Research On Information Quality Of GPS For Advanced Public Transportation Systems

Advanced Public Transportation Systems (APTS) is an important part of Intelligent Transport System (ITS). The core method of improving the public service level is to use Global Position System to enhancing PT dispatch system and information service.Firstly, the article discussed the application of GPS location technique to public traffic system. Through analyzing the information need, the information attribute and the information quality requirement of public location system, a comprehensive analytical of GPS information error can result from the parts of collection, processing, transmission and application. In view of the kinds of error, the article brings up improvement method. The confidence of position state can be obtained by using the rank blur actuality assessment model. The scientical and rational evaluation of GPS information quality will provide scientific basis and data supporting to the data fusion and map-matching.In order to improve the quality of GPS information, the paper gives the data processing model—Kalman filtering model and the selection of parameters used in static situation or in dynamic situstion in the model. The noise data and the unreasonable data can be removed from the original data through Kalman filtering. Matlab simulation shows that after using data fusion algorithm, the GPS location accuracy is better than the initial GPS location accuracy.Finally, the article use the geographic data of the digital map to registrate the bus location data, that called map-matching, to coordinate the error that caused by the GPS location information and the road infoumation on the electronic map. The map-matching algorithm performance is verified through the experiment.