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Divisional ambiguity resolution for long range reference stations in network RTK / J. Deng in Survey review, vol 47 n° 343 (July 2015)
[article]
Titre : Divisional ambiguity resolution for long range reference stations in network RTK Type de document : Article/Communication Auteurs : J. Deng, Auteur ; S.L. Wang, Auteur Année de publication : 2015 Article en page(s) : pp 272 - 278 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] analyse comparative
[Termes IGN] fractionnement
[Termes IGN] ligne de base
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] résolution d'ambiguïté
[Termes IGN] station permanenteRésumé : (auteur) Increasing the distance between reference stations of network RTK can improve the flexibility of the reference stations sitting, reduce the number of reference stations and cut down construction and maintenance costs. However, it also decreases the correlation of spatial error and affects the real time performance and effectiveness of the network RTK positioning. Thus, the key techniques of long range network RTK need to be further optimised. Ambiguity resolution between reference stations is one of the most critical techniques. In this paper a divisional ambiguity resolution for long range reference stations of network RTK is proposed, so as to deal with the long fixed time and low success rate, especially for low elevation satellites. Based on conventional two-step ambiguity resolution, firstly, this new method calculates the wide-lane ambiguity by building M-W combination of pseudo-range and carrier observations. Second, the conventional ambiguity resolution as a whole is changed and satellites are divided into high elevation ones and low elevation ones, then the integer ambiguity of high elevation satellites is resolved by means of ionosphere-free combination with the relative zenith wet delay as a parameter. Finally, the Kalman filter model is established by the observation equation of high elevation satellites with calculated ambiguity and low elevation satellites, assisting to obtain the ambiguity of low elevation satellites quickly. The example selects a 196 km long baseline for comparative analysis. Result shows that it takes 733 s to resolve the ambiguity of all satellites by conventional ambiguity resolution in whole, and 252 s by divisional ambiguity resolution proposed in this paper. The new method saves about two thirds of resolution time, and also greatly improves the efficiency of ambiguity resolution of low elevation satellites for long baseline. Numéro de notice : A2015-921 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1179/1752270614Y.0000000123 En ligne : https://doi.org/10.1179/1752270614Y.0000000123 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79732
in Survey review > vol 47 n° 343 (July 2015) . - pp 272 - 278[article]Ionospheric 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)
[article]
Titre : Ionospheric effects in uncalibrated phase delay estimation and ambiguity-fixed PPP based on raw observable model Type de document : Article/Communication Auteurs : Shengfeng Gu, Auteur ; Chuang Shi, Auteur ; Yidong Lou, Auteur ; Jingnan Liu, Auteur Année de publication : 2015 Article en page(s) : pp 447 - 457 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] correction ionosphérique
[Termes IGN] modèle ionosphérique
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement ponctuel précis
[Termes IGN] propagation ionosphérique
[Termes IGN] résolution d'ambiguïté
[Termes IGN] retard ionosphèrique
[Termes IGN] signal GNSS
[Termes IGN] teneur totale en électronsRésumé : (auteur) Zero-difference (ZD) ambiguity resolution (AR) reveals the potential to further improve the performance of precise point positioning (PPP). Traditionally, PPP AR is achieved by Melbourne–Wübbena and ionosphere-free combinations in which the ionosphere effect are removed. To exploit the ionosphere characteristics, PPP AR with L1 and L2 raw observable has also been developed recently. In this study, we apply this new approach in uncalibrated phase delay (UPD) generation and ZD AR and compare it with the traditional model. The raw observable processing strategy treats each ionosphere delay as an unknown parameter. In this manner, both a priori ionosphere correction model and its spatio-temporal correlation can be employed as constraints to improve the ambiguity resolution. However, theoretical analysis indicates that for the wide-lane (WL) UPD retrieved from L1/L2 ambiguities to benefit from this raw observable approach, high precision ionosphere correction of better than 0.7 total electron content unit (TECU) is essential. This conclusion is then confirmed with over 1 year data collected