• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 2
  • 2
  • 2
  • Tagged with
  • 11
  • 11
  • 11
  • 4
  • 4
  • 4
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A PARALLEL -SEQUENTIAL SEARCH ALGORITHM IN A HIGH DYNAMIC GPS RECEIVER

Xingyu, Luo, Qishan, Zhang 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / It is need to design acquisition and tracking for code loop and carrier loop to detect the high dynamic Global Position System (GPS) signal. Acquiring signal quickly and shortening acquisition time in the cold case are key technology of a high dynamic GPS receiver. Moreover, fast acquisition of C/A code is the base of code tracking and carrier acquisition and tracking. This paper describes elements and implementation of a new parallel-sequential search Algorithm to acquire C/A code of the high dynamic GPS signal. And combined with a 12-channel correlator named GP2021 produced by GEC Co., the arithmetic implementation to acquire C/A code of the high dynamic GPS signal used sequential search based on DSP technology is also given.
2

DESIGN OF A HIGH DYNAMIC GPS RECEIVER

Bochuan, Zhang, Yanhong, Kou, Qishan, Zhang, Qing, Chang 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / High dynamic and multi-channel digital GPS receiver can handle the signals with high dynamic range, low S/N ratio and refresh data quickly. A hardware design of high dynamic GPS digital receiver is given. Based on analysis of the effect that high dynamic movement makes on the receiving signals, a scheme of fast-acquisition high dynamic GPS receiver is presented. Exact reckoning of the orbit parameters and the satellite clock parameters are integrated with appropriate algorithms. A DDLL is used to precisely estimate the C/A code delay, a CPAFC loop and a Costas loop to precisely estimate the carrier frequency and phase. The DDLL is assisted with carrier phase. The experimental results show that the receiver meets the design request.
3

Innovative location based scheme for Internet Security Protocol : a proposed location based scheme N-Kerberos Security Protocol using intelligent logic of believes, particularly by modified BAN logic

Abdelmajid, Nabih T. January 2010 (has links)
The importance of the data authentication has resulted in the science of the data protection. Interest in this knowledge has been growing due to the increase in privacy of the user's identity, especially after the widespread use of online transactions. Many security techniques are available to maintain the privacy of the user's identity. These include password, smart card or token and face recognition or finger print. But unfortunately, the possibility to duplicate the identity of a user is still possible. Recently, specialists used the user's physical location as a new factor in order to increase the strength of the verification of the user's identity. This thesis focused on the authentication-based user's location. It is based on the idea of using the Global Position System in order to verify the user identity. Improving Kerberos protocol using GPS signal is proposed in order to eliminate the effect of replay attack. This proposal does not expect a high performance from the user during the implementation of the security system. Moreover, to give users more confidence to use security protocol, it has to be evaluated before accepting it. Thus, a measurement tool used to validate protocols called BAN logic was described. In this thesis, a new form of BAN logic which aims to raise the efficiency checking process of the protocol protection strength using the GPS signal is proposed. The proposed form of Kerberos protocol has been analysed using the new form of BAN logic. The new scheme has been tested and compared with the existing techniques to demonstrate its merits and capabilities.
4

Multi-Sensor Data Fusion for Vehicular Navigation Applications

Iqbal, Umar 08 August 2012 (has links)
Global position system (GPS) is widely used in land vehicles but suffers deterioration in its accuracy in urban canyons; mostly due to satellite signal blockage and signal multipath. To obtain accurate, reliable, and continuous positioning solutions, GPS is usually augmented with inertial sensors, including accelerometers and gyroscopes to monitor both translational and rotational motions of a moving vehicle. Due to space and cost requirements, micro-electro-mechanical-system (MEMS) inertial sensors, which are typically inexpensive are presently utilized in land vehicles for various reasons and can be used for integration with GPS for navigation purposes. Kalman filtering (KF) usually used to performs this integration. However, the complex error characteristics of these MEMS based sensors lead to divergence of the positioning solution. Furthermore, the residual GPS pseudorange correlated errors are always ignored, thus reducing the GPS overall positioning accuracy. This thesis targets enhancing the performance of integrated MEMS based INS/GPS navigation systems through exploring new non-linear modelling approaches that can deal with the non-linear and correlated parts of INS and GPS errors. The research approach in this thesis relies on reduced inertial sensor systems (RISS) incorporating single axis gyroscope, vehicle odometer, and accelerometers is considered for the integration with GPS in one of two schemes; either loosely-coupled where GPS position and velocity are used for the integration or tightly-coupled where GPS pseudorange and pseudorange rates are utilized. A new method based on parallel cascade identification (PCI) is developed in this research to enhance the performance of KF by modelling azimuth errors for the RISS/GPS loosely-coupled integration scheme. In addition, PCI is also utilized for the modelling of residual GPS pseudorange correlated errors. This thesis develops a method to augment a PCI – based model of GPS pseudorange correlated errors to a tightly-coupled KF. In order to take full advantage of the PCI based models, this thesis explores the Particle filter (PF) as a non-linear integration scheme that is capable of accommodating the arbitrary sensor characteristics, motion dynamics, and noise distributions. The performance of the proposed methods is examined through several road test experiments in land vehicles involving different types of inertial sensors and GPS receivers. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2012-07-31 16:09:16.559
5

