System Development for Geolocation in Harsh Environments

Wireless sensor networks (WSN) consist of a set of distributed devices equipped with multiple sensors, which can be employed in different environments of varying characteristics. Nowadays, node localization has become one of their most basic and important requirements. Due to the nature of certain environments, typical positioning systems, such as Global Navigation Satellite System (GNSS), cannot be employed. Therefore, in recent years several alternative positioning mechanisms have risen. ROMOVI is a project which has as its main goal the development of low cost autonomous robots capable of monitoring and perform logistic tasks on the steep slopes of the Douro river vineyards. Integrated in this project, this dissertation proposes the development of a full-custom wireless communication system for geolocation purposes in harsh environments. Using a Symmetric Double Sided Two Way Ranging (SDS-TWR) algorithm, it is possible to achieve ranging measures between nodes, thus providing accurate relative positioning. This work focuses mainly on the study of the SDS-TWR algorithm and its major error sources, such as those due to digital clock drift, among others. A preamble based on Frank-Zadoff-Chu sequence was developed and, due to its good periodic autocorrelation properties, a system employing the transmission and reception of this preamble was implemented in hardware, through a field programmable gate array (FPGA). By employing an embedded logic processor, the Altera Nios II, control over the complete procedure of the aforementioned algorithm is possible, to perform and analyze the main advantages of the SDS-TWR algorithm. Finally, a medium access control (MAC) layer frame format was defined, in order to enable future development of communication among multiple nodes, to enhance the original algorithm and, as such, provide the capability of trilateration

A Real Time Locating System based on TDOA estimation of UWB pulse sequences

L'abstract è presente nell'allegato / the abstract is in the attachmen

Wireless Technologies for Indoor Asset Positioning

The Positioning of assets in a manufacturing industry is one of the milestones in the process to increase the visibility inside the factory and improve the current manufacturing practices. Furthermore, in order to cope with the high mobility of the assets in a factory, the utilization of wireless technologies has been increased in the past few years in order to develop the positioning applications. However, the utilization of these technologies must not increase the complexity of the manufacturing systems. Therefore, the utilization of a common network protocol such as the Internet Protocol is preferred. The theoretical part of this thesis work presents a general description of the wireless technologies used in industrial environments. Additionally, it discusses the different methodologies and algorithms used for the positioning of assets applications in wireless networks in more detail. Furthermore, an introduction to the latest efforts and systems developed to address the problem of position estimation of assets in wireless networks is provided. In order to understand the realization of the IP-based wireless sensor networks, a brief review of the operating systems supporting this characteristic is presented. Finally a survey about the IP-ready wireless sensor network is performed in order to select the most suitable platform to use in the practical part of this work. The practical part of this thesis work focuses on the implementation of a real-time position estimation tool for manufacturing assets based on a Wireless Sensor Network for indoor environments. The main purpose is to estimate the position of a pallet allocated on a light assembly manufacturing line. In addition, the wireless sensor network utilizes the Internet Protocol version 6 as the networking protocol. Furthermore, the estimation parameter utilized by the tool is the received signal strength. Consequently, the position estimation methodologies based on the received signal strength are implemented by this tool. Finally, the position estimation tool was tested which is documented in the results section. /Kir1

Analysis of the IEEE 802.15.4a ultra wideband physical layer through wireless sensor network simulations in OMNET++

