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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Conception d'un système d'antennes pour la localisation en temps réel avec réseau de capteurs sans fils. / Conceiving a antenna system for a real-time locating system applied to wireless sensor networks

Barbosa Nogueira, Evanaska Maria 13 December 2013 (has links)
Les systèmes de localisation en temps réel (Real-Time Locating System - RTLS) sont de plus en plus employés dans l'industrie. Ils permettent l'automatisation de diverses tâches telles que l'identification et le suivi des objets au long de la chaîne d'approvisionnement, la surveillance d'équipements dans les usines et la sécurisation des biens. Ces systèmes sont basés sur des capteurs électroniques sans fil à faible puissance et à faible coût avec des antennes intégrées. Dans notre contexte, deux types de capteurs sont utilisés. Les tags de référence sont généralement fixés sur les murs tandis que les tags mobiles sont fixés sur les objets qui doivent être suivis. Notre système RTLS (Real Time Localisation System) exploite la puissance du signal reçu (Received Signal Strength Indication - RSSI) pour calculer la localisation des tags mobiles. Toutefois, la performance de ce système peut être influencée par plusieurs facteurs. Tout d'abord, par rapport à l'antenne, la non-uniformité du diagramme de rayonnement et le non-alignement de la polarisation des antennes peuvent affecter la puissance du signal reçu. De plus, l'impact de l'environnement résulte sur des multi-trajets qui dégradent la précision de la localisation. Dans la première partie de ce travail, nous proposons une solution pour le tag de référence en utilisant un plan réflecteur en métal pour améliorer son diagramme de rayonnement. Nous avons effectué plusieurs expériences utilisant un logiciel de simulation et nous démontrons que l'utilisation d'un plan réflecteur en métal améliore considérablement la précision de la localisation de notre système. Dans la deuxième partie, nous proposons d'utiliser des techniques de diversité d'antenne pour le tag mobile afin de minimiser les effets des multi-trajets et d'améliorer le diagramme de rayonnement afin de couvrir tout l'espace souhaité pour la localisation. Nos solutions se composent de trois antennes intégrées sur le boîtier en plastique du tag, alliant la diversité de diagramme et de polarisation. Nous proposons une première structure avec trois antennes PIFAs manufacturées et fixées à l'extérieur du boîtier, un deuxième système avec deux antennes IFAs et enfin une antenne patch triangulaire sur un substrat permettant de plier les antennes, de façon à pouvoir rentrer la structure dans le boîtier du tag. Ces systèmes ont été simulés dans différents configurations de scénario afin de valider l'amélioration apportée par nos solutions. Finalement, des expérimentations ont été menées afin de comparer les systèmes proposés dans un environnement réel. Les résultats montrent que l'erreur de localisation a été divisée par un facteur proche de trois par rapport au système d'origine. / Real-Time Locating Systems (RTLS) have been increasingly employed by the industry. They allow the automation of several tasks such to identify and track objects throughout the supply chains, to watch equipment under surveillance in factories and to secure goods. These systems are usually based on low-power and low-cost wireless electronic sensors with integrated antennas. In our context, two types of sensors are used. The reference tags are generally fixed on the walls whereas mobile tags are fixed on objects that must be tracked. In particular, our RTLS uses the Received Signal Strength Indication (RSSI) to compute the location of mobile tags at 2.4GHz frequency band. However, the performance of such system can be influenced by several factors. On the one hand, the non-uniformity of the radiation pattern and the antenna polarization mismatch can affect the received signal power. On the other hand, the impact of the environment results in multipaths, which degrade the localization precision. In the first part of this thesis, we propose an approach based on a metal plane reflector to improve the radiation pattern of reference tags. We performed several experiments using a microwave simulator and we show that the metal plane reflector considerably improves the localization accuracy of our system. In the second part, we propose to use antenna diversity techniques on mobile tags to minimize multipath effects while improving the radiation pattern. Our three solutions are based on integrated antennas fixed on the tag's plastic case, combining pattern and polarization diversity. Firstly, we propose a structure composed of three Planar Inverted-F Antennas (PIFAs) manufactured and fixed outside of the plastic case. Secondly, we propose a system composed of two Inverted-F Antennas (IFAs). Then, we propose a system composed of a triangular patch antenna on a substrate that allows it to be fixed inside the plastic case. We simulated those systems in different scenarios to analyze and validate the localization improvements brought by our solutions. Finally, we performed real experiments to compare the efficiency of the proposed systems in a real environment. Our results show that the localization error was reduced approximately by a factor of three in comparison to the original system.
2

