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Ambiguity resolution for triple-frequency geometry-free and ionosphere-free combination tested with real data / K. Wang in Journal of geodesy, vol 87 n° 6 (June 2013)
[article]
Titre : Ambiguity resolution for triple-frequency geometry-free and ionosphere-free combination tested with real data Type de document : Article/Communication Auteurs : K. Wang, Auteur ; Markus Rothacher, Auteur Année de publication : 2013 Article en page(s) : pp 539 - 553 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] combinaison linéaire
[Termes IGN] filtrage du bruit
[Termes IGN] mesurage de la fréquence
[Termes IGN] phase GNSS
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal BeiDou
[Termes IGN] signal Galileo
[Termes IGN] signal GNSSRésumé : (Auteur) The recent GPS Block IIF satellites SVN62 and SVN63 and the Galileo satellites GIOVE-A, GIOVE-B, PFM and FM2 already send signals on more than two frequencies, and more GNSS satellites will provide tracking data on at least three frequencies in the near future. In this paper, a simplified general method for ambiguity resolution minimizing the noise level for the triple-frequency geometry-free (GF) and ionosphere-free (IF) linear combinations is presented, where differently scaled code noise on the three frequencies was introduced. For the third of three required linear combinations, the most demanding one in triple-frequency ambiguity resolution, we developed a general method using the ambiguity-corrected phase observations without any constraints to search for the optimal GF and IF linear combination. We analytically demonstrate that the noise level of this third linear combination only depends on the three frequencies. The investigation concerning this frequency-dependent noise factor was performed for GPS, Galileo and Compass frequency triplets. We verified the theoretical derivations with real triple-frequency GPS and Galileo data from the Multi-GNSS Experiment (M–GEX) of the International GNSS Service (IGS). The data of about 30 M–GEX stations around the world over 11 days from 29 April 2012 to 9 May 2012 were used for the test. For the third linear combinaton using Galileo E1, E5b and E5a, which is expected to have the worst performance among all the GNSS frequency triplets in our investigation, the formal errors of the estimated ambiguities are in most cases below 0.2 cycles after 400 observation epochs. If more GPS satellites sending signals on three frequencies or more stations tracking Galileo E6 signal are available in the future, an improvement by a factor of two to three can be expected. Numéro de notice : A2013-339 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0630-7 Date de publication en ligne : 09/04/2013 En ligne : https://doi.org/10.1007/s00190-013-0630-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32477
in Journal of geodesy > vol 87 n° 6 (June 2013) . - pp 539 - 553[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2013061 SL Revue Centre de documentation Revues en salle Disponible Assessment of correct fixing rate for precise point positioning ambiguity resolution on a global scale / Xiaohong Zhang in Journal of geodesy, vol 87 n° 6 (June 2013)
[article]
Titre : Assessment of correct fixing rate for precise point positioning ambiguity resolution on a global scale Type de document : Article/Communication Auteurs : Xiaohong Zhang, Auteur ; Pan Li, Auteur Année de publication : 2013 Article en page(s) : pp 579 - 589 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] dégradation du signal
[Termes IGN] données GPS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] propagation ionosphérique
[Termes IGN] résolution d'ambiguïté
[Termes IGN] simple différence
[Termes IGN] variance de phaseRésumé : (Auteur) Ambiguity resolution (AR) for a single receiver has been a popular topic in Global Positioning System (GPS) recently. Ambiguity-resolution methods for precise point positioning (PPP) have been well documented in recent years, demonstrating that it can improve the accuracy of PPP. However, users are often concerned about the reliability of ambiguity-fixed PPP solution in practical applications. If ambiguities are fixed to wrong integers, large errors would be introduced into position estimates. In this paper, we aim to assess the correct fixing rate (CFR), i.e., number of ambiguities correctly fixing to the total number of ambiguities correctly and incorrectly fixing, for PPP