1,845 research outputs found
Spatial Identification Methods and Systems for RFID Tags
DisertaÄŤnĂ práce je zaměřena na metody a systĂ©my pro měřenĂ vzdálenosti a lokalizaci RFID tagĹŻ pracujĂcĂch v pásmu UHF. Ăšvod je vÄ›nován popisu souÄŤasnĂ©ho stavu vÄ›deckĂ©ho poznánĂ v oblasti RFID prostorovĂ© identifikace a struÄŤnĂ©mu shrnutĂ problematiky modelovánĂ a návrhu prototypĹŻ tÄ›chto systĂ©mĹŻ. Po specifikaci cĂlĹŻ disertace pokraÄŤuje práce popisem teorie modelovánĂ degenerovanĂ©ho kanálu pro RFID komunikaci. DetailnÄ› jsou rozebrány metody měřenĂ vzdálenosti a odhadu smÄ›ru pĹ™Ăchodu signálu zaloĹľenĂ© na zpracovánĂ fázovĂ© informace. Pro účely lokalizace je navrĹľeno nÄ›kolik scĂ©nářů rozmĂstÄ›nĂ antĂ©n. Modely degenerovanĂ©ho kanálu jsou simulovány v systĂ©mu MATLAB. VĂ˝znamná část tĂ©to práce je vÄ›nována konceptu softwarovÄ› definovanĂ©ho rádia (SDR) a specifikĹŻm jeho adaptace na UHF RFID, která vyuĹľitĂ běžnĂ˝ch SDR systĂ©mĹŻ znaÄŤnÄ› omezujĂ. Diskutována je zejmĂ©na problematika prĹŻniku nosnĂ© vysĂlaÄŤe do pĹ™ijĂmacĂ cesty a poĹľadavky na signál lokálnĂho oscilátoru pouĹľĂvanĂ˝ pro směšovánĂ. Prezentovány jsou tĹ™i vyvinutĂ© prototypy: experimentálnĂ dotazovaÄŤ EXIN-1, měřicĂ systĂ©m zaloĹľenĂ˝ na platformÄ› Ettus USRP a antĂ©nnĂ pĹ™epĂnacĂ matice pro emulaci SIMO systĂ©mu. ZávÄ›reÄŤná část je zaměřena na testovánĂ a zhodnocenĂ popisovanĂ˝ch lokalizaÄŤnĂch technik, zaloĹľenĂ˝ch na měřenĂ komplexnĂ pĹ™enosovĂ© funkce RFID kanálu. Popisuje ĂşzkopásmovĂ©/širokopásmovĂ© měřenĂ vzdálenosti a metody odhadu smÄ›ru signálu. Oba navrĹľenĂ© scĂ©náře rozmĂstÄ›nĂ antĂ©n jsou v závÄ›ru ověřeny lokalizaÄŤnĂm měřenĂm v reálnĂ˝ch podmĂnkách.The doctoral thesis is focused on methods and systems for ranging and localization of RFID tags operating in the UHF band. It begins with a description of the state of the art in the field of RFID positioning with short extension to the area of modeling and prototyping of such systems. After a brief specification of dissertation objectives, the thesis overviews the theory of degenerate channel modeling for RFID communication. Details are given about phase-based ranging and direction of arrival finding methods. Several antenna placement scenarios are proposed for localization purposes. The degenerate channel models are simulated in MATLAB. A significant part of the thesis is devoted to software defined radio (SDR) concept and its adaptation for UHF RFID operation, as it has its specialties which make the usage of standard SDR test equipment very disputable. Transmit carrier leakage into receiver path and requirements on local oscillator signals for mixing are discussed. The development of three experimental prototypes is also presented there: experimental interrogator EXIN-1, measurement system based on Ettus USRP platform, and antenna switching matrix for an emulation of SIMO system. The final part is focused on testing and evaluation of described positioning techniques based on complex backscatter channel transfer function measurement. Both narrowband/wideband ranging and direction of arrival methods are validated. Finally, both proposed antenna placement scenarios are evaluated with real-world measurements.
Research on port AGV composite positioning based on UWB/RFID
In recent years, ports in various countries have successively carried out research and
application of fully automated terminal. The terminal adopts the "Double car shore
bridge + AGV + ARMG" automation process, which is the most widely used and
relatively mature fully automated solution. At present, the AGV navigation of the
terminal is based on RFID magnetic nail positioning and the accuracy is good. However,
nowadays UWB technology has become the most popular technology in ranging and
positioning. The research in this work is based on UWB/RFID composite positioning,
which is mainly used for the specific localization tasks in the port and it can accurately
locate the position of the AGV.
