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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)
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 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 aberranteRésumé : (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
in Geo-spatial Information Science > vol 26 n° 1 (March 2023) . - pp 125 - 138[article]
Titre : Conformal cylindrical properties of Adriatic Sea basin renderings on portolan charts Type de document : Article/Communication Auteurs : Tome Marelić, Auteur Année de publication : 2022 Article en page(s) : pp 83 - 101 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Projections
[Termes IGN] Adriatique, mer
[Termes IGN] modèle géométrique
[Termes IGN] portulan
[Termes IGN] projection conforme cylindrique
[Termes IGN] projection Universal Transverse Mercator
[Termes IGN] transformation de HelmertRésumé : (auteur) The geometry of Adriatic Sea basin renderings on 12 portolan charts made from the late thirteenth to the late sixteenth century was compared to a modern map by applying Helmert transformation in order to preserve their initial geometry and by using the same 40 identical points per chart. In the first stage of the research, the geometry of the portolan charts was compared to six selected map projections in order to determine the geometrical ‘best fit'. In the second stage, networks of lines plotted on charts were divided regionally and functionally and compared to the ‘best fit’ map projection to determine their geometric patterns in more detail. The research results showed that Adriatic Sea basin renderings on portolan charts were probably the result of a deliberately applied map projection which was geometrically most similar to the modern conformal cylindrical (Mercator) projection. Numéro de notice : A2022-862 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/POSITIONNEMENT Nature : Article DOI : 10.1080/00087041.2021.1956263 Date de publication en ligne : 11/03/2022 En ligne : https://doi.org/10.1080/00087041.2021.1956263 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102278
in Cartographic journal (the) > vol 59 n° 2 (May 2022) . - pp 83 - 101[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 030-2022021 RAB Revue Centre de documentation En réserve L003 Disponible 
Titre : Feature matching for multi-epoch historical aerial images Type de document : Article/Communication Auteurs : Lulin Zhang Année de publication : 2021 Article en page(s) : pp 176 - 189 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] appariement de données localisées
[Termes IGN] chaîne de traitement
[Termes IGN] géoréférencement indirect
[Termes IGN] image ancienne
[Termes IGN] image multitemporelle
[Termes IGN] image RVB
[Termes IGN] méthode robuste
[Termes IGN] MicMac
[Termes IGN] modèle numérique de surface
[Termes IGN] orientation relative
[Termes IGN] point d'appui
[Termes IGN] transformation de HelmertRésumé : (auteur) Historical imagery is characterized by high spatial resolution and stereoscopic acquisitions, providing a valuable resource for recovering 3D land-cover information. Accurate geo-referencing of diachronic historical images by means of self-calibration remains a bottleneck because of the difficulty to find sufficient amount of feature correspondences under evolving landscapes. In this research, we present a fully automatic approach to detecting feature correspondences between historical images taken at different times (i.e., inter-epoch), without auxiliary data required. Based on relative orientations computed within the same epoch (i.e., intra-epoch), we obtain DSMs (Digital Surface Model) and incorporate them in a rough-to-precise matching. The method consists of: (1) an inter-epoch DSMs matching to roughly co-register the orientations and DSMs (i.e, the 3D Helmert transformation), followed by (2) a precise inter-epoch feature matching using the original RGB images. The innate ambiguity of the latter is largely alleviated by narrowing down the search space using the co-registered data. With the inter-epoch feature correspondences, we refine the image orientations and quantitatively evaluate the results (1) with DoD (Difference of DSMs), (2) with ground check points, and (3) by quantifying ground displacement due to an earthquake. We demonstrate that our method: (1) can automatically georeference diachronic historical images; (2) can effectively mitigate systematic errors induced by poorly estimated camera parameters; (3) is robust to drastic scene changes. Compared to the state-of-the-art, our method improves the image georeferencing accuracy by a factor of 2. The proposed methods are implemented in MicMac, a free, open-source photogrammetric software. Numéro de notice : A2021-781 Affiliation des auteurs : UGE-LASTIG (2020- ) Thématique : IMAGERIE/INFORMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2021.10.008 Date de publication en ligne : 01/11/2021 En ligne : https://doi.org/10.1016/j.isprsjprs.2021.10.008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98933
in ISPRS Journal of photogrammetry and remote sensing > Vol 182 (December 2021) . - pp 176 - 189[article]Exemplaires(3)
Code-barres Cote Support Localisation Section Disponibilité 081-2021121 SL Revue Centre de documentation Revues en salle Disponible 081-2021123 DEP-RECP Revue LASTIG Dépôt en unité Exclu du prêt 081-2021122 DEP-RECF Revue Nancy Dépôt en unité Exclu du prêt Documents numériques
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Titre : Benefits of non-tidal loading applied at distinct levels in VLBI analysis Type de document : Article/Communication Auteurs : Matthias Glomsda, Auteur ; Mathis Blossfeld, Auteur ; Manuela Seitz, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : n° 90 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données ITGB
