Descripteur
Documents disponibles dans cette catégorie (1225)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
Titre : Vehicle dynamic model based navigation for small UAVs Type de document : Thèse/HDR Auteurs : Mehran Khaghani, Auteur ; Jan Skaloud, Directeur de thèse Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2018 Autre Editeur : Lausanne : Ecole Polytechnique Fédérale de Lausanne EPFL Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 101 Importance : 138 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-47-5 Note générale : bibliography
Thèse de Doctorat, EPFL, Lausanne, 2018Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] analyse de sensibilité
[Termes IGN] centrale inertielle
[Termes IGN] démonstration de faisabilité
[Termes IGN] drone
[Termes IGN] filtre de Kalman
[Termes IGN] GPS-INS
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] modèle de simulation
[Termes IGN] modèle dynamique
[Termes IGN] navigation autonome
[Termes IGN] positionnement par GNSS
[Termes IGN] processus stochastique
[Termes IGN] ventIndex. décimale : 30.70 Navigation et positionnement Résumé : (auteur) The dominant navigation system for small civilian UAVs today is based on integration of inertial navigation system (INS) and global navigation satellite system (GNSS). This strategy works well to navigate the UAV, as long as proper reception of GNSS signal is maintained. However, when GNSS outage occurs, the INS-based navigation solution drifts very quickly, considering the limited quality of IMU(s) employed in INS for small UAVs. In beyond visual line of sight (BVLOS) flights, this poses the serious danger of losing the UAV and its eventual falling down. Limited payload capacity and cost for small UAVs, as well as the need for operating in different conditions, with limited visibility for example, make it challenging to find a solution to reach higher levels of navigation autonomy based on conventional approaches. This thesis aims to improve the accuracy of autonomous navigation for small UAVs by at least one order of magnitude. The proposed novel approach employs vehicle dynamic model (VDM) as process model within navigation system, and treats data from other sensors such as IMU, barometric altimeter, and GNSS receiver, whenever available, as observations within the system. Such improvement comes with extra effort required to determine the VDM parameters for any specific UAV. This work investigates the internal capability of the proposed system for estimating VDM parameters as part of the augmented state vector within an extended Kalman filter (EKF) as the estimator. This reduces the efforts required to setup such navigation system that is platform dependent. Multiple experimental flights using two custom made fixed-wing UAVs are presented together with Monte-Carlo simulations. The results reveal improvements of 1 to 2 orders of magnitude in navigation accuracy during GNSS outages of a few minutes' duration. Computational cost for the proposed VDM-based navigation does not exceed 3~times that of conventional INS-based systems, which establishes its applicability for online application. A global sensitivity analysis is presented, spotting the VDM parameters with higher influence on navigation performance. This provides insight for design of calibration procedures. The proposed VDM-based navigation system can be interesting for professional UAVs from at least two points of view. Firstly, it adds little to no extra hardware and cost to the UAV. Secondly and more importantly, it might be currently the only way to reach such significant improvement in navigation autonomy for small UAVs regardless of visibility conditions and electromagnetic signals reception. Possibly, such environmental condition independence for navigation system may be needed to obtain certifications from legal authorities to expand UAV applications to new types of mission. Note de contenu : 1- Preliminaries
2- VDM-based navigation framework
3- Results and analyses
4- Conclusion remarksNuméro de notice : 21988 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : Thèse Doctorat : : EPFL : 2018 nature-HAL : Thèse DOI : 10.5075/epfl-thesis-8494 En ligne : https://www.sgc.ethz.ch/publications.html Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91986 Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 21988-01 30.70 Livre Centre de documentation Géodésie Disponible Multipath detection with the combination of SNR measurements – Example from urban environment / Peter Spanik in Geodesy and cartography, vol 66 n° 2 (December 2017)
