Through-the-wall Imaging (TWI) is crucial for various applications such as law enforcement, rescue missions and defense. TWI methods aim to provide detailed information of spaces that cannot be seen directly. Current state-of-the-art TWI systems utilise ultra-wideband (UWB) signals to simultaneously achieve wall penetration and high resolution. These TWI systems transmit signals and mathematically back-project the reflected signals received to image the scenario of interest. However, these systems are diffraction-limited and encounter problems due to multipath signals in the presence of multiple scatterers. Time reversal (TR) methods have become popular for remote sensing because they can take advantage of multipath signals to achieve superresolution (resolution that beats the diffraction limit). The Decomposition Of the Time-Reversal Operator (DORT in its French acronym) and MUltiple SIgnal Classification (MUSIC) methods are both TR techniques which involve taking the Singular Value Decomposition (SVD) of the Multistatic Data Matrix (MDM) which contains the signals received from the target(s) to be located. The DORT and MUSIC imaging methods have generated a lot of interests due to their robustness and ability to locate multiple targets. However these TR-based methods encounter problems when the targets are behind an obstruction, particularly when the properties of the obstruction is unknown as is often the case in TWI applications. This dissertation introduces a novel total sub-MDM algorithm that uses the highly acclaimed MUSIC method to image targets hidden behind an obstruction and achieve superresolution. The algorithm utilises spatio-temporal windows to divide the full-MDM into sub-MDMs. The summation of all images obtained from each sub-MDM give a clearer image of a scenario than we can obtain using the full-MDM. Furthermore, we propose a total sub-differential MDM algorithm that uses the MUSIC method to obtain images of moving targets that are hiddenbehind an obstructing material.

Ces travaux portent sur le développement d'une technique de compression appliquée à la simplification des systèmes d'imagerie dans le domaine microonde. Cette approche repose sur le développement de composants passifs capables de compresser les ondes émises et reçues, autorisant ainsi une réduction du nombre de modules actifs nécessaires au fonctionnement de certaines architectures de radars. Ce principe est basé sur l'exploitation de la diversité modale présente dans les composants développés, le rendant compatible avec l'utilisation de très larges bandes passantes. Plusieurs preuves de concept sont réalisées au moyen de différents composants étudiés dans cet ouvrage, permettant d'adapter cette technique à de nombreuses spécifications d'architectures et de bandes passantes. / This work is focused on the development of a compressive technique applied to the simplification of microwave imaging systems. This principle is based on the study of passive devices able to compress transmitted and received waves, allowing for the reduction of the hardware complexity required by radar systems. This approach exploits the modal diversity in the developed components, making it compatible with ultra wide bandwidth. Several proofs of concept are presented using different passive devices, allowing this technique to be adapted to a large variety of architectures and bandwidths.

Abstract The value of wearable market is booming, especially in the healthcare application segment. This segment is driven by an increasing need for regular monitoring and early diagnosis of patients with growing prevalence of chronic diseases. Wireless communications worn in the close proximity of the body, the variety of applications, and their requirements set design considerations and challenges. In addition to the technical requirements, coexistence with adjacent wireless body area networks (WBANs) and other wireless systems need to be taken into account. A WBAN system needs to be highly reliable, low power, fast, and interference-immune. This thesis studies the performance of two different PHY layer implementations in interfered fading channels. The systems are the frequency modulated ultra wideband (FM-UWB), defined in the IEEE 802.15.6 standard, and narrowband SmartBAN physical layer. The performance of the systems was analyzed by using software simulators developed in Matlab. The author developed the SmartBAN simulator for the ETSI Technical Committee (TC) SmartBAN to study the performance of the new SmartBAN system. This is the first physical layer performance study of the SmartBAN system. In addition, the open literature does not offer similar results on the FM-UWB as presented in this thesis. Based on the results, it can be concluded that the FM-UWB is performing well in situations where high reliability