Continuous-wave frequency-modulated radar, or FMCW radar, is simple in design, small in size and weight and uses low transmitting power. The range resolution depends on the bandwidth. FMCWradar is used in applications ranging from guided weapons systems to vehicle collision avoidance systems. Measuring the distance to the target is the essential feature of FMCW radar. Firstly, this thesis introduces the basic structure of the FMCW radar and the principle formeasuring distance. Secondly, by using software-dened radio (SDR),FMCW radar can be implemented and congured with a reduced costand complexity. In this report, the radar is implemented by means ofthe software GNU Radio Companion with a test signal. HackRF may be used in future work with an osmocom source instead of the testsignal.

Falls are a cause of concern for the elderly since it can render a person immobile. A monitoring system can summon immediate aid by the automatic detection of fall events. The application of ultra-wideband (UWB) signals for a monitoring system was chosen due to its unique characteristics such as wide spectrum, immunity to interference, penetrability, and application for the detection of people. Part of this monitoring system is boundary detection with the purpose of isolating the location of fall events and to function as a mask to define an area of interest. A study of various localizing methods using measurements such as power, distance, and angle with ultra-wideband is presented. A frequency modulated continuous wave (FMCW) based system is an acceptable solution for boundary detection. A FMCW system measures distance with UWB signals. With the addition of a unique reflector, the system is able to identify the reflector via the return frequency-spectrum fingerprint. With distance and the addition angle measurements, the system can determine the boundary with a sensor located at a single location.

<p>The University of Massachusetts S-band frequency-modulated, continuous-wave radar (UMass FMCW) was deployed to monitor the growth of the convective boundary layer over northern Alabama during the Verification of the Origins of Rotation in Tornadoes Experiment-Southeast (VORTEX-SE). The Doppler spectra collected in 2016 from the vertically-pointing UMass FMCW contain “spurs”, or spurious spectral peaks, caused by high-voltage switching power supplies in the traveling wave tube amplifier. In the original data processing scheme for this radar, a median filtering method was used to eliminate most of the spurs, but the largest ones persisted, which significantly degraded the quality of derived radar moments (e.g., reflectivity, Doppler velocity, and spectrum width) and hindered further analysis of these data (e.g., boundary layer height tracking). </p><p><br></p><p>In this study, a novel “in-painting” image processing technique was applied to remove the spurs in the Doppler spectra. We hypothesized the in-painting method would exhibit superior performance to the median filter at removing large spectral peaks, and also improve downstream radar products derived from the spectra. First, a Laplacian filter identified and masked spikes in the spectra that were characteristic of the spurs in shape and amplitude. The in-painting method then filled in masked areas based on surrounding data. Via a histogram analysis, the in-painting method was found to be more effective than the median filter at removing the large spurs from the Doppler spectra. The radar moments were then recomputed using a coherent power (CP) technique, resulting in cleaner reflectivity, Doppler velocity, and spectrum width data. Improvement was also found downstream when a boundary layer height detection algorithm was applied to the moments generated from the in- painted spectra. Output from the boundary layer height detection algorithm was then used to verify forecast boundary layer height from the Advanced Regional Prediction System (ARPS) model for the 31 March 2016 VORTEX-SE tornadic case study. </p>

