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Identification and Modeling of the Dynamic Behavior of the Direct Path Component in ToA-Based Indoor Localization SystemsHeidari, Mohammad 15 July 2008 (has links)
"A well-known challenge in estimating the distance of the antenna pair in time-of-arrival (ToA) based RF localization systems is the problem of obstruction of the direct path (DP) between transmitter and receiver. The absence of DP component in received channel profile creates undetected direct path (UDP) conditions. UDP condition, in turn, will cause occurrence of unexpected large ranging errors which pose serious challenge to precise indoor localization. Analysis of the behavior of the ranging error in such conditions is essential for the design of precise ToA-based indoor localization systems. This dissertation discusses two open problems in ToA-based indoor localization systems. The first contribution of this dissertation discusses the problem of modeling of dynamic behavior of ranging error. We propose a novel analytical framework for analysis of dynamic spatial variations of ranging error observed by a mobile user based on an application of Markov chain. The model relegates the behavior of ranging error into four main categories associated with four states of Markov process. Parameters of distributions of ranging error in each Markov state are extracted from empirical data collected from a measurement-calibrated ray tracing algorithm simulating a typical office environment. The analytical derivation of parameters of the Markov model employs the existing path-loss models for first detected path and total multipath received power in the same office environment. Results of simulated errors from the Markov model and actual errors from empirical data show close agreement. The second contribution of this dissertation discusses the problem of identification of UDP condition given an unknown channel profile. Existing of UDP condition in a channel profile poses serious degradation to ranging estimate process. Therefore, identification of occurrence of UDP condition is of our subsequent concern. After identification, the second step is to mitigate ranging errors in such conditions. In this dissertation we present two methodologies, based on binary hypothesis testing and an application of artificial neural network design, to identify UDP conditions and mitigate ranging error using statistics extracted from wideband frequency-domain indoor measurements conducted in typical office building. "
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Measurement of TOA Using Frequency Domain Techniques for Indoor GeolocationZand, Emad Dolatshahi 28 April 2003 (has links)
Frequency domain techniques have been widely used in indoor radio propagation measurements and modeling for telecommunication applications. This work addresses measurement of the time of arrival (TOA) of the first path for geolocation applications using results of frequency domain channel measurements. First, we analyze the effect upon TOA measurement accuracy due to: sampling period of the radio channel in the frequency domain, sampling period in the time domain used for detection of the TOA and the windowing filter used before transformation to the time domain. Then, we provide some results of measurement made in line of sight (LOS) and Obstructed LOS (OLOS) indoor environments in order to compare the characteristics of the measured TOA in these two important scenarios for indoor geolocation applications. Finally, we compare the measurement results with the ray tracing based model that had been developed previously for indoor geolocation applications.
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UWB Motion and Micro-Gesture Detection -Applications to interactive electronic gaming and remote sensingZang, Yuzhang 03 May 2016 (has links)
The ultra-wideband (UWB) technology has a vast unlicensed frequency spectrum, which can support precise indoor positioning in orders of centimeters. The features of UWB signals can be utilized for variety of applications. In this project first we present an empirical channel models to analyze the localization accuracy of the UWB technology for interactive electronic gaming (Ping-Pong) in Line-of-Sight (LOS) and Obstructed LOS (OLOS) scenarios. Then we introduce a new concept that we refer to as micro-gesture detection to handle the more refined motions of the hand, such as rotation, while one antenna is held by the user using features of UWB signal. We use four specific features of the UWB signals: time of arrival, power of the first peak, total power, and the Root-Mean Square (RMS) of the delay spread, for this purpose. As the hand rotates the position of the antenna in the hand and the external antenna changes from LOS to OLOS. We demonstrate that features of the UWB signals are more useful than the RSS signal of the Wi-Fi to detect this class of micro-gestures. We foresee this micro-gesture detection capabilities become helpful for the people with limited ability or visually impaired for implementation of simplified sign language to communication with electronic devices located away from a person. We compare gesture detection using multiple features of the UWB signal with traditional gesture detection using the received signal strength (RSS) of the Wi-Fi signal.
