The demand of wireless communication has increased significantly in the past few decades due to huge demand to deliver multimedia content instantly. The expansion of mobile content paired with affordable mobile devices has opened a new trend for having access to the latest information on mobile devices. This trend is made possible by the technology of smart antenna systems as well as array signal processing algorithms. Array signal processing is not limited to wireless communication, but also found in other applications such as radar, sonar and automotive. One of the important components in array signal processing is its ability to estimate the direction of incoming signals known as directional-of-arrival (DOA). The performance of DOA algorithms depends on the steering vector since it contains information about the direction of incoming signals. One of the main factors to affect the DOA estimation is the array geometries since the array factor of the array geometries determines the definition of the steering vector. Another issue in DOA estimation is that the DOA algorithms are designed based on the ideal assumption that the antenna arrays are free from imperfection conditions. In practice, ideal conditions are extremely difficult to obtain and thus the imperfect conditions will severely degraded the performance of DOA estimation. The imperfect conditions include the presence of mutual coupling between elements and are also characteristic of directional antenna. There are three topics being discussed in this thesis. The first topic being investigated is new geometry of antenna array to improve the performance of DOA estimation. Two variants of the circular-based array are proposed in this thesis: semi-circular array and oval array. Another proposed array is Y-bend array, which is a variant of V-shape array. The proposed arrays are being put forward to offer a better performance of DOA estimation and have less acquired area compared with the circular array. It is found out that the semi-circular array has 5.7% better estimation resolution, 76% lower estimation error, and 20% higher estimation consistency than the circular array. The oval array improves the estimation resolution by 33%, estimation error by 60%, and estimation consistency by 20% compared with the circular array. In addition, for the same number of elements, the oval array requires 12.5% to 15% less area than the circular array. The third proposed array, Y-bend array, has 23% smaller estimation resolution, 88% lower estimation error, and 7% higher estimation consistency than the V-shape array. Among the proposed arrays, the semi-circular possessed the best performance with 25% smaller estimation resolution, ten times smaller estimation error, and 5% higher estimation consistency over the other proposed arrays. Secondly, this thesis investigates the DOA estimation algorithm when using the directional antenna array. In this case, a new algorithm is proposed in order to suit the characteristics of the directional antenna array. The proposed algorithm is a modified version of the Capon algorithm, one of the algorithms in beamforming category. In elevation angle estimation, the proposed algorithm achieves estimation resolution up to 1°. The proposed algorithm also manages to improve the estimation error by 80% and estimation consistency by 10% compared with the Capon algorithm. In azimuth angle estimation, the proposed algorithm achieves 20 times lower estimation error and 20% higher estimation consistency than the Capon algorithm. These simulation results show that the proposed algorithm works effectively with the directional antenna array. Finally, the thesis proposes a new method in DOA estimation process for directional antenna array. The proposed method is achieved by means of modifying covariance matrix calculation. Simulation results suggest that the proposed method improves the estimation resolution by 5° and the estimation error by 10% compared with the conventional method. In summary, this thesis has contributed in three main topics related to DOA estimation; array geometry design, algorithm for the directional antenna array, and method in DOA estimation process for the directional antenna array.