Wireless Sensor Networks are the main representative of pervasive computing in large-scale physical environments. These networks consist of a large number of small, wireless devices embedded in the physical world to be used for surveillance, environmental monitoring or other data capture, processing and transfer applications. Ultra wideband has emerged as one of the newest and most promising concepts for wireless technology. Considering all its advantages it seems a likely communication technology candidate for future wireless sensor networks. This paper considers the viability of ultra wideband technology in wireless sensor networks by employing an IEEE 802.15.4a low-rate ultra wideband physical layer model in the OMNET++ simulation environment. An elaborate investigation into the inner workings of the IEEE 802.15.4a UWB physical layer is performed. Simulation experiments are used to provide a detailed analysis of the performance of the IEEE 802.15.4a UWB physical layer over several communication distances. A proposal for a cognitive, adaptive communication approach to optimize for speed and distance is also presented. AFRIKAANS : Draadlose Sensor Netwerke is die hoof verteenwoordiger vir deurdringende rekenarisering in groot skaal fisiese omgewings. Hierdie tipe netwerke bestaan uit ’n groot aantal klein, draadlose apparate wat in die fisiese wêreld ingesluit word vir die doel van bewaking, omgewings monitering en vele ander data opvang, verwerk en oordrag applikasies. Ultra wyeband het opgestaan as een van die nuutste en mees belowend konsepte vir draadlose kommunikasie tegnologie. As al die voordele van dié kommunikasie tegnologie in ag geneem word, blyk dit om ’n baie goeie kandidaat te wees vir gebruik in toekomstige draadlose sensor netwerke. Hierdie verhandeling oorweeg die vatbaarheid van die gebruik van die ultra wyeband tegnologie in draadlose sensor netwerke deur ’n IEEE 802.15.4a lae-tempo ultra wyeband fisiese laag model in die OMNET++ simulasie omgewing toe te pas. ’n Breedvoerige ondersoek word geloots om die fyn binneste werking van die IEEE 802.15.4a UWB fisiese laag te verstaan. Simulasie eksperimente word gebruik om ’n meer gedetaileerde analiese omtrent die werkverrigting van die IEEE 802.15.4a UWB fisiese laag te verkry oor verskillende kommunikasie afstande. ’n Voorstel vir ’n omgewings bewuste, aanpasbare kommunikasie tegniek word bespreek met die doel om die spoed en afstand van kommunikasie te optimiseer.Dissertation (MEng)--University of Pretoria, 2011.Electrical, Electronic and Computer Engineeringunrestricte

Radio Communications

In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks

New Approach of Indoor and Outdoor Localization Systems

Accurate determination of the mobile position constitutes the basis of many new applications. This book provides a detailed account of wireless systems for positioning, signal processing, radio localization techniques (Time Difference Of Arrival), performances evaluation, and localization applications. The first section is dedicated to Satellite systems for positioning like GPS, GNSS. The second section addresses the localization applications using the wireless sensor networks. Some techniques are introduced for localization systems, especially for indoor positioning, such as Ultra Wide Band (UWB), WIFI. The last section is dedicated to Coupled GPS and other sensors. Some results of simulations, implementation and tests are given to help readers grasp the presented techniques. This is an ideal book for students, PhD students, academics and engineers in the field of Communication, localization & Signal Processing, especially in indoor and outdoor localization domains

