L’objectif de cette thèse est de développer de nouvelles solutions pour détecter et localiser des sources électromagnétiques radar au niveau d'une unique station de réception en exploitant les signaux directs et indirects reçus. Dans le cadre de notre étude, nous avons dans un premier temps développé une modélisation du signal reçu au niveau d'un récepteur en tenant compte des caractéristiques des émetteurs et de la zone environnante. L'évaluation de cette modélisation a été effectuée en s'appuyant sur un cas particulier de détection et de localisation des réflecteurs. Ce dernier, traité dans la littérature, repose sur l’exploitation des trajets multiples. Ces derniers peuvent être également utilisés pour localiser des sources d’émission. Néanmoins, la plupart des méthodes existantes se basent sur des réflexions dites spéculaires. Les techniques employant les réflexions non spéculaires sur un réflecteur quelconque pour localiser des sources d'émission dans un environnement inconnu font l'objet de peu de publications dans la littérature ouverte. La méthode de localisation que nous proposons a l'avantage de n'employer qu'un récepteur fixe mesurant seulement deux types de grandeurs : les angles d'arrivée (AOA) et les différences de temps d'arrivée (TDOA). En pratique, un problème d'affectation doit être résolu avant de procéder à la localisation des émetteurs et des réflecteurs. Le problème consiste à affecter chaque paire de mesures TDOAAOA à un réflecteur donné, en supposant que chaque paire a déjà été affectée à un émetteur.La méthode que nous avons développée a été testée et évaluée, d'une part grâce à des données simulées et d'autre part en utilisant des mesures réelles. / The purpose of this work is to develop new methods for the detection and the location of radar sources. The developed approach exploits the direct and indirect signals received at the receiving point. In our study, we first develop a model of these signals that takes into account the characteristics of the transmitters and the reflectors. We evaluate this model by simulating a particular case of reflectors detection and location, defined in the literature. Our goal is to use the multipaths to locate emission sources. Most existing methods are based on specular reflections. Methods based on non-specular reflections, to locate emission sources in an unknown environment, are rarely studied in the literature. In our study, we propose a new location method that uses a fixed receiver measuring the Angle of Arrival (AOA) and Time Difference of Arrival (TDOA). In practice, an assignment problem must be solved before locating the emitters and reflectors. The problem is to assign each pair of TDOA-AOA measurements to a given reflector, assuming that each pair has already been assigned to a transmitter. The method developed has been tested and evaluated by using simulated data and real measurements.

