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Comparative analysis of real-time precise point positioning zenith total delay estimates / F.A. Ahmed in GPS solutions, vol 20 n° 2 (April 2016)
[article]
Titre : Comparative analysis of real-time precise point positioning zenith total delay estimates Type de document : Article/Communication Auteurs : F.A. Ahmed, Auteur ; Pavel Vaclavovic, Auteur ; Felix Norman Teferle, Auteur ; Jan Douša, Auteur ; R.M. Bingley, Auteur ; Denis Laurichesse, Auteur Année de publication : 2016 Article en page(s) : pp 187 - 199 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse comparative
[Termes IGN] erreur moyenne
[Termes IGN] erreur systématique
[Termes IGN] modèle atmosphérique
[Termes IGN] positionnement ponctuel précis
[Termes IGN] retard troposphérique zénithal
[Termes IGN] temps réel
[Vedettes matières IGN] Traitement de données GNSSRésumé : (Auteur) The continuous evolution of global navigation satellite systems (GNSS) meteorology has led to an increased use of associated observations for operational modern low-latency numerical weather prediction (NWP) models, which assimilate GNSS-derived zenith total delay (ZTD) estimates. The development of NWP models with faster assimilation cycles, e.g., 1-h assimilation cycle in the rapid update cycle NWP model, has increased the interest of the meteorological community toward sub-hour ZTD estimates. The suitability of real-time ZTD estimates obtained from three different precise point positioning software packages has been assessed by comparing them with the state-of-the-art IGS final troposphere product as well as collocated radiosonde (RS) observations. The ZTD estimates obtained by BNC2.7 show a mean bias of 0.21 cm, and those obtained by the G-Nut/Tefnut software library show a mean bias of 1.09 cm to the IGS final troposphere product. In comparison with the RS-based ZTD, the BNC2.7 solutions show mean biases between 1 and 2 cm, whereas the G-Nut/Tefnut solutions show mean biases between 2 and 3 cm with the RS-based ZTD, and the ambiguity float and ambiguity fixed solutions obtained by PPP-Wizard have mean biases between 6 and 7 cm with the references. The large biases in the time series from PPP-Wizard are due to the fact that this software has been developed for kinematic applications and hence does not apply receiver antenna eccentricity and phase center offset (PCO) corrections on the observations. Application of the eccentricity and PCO corrections to the a priori coordinates has resulted in a 66 % reduction of bias in the PPP-Wizard solutions. The biases are found to be stable over the whole period of the comparison, which are criteria (rather than the magnitude of the bias) for the suitability of ZTD estimates for use in NWP nowcasting. A millimeter-level impact on the ZTD estimates has also been observed in relation to ambiguity resolution. As a result of a comparison with the established user requirements for NWP nowcasting, it was found that both the G-Nut/Tefnut solutions and one of the BNC2.7 solutions meet the threshold requirements, whereas one of the BNC2.7 solution and both the PPP-Wizard solutions currently exceed this threshold. Numéro de notice : A2016-611 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-014-0427-z En ligne : http://dx.doi.org/10.1007/s10291-014-0427-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81810
in GPS solutions > vol 20 n° 2 (April 2016) . - pp 187 - 199[article]Arta geophysical observatory (Republic of Djibouti) ITRF local tie survey, version 1 / Jean-Claude Poyard (2016)
Titre : Arta geophysical observatory (Republic of Djibouti) ITRF local tie survey, version 1 Type de document : Rapport Auteurs : Jean-Claude Poyard, Auteur Mention d'édition : Version 1 Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN (2012-) Année de publication : 2016 Collection : Publications techniques en géodésie Sous-collection : Rapports techniques num. 28549 Importance : 48 p. Format : 21 x 30 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] co-positionnement
[Termes IGN] Djibouti
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] point de liaison (géodésie)
[Termes IGN] rattachement de station
[Termes IGN] Regina
[Termes IGN] station DORIS
[Termes IGN] station GNSS
[Termes IGN] station permanente
[Termes IGN] temps réelMots-clés libres : Observatoire d'Arta CNES Résumé : (auteur) Dans le cadre des activités REGINA assurées par l'IGN, une mission d'installation d'une station GNSS temps réel à l'Observatoire d'Arta est planifiée en décembre 2013. Ce site étant déjà équipé d'une station DORIS donne lieu à un rattachement de précision. Le rapport présente le déroulement du rattachement et les résultats obtenus. Note de contenu : 1. Co-location site description