Background. As smart appliances become more attractive, the demand from public consumers grows, and producers are in search of innovative technologies that may aid in the creation of smart homes. Current products may use screens and buttons, voice commands and motion detection to create an interactive experience for consumers. A rather new technology that has gathered attention in recent years is millimetre wave radar sensors (mmWave). This technology uses electromagnetic waves to detect objects in the vicinity of the physical sensor; it may detect both the range, velocity and orientation of an object in relation to itself. The current research has had a main focus in automotive and industrial industries, and the technology has thus far been applied to areas such as vital signs monitoring, people counting, motion control, object detection and collision aversion among others. An attractive feature for use in smart homes that the sensor provides, or rather lacks, is its inability to identify different people. As the information gathered is a point cloud -- in low resolution -- any monitored people retain their privacy under normal circumstances. Objectives. The aim of this thesis is to verify the usability of mmWave sensors in smart homes, as well as reaching an initial understanding of people's opinions regarding the mmWave technology. Method. Experiments are performed to test how well the mmWave sensors can determine if a person is standing, sitting, lying or if they have fallen. The approach for the developed program to make these predictions are done through simple algorithms. Experiments were performed in an environment that was meant to mimic the conditions of a home. Participants were also asked about their opinion of potentially using the technology in their home, both regarding imagined usage and whether the sensor would cause them any discomfort. Results. The results show that while the implemented software in this thesis helps validate the proof of concept for the intended purpose, the technology shows a lot of promise for the future. Further algorithmic efforts will however be required to reach the desired maturity. The opinions of the participant show a generally positive response in using the sensor, however, they also note that if the sensor is to be used in their home, any data gathered should be both available and in control of the consumer to ease suspicions of misuse. Conclusions. The authors conclude that while not yet quite ready, the sensor is indeed a probable candidate to be integrated into smart homes of the future. / Bakgrund. Då smarta apparater blir mer attraktiva växer efterfrågan för dessa produkter. Tillverkare söker därmed efter innovativa teknologier som kan bistå i skapandet av smarta hem. De produkter som finns idag använder sig av skärmar och knappar, röstkommandon och rörelsedetektering för att skapa en interaktiv upplevelse för användarna. En relativt ny tekonologi som har fått uppmärksamhet de senaste åren är radarsensorer med millimetervågor (mmWave). Denna teknologi använder elektromagnetiska vågor för att upptäcka föremål i sin närhet; sensorn kan känna av både avstånd, hastighet och orientering av ett objekt i relation till sig själv. Existerande forskning har framförallt fokuserat på bil- och tillverkningsindustrierna, och teknologin har hittills applicerats på områden som bland annat övervakning av vitala tecken, räkning av människor, rörelsestyrning, detektion av föremål och kollisionsundvikande system. En attraktiv funktionalitet för användande i smarta hem som den här sortens sensor tillhandahåller, eller snarare saknar, är dess oförmåga att identifiera olika människor. Eftersom datan sensorn samlar in består av ett punktmoln -- i låg upplösning -- kommer den under normala förhållanden inte inkräkta på privatliv och integritet hos användarna. Syfte. Målet med detta projekt är att undersöka användbarheten av mmWave-sensorer i smarta hem, samt att komma till en initial insikt om folks åsikter angående mmWave-teknologin. Metod. Experiment har utförts för att verifiera hur väl sensorerna kan avgöra om en person står upp, sitter ner, ligger ner eller har fallit. Mjukvaran som utvecklades för att avgöra vilken handling en person utför tar sig an detta med hjälp av enkla algoritmer. Experimenten utfördes i en miljö som var tänkt att efterlikna förhållandena i ett hem. Deltagarna fick också frågor angående sina åsikter om att potentiellt använda teknologin i sina hem, både vad gäller möjliga användningsområden samt huruvida varandet av sensorn i hemmet skulle orsaka dem något obehag. Resultat. Resultaten visar att även om den skapade mjukvaran är otillförlitlig för det tänkta användandet så visar teknologin lovande tecken för framtiden. Deltagarnas åsikter visar också på ett generellt sett positivt gensvar gentemot användandet av sensorn, men de påpekar också att om sensorn ska användas i deras hem bör all data vara tillgänglig för och kontrollerad av användaren, allt för att lindra möjliga misstankar om missbruk av datan. Slutsatser. Författarna kommer fram till att även om de inte än är riktigt redo, så är mmWave-sensorerna en sannolik kandidat till att användas i framtidens smarta hem.

Falls are a cause of concern for the elderly because it can make them unable to call for help. A monitoring system can detect automatically their immobility and provide help to the elderly if they fall. Ultra-wide band signals for a monitoring system is an excellent choice since it has low enough power to not interfere with other medical and household electronics as well as being able to transmit data to a central monitoring unit. One part of this monitoring system is a boundary detection system used to verify that the monitoring system is not capturing events outside the monitoring region such as an event outside the house or in a neighboring room. The work presented in the paper, “A Frequency-Modulated Continuous Wave-Based Boundary Detection System for Determination of Monitoring Region for an Indoor Ultra-Wideband Short Range Radar-Based Eldercare Monitoring System” has determined that a frequency modulated continuous wave (FMCW) based system is an acceptable solution for boundary detection. A FMCW system can measure distance with less than 10cm accuracy if the chosen spectrum bandwidth is 1GHz or more. This thesis presents the design of a low cost approach to small PCB footprint distance detection circuitry for the boundary detection system.