[Termes IGN] effet de charge
[Termes IGN] interférométrie à très grande base
[Termes IGN] pesanteur hors marée
[Termes IGN] retard troposphérique
[Termes IGN] série temporelle
[Termes IGN] surcharge hydrologique
[Termes IGN] surcharge océanique
[Termes IGN] transformation de HelmertRésumé : (auteur) In the analysis of very long baseline interferometry (VLBI) observations, many geophysical models are used for correcting the theoretical signal delay. In addition to the conventional models described by Petit and Luzum (eds) (IERS Conventions, 2010), we are applying different parts of non-tidal site loading, namely the atmospheric, oceanic, and hydrological ones. To investigate their individual contributions, these parts are considered both separately and combined to a total loading. The application of the corresponding site displacements is performed at two distinct levels of the geodetic parameter estimation process (observation and normal equation level), which turn out to give very similar results in many cases. To validate our findings internally, the site displacements are provided by two different data centres: the Earth-System-Modelling group at the Deutsches GeoForschungsZentrum in Potsdam (ESMGFZ, see Dill and Dobslaw, J Geophys Res Solid Earth, 2013. https://doi.org/10.1002/jgrb.50353ISTEX)] and the International Mass Loading Service [IMLS, see Petrov (The international mass loading service, 2015)]. We show that considering non-tidal loading is actually useful for mitigating systematic effects in the VLBI results, like annual signals in the station height time series. If the sum of all non-tidal loading parts is considered, the WRMS of the station heights and baseline lengths is reduced in 80–90% of all cases, and the relative improvement is about −3.5% on average. The main differences between our chosen providers originate from hydrological loading. Numéro de notice : A2020-540 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01418-z Date de publication en ligne : 31/08/2020 En ligne : https://doi.org/10.1007/s00190-020-01418-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95741
in Journal of geodesy > vol 94 n° 9 (September 2020) . - n° 90[article]
Titre : Impact of network constraining on the terrestrial reference frame realization based on SLR observations to LAGEOS Type de document : Article/Communication Auteurs : Radoslaw Zajdel, Auteur ; Krzysztof Sosnica, Auteur ; Mateusz Drożdżewski, Auteur ; Grzegorz Bury, Auteur ; D. Strugarek, Auteur Année de publication : 2019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] géocentre
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] Lageos
[Termes IGN] réseau de contraintes
[Termes IGN] rotation de la Terre
[Termes IGN] station TLS (télémétrie)
[Termes IGN] système de référence géodésique
[Termes IGN] système de référence local
[Termes IGN] télémétrie laser sur satellite
[Termes IGN] transformation de HelmertRésumé : (auteur)
The Satellite Laser Ranging (SLR) network struggles with some major limitations including an inhomogeneous global station distribution and uneven performance of SLR sites. The International Laser Ranging Service (ILRS) prepares the time-variable list of the most well-performing stations denoted as ‘core sites’ and recommends using them for the terrestrial reference frame (TRF) datum realization in SLR processing. Here, we check how different approaches of the TRF datum realization using minimum constraint conditions (MCs) and the selection of datum-defining stations affect the estimated SLR station coordinates, the terrestrial scale, Earth rotation parameters (ERPs), and geocenter coordinates (GCC). The analyses are based on the processing of the SLR observations to LAGEOS-1/-2 collected between 2010 and 2018. We show that it is essential to reject outlying stations from the reference frame realization to maintain a high quality of SLR-based products. We test station selection criteria based on the Helmert transformation of the network w.r.t. the a priori SLRF2014 coordinates to reject misbehaving stations from the list of datum-defining stations. The 25 mm threshold is optimal to eliminate the epoch-wise temporal deviations and to provide a proper number of datum-defining stations. According to the station selection algorithm, we found that some of the stations that are not included in the list of ILRS core sites could be taken into account as potential core stations in the TRF datum realization. When using a robust station selection for the datum definition, we can improve the station coordinate repeatability by 8%, 4%, and 6%, for the North, East and Up components, respectively. The global distribution of datum-defining stations is also crucial for the estimation of ERPs and GCC. When excluding just two core stations from the SLR network, the amplitude of the annual signal in the GCC estimates is changed by up to 2.2 mm, and the noise of the estimated pole coordinates is substantially increased.Numéro de notice : A2019-610 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-019-01307-0 Date de publication en ligne : 17/10/2019 En ligne : https://doi.org/10.1007/s00190-019-01307-0 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94794
in Journal of geodesy > vol 93 n°11 (November 2019)[article]Evaluation absolue de méthodes de localisation et de reconstruction panoramique et photogrammétrique d'un tunnel à partir d'un nuage de points de référence appliquée au tunnel-canal de Niderviller / Paul Chavant (2013)
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