Innovative Location Based Scheme for Internet Security Protocol. A proposed Location Based Scheme N-Kerberos Security Protocol Using Intelligent Logic of Believes, Particularly by Modified BAN Logic.

Abdelmajid, Nabih T. January 2010 (has links)
The importance of the data authentication has resulted in the science of the data protection. Interest in this knowledge has been growing due to the increase in privacy of the user's identity, especially after the widespread use of online transactions. Many security techniques are available to maintain the privacy of the user's identity. These include password, smart card or token and face recognition or finger print. But unfortunately, the possibility to duplicate the identity of a user is still possible. Recently, specialists used the user's physical location as a new factor in order to increase the strength of the verification of the user's identity. This thesis focused on the authentication-based user's location. It is based on the idea of using the Global Position System in order to verify the user identity. Improving Kerberos protocol using GPS signal is proposed in order to eliminate the effect of replay attack. This proposal does not expect a high performance from the user during the implementation of the security system. Moreover, to give users more confidence to use security protocol, it has to be evaluated before accepting it. Thus, a measurement tool used to validate protocols called BAN logic was described. In this thesis, a new form of BAN logic which aims to raise the efficiency checking process of the protocol protection strength using the GPS signal is proposed. The proposed form of Kerberos protocol has been analysed using the new form of BAN logic. The new scheme has been tested and compared with the existing techniques to demonstrate its merits and capabilities.
6

Compatibilização de dados, em diferentes referenciais, para atualização cartográfica: estudo de caso na SABESP. / Data transformation for cartographic updating: study of case in SABESP.

Oliveira, Marcos Almir de 27 November 2006 (has links)
Um dos propósitos deste trabalho foi apresentar a metodologia envolvida na estimação de parâmetros de transformação entre dois Sistemas Geodésicos, em função da implantação do Sistema de Informações Geográficas no Saneamento (SIGNOS) pela SABESP. Este estudo foi desenvolvido no Município de São Paulo, onde foram calculados parâmetros de transformação entre os Sistemas SAD-69 (South American Datum 1969) e Córrego Alegre. Os parâmetros obtidos neste estudo foram comparados com os parâmetros disponíveis atualmente. Outro estudo, deste trabalho, é a proposta para compatibilização do sistema altimétrico da SABESP. O sistema atual é formado por diversas redes altimétricas (IBGE, SABESP, EMPLASA e IGG) que são divergentes entre si. O objetivo final é verificar as diferenças regionais e estabelecer a unificação do sistema altimétrico da SABESP na Região Metropolitana de São Paulo (RMSP). / One of the purposes of this work was introduce the methodology involved in the estimate of the transformation parameters between two Geodetic Systems, in function of the implantation of the Geographical Information System by SABESP. This work has been developed in São Paulo City, where transformation parameters were calculated between systems SAD-69 (South American Datum 1969) and Córrego Alegre. The estimated parameters at this work had been compared with the available parameters nowadays. Another study, of this work, is the proposal for compatibility of the altimetric system of SABESP. The current system is formed by diverse altimetric nets (IBGE, SABESP, EMPLASA and IGG) that are divergent between themselves. The final objective is to verify the regional differences and to establish the unification of the altimetric system in São Paulo Metropolitan Region (RMSP).
7

Compatibilização de dados, em diferentes referenciais, para atualização cartográfica: estudo de caso na SABESP. / Data transformation for cartographic updating: study of case in SABESP.

