Design And Development Of An Indoor Real-Time Locating System

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Date
2010-01
Authors
Mohamed Elhefnawy, Mohamed Mohamed
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Publisher
Universiti Sains Malaysia
Abstract
Several locating technologies have been developed and commercially deployed including the Global Positioning System (GPS) and the wireless enhanced 911 service system (E-911), but these locating technologies are used mainly for outdoor locationbased applications and can not be used effectively inside buildings and in dense urban areas. Most of the commercial indoor localization systems provide a poor performance due to the presence of noise, interference, path loss, polarization mismatch, polarization reflection and the effect of the multi-path phenomenon in the wireless channel. Therefore, there is a need for a locating system which has a good performance in indoor environments . In this thesis, a wide variety of technical aspects and challenging issues involved in the development of indoor locating systems are discussed. The design and implementation of Real Time Locating Systems (RTLS) antenna system are presented first, then a new technique to estimate the Angle-Of-Arrival (AOA) is introduced, finally model development and implementation for the Time-Of-Arrival (TOA) estimator are discussed. It is shown that, the use of a quadrature hybrid as a feeder to the square patch microstrip antenna through two apertures produces circular polarization diversity, wide bandwidth and good axial ratio, besides minimizing the antenna size. Also the implementation of the 4×4 Butler matrix as a feeding network to the 2×2 microstrip antenna array generates four beams that have circular polarization diversity, high gain, good axial ratio and wide v bandwidth. In this thesis, the proposed technique to estimate the AOA improves the accuracy significantly without requiring high Signal to Noise Ratio (SNR). Moreover, as the AOA can be estimated without spatial sampling, the hardware requirements are less compared to the other methods.
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Keywords
Design And Development , Indoor Real-Time Locating System
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