Research And Design Of Railway Locomotive Positioning Technology Based On Real-time PPP

Since twenty-first Century,the development of railway transportation has a great change.At the end of 2015,the national railway mileage has reached 121,000 kilometers,of which the high-speed railway is reached 19,000 kilometers.While in 13th Five-Year to 2020,the railway network is planning to reache 150,000 kilometers,including 30,000 kilometers of high-speed railway.With the rapid development of high-speed railway,it is more and more important for the safe operation,maintenance work.For the realization of China's railway system control center for maintenance of locomotive real-time and intelligent scheduling,utilizing mobile network as the transmission carrier,real-time information acquisition,remote monitoring and maintenance of GYK equipment has become direction of railway monitoring system.This paper use the totally coverage of 3G network along the railway,combination of real-time precise positioning and odometer positioning method,thus can complete the functions of railway vehicle real-time location monitoring and scheduling,and established the railway locomotive monitoring system.Based on those,the main works are as following,In this paper,the PPP theory and the classification of errors are introduced in detail,and the recovery methods of precise orbit and clock error are studied.At the same time,the odometer(ODO)positioning principle and error sources are introduced.This paper puts forward the method of using the railway track data to establish the linear constraint model,combined with the PPP observation equation to reform a new observation equation,to enhance the PPP positioning with additional constraint.This method is used to improve the convergence time of precise positioning,and also to provide constraints for the real-time positioning and improve the positioning accuracy.The results of the convergence time of 3 days is increased by 49.1%,53.8%and 10.4%,respectively.The positioning accuracy of the horizontal is increased by 29%,43.8%and 69.5%,respectively.The elevation accuracy is increased by 43.3%,50%,and 65.6%,respectively.Proposed and implemented the railway locomotive positioning under the condition of satellite signal lost track.Obtaining the real-time odometer data and it will be obtained as integral observations,then calculate occlusion area position with maching the database.The residuals of the curve segment is 0.6m,and line segment is 0.5m in a short period.The results show that this method has a good auxiliary effect on the railway lovomotive positioning,and can effectively complete the location of the train.With the additional constraint model and the positioning algorithm of odometer information,it is applied in the railway monitoring system in Hefei city.In this system,we mainly completed the data collection and sorting,including signal location,kilometer node location and station location,fork and railway section location.The railway map solution of the track map data,including the use of PPP-RTK post-processing model for calculation and node segmentation,data resampling.The performance of the wide area real-time positioning products is evaluated,including the precision of orbit and clock error,and the precision of real-time positioning precision in different experimental environments.Static simulation of dynamic,horizontal accuracy is better than 5cm,elevation accuracy is better than 1 Ocm.Under the condition of vehicle positioning,the horizontal precision is better than 0.3 m,the elevation is better than 0.5 m.The experimental results show that the positioning results can meet the demand of railway location.