Marcos Almir de Oliveira 27 November 2006 (has links)
Um dos propósitos deste trabalho foi apresentar a metodologia envolvida na estimação de parâmetros de transformação entre dois Sistemas Geodésicos, em função da implantação do Sistema de Informações Geográficas no Saneamento (SIGNOS) pela SABESP. Este estudo foi desenvolvido no Município de São Paulo, onde foram calculados parâmetros de transformação entre os Sistemas SAD-69 (South American Datum 1969) e Córrego Alegre. Os parâmetros obtidos neste estudo foram comparados com os parâmetros disponíveis atualmente. Outro estudo, deste trabalho, é a proposta para compatibilização do sistema altimétrico da SABESP. O sistema atual é formado por diversas redes altimétricas (IBGE, SABESP, EMPLASA e IGG) que são divergentes entre si. O objetivo final é verificar as diferenças regionais e estabelecer a unificação do sistema altimétrico da SABESP na Região Metropolitana de São Paulo (RMSP). / One of the purposes of this work was introduce the methodology involved in the estimate of the transformation parameters between two Geodetic Systems, in function of the implantation of the Geographical Information System by SABESP. This work has been developed in São Paulo City, where transformation parameters were calculated between systems SAD-69 (South American Datum 1969) and Córrego Alegre. The estimated parameters at this work had been compared with the available parameters nowadays. Another study, of this work, is the proposal for compatibility of the altimetric system of SABESP. The current system is formed by diverse altimetric nets (IBGE, SABESP, EMPLASA and IGG) that are divergent between themselves. The final objective is to verify the regional differences and to establish the unification of the altimetric system in São Paulo Metropolitan Region (RMSP).
8

Estudos sobre desempenho de sistemas de piloto automático em tratores / Studies of auto-guidance systems performance in tractors

Oliveira, Tiago Carletti Antunes de 09 October 2009 (has links)
Para o cenário da sustentabilidade da cana um dos problemas é o tráfego indiscriminado de rodados sobre as soqueiras, especialmente na colheita mecanizada, devido a desalinhamentos das fileiras de cana e dificuldade de manutenção dos veículos e composições devidamente afastados destas. Assim, as tecnologias de direcionamento automático estão ganhando espaço no setor sucroalcooleiro. No cenário da citricultura a implantação de um pomar é uma etapa de extrema importância econômica, uma vez que estão envolvidas diversas operações mecanizadas. O alinhamento das fileiras é feito manualmente, etapa que demanda a utilização de uma equipe composta por um topógrafo e cerca de 8 a 10 funcionários. A utilização de sistema de direcionamento automático (piloto automático) elimina esta operação consequentemente reduzindo o número de funcionários. A partir disso o objetivo desse trabalho foi avaliar o desempenho da utilização de alguns modelos de piloto automático em cana-de-açúcar e citros. Na cultura da cana-de-açúcar o objetivo foi avaliar a acurácia de sistemas de piloto automático na operação de abertura de sulcos. Na cultura de citros o objetivo foi avaliar a acurácia do sistema de piloto automático na abertura de sulcos para transplantio e analisar o desempenho operacional e econômico do sistema de piloto automático confrontado como a prática usual, de alinhamento ótico e manual. No primeiro foram realizados ensaios combinando dois tipos de piloto automático (universal e integrado), na abertura de sulcos para plantio de cana, em diferentes tratores, com dois tipos de sinal de GPS (SF1 e RTK) na operação de abertura de sulcos em canade- açúcar para avaliar o erro de paralelismo dos equipamentos. Os ensaios foram realizados com três repetições em percursos retos e curvos. Para o cálculo dos erros de paralelismo utilisou-se um GPS com sinal RTK coletando os dados de cada percurso sendo possível determinar o posicionamento em relação à linha referencia A-B. A segunda parte do trabalho, com citros, foi dividida em duas etapas. A primeira consistiu em georreferenciar as plantas com sulcos feitos com e sem a utilização de piloto automático. Na segunda etapa do trabalho foi conduzida a avaliação da capacidade operacional da abertura de sulcos, com e sem a