This MSc work studies the UWB positioning system first and then researches the
traditional 3D positioning algorithm. Importance contribution expressed by 3D TOA
localization algorithm. For RFID system, this connection between the reader and the
carrier is designed, and the reference tag is buried. At last, data-based on RFID
localization algorithm in scene analysis method is adopted for positioning. Secondly,
the basis of the composite positioning system is data fusion technology. The most
widely used and mature fusion algorithm is the Kalman filter algorithm and Particle
filter. Finally, the experimental analysis of UWB and RFID composite positioning
system is implemented. The results indicate that UWB and RFID composite positioning
system can reduce the cost of the positioning system. Higher positioning accuracy and
robustness are characterizing the developed system.Nos Ăşltimos anos, portos de vários paĂses realizaram sucessivamente pesquisas e
aplicações de terminais totalmente automatizados. O terminal adota o processo de
automação "Double car shore bridge + AGV + ARMG", que é a solução totalmente
automatizada mais amplamente utilizada e relativamente madura. Atualmente, a
navegação AGV do terminal é baseada no posicionamento da etiqueta RFID e a
precisĂŁo Ă© boa. No entanto, hoje em dia, a tecnologia UWB tornou-se na tecnologia
mais popular relativamente ao alcance e posicionamento. A pesquisa neste trabalho Ă©
baseada no posicionamento composto por UWB / RFID, usado principalmente para
tarefas de localização especĂficas nos portos, podendo desta forma localizar-se com
precisão a posição do AGV.
Este projeto de mestrado estuda em primeiro lugar o sistema de posicionamento UWB,
e depois um algoritmo tradicional de posicionamento 3D. A contribuição da
importância expressa pelo algoritmo de posicionamento “time of arrival” (TOA) 3D foi
proposta. Para o sistema de posicionamento RFID, a conexĂŁo entre o leitor e a
transportadora Ă© projetada e a etiqueta de referĂŞncia Ă© ocultada. Por fim, o algoritmo de
“k-nearest neighbor” baseado numa base de dados e no método de análise de cena é
adotado para realizar o posicionamento. Em segundo lugar, a base do sistema de
posicionamento composto Ă© a tecnologia de fusĂŁo de dados. O algoritmo de fusĂŁo mais
amplamente utilizado e maduro Ă© o algoritmo de filtro Kalman e o filtro de partĂculas.
Finalmente, é realizada a análise experimental do sistema de posicionamento composto
UWB e RFID. Os resultados experimentais mostram que o sistema de posicionamento
composto UWB e RFID pode reduzir o custo do sistema de posicionamento. O sistema
desenvolvido Ă© caracterizado por uma maior precisĂŁo de posicionamento e robustez
Location estimation in smart homes setting with RFID systems
Indoor localisation technologies are a core component of Smart Homes. Many applications within Smart Homes benefit from localisation technologies to determine the locations of things, objects and people. The tremendous characteristics of the Radio Frequency Identification (RFID) systems have become one of the enabler technologies in the Internet of Things (IOT) that connect objects and things wirelessly. RFID is a promising technology in indoor positioning that not only uniquely identifies entities but also locates affixed RFID tags on objects or subjects in stationary and real-time. The rapid advancement in RFID-based systems has sparked the interest of researchers in Smart Homes to employ RFID technologies and potentials to assist with optimising (non-) pervasive healthcare systems in automated homes.
In this research localisation techniques and enabled positioning sensors are investigated. Passive RFID sensors are used to localise passive tags that are affixed to Smart Home objects and track the movement of individuals in stationary and real-time settings. In this study, we develop an affordable passive localisation platform using inexpensive passive RFID sensors. To fillful this aim, a passive localisation framework using minimum tracking resources (RFID sensors) has been designed. A localisation prototype and localisation application that examined the affixed RFID tag on objects to evaluate our proposed locaisation framework was then developed. Localising algorithms were utilised to achieve enhanced accuracy of localising one particular passive tag which that affixed to target objects.
