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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.
41

Détection et localisation de cibles derrière un mur avec un système radar ULB / Through the wall targets detection and localization with a UWB radar system

Zhao, Xiaowei 16 November 2012 (has links)
Le cadre de cette thèse est centré sur l'étude d'un radar ultra large bande (ULB) en mode impulsionnel, pour la « vision » à travers les murs (VAM), qui présente de nombreuses applications tant dans le domaine militaire (lors des assauts, des prises d’otages, …) que dans le secteur de la sécurité civile (recherche de personnes dans des décombres, dans un incendie, ...). Pour ces utilisations, l’image réelle de la scène observée n’est pas nécessaire, seules certaines informations pertinentes suffisent : nombre de personnes, position, vitesse de déplacement, etc. C'est dans ce contexte que nous avons développé un dispositif expérimental de détection et des techniques de localisation de cibles derrière un mur. Le radar développé est constitué d’un émetteur impulsionnel couvrant la gamme de fréquence de 3 GHz à 6 GHz, et de trois récepteurs indépendants, associés à des algorithmes de localisation et de reconstruction d'image.Le premier algorithme repose sur une technique de trilatération. Une fois, le modèle théorique présenté, plusieurs méthodes de résolution sont étudiées pour l'estimation de la mesure de la distance de propagation du signal. La méthode de Brent-Dekker a été retenue pour sa rapidité de convergence et son faible nombre d’itérations. Bien que cette technique soit précise, elle ne permet pas d’obtenir une image de la scène, mais juste de localiser les cibles, sans apporter des informations sur ses dimensions. C’est pourquoi une seconde approche, basée sur une « formation de faisceau », a été étudiée, afin d'obtenir une représentation 2D de la scène. Nous avons choisi de développer une méthode de rétroprojection non cohérente, technique la plus simple qui ne nécessite pas de contrainte forte sur la phase du signal ni sur le positionnement des antennes. Différentes variantes de rétroprojection ont été proposées : la rétroprojection avec cross corrélation, la rétroprojection cross corrélation améliorée et la rétroprojection bicross corrélée. Ces trois méthodes reposent sur une fusion d'informations capturées par l'antenne réceptrice avec celles obtenues sur des antennes dites de référence. Cette fusion a permis d'améliorer progressivement le rendu des images.Pour conclure ses travaux, une perspective est ébauchée afin de minimiser le taux de fausse détection, elle s'appuie sur la collaboration de la technique de trilatération avec la technique de rétroprojection bicross corrélée. Cette collaboration permet de mettre en correspondance les détections estimées par la technique de trilatération et celles utilisant la rétroprojection bicross corrélée. Les cibles non appariées sont alors supprimées selon des critères spécifiques à chacune des deux approches. / The content of this thesis is focused on the study of an UWB pulse radar for through the wall vision which has many applications in the military domain (assaults, hostage rescue,…) and in the civil security domain (people search in the rubble, in a fire).For these uses, the real observed scene image is not necessary, only some relevant information is enough: number of persons, position, velocity of movement, etc. It’s in this context where we have developed an experimental detection device and some through the wall targets localization techniques. The developed radar consists of a pulse transmitter covering the frequency range from 3GHz to 6GHz, and three independent receivers, combined with some localization algorithms and image reconstruction.The first algorithm is based on a technique of trilateration. Once the theoretical model is presented, many resolutions methods are studied for estimation of the signal propagation distance measurement. The Brent-Dekker method has been chosen for its fast convergence and low number of iterations. Although the trilateration technique is accurate, it does not allow obtaining a scene image, but just locate the targets, without providing their dimensions. Therefore a second approach, based on a “beam forming”, has been studied, in order to obtain a 2D scene representation. We have chosen to develop a non-coherent backprojection method, it is the most simple technique which does not require a strong constraint on the signal phase nor on the antenna positions. Different backprojection methods have been proposed: the backprojection with cross correlation, the improved backprojection with cross correlation and bi-cross correlated backprojection. These three methods are based on a fusion of captured information by the receiving antennas and with the obtained information on the “referenced” antennas. This fusion allows improving the image quality progressively.To conclude this work, a perspective is initiated in order to minimize the false detection rate, it is based on the cooperation of the trilateration technique and bi-cross correlated backprojection. This cooperation allows matching the estimated detection by the trilateration technique and the bi-cross correlated backprojection technique. The mismatched targets are removed according to some specific criterias to each approach.
42

