21 research outputs found
Wireless Localization Systems: Statistical Modeling and Algorithm Design
Wireless localization systems are essential for emerging applications that rely on
context-awareness, especially in civil, logistic, and security sectors. Accurate localization in indoor environments is still a challenge and triggers a fervent research
activity worldwide. The performance of such systems relies on the quality of range
measurements gathered by processing wireless signals within the sensors composing
the localization system. Such range estimates serve as observations for the target
position inference. The quality of range estimates depends on the network intrinsic
properties and signal processing techniques. Therefore, the system design and analysis call for the statistical modeling of range information and the algorithm design
for ranging, localization and tracking. The main objectives of this thesis are: (i) the
derivation of statistical models and (ii) the design of algorithms for different wire-
less localization systems, with particular regard to passive and semi-passive systems
(i.e., active radar systems, passive radar systems, and radio frequency identification
systems). Statistical models for the range information are derived, low-complexity
algorithms with soft-decision and hard-decision are proposed, and several wideband
localization systems have been analyzed. The research activity has been conducted
also within the framework of different projects in collaboration with companies and
other universities, and within a one-year-long research period at Massachusetts Institute of Technology, Cambridge, MA, USA. The analysis of system performance,
the derived models, and the proposed algorithms are validated considering different case studies in realistic scenarios and also using the results obtained under the
aforementioned projects
Beyond 100: The Next Century in Geodesy
This open access book contains 30 peer-reviewed papers based on presentations at the 27th General Assembly of the International Union of Geodesy and Geophysics (IUGG). The meeting was held from July 8 to 18, 2019 in Montreal, Canada, with the theme being the celebration of the centennial of the establishment of the IUGG. The centennial was also a good opportunity to look forward to the next century, as reflected in the title of this volume. The papers in this volume represent a cross-section of present activity in geodesy, and highlight the future directions in the field as we begin the second century of the IUGG. During the meeting, the International Association of Geodesy (IAG) organized one Union Symposium, 6 IAG Symposia, 7 Joint Symposia with other associations, and 20 business meetings. In addition, IAG co-sponsored 8 Union Symposia and 15 Joint Symposia. In total, 3952 participants registered, 437 of them with IAG priority. In total, there were 234 symposia and 18 Workshops with 4580 presentations, of which 469 were in IAG-associated symposia. ; This volume will publish papers based on International Association of Geodesy (IAG) -related presentations made at the International Association of Geodesy at the 27th IUGG General Assembly, Montreal, July 2019. It will include papers associated with all of the IAG and joint symposia from the meeting, which span all aspects of modern geodesy, and linkages to earth and environmental sciences. It continues the long-running IAG Symposia Series
Beyond 100: The Next Century in Geodesy
This open access book contains 30 peer-reviewed papers based on presentations at the 27th General Assembly of the International Union of Geodesy and Geophysics (IUGG). The meeting was held from July 8 to 18, 2019 in Montreal, Canada, with the theme being the celebration of the centennial of the establishment of the IUGG. The centennial was also a good opportunity to look forward to the next century, as reflected in the title of this volume. The papers in this volume represent a cross-section of present activity in geodesy, and highlight the future directions in the field as we begin the second century of the IUGG. During the meeting, the International Association of Geodesy (IAG) organized one Union Symposium, 6 IAG Symposia, 7 Joint Symposia with other associations, and 20 business meetings. In addition, IAG co-sponsored 8 Union Symposia and 15 Joint Symposia. In total, 3952 participants registered, 437 of them with IAG priority. In total, there were 234 symposia and 18 Workshops with 4580 presentations, of which 469 were in IAG-associated symposia. ; This volume will publish papers based on International Association of Geodesy (IAG) -related presentations made at the International Association of Geodesy at the 27th IUGG General Assembly, Montreal, July 2019. It will include papers associated with all of the IAG and joint symposia from the meeting, which span all aspects of modern geodesy, and linkages to earth and environmental sciences. It continues the long-running IAG Symposia Series
Abstracts on Radio Direction Finding (1899 - 1995)
The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography).
Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM.
The contents of these files are:
1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format];
2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format];
3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion
Recommended from our members
NBS monograph
From Abstract: "This is a tutorial Monograph describing various aspects of time and frequency (T/F). Included are chapters relating to elemental concepts of precise time and frequency; basic principles of quartz oscillators and atomic frequency standards; historical review, recent progress, and current status of atomic frequency standards; promising areas for developing future primary frequency standards; relevance of frequency standards to other areas of metrology including a unified standard concept; statistics of T/F data analysis coupled with the theory and construction of the NBS atomic time scale; an overview of T/F dissemination techniques; and the standards of T/F in the USA. The Monograph addresses both the specialist in the field as well as those desiring basic information about time and frequency.
Application de la réflectométrie GNSS à l'étude des redistributions des masses d'eau à la surface de la Terre
GNSS reflectometry (or GNSS-R) is an original and opportunistic remote sensing technique based on the analysis of the electromagnetic waves continuously emitted by GNSS positioning systems satellites (GPS, GLONASS, etc.) that are captured by an antenna after reflection on the Earthâs surface. These signals interact with the reflective surface and hence contain information about its properties. When they reach the antenna, the reflected waves interfere with those coming directly from the satellites. This interference is particularly visible in the signal-to-noise ratio (SNR) parameter recorded by conventional GNSS stations. It is thus possible to reverse the SNR time series to estimate the reflective surface characteristics. If the feasibility and usefulness of thismethod are well established, the implementation of this technique poses a number of issues. Namely the spatio-temporal accuracies and resolutions that can be achieved and thus what geophysical observables are accessible.The aim of my PhD research work is to provide some answers on this point, focusing on the methodological development and geophysical exploitation of the SNR measurements performed by conventional GNSS stations. I focused on the estimation of variations in the antenna height relative to the reflecting surface (altimetry) and on the soil moisture in continental areas. The SNR data inversion method that I propose has been successfully applied to determine local variations of: (1) the sea level near the Cordouan lighthouse (not far from Bordeaux, France) from March 3 to May 31, 2013, where the main tidal periods and waves have been clearly identified ; and (2) the soil moisture in an agricultural plot near Toulouse, France, from February 5 to March 15, 2014. My method eliminates some restrictions imposed in earlier work, where the velocity of the vertical variation of the reflective surface was assumed to be negligible. Furthermore, I developed a simulator that allowed me to assess the influence of several parameters (troposphere, satellite elevation angle, antenna height, local relief, etc.) on the path of the reflected waves and hence on the position of the reflection points. My work shows that GNSS-R is a powerful alternative and a significant complement to the current measurement techniques, establishing a link between the different temporal and spatial resolutions currently achieved by conventional tools (sensors, radar, scatterometer, etc.). This technique offers the major advantage of being based on already-developed and sustainable satellites networks, and can be applied to any GNSS geodetic station, including