Research On Vehicle Positioning System Of Urban Transport Based On DAB Signals

The best means to resolve traffic problems is developing intelligent traffic system (ITS), vehicle location technology is a crucial technology in ITS. Now it has developed a number of technologies to estimate the location of vehicle, such as signpost, dead reckoning, global positioning system (GPS) and so on. Because of the high density buildings and vehicles in the city, there is much disadvantage, for instance, long-term construction, high working cost, large investment of infrastructure and positioning equipment, fallibility of positioning accuracy and stability.DAB as a new information transfer technology began to enter people's lives along with the promulgation of digital audio broadcasting standard. It has the advantages of high frequency utilizing rate, robust anti-multipath interference, reliable delivery to portable and mobile receivers; the base stations do not need as frequent updates as satellite positioning. Therefore, the positioning of vehicles by using DAB signals is feasible.On the base of terrestrial digital broadcasting infrastructure, this thesis was constructed a new dynamic positioning system which bases on DAB in urban areas. The 3-dimensional spatial coordinate of vehicle can be determined by receiving a number of known terrestrial digital broadcasting transmitter signal. This paper analyzed the techniques concerning current vehicle location and the necessity and feasibility of the positioning system using DAB signals. The article derived Pseudo-range measurement mathematical model and location model, a vehicles positioning method based on epoch achieve asynchronous sequential location principle and DAB symbol timing synchronization technique was presented. According to the requirements of vehicle dynamic positioning technology, this article designed the DAB vehicle positioning system structure and functional module. The paper detailed the positioning module of software localization process, and extended Kalman filter algorithm is used to position resolution. On this basis, using Matlab software system to measure the pseudo-range is simulated, the authors construct that DAB positioning system and positioning scheme is feasible, Simulation error is about 3 meters, vehicle location and requirements can be achieved. This paper analyzed the system may produce error sources, and put forward some solutions. The new vehicle positioning system has a high probability in urban areas, low cost, easy to implement and so on, not only to add a vehicle positioning method of choice, but also can effectively compensate for the shortcomings of other location methods.