Mobile Electronic Dispensary System

Stokes, Nancy Elizabeth 23 April 2013 (has links)
The Mobile Electronic Dispensary System (MEDS) is an indoor medical dispensary system where robots locate and travel to patients within a grid in order to deliver medication or other medical supplies based on a predefined schedule. For older people or individuals with physical or mental disabilities, it is important to ensure that medications are taken as prescribed. Missing or mixing dosages can cause unwanted and even harmful consequences. As individuals grow older or battle disabilities, it is expected that adhering to their medicine regimen will be a daily challenge without the assistance of a fulltime caregiver. Therefore, to assist individuals in maintaining their independence, MEDS ensures the proper medicine is dispensed to the patient at the prescribed time and dosage. At the core of MEDS is a scheduler that maintains the medicines to be dispensed, including the times and dosages. Once a scheduled time arrives to deliver medicine to a patient, MEDS instructs the appropriate robot to wake up, locate the patient within a defined grid, and then travel to the patient and deliver the medicine. Upon receiving the delivery, the patient will accept the medicine physically and then update their mobile device, informing MEDS that the medicine was successfully delivered. At this time, the robot will return to its home base within the grid. The patients are within the confines of a building where GPS is not a viable solution to track items to pinpoint accuracy. Therefore, an indoor location based system with beacons and listeners are required in order to define a grid and enable robots to locate and travel to the patient. This paper defines and details the programs, database, algorithms, and hardware of MEDS using the Cricket Indoor Location System and iRobot Creates. / text
43

Synthetic Aperture Sonar Micronavigation Using An Active Acoustic Beacon.

Pilbrow, Edward Neil January 2007 (has links)
Synthetic aperture sonar (SAS) technology has rapidly progressed over the past few years with a number of commercial systems emerging. Such systems are typically based on an autonomous underwater vehicle platform containing multiple along-track receivers and an integrated inertial navigation system (INS) with Doppler velocity log aiding. While producing excellent images, blurring due to INS integration errors and medium fluctuations continues to limit long range, long run, image quality. This is particularly relevant in mine hunting, the main application for SAS, where it is critical to survey the greatest possible area in the shortest possible time, regardless of sea conditions. This thesis presents the simulation, design, construction, and sea trial results for a prototype "active beacon" and remote controller unit, to investigate the potential of such a device for estimating SAS platform motion and medium fluctuations. The beacon is deployed by hand in the area of interest and acts as an active point source with real-time data uploading and control performed by radio link. Operation is tightly integrated with the operation of the Acoustics Research Group KiwiSAS towed SAS, producing one-way and two-way time of flight (TOF) data for every ping by detecting the sonar chirps, time-stamping their arrival using a GPS receiver, and replying back at a different acoustic frequency after a fixed time delay. The high SNR of this reply signal, combined with the knowledge that it is produced by a single point source, provides advantages over passive point-like targets for SAS image processing. Stationary accuracies of < 2 mm RMS have been measured at ranges of up to 36m. This high accuracy allowed the beacon to be used in a separate study to characterise the medium fluctuation statistics in Lyttelton Harbour, New Zealand, using an indoor dive pool as a control. Probability density functions were fitted to the data then incorporated in SAS simulations to observe their effect on image quality. Results from recent sea trials in Lyttelton Harbour show the beacon TOF data, when used in a narrowband motion compensation (MOCOMP) process, provided improvements to the quality of SAS images centred on frequencies of 30 kHz and 100 kHz. This prototype uses simple matched-filtering algorithms for detection and while performing well under stationary conditions, the fluctuations caused by the narrow sonar transmit beam pattern (BP) and changing superposition of seabed multipath often cause dropouts and inaccurate detections during sea trials. An analysis of the BP effects and how the accuracy and robustness of the detection algorithms can be improved is presented. Overcoming these problems reliably is difficult without dedicated large scale testing facilities to allow conditions to be reproduced consistently.
44