This thesis uses a general enough approach so that it could be applied more widely to other applications in addition to Health Smart Homes. A passive RFID localising framework is designed and developed through systematic procedures. A localising platform is built to test the proposed framework, along with developing a RFID tracking application using Java programming language and further data analysis in MATLAB. This project applies localisation procedures and evaluates them experimentally. The experimental study positively confirms that our proposed localisation framework is capable of enhancing the accuracy of the location of the tracked individual. The low-cost design uses only one passive RFID target tag, one RFID reader and three to four antennas
Wireless Positioning and Tracking for Internet of Things in GPS-denied Environments
Wireless positioning and tracking have long been a critical technology for various applications such as indoor/outdoor navigation, surveillance, tracking of assets and employees, and guided tours, among others. Proliferation of Internet of Things (IoT) devices, the evolution of smart cities, and vulnerabilities of traditional localization technologies to cyber-attacks such as jamming and spoofing of GPS necessitate development of novel radio frequency (RF) localization and tracking technologies that are accurate, energy-efficient, robust, scalable, non-invasive and secure. The main challenges that are considered in this research work are obtaining fundamental limits of localization accuracy using received signal strength (RSS) information with directional antennas, and use of burst and intermittent measurements for localization. In this dissertation, we consider various RSS-based techniques that rely on existing wireless infrastructures to obtain location information of corresponding IoT devices. In the first approach, we present a detailed study on localization accuracy of UHF RF IDentification (RFID) systems considering realistic radiation pattern of directional antennas. Radiation patterns of antennas and antenna arrays may significantly affect RSS in wireless networks. The sensitivity of tag antennas and receiver antennas play a crucial role. In this research, we obtain the fundamental limits of localization accuracy considering radiation patterns and sensitivity of the antennas by deriving Cramer-Rao Lower Bounds (CRLBs) using estimation theory techniques. In the second approach, we consider a millimeter Wave (mmWave) system with linear antenna array using beamforming radiation patterns to localize user equipment in an indoor environment. In the third approach, we introduce a tracking and occupancy monitoring system that uses ambient, bursty, and intermittent WiFi probe requests radiated from mobile devices. Burst and intermittent signals are prominent characteristics of IoT devices; using these features, we propose a tracking technique that uses interacting multiple models (IMM) with Kalman filtering. Finally, we tackle the problem of indoor UAV navigation to a wireless source using its Rayleigh fading RSS measurements. We propose a UAV navigation technique based on Q-learning that is a model-free reinforcement learning technique to tackle the variation in the RSS caused by Rayleigh fading
Diseño y aplicaciones de sistemas de antenas inteligentes para redes inalámbricas en el contexto de la internet de las cosas
[SPA] Esta tesis doctoral se presenta bajo la modalidad de compendio de publicaciones. Las antenas de onda de fuga (LWA) consisten en una estructura de guĂa de onda que permite la fuga de parte de la potencia a lo largo de la estructura. Por esta razĂłn, la radiaciĂłn de la antena se produce por la fuga de energĂa. Para producir una radiaciĂłn coherente, es necesario controlar esta tasa de radiaciĂłn a lo largo de la estructura radiante. AsĂ, ajustando con precisiĂłn la tasa de radiaciĂłn, se controla la forma del diagrama de radiaciĂłn. Las LWAs han sido ampliamente estudiadas por la comunidad cientĂfica debido a sus ventajas, tales como, red de alimentaciĂłn simple, alta directividad y escaneo en frecuencia pasivo. Sin embargo, presentan ciertas desventajas entre las cuales, la más importante a destacar es el efecto de beam-squinting. Éste se produce por la propiedad dispersiva inherente a este tipo de antenas. Además, presentan dificultades a la hora de generar radiaciĂłn coherente en las direcciones broadside y endfire, aumentando la complejidad del diseĹ„o para la radiaciĂłn en dichas direcciones. Las LWA han sido relativamente poco utilizadas en aplicaciones prácticas hasta la fecha, a pesar de sus ventajas. Las pocas aplicaciones en las que se han utilizado son los radares de onda continua modulada en frecuencia y los sistemas de enfoque controlado en frecuencia de campo cercano. Esta tesis propone el uso de las LWAs en aplicaciones prácticas aprovechando las ventajas mencionadas anteriormente y