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The triangulated affine transformation parameters and barycentric coordinates of Turkish Permanent GPS Network / Kutubuddin Ansari in Survey review, vol 50 n° 362 (August 2018)  

Public [article]  inSurvey review > vol 50 n° 362 (August 2018) . - pp 412 - 415 Titre : The triangulated affine transformation parameters and barycentric coordinates of Turkish Permanent GPS Network Type de document : Article/Communication Auteurs : Kutubuddin Ansari, Auteur ; Ozsen Corumluoglu, Auteur ; Payal Verma, Auteur Année de publication : 2018 Article en page(s) : pp 412 - 415 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] barycentre [Termes IGN] Eurasia Fixed Reference Frame [Termes IGN] réseau géodésique permanent [Termes IGN] transformation affine [Termes IGN] transformation de coordonnées [Termes IGN] Turquie Résumé : (Auteur) There are several computational approaches and methods to produce the complete solutions of geometry problems and they give sufficient computational strength for geodetic networks. Every approach and method has their advantages and drawbacks. Barycentric coordinates, also called areal coordinates, provide a new knock approach for geometry problems of such networks. This coordinate system offers triangular finite elements which are quite different from the usual Cartesian coordinate system. Actually, barycentric coordinates are a natural system of coordinates for the affine geometry. The modified approach for the affine transformation and barycentric coordinate system has been introduced and discussed, respectively in the study whether the affine transformation improves the results deteriorated by geometry of a GPS network. For this aim, general affine transformation of six-parameters between Eurasia Fixed Reference Frame (EUREF) and International Terrestrial Reference Frame (ITRF) for Turkish Permanent Global Positioning System Network (TPGN) has been computed. The affine transformation results show that the effects of the first and second translation parameters are in negative and positive directions, respectively. The third and sixth parameters are almost constant, on the other hand the fourth and fifth have a very small positive effect. Additionally, three triangular networks of GPS stations, at different locations in Turkey as a numerical example of barycentric coordinates, have also been presented. In the numerical example, the coordinate values of EUREF and ITRF have some differences after the decimal point, but the barycentric coordinates have very small amount of differences (sixth digit after decimal) which proves that the modified approach is meaningful. Numéro de notice : A2018-447 Affiliation des auteurs : non IGN Thématique : INFORMATIQUE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2017.1297016 Date de publication en ligne : 05/03/2017 En ligne : https://doi.org/10.1080/00396265.2017.1297016 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91032 [article]

On the determination of transformation parameters between different ITRS realizations using procrustes approach in Turkey / Mevlut Yetkin in Journal of applied geodesy, vol 11 n° 3 (September 2017)  

Public [article]  inJournal of applied geodesy > vol 11 n° 3 (September 2017) . - pp 123 - 130 Titre : On the determination of transformation parameters between different ITRS realizations using procrustes approach in Turkey Type de document : Article/Communication Auteurs : Mevlut Yetkin, Auteur ; Kutubuddin Ansari, Auteur Année de publication : 2017 Article en page(s) : pp 123 - 130 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] analyse procustéenne [Termes IGN] International Terrestrial Reference Frame [Termes IGN] réseau géodésique permanent [Termes IGN] transformation de coordonnées [Termes IGN] transformation de Helmert [Termes IGN] Turquie Résumé : (Auteur) The International Terrestrial Reference Frame (ITRF) solutions that are published by the International Earth Rotation and Reference Systems Service (IERS) are annual realizations of the ITRS (International Terrestrial Reference System). The results expressed in two different ITRS realizations can be compared using the transformation parameters that provide a link between different ITRF solutions. Generally, the 7-parameter (the three translation parameters, three rotation parameters and one scale factor) Helmert transformation is employed to compute the transformation parameters. However, the number of transformation parameters can be increased for better understanding. For example, 3 different scale factors may be computed instead of one scale factor. In this paper, the 9-parameter (the three translation parameters, three rotation parameters and three scale factors) transformation model and its solution by Procrustes approach is considered. Transformation parameters between ITRF 05 and ITRF 08 for Turkey have been computed in both 7-parameter model and 9-parameter model and a numerical example has been given to understand the difference between two models in a better way. An explanation about the proposed methodology as a flow chart also has been shown in appendix. Numéro de notice : A2017-567 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2016-0048 En ligne : https://doi.org/10.1515/jag-2016-0048 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86687 [article]

Monitoring and prediction of precipitable water vapor using GPS data in Turkey / Kutubuddin Ansari in Journal of applied geodesy, vol 10 n° 4 (December 2016)  

Public [article]  inJournal of applied geodesy > vol 10 n° 4 (December 2016) . - pp 233 – 245 Titre : Monitoring and prediction of precipitable water vapor using GPS data in Turkey Type de document : Article/Communication Auteurs : Kutubuddin Ansari, Auteur ; Omar F. Althuwaynee, Auteur ; Ozsen Corumluoglu, Auteur Année de publication : 2016 Article en page(s) : pp 233 – 245 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] analyse diachronique [Termes IGN] données météorologiques [Termes IGN] effet atmosphérique [Termes IGN] précipitation [Termes IGN] réfraction atmosphérique [Termes IGN] réseau géodésique permanent [Termes IGN] signal GPS [Termes IGN] température [Termes IGN] Turquie [Termes IGN] vapeur d'eau Résumé : (auteur) Although Global Positioning System (GPS) primarily provide accurate estimates of position, velocity and time of the receiver, as the signals pass through the atmoshphere carrying its signatures, thus offers opportunities for atmoshpheric applications. Precipitable water vapor (PWV) is a vital component of the atmosphere and significantly influences atmospheric processes like rainfall and atmospheric temperature. The developing networks of continuously operating GPS can be used to efficiently estimate PWV. The Turkish Permanent GPS Network (TPGN) is employed to monitor PWV information in Turkey. This work primarily aims to derive long-term data of PWV by using atmospheric path delays observed through continuously operating TPGN from November 2014 to October 2015. A least square mathematical approach was then applied to establish the relation of the observed PWV to rainfall and temperature. The modeled PWV was correlated with PWV estimated from GPS data, with an average correlation of 67.10 %–88.60 %. The estimated root mean square error (RMSE) varied from 2.840 to 6.380, with an average of 4.697. Finally, data of TPGN, rainfall, and temperature were obtained for less than 2 months (November 2015 to December 2015) and assessed to validate the mathematical model. This study provides a basis for determining PWV by using rainfall and temperature data. Numéro de notice : A206-973 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2016-0037 En ligne : https://doi.org/10.1515/jag-2016-0037 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83680 [article]