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Online precise point positioning: a new, timely service from Natural Resources Canada / Y. Mireault in GPS world, vol 19 n° 9 (September 2008)
[article]
Titre : Online precise point positioning: a new, timely service from Natural Resources Canada Type de document : Article/Communication Auteurs : Y. Mireault, Auteur ; P. Tetreault, Auteur ; François Lahaye, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 59 - 64 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] Canada
[Termes IGN] positionnement ponctuel précis
[Termes IGN] serveur web
[Termes IGN] temps réel
[Termes IGN] traitement de données GNSSRésumé : (Editeur) Meliora sequamur - let us strive to improve. The words that the Roman poet Virgil wrote some 2,000 years ago could well be the watchwords of those scientists and engineers who today work to improve the accuracy, coverage, and timeliness of GPS-based positioning. They are particularly appropriate for those seeking to improve the technique of precise point positioning or PPP. PPP is a single-receiver positioning technique just like conventional pseudorange-based positioning, which takes place inside a receiver. However, the similarity stops there. PPP uses the receiver's very precise undifferenced carrier-phase observations together with very precise (and accurate) satellite orbits and clocks to achieve positioning accuracies at the few centimeter level or better. And unlike differential techniques such as real-time kinematic (RTK) positioning, all of the physical phenomena affecting the measurements must be very accurately modeled. These include solid earth tides, ocean-tide loading, transmitting and receiving antenna phase-center offsets and variations, carrier-phase wind-up, relativistic effects, and so on. With differential techniques, such effects are greatly reduced and typically become insignificant, especially on short baselines. PPP can be used to process data collected at a fixed (static) site or along a trajectory in kinematic mode or a mixture of the two - "stop and go" PPP. Although introduced in the late 1990s, PPP has only become more commonplace in the past few years, thanks, in part, to continued PPP development in government and university research labs. Several PPP processors are even available online. The precise satellite orbits and clocks required are provided by the International GNSS Service (IGS) and its worldwide tracking network and analysis centers. These products are supplied with some latency resulting in PPP normally being used as a post-processing technique with observations being processed some time after they are collected. However, over the past year or so efforts have been made to reduce the latency of some high-precision products. In particular, the ultra-rapid orbit and clock product of the Geodetic Survey Division of Natural Resources Canada (NRCan) is now being produced with a delay of only 90 minutes. Coupled with NRCan's online PPP engine, it provides positioning accuracies almost as good as the IGS final product, which is only available with a delay of about two weeks. In this month's column, we take a look at this new, timely service from the Great White North. Copyright Questex Media Group Inc Numéro de notice : A2008-384 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29377
in GPS world > vol 19 n° 9 (September 2008) . - pp 59 - 64[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-08091 RAB Revue Centre de documentation En réserve L003 Disponible A systematic investigation of optimal carrier-phase combinations for modernized triple-frequency GPS / Marc Cocard in Journal of geodesy, vol 82 n° 9 (September 2008)
[article]
Titre : A systematic investigation of optimal carrier-phase combinations for modernized triple-frequency GPS Type de document : Article/Communication Auteurs : Marc Cocard, Auteur ; S. Bourgon, Auteur ; Omid Kamali, Auteur ; P. Collins, Auteur Année de publication : 2008 Article en page(s) : pp 555 - 564 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] ambiguïté entière
[Termes IGN] correction ionosphérique
[Termes IGN] matrice de covariance
[Termes IGN] méthode des moindres carrés
[Termes IGN] phase GPS
[Termes IGN] précision centimétrique
[Termes IGN] propagation ionosphérique
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal GPS