user ambiguity resolution on a global scale. A practical procedure is presented to evaluate the CFR of PPP user ambiguity resolution. GPS data of the first 3 days in each month of 2010 from about 390 IGS stations are used for experiments. Firstly, we use GPS data collected from about 320 IGS stations to estimate global single-differenced (SD) wide-lane and narrow-lane satellite uncalibrated phase delays (UPDs). The quality of UPDs is evaluated. We found that wide-lane UPD estimates have a rather small standard deviation (Std) between 0.003 and 0.004 cycles while most of Std of narrow-lane estimates are from 0.01 to 0.02 cycles. Secondly, many experiments have been conducted to investigate the CFR of integer ambiguity resolution we can achieve under different conditions, including reference station density, observation session length and the ionospheric activity. The results show that the CFR of PPP can exceed 98.0 % with only 1 h of observations for most user stations. No obvious correlation between the CFR and the reference station density is found. Therefore, nearly homogeneous CFR can be achieved in PPP AR for global users. At user end, higher CFR could be achieved with longer observations. The average CFR for 30-min, 1-h, 2-h and 4-h observation is 92.3, 98.2, 99.5 and 99.7 %, respectively. In order to get acceptable CFR, 1 h is a recommended minimum observation time. Furthermore, the CFR of PPP can be affected by diurnal variation and geomagnetic latitude variation in the ionosphere. During one day at the hours when rapid ionospheric variations occur or in low geomagnetic latitude regions where equatorial electron density irregularities are produced relatively frequently, a significant degradation of the CFR is demonstrated. Numéro de notice : A2013-341 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0632-5 Date de publication en ligne : 23/03/2013 En ligne : https://doi.org/10.1007/s00190-013-0632-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32479
in Journal of geodesy > vol 87 n° 6 (June 2013) . - pp 579 - 589[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2013061 SL Revue Centre de documentation Revues en salle Disponible Modeling ambiguity in census microdata allocations to improve demographic small area estimates / Stefan Leyk in Transactions in GIS, vol 17 n° 3 (June 2013)
[article]
Titre : Modeling ambiguity in census microdata allocations to improve demographic small area estimates Type de document : Article/Communication Auteurs : Stefan Leyk, Auteur ; Barbara P. Buttenfield, Auteur ; Nicholas N. Nagle, Auteur Année de publication : 2013 Article en page(s) : pp 406 - 425 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] allocation
[Termes IGN] données démographiques
[Termes IGN] estimation statistique
[Termes IGN] recensement démographique
[Termes IGN] résolution d'ambiguïté
[Termes IGN] spatial metricsRésumé : (Auteur) This article describes a methodology for allocating demographic microdata to small enumeration areas such as census tracts, in the presence of underlying ambiguities. Maximum Entropy methods impute population weights that are constrained to match a set of census tract-level summary statistics. Once allocated, the household characteristics are summarized to revise estimates of tract-level demographic summary statistics, and to derive measures of ambiguity. The revised summary statistics are compared with original tract summaries within a context of expected variation. Allocation ambiguity is quantified for each household as a function of the distribution of imputed sample weights over all census tracts, and by computed metrics of confusion and variety of allocation to any census tract. The process reported here allows differentiation of households with regard to inherent ambiguity in the allocation decision. Ambiguity assessment represents an important component that has been neglected in spatial allocation work to date but can be seen as important additional knowledge for demographers and users of small area estimates. For the majority of tested variables, the revised tract level summaries correlate highly with original tract summary statistics. In addition to assessments for individual households, it is also possible to compute average allocation ambiguity for individual tracts, and to associate this with demographic characteristics not utilized in the allocation process. Numéro de notice : A2013-291 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01366.x Date de publication en ligne : 07/01/2013 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01366.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32429
