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Characterization of ionospheric variability in TEC using EOF and wavelets over low-latitude GNSS stations / J.R.K. Kumar Dabbakuti in Advances in space research, vol 57 n° 12 (June 2016)  

Public [article]  inAdvances in space research > vol 57 n° 12 (June 2016) . - pp 2427 – 2443 Titre : Characterization of ionospheric variability in TEC using EOF and wavelets over low-latitude GNSS stations Type de document : Article/Communication Auteurs : J.R.K. Kumar Dabbakuti, Auteur ; D. Venkata Ratman, Auteur Année de publication : 2016 Article en page(s) : pp 2427 – 2443 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] coordonnées GPS [Termes IGN] fonction orthogonale [Termes IGN] International Reference Ionosphere [Termes IGN] retard ionosphèrique [Termes IGN] teneur totale en électrons [Termes IGN] transformation en ondelettes Résumé : (auteur) Investigation of ionospheric variability is essential for improving the daily ionospheric modeling and forecasting services of Global Navigation Satellite System (GNSS) applications. As India is a low-latitude region, more care has to be taken here to characterize the ionosphere due to irregularities and Equatorial Ionization Anomaly (EIA) conditions. Therefore, an appropriate method is required to diagnose the ionospheric variations during geomagnetic, solar and other disturbances. In this paper, the temporal ionospheric time delay variations were studied based on the Empirical Orthogonal Function (EOF) analysis and wavelet transforms (WT).These analyses were carried out with Total Electron Content (TEC) datasets obtained from three GNSS stations located in low-latitude regions. EOF analysis was performed on the TEC datasets, which were decomposed into a time series of orthogonal eigen values (or base functions) and associated coefficients. EOF base functions and their associated coefficients signify the hourly time variations and the day of the year variations. The results reveal that the first few EOFs represented the majority of TEC variability pertaining to the physical processes of the ionosphere. The accuracy of the EOF model was validated by the evaluation of observational TEC data with International Reference Ionosphere (IRI) 2012 models. The EOF model coefficients for each GNSS station showed a strong correlation with the IRI models and also described the correlation between the impacts of the level of geomagnetic activity on the ionosphere. The correlation coefficients for the first three EOFs were more than 0.95. The phase relationship of ionospheric TEC anomalies, with respect to the geomagnetic indices (Dst), were analyzed by wavelet transforms. Numéro de notice : A2016-267 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.03.029 En ligne : https://doi.org/10.1016/j.asr.2016.03.029 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80802 [article]

There's an app for that : using a smartphone for GNSS ionospheric data collection / Andrew Kennedy in GPS world, vol 27 n° 6 (June 2016)  

Public [article]  inGPS world > vol 27 n° 6 (June 2016) . - pp 58 - 65 Titre : There's an app for that : using a smartphone for GNSS ionospheric data collection Type de document : Article/Communication Auteurs : Andrew Kennedy, Auteur ; Ryan Kingsbury, Auteur ; Anthea Coster, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 58 - 65 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] acquisition de données [Termes IGN] Androïd [Termes IGN] application informatique [Termes IGN] ionosphère [Termes IGN] récepteur GNSS [Termes IGN] téléphone intelligent [Termes IGN] teneur totale en électrons Résumé : (éditeur) [...] In this month’s column, we take a look at the use of a smartphone app to collect GNSS ionospheric data. Why would you want to do that? In the experience of the developers of the app, GNSS receivers are often characterized by a complex, proprietary data interface that differs for each manufacturer. In practice, this leads to significant investments in understanding interfaces and software tools. Human operators must familiarize themselves with the commands used to configure each receiver as well as with proprietary graphical user interfaces and tools specific to each receiver. The authors’ app-centric approach provides a software framework and output format that remain the same for different receivers. Receiver-specific commands are configurable within the app, so users can easily attach new receivers while reusing the existing infrastructures for data collection and processing. And smartphones have more than enough power and connectivity to do the job and can be easily moved from site to site. The smartphone as a handheld device to help scientists study the ionosphere? Probably not even Clive Sinclair foresaw that. Numéro de notice : A2016-333 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : http://gpsworld.com/innovation-theres-an-app-for-that/ Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80984 [article]

Evaluation of single frequency GPS precise point positioning assisted with external ionosphere sources / Reza Ghoddousi-Fard in Advances in space research, vol 57 n° 10 (May 2016)  

Public [article]  inAdvances in space research > vol 57 n° 10 (May 2016) . - pp 2154 - 2166 Titre : Evaluation of single frequency GPS precise point positioning assisted with external ionosphere sources Type de document : Article/Communication Auteurs : Reza Ghoddousi-Fard, Auteur ; François Lahaye, Auteur Année de publication : 2016 Article en page(s) : pp 2154 - 2166 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] couche atmosphérique [Termes IGN] ionosphère [Termes IGN] positionnement ponctuel précis [Termes IGN] récepteur bifréquence [Termes IGN] récepteur monofréquence [Termes IGN] teneur totale en électrons Résumé : (auteur) Single frequency code and single frequency code and phase GPS precise point positioning scenarios using various ionospheric sources are evaluated by assessing their performances with respect to dual frequency solutions. These include Canadian regional and global vertical total electron content (VTEC) maps produced by Natural Resources Canada and different International GNSS Service (IGS) coordination or analysis centres. Furthermore, two of the most commonly used single layer ionospheric mapping functions applied for conversion of VTEC to slant TEC are evaluated with each and every one of the ionospheric VTEC sources. Results show that the quality of code only solutions depends on ionospheric activity level, and the TEC map and mapping function selected. Code and phase single frequency solutions are also improved when assisted with an external ionosphere source. Numéro de notice : A2016-270 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.02.017 En ligne : http://dx.doi.org/10.1016/j.asr.2016.02.017 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80804 [article]