Comparison and implementation of IPS

Helgesson, Dan, Nilsson, Emelie January 2014 (has links)
Innomhuspositioneringssystem kan med fördel användas i många olika tillämpningar, allt från sjukhus till shoppingcenter. Denna rapport behandlar olika tekniker och lösningar för att designa ett positioneringssystem. Rapporten tar även upp i detalj hur ett system kan konstrueras av ZigBee kombinerat med dödräkning.
45

Radio frequency ranging for precise indoor localization

Sark, Vladica 15 February 2018 (has links)
In den letzten Jahrzehnten sind Satellitennavigationssysteme zu einem unverzichtbaren Teil des modernen Lebens geworden. Viele innovative Anwendungen bieten ortsabhängige Dienste an, welche auf diesen Navigationssystemen aufbauen. Allerdings sind diese Dienste in Innenräumen nicht verfügbar. Daher werden seit einigen Jahren alternative Lokalisierungsmethoden für Innenräume aktiv erforscht und entwickelt. Der Schwerpunkt dieser Arbeit liegt darauf, die Genauigkeit von Lokalisationsmethoden in Innenräumen zu erhöhen, sowie auf der effektiven Integration der entsprechenden Verfahren in drahtlose Kommunikationssysteme. Es werden zwei Ansätze vorgeschlagen und untersucht, welche die Präzision von ToF-basierten Methoden erhöhen. Zum einen wird im „Modified Equivalent Time Sampling“ (METS) Verfahren eine überabgetastete Version der vom Radioempfänger gelieferten Wellenform erzeugt und zur ToF Bestimmung verwendet. Der zweite erforschte Ansatz hat zum Ziel, Fehler auf Grund von Taktfrequenz-Abweichungen zu kompensieren. Dieses ist für kooperative Lokalisationsmethoden (N-Way ranging) von Bedeutung. Das in der Arbeit entwickelte Verfahren führt zu einer erheblichen Reduzierung der Fehler in der Abstandsmessung und damit der Positionsbestimmung. Darüber hinaus wurde eine neue Methode untersucht, um Lokalisationsverfahren in Funksysteme für die ISM Bänder bei 2,4 GHz und 5 GHz zu integrieren. Die Methode wurde auf einer Software Defined Radio (SDR) Plattform implementiert und bewertet. Es konnte eine Genauigkeit bis zu einem Meter in der Positionsbestimmung demonstriert werden. Schließlich wurde ein Verfahren vorgeschlagen und untersucht, mit welchem Lokalisationsfähigkeit in bestehende Funksysteme integriert werden kann. Die betrachtete Methode wurde in einem 60 GHz Funksystem mit hoher Datenrate implementiert. Die Untersuchungen zeigten eine Positionsgenauigkeit von 1 cm bei einer gleichzeitig hohen Datenrate für die Übertragung von Nutzdaten. / In the last couple of decades the Global Navigation Satellite Systems (GNSS) have become a very important part of our everyday life. A huge number of applications offer location based services and navigation functions which rely on these systems. Nevertheless, the offered localization services are not available indoors and their performance is significantly affected in urban areas. Therefore, in the recent years, a large number of wireless indoor localization systems are being actively investigated and developed. The main focus of this work is on improving precision and accuracy of indoor localization systems, as well as on the implementation and integration of localization functionality in wireless data transmission systems. Two approaches for improving the localization precision and accuracy of ToF based methods are proposed. The first approach, referred to as modified equivalent time sampling (METS) is used to reconstruct an oversampled versions of the waveforms acquired at the radio receiver and used for ToF based localization. The second proposed approach is used to compensate the ranging error due to clock frequency offset in cooperative localization schemes like N-Way ranging. This approach significantly reduces the ranging and, therefore, localization errors and has much better performance compared to the existing solutions. An approach for implementation of localization system in the 2.4/5 GHz ISM band is further proposed in this work. This approach is implemented and tested on a software defined radio platform. A ranging precision of better than one meter is demonstrated. Finally, an approach for integrating localization functionality into an arbitrary wireless data transmission system is proposed. This approach is implemented in a 60 GHz wireless system. A ranging precision of one centimeter is demonstrated.
46

