieval of precipitable water vapor from GPS and BeiDou observations / Cuixian Lu in Journal of geodesy, vol 89 n° 9 (september 2015)
[article]
Titre : Real-time retrieval of precipitable water vapor from GPS and BeiDou observations Type de document : Article/Communication Auteurs : Cuixian Lu, Auteur ; Xinging Li, Auteur ; Tobias Nilsson, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 843 - 856 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] positionnement ponctuel précis
[Termes IGN] précipitation
[Termes IGN] propagation troposphérique
[Termes IGN] retard troposphérique zénithal
[Termes IGN] signal BeiDou
[Termes IGN] signal GPS
[Termes IGN] vapeur d'eauRésumé : (auteur) The rapid development of the Chinese BeiDou Navigation Satellite System (BDS) brings a promising prospect for the real-time retrieval of zenith tropospheric delays (ZTD) and precipitable water vapor (PWV), which is of great benefit for supporting the time-critical meteorological applications such as nowcasting or severe weather event monitoring. In this study, we develop a real-time ZTD/PWV processing method based on Global Positioning System (GPS) and BDS observations. The performance of ZTD and PWV derived from BDS observations using real-time precise point positioning (PPP) technique is carefully investigated. The contribution of combining BDS and GPS for ZTD/PWV retrieving is evaluated as well. GPS and BDS observations of a half-year period for 40 globally distributed stations from the International GNSS Service Multi-GNSS Experiment and BeiDou Experiment Tracking Network are processed. The results show that the real-time BDS-only ZTD series agree well with the GPS-only ZTD series in general: the RMS values are about 11–16 mm (about 2–3 mm in PWV). Furthermore, the real-time ZTD derived from GPS-only, BDS-only, and GPS/BDS combined solutions are compared with those derived from the Very Long Baseline Interferometry. The comparisons show that the BDS can contribute to real-time meteorological applications, slightly less accurately than GPS. More accurate and reliable water vapor estimates, about 1.3–1.8 mm in PWV, can be obtained if the BDS observations are combined with the GPS observations in the real-time PPP data processing. The PWV comparisons with radiosondes further confirm the performance of BDS-derived real-time PWV and the benefit of adding BDS to standard GPS processing. Numéro de notice : A2015-875 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0818-0 Date de publication en ligne : 28/04/2015 En ligne : https://doi.org/10.1007/s00190-015-0818-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79394
in Journal of geodesy > vol 89 n° 9 (september 2015) . - pp 843 - 856[article]Impacts of real-time satellite clock errors on GPS precise point positioning-based troposphere zenith delay estimation / Junbo Shi in Journal of geodesy, vol 89 n° 8 (August 2015)
[article]
Titre : Impacts of real-time satellite clock errors on GPS precise point positioning-based troposphere zenith delay estimation Type de document : Article/Communication Auteurs : Junbo Shi, Auteur ; Chaoqian Xu, Auteur ; Yihe Li, Auteur ; Yang Gao, Auteur Année de publication : 2015 Article en page(s) : pp 747-756 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] erreur corrélée au temps
[Termes IGN] horloge atomique
[Termes IGN] orbite précise
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] retard troposphérique zénithal
[Termes IGN] temps réel
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) Global Positioning System (GPS) has become a cost-effective tool to determine troposphere zenith total delay (ZTD) with accuracy comparable to other atmospheric sensors such as the radiosonde, the water vapor radiometer, the radio occultation and so on. However, the high accuracy of GPS troposphere ZTD estimates relies on the precise satellite orbit and clock products available with various latencies. Although the International GNSS Service (IGS) can provide predicted orbit and clock products for real-time applications, the predicted clock accuracy of 3 ns cannot always guarantee the high accuracy of troposphere ZTD estimates. Such limitations could be overcome by the use of the newly launched IGS real-time service which provides ∼5 cm orbit and 0.2–1.0 ns (an equivalent range error of 6–30 cm) clock products in real time. Considering the relatively larger magnitude of the clock error than that of the orbit error, this paper investigates the effect of real-time satellite clock errors on the GPS precise point positioning (PPP)-based troposphere ZTD estimation. Meanwhile, how the real-time satellite clock errors impact the GPS PPP-based troposphere ZTD estimation has also been studied to obtain the most precise ZTD solutions. First, two types of real-time satellite clock products are assessed with respect to the IGS final clock product in terms of