utilização de piloto automático coletando dados de tempos e de movimentos com um receptor de GPS. Para os ensaios em operação de abertura de sulcos no plantio de cana-de-açúcar com utilização do piloto automático o sistema integrado obteve melhor desempenho que o sistema universal tanto em percursos retos quanto em percursos curvos. Em percursos retos o sistema universal 200 obteve valores de erros médios menores que o sistema universal 100, o oposto ocorrendo em percursos curvos. O sinal RTK obteve melhor acurácia em relação ao sinal SF1. Na implantação de pomares de citros foi obtido um erro médio de desalinhamento de 0,08 m em sistema convencional de sulcagem contra um erro médio de 0,04 m do piloto automático. A operação de sulcagem utilizando o piloto automático apresentou uma eficiência de campo média menor. Porém, com piloto automático foi possível trabalhar com velocidades maiores, o que resultou numa maior capacidade de campo efetiva e consequentemente menor custo operacional. / For the sugarcane scenery one of the sustainability problems is the indiscriminate traffic of machinery wheels on the sugar cane, especially in the mechanical harvest, due to misalignment of the cane rows and difficulty of maintenance of the vehicles and compositions away of the crop rows. This is the reason the technologies of auto-guidance systems are succeeding in the sugar cane business. In the scenery of the citrus the implantation of an orchard is a stage of extreme economical importance due to the high cost, once several automated operations are involved. After the soil tillage, the manual alignment of the rows is accomplished for the transplanting, stage that demands the use of a team composed by a topographer and about 8 to 10 staffs. The use of auto-guidance systems provides the elimination of the manual alignment of the rows for transplanting and consequent reduction of the number of staffs. The technologies of autoguidance systems based on orientation through satellites intend to improve the alignment and the operational capacity of mechanized operations. The target of this work was to evaluate the performance of the use of some auto-guidance systems in sugarcane and citrus. In sugarcane the objective was to evaluate the accuracy of auto-guidance system in the furrows opening. In citrus the target was to evaluate the accuracy of auto-guidance systems in the opening furrows for transplanting and to analyze the operational and economical performance of an auto-guidance system compared to the usual practice, of optic and manual alignment. In the first test, on sugar cane, two types of guidance systems (universal and integrated) were involved, with two types of GPS signals (SF1 and RTK) and two types of tractors (Valtra BH 180 and John Deere 7815). Three replications were accomplished in the operation of opening furrows to evaluate parallelism errors of auto-guidance equipments in straight and curved tracks. The second part of the research was divided in two parts. The first stage consisted on georreferencing the plants in the field three months after the transplanting using both technologies for furrows opening, auto-pilot and manual alignment. In the second stage field capacities were evaluated by collecting data with a GPS receiver, with the tractor under the two conditions, with and without auto-guidance use. For the tests on opening furrows in sugarcane the integrated auto-guidance obtained better accuracy than the universal systems in straight tracks and in curved tracks, presenting lower aligning errors. In straight tracks the universal system 200 resulted in lower error values than the universal system 100. The universal system 100 resulted in lower errors in curved lines than the universal system 200. All the evaluated technologies obtained better performance in straight tracks. RTK signal had better accuracy when compared to SF1. In the implantation of citrus orchards the average aligning error on furrows opening was 0.08 m in the conventional system against 0.04 m for the auto-guidance systems. The opening of furrows operation using the auto-guidance presented lower field efficiency. However, with auto-guidance it was possible to work with higher speeds, what resulted in a higher field capacity and smaller operation cost.
9