In this report, remote sensing with Light Detection and Ranging (LIDAR) was demonstrated. In particular, a Frequency Modulated Continuous Wave (FMCW) LIDAR was used to reconstruct the motion of a moving target. Measurements were performed at the single photon level using a Superconducting Nanowire Single Photon Detector (SNSPD) and velocity and distance time series were reconstructed. The limitations of the technique were investigated by comparing three different targets. Furthermore, vibration sensing was performed where the vibrational modes were successfully reconstructed for a speaker. Additionally, multi-pitch decomposition was demonstrated and the Signal to Noise Ratio (SNR) - dependency on speaker frequency was studied.

Cette thèse, réalisée en partenariat avec Rockwell-Collins France, s'inscrit dans le cadre du développement d'un radar FMCW aéroporté de détection d'obstacles fonctionnant en bande X. Dans cette thèse, nous nous plaçons dans le contexte plus général de détection de cibles présentant un risque de collision avec le porteur radar dans du fouillis de sol. Les performances de détection des cibles d'intérêt diminuent grandement lorsqu'elles se retrouvent dans les zones de fouillis. Le principal objectif de cette thèse réside ainsi dans la conception de traitements en vue d'améliorer les capacités de détection et de reconnaissance de cibles présentant un risque de collision avec le porteur radar dans les zones de fouillis de sol. Dans un premier temps, nous effectuons une revue des traitements adaptés à la détection d'obstacles par un radar aéroporté FMCW: formation de faisceaux conventionnelle, compensation de migration distance, et création d'une cartographie distance-vitesse par double FFT. Dans un second temps, nous utilisons ensuite un traitement d'antennes adaptatif pour séparer en élévation le fouillis de sol et d'éventuels obstacles situés au-dessus du sol pouvant présenter un risque pour le porteur (câbles, pylônes, immeubles, ...). Dans la seconde partie de cette thèse, nous incluons une information supplémentaire sur le signal temporel d'une case distance avec un temps d'intégration plus long~: la variation de fréquence Doppler des cibles. Une cible de collision ou un câble ne changent pas de fréquence tandis qu'un élément au sol aura une variation connue dépendant de la vitesse du porteur et de son angle de vue. Cette information nous a tout d'abord permis de séparer le signal d'un pylône et d'un câble, pour ensuite séparer la cible de collision du fouillis de sol. Enfin, nous effectuons la détection adaptative d'une cible mobile de collision étendue en distance et noyée dans le fouillis de sol. Les algorithmes développés dans cette thèse ont été testés avec succès sur données expérimentales. / This thesis, in collaboration with Rockwell-Collins France, forms part of the development of an X-band FMCW airborne radar designed for obstacles detection and collision avoidance. More precisely, this thesis deals with the problem of detecting targets which exhibit a collision trajectory with the radar carrier, in presence of ground clutter. Target detection performances are highly degraded when the targets of interest fall into ground clutter. The main goal of this thesis is to develop signal processing methods to increase radar detection capacities and recognition for collision targets inside ground clutter. First, we give a brief review of signal processing methods for target detection using an airborne FMCW radar : conventional beamforming, range migration compensation, double-FFTs for Range-Doppler Map visualization. We then derive an adaptive antenna array processing to separate ground clutter and fixed hazardous obstacles above the ground (cables, pylons, buildings, ...) using their difference in elevation angle. In the second part of this thesis, we use a long integration time and include extra information on the time model of a range cell signal : Doppler frequency variation. A collision target does not exhibit Doppler frequency variation, whereas fixed obstacle or ground clutter exhibits a known variation depending on the carrier velocity and the aspect angle. We take advantage of this variation first to separate a cable from a pylon, and then separate collision target from ground clutter. We finally tackle the problem of adaptively detecting a collision mobile spread target in ground clutter region. The proposed algorithms in this thesis have been successively tested on experimental data.

