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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]An alternative ionospheric correction model for global navigation satellite systems / M.M. Hoque in Journal of geodesy, vol 89 n° 4 (April 2015)
[article]
Titre : An alternative ionospheric correction model for global navigation satellite systems Type de document : Article/Communication Auteurs : M.M. Hoque, Auteur ; Norbert Jakowski, Auteur Année de publication : 2015 Article en page(s) : pp 391 - 406 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] correction ionosphérique
[Termes IGN] ionosphère
[Termes IGN] modèle ionosphérique
[Termes IGN] propagation ionosphériqueRésumé : (auteur) The ionosphere is recognized as a major error source for single-frequency operations of global navigation satellite systems (GNSS). To enhance single-frequency operations the global positioning system (GPS) uses an ionospheric correction algorithm (ICA) driven by 8 coefficients broadcasted in the navigation message every 24 h. Similarly, the global navigation satellite system Galileo uses the electron density NeQuick model for ionospheric correction. The Galileo satellite vehicles (SVs) transmit 3 ionospheric correction coefficients as driver parameters of the NeQuick model. In the present work, we propose an alternative ionospheric correction algorithm called Neustrelitz TEC broadcast model NTCM-BC that is also applicable for global satellite navigation systems. Like the GPS ICA or Galileo NeQuick, the NTCM-BC can be optimized on a daily basis by utilizing GNSS data obtained at the previous day at monitor stations. To drive the NTCM-BC, 9 ionospheric correction coefficients need to be uploaded to the SVs for broadcasting in the navigation message. Our investigation using GPS data of about 200 worldwide ground stations shows that the 24-h-ahead prediction performance of the NTCM-BC is better than the GPS ICA and comparable to the Galileo NeQuick model. We have found that the 95 percentiles of the prediction error are about 16.1, 16.1 and 13.4 TECU for the GPS ICA, Galileo NeQuick and NTCM-BC, respectively, during a selected quiet ionospheric period, whereas the corresponding numbers are found about 40.5, 28.2 and 26.5 TECU during a selected geomagnetic perturbed period. However, in terms of complexity the NTCM-BC is easier to handle than the Galileo NeQuick and in this respect comparable to the GPS ICA. Numéro de notice : A2015-344 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0783-z Date de publication en ligne : 13/12/2014 En ligne : https://doi.org/10.1007/s00190-014-0783-z Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76716
in Journal of geodesy > vol 89 n° 4 (April 2015) . - pp 391 - 406[article]Assimilation of GRACE-derived oceanic mass distributions with a global ocean circulation model / J. Saynisch in Journal of geodesy, vol 89 n° 2 (February 2015)
[article]
Titre : Assimilation of GRACE-derived oceanic mass distributions with a global ocean circulation model Type de document : Article/Communication Auteurs : J. Saynisch, Auteur ; I. Bergmann–Wolf, Auteur ; M. Thomas, Auteur Année de publication : 2015 Article en page(s) : pp 121 - 139 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] anomalie de pesanteur
[Termes IGN] assimilation des données
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] correction atmosphérique
[Termes IGN] données GRACE
[Termes IGN] filtre de Kalman
[Termes IGN] masse d'eau
[Termes IGN] océan
[Termes IGN] océanographie spatialeRésumé : (auteur) To study the sub-seasonal distribution and generation of ocean mass anomalies, Gravity Recovery and Climate Experiment (GRACE) observations of daily and monthly resolution are assimilated into a global ocean circulation model with an ensemble-based Kalman-Filter technique. The satellite gravimetry observations are processed to become time-variable fields of ocean mass distribution. Error budgets for the observations and the ocean model’s initial state are estimated which contain the full covariance information. The consistency of the presented approach is demonstrated by increased agreement between GRACE observations and the ocean model. Furthermore, the simulations are compared with independent observations from 54 bottom pressure recorders. The assimilation improves the agreement to high-latitude recorders by up to 2 hPa. The improvements are caused by assimilation-induced changes in the atmospheric wind forcing, i.e., quantities not directly observed by GRACE. Finally, the use of the developed Kalman-Filter approach as a destriping filter to remove artificial noise contaminating the GRACE observations is presented Numéro de notice : A2015-332 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0766-0 Date de publication en ligne : 11/10/2014 En ligne : https://doi.org/10.1007/s00190-014-0766-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76657
in Journal of geodesy > vol 89 n° 2 (February 2015) . - pp 121 - 139[article]Generating statistically robust multipath stacking maps using congruent cells / Thomas Fuhrmann in GPS solutions, vol 19 n° 1 (January 2015)
[article]
