Design And Development Of An Indoor Real-Time Locating System
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Date
2010-01
Authors
Mohamed Elhefnawy, Mohamed Mohamed
Journal Title
Journal ISSN
Volume Title
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
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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.
Description
Keywords
Design And Development , Indoor Real-Time Locating System