149 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.
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Performance Analysis of Passive UHF RFID Systems under Cascaded Fading Channels and Interference Effects
In this paper, the performance of monostatic and
bistatic passive ultrahigh-frequency radio-frequency identification
(UHF RFID) systems under the effects of cascaded fading
channels and interference is studied. The performance metric
used is tag detection probability defined as probability that the
instantaneous received power is higher than the receiver’s sensitivity.
A closed-form expression of the detection probability is
derived using cascaded forward and backscatter fading channels
and reader antennas orientation. Furthermore, the performance
of passive RFID systems under reader-to-tag interference caused
by both the desired RFID signal and multiple RFID interferers
is analyzed, and the effect of constructive and destructive
interferences is examined. In addition, the maximum reading
range in ideal, multipath fading and interfering environments is
presented. The obtained results are very useful for the design and
optimization of passive RFID systems from RF point of view.This work was made possible by NPRP grant NPRP4-726-2-272 from
the Qatar National Research Fund (a member of Qatar Foundation).This is the accepted manuscript. The final version is available from IEEE at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumber=6942226
Theoretical Findings and Measurements on Planning a UHF RFID System inside a Room
This paper investigates the problem of improving the identification performance of a UHF RFID system inside a room. We assume static reader, passive tags and availability of commodity antennas. A ray-tracing propagation model is developed that includes multipath in 3D space. It is found that careful selection of reader antenna placement and tilting must be performed to control destructive interference effects. Furthermore, 3D coverage performance gains on the order of 10% are observed by implementing tags’ diversity. A device that successfully manipulates destructive interference is introduced. All theoretical findings are verified by measurements. Finally, a method to perform propagation measurements with commodity RFID hardware is demonstrated
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
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
Digital Beamforming Techniques for Passive UHF RFID Tag Localization
Radio-frequency identification (RFID) technology is on the way to substitute traditional
bar codes in many fields of application. Especially the availability of passive ultra-high
frequency (UHF) RFID transponders (or tags) in the frequency band between 860 MHz
and 960 MHz has fostered the global application in supply chain management. However,
the full potential of these systems will only be exploited if the identification of objects
is complemented by accurate and robust localization.
Passive UHF RFID tags are cost-effective, very small, extremely lightweight, maintenancefree,
rugged and can be produced as adhesive labels that can be attached to almost any
object. Worldwide standards and frequency regulations have been established and a
wide infrastructure of identification systems is operated today. However, the passive
nature of the technology requires a simple communication protocol which results in
two major limitations with respect to its use for localization purposes: the small signal
bandwidth and the small allocated frequency bandwidth. In the presence of multipath
reflections, these limitations reduce the achievable localization accuracy and reliability.
Thus, new methods have to be found to realize passive UHF RFID localization systems
which provide sufficient performance in typical multipath situations.
In this thesis, an enhanced transmission channel model for passive UHF RFID localization
systems has been proposed which allows an accurate estimation of the channel
behaviour to multipath. It has been used to design a novel simulation environment and
to identify three solutions to minimize multipath interference: a) by varying the channel
interface parameters, b) by applying diversity techniques, c) by installation of UHF
absorbers. Based on the enhanced channel model, a new method for tag readability
prediction with high reliability has been introduced. Furthermore, a novel way to rate
the magnitude of multipath interference has been proposed. A digital receiver beamforming
localization method has been presented which uses the Root MUSIC algorithm
for angulation of a target tag and multipath reducing techniques for an optimum localization
performance. A new multiangulation algorithm has been proposed to enable
the application of diversity techniques. A novel transmitter beamforming localization
approach has been presented which exploits the precisely defined response threshold
of passive tags in order to achieve high robustness against multipath. The basic technique
has been improved significantly with respect to angular accuracy and processing
times. Novel experimental testbeds for receiver and transmitter beamforming have been
designed, built and used for verification of the localization performance in real-world
measurements. All the improvements achieved contribute to an enhancement of the accuracy and especially
the robustness of passive UHF RFID localization systems in multipath environments
which is the main focus of this researc
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The Design and Implementation of a Mobile RFID Tag Sorting Robot
Libraries, manufacturing lines, and offices of the future all stand to benefit from knowing the exact spatial order of RFID-tagged books, components, and folders, respectively. To this end, radio- based localization has demonstrated the potential for high accuracy. Key enabling ideas include motion-based synthetic aperture radar, multipath detection, and the use of different frequencies (channels). But indoors in real-world situations, current systems often fall short of the mark, mainly because of the prevalence and strength of "multipath" reflections of the radio signal off nearby objects. In this paper we describe the design and implementation of MobiTagbot, an autonomous wheeled robot reader that conducts a roving survey of the above such areas to achieve an exact spatial order of RFID- tagged objects in very close (1–6 cm) spacings. Our approach leverages a serendipitous correlation between the changes in multipath reflections that occur with motion and the effect of changing the carrier frequency (channel) of the RFID query. By carefully observing the relationship between channel and phase, MobiTagbot detects if multipath is likely prevalent at a given robot reader location. If so, MobiTagbot excludes phase readings from that reader lo- cation, and generates a final location estimate using phase readings from other locations as the robot reader moves in space. Experimentally, we demonstrate that cutting-edge localization algorithms including Tagoram are not accurate enough to exactly order items in very close proximity, but MobiTagbot is, achieving nearly 100% ordering accuracy for items at low (3–6 cm) spacings and 86% accuracy for items at very low (1–3 cm) spacings
A phase-based technique for localization of uhf-rfid tags moving on a conveyor belt: Performance analysis and test-case measurements
A new phase-based technique for localization and
tracking of items moving along a conveyor belt and equipped with
ultrahigh frequency-radio frequency identification (UHF-RFID)
tags is described and validated here. The technique is based on
a synthetic-array approach that takes advantage of the fact that
the tagged items move along a conveyor belt whose speed and
path are known apriori. In this framework, a joint use is done
of synthetic-array radar principles, knowledge-based processing,
and efficient exploitation of the reader-tag communication signal.