Indoor localization of hand-held Shopping Scanners / Inomhuslokalisering med handhållen terminal för detaljhandeln

Persson, Lucas, Markström, Sebastian January 2017 (has links)
This thesis investigates applicable indoor navigation systems for the next generation of hand-held shopping scanners, on behalf of the company Virtual Stores. The thesis research and review applicable indoor localization methods and ways to combine and evaluate received localization data in order to provide accurate navigation without introducing any other worn equipment for a potential user. Prototype navigation systems was proposed, developed and evaluated using a combination of carefully placed radio transmitters that was used to provide radio based localization methods using Bluetooth or UltraWide Band (UWB) and inertial sensors combined with a particle filter. The Bluetooth solution was deemed incapable of providing any accurate localization method while the prototype using a combination of UWB and inertial sensors proved promising solution with below 1m average error under optimal conditions or 2.0m average localization error in a more realistic environment. However, the system requires the surveyed area to provide 3 or more UWB transmitters in the line of sight of the UWB receiver of the user at every location facing any direction to provide accurate localization. The prototype also requires to be scaled up to provide localization to more than 1 radio transmitters at the time before being introduced to the Fast moving consumer goods market. / Denna avhandling undersöker tillämpliga inomhusnavigationssystem för nästa generations handhållna shopping terminaler, på uppdrag av företaget Virtual Stores. Avhandlingen undersöker och granskar tillämpliga inomhuslokaliseringsmetoder och sätt att kombinera och utvärdera mottagna lokaliseringsdata för att bistå med ackurat navigering utan att introducera någon ytterligare utrustning för en potentiell användare. Prototypnavigationssystem föreslogs, utvecklades och utvärderades användandes en kombination av väl utplacerade radiosändare användandes Bluetooth eller UltraWide Band (UWB) och tröghetssensorer i kombination med ett partikelfilter. Bluetooth-lösningen ansågs oförmögen att tillhandahålla någon exakt lokalisering medan prototypen som använde en kombination av UWB och tröghetssensorer visade sig vara en lovande lösnings med under 1m genomsnittligt fel under optimala förhållanden eller 2,0m genomsnittligt lokaliseringsfel i mer realistisk miljö. Systemet kräver emellertid att det undersökta området tillhandahåller 3 eller fler UWB-sändare inom synfältet för UWB-mottagaren hos användaren vid varje plats och riktning för att tillhandahålla ackurat lokalisering. Prototypen behöver skalas upp för att kunna bistå med lokalisering till mer än 1 radiomottagare innan den introduceras till detaljhandlen.
47

A secure localization framework of RAIN RFID objects for ambient assisted living / Un système sécurisé de localisation d’objets RAIN RFID pour l’assistance et l'autonomie des personnes à domicile