Titre : Generating statistically robust multipath stacking maps using congruent cells Type de document : Article/Communication Auteurs : Thomas Fuhrmann, Auteur ; Xiaoguang Luo, Auteur ; Andreas Knöpfler, Auteur ; Michael Mayer, Auteur Année de publication : 2015 Article en page(s) : pp 83 - 92 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] congruence
[Termes IGN] correction du trajet multiple
[Termes IGN] résidu
[Termes IGN] superposition
[Termes IGN] trajet multiple
[Termes IGN] valeur aberranteRésumé : (auteur) Multipath effects caused by reflections in the near-field and far-field of a GNSS antenna represent a major error source in static and kinematic GNSS positioning applications. Since these effects are strongly site-specific, a generally valid and practicable analytical multipath model is still lacking. In contrast, using GNSS carrier phase observation residuals, the multipath stacking (MPS) methods are able to take site-specific conditions into account. We propose an advanced approach to performing residual-based MPS in the space domain. Being superior to most conventional attempts in which stacking cells have a fixed azimuthal resolution, our suggested method makes use of congruent cells and rigorous statistical assessments in terms of outlier detection and significance evaluation of the stacked values. The advanced stacking approach is applied to representative phase residuals from static precise point positioning. The results show that the use of congruent cells allows for MPS at high elevation angles and with a fine spatial resolution. Applying the resulting MPS maps at the residual level, both near-field and far-field effects at high and low elevation angles, respectively, can be significantly mitigated. In comparison with the conventional approach, the advanced one enables a larger reduction of about 20 % in the SD of residuals. Numéro de notice : A2015-205 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-014-0367-7 Date de publication en ligne : 23/02/2014 En ligne : https://doi.org/10.1007/s10291-014-0367-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76018
in GPS solutions > vol 19 n° 1 (January 2015) . - pp 83 - 92[article]The carrier-multipath observable: a new carrier-phase multipath mitigation technique / Ramin Moradi in GPS solutions, vol 19 n° 1 (January 2015)
[article]
Titre : The carrier-multipath observable: a new carrier-phase multipath mitigation technique Type de document : Article/Communication Auteurs : Ramin Moradi, Auteur ; Wolfgang Schuster, Auteur ; Shaojun Feng, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 73 - 82 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] correction du trajet multiple
[Termes IGN] trajet multipleRésumé : (auteur) Modeling and mitigating carrier-phase multipath errors continue to be a significant challenge for high-accuracy positioning using global navigation satellite systems. The multipath error is dependent on the operational environment and therefore cannot be mitigated by differencing techniques. The effect of multipath is accentuated when observables based on linear combinations of measurements from two or more frequencies are formulated. We develop a new carrier-phase multipath error observable that isolates the inter-frequency carrier-phase multipath error for linear combinations of observables, such as wide-lane (WL). Real-time kinematic positioning results from varying baseline lengths show that a significant reduction in between 14 and 47 % in the time to initial ambiguity resolution are achieved by correcting the WL observable using the new carrier-phase multipath error observable. Numéro de notice : A2015-204 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-014-0366-8 Date de publication en ligne : 22/01/2014 En ligne : https://doi.org/10.1007/s10291-014-0366-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76017
in GPS solutions > vol 19 n° 1 (January 2015) . - pp 73 - 82[article]Reducing distance dependent bias in low-cost single frequency GPS network to complement dual frequency GPS stations in order to derive detailed surface deformation field / H.-Y. Chen in Survey review, vol 47 n° 340 (January 2015)PermalinkTraitement de données Thematic Mapper pour la cartographie multi temporelle du plateau sous-marin autour des îles Kerkennah (Tunisie) / Rim Katlane in Photo interprétation, European journal of applied remote sensing, vol 50 n° 3 - 4 (septembre 2014)PermalinkLimnimétrie par réflectrométrie GNSS à faible coût / Eduardo Rodrigues in Géomatique suisse, vol 112 n° 8 (août 2014)PermalinkThe European way: Performance of the Galileo single-frequency ionospheric correction during in-orbit validation / Roberto Prieto-Cerdeira in GPS world, vol 25 n° 6 (June 2014)PermalinkApplication of SWACI products as ionospheric correction for single-point positioning: a comparative study / David Minkwitz in Journal of geodesy, vol 88 n° 5 (May 2014)PermalinkModeling and sensing the vertical structure of the atmospheric path delay by microwave radiometry to correct SAR interferograms / Patrizia Basili in IEEE Transactions on geoscience and remote sensing, vol 52 n° 2 (February 2014)PermalinkAtmospheric water vapour sensing by means of differential absorption spectrometry using solar and lunar radiation / Stefan Walter Münch (2014)PermalinkPermalinkPermalinkLocalisation de véhicule par satellites couplée à la navigation à l'estime et aux données cartographiques / David Bétaille (2014)Permalink