permanent networks (e.g., the French RGP). Therefore, by installing a processing chain of these SNR acquisitions, data from hundreds of pre-existing stations could be used to make local altimetry measurements in coastal areas or to estimate soil moisture for inland antennas.La rĂ©flectomĂ©trie GNSS (ou GNSS-R) est une technique de tĂ©lĂ©dĂ©tection originale et pportuniste qui consiste Ă analyser les ondes Ă©lectromagnĂ©tiques Ă©mises en continu par la soixantaine de satellites des systĂšmes de positionnement GNSS (GPS, GLONASS, etc.), qui sont captĂ©es par une antenne aprĂšs rĂ©flexion sur la surface terrestre. Ces signaux interagissent avec la surface rĂ©flĂ©chissante et contiennent donc des informations sur ses propriĂ©tĂ©s. Au niveau de lâantenne, les ondes rĂ©flĂ©chies interfĂšrent avec celles arrivant directement des satellites. Ces interfĂ©rences sont particuliĂšrement visibles dans le rapport signal-sur-bruit (SNR, i.e., Signal-to-Noise Ratio), paramĂštre enregistrĂ© par une station GNSS classique. Il est ainsi possible dâinverser les sĂ©ries temporelles du SNR pour estimer des caractĂ©ristiques du milieu rĂ©flĂ©chissant. Si la faisabilitĂ© et lâintĂ©rĂȘt de cette mĂ©thode ne sont plus Ă dĂ©montrer, la mise en oeuvre de cette technique pose un certain nombre de problĂšmes, Ă savoir quelles prĂ©cisions et rĂ©solutions spatio-temporelles peuvent ĂȘtre atteintes, et par consĂ©quent, quels sont les observables gĂ©ophysiques accessibles.Mon travail de thĂšse a pour objectif dâapporter des Ă©lĂ©ments de rĂ©ponse sur ce point, et est axĂ© sur le dĂ©veloppement mĂ©thodologique et lâexploitation gĂ©ophysique des mesures de SNR rĂ©alisĂ©es par des stations GNSS classiques.Je me suis focalisĂ© sur lâestimation des variations de hauteur de lâantenne par rapport Ă la surfacerĂ©flĂ©chissante (altimĂ©trie) et de lâhumiditĂ© du sol en domaine continental. La mĂ©thode dâinversion des mesures SNR que je propose a Ă©tĂ© appliquĂ©e avec succĂšs pour dĂ©terminer les variations locales de : (1) la hauteur de la mer au voisinage du phare de Cordouan du 3 mars au 31 mai 2013 oĂč les ondes de marĂ©es et la houle ont pu ĂȘtre parfaitement identifiĂ©es ; et (2) lâhumiditĂ© du sol dans un champ agricole Ă proximitĂ© de Toulouse, du 5 fĂ©vrier au 15 mars 2014. Ma mĂ©thode permet de sâaffranchir de certaines restrictions imposĂ©es jusquâĂ prĂ©sent dans les travaux antĂ©rieurs, oĂč la vitesse de variation verticale de la surface de rĂ©flexion Ă©tait supposĂ©e nĂ©gligeable. De plus, jâai dĂ©veloppĂ© un simulateur qui mâa permis de tester lâinfluence de nombreux paramĂštres (troposphĂšre, angle dâĂ©lĂ©vation du satellite, hauteur dâantenne, relief local, etc.) sur la trajectoire des ondes rĂ©flĂ©chies et donc sur la position des points de rĂ©flexion. Mon travail de thĂšse montre que le GNSS-R est une alternative performante et un complĂ©ment non nĂ©gligeable aux techniques de mesure actuelles, en faisant le lien entre les diffĂ©rentes rĂ©solutions temporelles et spatiales actuellement atteintes par les outils classiques (sondes, radar, diffusiomĂštres, etc.). Cette technique offre lâavantage majeur dâĂȘtre basĂ© sur un rĂ©seau de satellites dĂ©jĂ en place et pĂ©renne, et est applicable Ă nâimporte quelle station GNSS gĂ©odĂ©sique, notamment celles des rĂ©seaux permanents (e.g., le RGP français). Ainsi, en installant une chaĂźne de traitement de ces acquisitions de SNR en domaine cĂŽtier, il serait possible dâutiliser les mesures continues des centaines de stations prĂ©-existantes, et dâenvisager de rĂ©aliser des mesures altimĂ©triques Ă lâĂ©chelle locale, ou de mesurer lâhumiditĂ© du sol pour les antennes situĂ©es Ă lâintĂ©rieur des terres
Proceedings of the 19th Sound and Music Computing Conference
Proceedings of the 19th Sound and Music Computing Conference - June 5-12, 2022 - Saint-Ătienne (France).
https://smc22.grame.f