The technique can be easily implemented in any conventional
reader based on an in-phase and quadrature receiver and it does
not require any modification of the reader antenna configurations
usually adopted in UHF-RFID portals. Numerical results are used
to investigate the performance analysis of such methods, and
also to furnish system design guidelines. Finally, the localization
capability is also demonstrated through a measurement campaign
in a real conveyor belt scenario, showing that a centimeter-order
accuracy in the tag position estimation can be achieved even in
a rich multipath environment
Sulautettu ohjelmistototeutus reaaliaikaiseen paikannusjärjestelmään
Asset tracking often necessitates wireless, radio-frequency identification (RFID). In practice, situations often arise where plain inventory operations are not sufficient, and methods to estimate movement trajectory are needed for making reliable observations, classification and report generation.
In this thesis, an embedded software application for an industrial, resource-constrained off-the-shelf RFID reader device in the UHF frequency range is designed and implemented. The software is used to configure the reader and its air-interface operations, accumulate read reports and generate events to be reported over network connections. Integrating location estimation methods to the application facilitates the possibility to make deploying middleware RFID solutions more streamlined and robust while reducing network bandwidth requirements.
The result of this thesis is a functional embedded software application running on top of an embedded Linux distribution on an ARM processor. The reader software is used commercially in industrial and logistics applications. Non-linear state estimation features are applied, and their performance is evaluated in empirical experiments.Tavaroiden seuranta edellyttää usein langatonta radiotaajuustunnistustekniikkaa (RFID). Käytännön sovelluksissa tulee monesti tilanteita joissa pelkkä inventointi ei riitä, vaan tarvitaan menetelmiä liikeradan estimointiin luotettavien havaintojen ja luokittelun tekemiseksi sekä raporttien generoimiseksi.
Tässä työssä on suunniteltu ja toteutettu sulautettu ohjelmistosovellus teolliseen, resursseiltaan rajoitettuun ja kaupallisesti saatavaan UHF-taajuusalueen RFID-lukijalaitteeseen. Ohjelmistoa käytetään lukijalaitteen ja sen ilmarajapinnan toimintojen konfigurointiin, lukutapahtumien keräämiseen ja raporttien lähettämiseen verkkoyhteyksiä pitkin. Paikkatiedon estimointimenetelmien integroiminen ohjelmistoon mahdollistaa välitason RFID-sovellusten toteuttamisen aiempaa suoraviivaisemin ja luotettavammin, vähentäen samalla vaatimuksia tietoverkon kaistanleveydelle.
Työn tuloksena on toimiva sulautettu ohjelmistosovellus, jota ajetaan sulautetussa Linux-käyttöjärjestelmässä ARM-arkkitehtuurilla. Lukijaohjelmistoa käytetään kaupallisesti teollisuuden ja logistiikan sovelluskohteissa. Epälineaarisia estimointiominaisuuksia hyödynnetään, ja niiden toimivuutta arvioidaan empiirisin kokein
A Long-range Fine-scale RF Positioning System Using Tunneling Tags
Fine-scale positioning systems using inexpensive, low-power, and reliable smart tags enables numerous commercial and scientific applications. Internet of Things (IoT) applications, such as asset tracking, contact tracing, and autonomous driving, require wireless technologies with both the long ranges of conventional wireless links and the low power consumption of passive and semi-passive Radio Frequency Identification (RFID) tags. This dissertation proves that using the Received Signal Phase (RSP)-based positioning method and Tunneling tags at 5.8 GHz breaks the range limit of fine-scale RFID positioning systems. A frequency hopping reader operating in the 5.8 GHz Industrial, Scientific and Medical (ISM) band is designed and implemented in this work. Experimental results yield a one-dimensional distance estimation error of less than 1% at ranges of 100 m when a clear Line-of-Sight (LoS) is available in indoor and outdoor environments. Compared to Received Signal Strength (RSS)-based positioning techniques, the average positioning accuracy is improved by a factor of 51 at ranges of tens of meters. In Non-Line-of-Sight (NLoS) scenarios, the proposed system achieves an estimation error of less than 1.9%. Experimental results also demonstrate that the RSP-based positioning technique allows estimating a mobile reader's two-dimensional position with an average error of 0.17 m in an outdoor environment. Also, a channel sounder implementation using the same hardware configuration further increases the accuracy in multipath environments. Calculation based on the system specifications projects a sub-meter level accuracy at ranges of more than 1 km is feasible using the proposed method.Ph.D
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