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TOA-Based Robust Wireless Geolocation and Cramér-Rao Lower Bound Analysis in Harsh LOS/NLOS EnvironmentsYin, Feng, Fritsche, Carsten, Gustafsson, Fredrik, Zoubir, Abdelhak M January 2013 (has links)
We consider time-of-arrival based robust geolocation in harsh line-of-sight/non-line-of-sight environments. Herein, we assume the probability density function (PDF) of the measurement error to be completely unknown and develop an iterative algorithm for robust position estimation. The iterative algorithm alternates between a PDF estimation step, which approximates the exact measurement error PDF (albeit unknown) under the current parameter estimate via adaptive kernel density estimation, and a parameter estimation step, which resolves a position estimate from the approximate log-likelihood function via a quasi-Newton method. Unless the convergence condition is satisfied, the resolved position estimate is then used to refine the PDF estimation in the next iteration. We also present the best achievable geolocation accuracy in terms of the Cramér-Rao lower bound. Various simulations have been conducted in both real-world and simulated scenarios. When the number of received range measurements is large, the new proposed position estimator attains the performance of the maximum likelihood estimator (MLE). When the number of range measurements is small, it deviates from the MLE, but still outperforms several salient robust estimators in terms of geolocation accuracy, which comes at the cost of higher computational complexity.
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Comparison and implementation of IPSHelgesson, Dan, Nilsson, Emelie January 2014 (has links)
Innomhuspositioneringssystem kan med fördel användas i många olika tillämpningar, allt från sjukhus till shoppingcenter. Denna rapport behandlar olika tekniker och lösningar för att designa ett positioneringssystem. Rapporten tar även upp i detalj hur ett system kan konstrueras av ZigBee kombinerat med dödräkning.
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Localization algorithms for passive sensor networksIsmailova, Darya 23 January 2017 (has links)
Locating a radiating source based on range or range measurements obtained from a network of passive sensors has been a subject of research over the past two decades due to the problem’s importance in applications in wireless communications, surveillance, navigation, geosciences, and several other fields. In this thesis, we develop new solution methods for the problem of localizing a single radiating source based on range and range-difference measurements. Iterative re-weighting algorithms are developed for both range-based and range-difference-based least squares localization. Then we propose a penalty convex-concave procedure for finding an approximate solution to nonlinear least squares problems that are related to the range measurements. Finally, the sequential convex relaxation procedures are proposed to obtain the nonlinear least squares estimate of source coordinates. Localization in wireless sensor network, where the RF signals are used to derive the ranging measurements, is the primary application area of this work. However, the solution methods proposed are general and could be applied to range and range-difference measurements derived from other types of signals. / Graduate / 0544 / ismailds@uvic.ca
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Etude des antiprotons d'origine atmospherique au voisinage de la TerreHuang, Ching-Yuan 14 May 2002 (has links) (PDF)
Cette these a pour objet l'etude de la production d'antiproton dans l'atmosphere. Une parametrisation de la section efficace inclusive pour la production d'antiprotons dans les collisions p+p et p+A est presentee, basee sur les regles de comptage de quarks, la phenomenologie de Regge et l'ajustement aux donnees. Cette parametrisation est en accord avec les donnees experimentales pour une energie incidente du nucleon au moins jusqu'a 24 GeV/n dans le laboratoire. Selon l'analyse de la distribution de la multiplicite moyenne d'antiprotons, cette parametrisation peut etre etendue sa validite jusqu'au moins s^1/2 environ 25 GeV dans le centre de masse. Avec cette parametrisation, le modele des nucleons touches est applique pour obtenir la section efficace de production d'antiprotons lors d'une collision A+A. Le flux atmospherique d'antiprotons aux altitudes des ballons et des satellites est calcule en incluant les protons et heliums cosmiques. Les collisions generees par l'helium contribuent pour environ 30% au flux total d'antiprotons atmospherique. Pour l'etude de l'origine exotique d'antiprotons, par exemple l'annihilation de la matiere sombre supersymetrique (les neutralinos) et l'evaporation des trous noirs primordiaux, les energies incidentes des particules cosmiques jusqu'a E=200 GeV/n contribuent le plus magnifiquement a la production d'antiprotons atmospheriques. Il est montre que le flux atmospherique d'antiprotons utilise pour corriger le flux d'antiprotons au dessus de l'atmosphere est sous-estime dans certains travaux precedents. Dans ce travail, le flux d'antiprotons au dessus de l'atmosphere est donc diminue de 10-15% par rapport au resultat original dans le domaine d'energie E_k> 1 GeV. Une experience de mesure d'antiprotons au sol est proposee pour valider la justesse de la production d'antiprotons calcules par les differents groupes. Les resultats de l'experience BESS 1999 a l'altitude de 2.77 km ont confirme la justesse de ce travail. A l'altitude d'AMS, le flux d'antiprotons mesure par cette experience dans la region polaire est pratiquement exclusivement constitue d'antiprotons cosmiques, avec une composante de seulement 2-3% d'antiprotons atmospheriques. Il est observe que, meme a tres haute altitude, quelques milliers de kilometres par exemple, il existe encore un flux residuel d'antiprotons atmospheriques dont les trajectoires sont tres compliquees et ne peuvent pas etre bien expliquees au moyen des variables habituelles. Finalement, le flux atmospherique de protons dans l'atmosphere est calcule. La deviation entre les calculs et les donnees ainsi que les origines possibles de cette deviation sont discutees.
