Buses Positioning Based On Multi Mobile Phone Location Estimation

The development of intelligent public transportation system (IPTS) is the most efficient approach to resolve the traffic problems in a metropolis, and automatic bus location system is the foundation of IPTS, it can collect the real-time locations of moving bus on the road, so to develop the technology of bus location plays an important role on constructing IPTS.Mobile positioning by cellular phone is a new location estimation technology with the development of mobile communication. Because of mobile phone used widely and mobile communication network covering broadly, the location by cellular phone can't blind spots even due to underpasses and bridges and it can be used to locate the bus in dense buildings. The location estimation by cellular phone can be additional approach to bus locationing when GPS is used. Because of low accurate location reports with single mobile phone, this paper advises firstly that multi-mobile phone is utilized to locating the bus, which they stay on for improving the location precision of the bus. The recommended method is a partnership of three kinds of technology. They are positioning by mobile phone, data-fusion and map matching. Data-fusion algorithm and map-matching algorithm are cores of proposed method.This paper compare firstly the location estimation by differences in the times-of-arrival (TDOA) with other mobile location methods, and decided to use TDOA to locate phones for tracking bus which phones stay on, design the whole sketch of bus location system based multi-phones. Then, we analyze the error statistic model when using TDOA to locate, discuss the statistic character of error distribution when using multi-phones location. According to the principle of data-fusion, we propose to use adaptive weighted average data-fusion algorithm to get the bus location by fusing the location of multi-mobile phone after discussing current main data-fusion algorithms. The simulation result shows this algorithm more efficient and accurate when comparing bus location based multi-mobile phone with based single mobile phone. On the foundation of data-fusion, the relationship of geometry error and the bus real location is analyzed, and the appropriate algorithm to filtering geometry error is proposed, its reliability is proved with simulation test records. Moreover, the relationship of bus estimation precision and the number of mobile phones tested is discussed.Finally, we designed the architecture and functional module of the buses positioning system based on multi-mobile phones location estimation by data-fusion. According to bus driving characters, the algorithm of bus map matching based on projection method is accounted. Simulation result proved it is available and advantageous in minimizing location error of buses.Simulation result shows that the bus location precision can be improved greatly by the method of bus location based on multi-mobile phone from low estimation precision based on single mobile phone, for example, when 3 mobile phones are located, bus location estimation precision is 46% of one based on single mobile phone, it can meet the need of bus location.