2. Local tie survey description
3. Computation
4. Results
5. AppendicesNuméro de notice : 19737 Affiliation des auteurs : IGN (2012-2019) Thématique : POSITIONNEMENT Nature : Rapport de mission Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84077 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 19737-01 7D Livre SGM K001 Exclu du prêt Documents numériques
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Arta geophysical observatory (Republic of Djibouti) Itrf local tie surveyAdobe Acrobat PDF Autonomous navigation in complex nonplanar environments based on laser ranging / Philipp Andreas Krüsi (2016)
Titre : Autonomous navigation in complex nonplanar environments based on laser ranging Type de document : Thèse/HDR Auteurs : Philipp Andreas Krüsi, Auteur Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Année de publication : 2016 Note générale : bibliographie
A thesis submitted to attain the degree of doctor of sciences of ETH ZurichLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] algorithme ICP
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] navigation autonome
[Termes IGN] robot mobile
[Termes IGN] semis de points
[Termes IGN] télémètre laser
[Termes IGN] télémétrie laser aéroporté
[Termes IGN] télémétrie laser terrestre
[Termes IGN] temps réel
[Termes IGN] vision par ordinateurRésumé : (auteur) This thesis addresses the problem of autonomous navigation with ground robots in complex environments, which may be characterized as nonplanar and nonstatic. The goal of the presented research is to enable reliable navigation over large distances in generic indoor and outdoor environments, independent of external localization sources such as a global positioning system (GPS). Focusing on these challenges, algorithms for all building blocks of autonomous navigation—localization, mapping, terrain assessment, motion planning, and motion control—are developed, implemented, integrated, and finally evaluated in extensive field experiments. Sensor-based perception of the environment is a basic requirement for localization and mapping. We propose to use a high-frequency three-dimensional (3D) laser scanner as the main exteroceptive sensor. The advantages of this technology lie in the high density and accuracy of the provided measurements, and their independence of lighting and weather conditions. We develop a highly scalable system for six-dimensional (6D) localization and 3D mapping based on iterative closest point (ICP) matching. A topological/metric map representation, where metric information is kept in spatially constrained local submaps representing vertices in a graph, allows to build consistent large-scale maps without requiring global optimization. Long-term application in dynamic and changing environments is enabled by integrating methods for identifying dynamic objects in the scene and for continuously updating existing submaps. Planning feasible and safe motions for a robotic vehicle requires distinguishing obstacles from traversable terrain. We develop two different algorithms for terrain assessment. The first method is targeted at real-time obstacle detection in the vicinity of the robot. Assuming locally planar terrain, a grid-based obstacle map is built by analyzing the raw laser scans. The second approach is based on dense point cloud maps (which can be obtained from the ICP mapping system) and suitable for planar and nonplanar environments. The algorithm computes the geometry and the traversability of the terrain “on demand” at specific query locations, avoiding any artificial discretization or explicit surface reconstruction. The desired terrain characteristics are estimated based on statistics on the local distribution of map points. Given a specific navigation task, motion planning can be defined as the problem of reasoning about how to act based on the knowledge about the environment. This thesis addresses both local obstacle avoidance and global planning over large distances. Our approach to local planning consists of computing a set of candidate trajectories, which are shaped around nearby obstacles or along a given reference path, and enforced to satisfy the robot’s kinematic constraints. The optimal local trajectory is chosen by evaluating the motion alternatives in terms of guidance towards the goal and traversability of the underlying terrain. For global motion planning, we develop an algorithm embedding the proposed point-cloud-based terrain assessment method, which allows trajectories to be directly planned on 3D point cloud maps. The approach is designed to be suitable for generic nonplanar environments, including rough outdoor terrain, multi-level facilities, and more