Architecture for multi-technology real-time location systems

[Abstract] Indoor localization is a problem that has generated much interest in recent years. Proximity marketing, eHealth, smart-parking and smart-cities, security and emergency units, logistics management, or industrial control systems are some pf the sectors that have demanded new Location Based Services (LBSs). These services are usually implemented using Wireless Sensor Networks (WSNs), capable of transmitting and receiving Radio Frequency (RF) signals in order to locate mobile devices attached to vehicles, people, or animals. While systems based on satellite systems such as GPS work correctly in outdoor scenarios, indoor localization is still a challenging field of study. On one hand, signal propagation problems are common, not only due to reflections and scattering due to the building structures, but also because of signal attenuation and fading caused mainly by people in movement. To overcome these issues, most of the approaches use several WSNs with a combination of multiple wireless technologies, such asWiFi, ZigBee or Bluetooth, some of them also available in mobile devices such as smartphones and tablets. On the other hand, data received from multiple devices must be filtered and combined by means of location algorithms and techniques in order to obtain precise and robust Real-Time Location Systems (RTLSs). Therefore, it is common to implement hybrid location systems with support for several technologies at the same time. Nevertheless, the development of such systems entails a huge complexity. Thus, one of most widely accepted alternatives is the implementation of software architectures for localization, which provide several benefits. First, accessing to different kinds of hardware devices entails fewer platform and technology restrictions. Second, some common tasks are easier to perform, such as sensor data gathering and storage. Finally, architectures provide utilities for adding and retrieving localization data, user management, or the possibility of using several mapping and coordinate systems. In this work, we present several solutions for implementing software architectures for localization. First, we propose a mono-technology architecture using only Received Signal Strength (RSS) signal levels for ranging, which evolves into a much more complete multitechnology architecture in a second stage. The proposed approaches implement several functionalities that resolve most of the hybrid RTLS system requirements, such as: • Multi-technology. • Support for several coordinate systems and mapping applications. • Data fusion. • Protection and security for both data and user access. • Standardized API for remote access. • Support for off-line data queries, not only on-line data and in real-time. • Depending on different user roles, it eases their tasks at different access levels: registration of WSNs, building blueprints, anchor and mobile node networks registration, generic sensor support, addition and retrieval of measurements and raw sensor data, multiple query support for filtered position estimations, etc. Moreover, we also contributed with different WSN physical layer implementations and experiments. And, due to collaborations with other research groups at different universities we have contributed with a customized hardware and software solution for localization based on RFID technology, as well as with the design of new antenna models based on linear-arrays of Electromagnetically Coupled Patchs (ECPs), valid for improving the WSN communication performance.[Resumo]O problema da localización no interior de edificios foi adquirindo cada vez máis importancia nos últimos anos debido á enorme demanda de novos servizos baseados en localización (LBSs). que apareeeron en todo tipo de sectores como eHealth. marketing por proximidade. smartparking e smart--cities. seguridade e emerxencias. loxística ou control industrial, entre outros. Estes sistemas habitualmente estan baseados na implementación de redes de sensores sen fíos (WSN) capaces de transmitir ou recibir sinais de radio (RF) para localizar dispositivos móbiles. xeralmente adheridos a vehículos. persoas ou animais. Menlres que en exteriores os sistemas de satélites baseados en tecnoloxías corno GPS funcionan correctamente na maioría de entornos. a localización en interiores non é unha tarefa sinxela de resolver e afnda inelúe múltiples retos. Principalmente aparecen problemas de propagación debido ás reflexións e rebotes dos sinais nas estruturas dos edificios. pero tarDén debido a atenuaci6ns e apantallamentos ocasionados xeralrnente por xente en movemento. Para resolver estes problemac;; é necesario implementar ac;; redes de sensores utilizando unha ou varias tecnoloxías sen fíos (como WiFi. ZigBee ou Bluetooth). a1gunhas delas disponibles en terminais sen fíos como smartphones ou tablets. Pero. por outra parte. tamén é necesario o uso de múltiples algoritmos e técnicas de localización para filtrar e posiblemente combinar os datos destas tecnoloxías. permitindo obter así sistemas de localización en tempo real (RTLS) robustos e coa maior precisión posible. Deste xeito. a aproximación máis usual na actualidade para resolver estos problemas é a implementación de sistemas de localización híbridos que soporten múltiples tecnoloxías simultaneamente. Nembargantes. O desenvolvemento destes sistemas leva implícito unha gran complexidade. Unha das alternativas comunmente aceptada é a implementación dunha arquitectura de software para localización, a cal ofrece varias vantaxes. En primeiro lugar, permite minimizar o número de restricci6ns multi-plataforma e multi-tecnoloxía á hora de acceder a distintos tipos de dispositivos hardware. En segundo lugar. facilítase a realización de tarefas comúns como a recolección e o almacenamento das medicións de