Khalid, Ahmad 13 November 2017 (has links)
Internet des objets (IoT) est actuellement à notre portée. De nombreux domaines ont bénéficié de cette technologie. Cela va d'une application simple, comme l'identification d'un objet jusqu'à la gestion d'un système plus complexe. L'identification par radiofréquence (RFID) est l'une des technologies a une part importante dans l’IoT aujourd'hui. C’est une technologie embarqué, pas cher et ne nécessite aucune source d'alimentation supplémentaire dans le cas de tag passif. Avec sa fonctionnalité omniprésente, cette technologie permet de positionner un objet dans une zone spécifique. L’Assistance et l'Autonomie des personnes à Domicile (AAL) est l'un des nombreux domaines qui bénéficient de l'IoT. Il vise à aider les personnes âgées dans leurs routines quotidiennes en fournissant de nouveaux services d'assistance dans les maisons intelligentes (smart home). La présence de RFID dans une maison intelligente sont d'une grande aide pour une personne âgée et/ou déficiente, par exemple, pour l’aider à trouver un objet dans son environnement quotidien. Cependant, même avec tous ces avantages d’assistance dans notre vie, il est malheureusement à double tranchant où l'avantage qu'il apporte à un objet pourrait à son tour se tourner contre lui-même. En effet, pour pouvoir aider les personnes âgées à localiser un objet, le système nécessite certaines données relatives au positionnement de l'objet, tout au moins son identification. Étant donné que la couverture de l'étiquette RFID passive est très faible, une fois sa présence détectée, il est difficile de la cacher. La capacité de cette technologie à localiser des objets donne l'occasion à une tierce personne de profiter du système. Parallèlement au besoin persistant et constant de confidentialité par les utilisateurs, l'objectif de cette thèse consiste à améliorer la confidentialité dans la localisation d'un objet grâce à un nouveau protocole basé sur la deuxième génération de RFID passive. Le protocole proposé doit pouvoir empêcher un objet d'être identifié et localisé par des parties non autorisées ou par un lecteur malveillant. La première contribution de ce travail est l'évaluation de la gestion anti-collision RFID. Elle est réalisée par la création d'un modèle OMNET++, construit sur la base de la dernière norme RFID développée par GS1 et adaptée par ISO / IEC appelé Gen2V2 (RFID classe 2 Génération 2 Version 2). Dans cette norme une étiquette RFID passive ne nécessite aucune source d'alimentation interne. Il communique en utilisant la fréquence UHF. La norme Gen2V2 propose une liste de suites cryptographiques qui peuvent être utilisées comme méthodes pour authentifier une étiquette et un lecteur. Cette nouvelle génération d'étiquettes est soutenue par une alliance de fabricants appelée RAIN (RAdio frequency IdentifatioN) qui favorise l'adoption du Gen2V2. Nous évaluons les performances globales du protocole anti-collision et nous comparons ensuite quatre de ses suites cryptographiques, à savoir PRESENT80, XOR, AES128 et cryptoGPS pour garantir l’authentification lecteur/tag. Parmi les performances évaluées dans ce modèle, nous nous sommes intéressé au nombre de collisions et à la durée requise pour interroger un groupe d'étiquettes. Nous avons intégré en fonctionnalité de localisation dans le modèle en s’appuyant sur les messages échangés avant l’authentification, ce qui peut conduire à une localisation malveillante d'un objet. Pour augmenter la confidentialité de la localisation au sein des applications AAL, nous proposons donc une deuxième contribution qui est une nouvelle méthode de localisation basée sur les échanges standard Gen2V2 en anonymisant l'identité de l'étiquette. / Internet of things (IoT) is currently on our doorsteps. Numerous domains have beneted from this technology. It ranges from a simple application such as identifying an object up to handling a more complex system. The Radio Frequency IDentication (RFID) is one of the enabling technologies that drive the IoT to its position today. It is small, cheap and does not require any additional power sources. Along with its ubiquitous functionality, this technology enables the positioning of an object within a specic area. Ambient Assisted Living (AAL) is one of the many domains that benet from the IoT. It aims at assisting elderly people in their daily routines by providing new assistive services in smart homes for instance. RFIDs in a smart home come as a great help to an elderly person, for example, to nd an object that they misplaced. However, even with all its benets in simplifying our lives, it is unfortunately double-edged where the advantage that it brings to an object could in turn go against itself. Indeed to be able to help the older adults to locate an object, the system requires certain data in relation to the positioning of the object and its identication. As the passive RFID tag coverage is very small, once its presence is detected, it is dicult to hide it. The ability of this technology in localizing objects gives an opportunity to a third person to take an advantage of the system. In parallel with the persistent and constant need of privacy and secrecy by the users, the objective of this thesis consists of improving the privacy in localizing an object through a new protocol based on the latest version of the RFID second generation passive tag. The proposed protocol must be able to prevent an object from being identied and located by unauthorized parties or a malicious reader. The rst contribution of this work is the assessment of the RFID anti collision management. It is performed through the creation of an OMNET++ framework, modelled and built based on the latest RFID standard developed by GS1 and incorporated by ISO/IEC called Gen2V2 (RFID class 2 Generation 2 Version 2). It is a passive RFID tag that does not require any internal power sources to operate. It communicates using the UHF frequency. The Gen2V2 standard provides a list of cryptographical suites that can be used as a method to authenticate a tag and a reader. This new generation of tags is supported by an alliance of manufacturers called RAIN (RAdio frequency IdenticatioN) that promotes the adoption of the Gen2V2. The anti collision management overall performance is then compared with its theoretical value and four of its cryptographical suites namely PRESENT80, XOR, AES128 and cryptoGPS. Among the performances evaluated within the framework is the number of collisions and the duration required to interrogate a group of tags. Note that an addition of a localization functionality within the framework reveals that exchanged messages through wireless channel prior to the authentication can lead to a malicious localization of an object. To increase the localization privacy within AAL application, we propose therefore a second contribution which is a new localization method that is based on the current Gen2V2 standard exchanges by anonymizing the tag identity.
48