complex geometries. Piecewise continuous trajectories are computed in the full 6D space of robot poses, while strictly considering the vehicle’s kinematic and dynamic constraints. We apply sampling-based planning algorithms to generate an initial trajectory connecting the desired start and goal poses. Subsequently, the trajectory is locally optimized according to a generic cost function, which may include path length, path curvature, and roughness of the traversed terrain. While enforcing the hard constraints to remain satisfied (terrain contact, traversability, kinodynamic feasibility), the trajectory is iteratively deformed until a local minimum of the cost function is reached. We develop two complete systems for autonomous navigation, integrating these approaches. Combining the ICP-based localization and mapping framework with local obstacle detection and local motion planning, we implement a framework for autonomous route following, commonly referred to as teach and repeat (T&R). After a manually controlled teach run, where a graph of local submaps is built, the robot is able to automatically repeat the learned route, using the recorded maps for localization. Unlike classical T&R systems, our framework is suitable for application in dynamic environments, where the integrated obstacle avoidance scheme allows to detect and circumnavigate obstacles appearing on the reference path. In addition to the T&R approach, we present a second navigation system, integrating the point-cloud-based terrain assessment and global planning algorithms with ICP-based localization and mapping. Given a graph of point cloud maps—typically recorded in a manually controlled survey run—the framework enables navigation within the mapped area without being restricted to known routes. Motion control is implemented by a trajectory tracking controller with integrated real-time collision checking. Together with continuous map updates and frequent replanning of the global trajectory, these techniques enable autonomous navigation in nonplanar, nonstatic environments. Finally, we describe the characteristics of the mobile robot ARTOR, which was set up for the purpose of testing and evaluating the developed algorithms under realistic conditions. ARTOR consists of a six-wheeled, electrically powered base vehicle equipped with sensors, computers, and communication gear. The proposed autonomous navigation algorithms were integrated on the robot and tested in extensive field experiments, demonstrating reliable, GPS-independent navigation over large distances and under greatly varying environmental conditions, in unstructured off-road terrain, multi-level environments, and dynamic urban areas. Numéro de notice : 17367 Affiliation des auteurs : non IGN Thématique : IMAGERIE/INFORMATIQUE Nature : Thèse étrangère Note de thèse : PhD thesis : Sciences : ETH Zurich : 2016 En ligne : http://dx.doi.org/10.3929/ethz-a-010656081 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84243 GNSS Satellite-Based Augmentation Systems : A potential new time keeping system for future generations / Carlo Cornacchini in Inside GNSS, vol 11 n° 1 (January - February 2016)
[article]
Titre : GNSS Satellite-Based Augmentation Systems : A potential new time keeping system for future generations Type de document : Article/Communication Auteurs : Carlo Cornacchini, Auteur ; Daniele Gianfelici, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 54 - 63 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] MTSAT
[Termes IGN] système d'extension
[Termes IGN] système de chronométrage
[Termes IGN] temps réelRésumé : (éditeur) This article describes development and testing of a novel time-keeping system for future architectures of satellite-based augmentation systems. It describes an operational test bed designed to support comparison tests and evaluation of the time-keeping system in light of existing SBAS programs and their requirements. In particular it will address the system design and performance validation of a new time-keeping system for a satellite-based augmentation system (SBAS) and the real-time test bed with which it was evaluated. This time-keeping system could provide increased time-synchronization performance for future upgrades of both the onboard and ground segments of SBAS systems. Numéro de notice : A2016-262 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : http://www.insidegnss.com/node/4790 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80795
in Inside GNSS > vol 11 n° 1 (January - February 2016) . - pp 54 - 63[article]Indoor navigation of mobile robots based on visual memory and image-based visual servoing / Suman Raj Bista (2016)
