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Determination of Helmert transformation parameters for continuous GNSS networks: a case study of the Géoazur GNSS network / Dinh Trong Tran in Geo-spatial Information Science, vol 26 n° 1 (March 2023)  

Public [article]  inGeo-spatial Information Science > vol 26 n° 1 (March 2023) . - pp 125 - 138 Titre : Determination of Helmert transformation parameters for continuous GNSS networks: a case study of the Géoazur GNSS network Type de document : Article/Communication Auteurs : Dinh Trong Tran, Auteur ; Jean-Mathieu Nocquet , Auteur ; Ngoc Dung Luong, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : pp 125 - 138 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] données GNSS [Termes IGN] International Terrestrial Reference Frame [Termes IGN] méthode des moindres carrés [Termes IGN] transformation de coordonnées [Termes IGN] transformation de Helmert [Termes IGN] valeur aberrante Résumé : (auteur) In this paper, we propose an approach to determine seven parameters of the Helmert transformation by transforming the coordinates of a continuous GNSS network from the World Geodetic System 1984 (WGS84) to the International Terrestrial Reference Frame. This includes (1) converting the coordinates of common points from the global coordinate system to the local coordinate system, (2) identifying and eliminating outliers by the Dikin estimator, and (3) estimating seven parameters of the Helmert transformation by least squares (LS) estimation with the “clean” data (i.e. outliers removed). Herein, the local coordinate system provides a platform to separate points’ horizontal and vertical components. Then, the Dikin estimator identifies and eliminates outliers in the horizontal or vertical component separately. It is significant because common points in a continuous GNSS network may contain outliers. The proposed approach is tested with the Géoazur GNSS network with the results showing that the Dikin estimator detects outliers at 6 out of 18 common points, among which three points are found with outliers in the vertical component only. Thus, instead of eliminating all coordinate components of these six common points, we only eliminate all coordinate components of three common points and only the vertical component of another three common points. Finally, the classical LS estimation is applied to “clean” data to estimate seven parameters of the Helmert transformation with a significant accuracy improvement. The Dikin estimator’s results are compared to those of other robust estimators of Huber and Theil-Sen, which shows that the Dikin estimator performs better. Furthermore, the weighted total least-squares estimation is implemented to assess the accuracy of the LS estimation with the same data. The inter-comparison of the seven estimated parameters and their standard deviations shows a small difference at a few per million levels (E-6). Numéro de notice : A2023-208 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/10095020.2022.2138569 Date de publication en ligne : 15/11/2022 En ligne : https://doi.org/10.1080/10095020.2022.2138569 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103135 [article]

A new algebraic solution for transforming Cartesian to geodetic coordinates / Jia-Chun Guo in Survey review, vol 55 n° 389 (March 2023)  

Public [article]  inSurvey review > vol 55 n° 389 (March 2023) . - pp 169 - 177 Titre : A new algebraic solution for transforming Cartesian to geodetic coordinates Type de document : Article/Communication Auteurs : Jia-Chun Guo, Auteur ; Wenbin Shen, Auteur Année de publication : 2023 Article en page(s) : pp 169 - 177 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] calcul algébrique [Termes IGN] coordonnées cartésiennes [Termes IGN] coordonnées géodésiques [Termes IGN] système de coordonnées [Termes IGN] transformation de coordonnées Résumé : (auteur) An exact and stable algebraic solution based on solving a quartic equation with respect to the cosine function of the reduced latitude is proposed to transform Cartesian into geodetic coordinates. The unique proper root of the equation appropriate to the transformation is chosen from all possible roots by rigorous analyses and the singular region of the transformation that in which there at least one component of the geodetic coordinates is indeterminate or non-single-valued characteristics are determined strictly. The new algorithm does not need any approximation and the instability problems incurred in other algebraic solutions are overcome. For practical applications, the algorithm performs comparably to that of [Vermeille, H., 2011. An analytical method to transform geocentric into geodetic coordinates. Journal of geodesy, 85 (2), 105–117.] and shows a certain superiority in the singular disc over Vermeille's algorithm. Numéro de notice : A2023-135 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2022.2071055 Date de publication en ligne : 24/05/2022 En ligne : https://doi.org/10.1080/00396265.2022.2071055 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102686 [article]

Unification of GNSS CORS coordinates in Thailand / Somchai Kriengkraiwasin in Survey review, vol 54 n° 387 (November 2022)  

Public [article]  inSurvey review > vol 54 n° 387 (November 2022) . - pp 534 - 542 Titre : Unification of GNSS CORS coordinates in Thailand Type de document : Article/Communication Auteurs : Somchai Kriengkraiwasin, Auteur ; Chaiyut Charoenphon, Auteur ; Korakod Butwong, Auteur Année de publication : 2022 Article en page(s) : pp 534 - 542 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] International Terrestrial Reference Frame [Termes IGN] positionnement ponctuel précis [Termes IGN] réseau géodésique local [Termes IGN] réseau géodésique permanent [Termes IGN] station GNSS [Termes IGN] système de référence local [Termes IGN] Thaïlande [Termes IGN] transformation de coordonnées Résumé : (auteur) This study estimates station coordinates of GNSS CORS networks in Thailand, based on ITRF2014, by applying the Precise Point Positioning (PPP) technique computed by the GipsyX software. Datum transformation parameters between ITRF2005 and ITRF2014 were investigated to transform station coordinates from ITRF2005 to ITRF2014. The Molodensky-Badekas model provides more reliable results than the Bursa-Wolf model on these transformations. The accuracy of coordinate transformations can be increased by interpolating the remained residuals from transformed coordinates into grid residual corrections. The analyses show that the seven parameters with the grid residual corrections can significantly improve the accuracy of the coordinate transformation. Numéro de notice : A2022-898 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2021.1987002 Date de publication en ligne : 11/10/2022 En ligne : https://doi.org/10.1080/00396265.2021.1987002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102256 [article]