in Transactions in GIS > vol 17 n° 3 (June 2013) . - pp 406 - 425[article]A method for improving uncalibrated phase delay estimation and ambiguity-fixing in real-time precise point positioning / Xinging Li in Journal of geodesy, vol 87 n° 5 (May 2013)
[article]
Titre : A method for improving uncalibrated phase delay estimation and ambiguity-fixing in real-time precise point positioning Type de document : Article/Communication Auteurs : Xinging Li, Auteur ; Maorong Ge, Auteur Année de publication : 2013 Article en page(s) : pp 405 - 416 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] atténuation du signal
[Termes IGN] mesurage de phase
[Termes IGN] positionnement ponctuel précis
[Termes IGN] propagation ionosphérique
[Termes IGN] résolution d'ambiguïté
[Termes IGN] temps de propagation
[Termes IGN] temps réelRésumé : (Auteur) In order to improve the performance of precise point positioning (PPP), this paper presents a new data processing scheme to shorten the convergence time and the observation time required for a reliable ambiguity-fixing. In the new scheme, L1 and L2 raw observations are used and the slant ionospheric delays are treated as unknown parameters. The empirical spatial and temporal constraints and the ionospheric delays derived from a real-time available ionospheric model are all considered as pseudo-observations into the estimation for strengthening the solution. Furthermore, we develop a real-time computational procedure for generating uncalibrated phase delays (UPDs) on L1 and L2 frequencies. The PPP solution is first carried out on all reference stations based on the proposed scheme, undifferenced float ambiguities on L1 and L2 frequencies can be directly obtained from the new scheme. The L1 and L2 UPDs are then generated and broadcasted to users in real-time. This data product and also the performance of the new PPP scheme are evaluated. Our results indicate that the new processing scheme considering ionospheric characteristics can reduce the convergence time by about 30 % for float kinematic solutions. The observation time for a reliable ambiguity-fixing is shortened by 25 % compared to that of the traditional ambiguity-fixed kinematic solution. When the new method is used for static reference stations, the observation time for ambiguity-fixing is about 10 min in static mode and only 5 min if the coordinates are fixed to well-known values. Numéro de notice : A2013-251 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0611-x En ligne : https://doi.org/10.1007/s00190-013-0611-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32389
in Journal of geodesy > vol 87 n° 5 (May 2013) . - pp 405 - 416[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2013051 SL Revue Centre de documentation Revues en salle Disponible Triple-frequency GPS precise point positioning with rapid ambiguity resolution / Jianghui Geng in Journal of geodesy, vol 87 n° 5 (May 2013)
[article]
Titre : Triple-frequency GPS precise point positioning with rapid ambiguity resolution Type de document : Article/Communication Auteurs : Jianghui Geng, Auteur ; Yehuda Bock, Auteur Année de publication : 2013 Article en page(s) : 460 p. ; pp 449 - 460 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] modulation de fréquence
[Termes IGN] positionnement ponctuel précis
[Termes IGN] récepteur trifréquence
[Termes IGN] résolution d'ambiguïtéRésumé : (Auteur) At present, reliable ambiguity resolution in real-time GPS precise point positioning (PPP) can only be achieved after an initial observation period of a few tens of minutes. In this study, we propose a method where the incoming triple-frequency GPS signals are exploited to enable rapid convergences to ambiguity-fixed solutions in real-time PPP. Specifically, extra-wide-lane ambiguity resolution can be first achieved almost instantaneously with the Melbourne-Wübbena combination observable on L2 and L5. Then the resultant unambiguous extra-wide-lane carrier-phase is combined with the wide-lane carrier-phase on L1 and L2 to form an ionosphere-free observable with a wavelength of about 3.4 m. Although the noise of this observable is around 100 times the raw carrier-phase noise, its wide-lane ambiguity can still be resolved very efficiently, and the resultant ambiguity-fixed observable can assist much