Titre : Indoor navigation of mobile robots based on visual memory and image-based visual servoing Type de document : Thèse/HDR Auteurs : Suman Raj Bista, Auteur ; François Chaumette, Auteur ; Paolo Robuffo Giordano, Auteur Editeur : Rennes : Université de Rennes 1 Année de publication : 2016 Autre Editeur : Rennes : Université Bretagne Loire Importance : 168 p. Format : 21 x 30 cm Note générale : bibliographie
Thesis for the degree of PhD in Signal Processing and Communication, Rennes 1 University, Doctoral School Matisse, Rennes, 2016Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] base de données d'images
[Termes IGN] GNSS assisté pour la navigation
[Termes IGN] image numérique
[Termes IGN] instrument embarqué
[Termes IGN] navigation
[Termes IGN] positionnement en intérieur
[Termes IGN] robot mobile
[Termes IGN] robotique
[Termes IGN] segment de droite
[Termes IGN] temps réel
[Termes IGN] traitement d'image
[Termes IGN] vision par ordinateurIndex. décimale : THESE Thèses et HDR Résumé : (auteur) Cette thèse présente une méthode de navigation par asservissement visuel à l'aide d'une mémoire d'images. Le processus de navigation est issu d'informations d'images 2D sans utiliser aucune connaissance 3D. L'environnement est représenté par un ensemble d'images de référence avec chevauchements, qui sont automatiquement sélectionnés au cours d'une phase d'apprentissage préalable. Ces images de référence définissent le chemin à suivre au cours de la navigation. La commutation des images de référence au cours de la navigation est faite en comparant l'image acquise avec les images de référence à proximité. Basé sur les images actuelles et deux images de référence suivantes, la vitesse de rotation d'un robot mobile est calculée en vertu d'une loi du commandé par asservissement visuel basé image. Tout d'abord, nous avons utilisé l'image entière comme caractéristique, où l'information mutuelle entre les images de référence et la vue actuelle est exploitée. Ensuite, nous avons utilisé des segments de droite pour la navigation en intérieur, où nous avons montré que ces segments sont de meilleurs caractéristiques en environnement intérieur structuré. Enfin, nous avons combiné les segments de droite avec des points pour augmenter l'application de la méthode à une large gamme de scénarios d'intérieur pour des mouvements sans heurt. La navigation en temps réel avec un robot mobile équipé d'une caméra perspective embarquée a été réalisée. Les résultats obtenus confirment la viabilité de notre approche et vérifient qu'une cartographie et une localisation précise ne sont pas nécessaire pour une navigation intérieure utile. Note de contenu : Introduction
1 - Preliminaries and state of art
2 - Our contribution
3 - Summary
ConclusionNuméro de notice : 21580 Affiliation des auteurs : non IGN Thématique : IMAGERIE/INFORMATIQUE Nature : Thèse française Note de thèse : thèse de doctorat : Traitement du signal et communication : Rennes 1 : 2016 Organisme de stage : Lagadic Group (Inria Rennes) nature-HAL : Thèse DOI : sans En ligne : http://www.theses.fr/2016REN1S074 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90594 On the estimability of parameters in undifferenced, uncombined GNSS network and PPP-RTK user models by means of S-system theory / Dennis Odijk in Journal of geodesy, vol 90 n° 1 (January 2016)PermalinkProgressive streaming and massive rendering of 3D city models on web-based virtual globe / Quoc-Dinh Nguyen (2016)PermalinkReal-time depth-image-based rendering for viewpoint-variable display on mobile devices / Shuoran Yang (2016)PermalinkRealtime projective multi-texturing of pointclouds and meshes for a realistic street-view web navigation / Alexandre Devaux (2016)PermalinkReal-time atmospheric correction of AVIRIS-NG imagery / Brian D. Bue in IEEE Transactions on geoscience and remote sensing, vol 53 n° 12 (December 2015)PermalinkVisualisez l'essentiel en temps réel ! Pas à pas, créez un tableau de bord avec Operations Dashboard for ArcGIS / Xavier Fodor in SIGmag, n° 7 (décembre 2015)PermalinkAn analytical study of PPP-RTK corrections: precision, correlation and user-impact / Amir Khodabandeh in Journal of geodesy, vol 89 n° 11 (november 2015)PermalinkCar navigation – computing routes that avoid complicated crossings / Jukka Mathias Krisp in International journal of geographical information science IJGIS, vol 29 n° 11 (November 2015)PermalinkParticle filter-based estimation of inter-frequency phase bias for real-time GLONASS integer ambiguity resolution / Yumiao Tian in Journal of geodesy, vol 89 n° 11 (november 2015)PermalinkImpacts of real-time satellite clock errors on GPS precise point positioning-based troposphere zenith delay estimation / Junbo Shi in Journal of geodesy, vol 89 n° 8 (August 2015)Permalink