Research On Data Quality Evaluation Of The Digital Track Map For Train Control Applications

GNSS-based train control system uses satellite positioning data for train localization and control, in which digital track map is the key basis. During the generating process of digital track map, including data collection, data archiving, data processing and so on, there are some data errors in a certain degree, which will seriously threaten the safety of train control system.The current quality control method of digital track map mainly focuses on the field verification, but this method can only extract key point data from digital track map to re-mapping and give summary analysis of digital track map accuracy. This method cannot validate the entire map or detect the artificial operation error in the production process of digital track map. The current digital track map verification work is lack of a complete evaluation system and the verification index is not clear. Besides, the verification work is lack of professional evaluation software, the efficiency of verification is low, and the detection is not comprehensive. The purpose of this thesis is to solve these problems in the evaluation of digital track map.The main contents of this thesis include:The thesis constructs a comprehensive digital track map evaluation system. Several quality elements such as precision, integrity, availability, consistency, safety and so on are selected to make the evaluation work rule-based. The thesis builds a rule database of digital track map, and all kinds of the data of the digital track map are cross validated to ensure the consistency.The thesis proposes a track evaluation method based on route classification. It uses the line segmentation algorithm to accurately separate the track into segments, and then evaluates them based on different linetypes. Also the smoothness monitoring algorithm of track map data based on wavelet transform is put forward to locate the singular points and to carry on the multi-scale analysis on the map smoothness. The cloud model is introduced into the evaluation of digital track map, which ensures the accurate conversion between the quantitative and the qualitative evaluation results.A digital track map quality evaluation software is designed in this thesis, which improves the efficiency of map evaluation greatly. The software realizes the functions of the field verification and automatic detection, including accuracy, topology consistency and line smoothness of the map. It outputs the error information of the digital track map, generates evaluation report, and gives a scientific and comprehensive evaluation results.This thesis utilizes the data of Geermu Station, Nanshankou Station, Ganlong Station of Qinghai-Tibet Railway Line and Jinmei Station to conduct several tests on evaluation algorithm and software. The results prove the efficiency of the algorithm and the practicability of the software.