I Sverige finns det ungefär 25 000 riskklassade förorenade områden samt ännu fler områden som potentiellt är förorenade. Naturvårdsverket har tagit fram generella riktvärden för olika förorenade ämnen. Halter över riktvärdena antyder att risken för negativa effekter på människan eller miljön bedöms vara stor och att efterbehandling av området är aktuellt. Ett vanligt, men kostsamt efterbehandlingsalternativ är urschaktning och bortforsling av jord innehållandes halter av ämnen över riktvärdena. Ett intresse finns för att utveckla lätt tillämpbara metoder för platsspecifik riskbedömning av mark i syfte att skydda markmiljön och dess funktioner. Mikroorganismer som ingår i kvävets kretslopp utför nyckelfunktioner i jorden. Flera studier indikerar att dessa mikroorganismers abundans och aktivitet påverkas av flera olika markföroreningar. Inom forskningsprojektet APPLICERA har ett lysimeterexperiment genomförts där två jordar, med olika egenskaper med avseende på bland annat kornstorleksfördelning och pH (svagt basisk sandy loam respektive sur sand), förorenats med koppar respektive PAH:er i varierande halter. Halterna motsvarar riktvärden för känslig markanvändning (KM), mindre känslig markanvändning (MKM) och 3xMKM. Provtagning av jorden har skett vid tre tillfällen under en period av 16 månader. I detta examensarbete har nitrifierande mikroorganismers potential för att användas som indikatorer för förändrad markfunktion i förorenad jord undersökts. Detta har gjorts genom att kvantifiera ammoniakoxiderande arkéer (AOA), ammoniakoxiderande bakterier (AOB) samt de nitritoxiderande bakteriesläktena Nitrospira och Nitrobacter i jord som provtagits vid de olika tidpunkterna i lysimeterexperimentet. Mätning av potentiell ammoniakoxidation (PAO) har skett för jord från det sista provtagningstillfället. Resultaten visade att abundansen av mikroorganismerna generellt var större i den svagt basiska jorden klassificerad som sandy loam än i den sura jorden klassificerad som sand. Med tiden minskade AOA:s abundans för den högsta koncentrationen av koppar och PAH, särskilt utpräglad var minskningen i den sura jorden. Även Nitrospira minskade i abundans i PAH-förorenad jord för båda jordtyperna, dock kunde en minskning i abundans i kopparförorenad jord statistisk endast säkerställas för den sura jorden. AOB:s och Nitrobacters abundans visade inte på någon tydlig uppåt- eller nedåtgående trend varken över tid eller för ökande föroreningshalt. Skillnaden i kvantitet av mikroorganismer mellan jordtyperna antyder att jordens kemiska och fysiska egenskaper påverkade mikroorganismernas abundans såväl som föroreningarnas biotillgänglighet. PAO minskade med ökande kopparhalt för båda jordtyper, däremot sågs en minskning i PAO med ökande PAH-halt endast i den sura jorden. Resultaten antyder att abundansen av AOA och Nitrospiras verkar ha störst potential att utgöra generella indikatorer över ändrad markfunktion, dock lämpligen med komplettering av förbättrade mätningar av PAO för att få mer information om kvävets kretslopp i förorenad jord. / In Sweden there are around 25,000 contaminated areas classified as a risk for human health or the environment, and even more potentially contaminated areas. The Swedish Environmental Protection Agency has developed generic guideline values for hazardous substances.  Contamination levels exceeding the guideline values indicate a large risk for human health or the environment and that there is a need to remediate the site. A frequently used and expensive aftertreatment is excavation and removal of contaminated soil. Therefore, there is an interest to develop easy applicable methods for site-specific risk assessment with the purpose to protect the soil environment and its functions. Microorganisms involved in the nitrogen cycle perform key functions in soil. Several studies indicate that the abundance and activity of N-cycling microorganisms are sensitive to various soil pollution. Within the research project APPLICERA, a lysimeter experiment was conducted with two different soil types (acidic sandy soil and slightly alkaline sandy loam) and different contamination levels of copper and PAH. The contamination levels corresponded to generic guideline values for sensitive land-use (KM), less sensitive land-use (MKM) and 3xMKM. Soil samples were taken at three times during a period of 16 months. The aim of this master thesis was to investigate nitrifying microorganism potential as indicators for altered soil functioning in contaminated soil. Ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and the nitrite-oxidizing bacteria genera Nitrospira and Nitrobacter has been quantified in soil samples with the different treatments. Measurements of the potential ammonia oxidation (PAO) have been performed in soil from the last sample taking.  The abundance of the nitrifying microorganisms was in general higher in the slightly alkaline sandy loam soil. Over time there was a decrease in AOA abundance for the highest concentration of copper and PAH, most pronounced in the acidic sandy soil. Also, a decrease in the abundance of Nitrospira in soil contaminated with PAHs could be seen for both soil types. In copper contaminated soil a distinct decrease in the abundance of Nitrospira could only be seen in the acidic sandy soil. The abundance of AOB and Nitrobacter did not show any obvious pattern for different contamination levels or over time. The difference in abundance of nitrifying microorganisms between the soil types suggests that the soil’s chemical and physical characteristics as well as the bioavailability of the contaminant affected their abundance. A significant decrease in PAO could be seen for the highest contamination level of copper for both soil types, but for the PAH contaminated soil PAO decreased only in the acidic sandy soil. These results suggest that the abundance of AOA and Nitrospira seems to have greatest potential as general indicators for altered soil functioning. However, improved activity measurements are needed to gain greater insight into the soil N-cycle functioning in contaminated soils.

