Study On Buses Positioning Based On Mobile Phone Location & Map Matching

The development of intelligent public transportation system (IPTS) is one of efficient ways to solve the problems of urban traffic congestion. As one of the most important technologies, buses positioning can bring convenience to passengers, implement route guidance, carry on vehicles monitoring and dispatch vehicles. At present, there are several buses positioning methods, such as GPS, dead reckoning and inertial navigation, all of which the accuracy of GPS is the best except for the higher equipment investment, lost signals because of"the city canyon"and over dependence of overseas technology. Therefore a new location technology is still needed in future.Mobile phone location, which gets a rapid progress in positioning accuracy, is a new kind of location technologies with the development of mobile communication system. Due to many advantages such as the lower cost and investment, easy after-sale service, alterable operation of active and passive location, it has become a more and more popular topic. Accordingly, this paper applies mobile phone location, electronic map of high accuracy and reliable map matching algorithm. It matches the buses location points on the road aiming at improving the accuracy of buses positioning.Compared to many kinds of mobile phone location technologies, the proposed algorithm chooses reliable TDOA location method to implement the buses'location. Due to the analysis of the TDOA error model, TDOA location points and TDOA error ellipses are obtained by the repeated location simulation and statistical analysis. In the process, the error ellipse parameters of characteristic points in location region are gained in advance in order to enhance the system'operation efficiency and precision. According to the analysis of the characteristic of error ellipse in location region, a characteristic table is established and then the TDOA location points and error ellipse parameter can be got sequentially by the fuzzy pattern recognition map matching algorithm, which adopts extrapolation position and the distance between the location point and the road to obtain the matching road section and matching points. In the experiment, this described algorithm is compared with the typical point-line algorithm. The results demonstrate that it is superior in the aspects of reliability, location efficiency, matching rate and position error.Finally, upon the request of the buses location in IPTS, a new architecture of buses positioning system based on TDOA location technology & map matching is designed and the real-time demo is implemented by VB & MapX platform. The experiment shows that it can meet the needs of timeliness and reliability.