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Auteur Volker Schwieger |
Documents disponibles écrits par cet auteur (5)
Ajouter le résultat dans votre panier Affiner la recherche Interroger des sources externesReducing multipath effect of low-cost GNSS receivers for monitoring by considering temporal correlations / Li Zhang in Journal of applied geodesy, vol 14 n° 2 (April 2020)
Titre : Reducing multipath effect of low-cost GNSS receivers for monitoring by considering temporal correlations Type de document : Article/Communication Auteurs : Li Zhang, Auteur ; Volker Schwieger, Auteur Année de publication : 2020 Article en page(s) : pp 167 – 175 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] atténuation du signal
[Termes IGN] corrélation temporelle
[Termes IGN] coût
[Termes IGN] itération
[Termes IGN] ligne de base
[Termes IGN] oscillation
[Termes IGN] phase
[Termes IGN] plan de masse
[Termes IGN] qualité des données
[Termes IGN] récepteur GNSS
[Termes IGN] récepteur monofréquence
[Termes IGN] réflecteur
[Termes IGN] source d'erreur
[Termes IGN] trajet multipleRésumé : (auteur) The investigations on low-cost single frequency GNSS receivers at the Institute of Engineering Geodesy (IIGS) show that u-blox GNSS receivers combined with low-cost antennas and self-constructed L1-optimized choke rings can reach an accuracy which almost meets the requirements of geodetic applications (see Zhang and Schwieger [25]). However, the quality (accuracy and reliability) of low-cost GNSS receiver data should still be improved, particularly in environments with obstructions. The multipath effects are a major error source for the short baselines. The ground plate or the choke ring ground plane can reduce the multipath signals from the horizontal reflector (e. g. ground). However, the shieldings cannot reduce the multipath signals from the vertical reflectors (e. g. walls). Because multipath effects are spatially and temporally correlated, an algorithm is developed for reducing the multipath effect by considering the spatial correlations of the adjoined stations (see Zhang and Schwieger [24]). In this paper, an algorithm based on the temporal correlations will be introduced. The developed algorithm is based on the periodic behavior of the estimated coordinates and not on carrier phase raw data, which is easy to use. Because, for the users, coordinates are more accessible than the raw data. The multipath effect can cause periodic oscillations but the periods change over time. Besides this, the multipath effect’s influence on the coordinates is a mixture of different multipath signals from different satellites and different reflectors. These two properties will be used to reduce the multipath effect. The algorithm runs in two steps and iteratively. Test measurements were carried out in a multipath intensive environment; the accuracies of the measurements are improved by about 50 % and the results can be delivered in near-real-time (in ca. 30 minutes), therefore the algorithm is suitable for structural health monitoring applications. Numéro de notice : A2020-217 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2019-0059 Date de publication en ligne : 27/03/2020 En ligne : https://doi.org/10.1515/jag-2019-0059 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94910
in Journal of applied geodesy > vol 14 n° 2 (April 2020) . - pp 167 – 175[article]
Titre : Experimental results of multipath behavior for GPS L1-L2 and Galileo E1-E5b in static and kinematic scenarios Type de document : Article/Communication Auteurs : Alexandra Avram, Auteur ; Volker Schwieger, Auteur Année de publication : 2019 Article en page(s) : pp 279 - 289 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] navigation autonome
[Termes IGN] positionnement cinématique
[Termes IGN] positionnement par Galileo
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement statique
[Termes IGN] trajet multipleRésumé : (auteur) Current trends like Autonomous Driving (AD) increase the need for a precise, reliable, and continuous position at high velocities. In both natural and man-made environments, Global Navigation Satellite System (GNSS) signals suffer challenges such as multipath, attenuation, or loss-of-lock. As Highway Assist and Highway Pilot are AD next steps, multipath knowledge is necessary for this typical user-case and kinematic situations. This paper presents a multipath performance analysis for GPS and Galileo satellites in static, slow, and high kinematic scenarios. The data is provided from car test-drives in both controlled and unrestricted, near-natural environments. The Code-Minus-Carrier (CMC) and cycle-slip implementations are validated with measurement data from consecutive days. Multipath statistical models based on satellite elevation are evaluated for the three investigated scenarios. Static models derived from the car setup measurements for GPS