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Assessing data from permanent GNSS stations in Algeria / Hassen Abdellaoui in Bulletin des sciences géographiques, n° 31 (2017 - 2018)
[article]
Titre : Assessing data from permanent GNSS stations in Algeria Type de document : Article/Communication Auteurs : Hassen Abdellaoui, Auteur ; Naima Zaourar, Auteur ; Mohamed Aïssa Meslem, Auteur Année de publication : 2018 Article en page(s) : pp 2 - 12 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] Algérie
[Termes IGN] données GNSS
[Termes IGN] interférence
[Termes IGN] réseau géodésique permanent
[Termes IGN] stabilité dans le temps
[Termes IGN] station permanente
[Termes IGN] trajet multipleRésumé : (Auteur) Un projet d'envergure nationale est mené depuis quelques années dans le but d'améliorer l'infrastructure géodésique par la mise en place d'un vaste réseau de stations de référence opérant en continu (CORS) GNSS en temps réel. Dans cette perspective, une étude a été réalisée dans le but de sélectionner des sites éligibles de l'infrastructure de réseau GNSS/CORS. Les critères de sélection techniques étaient essentiellement basés sur l'évaluation des données GNSS reçues par les sites GNSS déjà opérationnels. Deux stations ont été sélectionnées pour réaliser cette recherche fondée sur l'évaluation des interférences de signaux et de la propagation par trajets multiples et sur l'analyse de la stabilité du monument par le post-traitement des données GNSS fournies par ces sites GNSS, qui sont situés au nord d'Alger et au sud de Ouargla, à savoir DZAL et OGLA respectivement. Numéro de notice : A2018-560 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92151
in Bulletin des sciences géographiques > n° 31 (2017 - 2018) . - pp 2 - 12[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 253-2018011 RAB Revue Centre de documentation En réserve L003 Disponible Parameter estimation with GNSS-reflectometry and GNSS synthetic aperture techniques / Miguel Angel Ribot Sanfelix (2018)
Titre : Parameter estimation with GNSS-reflectometry and GNSS synthetic aperture techniques Type de document : Thèse/HDR Auteurs : Miguel Angel Ribot Sanfelix, Auteur ; Pierre-André Farine, Directeur de thèse ; Cyril Botteron, Directeur de thèse Editeur : Lausanne : Ecole Polytechnique Fédérale de Lausanne EPFL Année de publication : 2018 Importance : 187 p. Format : 21 x 30 cm Note générale : bibliographie
Thèse présentée à l'Ecole Polytechnique Fédérale de Lausanne pour l'obtention du grade de Docteur ès SciencesLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] classification par maximum de vraisemblance
[Termes IGN] correction du trajet multiple
[Termes IGN] erreur de positionnement
[Termes IGN] filtre de Kalman
[Termes IGN] interférence
[Termes IGN] ligne de visée
[Termes IGN] phase
[Termes IGN] récepteur GNSS
[Termes IGN] réflectométrie par GNSS
[Termes IGN] signal GNSS
[Termes IGN] signal GPSRésumé : (auteur) Aside from intentional interference, multipath is the most significant error source for Global Navigation Satellite Systems (GNSS) receivers in many operational scenarios. In this thesis, we study the multipath estimation from two different perspectives: to retrieve useful information from it using GNSS-Reflectometry (GNSS-R) techniques; and to mitigate its effects or to estimate its direction-of-arrival (DOA) as well as the line-of-sight (LOS) signal’s using synthetic aperture (SA) processing. The first part of the thesis focuses on precision bounds for GNSS-R techniques for groundbased receivers, in scenarios where a single antenna simultaneously receives the LOS signal and a specular reflection. First, we derive the Cramér-Rao bound (CRB) of the receiver’s
height and the reflection coefficient, with the latter depending on the surface’s electrical properties. More specifically, we propose a CRB derivation applicable to GNSS-R techniques that make use of the phase information and long observation times, such as the interference pattern technique (IPT). The derivation is based on the parameter transformation of the Fisher information matrix. We study the dependence of the computed CRB on the scenario and the receiver bandwidth. The CRB results for the simulated scenarios are consistent with
the precision reported for many GNSS-R techniques used in these scenarios. The proposed CRB is meant to benchmark and compare new and existing techniques. Besides the derived CRB, we propose an algorithm to obtain the maximum-likelihood (ML) estimator of the parameters of interest with the IPT: the segmented ML estimator (SML). The SML transforms a complex multivariate optimization problem into multiple simpler ones