better than pseudorange in speeding up succeeding narrow-lane ambiguity resolution. To validate this method, we use an advanced hardware simulator to generate triple-frequency signals and a high-grade receiver to collect 1-Hz data. When the carrier-phase precisions on L1, L2 and L5 are as poor as 1.5, 6.3 and 1.5 mm, respectively, wide-lane ambiguity resolution can still reach a correctness rate of over 99 % within 20 s. As a result, the correctness rate of narrow-lane ambiguity resolution achieves 99 % within 65 s, in contrast to only 64 % within 150 s in dual-frequency PPP. In addition, we also simulate a multipath-contaminated data set and introduce new ambiguities for all satellites every 120 s. We find that when multipath effects are strong, ambiguity-fixed solutions are achieved at 78 % of all epochs in triple-frequency PPP whilst almost no ambiguities are resolved in dual-frequency PPP. Therefore, we demonstrate that triple-frequency PPP has the potential to achieve ambiguity-fixed solutions within a few minutes, or even shorter if raw carrier-phase precisions are around 1 mm. In either case, we conclude that the efficiency of ambiguity resolution in triple-frequency PPP is much higher than that in dual-frequency PPP. Numéro de notice : A2013-255 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0619-2 Date de publication en ligne : 22/02/2013 En ligne : https://doi.org/10.1007/s00190-013-0619-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32393
in Journal of geodesy > vol 87 n° 5 (May 2013) . - 460 p. ; pp 449 - 460[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2013051 SL Revue Centre de documentation Revues en salle Disponible Galileo altimetry using AltBOC and RTK techniques / Jürgen Dampf in Inside GNSS, vol 8 n° 1 (January - February 2013)PermalinkIntegration of galileo system in a positioning software, and estimation of Galileo system benefits / Laurane Boulanger (2013)PermalinkReliability of partial ambiguity fixing with multiple GNSS constellations / J. Wang in Journal of geodesy, vol 87 n° 1 (January 2013)PermalinkZero-difference GPS ambiguity resolution at CNES–CLS IGS Analysis Center / Sylvain Loyer in Journal of geodesy, vol 86 n° 11 (November 2012)PermalinkImproving the estimation of fractional-cycle biases for ambiguity resolution in precise point positioning / J. Geng in Journal of geodesy, vol 86 n° 8 (August 2012)PermalinkThe affine constrained GNSS attitude model and its multivariate integer least-squares solution / Peter J.G. Teunissen in Journal of geodesy, vol 86 n° 7 (July 2012)PermalinkRecent developments in Precise Point Positioning / Sunil Bisnath in Geomatica, vol 66 n° 2 (June 2012)PermalinkFast integer least-squares estimation for GNSS high-dimensional ambiguity resolution using lattice theory / S. Jazaeri in Journal of geodesy, vol 86 n° 2 (February 2012)PermalinkPermalinkAn evaluation of solar radiation pressure strategies for the GPS constellation / Ant Sibthorpe in Journal of geodesy, vol 85 n° 8 (August 2011)PermalinkRegional reference network augmented precise point positioning for instantaneous ambiguity resolution / X. Li in Journal of geodesy, vol 85 n° 3 (March 2011)PermalinkRapid re-convergences to ambiguity-fixed solutions in precise point positioning / J. Geng in Journal of geodesy, vol 84 n° 12 (December 2010)PermalinkRapid static positioning using GPS and GLONASS / Gerhard Beutler in Bulletin of geodesy and geomatics BGG, vol 69 n° 2 - 3 (December 2010)PermalinkFast GNSS ambiguity resolution as an ill-posed problem / Lard Erik Sjöberg in Journal of geodesy, vol 84 n° 11 (November 2010)PermalinkInteger ambiguity resolution in precise point positionning : method comparison / J. Geng in Journal of geodesy, vol 84 n° 9 (September 2010)PermalinkInteger least-squares theory for the GNSS compass / Peter J.G. Teunissen in Journal of geodesy, vol 84 n° 7 (July 2010)PermalinkSingle receiver phase ambiguity resolution with GPS data / Willy I. Bertiger in Journal of geodesy, vol 84 n° 5 (May 2010)PermalinkAutonomous integrity: an error isotropy-based approach for multiple fault conditions / M. Azaola-Saenz in Inside GNSS, Vol 4 n° 1 (January-Fabruary 2009)PermalinkGNSS three carrier ambiguity resolution using ionosphere-reduced virtual signals / Y. Feng in Journal of geodesy, vol 82 n° 12 (December 2008)PermalinkAmbiguity resolution in the air: mapping without stable GPS signals / J. Hutton in GIM international, vol 22 n° 11 (November 2008)Permalink