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Validation of regional and global ionosphere maps from GNSS measurements versus IRI2016 during different magnetic activity / Ahmed Sedeek in Journal of applied geodesy, vol 16 n° 3 (July 2022)  

Public [article]  inJournal of applied geodesy > vol 16 n° 3 (July 2022) . - pp 229 - 240 Titre : Validation of regional and global ionosphere maps from GNSS measurements versus IRI2016 during different magnetic activity Type de document : Article/Communication Auteurs : Ahmed Sedeek, Auteur Année de publication : 2022 Article en page(s) : pp 229 - 240 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Afrique du nord [Termes IGN] données GNSS [Termes IGN] harmonique sphérique [Termes IGN] International Reference Ionosphere [Termes IGN] interpolation [Termes IGN] Matlab [Termes IGN] modèle ionosphérique [Termes IGN] station GNSS [Termes IGN] teneur verticale totale en électrons Résumé : (auteur) This manuscript explores the divergence of the Vertical Total Electron Content (VTEC) estimated from Global Navigation Satellite System (GNSS) measurements using global, regional, and International Reference Ionosphere (IRI) models over low to high latitude regions during various magnetic activity. The VTEC is estimated using a territorial network consisting of 7 GNSS stations in Egypt and 10 GNSS stations from the International GNSS Service (IGS) Global network. The impact of magnetic activity on VTEC is investigated. Due to the deficiency of IGS receivers in north Africa and the shortage of GNSS measurements, an extra high interpolation is done to cover the deficit of data over North Africa. A MATLAB code was created to produce VTEC maps for Egypt utilizing a territorial network contrasted with global maps of VTEC, which are delivered by the Center for Orbit Determination in Europe (CODE). Thus we can have genuine VTEC maps estimated from actual GNSS measurements over any region of North Africa. A Spherical Harmonics Expansion (SHE) equation was modelled using MATLAB and called Local VTEC Model (LVTECM) to estimate VTEC values using observations of dual-frequency GNSS receivers. The VTEC calculated from GNSS measurement using LVTECM is compared with CODE VTEC results and IRI-2016 VTEC model results. The analysis of outcomes demonstrates a good convergence between VTEC from CODE and estimated from LVTECM. A strong correlation between LVTECM and CODE reaches about 96 % and 92 % in high and low magnetic activity, respectively. The most extreme contrasts are found to be 2.5 TECu and 1.3 TECu at high and low magnetic activity, respectively. The maximum discrepancies between LVTECM and IRI-2016 are 9.7 TECu and 2.3 TECu at a high and low magnetic activity. Variation in VTEC due to magnetic activity ranges from 1–5 TECu in moderate magnetic activity. The estimated VTEC from the regional network shows a 95 % correlation between the estimated VTEC from LVTECM and CODE with a maximum difference of 5.9 TECu. Numéro de notice : A2022-495 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2021-0046 Date de publication en ligne : 09/02/2022 En ligne : https://doi.org/10.1515/jag-2021-0046 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100985 [article]

Comparison of atmospheric mass density models using a new data source: COSMIC satellite ephemerides / Yang Yang in IEEE Aerospace and Electronic Systems Magazine, vol 37 n° 2 (February 2022)  

