The Study Of Accurate Path Identification In Expressway Toll Collection System Based On GPS

With the rapid development of the highway in China, it has formed the complex network structure in most of the provinces or municipalities. Though in the same OD, the phenomenon may occur that the path is not unique. It causes great challenge to networked toll-collection in highway. On the one hand, in case of ambiguous path, how to collect the tolls is considered reasonable at the exit of highway. On the other hand, how to spilt tolls which have been collected is fair. Obviously, these problems can be solved easily if the route vehicles travelled can be made sure in the case of ambiguous path. So path identification is the key to solving these problems.There are several methods to recognize the path. Some of them are mature and even have already been applied in toll-collection. This paper uses GPS technology to achieve path identification and two schemes of getting path information are given. One of them is a composite passing card program and the other is the program of OBU couples with passing card. Both of the two options are accomplished by recording the data GPS offers in the passing card. Using the method of path identification may maintain the current charging operation platform constant, only upgrading or reforming some hardware and software of the system. And it is also compatible with the existing charging method.The program of OBU couples with Mifare card has been designed and implemented in this paper. It is demonstrated the feasibility of a passing card as a medium of recording path identification information. The computer test software is designed to simulate the lane toll system. Finally, three steps are made to finish the test: giving out the passing card and writing the starting point information into it, recording path information on driving and displaying the path information on the electronic map by reading the card. The test tells that the results coincide with the actual path.The volume of the circuit units of GPS chip, processor and so on, which are used in test is large. If they can be ultra-thin, the volume of the GPS antenna can be smaller and its sensitivity will be improved, the scheme of composite passing card is feasible. The program of OBU couples with passing card can be extended with ETC equipment.