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Pacific Northwest rangeland carbon sequestrationWiggins, Seth T. 01 June 2012 (has links)
This paper models the supply curve of carbon sequestration on Pacific Northwest rangelands. Rangeland managers have the ability to sequester carbon in agricultural soils by implementing alternative management practices on their farms. Their low adoption rate in practice suggests a high opportunity cost associated with their implementation. To increase their adoption, a payment for ecosystem services plan is proposed, where the public compensates farms for lost profits. The TOA-MD model is used to estimate the resulting sequestration incentivized by payments for soil carbon sequestration. Methodological questions of geographical stratification and estimating variation from available data are tested. Sensitivity analysis is also run on key assumptions in the study. Results show that while the economic potential of both systems is much lower than the technical potential, at reasonable CO��� payment levels rangeland sequestration could be a significant mitigation strategy for Pacific Northwest states. / Graduation date: 2012
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Real Time Positioning; Construction and implementation of a GPS-Communicator. / Realtidspositionering; Utveckling av en GPS-kommunikator.Darnell, Christian, Wilczoch, Christian January 2002 (has links)
The first half of the Masters thesis is the result of a survey made on the behalf of the Swedish company KORDAB International AB. The survey includes an overview of different positioning systems and some wireless communication techniques available on the market today. Positioning systems discussed are GPS, DGPS, AGPS and GSM positioning. Mobile Internet connections through mobile phones and communication through radio modems are mentioned and described as examples of wireless communication techniques. Examples of techniques described are HSCSD, GPRS, UMTS and MOBITEX. KORDAB is in the starting blocks to implement a real time positioning feature into their own technical information system GEOSECMA. This survey will give them a base which will help them to decide on which system to use for this feature. The second half of the thesis includes parts concerning a prototype made to exemplify how KORDAB could implement the real time positioning feature into GEOSECMA. The NMEA 0183 protocol, reference systems and transformation are described to give the necessary background knowledge for the construction and functionality of the prototype. The prototype is a GPS-communicator made as an interface between a GPS-receiver and GEOSECMA and its functionality is also described in this second half of the thesis. Feasible applications are also discussed to show the possibilities real time positioning gives. One application discussed is “Zoom and Auto highlighting”. This application is designed to help user of GEOSECMA to zoom in the map and highlighting the nearest object at current location.
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Real Time Positioning; Construction and implementation of a GPS-Communicator. / Realtidspositionering; Utveckling av en GPS-kommunikator.Darnell, Christian, Wilczoch, Christian January 2002 (has links)
<p>The first half of the Masters thesis is the result of a survey made on the behalf of the Swedish company KORDAB International AB. The survey includes an overview of different positioning systems and some wireless communication techniques available on the market today. Positioning systems discussed are GPS, DGPS, AGPS and GSM positioning. Mobile Internet connections through mobile phones and communication through radio modems are mentioned and described as examples of wireless communication techniques. Examples of techniques described are HSCSD, GPRS, UMTS and MOBITEX. KORDAB is in the starting blocks to implement a real time positioning feature into their own technical information system GEOSECMA. This survey will give them a base which will help them to decide on which system to use for this feature. </p><p>The second half of the thesis includes parts concerning a prototype made to exemplify how KORDAB could implement the real time positioning feature into GEOSECMA. The NMEA 0183 protocol, reference systems and transformation are described to give the necessary background knowledge for the construction and functionality of the prototype. The prototype is a GPS-communicator made as an interface between a GPS-receiver and GEOSECMA and its functionality is also described in this second half of the thesis. Feasible applications are also discussed to show the possibilities real time positioning gives. One application discussed is “Zoom and Auto highlighting”. This application is designed to help user of GEOSECMA to zoom in the map and highlighting the nearest object at current location.</p>
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