accuracy and precision. Second, the real-time GPS PPP-based troposphere ZTD estimation is conducted using data from 34 selected IGS stations over three independent weeks in April, July and October, 2013. Numerical results demonstrate that the precision, rather than the accuracy, of the real-time satellite clock products impacts the real-time PPP-based ZTD solutions more significantly. In other words, the real-time satellite clock product with better precision leads to more precise real-time PPP-based troposphere ZTD solutions. Therefore, it is suggested that users should select and apply real-time satellite products with better clock precision to obtain more consistent real-time PPP-based ZTD solutions. Numéro de notice : A2015-374 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0811-7 Date de publication en ligne : 04/04/2015 En ligne : https://doi.org/10.1007/s00190-015-0811-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76852
in Journal of geodesy > vol 89 n° 8 (August 2015) . - pp 747-756[article]Single-frequency precise point positioning: an analytical approach / Oskar Sterle in Journal of geodesy, vol 89 n° 8 (August 2015)
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Titre : Single-frequency precise point positioning: an analytical approach Type de document : Article/Communication Auteurs : Oskar Sterle, Auteur ; Bojan Stopar, Auteur ; Polona Pavlovčič Prešeren, Auteur Année de publication : 2015 Article en page(s) : pp 793-810 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse comparative
[Termes IGN] analyse de données
[Termes IGN] coordonnées géographiques
[Termes IGN] horloge
[Termes IGN] positionnement ponctuel précis
[Termes IGN] propagation troposphérique
[Termes IGN] récepteur monofréquence
[Termes IGN] station permanente
[Termes IGN] transformation de Helmert
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) An analytical approach to single-frequency precise point positioning (PPP) is discussed in this paper. To obtain highest precision results, all biases must be eliminated or modelled to centimetre level. The use of the GRAPHIC ionosphere-free linear combination that is based on single-frequency phase and code observations eliminates the ionosphere bias; however, the rank deficient Gauss–Markov model is obtained. We explicitly determine rank deficiency of a Gauss–Markov model as a number of all ambiguity clusters, each of them defined as a set of all ambiguities overlapping in time. On the basis of S-transformation we prove that the single-frequency PPP represents an unbiased estimator for station coordinates and troposphere parameters, while it presents a biased estimator for ambiguities and receiver-clock error parameters. Additionally we describe the estimable parameters in each ambiguity cluster as the differences between ambiguity parameters and the sum of receiver-clock parameters with one of the ambiguities. We also show that any other particular solution on the basis of S-transformation is obtained only when the common least-squares estimation in single step is applied. The recursive least-squares estimation with parameter pre-elimination only determines the vector of unknowns as possible to transform through S-transformation, whereas the same does not hold for the cofactor matrix of unknowns. For a case study, we present our method on GPS data from 19 permanent stations (14 IGS and 5 EPN) in Europe, for 89 consecutive days in the beginning of 2013. The static case study revealed the precision of daily coordinates as 7.6, 11.7 and 19.6 mm for N, E and U, respectively. The accuracies of the N, E and U components were determined as 6.9, 13.5 and 31.4 mm, respectively, and were calculated using the Helmert transformation of weighted-mean daily single-frequency PPP and IGb08 coordinates. The estimated convergence times were relatively diverse, expanding from 1.75 h (CAGL) to 5.25 h (GRAZ) for the horizontal position with the 10-cm precision threshold, and from 1.00 h (GRAS) to 3.25 h (BZRG) for the height component with a 20-cm precision threshold. The convergence times were shown to be strongly correlated to the remaining unmodelled biases in the GRAPHIC linear combination, primarily with multipath, where the correlation coefficient for the horizontal position was determined as ρP = 0.68 and for height as ρU = 0.85. The comparison to the model where raw observations are used (C, L) and where the ionosphere bias is mitigated with global ionosphere models (GIM) revealed the supremacy of the proposed single-frequency PPP method based on the GRAPHIC linear combination in both the static and the semi-kinematic case study. In the static case study, the proposed single-frequency PPP model was superior both in terms of precision and accuracy. In the semi-kinematic case study, the usage of raw observations with GIM would improve results only when multipath and noise of code observations would prevail over the remaining ionosphere bias, i.e. after applying GIM. Numéro de notice : A2015-377 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0816-2 Date de publication en ligne : 29/04/2015 En ligne : https://doi.org/10.1007/s00190-015-0816-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76855