Real time location system for indoor environment

Dahlman, Gustav, Omara, Johan January 2019 (has links)
Fältet inomhuspositionering är en viktig och stor front och är i fortsatt och snabb utveckling inom IoT-teknik och digitalisering av storstäder. Detta arbete är utformat för att hitta och byggaen lämplig teknik för att komprimera olinjäriteter från multipatutbredning. I denna uppsats undersöks olika lokaliseringstekniker och metoder genom en litteraturstudie. Baserat på resultatetav litteraturstudien och en given uppsättning krav designas och implementeras en prototyp. Detresulterande systemet är baserat på UWB-teknik med hjälp av TWR, trilateration och ett kalmanfilter. Prototypen testas i olika miljöer. Resultaten visar att systemet kan detektera taggen i LOSförhållanden samt klara av visa NLOS förhållanden med en noggrannhet på mindre än 1m respektive 4m. Dessa tester inkluderar både distans mätning (1D) och position mätning i ett plan (2D).Dessutom diskuteras en del om hur man ökar prototypens prestanda. / The field of indoor positioning is an important front and in fast and rapid development as therise of IoT and digitization of big cities. This work is designed to find and build an appropriatetechnology to compact nonlinearities from multipath propagation. In this paper various availablelocalization-technologies and methods are examined through a literature study. Based on the resultof the literature study and a given set of requirements, a prototype is designed and implemented.The resulting system is based on UWB technology using TWR, trilateration and a kalman filter.The prototype is tested in various different environments. The results show that the system is ableto successfully locate an object while fulfilling the requirements of this work. Additionally, someideas on how to increase the performance of the prototype is discussed.
3

Infrastruktura pro testování a nasazení real-time lokalizační platformy / Infrastructure for Testing and Deployment of the Real­-Time Localization Platform

Ormoš, Michal January 2020 (has links)
Táto práca je prípadovou štúdiou postupného vývoja a nasadzovania lokačného softwaru v reálnom čase. Cieľom tejto práce je zrýchliť tento proces. Zvolený problém bol vyriešený s konvenčnými testovacími nastrojmi, vlastným nástrojom pre generovanie sieťovej prevádzky lokalizačnej platformy a nástrojmi CI/CD Gitlab. Prínosom tejto práce je zrýchlenie vývoja, zaručenie kvality vyvijaného softwaru a predstavenie spôsobu ako platformu pre lokalizáciu v reálnom čase testovať.
4

Systèmes de localisation en temps réel basés sur les réseaux de communication sans fil