Phased array based systems have extending applications in electronic warfare, radio astronomy, civilian applications with technological advancements. The main virtue offered by these systems is the creation of agile beams with utilization of phase shifting or delay elements. In fact, the desire for flexible steering comes with a cost. Frequency Diverse Array (FDA) concept is another approach to beam steering problem. In this context, the subsequent antenna elements are fed with stepped discrete frequencies causing continuous scanning of space in time. So a range-angle dependent scanning is made possible. Also the diversity of waveforms between the antennas is another area of research especially in Moving Target Indicator (MTI) applications. Although several implementation schemes were proposed, the costs and the non-ideal behavior of building blocks make the schemes hard to implement. During this study, a new implementation scheme is proposed where a Linear Frequency Modulated Continuous Wave (LFMCW, Linear FMCW) source is used for feeding a special beam forming network, where the subsequent outputs of the beam forming network have uniform delays. The dynamic behavior of the source and the uniform (or non-uniform) delay provided by the beam forming network create the required frequency steps between antenna elements as described in conventional FDA. So, the implementation of FDA concept requires just the design of the source, beam forming network and the antenna array. Throughout the study, mathematical analysis of both conventional FDA and the LFMCW based FDA is made and various implementations are realized. Justification of the mathematical derivations is made by the results of the measurements with the implemented structures. Besides, analysis and simulation of the array in a radar environment with various scenarios are performed. The drawbacks and the proposals for overcoming these drawbacks are also reported during the analysis, which will be useful for future studies on the subject.

Die Interaktion zwischen Mensch und Computer ist zu einem Teil unseres täglichen Lebens geworden. Radarsensoren sind aufgrund ihrer geringen Größe, ihres niedrigen Stromverbrauchs und ihrer Erschwinglichkeit sehr vielversprechend. Im Vergleich zu anderen Sensoren wie Kameras und LIDAR kann RADAR in einer Vielzahl von Umgebungen eingesetzt werden, und wird dabei nicht durch Licht beeinträchtigt. Vor allem aber besteht keine Gefahr, dass die Privatsphäre des Benutzers verletzt wird. Unter den vielen Radararten wird das FMCW-Radar für die Gestenerkennung genutzt, da es mehrere Ziele beobachten, Reichweite, Geschwindigkeit und Winkel messen kann und die Hardware und Signalverarbeitung relativ einfach sind. Die radargestützte Gestenerkennung kann in einer Vielzahl von Bereichen eingesetzt werden. So kann z. B. bei Gesundheits- und Sicherheitsaspekten durch den Einsatz radargestützter Gestenerkennungssysteme Körperkontakt vermieden und die Möglichkeit einer Kontamination verringert werden. Auch in der Automobilbranche kann die berührungslose Steuerung bestimmter Funktionen, wie z. B. das Einschalten der Klimaanlage, das Benutzererlebnis verbessern und zu einem sichereren Fahrverhalten beitragen. Bei der Implementierung eines auf künstlicher Intelligenz basierenden Gestenerkennungssystems unter Verwendung von RADAR gibt es noch viele Herausforderungen, wie z. B. die Interpretation von Daten, das Sammeln von Trainingsdaten, die Optimierung der Berechnungskomplexität und die Verbesserung der Systemrobustheit. Diese Arbeit konzentriert sich auf die Bewältigung dieser Herausforderungen. Diese Arbeit befasst sich mit wichtigen Aspekten von Gestenerkennungssystemen. Von der Radarsignalverarbeitung, über maschinelle Lernmodelle, Datenerweiterung bis hin zu Multisensorsystemen werden die Herausforderungen der realen Welt angegangen. Damit wird der Grundstein für den umfassenden Einsatz von Gestenerkennungssystemen in der Praxis gelegt. / Human-computer interaction has become part of our daily lives. RADAR stands out as a very promising sensor, with its small size, low power consumption, and affordability. Compared to other sensors, such as cameras and LIDAR, RADAR can work in a variety of environments, and it is not affected by light. Most importantly, there is no risk of infringing on user's privacy. Among the many types of RADAR, FMCW RADAR is utilised for gesture recognition due to its ability to observe multiple targets and to measure range, velocity and angle, as well as its relatively simple hardware and signal processing. RADAR-based gesture recognition can be applied in a variety of domains. For example, for health and safety considerations, the use of RADAR-based gesture recognition systems can avoid physical contact and reduce the possibility of contamination. Similarly, in automotive applications, contactless control of certain functions, such as turning on the air conditioning, can improve the user experience and contribute to safer driving. There are still many challenges in implementing an artificial intelligence-based gesture recognition system using RADAR, such as interpreting data, collecting training data, optimising computational complexity and improving system robustness. This work will focus on addressing these challenges. This thesis addresses key aspects of gesture recognition systems. From RADAR signal processing, machine learning models, data augmentation to multi-sensor systems, the challenges posed by real-world scenarios are tackled. This lays the foundation for a comprehensive deployment of gesture recognition systems for many practical applications.