L1, L2 and Galileo E1 and E5b show a good agreement with a state-of-the-art model as well as the enhanced Galileo signals performance. Slow kinematic multipath results in a controlled environment showed an improvement for both navigation systems compared to the static measurements at the same place. This result is confirmed by static and slow kinematic multipath simulations with the same GNSS receiver. Post-processing analysis on highway measurements revealed a bigger multipath bias, compared to the open-sky static and slow kinematic measurement campaigns. Although less critical as urban or rural, this indicates the presence of multipath in this kind of environment as well. The impact of different parameters, including receiver architecture and Signal-to-noise ratio (SNR) are analyzed and discussed. Differential position (DGNSS) based on code is computed for each epoch and compared against GNSS/INS integrated position for all three measurement campaigns. The most significant 3D absolute error occurs where the greatest multipath envelope is found. Numéro de notice : A2019-540 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2019-0010 Date de publication en ligne : 31/07/2019 En ligne : https://doi.org/10.1515/jag-2019-0010 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94179
in Journal of applied geodesy > Vol 13 n° 4 (October 2019) . - pp 279 - 289[article]
Titre : Improving the quality of low-cost GPS receiver data for monitoring using spatial correlations Type de document : Article/Communication Auteurs : Li Zhang, Auteur ; Volker Schwieger, Auteur Année de publication : 2016 Article en page(s) : pp 119 - 129 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] correction du trajet multiple
[Termes IGN] corrélation automatique de points homologues
[Termes IGN] coût
[Termes IGN] récepteur GPS
[Termes IGN] récepteur monofréquence
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) The investigations on low-cost single frequency GPS receivers at the Institute of Engineering Geodesy (IIGS) show that u-blox LEA-6T GPS receivers combined with Trimble Bullet III GPS antennas containing self-constructed L1-optimized choke rings can already obtain an accuracy in the range of millimeters which meets the requirements of geodetic precise monitoring applications (see [27]). However, the quality (accuracy and reliability) of low-cost GPS receiver data, particularly in shadowing environment, should still be improved, since the multipath effects are the major error for the short baselines.
For this purpose, several adjoined stations with low-cost GPS receivers and antennas were set up next to the metal wall on the roof of the IIGS building and measured statically for several days. The time series of three-dimensional coordinates of the GPS receivers were analyzed. Spatial correlations between the adjoined stations, possibly caused by multipath effect, will be taken into account. The coordinates of one station can be corrected using the spatial correlations of the adjoined stations, so that the quality of the GPS measurements is improved.
The developed algorithms are based on the coordinates and the results will be delivered in near-real-time (in about 30 minutes), so that they are suitable for structural health monitoring applications.Numéro de notice : A2016-559 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2015-0022 En ligne : http://dx.doi.org/10.1515/jag-2015-0022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81738
in Journal of applied geodesy > vol 10 n° 2 (June 2016) . - pp 119 - 129[article]
Titre : The contribution of the surveying profession to disaster risk management Type de document : Article/Communication Auteurs : Volker Schwieger, Auteur ; O. Altan, Auteur ; H. Müller, Auteur ; H. Friesecke, Auteur ; T. Kötter, Auteur Année de publication : 2006 Article en page(s) : pp 245 - 267 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Information géographique
[Termes IGN] développement durable
[Termes IGN] géomètre
[Termes IGN] photogrammétrie spatiale
[Termes IGN] plan d'exposition aux risques
[Termes IGN] positionnement par GNSS
[Termes IGN] prévention des risques
[Termes IGN] risque naturel
[Termes IGN] risque technologique
[Termes IGN] séisme