[article]
Titre : Multipath detection with the combination of SNR measurements – Example from urban environment Type de document : Article/Communication Auteurs : Peter Spanik, Auteur ; Jan Hefty, Auteur Année de publication : 2017 Article en page(s) : pp 305 - 316 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] données Galileo
[Termes IGN] données GLONASS
[Termes IGN] données GPS
[Termes IGN] mesurage de phase
[Termes IGN] milieu urbain
[Termes IGN] rapport signal sur bruit
[Termes IGN] trajet multipleRésumé : (auteur) Multipath is one of the most severe station-dependent error sources in both static and kinematic positioning. Relatively new and simple detection technique using the Signal-to-Noise (SNR) measurements on three frequencies will be presented based on idea of Strode and Groves. Exploitation of SNR measurements is beneficial especially for their unambiguous character. Method is based on the fact that SNR values are closely linked with estimation of pseudo-ranges and phase measurements during signal correlation processing. Due to this connection, combination of SNR values can be used to detect anomalous behavior in received signal, however some kind of calibration in low multipath environment has to be done previously. In case of multipath, phase measurements on different frequencies will not be affected in the same manner. Specular multipath, e.g. from building wall introduces additional path delay which is interpreted differently on each of the used carrier, due to different wavelengths. Experimental results of multipath detection in urban environment will be presented. Originally proposed method is designed to work with three different frequencies in each epoch, thus only utilization of GPS Block II-F and Galileo satellites is possible. Simplification of detection statistics to use only two frequencies is made and results using GPS and GLONASS systems are presented along with results obtained using original formula. Numéro de notice : A2017-789 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/geocart-2017-0020 En ligne : https://doi.org/10.1515/geocart-2017-0020 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89101
in Geodesy and cartography > vol 66 n° 2 (December 2017) . - pp 305 - 316[article]Robust wavelet-based inertial sensor error mitigation for tightly coupled GPS/BDS/INS integration during signal outages / Jian Wang in Survey review, vol 49 n° 357 (December 2017)
[article]
Titre : Robust wavelet-based inertial sensor error mitigation for tightly coupled GPS/BDS/INS integration during signal outages Type de document : Article/Communication Auteurs : Jian Wang, Auteur ; Houzeng Han, Auteur ; Xiaolin Meng, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 419 - 427 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] BDS-INS
[Termes IGN] correction du signal
[Termes IGN] double différence
[Termes IGN] filtrage du bruit
[Termes IGN] filtre de Kalman
[Termes IGN] GPS-INS
[Termes IGN] méthode robusteRésumé : (auteur) This paper proposes a robust wavelet-based tightly coupled Global Positioning System (GPS)/ Beidou Navigation Satellite System (BDS)/Inertial Navigation System (INS) integration scheme aiming to improve the overall position accuracy during signal outages. A robust wavelet denoising model based on α-trimmed mean filter demonstrates its effectiveness on noise reduction and gross error elimination of inertial sensor raw data. Thereafter, a robust wavelet-based tightly coupled GPS/BDS/INS integration scheme is proposed, and GPS/BDS double-difference (DD) carrier-phase and pseudorange measurements are introduced to build a 27-state tightly coupled GPS/BDS/INS integration equation. The extended Kalman filter (EKF) has been designed for state estimation, and the inclusion of BDS enhances the satellite geometric strength of the whole navigation system. A field vehicle test indicates the position accuracy of five simulated GPS/BDS outages can be improved by about 7, 16, and 33% for north, east, and up components with the proposed scheme compared to standard integration scheme, and gross errors have been detected and eliminated with the new integration scheme. The authors also find that the BDS phase residual is larger than GPS and satellite dependent in the tightly coupled GPS/BDS/INS integrated navigation system. Numéro de notice : A2017-756 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2016.1190162 En ligne : https://doi.org/10.1080/00396265.2016.1190162 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89110
