| Since the 20th century, the rapid development of wireless communication technology has profoundly changed the development direction of the world economy and people’s thinking and lifestyle.With the rapid popularization of intelligent terminals, Location Based Service is more and more applied to people’s life and work,and the positioning techniques is one of the core elements of Location-Based Services.Nowadays, due to people’s increasing demand for Location Based Service,indoor/outdoor seamless positionning techniques have became a hot spot for localization research.GPS is widely used in outdoor open area because of its wide coverage, high precision and high real-time performance. However, due to the buildings that will interrupt the satellite signal, the GPS will fail in the downtown and indoor areas. WiFi network with the characteristics of low cost, convenient deployment, widely distributed in indoor places (airport, campus, hospitals, commercial areas and residential buildings), which has became a hot spot for indoor localization research. But to achieve the effect of localization signals full coverage through GPS and WiFi is not enough, so the cellular network is introduced, which signal can cover the downtown area, also can cover almost all indoor areas. In summary, this thesis research on the switch among GPS/WiFi/Cellular localization, and uses the Android platform to realize it.Firstly, by reading a large number of literature about outdoor and indoor localization technology, then compared and analyzed of various localization technology to determine the feasibility and advantage of the scheme. Also introduced the related technology principles and characteristics, including the basic principle of GPS,the position fingerprinting localization algorithm, typical of the DCM algorithm, typical wireless signal propagation model and the Kalman filter, which makes preparation for the following work.Secondly, used MATLAB software to establish the simulation environment, then simulated and analyzed of the key factors influencing the location fingerprint localization algorithm performance:the basic DCM algorithm, K value, dimensions of fingerprint. Use fingerprint Kalman filter pretreat RSS raw data.By analyzing the Alpha-count mechanism, applied it to combine WiFi fingerprint localization and cellular fingerprint localization,then simulated and analyzed localization performance.Then, through analyzing the demand of the seamless positionning system, designed the general framework and implementation scheme of the indoor/outdoor seamless positionning system. At the same time, the key technique of each function module in positioning system is introduced in detail, and achieve it by eclipse sofrware.Finally, built a experimental environment of indoor and outdoor seamless positionning,and use the dsigned application to test and verify the function of position fingerprint data collection in Offline training phase,data storage and localization.At last,testing and analyzing the performance of the seamless positioning system. |
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