Public [article]  inIEEE Aerospace and Electronic Systems Magazine > vol 37 n° 2 (February 2022) . - pp 6 - 22 Titre : Comparison of atmospheric mass density models using a new data source: COSMIC satellite ephemerides Type de document : Article/Communication Auteurs : Yang Yang, Auteur ; Ronald Maj, Auteur ; Changyong He , Auteur ; Robert Norman, Auteur ; Emma Kerr, Auteur ; Brett Anthony Carter, Auteur ; Julie Louise Currie, Auteur ; Steve Gower, Auteur Année de publication : 2022 Projets : 2-Pas d'info accessible - article non ouvert / Article en page(s) : pp 6 - 22 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] analyse comparative [Termes IGN] atmosphère terrestre [Termes IGN] éphémérides de satellite [Termes IGN] International Reference Ionosphere [Termes IGN] masse d'air [Termes IGN] modèle atmosphérique [Termes IGN] orbite basse [Termes IGN] teneur totale en électrons Résumé : (auteur) Atmospheric mass density (AMD) plays a vital role in the drag calculation for space objects in low Earth orbit. Many empirical AMD models have been developed and used for orbit prediction and efforts continue to improve their accuracy in forecasting high-altitude atmospheric conditions. Previous studies have assessed these models at the height of 200 km to 600 km. In this paper, four state-of-the-art AMD models, i.e., MSISE90, MSISE00, JB2008 and DTM2013 are assessed for their orbit prediction (OP) capabilities by using a new data source of COSMIC satellite ephemerides at an orbital height of ~800 km, where the contribution of ions in the total AMD is more significant. A new testing model was developed by accounting for ion contribution based on the International Reference Ionosphere 2016 model, including many more ion species that are not accounted for in other AMD models. In the assessment, two periods of forty days were chosen in 2014-2015 and 2018-2019, representing solar maximum and minimum periods, respectively, to assess four existing AMD models and the proposed model. Thorough analyses were conducted to compare OP results using different AMD models with precise reference ephemerides of COSMIC satellites and based on various space weather indices. It is shown that the proposed model outperforms all other AMD models in terms of OP errors during the solar maximum period. During solar minimum, the drag acceleration is relatively small for COSMIC satellites. Assessment of all AMD models in the orbit prediction process tends to be contaminated by the remaining uncertainty sources, such as solar radiation pressure. Numéro de notice : A2022-070 Affiliation des auteurs : ENSG+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/MAES.2021.3125101 Date de publication en ligne : 20/12/2021 En ligne : https://doi.org/10.1109/MAES.2021.3125101 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99376 [article]

Voir aussi

• Comparison of atmospheric mass density models using a new data source: COSMIC satellite ephemerides / Yang Yang (2020)  

Advanced machine learning optimized by the genetic algorithm in ionospheric models using long-term multi-instrument observations / Wang Li in Remote sensing, vol 12 n° 5 (March 2020)  

Public [article]  inRemote sensing > vol 12 n° 5 (March 2020) . - n° 866 Titre : Advanced machine learning optimized by the genetic algorithm in ionospheric models using long-term multi-instrument observations Type de document : Article/Communication Auteurs : Wang Li, Auteur ; Dongsheng Zhao, Auteur ; Changyong He , Auteur ; Andong Hu, Auteur ; Kefei Zhang, Auteur Année de publication : 2020 Projets : 3-projet - voir note / Article en page(s) : n° 866 Note générale : bibliographie This research was funded by the National Natural Science Foundations of China, grant number 41730109, the Priority Academic Program Development of Jiangsu Higher Education Institutions (Surveying and Mapping) and the Jiangsu Dual Creative Talents and Jiangsu Dual Creative Teams Programme Projects awarded in 2017. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] algorithme génétique [Termes IGN] image Formosat/COSMIC [Termes IGN] International Reference Ionosphere [Termes IGN] modèle ionosphérique [Termes IGN] réseau neuronal artificiel [Termes IGN] teneur totale en électrons Résumé : (auteur) The ionospheric delay is of paramount importance to radio communication, satellite navigation and positioning. It is necessary to predict high-accuracy ionospheric peak parameters for single frequency receivers. In this study, the state-of-the-art artificial neural network (ANN) technique optimized by the genetic algorithm is used to develop global ionospheric models for predicting foF2 and hmF2. The models are based on long-term multiple measurements including ionospheric peak frequency model (GIPFM) and global ionospheric peak height model (GIPHM). Predictions of the GIPFM and GIPHM are compared with the International Reference Ionosphere (IRI) model in 2009 and 2013 respectively. This comparison shows that the root-mean-square errors (RMSEs) of GIPFM are 0.82 MHz and 0.71 MHz in 2013 and 2009, respectively. This result is about 20%–35% lower than that of IRI. Additionally, the corresponding hmF2 median errors of GIPHM are 20% to 30% smaller than that of IRI. Furthermore, the ANN models present a good capability to capture the global or regional ionospheric spatial-temporal characteristics, e.g., the equatorial ionization anomaly and Weddell Sea anomaly. The study shows that the ANN-based model has a better agreement to reference value than the IRI model, not only along the Greenwich meridian, but also on a global scale. The approach proposed in this study has the potential to be a new three-dimensional electron density model combined with the inclusion of the upcoming Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC-2) data. Numéro de notice : A2020-872 Affiliation des auteurs : ENSG+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/rs12050866 Date de publication en ligne : 07/03/2020 En ligne : https://doi.org/10.3390/rs12050866 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99659 [article]