Desvendando a matemática do GPS

Lima, Davi Dantas 12 April 2013 (has links)
The purpose of this monograph is to study the mathematical principles behind the Global Positioning System, the so-called GPS. We start with a historical approach of the evolution of this technology. Then we show some theorems in geometry: plane, spatial and analytic, which together with some physical principles (average speed, speed of light, the Doppler effect,...) guided the creators of this powerful tool that determines with remarkable accuracy the position (latitude, longitude and altitude) of a transmitter. Finally, we suggest activities to be performed at the level of basic education, to stimulate students curiosity by scientific knowledge contained therein. / A presente monografia tem como objetivo evidenciar os princípios matemáticos por trás do funcionamento do Sistema de Posicionamento Global conhecido por GPS. Após uma abordagem geral da evolução ocorrida até chegarmos a essa tecnologia, demonstraremos alguns teoremas das geometrias: plana, espacial e analítica que, aplicados juntamente com alguns princípios da Física (velocidade média, velocidade da luz, efeito Doppler,...), nortearam os criadores desta poderosa ferramenta que determina com notáveis precisão e exatidão, em qualquer parte do globo terrestre incluindo a atmosfera, a hora e a posição (latitude, longitude e altitude) de um transmissor. E, a partir daí, sugerir atividades interdisciplinares, a serem desenvolvidas em nível de educação básica, que estimulem a curiosidade dos alunos pelos conhecimentos científicos nelas contidos.
49

RFID Emergency System for Tumble Detection of Solitary People

Ge, Quanyi, Chai, Yi January 2012 (has links)
RFID (Radio Frequency Identification) system is a wireless system without any kinds of mechanical or optical connection between identifying and detected objects. It consists of two basic devices: a reader and tag. Recently with the development of the technology, SAW-RFID (Surface Acoustic Wave Radio Frequency Identification) tags come into market with acceptable price, as well as its size tends to miniaturization. We propose to use 3D wireless indoor localization system to detect the position of the tags. The reader converts radio waves returned from the SAW-RFID tag into a form, which can be useful to process the information. The system consists of SAW-RFID tags placed on the object and several RF Readers in the room. The readers sequentially transmit the impulse signals which are then reflected from different tags and received by readers. Then a signal round-trip TOA (Time of Arrival) between tags and readers can be estimated. We define a 3D coordinate system of the readers and calculate the positions of the tags using suitable specific algorithm. Our system is design to monitor a human body position. The goal is to detect a tumble of solitary living people. A case when the tag positions are identified to be below a per-set threshold means that something happened, and maybe a man has fallen on the ground. This emergency situation can be detected by the monitoring system which then sends information to an alarm system which can call the health centre to take care of the patient. In this paper, a 5 m×5 m×3 m indoor localization system is implemented in Matlab. The simulation results show a correct identification of a fallen man and accuracy of the high measurement below 30 cm. / 0762770008
50

Detekce přítomnosti osob pomocí IoT senzorů / Room Occupancy Detection with IoT Sensors

Kolarčík, Tomáš January 2021 (has links)
The aim of this work was to create a module for home automation tools Home Assistant. The module is able to determine  which room is inhabited and estimate more accurate position of people inside the room. Known GPS location cannot be used for this purpose because it is inaccurate inside buildings and therefore one of the indoor location techniques needs to be used. Solution based on Bluetooth Low Energy wireless technology was chosen. The localization technique is the fingerprinting method, which is based on estimating the position according to the signal strength at any point in space, which are compared with a database of these points using machine learning. The system can be supplemented with motion sensors that ensure a quick response when entering the room. This system can be deployed within a house, apartment or small to medium-sized company to determine the position of people in the building and can serve as a very powerful element of home automation.

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