Research On GPS Data Simulation System Of Train Movement Trajectory

Nowadays train positioning technology has been paid great attentions because of its various advantages, such as lower cost, less trackside device, high positioning accuracy, easier installation and maintenance and so on. Due to the complexity of railway field environment, most new GPS technology must be tested at laboratory before applying to practical application, while at lab, the source of GPS receiver could not meet the requirement of test, traditionally,people may use GPS data emulator to do this kinds of tests, but there are some shortcomings of GPS data emulator that it can’t simulate multi-line GPS data at the same time, so it can’t meet the requirements of multi-train simulation test. On this basis, this paper has developed a GPS data simulation system, it can provide simulation GPS data of multi-train trajectory in the laboratory environment and provide basic data support for test and research of train positioning system based on GPS.Firstly, this paper has designed system architecture in the thought of high-level software architecture, the system is divided into presentation layer, logic layer and data layer. On the basis of hierarchical division, this paper has been divided and designed the functional module on all levels according to the functional requirements of the system. In the design, this paper has realized independent encapsulation of each functional module, so it can guarantee that the degree of coupling between various modules is low. At the same time, each module has also set aside corresponding interface which can provide support for the expansion of the system.This paper did research on train diagram simulation, satellite visibility simulation and train trajectory data simulation. Train diagram simulation was mainly simulating the train diagram based on railway station data and train operation timetable. Because the number of visible satellites is an important indicator to evaluate the accuracy of positioning, we has utilized satellite visibility prediction algorithm based on GPS satellite ephemeris to simulate the number of visible satellites which was changing with time and space, this paper has also realized the visualization of visible satellites. We need to specify path for the train in the data simulation process of train trajectory, in this paper, A*algorithm has been utilized as the train path’s searching algorithms, it can select the path for the train automatically, by using it the simulation efficiency has been improved. The simulation data produced by the system designed in this paper is in line with the standards of NMEA-0813, it can provide support for the interconnection test between various systems.Finally, this paper has established a GPS data simulation system of train movement trajectory using the C#language in Microsoft Visual Studio2010development environment, and has tested and validated the simulation system’s performance using Shanxi Coal Transportation Company railroad field data, and experimental results show that the system in terms of functionality, versatility and scalability are designed to achieve the desired goal. In addition, this paper has also done the research which is to provide data source for High Speed Railway Train Collision Early Warning System, and has achieved good results.