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Antenna phase center correction differences from robot and chamber calibrations: the case study LEIAR25 / Grzegorz Krzan in GPS solutions, vol 24 n° 2 (April 2020)  

Public [article]  inGPS solutions > vol 24 n° 2 (April 2020) Titre : Antenna phase center correction differences from robot and chamber calibrations: the case study LEIAR25 Type de document : Article/Communication Auteurs : Grzegorz Krzan, Auteur ; Karol Dawidowicz, Auteur ; Pawel Wielgosz, Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] antenne GLONASS [Termes descripteurs IGN] antenne GNSS [Termes descripteurs IGN] antenne GPS [Termes descripteurs IGN] centre de phase [Termes descripteurs IGN] chambre anéchoïque [Termes descripteurs IGN] correction du signal [Termes descripteurs IGN] étalonnage d'instrument [Termes descripteurs IGN] instrumentation Leica [Termes descripteurs IGN] positionnement par GNSS [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] robot [Termes descripteurs IGN] série temporelle [Termes descripteurs IGN] signal GNSS Résumé : (auteur) In recent years, the Global Navigation Satellite Systems (GNSS) have been intensively modernized, resulting in the introduction of new carrier frequencies for GPS and GLONASS and the development of new satellite systems such as Galileo and BeiDou (BDS). For this reason, the absolute field antenna calibrations performed so far for the two legacy carrier frequencies, the GPS and GLONASS, seem to be insufficient. Hence, all antennas will require a re-calibration of their phase center variations for the new signals to ensure the highest measurement accuracy. Currently, two absolute calibration methods are used to calibrate GNSS antennas: field calibration using a robot and calibration in an anechoic chamber. Unfortunately, differences in these methodologies also result in a disparity in the obtained antenna phase center corrections (PCC). Therefore, we analyze the differences between individual PCC obtained with these two methods, specifically for the Leica AR-25 antenna model (LEIAR25). In addition, the influence of PCC differences on the GNSS-derived position time series for 19 EUREF Permanent GNSS Network (EPN) stations was also assessed. The results show that the calibration method has a noticeable impact on PCC models. PCC differences determined for the ionosphere-free combination may reach up over 20 mm and can be transferred to the position domain. Further tests concerning the positioning accuracy showed that for horizontal coordinates differences between solutions were mostly below 1 mm, exceeding 2 mm only at two stations for the GLONASS solution. However, the height component differences exceeded 5 mm for four, six and six stations out of 19 for the GPS, GLONASS and Galileo solutions, respectively. These differences are strongly dependent on large L2 calibration differences. Numéro de notice : A2020-081 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-020-0957-5 date de publication en ligne : 11/02/2020 En ligne : https://doi.org/10.1007/s10291-020-0957-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94650 [article]

Absolute field calibration for multi-GNSS receiver antennas at ETH Zurich / Daniel Willi in GPS solutions, vol 24 n° 1 (January 2020)  

Public [article]  inGPS solutions > vol 24 n° 1 (January 2020) Titre : Absolute field calibration for multi-GNSS receiver antennas at ETH Zurich Type de document : Article/Communication Auteurs : Daniel Willi, Auteur ; Simon Lutz, Auteur ; Elmar Brockmann, Auteur ; Markus Rothacher, Auteur Année de publication : 2020 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] antenne Galileo [Termes descripteurs IGN] antenne GNSS [Termes descripteurs IGN] antenne GPS [Termes descripteurs IGN] centre de phase [Termes descripteurs IGN] données Galileo [Termes descripteurs IGN] données GPS [Termes descripteurs IGN] données multicapteurs [Termes descripteurs IGN] étalonnage au sol [Termes descripteurs IGN] étalonnage d'instrument [Termes descripteurs IGN] étalonnage des données [Termes descripteurs IGN] international GPS service for geodynamics [Termes descripteurs IGN] mesurage de phase [Termes descripteurs IGN] récepteur GNSS [Termes descripteurs IGN] robot [Termes descripteurs IGN] signal GNSS [Termes descripteurs IGN] Zurich (Suisse) Résumé : (Auteur) ETH Zurich developed an absolute GNSS antenna calibration system based on measurements taken in the field. An industrial robot is used to rotate and tilt the antenna to be calibrated. This procedure ensures good coverage of the antenna hemisphere and reduces systematic errors. The calibration system at ETH Zurich is validated by a direct comparison of the obtained calibrations with calibrations from the anechoic chamber method (University of Bonn) and from another absolute field calibration method (Geo++® GmbH). Calibrations by ETH Zurich agree on the sub-millimeter level with both reference calibrations. A second validation was conducted using real measurements on short baselines. Data were acquired on four stations in direct vicinity and processed using different phase center correction models. The experiment shows that individual corrections of ETH Zurich reduce the residuals in the coordinate domain when compared to type-mean calibrations of the International GNSS Service (IGS). However, residual biases between GPS and Galileo coordinates remain. These biases are efficiently reduced when using the new type-mean calibrations from the IGS that include calibration values for all GNSS, including Galileo. The ETH Zurich calibration system is proven to deliver meaningful calibrations that agree with other calibrations on the millimeter level in the azimuth and elevation domain. The field validation shows evidence that the consistency of the Galileo and GPS calibration should be further enhanced by performing a combined GPS and Galileo analysis, which is not yet implemented. Numéro de notice : A2020-020 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-019-0941-0 date de publication en ligne : 19/12/2019 En ligne : https://doi.org/10.1007/s10291-019-0941-0 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94460 [article]