sensores. Ademais, proporcinánse mecanismos para inserir e recuperar datos de localización ase como xestión de usuarios ou manipulación de múltiple" sistemas de mapas e coordenadas. Neste traballo presentamos varias solucións á hora de implementar arquitecturas de software para localización. comenzando por unha mono-tecnoloxía baseada unicarnente na recolección de niveis de sinal RSS, que evoluciona posteriormente a unha arquitectura multi-tecnoloxía. As solucións propostas ofrecen diferentes funcionalidades que resolven moitos dos problemas asociados aos sistemas híbridos RTLS, entre as que podemos destacar: • Multi-tecnoloxía. • Soporte de múltiples sistemas de coordenadas e de aplicacións de mapas. • Fusión de datos. • Protección e seguridad, tanto de datos como de acceso de usuarios. • API estandarizado para acceso remoto. • Soporte de consultas de datos off-line, non só on-line e en tempo real. • Facilidade de uso para os diferentes usuarios que utilicen a plataforma mediante chamadas a varios niveis: rexistro de WSNs, planos de edificios, rexistro de redes de áncoras e de nodos móviles, soporte de sensores xenéricos, inserción e consulta de medici6ns e de datos sensoriais en ero. inserción e consulta de posicións estimadas por algoritmos de localización, etc. Tamén contribuimos con múltiples implementacións da capa física de WSNs e experimentos. E grazas á colaboración con outros grupos de investigación de diferentes universidades puidemos, por unha parte, contribuir cunha solución de hardware e software para localización baseada en tecnoloxía RFID e, por outra parte, no deseño de novos modelos de antenas baseados en arrays lineais de ECPs, válidos para mellorar o rendemento das comunicacións en WSNs.[Resumen] El problema de la localización en el interior de edificios ha ido adquiriendo cada vez más importancia en los últimos años debido a la enorme demanda de nuevos servicios basados en localización (LBSs), que han ido apareciendo en la industria en sectores de todo tipo como eHeallb, marketing por proximidad, smart-parking y smart-cities, seguridad y emergeocias, logística o control industrial, entre otros. Estos sistemas habitualmeote se basan en la implementación de redes de sensores inalámbricos (WSN) capaces de transmitir o recibir señales de radio (RF) para localizar dispositivos móviles, generalmente adheridos a vehículos, personas o artimales. Mientras que en exteriores los sistemas satelitales basados en tecnologías como GPS funcionan correctamente en la mayoría de entornos, la localización en inleriores todavía plantea múltiples retos y no es una tarea sencilla de resolver. Principalmente aparecen problemas de propagación debido a los reflejos y rebotes de las sefiales en las estructuras de los edificios, pero también debido a atenuaciones y apantallamientos ocasionados generalmente por gente en movimiento. Para resolver estos problemas es necesario implementar Jas redes de sensores utilizando una o varias tecnologías inalámbricas (como pueden ser WiFí, ZigBee o Bluetooth), algunas de ellas disportibles en terminales inalámbricos como smartphones o tablets. Pero, por otra parte, también es necesario el uso de múltiples algoritmos y técnicas de localización, para filtrar y posiblemente combinar los datos de estas tecnologías, permitiendo obtener así sistemas de localización en tiempo real (RTLS) robustos y con la mayor precisión posible. De este modo, la aproximación más usual en la actualidad para resolver estos problemas es la implementación de sistemas de localización híbridos que soporten múltiples tecnologías simultáneamente. No obstante, el desarrollo de estos sistemas lleva implícito una gran complejidad. Una de las alternativas comúnmente aceptada es la implementación de una arquitectura de software para localización, que ofrece varias ventajas. En primer lugar, permite minimizar el número de restricciones multi-plataforma y multi-tecnología a la hora de acceder a distintos tipos de dispositivos hardware. En segundo lugar, se facilitan tareas comunes como la recolección y almacenamiento de las mediciones de los sensores. Además. se proveen mecanismos para insertar y recuperar datos de localización así como gestión de usuarios o manejo de múltiples sistemas de mapas y coordenadas. En este trabajo presentamos varias soluciones a la hora de implementar arquitecturas de software para localización, empezando por una mono-tecnología basada únicamente en la recoleccion de niveles de señal RSS, que se evoluciona posteriormente a una arquitectura mllltitecnología. Las soluciones propuestas ofrecen diferentes funcionalidades que resuelven muchos de los problemas asociados a los sistemas híbridos RTLS, entre las que podemos destacar: Multi-tecnología. Soporte de múltiples sistemas de coordenadas y de aplicaciones de mapas. • Fusión de datos. • Protección y seguridad, tanto de datos como de acceso de usuarios. • API estandarizado para acceso remoto. • Soporte de consultas de datos off-line, no solo on-line y en tiempo real. • Facilidad de uso para los diferentes usuarios que utilicen la plataforma, mediante llamadas a varios rtiveles: registro de WSNs, planos de edificios, registro de redes de anchors y de nodos móviles, soporte de sensores genéricos, inserción y consulta de mediciones y de datos sensoriales en crudo, inserción y consulta de posiciones estimadas por algoritmos de localización, etc. También contribuimos con múltiples implementaciones de la capa física de WSNs y experimentos. y gracias a la colaboración Con otros grupos de investigación de diferentes universidades hemos podido, por una parte, contribuir con una soluciÓn de hardware y software para localización basada en tecnología RFID y, por otra parte, en el diseño de nuevos modelos de antenas basados en arrays lineales de ECPs, válidos para mejorar el rendimiento de las comunicaciones en WSNs