Submitted by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-06-29T12:10:17Z No. of bitstreams: 1 PriscilaOliveiradeCarvalhoDissertacao2016.pdf: 1087048 bytes, checksum: 5a55853073d91c89f9f3984e3aab2fb7 (MD5) / Approved for entry into archive by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-06-29T12:11:03Z (GMT) No. of bitstreams: 1 PriscilaOliveiradeCarvalhoDissertacao2016.pdf: 1087048 bytes, checksum: 5a55853073d91c89f9f3984e3aab2fb7 (MD5) / Made available in DSpace on 2017-06-29T12:11:03Z (GMT). No. of bitstreams: 1 PriscilaOliveiradeCarvalhoDissertacao2016.pdf: 1087048 bytes, checksum: 5a55853073d91c89f9f3984e3aab2fb7 (MD5) Previous issue date: 2016-08-15 / The increase in demand for blood from issues such as violence, traffic accidents, increasing aging population, advances in medical technology and also the existence of policies that adopt more rigorous for clinical screening of candidates for blood donation, can impact on maintenance blood stocks in the country. With the expansion of the candidate's age to donate blood up to 69 years, the elderly has become a potential contributor of transfusion services. In this research, it was made a retrospective, comparative, descriptive, quantitative, based on the analysis of existing secondary data in the computerized system of the Blood Center of Health System of the Federal District. From notes inserted by the health team in the electronic records were verified in the period January to December 2014, the records of adverse reactions submitted to blood donation of 214 elderly donors, aged 60-69 years and 357 mature adults, aged 50-59 years. They checked the prevalence of adverse reactions to the elderly blood donation as the intensity and compared with a group of mature donors (50-59 years). Among the elderly, the prevalent adverse reactions (3.27%) were classified as mild: low flow (2.33%) and venous inaccessibility (0.93%). In the group 50-59 years had clinical manifestations beyond mild reactions: low flow (2.24%), hematoma (0.28%), venous inaccessibility (0.84%) 3 and sweating (0.28%). It was also observed moderate type of reaction: convulsion (0.28%). The results point to a deficit in the notes of adverse events to the donation by the health team from the records of donors. There is need to implement strategies in the country to reach the elderly donors, as well as a review of the safety criteria for blood donation in this age group. / O aumento nas demandas por sangue a partir de quest??es como viol??ncia, acidentes de tr??nsito, crescente envelhecimento populacional e ainda a exist??ncia de pol??ticas que adotam maior rigor para triagem cl??nica dos candidatos ?? doa????o de sangue podem impactar na manuten????o de estoques de sangue no pa??s. Com a amplia????o da faixa et??ria do candidato ?? doa????o de sangue at?? os 69 anos, o idoso tornou-se um potencial colaborador dos servi??os de hemoterapia. Nesta pesquisa foi feito um estudo retrospectivo, comparativo e descritivo, de ordem quantitativa, a partir da an??lise de dados secund??rios existentes no sistema informatizado de um Hemocentro do Sistema ??nico de Sa??de do Distrito Federal. A partir de anota????es inseridas pela equipe de sa??de nos prontu??rios eletr??nicos verificados, no per??odo de janeiro a dezembro de 2014, os registros de rea????es adversas apresentadas ?? doa????o de sangue de 214 doadores idosos, com idade de 60 a 69 anos e 357 adultos maduros, com idade de 50 a 59 anos. Foram verificados ?? preval??ncia das rea????es adversas ?? doa????o de sangue de idosos quanto ?? intensidade e comparado com um grupo de doadores maduros (50 a 59 anos). Entre os idosos, as rea????es adversas prevalentes (3,27%) foram as classificadas como de grau leve: baixo fluxo (2,33%) e inacessibilidade venosa (0,93%). J?? no grupo de 50 a 59 anos apresentaram manifesta????es cl??nicas al??m das rea????es leves: baixo fluxo (2,24%), hematoma (0,28%), inacessibilidade venosa (0,84%) e sudorese (0,28%). Tamb??m foi observada tipo moderado de rea????o: convuls??o (0,28%). Os resultados apontam para um d??ficit nas anota????es dos eventos adversos ?? doa????o por parte da equipe de sa??de nos prontu??rios dos doadores. H?? necessidade de implanta????o de estrat??gias no pa??s para alcan??ar os doadores idosos, assim como revis??o dos crit??rios de seguran??a para doa????o de sangue neste grupo et??rio.

La recherche en matière de sécurité automobile est en pleine expansion, notamment l'addition de radar anti-collision va permettre de mesurer la distance et la vitesse des obstacles.Notre étude porte sur un radar de type Duplex, constitué d'un réflectomètre "six-port". Le principe consiste à envoyer deux signaux hyperfréquences continus avec un faible écart fréquentiel. Par mélange des signaux reçus et émis, on trouve deux signaux Doppler approximativement de même fréquence mais avec une différence de phase. La mesure de celle-ci nous permet de déterminer la distance de l'obstacle. La vitesse relative sera calculée à partir de la fréquence Doppler d'un des signaux.Une simulation complète de notre système sous MATLAB est présentée. Cette simulation nous a permis d'étudier l'influence du rapport signal à bruit et de la phase de l'oscillateur local sur les performances du radar.Une validation expérimentale de cette étude à 2GHz, a été réalisée dans notre laboratoire par la mesure de la distance et de la vitesse d'une cible. Nous nous sommes également intéressés à la détection de la direction d'arrivée des signaux réfléchis par la cible. Nous présentons l'étude, la simulation et la mesure de celle-ci, ainsi que l'étude et la réalisation d'un réseau d'antennes patch. La détermination de cette direction d'arrivée a été faite en utilisant un réseau de circuits réflectomètres "five-port" ainsi que le réseau d'antennes patch, avec l'aide de l'algorithme MUSIC (Multiple Signal Classification). Finalement, nous étudions l'influence du bruit sur le système de détection de direction d'arrivée.

No description available.

Sensor arrays are used in many applications where their ability to localize signal sources is essential. For many applications, it is necessary to estimate the direction-of-arrival (DOA) of target sources. Although there are many DOA estimation methods available, most of them are valid only for narrowband signals where time delay can be approximated as a phase shift. This thesis focuses on DOA estimation algorithms for wideband sources. Specifically, this thesis proposes the pruned fast beamformer which can reduce the number of computations of Delay-and-Sum (DS) beamforming by using a multi-resolution structure. For high resolution methods, signal subspace methods are required. Most of the subspace techniques for wideband signals decompose the received wideband signals into several bands of narrowband signals through bandpass filtering. Then, there are two different ways of processing decomposed signals. The incoherent methods process each band independently by a given narrowband method and average the results. The coherent methods attempt to modulate the signals in each band so that they can be combined coherently. In this thesis, a new DOA estimator, which is called TOPS, is developed to avoid disadvantages of both the incoherent and the coherent methods. The new method which can be categorized as a non-coherent method is tested and compared with other methods. It exhibits many desirable features for a number of applications where the sources are wideband such as acoustic direction finding.