Assessment of next-best-view algorithms performance with various 3D scanners and manipulator / M. Karaszewski in ISPRS Journal of photogrammetry and remote sensing, vol 119 (September 2016)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 119 (September 2016) . - pp 320-333 Titre : Assessment of next-best-view algorithms performance with various 3D scanners and manipulator Type de document : Article/Communication Auteurs : M. Karaszewski, Auteur ; M. Adamczyk, Auteur ; R. Sitnik, Auteur Année de publication : 2016 Article en page(s) : pp 320-333 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes descripteurs IGN] analyse comparative [Termes descripteurs IGN] capteur imageur [Termes descripteurs IGN] évaluation des paramètres [Termes descripteurs IGN] orientation du capteur [Termes descripteurs IGN] robot [Termes descripteurs IGN] système de numérisation mobile [Termes descripteurs IGN] test de performance Résumé : (Auteur) The problem of calculating three dimensional (3D) sensor position (and orientation) during the digitization of real-world objects (called next best view planning or NBV) has been an active topic of research for over 20 years. While many solutions have been developed, it is hard to compare their quality based only on the exemplary results presented in papers. We implemented 13 of the most popular NBV algorithms and evaluated their performance by digitizing five objects of various properties, using three measurement heads with different working volumes mounted on a 6-axis robot with a rotating table for placing objects. The results obtained for the 13 algorithms were then compared based on four criteria: the number of directional measurements, digitization time, total positioning distance, and surface coverage required to digitize test objects with available measurement heads. Numéro de notice : A2016-786 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern En ligne : http://dx.doi.org/10.1016/j.isprsjprs.2016.06.015 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82501 [article]

Acquisition et reconstruction de données 3D denses sous-marines en eau peu profonde par des robots d'exploration / Loïca Avanthey (2016)  