in Survey review > vol 49 n° 357 (December 2017) . - pp 419 - 427[article]Single image dehazing via an improved atmospheric scattering model / Mingye Ju in The Visual Computer, vol 33 n° 12 (December 2017)
[article]
Titre : Single image dehazing via an improved atmospheric scattering model Type de document : Article/Communication Auteurs : Mingye Ju, Auteur ; Dengyin Zhang, Auteur ; Xuemei Wang, Auteur Année de publication : 2017 Article en page(s) : pp 1613 - 1625 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] brouillard
[Termes IGN] diffusion du rayonnement
[Termes IGN] effet atmosphérique
[Termes IGN] image isolée
[Termes IGN] scène urbaine
[Termes IGN] segmentation d'imageRésumé : (Auteur) Under foggy or hazy weather conditions, the visibility and color fidelity of outdoor images are prone to degradation. Hazy images can be the cause of serious errors in many computer vision systems. Consequently, image haze removal has practical significance for real-world applications. In this study, we first analyze the inherent weaknesses of the atmospheric scattering model and propose an improvement to address those weaknesses. Then, we present a fast image haze removal algorithm based on the improved model. In our proposed method, the input image is partitioned into several scenes based on the haze thickness. Next, averaging and erosion operations calculate the rough scene luminance map in a scene-wise manner. We obtain the rough scene transmission map by maximizing the contrast in each scene and then develop a way to gently remove the haze using an adaptive method for adjusting scene transmission based on scene features. In addition, we propose a guided total variation model for edge optimization, so as to prevent from the block effect as well as to eliminate the negative effect from the wrong scene segmentation results. The experimental results demonstrate that our method is effective in solving a series of common problems, including uneven illuminance, overenhanced and oversaturated images, and so forth. Moreover, our method outperforms most current dehazing algorithms in terms of visual effects, universality, and processing speed. Numéro de notice : A2017-715 Affiliation des auteurs : non IGN Thématique : IMAGERIE/INFORMATIQUE Nature : Article DOI : 10.1007/s00371-016-1305-1 En ligne : https://doi.org/10.1007/s00371-016-1305-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88099
in The Visual Computer > vol 33 n° 12 (December 2017) . - pp 1613 - 1625[article]Small reflectors for ground motion monitoring with InSAR / Prabu Dheenathayalan in IEEE Transactions on geoscience and remote sensing, vol 55 n° 12 (December 2017)
[article]
Titre : Small reflectors for ground motion monitoring with InSAR Type de document : Article/Communication Auteurs : Prabu Dheenathayalan, Auteur ; Miguel Caro Cuenca, Auteur ; Peter Hoogeboom, Auteur ; Ramon F. Hanssen, Auteur Année de publication : 2017 Article en page(s) : pp 6703 - 6712 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] coin réflecteur
[Termes IGN] déformation de la croute terrestre
[Termes IGN] fouillis d'échos
[Termes IGN] interféromètrie par radar à antenne synthétique
[Termes IGN] rapport signal sur bruit
[Termes IGN] surveillance géologiqueRésumé : (Auteur) In recent years, synthetic aperture radar interferometry has become a recognized geodetic tool for observing ground motion. For monitoring areas with low density of coherent targets, artificial corner reflectors (CRs) are usually introduced. The required size of a reflector depends on radar wavelength and resolution and on the required deformation accuracy. CRs have been traditionally used to provide a high signal-to-clutter ratio (SCR). However, large dimensions can make the reflector bulky, difficult to install and maintain. Furthermore, if a large number of reflectors are needed for long infrastructure, such as vegetation-covered