The new Bluetooth standard (Bluetooth 5.1) contains direction finding specifications. Specifications for received signal strength indicator(RSSI) using measures of signal strength in order to give a sense of how far away an object is has been present in earlier versions. It will now be accompanied with the possibility of angle of arrival estimation(AoA). AoA estimation in Bluetooth utilizes antenna arrays. Antenna arrays are formations of many individual antenna elements working together. The difference between the measured data at each antenna is dependent on the orientation and position of the antenna elements as well as on phase of an incoming electromagnetic signal. By looking at the phase shifts between the antenna elements in an antenna array it is possible to find an estimation of the direction of where the incoming signal is coming from.  The goal of this thesis is to investigate if the NicheTM antenna(concept developed by Proant AB) is applicable for AoA estimation. In the project we have simulated the different characteristics of the Niche antenna and done extensive simulations of different types of configurations of an Niche antenna array. The commercial electromagnetics simulator CST MW studio suite has been used for simulations. A formation that works well with regards to stability and mutual coupling has been found. The simulated results have also been confirmed by measurements on a mechanically constructed antenna array. Measurements have been carried out in an anechoic chamber. We have done full radiation pattern measurements of the antenna array. The antenna array that we have created can estimate the angle of arrival of an incoming signal with an accuracy of 2.7o with a certainty of one standard deviation. For increased accuracy in the AoA estimation a MATLAB code utilizing the MUSIC(MUltiple SIgnal Classification) algorithm with our variant of the steering vector has been written.

The next generation 5G systems has attracted more and more attention to the rapid development of information and communication technology (ICT). Positioning is an important research area in 5G mobile networks, especially in M-MIMO wireless networks. Because the base station needs to have a knowledge of the position of the user equipment, which can direct the signal to the user equipment while reducing interference and hence improve the user throughput. But the problem is that it is difficult to determine position when users are in NLOS scenarios. In the master thesis, we conclude the existing positioning method by the literature review, as well as get the inspiration to design our research environment. Through the MATLAB simulation, we restore the Madrid city three-dimensional environment, design and confirm a new method for the positioning by the AoA and the path power in NLOS scenarios. Our results indicate that the new positioning method demonstrates a nice performance of the accurate level even in the NLOS scenarios, in which the error of the position of the user equipment is within o.5 meters. Although the method is very sensitive to the strange signal paths, we can use the path with the strongest path power to overcome this problem. Meanwhile, the performance of our new positioning method is not impacted by the existence of the scattering loss. / Nästa generations 5G-system har fått mer och mer uppmärksamhet åt den snabba utvecklingen av informations- och kommunikationsteknik (IKT). Positionering är ett viktigt forskningsområde i 5G-mobilnät, särskilt i trådlösa M-MIMO-nätverk. Eftersom basstationen behöver ha kunskap om användarutrustningens position, vilket kan rikta signalen till användarutrustningen samtidigt som störningen minskas och därmed förbättra användarens genomströmning. Men problemet är att det är svårt att bestämma positionen när användare är i NLOS-scenarier. I magisteruppsatsen avslutar vi den befintliga positioneringsmetoden genom litteraturöversikten och får inspiration att designa vår forskningsmiljö. Genom MATLAB-simuleringen återställer vi stadens tredimensionella miljö, designar och bekräftar en ny metod för positionering av AoA och bankraften i NLOS-scenarier. Våra resultat indikerar att den nya positioneringsmetoden visar en bra prestanda för den exakta nivån även i NLOS-scenarierna, där felet i användarutrustningens position ligger inom o.5 meter. Även om metoden är mycket känslig för de konstiga signalvägarna kan vi använda banan med den starkaste vägkraften för att övervinna detta problem. Samtidigt påverkas inte vår nya positioneringsmetod av spridningsförlusten.

