Research On GPS Data Preprocessing Of Floating Car In Urban Traffic Guidance System

Along with the accelerated process of urbanization and duratived development of community economy in China, the number of private cars, taxis and other vehicles increased rapidly. On one hand, the huge increase in all kinds of traffic tools provide great convenience for residents in the city, on the other hand, these vehicles also bring traffic congestion, traffic accidents and other problems. The traffic problem has become an important problem in the development of economy and society.Urban Traffic Guidance System is an intelligent, safe, efficient, environmentally friendly and comfortable city comprehensive transportation system. The establishment of this system is based on the modern technology of electronic, computer, network and communication etc. In order to guide the distribution of traffic flow rational and change the city traffic congestion situation maximum, the essence of the system is making fu1 ll use of the intelligent management of traffic facilities and traffic guidance system with the current traffic information.As the important data basis of the real-time road traffic conditions identification and the urban traffic guidance realization, GPS road information collection technology, based on the floating car, plays an increasingly important role in improving traffic conditions and enhancing network capacity in Intelligent Traffic Guidance System with the rapid development of geographic information and satellite positioning technology. In order to solve the various possible problems of GPS floating car traffic information collected in the complex city environment, the main contents of this thesis are as follows:(1) To improved the traditional grey prediction model clock. Clock bias prediction model has a wide range of applications in decoding GPS position receiver in complex urban environment. Two order polynomial model, high-order polynomial model and linear model are the mainly used clock bias prediction models, but they all have their limitations. This thesis used GPS satellite clock bias data in different period of time, analyzed satellite clock bias prediction with different sample interval, the relationship of grey prediction model exponent and prediction precision. Experiment verificated that the improved grey prediction model proposed in this thesis can provide high accuracy satellite clock products for real-time dynamic GPS precise point positioning through the contrast with IGS ephemeris satellite clock bias data.(2) To put forward a new ambiguity definition method to solve the problem of carrier phase positioning in complex urban environment by using multi epoch data to construct equation. The simulation results show that the new ambiguity definition method can position fast and accurate when the floating car GPS data occurs cycle slips with three available satellites.(3) To analysised floating car GPS data, there are four main problems affecting the accuracy of intelligent traffic guidance system: the taxi driver drives a car in a place to hang around for a long time; the taxi waits for passengers; GPS receiver data occurs drift error; GPS receiver data occurs jump point error. Experiment results show that the precision of floating car GPS data has been improved after these pretreatments...