dikes, the total price of the reflectors can become unaffordable. On the other hand, small reflectors have the advantage of easy installation and low cost. In this paper, we design and study the use of small reflectors with low SCR for ground motion monitoring. In addition, we propose a new closed-form expression to estimate the interferometric phase precision of resolution cells containing a (strong or weak) point target and a clutter. Through experiments, we demonstrate that the small reflectors can also deliver displacement estimates with an accuracy of a few millimeters. To achieve this, we apply a filtering method for reducing clutter noise. Numéro de notice : A2017-765 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2017.2731424 En ligne : https://doi.org/10.1109/TGRS.2017.2731424 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88802
in IEEE Transactions on geoscience and remote sensing > vol 55 n° 12 (December 2017) . - pp 6703 - 6712[article]Hybrid image noise reduction algorithm based on genetic ant colony and PCNN / Chong Shen in The Visual Computer, vol 33 n° 11 (November 2017)PermalinkImproved atmospheric correction and chlorophyll-a remote sensing models for turbid waters in a dusty environment / Maryam R. Al Shehhi in ISPRS Journal of photogrammetry and remote sensing, vol 133 (November 2017)PermalinkIonospheric and receiver DCB-constrained multi-GNSS single-frequency PPP integrated with MEMS inertial measurements / Zhouzheng Gao in Journal of geodesy, vol 91 n° 11 (November 2017)PermalinkPrecise orbit determination of the Fengyun-3C satellite using onboard GPS and BDS observations / Min Li in Journal of geodesy, vol 91 n° 11 (November 2017)Permalink3D building model-assisted snapshot positioning algorithm / Rakesh Kumar in GPS solutions, vol 21 n° 4 (October 2017)PermalinkCharacterizing noise in daily GPS position time series with overlapping Hadamard variance and maximum likelihood estimation / Chang Xu in Survey review, vol 49 n° 355 (October 2017)PermalinkGLONASS inter-frequency phase bias rate estimation by single-epoch or Kalman filter algorithm / Yi Bin Yao in GPS solutions, vol 21 n° 4 (October 2017)PermalinkInitial assessment of the COMPASS/BeiDou-3 : new-generation navigation signals / Xiaohong Zhang in Journal of geodesy, vol 91 n° 10 (October 2017)PermalinkIonospheric correction using NTCM driven by GPS Klobuchar coefficients for GNSS applications / M.M. Hoque in GPS solutions, vol 21 n° 4 (October 2017)PermalinkAtmospheric correction over coastal waters using multilayer neural networks / Yongzhen Fan in Remote sensing of environment, vol 199 (15 September 2017)PermalinkAssessing the performance of multi-GNSS precise point positioning in Asia-Pacific region / X. Zhao in Survey review, vol 49 n° 354 (September 2017)PermalinkDenoising of natural images through robust wavelet thresholding and genetic programming / Asem Khmag in The Visual Computer, vol 33 n°9 (September 2017)PermalinkDetermination of the ionospheric foF2 using a stand-alone GPS receiver / Dudy D Wijaya in Journal of geodesy, vol 91 n° 9 (September 2017)PermalinkA fresh look at GNSS anti-jamming / Daniele Borio in Inside GNSS, vol 12 n° 5 (September - October 2017)PermalinkRecurrent neural networks to correct satellite image classification maps / Emmanuel Maggiori in IEEE Transactions on geoscience and remote sensing, vol 55 n° 9 (September 2017)PermalinkVisual analytics of time-varying multivariate ionospheric scintillation data / Aurea Soriano-Vargas in Computers and graphics, vol 68 (November 2017)PermalinkModeling canopy reflectance over sloping terrain based on path length correction / Gaofei Yin in IEEE Transactions on geoscience and remote sensing, vol 55 n° 8 (August 2017)PermalinkParallax-tolerant aerial image georegistration and efficient camera pose refinement—without piecewise homographies / Hadi AliAkbarpour in IEEE Transactions on geoscience and remote sensing, vol 55 n° 8 (August 2017)PermalinkEnhanced resolution stripmap mode using dynamic metasurface antennas / Andreas Pedross-Engel in IEEE Transactions on geoscience and remote sensing, vol 55 n° 7 (July 2017)PermalinkGold – A novel deconvolution algorithm with optimization for waveform LiDAR processing / Tan Zhou in ISPRS Journal of photogrammetry and remote sensing, vol 129 (July 2017)Permalink