by dividing the parameter search space taking advantage of the cost function’s particular structure. The SML is validated with simulated signal and asymptotically cross-validates the CRB results. The second part of the thesis is devoted to the study of the SA processing of GNSS signals. The goal is to estimate the DOA of the signals received, and mitigate errors in the navigation solution caused by interfering signals, such as multipath. We start by deriving the CRB for the SA context, as a function of the antenna trajectory. This CRB considers the effect of the antenna complex gain, and we show in simulations that it is possible to achieve meaningful DOA estimation only by changing the antenna’s orientation. We continue by proposing a development framework built upon a signal tracking architecture integrating SA processing. Before any SA processing, it is necessary to estimate and compensate any carrier phase contribution not related to the antenna motion. To do so, we propose two
new sequential techniques based on the extended Kalman filter (EKF). Also, we develop an open-loop version of the proposed SA tracking architecture, more robust than its closed-loop counterpart. Finally, we validate the proposed architecture and SA-based techniques with synthetic GPS signals at first, and then with real signals, recorded using an antenna mounted on a mechanical rotating arm. The obtained results validate the implemented techniques and show how the proposed SA architecture can ultimately mitigate the position bias error observed in environments with severe multipath interference.Note de contenu : 1- Introduction
2- GNSS-Reflectomery and Synthetic Aperture Processing: An Overview
3- Parameter Estimation in GNSS-Reflectometry Scenarios with Coherent Reflection
4- Spatial Filtering of GNSS Signals with Synthetic Aperture Processing
5- ConclusionsNuméro de notice : 25793 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : Thèse de Doctorat : Sciences : Lausanne : 2018 En ligne : https://infoscience.epfl.ch/record/253111?ln=fr Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95019
Titre : Physics of oscillations and waves Type de document : Monographie Auteurs : Arnt Inge Vistnes, Auteur Editeur : Springer Nature Année de publication : 2018 Importance : 594 p. Format : 16 x 24 cm ISBN/ISSN/EAN : 978-3-319-72314-3 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Physique
[Termes IGN] diffraction
[Termes IGN] interférence
[Termes IGN] longueur d'onde
[Termes IGN] onde
[Termes IGN] onde acoustique
[Termes IGN] onde électromagnétique
[Termes IGN] onde lumineuse
[Termes IGN] oscillation
[Termes IGN] phase
[Termes IGN] transformation de Fourier
[Termes IGN] transformation en ondelettesRésumé : (éditeur) In this textbook a combination of standard mathematics and modern numerical methods is used to describe a wide range of natural wave phenomena, such as sound, light and water waves, particularly in specific popular contexts, e.g. colors or the acoustics of musical instruments. It introduces the reader to the basic physical principles that allow the description of the oscillatory motion of matter and classical fields, as well as resulting concepts including interference, diffraction, and coherence. Numerical methods offer new scientific insights and make it possible to handle interesting cases that can’t readily be addressed using analytical mathematics; this holds true not only for problem solving but also for the description of phenomena. Essential physical parameters are brought more into focus, rather than concentrating on the details of which mathematical trick should be used to obtain a certain solution. Readers will learn how time-resolved frequency analysis offers a deeper understanding of the interplay between frequency and time, which is relevant to many phenomena involving oscillations and waves. Attention is also drawn to common misconceptions resulting from uncritical use of the Fourier transform. The book offers an ideal guide for upper-level undergraduate physics students and will also benefit physics instructors. Program codes in Matlab and Python, together with interesting files for use in the problems, are provided as free supplementary material. Note de contenu : 1- Introduction
2- Free and Damped Oscillations
3- Forced Oscillations and Resonance
4- Forced Oscillations and Resonance
5- Fourier Analysis
6- Waves
7- Sound
8- Dispersion and Waves on Water
9- Electromagnetic Waves
10- Reflection, Transmission and Polarization
11- Measurements of Light, Dispersion, Colours
12- Geometric Optics
13- Interference—Diffraction
14- Wavelet Transform
15- Coherence, Dipole Radiation and Laser
16- Skin Depth and WaveguidesNuméro de notice : 25817 Affiliation des auteurs : non IGN Nature : Monographie En ligne : https://doi.org/10.1007/978-3-319-72314-3 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95082 A fresh look at GNSS anti-jamming / Daniele Borio in Inside GNSS, vol 12 n° 5 (September - October 2017)
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Titre : A fresh look at GNSS anti-jamming Type de document : Article/Communication Auteurs : Daniele Borio, Auteur ; Pau Closas, Auteur Année de publication : 2017 Article en page(s) : pp 54 - 61 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] anti-leurrage
[Termes IGN] brouillage
[Termes IGN] estimation de position
[Termes IGN] interférence
[Termes IGN] méthode robuste
[Termes IGN] mitigation