Abid, Mohamed Amine January 2016 (has links)
Des techniques fiables de radiolocalisation s’avèrent indispensables au développement d’un grand nombre de nouveaux systèmes pertinents. Les techniques de localisation basées sur les réseaux de communication sans-fil (WNs) sont particulièrement adéquates aux espaces confinés et fortement urbanisés. Le présent projet de recherche s’intéresse aux systèmes de localisation en temps réel (RTLS) basés sur les technologies de communication sans-fil existantes. Deux nouvelles techniques de radiolocalisation alternatives sont proposées pour améliorer la précision de positionnement des nœuds sans-fil mobiles par rapport aux méthodes conventionnelles basées sur la puissance des signaux reçus (RSS). La première méthode de type géométrique propose une nouvelle métrique de compensation entre les puissances de signaux reçus par rapport à des paires de stations réceptrices fixes. L’avantage de cette technique est de réduire l’effet des variations du milieu de propagation et des puissances d’émission des signaux sur la précision de localisation. La même métrique est sélectionnée pour former les signatures utilisées pour créer la carte radio de l’environnement de localisation durant la phase hors-ligne dans la deuxième méthode de type analyse de situation. Durant la phase de localisation en temps réel, la technique d’acquisition comprimée (CS) est appliquée pour retrouver les positions des nœuds mobiles à partir d’un nombre réduit d’échantillons de signaux reçus en les comparant à la carte radio préétablie. Le calcul d’algèbre multilinéaire proposé dans ce travail permet l’utilisation de ce type de métrique ternaire, équivalemment la différence des temps d’arrivée (TDOA), pour calculer les positions des cibles selon la technique de CS. Les deux méthodes sont ensuite validées par des simulations et des expérimentations effectuées dans des environnements à deux et à trois dimensions. Les expériences ont été menées dans un bâtiment multi-étages (MFB) en utilisant l’infrastructure sans-fil existante pour retrouver conjointement la position et l’étage des cibles en utilisant les techniques proposées. Un exemple emblématique de l’application des RTLS dans les zones urbaines est celui des systèmes de transport intelligents (ITS) pour améliorer la sécurité routière. Ce projet s’intéresse également à la performance d’une application de sécurité des piétons au niveau des intersections routières. L’accomplissement d’un tel système repose sur l’échange fiable, sous des contraintes temporelles sévères, des données de positionnement géographique entre nœuds mobiles pour se tenir mutuellement informés de leurs présences et positions afin de prévenir les risques de collision. Ce projet mène une étude comparative entre deux architectures d’un système ITS permettant la communication entre piétons et véhicules, directement et via une unité de l’infrastructure, conformément aux standards de communication dans les réseaux ad hoc véhiculaires (VANETs).
5

Real-time Location System with Passive RFID for surveillance of trusted objects in a room

Karlsson, Simon January 2010 (has links)
The use of Radio Frequency Identification (RFID) in Real-Time Location Systems (RTLS) in asset management has been in limited use, mainly in large organizations such as hospitals and military. The research in this area is making progress and new solutions with reduced costs with greater resolution are presented by different companies that enable the technology to be used in new operating areas. This thesis is about the development, implementation and integration of a RTLS solution that enables surveillance of the position of keys. The RTLS solution utilizes RTLS hardware to receive the positions of the keys. The report describes how the RTLS hardware is selected and how the software solution is designed and implemented. The report describes also result of how the finished solution with software and hardware cooperates. The most vital problem was to create an efficient zone structure that implements the surveillance hierarchy of the keys. The thesis was conducted at a company (PAAM Systems) that offers solutions in access and asset management. The company aims to use a RTLS in an asset management application for keys. The purpose of this work is to examine the existing solutions on the market that provide a RTLS with passive RFID technology.
6

Using Multilateration and Extended Kalman Filter for Localization of RFID Passive Tag in NLOS

Olayanju, Iyeyinka Damilola, Ojelabi, Olabode Paul January 2010 (has links)
The use of ubiquitous network has made real time tracking of objects, animals and human beings easy through the use of radio frequency identification system (RFID). Localization techniques in RFID rely on accurate estimation of the read range between the reader and the tags. The tags consist of a small chip and a printed antenna which receives from and transmits information to the reader. The range information about the distance between the tag and the reader is obtained from the received signal strength indication (RSSI). Accuracy of the read range using RSSI can be very complicated especially in complicated propagation environment due to the nature and features of the environment. There are different kinds of localisation systems and they are Global Positioning System (GPS) which can be used for accurate outdoor localization; while technologies like artificial vision, ultrasonic signals, infrared and radio frequency signals can be employed for indoor localization. This project focuses on the location estimation in RFID Non Line-of-Sight (NLOS) environment using Real Time Localization System (RTLS) with passive tags, in carrying out passengers and baggage tracking at the airport. Indoor location radio sensing suffers from reflection, refraction and diffractions due to the nature of the environment. This unfavourable phenomenon called multipath leads to delay in the arrival of signal and the strength of signal received by receiving antenna within the propagation channel which in turns affects the RSSI, yielding inaccurate location estimation. RTLS based on time difference of arrival and error compensation technique and extended Kalman filter technique were employed in a NLOS environment to determine the location of tag. The better method for location estimation in a NLOS between the Kalman filtering and extended Kalman filtering is investigated. According to simulation results, the extended Kalman filtering technique is more suitable to be applied to RTLS.
7