Comparison of atmospheric mass density models using a new data source: COSMIC satellite ephemerides / Yang Yang (2020)  

Public contenu dans Earth and Space Science Open Archive ESSOAr / American Geophysical Union (2019)   Titre : Comparison of atmospheric mass density models using a new data source: COSMIC satellite ephemerides Type de document : Article/Communication Auteurs : Yang Yang, Auteur ; Ronald Maj, Auteur ; Changyong He , Auteur ; Robert Norman, Auteur ; Emma Kerr, Auteur ; Brett Anthony Carter, Auteur ; Julie Louise Currie, Auteur ; Steve Gower, Auteur Editeur : Washington DC [Etats-Unis] : Earth and Space Science Open Archive ESSOAr Année de publication : 2020 Note générale : bibliographie Submitted to Space Weather Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] atmosphère terrestre [Termes IGN] éphémérides de satellite [Termes IGN] International Reference Ionosphere [Termes IGN] masse d'air [Termes IGN] modèle atmosphérique [Termes IGN] orbite basse Résumé : (auteur) Atmospheric mass density (AMD) plays a vital role in the drag calculation for space objects in low Earth orbit (LEO). Many empirical AMD models have been developed and used for orbit prediction and efforts continue to improve their accuracy in forecasting high-altitude atmospheric conditions. Previous studies have assessed these models at the height of 200 km to 600 km. A new empirical AMD model, dubbed as the SERC model, was developed by accounting for ion contribution based on the International Reference Ionosphere 2016 model, including many more ions that are not accounted for in other AMD models. This new model has been assessed in orbit prediction by using a new data source of COSMIC satellite ephemerides at the height of 800 km, where the contribution of ions in the total AMD is more significant. More specifically, two periods of forty days were chosen in 2014--2015 and 2018--2019, representing the solar maximum and minimum periods, respectively, to assess the SERC model and four other state-of-the-art AMD models. Thorough analyses were conducted to compare OP results using different AMD models with precise reference ephemerides of COSMIC satellites and based on various space weather indices. It is indicated that the SERC model outperforms all other AMD models in terms of OP errors during the solar maximum period and yields comparable OP results during the solar minimum period. Numéro de notice : P2020-001 Affiliation des auteurs : ENSG+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Preprint nature-HAL : Préprint DOI : 10.1002/essoar.10502170.1 Date de publication en ligne : 09/02/2020 En ligne : https://doi.org/10.1002/essoar.10502170.1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97632

Voir aussi

• Comparison of atmospheric mass density models using a new data source: COSMIC satellite ephemerides / Yang Yang in IEEE Aerospace and Electronic Systems Magazine, vol 37 n° 2 (February 2022)  

Evaluation of the IRI-2016 and NeQuick electron content specification by COSMIC GPS radio occultation, ground-based GPS and Jason-2 joint altimeter/GPS observations / Iurii Cherniak in Advances in space research, vol 63 n° 6 (15 March 2019)  