In this dissertation, we design and develop a novel direction-of-arrival (DOA) finding system. We investigate the problems of DOA finding using canonical and crystallographic antenna array structures, develop a novel integrated algorithm consisting of combined multiple signal classification (MUSIC) algorithm, Kalman Filter and Kent Distribution to improve the accuracy and robustness of DOA estimation, design and conduct the real time testing of DOA and verify the accuracy and efficiency of the designed DOA finding system. We first examine the ability of mitigating the aliasing and enhancing the DOA estimation of different antenna structures, including canonical and crystallographic antenna structures. Our results show that the crystallographic antenna array has a better performance of overcoming aliasing in many circumstances, improving the estimation accuracy and covering more spatial region of DOA estimation. Then we propose a novel integrated algorithm to achieve a more robust DOA finding with higher accuracy. We show that the DOA estimation using MUSIC algorithm can be strongly influenced by the size, spacing and distributions of elements of the receiving antenna array as well as noise and mutual coupling. We propose a combined MUSIC and Kalman Filter algorithm to reduce the noise and enhance the robustness of the DOA estimation. Further more we map the DOA estimation onto the sphere and use Kent distribution to characterize the spread of DOA points on the sphere. We calculate the mean direction of Kent distribution to present the DOA vector, which further improves the accuracy of DOA finding. At last, we design and build a multi-channel and real time automated measurement system to validate the proposed antenna structure and integrated algorithms. Our testing results indicate that the designed DOA finding system can work practically and efficiently, with higher accuracy and stronger robustness.

Position information is important for various applications, including location-aware communications, autonomous driving, industrial internet of things (IoT). Geometry based techniques such as time-of-arrival (TOA), time-difference-of-arrival (TDOA), and angle-of-arrival (AOA) are widely used and can be formed as optimization prob lems. In order to solve these optimization problems efficiently, stochastic optimization methods are discussed in this work in solving target positioning problems and tackling key issues in location-based applications. Firstly, the direction of arrival (DOA) estimation problem is studied in this work. Grid search is useful in the algorithms such as maximum likelihood estimator (MLE), MUltiple SIgnal Classification (MUSIC), etc. However, the computational cost is the main drawback. To speed up the search procedure, we implement random ferns to extract the features from the beampatterns of different DOAs and use these features to identify potential angle candidates. Then, we propose an ultrasonic air-writing system based on DOA estimation. In this application, stochastic optimization methods are implemented to solve gesture classification problems. This work shows that stochastic optimization methods are effective tools to address and benchmark practical positioning-related problems. Next, we discuss how to select antennas properly to reduce the expectation of DOA estimation error in a switch-based multiple-input-multiple-output (MIMO) system. Cram`er Rao lower bound (CRLB) expresses a lower bound on the variance of an unbiased estimator, but it does not work well for low SNR scenarios. We use DOA threshold-region approximation as an indicator and propose a greedy algorithm and a neural network-based algorithm. Finally, we propose a joint time difference of arrival (TDOA) and phase difference of arrival (PDOA) localization method. It is shown that the phase difference, which is also widely used in DOA estimation, can improve the performance of the well established TDOA technique. Although the joint TDOA/PDOA cost function has a lot of local minima, accurate estimates can be obtained effectively by choosing an appropriate initial estimation and using particle swarm optimization (PSO).

No description available.

The objective of this thesis is to design, build and evaluate a direction-of-arrival measurement system using an antenna array operating at 2050 MHz. The first phase of the project is an extensive study of various high resolution DOA estimation algorithms. The algorithms studied include subspace-based techniques such as the MUSIC (MUltiple Signal Classification) and ESPRIT (Estimation of Signal Parameters via Rotational Invariance) algorithm, and the integrated approaches which combine property restoral-based techniques such as the Iterative Least Squares Projection-based Constant Modulus Algorithm (lLSP-CMA) with subspace-based techniques. All these algorithms were simulated in MATLAB and their performance under different conditions were tested and compared. In the second phase of the project a six element uniformly spaced linear array receiver was built. Three Ariel DSP-96 boards based on the Motorola DSP96002 are used to simultaneously sample, collect, and store data from each of the array elements. The data collected by the DSP boards are processed off-line to estimate the directions of arrival. Several experiments are conducted to test the functioning of the system under various conditions, and demonstrate the performance of different algorithms. Results of these experiments are also presented in this thesis. / Master of Science

We have created an eight-element antenna array system for evaluating various Angle of Arrival (AOA) Position Location (PL) algorithms, such as MUltiple SIgnal Classification (MUSIC) and Estimation of Signal Parameters via Rotational Invariance Techniques ESPRIT algorithms. Since using delay of arrival information can improve AOA estimates and classical PL algorithms do not incorporate Delay of Arrival (DOA) information, the performance of these algorithms is not optimal. Recently proposed Joint AOA and DOA Estimation (JADE) algorithms, though more complicated, potentially have higher resolutions in both space and time domains. Our investigation shows that by using bandlimited known signals it is possible to resolve the DOA within a fraction of the sample period using JADE algorithms. Joint AOA and DOA algorithms can provide high resolution DSP-based channel measurement using low bandwidth hardware. / Master of Science