Lokalizační služby ve webových aplikacích / Localization Services for Web Applications

Kočan, Tomáš January 2015 (has links)
The aim of this master thesis was to develop an application that would visualize the position of sensors placed indoors. Since the sensors are located in the buildings, geographical maps are not used as basis, but the user has the option to upload his own background in the form of floor plans of rooms, floors, buildings,... For this purpose, application has tools for uploading, managing and editing such plans. The paper also describes how to use the application to monitor the current and past positions of these sensors. Support for these features is provided by several server components consisting of a REST server, WebSocket server, Upload servers and other services. Their design, description, and implementation is also part of this document. In addition, the work describes RTLS (Real-time locating system) technology, architecture, client application and data security.
8

Technologie RFID v ekonomických sektorech. / RFID technology in the economic sectors

Kuchařová, Hana January 2011 (has links)
This thesis is focused on explanation of RFID technology. The first part analyses its historical development, describes the basic elements needed for its operation and standards enabling its spread into the supplier-customer chains. Furthermore are summarized its common applications such as systems for real-time location, traceability and identification of persons. Finally is summarized its usage in particular economic sectors. The end of the thesis is focused on suitable procedures for implementation of RFID technology into the enterprise, with respect to a feasibility of the project, which is determined in the initial study based on the methodology MMDIS.
9

RTLS – the missing link to optimizing Logistics Management?

Hammerin, Karl, Streitenberger, Ramona January 2019 (has links)
The purpose of this thesis was to investigate how potentials of Real-Time Location Systems (RTLS) in relation to Just In Time (JIT) management could be utilized within logistics management. For this, a framework, based on previous research of the interrelations of RTLS and JIT management, is proposed, to assess the effects of RTLS on logistics management, both on a managerial - as well as on an operational level. To answer the proposed research questions, the study followed a deductive and exploratory case study design, which was conducted at a company within the automotive industry. To understand the challenges within logistics management at the case company, interviews, observations, analysis of internal documents and a focus group were used, which allowed for a triangulation of the captured information. The findings and analysis of the data show that on an operational level the challenges within logistics management are related to complex logistic structures, pull strategies with partial push material flows, lack of information and – reliable data, as well as processes reliant on individuals. On the managerial level the findings suggest challenges related to high complexity and space constraints, time constraints, lack of transparency and – data connections, the company's improvement focus, employee attitude and a lack of reliable data. When the challenges were evaluated in relation to the proposed framework, it shows that these challenges would be resolved or counteracted by the benefits RTLS could provide in relation to JIT management. This study thereby supports the positive correlation between RTLS’s potential and JIT in logistics management.
10

