The Design And Verification Of Track Database Based On XML

The track database based on XML stores and displays track data by data management and operational advantages of XML document. With the rapid development of High Speed Rail, large amounts of complex track data require a lot from the database. The self-descriptive and extensible features of XML have brought great convenience for the data exchange and sharing, and realize the tree-structure hierarchical management of data. This paper has explored a track database based on XML, which can meet the storage, management and application requirements of railway data. The GPS satellites still have defects like the limited range of visibility, which can be fixed by the stable navigation information—track database. Track database can be used to assist train positioning, correct the positioning drift and gross deviation in the process of train positioning by GPS alone. As the key technic for the future development of train positioning system, track database plays a major role in improving the positioning accuracy, reducing transportation cost and promoting operation efficiency.Based on a large amount of GPS track-measuring data, this thesis has accomplished the tree structure modeling of track database using DOM theory, and the track database design based on XML. It has also realized the hierarchical management of track-measuring data by XML data base, as well as the generation and display of track circuit diagram and diagrammatic sketch.Then this thesis has analyzed the realizability of train positioning assisted by track database from four parameters of train-control system navigation performance standard—accuracy, integrity, continuity and usability. It has explored a train positioning approach assisted by track database, through which the train positioning can be carried out by determining the last two continuous data points in the track database passed by train and using the model of linear mathematical dissemination.At last, this thesis has designed a simulated platform to verify track database. By comparing the results between using GPS alone and using GPS combined with track database, it has proved that track database can effectively improve the accuracy of GPS application in railways. Furthermore, as an additional measured value, the accuracy of this track database is going to influence the positioning accuracy of the train. In practice, track database not only has to meet the security requirements of train-control system, but also has to control the cost effectively. By comparing the accuracies of three accurately-different train-positioning track database, this thesis has also provided proposals for issues like how accurate the track database building should be.