teniendo en cuenta los inconvenientes de este tipo de antenas para que su uso no sea limitado. Recientemente, las LWAs han sido propuestas para aplicaciones de localizaciĂłn de bajo coste, ya que permiten el diseĹ„o de estructuras planas con haces directivos. Además, debido al aumento exponencial del uso de la tecnologĂa, es necesario encontrar nuevas tecnologĂas para una transmisiĂłn de datos mayor, más rápida y más eficiente, manteniendo bajos costes de fabricaciĂłn. Por lo tanto las LWAs pueden ser una soluciĂłn crucial al mezclar bajos costes de fabricaciĂłn, alta integrabilidad en diferentes sistemas debido a su tecnologĂa impresa planar y alta directividad al mismo tiempo que se aprovecha su caracterĂstica dispersiva que proporciona un escaneo pasivo en frecuencia. En este contexto, la principal aportaciĂłn de esta Tesis consiste en el estudio, análisis, diseĹ„o e integraciĂłn de LWAs en aplicaciones reales y prácticas. Esta Tesis presenta las siguientes tres contribuciones principales, definidas en los tres bloques principales de este documento: • Estudio y análisis de LWAs para su uso en sistemas de estimaciĂłn de direcciĂłn de llegada basados en tĂ©cnicas de amplitud de monopulso. Comparar las caracterĂsticas y prestaciones de las LWAs junto con las antenas comerciales más utilizadas. Para ello, diseĹ„ar y fabricar las HWM-LWAs con el fin de comparar sus prestaciones con las antenas de panel adquiridas comercialmente. Dado que cada aplicaciĂłn requiere el diseĹ„o de una HWM-LWA nueva y diferente, estudiar y proponer una tĂ©cnica eficiente de análisis y diseĹ„o de antenas para obtener fácilmente diagramas de radiaciĂłn monopulso escaneados en frecuencia. • Una vez analizado que las HWM-LWA son una soluciĂłn factible para su uso en aplicaciones reales de localizaciĂłn debido a sus diversas ventajas. Integrar las HWM-LWAs diseĹ„adas en sistemas digitales para estimaciĂłn del ángulo de llegada en interiores. Por lo tanto, diseĹ„ar, desarrollar, configurar e integrar las LWAs en diferentes sistemas basados en las bandas de frecuencia Wi-Fi ISM de 2,4 GHz y 5 GHz. Finalmente, comparar los resultados de estimaciĂłn obtenidos con otras soluciones propuestas para corroborar que los LWAs pueden ser utilizados en aplicaciones reales. • Asimismo, debido a su bajo coste de fabricaciĂłn y a su principal propiedad de escaneo en frecuencia. Ampliar el uso de las LWAs para la localizaciĂłn angular en redes de sensores inalámbricas (WSN) utilizando la banda de frecuencias UHF de 900 MHz. Utilizando asĂ etiquetas RFID pasivas. TambiĂ©n estudiar su aplicabilidad en WSNs utilizando etiquetas LoRa activas. Este documento se presenta como una Tesis por compendio, por lo que se presentarán y explicarán brevemente los 4 artĂculos de revistas que se han publicado durante el programa de doctorado. Además, tambiĂ©n se presentarán algunos artĂculos de conferencias y otros trabajos en revisiĂłn para exponer algunas de las investigaciones que no han sido publicadas en revistas hasta la fecha de depĂłsito de tesis. El documento está organizado como se indica a continuaciĂłn: En la IntroducciĂłn, se presenta una contextualizaciĂłn del estado del arte y una explicaciĂłn rigurosa sobre las LWAs y las aplicaciones anteriormente mencionadas. Las dos partes siguientes se vi dedican a presentar y explicar brevemente los trabajos publicados que contribuyen a esta Tesis. En la parte II, se presentan los cuatro artĂculos que conforman el compendio. Esto es, el análisis de las LWAs para la estimaciĂłn de la direcciĂłn del ángulo de llegada y la integraciĂłn de las LWAs en sistemas de localizaciĂłn digital usando el protocolo Wi-Fi en el CapĂtulo 1, la banda de frecuencias ISM UHF 900 MHz se utiliza junto con los HWM-LWAs en el CapĂtulo 2, luego se implementa en un sistema en tiempo real para la estimaciĂłn de la direcciĂłn de llegada de mĂşltiples tags pasivos en el CapĂtulo 3 y la integraciĂłn de LoRa en el CapĂtulo 4. Finalmente, en la Parte III, se discuten las conclusiones generales y las futuras lĂneas de investigaciĂłn. [ENG] This doctoral dissertation has been presented in the form of thesis by publication. Leaky-Wave Antennas (LWA) consist on a waveguide structure which allows the leakage of part of the power along the structure. For this reason, the radiation of the antenna is produced by the leakage of power. In order to produce coherent radiation, it is necessary to control this leakage rate along the radiating structure. Thus, precisely adjusting the leakage rate, the shape of the radiation pattern is controlled. LWAs have been widely studied by the scientific community due to their advantages, such as, simple feeding network, high directivity and passive frequency-scanning performance. However, they present certain disadvantages among which, the most important to highlight is the beam-squinting effect. TThis is due to the inherent dispersion property of this type of