There is a high demand for Indoor Positioning Systems (IPS) due to the wide application possibilities. The main issue for localization by wireless signals in an indoor environment is the multipath propagation problem. Multipath propagation occurs when signals reflects and refract from an object, changing the signals characteristics. Today there is no IPS that can balance the cost, accuracy, and complexity. In January 2019 Bluetooth released a new standard, Bluetooth Low Energy (BLE) 5.1, which enables the ability to measure the Angle of Arrival (AoA) of an incoming signal. The purpose of this thesis is to mitigate the disturbances caused by multipath propagation by conducting a case study. This was done by designing systems that combine different positioning techniques with sensor fusion and evaluating them based on power efficiency, execution time and precision. Two wireless localization techniques were evaluated, trilateration and triangulation, which are based on Received Signal Strength Indication (RSSI) and AoA respectively, along with an Inertial Measurement Unit (IMU). An Extended Kalman Filter EKF was used to fuse the sensor data. The system with the best overall performance uses the AoA signals and a multipath mitigation technique. The system with AoA and IMU had a similar performance but has an overall higher complexity due to the added IMU component. The RSSI system could not satisfy the requirement of precision. / Det finns en stor efterfrågan på inomhus positionssystem (IPS) tack vare de många möjliga tillämpningarna. Det största problemet för inomhuslokalisering med trådlösa signaler i inomhusmiljö är flervägsutbredningsproblemet. Felvägsutbredning inträffar när signaler reflekterar och bryts på ett objekt, och ändrar dess karaktär. Idag finns det inga IPS som kan balansera kostnaden, noggrannhetoch komplexitet. I januari 2019, släppte Bluetooth en ny standard, Bluetooth Low Energy (BLE) 5.1, som gör det möjligt att mäta ankomstvinkeln (AoA) för en inkommande signal. Syftet med denna avhandling är att minska störningarna orsakade av flervägsutbredning genom att utföra en fallstudie. Detta gjordes genom att designa system som kombinerar olika positioneringstekniker med sensor fusion och utvärdera dessa med avseende på energieffektivitet, exekveringstid och precision. Två trådlösa lokaliseringstekniker utvärderades, trilaterering och triangulering, som är baserade på mottagen signalstyrka indikation RSSI och AoA respektive, tillsammans med en tröghetssensor (IMU). Ett Utökat Kalman-Filter (EKF) användes för att kombinera data. Systemet med den överlag bästa prestandan använder AoA-signaler och en teknik för att dämpa flervägsutredningen. Systemet med AoA och IMU hade liknande prestanda men den totala komplexiteten ökade med att lägga till en IMU komponent. RSSI systemet var inte tillräckligt tillfredsställande med avseende på precisionskraven.

No description available.

We have implemented a TDOA multilateration of transmitters on an unmodified rtl-sdr receiver using transmitters with known location as a timing reference. We present a brief theoretical background and describe the measurement process which includes several approaches that correct the timing and frequency errors between the receivers. Additionally, we have implemented an angle of arrival direction finder using coherent rtl-sdr.