in Journal of geodesy > vol 89 n° 8 (August 2015) . - pp 793-810[article]A worldwide ionospheric model for fast precise point positioning / Adria Rovira-Garcia in IEEE Transactions on geoscience and remote sensing, vol 53 n° 8 (August 2015)
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Titre : A worldwide ionospheric model for fast precise point positioning Type de document : Article/Communication Auteurs : Adria Rovira-Garcia, Auteur ; José Miguel Juan, Auteur ; Jaume Sanz, Auteur ; Guillermo Gonzalez-Casado, Auteur Année de publication : 2015 Article en page(s) : pp 4596 - 4604 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] correction ionosphérique
[Termes IGN] modèle ionosphérique
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] résolution d'ambiguïté
[Termes IGN] temps réel
[Vedettes matières IGN] Traitement de données GNSSRésumé : (Auteur) Fast precise point positioning (Fast-PPP) is a satellite-based navigation technique using an accurate real-time ionospheric modeling to achieve high accuracy quickly. In this paper, an end-to-end performance assessment of Fast-PPP is presented in near-maximum Solar Cycle conditions; from the accuracy of the Central Processing Facility corrections, to the user positioning. A planetary distribution of permanent receivers including challenging conditions at equatorial latitudes, is navigated in pure kinematic mode, located from 100 to 1300 km away from the nearest reference station used to derive the ionospheric model. It is shown that satellite orbits and clocks accurate to few centimeters and few tenths of nanoseconds, used in conjunction with an ionosphere with an accuracy better than 1 Total Electron Content Unit (16 cm in L1) reduce the convergence time of dual-frequency Precise Point Positioning, to decimeter-level (3-D) solutions. Horizontal convergence times are shortened 40% to 90%, whereas the vertical components are reduced by 20% to 60%. A metric to evaluate the quality of any ionospheric model for Global Navigation Satellite System is also proposed. The ionospheric modeling accuracy is directly translated to mass-market single-frequency users. The 95th percentile of horizontal and vertical accuracies is shown to be 40 and 60 cm for single-frequency users and 9 and 16 cm for dual-frequency users. The tradeoff between the formal and actual positioning errors has been carefully studied to set realistic confidence levels to the corrections. Numéro de notice : A2015-389 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2015.2402598 En ligne : https://doi.org/10.1109/TGRS.2015.2402598 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76869
in IEEE Transactions on geoscience and remote sensing > vol 53 n° 8 (August 2015) . - pp 4596 - 4604[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-2015081 RAB Revue Centre de documentation En réserve L003 Disponible Reduction of PPP convergence period through pseudorange multipath and noise mitigation / Garrett Seepersad in GPS solutions, vol 19 n° 3 (July 2015)PermalinkWeighted total least squares for solving non-linear problem: GNSS point positioning / S. Jazaeri in Survey review, vol 47 n° 343 (July 2015)PermalinkAccuracy and reliability of multi-GNSS real-time precise positioning: GPS, GLONASS, BeiDou, and Galileo / Xinging Li in Journal of geodesy, vol 89 n° 6 (June 2015)PermalinkAn improved between-satellite single-difference precise point positioning model for combined GPS/Galileo observations / Akram Afifi in Journal of applied geodesy, vol 9 n° 2 (June 2015)PermalinkGNSS-WARP software for real-time precise point positioning / Tomasz Hadas in Artificial satellites, vol 50 n° 2 (June 2015)PermalinkImpact of ocean tides loading on precise point positioning based on FES2004 model / J.Z. Kalita in Artificial satellites, vol 50 n° 2 (June 2015)PermalinkReal-time GPS precise point positioning-based precipitable water vapor estimation for rainfall monitoring and forecasting / Junbo Shi in IEEE Transactions on geoscience and remote sensing, vol 53 n° 6 (June 2015)PermalinkIonospheric effects in uncalibrated phase delay estimation and ambiguity-fixed PPP based on raw observable model / Shengfeng Gu in Journal of geodesy, vol 89 n° 5 (May 2015)PermalinkCarrier-phase ambiguity resolution: Handling the biases for improved triple-frequency PPP convergence / Denis Laurichesse in GPS world, vol 26 n° 4 (April 2015)PermalinkAn innovative dual frequency PPP model for combined GPS/Galileo observations / Akram Afifi in Journal of applied geodesy, vol 9 n° 1 (March 2015)Permalink