antenna. In addition, LWAs present difficulties when generating coherent radiation in broadside and endfire directions, increasing the complexity of the design for radiation in these directions. LWAs have been relatively unused in practical applications to date, despite of their benefits. The few applications in which they have been used are frequency modulated continuous wave radars and near-field frequency controlled focusing systems.This thesis proposes the use of LWAs in practical applications by exploiting the advantages mentioned above while taking into account the drawbacks of this type of antennas so that their use is not limited. Recently, LWAs have been proposed for low-cost localization applications, as they allow the design of planar structures with directive beams. In addition, due to the exponential increase in the use of technology, it is necessary to find new technologies for higher, faster and more efficient data transmission while maintaining low manufacturing costs. Therefore, LWAs can be a crucial solution mixing low manufacturing costs, high integrability in different systems due to their planar printed technology and high directivity while taking advantage of their dispersive characteristic that provides passive frequency scanning. In this context, the main contribution of this Thesis consist of the study, analysis, design and integration of LWAs in real and practical applications. This Thesis presents the following three main contributions, defined in the three main blocks of this document: • Study and analysis of LWAs for its use in direction of arrival estimation systems based on monopulse amplitude techniques. Compare the characteristics and performance of LWAs along with widely used commercial antennas. For this purpose, design and manufacture the HWM-LWAs in order to compare their performance with commercially acquired panel antennas. Since each application requires the design of a new and different HWM-LWA, a main objective of this block is to study and propose an efficient antenna analysis and design technique to facilitate obtaining frequency-scanned monopulse patterns. • Once analyzed that LWAs are a feasible solution for its use in real localization applications due to their several advantages, integrate the designed half-width microstrip (HWM-LWAs) in digital indoor angle-of-arrival estimation systems. Therefore, design, develop, configure and integrate LWAs in different systems based on the Wi-Fi ISM 2.4 GHz and 5 GHz frequency bands. Finally, compare the obtained estimation results with other proposed solutions to corroborate that LWAs can be used in real applications. • Extending the use of antennas for angular localization in sensor networks using the 900 MHz UHF frequency band: the main properties of low manufacturing cost and passive frequency beam scanning can be used in other applications. Thus, the localization estimation of passive RFID tags is studied, as well as their application in Wireless Sensor Networks (WSNs) using active tags with LORA technology. This document is presented as a Thesis by compilation, so the 4 journal articles that have been published during the Ph.D program will be presented and briefly explained. Besides, some conference articles and other work under review will be also presented to expose some of the research that has not been published in journals. The document is organized as outlined hereafter: In Part I, a state-of-the-art contextualization, a rigorous explanation about LWAs and the previous applications mentioned above is presented. The next two parts are dedicated to present and briefly explain the published works included in this Thesis and their main contributions. In Part II the explanation of the four papers which compose the compendium are presented. This is, LWAs analysis for direction of arrival estimation and the integration of LWAs in digital Wi-Fi localization systems in chapter 1, the UHF 900 MHz ISM frequency band is used in conjunction with HWM-LWAs in chapter 2, then, it is implemented in a real time system for direction of arrival estimation of multi RFID tags in chapter 3 and LoRa integration in chapter 4. Finally, in Part III, the overall conclusions and the future research lines are discussed.Esta tesis doctoral se presenta bajo la modalidad de compendio de publicaciones. Está formada por un total de cuatro artĂculos. Article 1.-: A. Gil-Martinez, M. Poveda-Garcia, J. A. Lopez-Pastor, J. C. Sanchez-Aarnoutse and J. L. Gomez-Tornero, Wi-Fi Direction Finding with Frequency-Scanned Antenna and Channel Hopping Scheme IEEE sensors Journal, , vol. 22, no. 6, pp. 5210-5222, 2022. DOI: 10.1109/JSEN.2021.3122232. Article 2.-: A. Gil-Martinez, M. Poveda-Garcia, D. Cañete-Rebenaque, and J. L. Gomez-Tornero, Frequency-Scanned Monopulse Antenna for RSSI-based Direction Finding of UHF RFID tags IEEE Antennas and Wireless Propagation Letters,, vol. 21, no. 1, pp. 158-162, 2022. DOI: 10.1109/LAWP.2021.3122232. Article 3.