Submitted by Sandro Camargo (sandro.camargo@unipampa.edu.br) on 2015-05-09T22:47:27Z No. of bitstreams: 1 107110007.pdf: 1654710 bytes, checksum: e686a46dd07db8e06756be03781d37bb (MD5) / Made available in DSpace on 2015-05-09T22:47:27Z (GMT). No. of bitstreams: 1 107110007.pdf: 1654710 bytes, checksum: e686a46dd07db8e06756be03781d37bb (MD5) Previous issue date: 2014 / Atualmente, as tecnologias para comunicações sem fio que utilizam a rádio-frequência estão em ascensão. Um dos motivos é o baixo custo que esta tecnologia atingiu e também a nova gama de aplicações possíveis com a sua utilização. Em particular, destacam-se os sistemas de localização em uma rede de sensores sem fio. Nestes sistemas de localização, métodos especiais são necessários para determinar distância ou ângulo e a localização do objeto de interesse, tendo cada método suas vantagens e desvantagens. Nesta dissertação é desenvolvido um novo sistema de localização em campo aberto de baixo custo utilizando a técnica conhecida como received signal strength indication (RSSI), juntamente com a técnica de medição de ângulo angle of arrival (AoA). Finalmente, um novo método de localização de baixo custo é sugerido: Localização por um Ponto (LpUp). Esta dissertação consta de uma revisão bibliográfica dos métodos de medição de distância, ângulo e localização existentes, simulação, testes em campo, determinação de variáveis de influência do RSSI, algoritmo e firmware do LpUp. Testes em campo indicaram que a acurácia do sistema pode chegar a 0,4 m, dependendo das condições do local e da configuração do LpUp. Devido à redução de custos do LpUp em comparação a outras técnicas de localização, será possível introduzir uma nova gama de aplicações no mercado. / Nowadays, wireless technologies that use radio-frequency are growing, whereby the reason can be attributed to the low cost of this technology and to the possibility of developing several different applications. One of these applications is the localization system in a wireless sensor network. In this work, a low-cost localization method for open-field applications that uses the RSSI technique to estimate distance and angle is presented: Localization by one Point (LboP). This work includes: literature review of the distance, angle and localization methods, simulation, field tests, determination of the RSSI influences on the precision and accuracy of the positioning, algorithm and firmware of the LboP. This new localization system was realized and field tests show that the LboP accuracy can go down to 0,4 m.A limitation of the proposed method is its dependency on the terrain and on the LboP configurations. Due to the cost reduction of the LboP in comparison to other localization systems, new types of applications may be introduced in the market.

Mes travaux traitent essentiellement des marchés financiers incomplets. J'ai choisi de les regrouper en trois parties. La première traite de la caractérisation de l'hypothèse d'absence d'opportunité d'arbitrage et de ses implications en termes d'évaluation. La seconde explore deux pistes possibles pour l'évaluation et la couverture d'actifs dérivés en marché incomplet : la sur-réplication et l'exploitation de la condition de No Good Deal. Enfin, le dernière partie s'intéresse aux comportements limites ainsi qu'à la stabilité des choix optimaux des agents par rapport à des perturbations de leur évaluation du risque. Dans ce contexte, nous nous intéressons aussi à d'autres règles d'évaluation : les prix d'utilités.

Ultra Wideband (UWB) signal can offer an accurate location service in wireless sensor networks because its high range resolution. Target tracking by multiple sensors can provide better performance, but the centralized algorithms are not suitable for wireless sensor networks. In additional, the non line of sight (NLOS) propagation error leads to severe degradation of the accuracy in location systems. In this thesis, NLOS identification and mitigation technique utilizing modified biased Kalman filter (KF) is proposed to reduce the NLOS time of arrival (TOA) errors in UWB environments. We combine the modified biased Kalman filter with sliding window to identify and mitigate different degree of NLOS errors immediately. In order to deal with the influence of inaccurate NLOS angle of arrival (AOA) measurements, we also had a discussion on AOA selection and fusion methods. In the distributed location structure, we used the extended Information filter (EIF) to process the formulated time difference of arrival (TDOA) and AOA measurements for the target positioning and tracking. Instead of using extended Kalman filter, extended Information filter can assimilate selected AOA easily without dynamic dimensions. The sensors are divided into different groups for distributed TDOA/AOA location to reduce computation and then each group can assimilate information from other groups easily to maintain precise location. The simulation results show that the proposed architecture can mitigate NLOS errors effectively and improve the accuracy of target positioning and tracking from distributed location and data fusion in wireless sensor networks.