Using converted WW1 Army Grid Referencing Systems to identify locations where Australian soldiers fell Europe / Rodney Deakin in International journal of cartography, vol 8 n° 3 (November 2022)  

Public [article]  inInternational journal of cartography > vol 8 n° 3 (November 2022) . - pp 308 - 325 Titre : Using converted WW1 Army Grid Referencing Systems to identify locations where Australian soldiers fell Europe Type de document : Article/Communication Auteurs : Rodney Deakin, Auteur Année de publication : 2022 Article en page(s) : pp 308 - 325 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Projections [Termes IGN] Australie [Termes IGN] carte ancienne [Termes IGN] carte militaire [Termes IGN] carte topographique [Termes IGN] coordonnées géographiques [Termes IGN] Europe (géographie politique) [Termes IGN] Google Maps [Termes IGN] grille [Termes IGN] guerre [Termes IGN] projection conforme [Termes IGN] projection Universal Transverse Mercator [Termes IGN] transformation de coordonnées [Termes IGN] vingtième siècle Résumé : (auteur) Topographic maps (1:40,000) used by the British Army on the Western Front in World War 1 had a five-part Grid Reference System consisting of: (1) Map Number; (2) Letter-Square – 24 letter squaresA to X on each map; (3) Number-Square – 36 (and sometimes 30) 1000-yard squares in each letter square; (4) Minor-Square – four 500-yard squares denoted a, b, c, d in each number square; (5) Small-Square – 10 × 10 = 100 small-squares in a minor-square. Letter and number grid Woesten references (e.g. X: 28.A.6.b.73) cannot be used by modern GPS navigation devices that require geographical coordinates (latitude and longitude) or current map grid coordinates. This paper provides the background behind this project and demonstrates a method of transforming WW1 grid references to Universal Transverse Mercator (UTM) grid coordinates using Google Maps to obtain geographical coordinates, Geographic to UTM grid conversion and a 2D Conformal transformation. As well, it provides a ‘snapshot’ of practical methods that were used to develop a software package that would allow amateur military historians to convert the WW1 Grid Reference System to contemporary coordinates. Numéro de notice : A2022-748 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/23729333.2021.1877890 Date de publication en ligne : 13/05/2021 En ligne : https://doi.org/10.1080/23729333.2021.1877890 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101734 [article]

Partitions of normalised multiple regression equations for datum transformations / Andrew Carey Ruffhead in Boletim de Ciências Geodésicas, vol 28 n° 1 ([01/03/2022])  

Public [article]  inBoletim de Ciências Geodésicas > vol 28 n° 1 [01/03/2022] Titre : Partitions of normalised multiple regression equations for datum transformations Type de document : Article/Communication Auteurs : Andrew Carey Ruffhead, Auteur Année de publication : 2022 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] Australie occidentale (Australie) [Termes IGN] Grande-Bretagne [Termes IGN] régression multiple [Termes IGN] Slovénie [Termes IGN] transformation de coordonnées Résumé : (auteur) Multiple regression equations (MREs) provide an empirical direct method of transforming coordinates between geodetic datums. Since they offer a means of modelling distortions, they are capable of a more accurate fit to datum-shift datasets than more basic direct methods. MRE models of datum shifts traditionally consist of polynomials based on relative latitude and longitude. However, the limited availability of low-power terms often leads to high-power terms being included, and these are a potential cause of instability. This paper introduces three variations based on simple partitions and 2 or 4 smoothly conjoined polynomials. The new types are North/South, East/West and Four-Quadrant. They increase the availability of low-order terms, enabling distortions to be modelled with fewer side effects. Case studies in Great Britain, Slovenia and Western Australia provide examples of partitioned MREs that are more accurate than conventional MREs with the same number of terms. Numéro de notice : A2022-684 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueNat DOI : sans En ligne : https://revistas.ufpr.br/bcg/article/view/86199/46467 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101548 [article]

Bias in least-squares adjustment of implicit functional models / Michael Lösler in Survey review, Vol 53 n° 378 (May 2021)  

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Analytical and numerical methods of converting Cartesian to ellipsoidal coordinates / Georgios Panou in Journal of geodetic science, vol 11 n° 1 (January 2021)  

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Triangulation network of 1929–1944 of the first 1:500 urban map of València / Miriam Villar-Cano in Survey review, vol 52 n° 373 (July 2020)  

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The direct geodesic problem and an approximate analytical solution in Cartesian coordinates on a triaxial ellipsoid / Georgios Panou in Journal of applied geodesy, vol 14 n° 2 (April 2020)  

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Error propagation for the Molodensky G1 term / Jack C. McCubbine in Journal of geodesy, vol 93 n°6 (June 2019)  

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A bevy of area-preserving transforms for map projection designers / Daniel "daan" Strebe in Cartography and Geographic Information Science, vol 46 n° 3 (May 2019)  

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Integrated relative orientation based on point and line features via Plücker coordinates / Qinghong Sheng in Photogrammetric Engineering & Remote Sensing, PERS, vol 85 n° 4 (avril 2019)  

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Utilisation d’infrastructures géodésiques mondiales pour la réalisation nationale / Raphaël Legouge in XYZ, n° 158 (mars 2019)

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Geodesic equations and their numerical solution in Cartesian coordinates on a triaxial ellipsoid / Georgios Panou in Journal of geodetic science, vol 9 n° 1 (January 2019)  

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Geospatial analyses of Earth observation (EO) data / Antonio Pepe (2019)  

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