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Many of localization techniques are available now a day’s such as Global Positioning System (GPS), Infrared, Ultrasound, and Bluetooth localization systems, Wi-Fi enabled devices and cellular mobile phones. Each of these techniques has its own advantages and disadvantages, but for their continuous network connectivity, low power consumption, wide adoption and their ability to offer indoor outdoor place detection capabilities cellular mobile phones are the best choice for location enhanced applications. There are five basic cellular positioning methods- proximity sensing, lateration, angulation, dead rocking, pattern matching- that measure many observables by different techniques. These cellular positioning methods varies a little bit according to the network they had been implemented on; as in GSM they turned up to (Cell ID + Timing advance, E-OTD, U-TDoA, and A-GPS) or in UMTS the turned up to (cell based methods, OTDoA-IPDL, and A-GPS). Those positioning techniques give a clue about two to four unknowns of the position (latitude, magnitude, altitude, and time). The more positioning techniques are combined, the more accurate positions are obtained.
The need of locating people has increased apparently than ever before because of many reasons; such as security purposes of emergency situations, terrorism and crime prevention. Not forgetting the effect of such service in increasing the revenues per user for Cellular Communication Service Providers by launching many of attractive feasible services; such as enquiry information services, community services, traffic telematic, fleet management and logistics, marketing and value added technologies.
A program by Turbo C++ has been prepared to simulate the process of mobile location determination using tri-angulations technique. The limits of time dedicated for the thesis forbids the availability of making a simulation for all other positioning techniques, so they had been left for further scopes.
In all operating mobile localization technologies there are always errors that affect the accuracy of location determination process in cellular networks, and add +(10m ~ 10km) according to the positioning technology used, reducing these errors margins is always an interesting subject for further researches. |
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