[Termes IGN] traitement de données GNSSRésumé : (Auteur) The upcoming modernization of the GPS signals will allow for measurements on an additional third frequency L5 located at 1176.45 MHz. To take advantage of carrier-phase measurements on this new signal, the strategies for integer ambiguity resolution, required for centimeter-level accuracy, may need to be revised. The Least-squares Ambiguity Decorrelation Adjustment method remains perhaps the most powerful tool for finding the best combinations based on a complete decorrelation of the variance–covariance matrix related to the ambiguities. However, the computational load of that method plus the opportunity to comprehensively study the interaction of multiple frequencies suggest a reconsideration of approaches using predefined combinations between frequencies is not out of place. In this paper a systematic investigation is made of all possible triple-frequency geometry-free carrier-phase combinations which retain the integer nature of the ambiguities. The concept of the lane-number is presented to unambiguously describe the wavelength of a particular combination. The propagation of the observation noise and of the ionospheric bias on these combinations is presented. These noise and ionospheric amplification factors are analysed with respect to the resulting wavelength, in an effort to highlight optimal combinations characterized by a long wavelength, low noise and limited ionospheric impact. Copyright Springer Numéro de notice : A2008-350 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0201-x En ligne : https://doi.org/10.1007/s00190-007-0201-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29343
in Journal of geodesy > vol 82 n° 9 (September 2008) . - pp 555 - 564[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-08081 RAB Revue Centre de documentation En réserve L003 Disponible 266-08082 RAB Revue Centre de documentation En réserve L003 Disponible The Bayesian detection of discontinuities in a polynomial regression and its application to the cycle-slip problem / M.C. DE Lacy in Journal of geodesy, vol 82 n° 9 (September 2008)
[article]
Titre : The Bayesian detection of discontinuities in a polynomial regression and its application to the cycle-slip problem Type de document : Article/Communication Auteurs : M.C. DE Lacy, Auteur ; M. Reguzzoni, Auteur ; Fernando Sanso, Auteur ; Giovanna Venuti, Auteur Année de publication : 2008 Article en page(s) : pp 527 - 542 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] Bernese
[Termes IGN] correction du signal
[Termes IGN] phase GNSS
[Termes IGN] Ploynôme
[Termes IGN] quantité discrète
[Termes IGN] régression
[Termes IGN] réseau bayesien
[Termes IGN] traitement de données GNSSRésumé : (Auteur) This paper deals with the problem of detecting and correcting cycle-slips in Global Navigation Satellite System (GNSS) phase data by exploiting the Bayesian theory. The method is here applied to undifferenced observations, because repairing cycle-slips already at this stage could be a useful pre-processing tool, especially for a network of permanent GNSS stations. If a dual frequency receiver is available, the cycle-slips can be easily detected by combining two phase observations or phase and range observations from a single satellite to a single receiver. These combinations, expressed in a distance unit form, are completely free from the geometry and depend only on the ionospheric effect, on the electronic biases and on the initial integer ambiguities; since these terms are expected to be smooth in time, at least in a short period, a cycle-slip in one or both the two carriers can be modelled as a discontinuity in a polynomial regression. The proposed method consists in applying the Bayesian theory to compute the marginal posterior distribution of the discontinuity epoch and to detect it as a maximum a posteriori (MAP) in a very accurate way. Concerning the cycle-slip correction, a couple of simultaneous integer slips in the two carriers is chosen by maximazing the conditional posterior distribution of the discontinuity amplitude given the detected epoch. Numerical experiments on simulated and real data show that the discontinuities with an amplitude 2 or 3 times larger than the noise standard deviation are successfully identified. This means that the Bayesian approach is able to detect and correct cycle-slips using undifferenced GNSS observations even if the slip occurs by one cycle. A comparison with the scientific software BERNESE 5.0 confirms the good performance of the proposed method, especially when data sampled at high frequency (e.g. every 1 s or every 5 s) are available. Copyright Springer Numéro de notice : A2008-349 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0203-8 En ligne : https://doi.org/10.1007/s00190-007-0203-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29342
in Journal of geodesy > vol 82 n° 9 (September 2008) . - pp 527 - 542[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-08081 RAB Revue Centre de documentation En réserve L003 Disponible 266-08082 RAB Revue Centre de documentation En réserve L003 Disponible The view from Chilbolton: in-orbit test results from the second Galileo satellite / G. Gatti in Inside GNSS, vol 3 n° 6 (September 2008)
[article]