Estudos sobre desempenho de sistemas de piloto automático em tratores / Studies of auto-guidance systems performance in tractors

Tiago Carletti Antunes de Oliveira 09 October 2009 (has links)
Para o cenário da sustentabilidade da cana um dos problemas é o tráfego indiscriminado de rodados sobre as soqueiras, especialmente na colheita mecanizada, devido a desalinhamentos das fileiras de cana e dificuldade de manutenção dos veículos e composições devidamente afastados destas. Assim, as tecnologias de direcionamento automático estão ganhando espaço no setor sucroalcooleiro. No cenário da citricultura a implantação de um pomar é uma etapa de extrema importância econômica, uma vez que estão envolvidas diversas operações mecanizadas. O alinhamento das fileiras é feito manualmente, etapa que demanda a utilização de uma equipe composta por um topógrafo e cerca de 8 a 10 funcionários. A utilização de sistema de direcionamento automático (piloto automático) elimina esta operação consequentemente reduzindo o número de funcionários. A partir disso o objetivo desse trabalho foi avaliar o desempenho da utilização de alguns modelos de piloto automático em cana-de-açúcar e citros. Na cultura da cana-de-açúcar o objetivo foi avaliar a acurácia de sistemas de piloto automático na operação de abertura de sulcos. Na cultura de citros o objetivo foi avaliar a acurácia do sistema de piloto automático na abertura de sulcos para transplantio e analisar o desempenho operacional e econômico do sistema de piloto automático confrontado como a prática usual, de alinhamento ótico e manual. No primeiro foram realizados ensaios combinando dois tipos de piloto automático (universal e integrado), na abertura de sulcos para plantio de cana, em diferentes tratores, com dois tipos de sinal de GPS (SF1 e RTK) na operação de abertura de sulcos em canade- açúcar para avaliar o erro de paralelismo dos equipamentos. Os ensaios foram realizados com três repetições em percursos retos e curvos. Para o cálculo dos erros de paralelismo utilisou-se um GPS com sinal RTK coletando os dados de cada percurso sendo possível determinar o posicionamento em relação à linha referencia A-B. A segunda parte do trabalho, com citros, foi dividida em duas etapas. A primeira consistiu em georreferenciar as plantas com sulcos feitos com e sem a utilização de piloto automático. Na segunda etapa do trabalho foi conduzida a avaliação da capacidade operacional da abertura de sulcos, com e sem a utilização de piloto automático coletando dados de tempos e de movimentos com um receptor de GPS. Para os ensaios em operação de abertura de sulcos no plantio de cana-de-açúcar com utilização do piloto automático o sistema integrado obteve melhor desempenho que o sistema universal tanto em percursos retos quanto em percursos curvos. Em percursos retos o sistema universal 200 obteve valores de erros médios menores que o sistema universal 100, o oposto ocorrendo em percursos curvos. O sinal RTK obteve melhor acurácia em relação ao sinal SF1. Na implantação de pomares de citros foi obtido um erro médio de desalinhamento de 0,08 m em sistema convencional de sulcagem contra um erro médio de 0,04 m do piloto automático. A operação de sulcagem utilizando o piloto automático apresentou uma eficiência de campo média menor. Porém, com piloto automático foi possível trabalhar com velocidades maiores, o que resultou numa maior capacidade de campo efetiva e consequentemente menor custo operacional. / For the sugarcane scenery one of the sustainability problems is the indiscriminate traffic of machinery wheels on the sugar cane, especially in the mechanical harvest, due to misalignment of the cane rows and difficulty of maintenance of the vehicles and compositions away of the crop rows. This is the reason the technologies of auto-guidance systems are succeeding in the sugar cane business. In the scenery of the citrus the implantation of an orchard is a stage of extreme economical importance due to the high cost, once several automated operations are involved. After the soil tillage, the manual alignment of the rows is accomplished for the transplanting, stage that demands the use of a team composed by a topographer and about 8 to 10 staffs. The use of auto-guidance systems provides the elimination of the manual alignment of the rows for transplanting and consequent reduction of the number of staffs. The technologies of autoguidance systems based on orientation through satellites intend to improve the alignment and the operational capacity of mechanized operations. The target of this work was to evaluate the performance of the use of some auto-guidance systems in sugarcane and citrus. In sugarcane the objective was to evaluate the accuracy of auto-guidance system in the furrows opening. In citrus the target was to evaluate the accuracy of auto-guidance systems in the opening furrows for transplanting and to analyze the operational and economical performance of an auto-guidance system compared to the usual practice, of optic and manual alignment. In the first test, on sugar cane, two types of guidance systems (universal and integrated) were involved, with two types of GPS signals (SF1 and RTK) and two types of tractors (Valtra BH 180 and John Deere 7815). Three replications were accomplished in the operation of opening furrows to evaluate parallelism errors of auto-guidance equipments in straight and curved tracks. The second part of the research was divided in two parts. The first stage consisted on georreferencing the plants in the field three months after the transplanting using both technologies for furrows opening, auto-pilot and manual alignment. In the second stage field capacities were evaluated by collecting data with a GPS receiver, with the tractor under the two conditions, with and without auto-guidance use. For the tests on opening furrows in sugarcane the integrated auto-guidance obtained better accuracy than the universal systems in straight tracks and in curved tracks, presenting lower aligning errors. In straight tracks the universal system 200 resulted in lower error values than the universal system 100. The universal system 100 resulted in lower errors in curved lines than the universal system 200. All the evaluated technologies obtained better performance in straight tracks. RTK signal had better accuracy when compared to SF1. In the implantation of citrus orchards the average aligning error on furrows opening was 0.08 m in the conventional system against 0.04 m for the auto-guidance systems. The opening of furrows operation using the auto-guidance presented lower field efficiency. However, with auto-guidance it was possible to work with higher speeds, what resulted in a higher field capacity and smaller operation cost.
10

Geodetické práce v investiční výstavbě. / Surveying measurement in the capital construction.

PÁLENÍKOVÁ, Lenka January 2009 (has links)
The accuracy appraisal and its evaluation with what the results of geodetic work are being achieved will be shown in this graduation thesis. As well as the related legislation and economic point of view of the price setting in comparison to other geodetic companies. One of the major surveyed area is testing of the used instruments - confrontation of achieved values with the values stated by manufacturer, accuracy analysis of the used methods and allignment of independent measurements of equal magnitude.

Page generated in 0.1229 seconds