The Research Of Train Group GNSS-based Trajectory Simulation System

Train positioning technology can provide the position information of trains in service timely and accurately, making sure the trains working effectively and safely. Train positioning technology based on GNSS (Global Navigation Satellite System) can cut down the trackside equipment and has got big development because of its interoperability and security with low cost. Companies at home and abroad devote themselves to put the train positioning technology based on GNSS into the safety critical system such as train control system and train signal system. Before these systems being used in real life, lots of tests must be done. That’s why the reasonable tests are needed, including the single point test of fixed point, multi-point test without interruption and repeated line testing. However, these tests are restricted by some objective conditions on the railway. To simulate the real test environment, overcome the difficulty of designing the repeat test scenes and reduce the time and cost of designing, developing and testing the system, it is necessary to do some simulation work of train group satellite positioning trajectory. Multi-trains, multi-lines and multi-scenes data cannot be simulated by traditional methods. This paper provide a simulation system of train group satellite positioning trajectory to simulate this data mentioned and provide support for other similar systems.By simulating the train diagram, corresponding control strategies are got. And with the ephemeris data, station static data and digital track map data, train track and running state can be simulated, together with GNSS positioning data in corresponding format. Combine with station data and planning operation data, train diagram can be got. With the control strategies generated by train diagram, the train track module provide the train’s operating rules and show out the trace on GIS.The station occupied state identification can be got by station data, trace from train track module and the real train position. The number of visible satellites is one of the most important indexes for train positioning. This paper bases on ephemeris data, providing the number of visible satellites and visualizing them. The simulation of train speed including the ideal and the real speed curve and can be updated in real-time.The simulation system of train group satellite positioning trajectory is developed by C#under the environment of Microsoft Visual Studio2010. And the real data coming from the Shanxi coal railway transportation company, is putting into the system and the system is tested. In addition, this simulation system has a good performance in compatibility, scalability and functionality. The train group satellite positioning trajectory simulation system has been used in the projects of train warning system and GNSS speed ranging unit, working as the data source, providing various test data.