Contributions to TOA-based location with wlan

Ciurana Adell, Marc 15 July 2010 (has links)
Location techniques that satisfy the requirements of advanced Location-Based Services (LBS) in environments where GPS fails are needed, therefore accurate indoor positioning is becoming increasingly important. This PhD Thesis is devoted to the research on location of mobile devices employing WLAN (IEEE 802.11). The use of this kind of wireless networks infrastructures for positioning enables a powerful synergy between communications and location and allows solutions with good performances at moderated costs. However the adopted WLAN location methods suffer from important limitations that prevents from applying them to some fields that need more flexible and robust solutions. The main objective of this PhD is exploring precise WLAN location methods that allow overcoming these limitations. The researched methods here are based on measuring the Time Of Arrival (TOA), which is the time that takes the signal propagating from the transmitter to the receiver. TOA-based location works in two stages: ranging and positioning. The ranging consists of estimating the distances between the targeted terminal and several WLAN access points, each distance obtained measuring the TOA and then multiplying it by the speed of the WLAN signal. After that, the positioning takes as inputs the estimated distances and the known coordinates of the involved access points and calculates the position of the terminal by means of a trilateration or tracking algorithm. The key problem is that the characteristics of the IEEE 802.11 protocols difficult to perform accurate TOA measurements. The main challenge that faces the research work reported here is demonstrating the feasibility of achieving this while keeping the modifications over standard WLAN consumer equipment at minimum. The objective of this work can be understood as exploring the current limits of TOA-based methods over WLAN, making contributions that form a complete TOA-based location method that goes a step forward with respect to the other existing proposals. First, research on TOA-based ranging -the key component of TOA-based location methods- is reported. The general adopted approach consists of performing Round Trip Time (RTT) measurements employing IEEE 802.11 MAC frames, taking the maximum advantage of the combination of IEEE 802.11 protocol and WLAN consumer devices mechanisms. After that, the performed research on trilateration/tracking -the second stage of TOA-based location methods- is explained. Finally some performed studies about the achieved location method are presented. Lloc i data Signatura / Actualment existeix la necessitat de disposar de tècniques de localització que satisfacin els requeriments de serveis avançats basats en localització en entorns on GPS no està disponible, de manera que el posicionament precís en interiors d’edificis és cada vegada més important. Aquesta tesi doctoral està dedicada a la investigació sobre la localització de dispositius mòbils que utilitzen WLAN (IEEE 802.11). L'ús d'aquest tipus de xarxes sense fils per al posicionament permet una profitosa sinèrgia entre les comunicacions i la localització i permet solucions amb un bon rendiment a un cost moderat. No obstant això, els mètodes basats WLAN proposats fins el moment pateixen de limitacions importants que impedeix la seva aplicació a alguns camps que requereixen solucions més flexibles i robustes. L'objectiu principal d'aquesta tesi és explorar mètodes de localització precisa WLAN que permetin superar aquestes limitacions. Els mètodes que s’han investigat durant la tesi es basen en la mesura del time of arrival (TOA), que és el temps que tarda el senyal en propagar-se des del transmissor fins al receptor. En les tècniques de posicionament basades en TOA s’hi poden diferenciar dues fases: ranging i posicionament. El ranging consisteix en l’estimació de distàncies entre el terminal a localitzar i diversos punts d'accés WLAN; cada estimació de distància s’obté mesurant el TOA i multiplicant-lo després per la velocitat de propagació del senyal IEEE 802.11. Un cop fet això, el posicionament pren com a inputs les distàncies estimades per a, conegudes les coordenades dels punts d'accés involucrats, calcular la posició del terminal per mitjà d'un algoritme de tracking o trilateració. El problema clau és que les característiques dels protocols IEEE 802.11 a dia d’avui fan difícil la realització de mesures precises de TOA d’una manera senzilla. El principal repte que afronta el present treball de recerca és demostrar la viabilitat d’això darrer, minimitzant en la major mesura possible les modificacions sobre els equips WLAN comercials. L'objectiu d'aquest treball pot ser entesa com l'exploració dels límits actuals dels mètodes de posicionament basats en TOA sobre WLAN, realitzant contribucions que conformen un mètode complet de localització basat en TOA que pretén anar un pas endavant respecte a les propostes existents. En primer lloc, la investigació sobre ranging basat en TOA -el component clau dels mètode de localització TOA- és explicada en detall. El mètode general adoptat per a calcular el TOA consisteix en la mesura del temps d'anada i tornada del senyal, round trip time (RTT), utilitzant trames MAC IEEE 802.11 per tal de treure el màxim profit de la combinació del protocol IEEE 802.11 i els mecanismes dels dispositius WLAN comercials. Després d'això, es detalla la investigació realitzada sobre trilateració i tracking, la segona etapa dels mètodes de localització basats en TOA. Finalment es descriuen alguns estudis realitzats sobre les prestacions, possibles millores i encaix en futurs estàndars del mètode de localització explorat.

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