and high interference tolerance is needed. In addition, the simplicity of the FM-UWB transceiver makes it more suitable than the direct sequence UWB (DS-UWB) for applications with data rates of hundreds of kbps. SmartBAN has the best performance in cases where more relaxed requirements for reliability and interference tolerance can be applied. Nevertheless, it became obvious that both systems need proper coexistence and interference mitigation mechanisms to ensure reliability in all scenarios. / Tiivistelmä Puettavien laitteiden markkina-arvo on voimakkaassa kasvussa erityisesti terveydenhuollon sovellusalueella. Tämän sovellusalueen kiihdyttimenä toimii yhä suurempi tarve potilaiden kunnon jatkuvalle tarkkailulle sekä kroonisille taudeille alttiimpien potilaiden varhaiselle diagnosoinnille. Langattoman kehoverkon (WBAN) suunnittelun suurimpia haasteita ovat langaton tiedonsiirto kehon läheisyydessä, erilaiset sovellustyypit sekä niiden vaatimukset. Teknisten vaatimusten lisäksi on myös huomioitava rinnakkaiset kehoverkot sekä muut langattomat järjestelmät. Kehoverkkojärjestelmän on oltava todella luotettava, matalatehoinen, nopea ja häiriösietoinen. Väitöskirjassa tutkitaan kahta kehoverkon fyysisen kerroksen toteutusta häipyvissä ja häirityissä kanavissa. Nämä toteutukset ovat IEEE 802.15.6 -standardissa määritelty taajuusmoduloitu ultralaajakaista (FM-UWB) sekä kapeakaistainen SmartBAN. Järjestelmien suorituskykyä analysoitiin Matlab-ohjelmistosimulaattoreiden avulla. Työssä kehitettiin SmartBAN-simulaattori ETSI Technical Committee (TC) SmartBAN -työryhmälle järjestelmän suorityskykytutkimukseen. Tässä työssä esitetään SmartBAN-järjestelmän fyysisen kerroksen suorituskykytulokset, jotka ovat ensimmäiset laatuaan. Lisäksi kirjallisuudesta ei löydy vastaavia tuloksia FM-UWB:n osalta, kuten tässä työssä on esitetty. Tuloksien pohjalta voidaan päätellä, että FM-UWB suoriutuu hyvin tilanteissa, joissa vaaditaan suurta luotettavuutta sekä suurta häiriönsietokykyä. Lisäksi yksinkertainen lähetin-vastaanotinrakenne tekee siitä kiinnostavamman vaihtoehdon kuin suorahajotettu UWB (DS-UWB) sovelluksille, jotka vaativat satojen kbps:n tiedonsiirtonopeutta. SmartBAN toimii hyvin tilanteissa, joissa näistä vaatimuksista voidaan hieman joustaa. Kuitenkin on selvää, että molemmat järjestelmät tarvitsevat sopivan rinnakkais- ja häiriönvaimennustekniikan taatakseen luotettavuuden kaikissa tapauksissa.

La technique de Georadar (GPR) est actuellement largement utilisée comme une technique non-destructive de sondage et d'imagerie dans plusieurs applications du génie civil qui concernent principalement: l'inspection des structures et des matériaux de construction, la cartographie des réseaux enterrés et des cavités, la caractérisation des fondations souterraines et du sol ainsi que l'estimation de la teneur en eau volumique du sous-sol. Le radar GPR est une technique en continuelle évolution en raison de l'intégration toujours plus poussée des équipements électroniques, des performances des calculateurs numériques, et des traitements du signal avancés. La promotion de cette technologie repose sur le développement de nouvelles configurations de systèmes et d'outils de traitement des données en vue de l'interprétation des images du sous-sol. Dans ce contexte, les travaux de cette thèse présentent tout d'abord le système GPR ULB (Ultra large bande) à double polarisation couplé au sol, lequel a été développé récemment au laboratoire. Par la suite, les traitement des données ont été focalisés sur le développement d'outils d'analyse en vue d'obtenir à partir des images brutes des images plus facilement lisibles par l'utilisateur afin d'améliorer l'interprétation des données GPR, en particulier dans le cadre de la détection de canalisations urbaines et la caractérisation des sols. Les moyens de traitement utilisés concernent l'élimination du clutter au cours d'une étape de prétraitement en utilisant des adaptations et des extensions des algorithmes fondés sur les techniques PCA et ICA. De plus, une technique de traitement d'image ‘'template matching” a été proposée pour faciliter la détection d'hyperbole dans une image Bscan de GPR. La diversité de polarisation est enfin abordée, dans le but de fournir des informations supplémentaires pour la détection d'objets diélectriques et des discontinuités du sous-sol. Les performances de nos outils d'analyse sont évaluées sur de données synthétiques (simulations 3D FDTD) et des données de mesures obtenues dans des environnements contrôlés. Pour cela, nous avons considéré différentes configurations de polarisation et des objets à caractéristiques diélectriques variées. Le potentiel de discrimination des cibles a été quantifié en utilisant le critère statistique fondé sur les courbes ROC / The Ground Penetrating Radar technique (GPR) is now