Public [article]  inAdvances in space research > vol 63 n° 6 (15 March 2019) . - pp 1845 - 1859 Titre : Evaluation of the IRI-2016 and NeQuick electron content specification by COSMIC GPS radio occultation, ground-based GPS and Jason-2 joint altimeter/GPS observations Type de document : Article/Communication Auteurs : Iurii Cherniak, Auteur ; Irina Zakharenkova, Auteur Année de publication : 2019 Article en page(s) : pp 1845 - 1859 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] données altimétriques [Termes IGN] données GPS [Termes IGN] données Jason [Termes IGN] International Reference Ionosphere [Termes IGN] modèle ionosphérique [Termes IGN] plasmasphère [Termes IGN] teneur totale en électrons [Termes IGN] variation diurne Résumé : (Auteur) We examined performance of two empirical profile-based ionospheric models, namely IRI-2016 and NeQuick-2, in electron content (EC) and total electron content (TEC) representation for different seasons and levels of solar activity. We derived and analyzed EC estimates in several representative altitudinal intervals for the ionosphere and the plasmasphere from the COSMIC GPS radio occultation, ground-based GPS and Jason-2 joint altimeter/GPS observations. It allows us to estimate a quantitative impact of the ionospheric electron density profiles formulation in several altitudinal intervals and to examine the source of the model-data discrepancies of the EC specification from the bottom-side ionosphere towards the GPS orbit altitudes. The most pronounced model-data differences were found at the low latitude region as related to the equatorial ionization anomaly appearance. Both the IRI-2016 and NeQuick-2 models tend to overestimate the daytime ionospheric EC and TEC at low latitudes during all seasons of low solar activity. On the contrary, during high solar activity the model results underestimated the EC/TEC observations at low latitudes. We found that both models underestimated the EC for the topside ionosphere and plasmasphere regions for all levels of solar activity. For low solar activity, the underestimated EC from the topside ionosphere and plasmasphere can compensate the overestimation of the ionospheric EC and, consequently, can slightly decrease the resulted model overestimation of the ground-based TEC. For high solar activity, the underestimated EC from the topside ionosphere and plasmasphere leads to a strengthening of the model underestimation of the ground-based TEC values. We demonstrated that the major source of the model-data discrepancies in the EC/TEC domain comes from the topside ionosphere/plasmasphere system. Numéro de notice : A2019-171 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2018.10.036 Date de publication en ligne : 02/11/2018 En ligne : https://doi.org/10.1016/j.asr.2018.10.036 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92622 [article]

Determination of the ionospheric foF2 using a stand-alone GPS receiver / Dudy D Wijaya in Journal of geodesy, vol 91 n° 9 (September 2017)  

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Performance evaluation of ionospheric time delay forecasting models using GPS observations at a low-latitude station / G. Sivavaraprasad in Advances in space research, vol 60 n° 2 (15 July 2017)  

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Ionospheric error contribution to GNSS single-frequency navigation at the 2014 solar maximum / Raul Orus Perez in Journal of geodesy, vol 91 n° 4 (April 2017)  

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Ionospheric tomography using GNSS: multiplicative algebraic reconstruction technique applied to the area of Brazil / Fabricio Dos Santos Prol in GPS solutions, vol 20 n° 4 (October 2016)  

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A new computerized ionosphere tomography model using the mapping function and an application to the study of seismic-ionosphere disturbance / Jian Kong in Journal of geodesy, vol 90 n° 8 (August 2016)  

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Modeling of ionosphere time series using wavelet neural networks (case study: N-W of Iran) / Mir Reza Ghaffari Razin in Advances in space research, vol 58 n° 1 (July 2016)  

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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)  

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A technique for routinely updating the ITU-R database using radio occultation electron density profiles / Claudio Brunini in Journal of geodesy, vol 87 n° 9 (September 2013)  

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vol 85 n° 12 - December 2011 - Special issue : Ionosphere (Bulletin de Journal of geodesy) / M. Schmidt  

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The international reference ionosphere today and in the future / Dieter Bilitza in Journal of geodesy, vol 85 n° 12 (December 2011)  

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