Un nouvel axe de recherche sur les réseaux de capteurs a été initié au LAAS par la réalisation de nouveaux capteurs sans fil passifs utilisant une transduction électromagnétique dans la détection de pression et de gaz. Ces capteurs fortement intégrés ne nécessitent aucune alimentation embarquée et leur fréquence de fonctionnement se situe dans la bande de fréquence Ka (26 à 40 GHz). Cette thèse s'inscrit donc dans la conception et la réalisation d'un lecteur adapté à l'interrogation à distance de capteurs à transduction électromagnétique. Son principe de fonctionnement est basé sur une technologie radar de type FMCW. L'avantage principal de la lecture radar des données issues de ce type de capteurs passifs réside dans la possibilité d'avoir des portées de plusieurs dizaines de mètres, bien supérieures à celles classiquement obtenues dans les technologies SAW ou RFID. Dans une première étape est présenté le principe de fonctionnement du lecteur radar et la réalisation de deux prototypes centrés sur les fréquences de 3GHz et 30GHz. Une étude du spectre de la sortie radar, appelé signal de battement radar, est abordée afin de montrer comment les positions et les mesures des capteurs sont lues à distance par ce type de lecteur. Par la suite, un travail d'analyse de la communication sans fil permet de déterminer les paramètres de rétrodiffusion électromagnétique à prendre en compte, tels que les impédances et les fréquences de fonctionnement des capteurs. Ces paramètres sont la base d'une optimisation du système global en termes de sensibilité, de portée radar et des niveaux minimaux de Surface Equivalente Radar (SER) des cibles interrogées. La validation de cette analyse se borne à la mesure de la portée maximale associée à ce type de lecteur et aux différentes mesures de SER de plusieurs types de capteurs dans les bandes de fréquence de 3GHz et 30GHz. Deux principes d'identification de cellules passives sont ensuite présentés. Le premier est basé sur l'utilisation des deux modes de rétrodiffusion de la SER d'un capteur (mode de structure et mode d'antenne) favorisant dans le même temps l'identification sur un mode et la mesure de la grandeur physique sur l'autre, a distance du lecteur. Le deuxième principe utilise le spectre d'un diffuseur multi-bande dont sa SER reconfigurable permet d'associer l'identification de chaque capteur dans un réseau, à la manière d'un code barre. En conclusion, les résultats obtenus dans cette étude valident le principe d'interrogation à longue distance de réseau de capteurs passifs et ouvrent de nouvelles perspectives sur la conception de nouvelles cellules de mesures pour de nouvelles applications dans les secteurs de l'aéronautique, du nucléaire, et de l'environnement. / A new development on sensor networks has been started by LAAS to implement new wireless sensors using passive electromagnetic transduction in the detection of pressure and gas. These highly integrated sensors require no power and the embedded operating frequency is in the Ka band (26 to 40GHz). This thesis is on the design and the realization of a reader suitable for remote sensing of sensor electromagnetic transduction. Its working principle is based on an FMCW radar technology. The main advantage of this radar when reading passive sensors is the ability to have ranges of several tens of meters, much higher than those obtained with conventional SAW or RFID technology. In the first step, the principle of operation of the reader and also the realization of two prototypes focused on the frequencies of 3GHz and 30GHz are presented. A study of the output radar spectrum, called beat signal radar, is discussed to show how the positions and measurements from the sensors are read remotely by the reader. Afterwards, an analysis of the wireless communication is performed to take into account parameters of electromagnetic backscatter such as the impedance and operating frequency of these sensors. These parameters are the basis of an optimization of the global system in terms of sensitivity radar range and the minimal levels of Radar Cross Section (RCS) of the interrogated targets.The validation of this analysis is limited by the reader's maximum range and by various RCS measurements of several types of sensors in the frequency bands of 3GHz and 30GHz. Two principles of sensor passive identification are then presented. The first is based on the simultaneous use of both modes of the sensor's RCS (structural mode and antenna mode), facilitating the identification by one mode and measuring the physical quantity using the other mode. The second principle uses the spectrum of a multiband scatterer where its reconfigurable RCS can associate the identification of each sensor in a network, such as a barcode. In conclusion, the result obtained in this thesis validate the principle of an interrogating network of passive sensors over a long reading range and consequently open a new way of sensor design for future aerospace, nuclear and environment applications.