widely used as a non destructive probing and imaging tool in several civil engineering applications mainly concerning inspection of construction materials and structures, mapping of underground utilities and voids, characterization of sub-structures, foundations and soil and estimation of sub-surface volumetric moisture content. GPR belongs to a continuously evolving field due to electronic integration, high-performance computing, and advanced signal processing. The promotion of this technology relies on the development of new system configurations and data processing tools for the interpretation of sub-surface images. In this context, the work presents first the dual polarization UWB ground coupled GPR system which has been developed recently. Then, the data processing has focalized on the development of analysis tools to transform the raw images in a more user-readable image in order to improve the GPR data interpretation especially within the scope of detection of urban pipes and soil characterization. The processing means used concern clutter removal in the pre-processing step using adaptations and extensions of the PCA and ICA algorithms. Moreover, a template matching image processing technique is presented to help the detection of hyperbola within GPR raw B-scan images. The dual polarization is finally shown to bring additional information and to improve the detection of buried dielectric objects or medium discontinuities. The performances of our analysis approaches are illustrated using synthetic data (3D FDTD simulations) and field-measurement data in controlled environments. Different polarization configurations and dielectric characteristics of objects have been considered. The potential for target discrimination has been quantified using statistical criteria such as ROC

The first part of this thesis develops methods for UWB communication. To meet the stringent regulatory body constraints, the physical layer signaling technique of the UWB transceiver should be optimally designed. We propose two signaling schemes which are variants of pulse position modulation (PPM) signaling for impulse radio (IR) UWB communication. We also discuss the detectors for the signaling schemes and evaluate the performance of these detectors.  IR-UWB can be used for precise range measurements as it provides a very high time resolution. This enables accurate time of arrival (TOA) estimations from which precise range values can be derived. We propose methods which use range information to arrive at optimal schedules for an all-to-all broadcast problem. Results indicate that throughput can be increased on average by three to ten times for typical network configurations compared to the traditional methods. Next, we discuss hypothesis testing in the context of UWB transceivers. We show that, when multiple detector outputs from a hardware platform are available, fusing the results from them can yield better performance in hypothesis testing than relying on a single detector output. In the second part of this thesis, the emphasis is placed on localization and joint estimation of location and communication parameters. Here, we focus on estimating the TOA of the signal. The wide bandwidth of the UWB signal requires high speed analog to digital converts (ADC) which makes the cost of the digital transceivers prohibitively high. To address this problem, we take two different strategies. In the first approach, we propose a multichannel receiver with each channel having a low-cost energy detector operating at a sub-Nyquist rate. In the second approach, we consider a compressive sampling based technique. Here, we propose a new acquisition front end, using which the sampling rate of the ADC can be significantly reduced. We extended the idea of compressive sampling based TOA estimation towards joint estimation of TOA and PPM symbols. Here, two signaling methods along with the algorithms are proposed based on the dynamicity of the target. They provide similar performance to the ML based estimation, however with a significant savings in the ADC resources. / <p>QC 20161205</p>

The thesis is focused on special corrugated reflectors for ultra-wideband antennas. Corrugated reflectors are divided into a type H and a type E. Both these types are mutually combined. All those reflectors are simulated and subsequently analyzed. The thesis also deals with different types of broadband dipoles, which are completed by investigated types of reflectors. Created reflector antennas are then compared. For antennas exhibiting the best parameters, we performed simulations of the transmission between two antennas. For the simulations, we used CST Microwave Studio. Selected antennas were manufactured and measured. Consequent simulations were aimed to detect differences between the simulated and measured results.