[Termes IGN] signal GNSSRésumé : (auteur) Although strong jamming can overwhelm much weaker GNSS signals, receiver performance can be significantly improved by implementing interference mitigation techniques. With this article we briefly discuss the most common approaches for interference mitigation and frame them with respect to the principles of Interference Cancellation (IC) and robust estimation. Additionally, we present initial results obtained using Robust Transform Domain (RTD) mitigation techniques. These techniques provide effective alternatives to Transform Domain excision, enabling receiver operations in the close proximity of a jammer. Numéro de notice : A2017-583 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : http://www.insidegnss.com/node/5618 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86718
in Inside GNSS > vol 12 n° 5 (September - October 2017) . - pp 54 - 61[article]GNSS antenna caused near-field interference effect in Precise Point Positioning results / Karol Dawidowicz in Artificial satellites, vol 52 n° 2 (June 2017)
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Titre : GNSS antenna caused near-field interference effect in Precise Point Positioning results Type de document : Article/Communication Auteurs : Karol Dawidowicz, Auteur ; Radosław Baryła, Auteur Année de publication : 2017 Article en page(s) : pp 27 - 40 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] antenne GNSS
[Termes IGN] erreur
[Termes IGN] interférence
[Termes IGN] positionnement ponctuel précis
[Termes IGN] précision millimétriqueRésumé : (Auteur) Results of long-term static GNSS observation processing adjustment prove that the often assumed “averaging multipath effect due to extended observation periods” does not actually apply. It is instead visible a bias that falsifies the coordinate estimation. The comparisons between the height difference measured with a geometrical precise leveling and the height difference provided by GNSS clearly verify the impact of the near-field multipath effect.
The aim of this paper is analysis the near-field interference effect with respect to the coordinate domain. We demonstrate that the way of antennas mounting during observation campaign (distance from nearest antennas) can cause visible changes in pseudo-kinematic precise point positioning results. GNSS measured height differences comparison revealed that bias of up to 3 mm can be noticed in Up component when some object (additional GNSS antenna) was placed in radiating near-field region of measuring antenna. Additionally, for both processing scenario (GPS and GPS/GLONASS) the scattering of results clearly increased when additional antenna crosses radiating near-field region of measuring antenna. It is especially true for big choke ring antennas. In short session (15, 30 min.) the standard deviation was about twice bigger in comparison to scenario without additional antenna. When we used typical surveying antennas (short near-field region radius) the effect is almost invisible. In this case it can be observed the standard deviation increase of about 20%. On the other hand we found that surveying antennas are generally characterized by lower accuracy than choke ring antennas. The standard deviation obtained on point with this type of antenna was bigger in all processing scenarios (in comparison to standard deviation obtained on point with choke ring antenna).Numéro de notice : A2017-593 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/arsa-2017-0004 En ligne : https://doi.org/10.1515/arsa-2017-0004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86801
in Artificial satellites > vol 52 n° 2 (June 2017) . - pp 27 - 40[article]Double take : mitigating interference with a dual-polarized antenna array in a real environment / Matteo Sgammini in GPS world, vol 28 n° 2 (February 2017)PermalinkInterference localization from space: part 2 applications / Luca Canzian in Inside GNSS, vol 12 n° 1 (January - February 2017)PermalinkPermalinkSpringer handbook of Global Navigation Satellite Systems / Peter J.G. Teunissen (2017)PermalinkInterference localization from space: theoretical background / Luca Canzian in Inside GNSS, vol 11 n° 6 (November - December 2016)PermalinkSMAP L-Band microwave radiometer: RFI mitigation prelaunch analysis and first year on-orbit observations / Priscilla N. Mohammed in IEEE Transactions on geoscience and remote sensing, vol 54 n° 10 (October 2016)PermalinkInterference mitigation in the E5A Galileo band using an open-source simulator / Diego Alonso in Inside GNSS, vol 11 n° 4 (July - August 2016)PermalinkListening for RF noise : An analysis of pre-despreading GNSS interference detection techniques / Ali Jafarnia-Jahromi in Inside GNSS, vol 11 n° 3 (May - June 2016)PermalinkFlying safe : GNSS Robustness for Unmanned Aircraft Systems / Joshua Stubbs in GPS world, vol 27 n° 4 (April 2016)PermalinkCombined Architecture : Enhancing Multi-Dimensional Signal Quality in GNSS Receivers / Nunzia Giorgia Ferrara in Inside GNSS, vol 11 n° 2 (March - April 2016)Permalink