Titre : The view from Chilbolton: in-orbit test results from the second Galileo satellite Type de document : Article/Communication Auteurs : G. Gatti, Auteur ; M. Falcone, Auteur ; V. Alpe, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : 6 p. ; pp 30 - 35 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] signal Galileo
[Termes IGN] test de performanceRésumé : (Editeur) Earlier this year, Galileo’s second experimental satellite reached orbit and began broadcasting a wide range of signals, including the first transmissions of the new composite BOC signal on the L1 frequency. This article provides an initial report of GIOVE-B observations performed at the Chilbolton Observatory in the United Kingdom, which confirm the basic soundness of the prototype Galileo navigation signals. Copyright Gibbons Media & Research LLC Numéro de notice : A2008-679 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33523
in Inside GNSS > vol 3 n° 6 (September 2008) . - 6 p. ; pp 30 - 35[article]Documents numériques
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The view from Chilbolton ... - pdf éditeurAdobe Acrobat PDF ADOP in closed form for a hierarchy of multi-frequency single-baseline GNSS models / Dennis Odijk in Journal of geodesy, vol 82 n° 8 (August 2008)
[article]
Titre : ADOP in closed form for a hierarchy of multi-frequency single-baseline GNSS models Type de document : Article/Communication Auteurs : Dennis Odijk, Auteur ; Peter J.G. Teunissen, Auteur Année de publication : 2008 Article en page(s) : pp 473 - 492 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] affaiblissement de la précision
[Termes IGN] ambiguïté entière
[Termes IGN] modèle de diffusion du rayonnement
[Termes IGN] positionnement par GNSS
[Termes IGN] propagation du signal
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal GNSSRésumé : (Auteur) Successful carrier phase ambiguity resolution is the key to high-precision positioning with Global Navigation Satellite Systems (GNSS). The ambiguity dilution of precision (ADOP) is a well-known scalar measure which can be used to infer the strength of the GNSS model for carrier phase ambiguity resolution. In this contribution we present analytical closed-form expressions for the ADOP. This will be done for a whole class of different multi- frequency single baseline models. These models include the geometry-fixed, the geometry-free and the geometry-based models, respectively. And within the class of geometry-based models, we discriminate between short and long observation time spans, and between stationary and moving receivers. The easy-to-use ADOP expressions can be applied to infer the contribution of various GNSS model factors. They comprise, for instance, the type, the number and the precision of the GNSS observations, the number and selection of frequencies, the presence of atmospheric disturbances, the length of the observation time span and the length of the baseline. Copyright Springer Numéro de notice : A2008-320 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-007-0197-2 En ligne : https://doi.org/10.1007/s00190-007-0197-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29313
in Journal of geodesy > vol 82 n° 8 (August 2008) . - pp 473 - 492[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-08071 RAB Revue Centre de documentation En réserve L003 Disponible 266-08072 RAB Revue Centre de documentation En réserve L003 Disponible GNSS indoors: fighting the fading, part 3 / Günter W. Hein in Inside GNSS, vol 3 n° 5 (July - August 2008)PermalinkResolution of GPS carrier-phase ambiguities in Precise Point Positioning (PPP) with daily observations / M. Ge in Journal of geodesy, vol 82 n° 7 (July 2008)PermalinkUplift and subsidence due to the 26 December 2004 Indonesian earthquake detected by SAR data / Marco Chini in International Journal of Remote Sensing IJRS, vol 29 n°13-14 (July 2008)PermalinkMulti-technique monitoring of ocean tide loading in Northern France / Muriel Llubes in Comptes rendus : Géoscience, vol 340 n° 6 (June 2010)PermalinkGIOVE-B on the ai r: understanding Galileo's new signals / G. Gao in Inside GNSS, vol 3 n° 4 (May - June 2008)PermalinkMaking a difference with GPS: time differences for kinematic positioning with low-cost receivers / J. Traugott in GPS world, vol 19 n° 5 (May 2008)PermalinkPermalinkA new method for three-carrier GNSS ambiguity resolution / U. Fernandez-Plazaola in Journal of geodesy, vol 82 n° 4-5 (April - May 2008)PermalinkAn empirical study of the effects of NLP components on Geographic IR performance / N. Stokes in International journal of geographical information science IJGIS, vol 22 n° 3 (march 2008)PermalinkA compression format and tools for GNSS observation data / Yuki Hatanaka in Bulletin of the Geographical survey institute, vol 55 (March 2008)Permalink