[Termes IGN] système d'information géographiqueRésumé : (Auteur) In the past decades, the damage due to natural and man-made disasters increased worldwide in amount and magnitude. According to the Munich Re Group, the year 2005 set a new record with overall losses exceeding US$ 210 billion and more than one hundred thousand people killed as a result of natural catastrophes. Hurricane Katrina which caused the New Orleans flood in the United States was the most expensive natural catastrophe loss in history. Rapid population growth, global climate changes and the over-exploitation of natural resources are mainly responsible for these disasters. To break and, if possible, reverse this negative trend, International Federation of Surveyors (FIG) implemented a working group in 2003 to identify the current and future needs for research and action in the field of disaster risk management. After three years of research in the form of expert meetings, as well as papers and posters presented at five FIG conferences, the International Federation of Surveyors published this report, which presents those application-oriented concepts, methods, and instruments deemed to enable effective disaster risk management. The report shows clearly that disaster risk reduction could (and should!) be an essential field of application for the surveyor/geomatics/engineer/geodesist/land manager professional. The wide scope of surveyors’ abilities —such as, land management, geodetic engineering, geo-informatics, satellite technology, and remote sensing— can make an important contribution to improving, simplifying, and shortening the disaster management process. In addition to these engineering skills and knowledge, good governance and capacity development are central components of implementing sustainable and effective disaster risk management. FIG intends to contribute effectively to the success of mitigating natural and man-made disasters. I wish to thank the members of the FIG Working Group 8.4, the sister organizations of FIG, and other organizations who have contributed to this publication for their constructive and helpful work. My special thanks go to Svein Tveitdal, Director of UNEP/DEC/DEPI, for supporting the FIG work and for acting jointly with FIG to make sustainable development for future generations a reality. Copyright SaLIS Numéro de notice : A2006-606 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28329
in Surveying and land information science > vol 66 n° 4 (01/12/2006) . - pp 245 - 267[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 121-06041 RAB Revue Centre de documentation En réserve L003 Disponible Nicht-lineare Sensitivitätsanalyse gezeigt an Beispielen zu bewegten Objekten / Volker Schwieger (2005)
Titre : Nicht-lineare Sensitivitätsanalyse gezeigt an Beispielen zu bewegten Objekten Titre original : [Analyse de sensibilité non linéaire montrée avec des exemples d'objets mobiles] Type de document : Thèse/HDR Auteurs : Volker Schwieger, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2005 Collection : DGK - C Sous-collection : Dissertationen num. 581 Importance : 100 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5020-4 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse de sensibilité
[Termes IGN] coordonnées GPS
[Termes IGN] corrélation
[Termes IGN] filtre de Kalman
[Termes IGN] intégrale de Fourier
[Termes IGN] modèle stochastique
[Termes IGN] objet mobile
[Termes IGN] régression non linéaireIndex. décimale : 30.60 Géodésie spatiale Résumé : (Auteur) One important task of engineering geodesy is the evaluation of measurements by suitable models and the validation and optimisation of these models. Currently more complex and non-linear models are used in engineering geodesy. Therefore a model independent validation method, the variance-based sensitivity analysis method is introduced and applied to moving objects. An overview about different sensitivity analysis methods is given. Thereby the focus is on sample-based methods, that base on Monte-Carlo simulation. First of all the regression analysis and the rank regression analysis are described. These methods are used for the sensitivity analysis of linear respectively non-linear but monotone models. Subsequently the importance of a sensitivity analysis methods that are independent of model characteristics is shown. These are SOBOLs method, that uses multidimensional averaging to get quantitative results and the FOURIER Amplitude Sensitivity Test, that realises the same in the frequency domain. The presented methods are applied for two examples. Firstly the configuration for the height monitoring of a church is validated. Secondly the determination of a trajectory of motor vehicle using a circle model is controlled. For both applications adapted KALMAN filter algorithms are used. For the height monitoring problem a non-linear model behaviour can not be proved. Besides it can be shown that the variances of some height points have a decisive influence on the variances of the estimated movement parameters. For the second application, the analysis shows that the variances of the state parameters of the trajectory determination are effected decisively by the variances of the GPS coordinates. The model shows a non-linear as well as a non-additive behaviour. Numéro de notice : 13268 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54948 Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 13268-01 30.60 Livre Centre de documentation Géodésie Disponible 13268-02 30.60 Livre Centre de documentation Géodésie Disponible