The necessity of interconnecting objects more and more, possibly with high mobility, has pushed the telecommunications industry to recently develop new wireless standards in order to guarantee tracking of devices and to provide integration with well-known worldwide networks such as the Internet. Within these standards the role played by power consumption is implicit, hence power consumption needs to be as low as possible in order to fulfill long-life requirements and to offer the opportunity of locating and moving smart objects in the coverage area while relying only on batteries as the device's power source.  Considering the importance of identifying and tracking these smart objects with high accuracy and high precision, this document propose an implementation of an IEEE 802.15.4a MAC layer, exploiting ultra-wideband wireless technology, with a time synchronization algorithm included for precise Time Difference of Arrival indoor positioning. Nevertheless, this thesis demonstrates the advantages of using UWB for indoor wireless communication, due to its accuracy in localization and its robustness against interference. A demonstration network has been analyzed consisting of four main base stations optimistically displaced at the corners of a room gathering timestamps from a central tag moving within the space where the UWB signal is within range. These timestamps are collected in one of the base station which plays the role of the coordinator and sends this information to a server which computes the position of the tag using TDOA formulation. The main focus of this work is the synchronization algorithms used to synchronize the four base stations and secondly to synchronize the coordinator with the tag. Particular interest is placed on the protocol, the kind of messages exchanged, and the procedure used to maintain a good level of synchronization and to avoid unwanted clock drifts. Moreover the thesis gives some hints of potential future improvements and proposes a possible solution for large-scale scenarios involving the installation of additional base stations for higher coverage and integration of a larger number of tags, with a focus on synchronization, collision avoidance, and routing procedures to better Fit the situation of a larger network and more tags.  As a result, all the assumptions and the methodologies applied give evidence of how difficult it is to meet contemporary requirements for position accuracy, low power consumption, limited memory, and small message exchange when utilizing low-power and lossy networks and to address problems which need to be further studied in the future. The results of this thesis project offer a good proof of the possibility to reach high accuracy in terms of localization when exploiting UWB radio technology and redundant time synchronization algorithms with the help of TDOA measurements. / Nödvändigheten av sammankopplade objekt mer och mer, eventuellt med hög rörlighet, har drivit telekombranschen till nyligen utveckla nya tråadlösa standarder för att garantera spåarning av enheter och att ge integration med välkända världsomspännande nätverk som Internet. Inom dessa standarder roll strömförbrukningen är implicit, måaste därför strömförbrukningen ska vara såa låag som möjligt för att uppfylla låang livslängd krav och erbjuda möjligheten att lokalisera och flytta smarta objekt i täckningsområadet medan enbart med hjälp av batterier som enhetens strömkälla. Med tanke påa vikten av att identiera och spåara dessa smarta objekt med hög noggrannhet och hög precision, detta dokument föreslåa ett genomförande av en IEEE 802.15.4a MAC-lager, utnyttja ultrabredbandsteknik tråadlös teknik, med en tidssynkronisering algoritm ingåar för exakt tidsskillnaden för ankomst inomhus positionering. Ändåa visar denna avhandling fördelarna med att använda UWB för inomhus tråadlös kommunikation, påa grund av dess noggrannhet i lokalisering och robusthet mot störningar. En demonstration nätverk har analyserats beståar av fyra huvudsakliga basstationer optimistiskt förskjutna i hörnen av ett rum samla tidsstämplar fråan en central tagg flyttar inom utrymme där UWB signalen är inom räckhåall.  Dessa tidsangivelser samlas i en av basstationen som spelar rollen av samordnare och skickar denna information till en server som beräknar position taggen med TDOA formulering. Tyngdpunkten i detta arbete är att synkronisering algoritmer som används för att synkronisera de fyra basstationer dels att synkronisera samordnaren med taggen. Särskilt intresse läggs vid protokollet, den typ av utbytta meddelanden och det förfarande som används för att upprätthåalla en god nivåa av synkronisering och för att undvika oönskade klocka drivor. Dessutom avhandlingen ger nåagra tips om potentiella framtida förbättringar och föreslåar en möjlig lösning för storskaliga scenarier som innebär installation av ytterligare basstationer för högre täckning och integration av ett större antal taggar, med fokus påa synkronisering, att undvika kollision och routing förfaranden för att bättre passa situationen i ett större nätverk och fler taggar.  Som ett resultat, som tillämpas alla antaganden och metoder vittnar om hur svåart det är att uppfylla dagens krav påa positionsnoggrannhet, låag strömförbrukning, begränsat minne, och småa utbyte av meddelanden vid användning med låag effekt och förstörande nätverk och att ta itu med problem som måaste studeras vidare i framtiden. Resultaten fråan denna avhandling projekt erbjuder en bra bevis påa möjligheten att nåa hög noggrannhet vad gäller lokalisering vid utnyttjande UWB radioteknik och redundanta tid algoritmer synkronisering med hjälp av TDOA mätningar.