Public Titre : Acquisition et reconstruction de données 3D denses sous-marines en eau peu profonde par des robots d'exploration Type de document : Thèse/HDR Auteurs : Loïca Avanthey, Auteur ; Michel Roux, Directeur de thèse ; Laurent Beaudoin, Directeur de thèse Editeur : Paris [France] : Télécom ParisTech Année de publication : 2016 Importance : 262 p. Format : 21 x 30 cm Note générale : bibliographie Thèse pour obtenir le grade de docteur délivré par Télécom Paris Tech, spécialité Signal et Images Langues : Français (fre) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes descripteurs IGN] acquisition de données [Termes descripteurs IGN] appariement de points [Termes descripteurs IGN] capteur optique [Termes descripteurs IGN] carte bathymétrique [Termes descripteurs IGN] couple stéréoscopique [Termes descripteurs IGN] données de terrain [Termes descripteurs IGN] données localisées 3D [Termes descripteurs IGN] étalonnage de capteur (imagerie) [Termes descripteurs IGN] fond marin [Termes descripteurs IGN] réalité de terrain [Termes descripteurs IGN] recalage de données localisées [Termes descripteurs IGN] reconstruction 3D [Termes descripteurs IGN] relief sous-marin [Termes descripteurs IGN] robot [Termes descripteurs IGN] scène sous-marine [Termes descripteurs IGN] semis de points Index. décimale : THESE Thèses et HDR Résumé : (auteur) Notre planète est pour l’essentiel recouverte par les mers et les océans, or notre connaissance des fonds marins est très inférieure à celle que nous possédons sur les terres émergées. Dans ce mémoire, nous cherchons à concevoir un système dédié à la cartographie thématique à grande échelle pour obtenir à la demande un nuage de points dense représentatif d’une scène sous-marine ou subaquatique par reconstruction tridimensionnelle. Le caractère complexe de ce type de système nous amène à privilégier une approche délibérément transversale. Nous nous intéresserons en particulier aux problématiques posées par l’étude à l’échelle des individus de petites zones en eau peu profonde. Les premières concernent l’acquisition in situ efficace de couples stéréoscopiques avec une logistique adaptée à la taille des zones observées : nous proposons pour cela un microsystème agile, peu coûteux et suffisamment automatisé pour fournir des données reproductibles et comparables. Les secondes portent sur l’extraction fiable de l’information tridimensionnelle à partir des données acquises : nous exposons les algorithmes que nous avons élaborés pour prendre en compte les caractéristiques particulières du milieu aquatique (dynamisme, propagation difficile des ondes électromagnétiques, etc.). Nous abordons donc en détail dans ce mémoire les problèmes d’appariement dense, d’étalonnage, d’acquisition in situ, de recalage et de redondance des données rencontrés dans le milieu sous-marin. Note de contenu : Introduction 1 - Contexte 2 - Nuages de points sous-marins 3 - Mise en oeuvre et analyse 4 - Conclusion et perspectives Numéro de notice : 21585 Thématique : IMAGERIE Nature : Thèse française Note de thèse : Thèse : Signal et Image : Télécom Paris Tech : 2016 En ligne : http://www.theses.fr/2016ENST0055 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90609

Ableitung von Bewegungsstrategien zur automatisierten, vollständigen Vermessung von Innerraumszenen auf autonom navigierender Plattform / A. Fietz (2012) 