Reconstruction of the vertical electron density profile based on vertical TEC using the simulated annealing algorithm / Chunhua Jiang in Advances in space research, vol 57 n° 10 (May 2016)  

Public [article]  inAdvances in space research > vol 57 n° 10 (May 2016) . - pp 2167 - 2176 Titre : Reconstruction of the vertical electron density profile based on vertical TEC using the simulated annealing algorithm Type de document : Article/Communication Auteurs : Chunhua Jiang, Auteur ; Guo-Bin Yang, Auteur ; Peng Zhu, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 2167 - 2176 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] algorithme du recuit simulé [Termes IGN] modèle ionosphérique [Termes IGN] teneur totale en électrons [Termes IGN] teneur verticale totale en électrons Résumé : (auteur) This paper presents a new method to reconstruct the vertical electron density profile based on vertical Total Electron Content (TEC) using the simulated annealing algorithm. The present technique used the Quasi-parabolic segments (QPS) to model the bottomside ionosphere. The initial parameters of the ionosphere model were determined from both International Reference Ionosphere (IRI) (Bilitza et al., 2014) and vertical TEC (vTEC). Then, the simulated annealing algorithm was used to search the best-fit parameters of the ionosphere model by comparing with the GPS-TEC. The performance and robust of this technique were verified by ionosonde data. The critical frequency (foF2) and peak height (hmF2) of the F2 layer obtained from ionograms recorded at different locations and on different days were compared with those calculated by the proposed method. The analysis of results shows that the present method is inspiring for obtaining foF2 from vTEC. However, the accuracy of hmF2 needs to be improved in the future work. Numéro de notice : A2016-271 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.02.020 En ligne : http://dx.doi.org/10.1016/j.asr.2016.02.020 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80805 [article]

Determination of differential code biases with multi-GNSS observations / Ningbo Wang in Journal of geodesy, vol 90 n° 3 (March 2016)  

Public [article]  inJournal of geodesy > vol 90 n° 3 (March 2016) . - pp 209 - 228 Titre : Determination of differential code biases with multi-GNSS observations Type de document : Article/Communication Auteurs : Ningbo Wang, Auteur ; Yunbin Yuan, Auteur ; Zishen Li, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 209 - 228 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] code GNSS [Termes IGN] erreur systématique [Termes IGN] estimation de précision [Termes IGN] retard ionosphèrique [Termes IGN] teneur totale en électrons [Vedettes matières IGN] Traitement de données GNSS Résumé : (auteur) In order to better understand the differential code biases (DCBs) of global navigation satellite system, the IGGDCB method is extended to estimate the intra- and inter-frequency biases of the global positioning system (GPS), GLONASS, BeiDou navigation satellite system (BDS), and Galileo based on observations collected by the multi-GNSS experiment (MGEX) of the international GNSS service (IGS). In the approach of IGGDCB, the local ionospheric total electronic content is modeled with generalized triangular series (GTS) function rather than using a global ionosphere model or a priori ionospheric information. The DCB estimated by the IGGDCB method is compared with the DCB products from the Center for Orbit Determination in Europe (CODE) and German Aerospace Center (DLR), as well as the broadcast timing group delay (TGD) parameters over a 2-year span (2013 and 2014). The results indicate that GPS and GLONASS intra-frequency biases obtained in this work show the same precision levels as those estimated by DLR (about 0.1 and 0.2–0.4 ns for the two constellations, respectively, with respect to the products of CODE). The precision levels of IGGDCB-based inter-frequency biases estimated over the 24-month period are about 0.29 ns for GPS, 0.56 ns for GLONASS, 0.36 ns for BDS, and 0.24 ns for Galileo, respectively. Here, the accuracies of GPS and GLONASS biases are assessed relative to the products of CODE, while those of BDS and Galileo are compared with the estimates of DLR. In addition, the monthly stability indices of IGGDCB-based DCBs are 0.11 (GPS), 0.18 (GLONASS), 0.17 (BDS), and 0.14 (Galileo) ns for the individual constellation. Numéro de notice : A2016-246 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0867-4 Date de publication en ligne : 11/11/2015 En ligne : https://doi.org/10.1007/s00190-015-0867-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80752 [article]

Using ionospheric corrections from the space-based augmentation systems for low earth orbiting satellites / Jeongrae Kim in GPS solutions, vol 19 n° 3 (July 2015)  

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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)  

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Regional vertical total electron content (VTEC) modeling together with satellite and receiver differential code biases (DCBs) using semi-parametric multivariate adaptive regression B-splines (SP-BMARS) / Murat Durmaz in Journal of geodesy, vol 89 n° 4 (April 2015)  

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SHPTS: towards a new method for generating precise global ionospheric TEC map based on spherical harmonic and generalized trigonometric series functions / Zishen Li in Journal of geodesy, vol 89 n° 4 (April 2015)  

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Evaluation of Precise Point Positioning accuracy under large total electron content variations in equatorial latitudes / I. Rodriguez-Bilbao in Advances in space research, vol 55 n° 2 (January 2015)  

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Using DORIS measurements for modeling the vertical total electron content of the Earth’s ionosphere / Denise Dettmering in Journal of geodesy, vol 88 n° 12 (December 2014)  

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Application 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)  

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Climatological study of ionospheric irregularities over the European mid-latitude sector with GPS / Gilles Wautelet in Journal of geodesy, vol 88 n° 3 (March 2014)  

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Improved convergence for GNSS precise point positioning / Simon Banville (2014)  

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Performance evaluation of USTEC product for single-frequency precise point positioning / Mahmoud Abd-El-Rahman in Geomatica, vol 67 n° 4 (December 2013)  

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