Sprinting can be an important ability in sports, and there are many methods for measuring sprint performance. Two common methods are hand-held timing and fully automatic timing systems. However, hand-held timing is inaccurate due to reaction time, and fully automatic timing can be impractical since it involves complex equipment. Another way of measuring sprint performance is to obtain an athlete's velocity curve with a laser speed gun, although this requires that the laser is aimed towards the sprinter at all times. In this project, ultra-—widebandwhich is a radio technology capable of accurate —rangingis evaluated in a practical experiment by observing an athlete sprinting over a short distance. First, a pair of communicating ranging devices are developed. Measurements are then collected from the athlete and compared to video analysis to estimate the ranging error. The results suggest that ultra-wideband may be an alternative to laser speed guns for measuring sprint velocity. In the future, research should be focused on calibrating devices and testing ultra-wideband technology for longer sprint distances. / Att kunna springa snabbt kan vara en viktig egenskap inom sport och det finns många metoder för att mäta en sprint. Några exempel är manuell tidtagning, automatiska tidtagningssystem eller laserpistol för att mäta hastighet. Ofta är manuell tidtagning inte tillräckligt noggrann på grund av reaktionstid och automatisk tidtagning kan vara opraktisk för de flesta utövare. Dessutom måste en laserpistol alltid vara riktad mot atleten för ge mätningar. I det här projektet testas ultrabredbandsteknik – vilket är en typ av radioteknik som kan ge noggrann distansmätning – i ett praktiskt experiment genom att observera en atlet i en kort sprint. Först utvecklas ett par apparater som kan avläsa distansen mellan varandra. Därefter samlas mätningar från atleten som jämförs med videoanalys för att bestämma mätningsfelet. Det erhållna resultatet föreslår att ultrabredbandsteknik kan vara ett alternativ till laserpistoler för hastighetsmätning inom sprint. Framöver borde fokus inom forskningen ligga på att kalibrera apparater och testa tekniken över längre sprintdistanser.

Falls in the disabled and elderly people have been a cause of concern as they can be immobilized by the fall and have no way to contact others and seek assistance. The proposed frequency modulated continuous wave (FMCW) short range radar (SRR) system, which uses ultra-wideband (UWB) signals can provide immediate assistance by monitoring and detecting fall events. The unique characteristics of this system allow for a frequency-based modulation system to carry out triangulation and sense the location of the fall through the usage of a continuous chirp signal that linearly sweeps frequency. This project focuses on the development, design and simulation of a ring oscillator that exhibits the frequency modulated signal on a single integrated circuit chip. The ring oscillator is controlled by a voltage ramp signal generator and a voltage to current (V-I) converter. The circuit is designed in Cadence using TSMC 180nm process technology and operates in the frequency range of 3.409 GHz to 5.349 GHz with a spectral bandwidth of 1.94 GHz, which meets the Federal Communications Commission’s standards for unlicensed ultra-wideband transmissions.