Public Titre : Ableitung von Bewegungsstrategien zur automatisierten, vollständigen Vermessung von Innerraumszenen auf autonom navigierender Plattform Titre original : [Détournement (ou dérivation) de stratégies de mouvement pour la mesure complète et automatisée de scènes spatiales intérieures sur la plate-forme de navigation autonome] Type de document : Thèse/HDR Auteurs : A. Fietz, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2012 Collection : DGK - C Sous-collection : Dissertationen num. 685 Importance : 164 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5097-6 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes descripteurs IGN] bloc photo [Termes descripteurs IGN] chambre de prise de vue numérique [Termes descripteurs IGN] compensation par faisceaux [Termes descripteurs IGN] données lidar [Termes descripteurs IGN] données localisées 2D [Termes descripteurs IGN] données localisées 3D [Termes descripteurs IGN] lasergrammétrie [Termes descripteurs IGN] photogrammétrie terrestre [Termes descripteurs IGN] plateforme [Termes descripteurs IGN] positionnement en intérieur [Termes descripteurs IGN] reconstruction 3D [Termes descripteurs IGN] robot [Termes descripteurs IGN] segment de droite [Termes descripteurs IGN] système de numérisation mobile [Termes descripteurs IGN] tachéomètre électronique [Termes descripteurs IGN] variance Résumé : (Auteur) A fundamental task of an autonomous mobile robot is the ability of self-localization in its environment respectively in a map of it, available to the robot. Many applications require a localization that is as precise as possible. Thereby, a decisive factor is the accuracy but also the completeness of the map. The generated map can usually be seen as a necessary side-product. When considered from a surveying point of view, it is brought more into focus. The question is to what extent the spatial robot data can fulfill certain mapping requirements in terms of accuracy and completeness in a detailed enough manner to be useful to human users. Precise models of indoor environments are very useful in both public and private sectors. But since their procurement involves a great deal of effort, an automatical generation of indoor models is desirable. The following thesis should make a contribution to this and tries to compose the techniques that are necessary to deliver interior models at the push of a button. Therefore, a mobile measuring system was designed, that is able to carry out complete and precise measurements of indoor environments. The system was build up in two stages. A mobile platform is equipped with a low-cost laser scanner in the basic stage. This build-up allows a precise exploration of indoor scenes in 2D. In an expansion stage the installation of a digital camera leads to an additional 3D reconstruction based on photogrammetric techniques. The accuracy and quality of robotic mapping is primarily dependent on the sensors that are used. The software process to register the collected data in a common coordinate frame and to create a holistic map of the environment has an additional influence. In the field of scanning systems scan matching techniques or probabilistic filter approaches are used. In the case of 3D surveying, a photogrammetric reconstruction can be done by an estimation of feature points, which are extracted from a photo block, within a bundle adjustment process. Results can be optimized, if requirements and restrictions of these techniques are regarded in the data acquisition process, when the robot proceeds the exploration. A crucial aspect is the spatial sensor placement at a certain point of time in this process. In the field of robotics, sensor placement is controlled by positioning strategies, which normally are of overriding importance to all other processes. The majority of known positioning strategies have the primary aim to optimize the efficiency of the exploration, so that every measurement provides as much new spatial information as possible. Requirements of the data registration technique are neglected in contrast. This thesis presents positioning strategies for scanning 2D measurements as well as photogrammetric 3D measurements, which try to maximize the accuracy of the collected spatial data. A scanning 2D measuring system, which is able to explore previously unknown indoor environments and generate precise floor plans is presented in the first part of this thesis. The system iteratively visits measurement poses defined by a positioning strategy. 2D point clouds, collected at various positions, are transformed into a common coordinate system by the use of a scan matching technique. The latter takes advantage of the characteristic manifestation of office environments and extracts planar segments from the measured point clouds. Minimizing the sum of perpendicular distances to these segments, points of a new scan are transformed into the existing coordinate system with high accuracy. Precision and robustness are improved through iterative parameter refinement. The measuring system uses a positioning strategy, which is based on the global assumption that the environment can be described as a collection of line segments. Since segment ends indicate data gaps, exploration is pushed until their observation is complete. All accessible measuring positions, represented in an occupancy grid, are evaluated in terms of their explorative benefit by the strategy using a cost function. Exploration is stopped as soon as every section is observed with a desired resolution. The second part of this work presents a positioning strategy to enable the recording of photo blocks that are suitable for a photogrammetric reconstruction. In the run-up of data acquisition possible pose configurations are determined using accuracy estimation. The assumption of plain environments allows a limitation to a 2D search problem regarding the choice of possible camera poses, whereby the combinatorial variety is reduced. Initial information of pose estimation provides a 2D map, generated by the system structure that was presented in the first part of this work. For predefined sections of the environment, pseudo-random pose constellations are derived iteratively from the map and compared with each other using a cost function. The cost function helps to predict the variances resulting from a bundle adjustment. Therefore the functional model of the bundle adjustment has to be projected on the R2 in a way that a geodetic network consisting of direction measurements remains. The size and the shape of the resulting error ellipses allow conclusions and a comparative consideration regarding the quality of camera pose candidates. An essential part of the work is the empirical analysis of the systems, to evaluate their performance and the quality of the resulting spatial data. Various experiments in real indoor environments show that developed measurement methods can be applied in practice. In different sets of experiments initial conditions are varied to find out their influence on the measurement process or the result. In order to achieve reliable results, reference models of the experimental environments were created by the use of a total station. In the case of scanner measurements, experiments show that the developed system is able to explore and measure also complex interiors. An examination of the point clouds show that the achieved accuracy comes up with surveying demands. On this issue, the presented technique outplays conventional measuring equipment. However, additional modeling shows that mainly fine structures of the environment are displayed wrongly or are even lost completely. Also the 3D measuring strategy is demonstrably superior to existing techniques. The purely passive technique leads to sparse point clouds, not dense enough to derive detailed environment models with the corresponding software. Numéro de notice : 14621 Thématique : IMAGERIE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62672

Documents numériques

en open access 14621_dgk-c-685_fietz.pdf Adobe Acrobat PDF

It's a robot life: using GPS and pseudolites for humanoid robot positioning / S. Sugano in GPS world, vol 18 n° 9 (September 2007)

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Photogrammétrie et archéologie sous-marine profonde : le cas de l'épave étrusque grand Ribaud F [1ère partie] / P. Drap in XYZ, n° 103 (juin - août 2005)

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Robots behind the wheel: GPS/INS-vehicle assessment / B. Watts in GPS world, vol 14 n° 7 (July 2003)

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Robot location using single views of rectangular shapes / L. Royal in Photogrammetric Engineering & Remote Sensing, PERS, vol 56 n° 2 (february 1990)

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MICAD 85, Actes de la 4ème Conférence Européenne sur la CFAO et l'Infographie, 1. Volume 1 / Micad (1985)

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MICAD 85, Actes de la 4ème Conférence Européenne sur la CFAO et l'Infographie, 2. Volume 2 / Micad (1985)

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