at about 360 stations. Firstly, both global and regional ionosphere model were generated and evaluated, the results of which demonstrated that, for large-scale ionosphere modeling, only an accuracy of 3.9 TECU can be achieved on average for the vertical delays, and this accuracy can be improved to about 0.64 TECU when dense network is involved. Based on these ionosphere products, WL/narrow-lane (NL) UPDs are then extracted with the raw observable model. The NL ambiguity reveals a better stability and consistency compared to traditional approach. Nonetheless, the WL ambiguity can be hardly improved even constrained with the high spatio-temporal resolution ionospheric corrections. By applying both these approaches in PPP-RTK, it is interesting to find that the traditional model is more efficient in AR as evidenced by the shorter time to first fix, while the three-dimensional positioning accuracy of the RAW model outperforms the combination model by about 7.9%. This reveals that, with the current ionosphere models, there is actually no optimal strategy for the dual-frequency ZD ambiguity resolution, and the combination approach and raw approach each has merits and demerits. Numéro de notice : A2015-345 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0789-1 Date de publication en ligne : 15/02/2015 En ligne : https://doi.org/10.1007/s00190-015-0789-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76717
in Journal of geodesy > vol 89 n° 5 (May 2015) . - pp 447 - 457[article]Carrier-phase ambiguity resolution: Handling the biases for improved triple-frequency PPP convergence / Denis Laurichesse in GPS world, vol 26 n° 4 (April 2015)
[article]
Titre : Carrier-phase ambiguity resolution: Handling the biases for improved triple-frequency PPP convergence Type de document : Article/Communication Auteurs : Denis Laurichesse, Auteur Année de publication : 2015 Article en page(s) : pp 42 - 49 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] convergence
[Termes IGN] erreur systématique
[Termes IGN] onde porteuse
[Termes IGN] phase
[Termes IGN] phase GPS
[Termes IGN] positionnement différentiel
[Termes IGN] positionnement ponctuel précis
[Termes IGN] récepteur trifréquence
[Termes IGN] résolution d'ambiguïtéRésumé : (éditeur) [...] The other precision of PPP is its use of carrier-phase measurements rather than just pseudoranges. Carrier-phase measurements have a precision on the order of two magnitudes (a factor of 100) better than that of pseudoranges. But there is a catch to the use of carrier-phase measurements: they are ambiguous by an integer multiple of one cycle. Processing algorithms must resolve the value of this ambiguity and ideally fix it at its correct integer value. Unfortunately, it is difficult to do this instantaneously, and often many epochs of measurements are needed for a position solution to converge to a sufficiently high accuracy, say better than 10 centimeters. Researchers are actively working on reducing the convergence time, and this month'column, we look at how using measurements from three satellite frequencies rather than just two can help. Numéro de notice : A2015-092 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : http://gpsworld.com/innovation-carrier-phase-ambiguity-resolution/ Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75588
in GPS world > vol 26 n° 4 (April 2015) . - pp 42 - 49[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-2015041 RAB Revue Centre de documentation En réserve L003 Disponible Review and principles of PPP-RTK methods / Peter J.G. Teunissen in Journal of geodesy, vol 89 n° 3 (March 2015)
[article]
Titre : Review and principles of PPP-RTK methods Type de document : Article/Communication Auteurs : Peter J.G. Teunissen, Auteur ; Amir Khodabandeh, Auteur Année de publication : 2015 Article en page(s) : pp 217 - 240 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] analyse comparative
[Termes IGN] double différence
[Termes IGN] estimateur
[Termes IGN] méthode de mesure
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement ponctuel précis