-: A. Gil-Martinez, M. Poveda-Garcia, J. Garcia-Fernandez, M. Campo-Valera, D. Cañete-Rebenaque, and J. L. Gomez-Tornero, Direction Finding of RFID tags in UHF Band Using a Passive Beam-Scanning Leaky-Wave Antenna IEEE Journal of Radio Frequency Identi cation, doi: 10.1109/JRFID.2021.3122233. Article 4.-: J. L. Gomez-Tornero, A. Gil-Martinez, M. Poveda-Garcia and D. Cañete-Rebenaque, ARIEL: Passive Beam-Scanning Antenna TeRminal for Iridiscent and E cient LEO Satellite Connectivity in IEEE Antennas and Wireless Propagation Letters, doi: 10.1109/LAWP.2022.3193040.Escuela Internacional de Doctorado de la Universidad PolitĂ©cnica de CartagenaUniversidad PolitĂ©cnica de CartagenaPrograma Doctorado en TecnologĂas de la InformaciĂłn y las Comunicacione
ReLoc: Hybrid RSSI- and phase-based relative UHF-RFID tag localization with COTS devices
Radio frequency identification (RFID) technology brings tremendous advancements in the Industrial Internet of Things (IIoT), especially for smart inventory management, as it provides a fast and low-cost way of counting or positioning items in the warehouse. In the last decade, many novel solutions, including absolute and relative positioning methods, have been proposed for this application. However, the available methods are quite sensitive to the minor changes in the deployment scenario, including the orientation of the tag and antenna, the materials contained inside the carton, tag distortion, and multipath propagation. To this end, we propose a hybrid relative passive RFID localization method (ReLoc) based on both the received signal strength indicator (RSSI) and measured phases, which orders the RFID tags horizontally and vertically. In this article, the phase-based variant maximum likelihood estimation is proposed for lateral positioning, and the RSSI profiles of two tilted antennas are compared with each other for level distinguishing. We implement the proposed positioning system ReLoc with commercial off-the-shelf RFID devices. The experiment in a warehouse shows that ReLoc is a powerful solution for practical item-level inventory management. The experimental results show that ReLoc achieves an average lateral and level ordering accuracy of 94.6% and 94.3%, respectively. Notably, when considering liquid or metal materials inside the carton or tag distortion, ReLoc still performs excellently with more than 93% ordering accuracy both horizontally and vertically, indicating the robustness of the proposed method
Dense and long-term monitoring of Earth surface processes with passive RFID -- a review
Billions of Radio-Frequency Identification (RFID) passive tags are produced
yearly to identify goods remotely. New research and business applications are
continuously arising, including recently localization and sensing to monitor
earth surface processes. Indeed, passive tags can cost 10 to 100 times less
than wireless sensors networks and require little maintenance, facilitating
years-long monitoring with ten's to thousands of tags. This study reviews the
existing and potential applications of RFID in geosciences. The most mature
application today is the study of coarse sediment transport in rivers or
coastal environments, using tags placed into pebbles. More recently, tag
localization was used to monitor landslide displacement, with a centimetric
accuracy. Sensing tags were used to detect a displacement threshold on unstable
rocks, to monitor the soil moisture or temperature, and to monitor the snowpack
temperature and snow water equivalent. RFID sensors, available today, could
monitor other parameters, such as the vibration of structures, the tilt of
unstable boulders, the strain of a material, or the salinity of water. Key
challenges for using RFID monitoring more broadly in geosciences include the
use of ground and aerial vehicles to collect data or localize tags, the
increase in reading range and duration, the ability to use tags placed under
ground, snow, water or vegetation, and the optimization of economical and
environmental cost. As a pattern, passive RFID could fill a gap between
wireless sensor networks and manual measurements, to collect data efficiently
over large areas, during several years, at high spatial density and moderate
cost.Comment: Invited paper for Earth Science Reviews. 50 pages without references.
31 figures. 8 table
Localizzazione 2D di tag RFID in banda UHF mediante tecniche ad array sintetico
In questa tesi si sono valutate le prestazioni di un sistema di localizzazione di tag RFID passivi in banda UHF in ambiente indoor. Il sistema, composto da un reader in movimento che percorre una traiettoria nota, ha come obiettivo localizzare il tag attraverso misure di fase; piu precisamente la differenza di fase tra il segnale di interrogazione,emesso dal reader, e il segnale retro-diffuso dal tag
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