Research On The Positioning Algorithm And Data Transmission System Of The Rail Flaw Detection Trolley

Dual rail inspection vehicle is a new generation of railway inspection equipment which has the function of automatic inspection of rail defect points along the line.Conventionally,an odometer is required for the localization of the inspection vehicle.This localization mode will introduce accumulated error which cannot be automatically eliminated and needs to be manually corrected.The rail inspection data also needs to be manually transferred and stored.In order to solve the above problems,this paper proposes a data fusion algorithm combining satellite positioning and dead reckoning to realize automatic positioning of the vehicle.Moreover,a set of localization and data transmission system with 4G wireless transmission technology has been developed.The research contents of this paper are as follows:(1)The basic principle and error source analysis of satellite positioning and odometer dead reckoning has been studied.Based on the output demand of longitude and latitude,the earth coordinate system is selected and the coordinate conversion is carried out in the process of dead reckoning.The odometer positioning model is established.(2)Based on the extended Kalman filter(EKF),the combined localization method is designed.The GNSS/odometer combined localization model has been built to improve the accuracy and reliability of the inspection vehicle localization.(3)Based on the Raspberry,the vehicle terminal has been designed.ARM+GPRS+BDS architecture is adopted with the vehicle control integrated machine and internal program design to realize the functions of rail inspection data receiving,BDS data acquisition,combined data caching and forwarding and self inspection,etc.(4)Based on C#the remote data management platform has been developed.It realizes the functions of receiving and storing the data sent by the terminal,displaying the real-time flaw detection data as well as the moving track of the vehicle,and playing back the historical track,etc.That is convenient for the operators to monitor and manage the rail inspection process in real time.Finally,the modular function test of the hardware part in this system has been carried out,and the proposed combined positioning algorithm has been verified by the real vehicle test on Shanghai Hangzhou line.The experimental results show that our combined localization method can significantly improve the accuracy and robustness of the system compared with that of the single satellite method.