Research On Vehicle Positioning Simulation Technology Based On GPS

In recent years, with rapid economic development and transport demand growth, construction of urban transport system has to become a top priority. Intelligent Transportation Systems (ITS) as a solution to the problem of transport has been the top technical of people's attention. The most basic information parameter in traffic system is the location information of moving vehicle, so obtaining high-precision location information are essential for intelligent transportation systems research.According to the features of vehicle positioning, GPS is researched deeply. And then the vehicle positioning simulation system based on GPS is designed and developed. The movement information of vehicle is obtained by the data processing, then, according to the simulated positioning information. The basis is provided for traffic management, traffic plans and the simulation of traffic system.The system composition of GPS, positioning principle and the factors of influence precision are described in this paper. The position data of GPS satellites and the picture of three-dimensional trajectory are obtained by means of programming on the basic of history data.An improved constellation-selecting algorithm is proposed, and it has been tested and verified. Through the simulation of satellite movement, the choice of best positioning satellite and the design of GPS receiver, the locations information of vehicle can be converted into the GPS signal to input to the module of virtual driving so as to realize the experiments of the GPS vehicle positioning simulation. The obtained virtual positioning data can meet the demand of off-line study.The positioning accuracy is improved because of the combined positioning technique in the complex environment. A combined positioning and tracking system based on GPS and CDMA is proposed. GPS positioning technique is chosen firstly, and the triangle location of CDMA is chosen when the GPS signal is occluded in the technique. The bidirectional alternation of navigation and positioning information is realized rely on the CDMA. The proposed system can offer the best geographic navigation information for user, and the location information of other members is obtained.In the virtual environment, collision detection is the important technique in system simulation. It is the main influence factor for fidelity and feeling of reality. Some collision problems are deeply analyzed, especially the collision detection and collision response are discussed between vehicle and object, vehicle and terrain, and about the line of sight. Finally, simplified bounding boxes and terrain matching algorithm are proposed, in which a set of practicable simulation models are established.