Global navigation satellite systems (GNSS) have radically changed business, industry, and society, shaping the way we transport, navigate, and generally live every day. After all these years, however, GNSS location information remains only valuable outdoors, leaving indoor environments where people dwell most of the time without proper localization support. Many technologies and systems have approached this problem including optical, inertial, ultrasonic, and radio-frequency (RF), to name a few; yet the problem remains. In this thesis, inspired by the indisputable success of GNSS and the re-emergence of ultra-wideband (UWB) radios to the forefront of technology, we aim to change the state of affairs in RF localization by proposing novel clean-slate UWB ranging and localization schemes based on concurrent transmissions. These are generally considered harmful for communication but become a rich source of localization information when combined with knowledge of the channel impulse response (CIR). Our first novel contribution lies in the concept of concurrent ranging, which allows mobile nodes to simultaneously measure the distance to multiple devices—hereafter, called responders—removing the need for the wasteful long packet exchanges traditionally used for ranging and localization. Different from conventional schemes, which spread responder transmissions over time, we force responders to transmit concurrently and let their signals “fuse” in the wireless channel; the resulting impulse response, as measured by commercial UWB radios, contains all the necessary timing information to extract the desired distance to all responders. This first contribution, however, also serves us to realize the many challenges ahead to unlock the real power of concurrent transmissions for localization. We address these challenges along the way, starting with Chorus, our second contribution. Chorus exploits an anchor infrastructure that transmits packets concurrently. Mobile nodes listen for these transmissions and measure from the CIR the time difference of arrival (TDoA) of the concurrent signals, privately computing their own position at a high rate using hyperbolic localization. This reverse TDoA scheme, although simple in concept, is extremely powerful in that it enables passive self-localization of infinitely many targets at once, a feature largely missing in the RF literature. In Chorus, we address the difficult challenges to reliably detect and identify the signal from the different responders. Yet, the limited transmission precision of commercial UWB transceivers constrains the many benefits of Chorus. In this context, we i) contribute a model to ascertain the impact of the transmission uncertainty on concurrent transmissions, and ii) address the issue with a compensation mechanism that fine-tunes the local oscillator frequency of responders while they prepare to transmit, allowing us to simultaneously tackle the impact of clock drift on distance estimation. We demonstrate in our evaluation that with this compensation mechanism we can schedule transmissions with &lt; 1 ns error, removing the need to share timestamps to precisely measure distance. We rebuild concurrent ranging around this mechanism, obtaining decimeter-level ranging and localization at a fraction of the cost of conventional schemes. These results turn concurrent ranging into an immediately applicable technique that new systems can now exploit, benefiting from a different set of trade-offs hitherto unavailable. Further, the TX compensation mechanism can be directly applied to Chorus, similarly making fast and accurate passive self-localization a tangible reality. We continue our endeavor with a systematic characterization of the conditions under which UWB concurrent transmissions succeed to provide reliable ranging and communication across different complex channels. The results we put forth empower developers to fully exploit concurrent transmissions in their designs, potentially inspiring a new wave of ranging, and also communication, primitives that can bring to UWB the same striking benefits found in low-power narrowband radios. The thesis is completed by looking at other challenges preventing the wide adoption of UWB localization systems, namely, large-scale operation, energy efficiency, and the complexity to install anchor deployments. We tackle these aspects in the last part of the thesis with three additional contributions. First, we propose Talla, a TDoA system that provides seamless large-scale localization for many tags across cells of time-synchronized anchors. Secondly, we fuse UWB ranging with odometry information and build an uncertainty model that only triggers new UWB estimates if and when needed, reducing consumption and channel utilization while satisfying the application-specific demands in terms of accuracy. And thirdly, we build state-of-the-art mechanisms to automatically compute the positions of all anchors deployed across large areas based on ranging information, facilitating anchor network deployment for the many UWB-based real-time location systems (RTLS) to come. Overall, this thesis changes the landscape of UWB localization with a new set of potentially disruptive schemes and systems that exploit the peculiar benefits of concurrent transmissions and that consequently redefine the trade-offs of the technology.