[Termes IGN] résolution d'ambiguïtéRésumé : (auteur) PPP-RTK is integer ambiguity resolution-enabled precise point positioning. In this contribution, we present the principles of PPP-RTK, together with a review of different mechanizations that have been proposed in the literature. By application of S-system theory, the estimable parameters of the different methods are identified and compared. Their interpretation is essential for gaining a proper insight into PPP-RTK in general, and into the role of the PPP-RTK corrections in particular. We show that PPP-RTK is a relative technique for which the ‘single-receiver user’ integer ambiguities are in fact double-differenced ambiguities. We determine the transformational links between the different methods and their PPP-RTK corrections, thereby showing how different PPP-RTK methods can be mixed between network and users. We also present and discuss four different estimators of the PPP-RTK corrections. It is shown how they apply to the different PPP-RTK models, as well as why some of the proposed estimation methods cannot be accepted as PPP-RTK proper. We determine analytical expressions for the variance matrices of the ambiguity-fixed and ambiguity-float PPP-RTK corrections. This gives important insight into their precision, as well as allows us to discuss which parts of the PPP-RTK correction variance matrix are essential for the user and which are not. Numéro de notice : A2015-336 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0771-3 Date de publication en ligne : 13/11/2014 En ligne : https://doi.org/10.1007/s00190-014-0771-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76704
in Journal of geodesy > vol 89 n° 3 (March 2015) . - pp 217 - 240[article]An enhanced strategy for GNSS data processing of massive networks / H. Chen in Journal of geodesy, vol 88 n° 9 (September 2014)
[article]
Titre : An enhanced strategy for GNSS data processing of massive networks Type de document : Article/Communication Auteurs : H. Chen, Auteur ; W. Jiang, Auteur ; Maorong Ge, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 857-867 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] longueur d'onde
[Termes IGN] phase GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] résolution d'ambiguïtéRésumé : (Auteur)Although the computational burden of global navigation satellite systems (GNSS) data processing is nowadays already a big challenge, especially for huge networks, integrated processing of denser networks with data of multi-GNSS and multi-frequency is desired in the expectation of more accurate and reliable products. Based on the concept of carrier range, in this study, the precise point positioning with integer ambiguity resolution is engaged to obtain the integer ambiguities for converting carrier phases to carrier ranges. With such carrier ranges and pseudo-ranges, rigorous integrated processing is realized computational efficiently for the orbit and clock estimation using massive networks. The strategy is validated in terms of computational efficiency and product quality using data of the IGS network with about 460 stations. The experimental validation shows that the computation time of the new strategy increases gradually with the number of stations. It takes about 14 min for precise orbit and clock determination with 460 stations, while the current strategy needs about 82 min. The overlapping orbit RMS is reduced from 27.6 mm with 100 stations to 24.8 mm using the proposed strategy, and the RMS could be further reduced to 23.2 mm by including all 460 stations. Therefore, the new strategy could be applied to massive networks of multi-GNSS and multi-frequency receivers and possibly to achieve GNSS data products of higher quality. Numéro de notice : A2013-546 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0727-7 Date de publication en ligne : 05/06/2014 En ligne : https://doi.org/10.1007/s00190-014-0727-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74028
in Journal of geodesy > vol 88 n° 9 (September 2014) . - pp 857-867[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2014091 SL Revue Centre de documentation Revues en salle Disponible Generalized integer aperture estimation for partial GNSS ambiguity fixing / Andreas Brack in Journal of geodesy, vol 88 n° 5 (May 2014)PermalinkGNSS antenna array-aided CORS ambiguity resolution / Bofeng Li in Journal of geodesy, vol 88 n° 4 (April 2014)PermalinkInstantaneous BeiDou+GPS RTK positioning with high cut-off elevation angles / Peter J.G. Teunissen in Journal of geodesy, vol 88 n° 4 (April 2014)PermalinkGNSS ambiguity resolution with controllable failure rate for long baseline network RTK / Bofeng Li in Journal of geodesy, vol 88 n° 2 (February 2014)PermalinkPrecise position determination using a Galileo E5 single-frequency receiver / H. Toho Diessongo in GPS solutions, vol 18 n° 1 (january 2014)PermalinkAmbiguity 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)PermalinkAssessment 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)PermalinkModeling ambiguity in census microdata allocations to improve demographic small area estimates / Stefan Leyk in Transactions in GIS, vol 17 n° 3 (June 2013)PermalinkA 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)PermalinkTriple-frequency GPS precise point positioning with rapid ambiguity resolution / Jianghui Geng in Journal of geodesy, vol 87 n° 5 (May 2013)Permalink