Research on Elevation Accuracy Improvement of Railway Track Alignment Measurement Based on Vehicle-borne LiDAR
In order to improve the efficiency of railway track profile measurement and reduce the safety risk,combined with the speed-up renovation project of an existing conventional railway in western China,this study adopted vehicle-borne lidar technology to improve the accuracy of vehicle-borne lidar elevation measurement from the aspects of system equipment selection,vehicle-borne lidar configuration,encryption of leveling control points and optimization of GNSS measurement scheme.The measurement scheme was constructed and the scanning of track and railway structures was carried out.Then,through point cloud matching,the corresponding relationship between the WGS84 linear coordinates collected by the feature point radar and the construction coordinates of the feature points collected by RTK was established,and the mathematical model of coordinate transformation was constructed.The model was used to map the coordinate space of the point cloud to the independent space coordinates of the designed railway construction project.Then,the track coordinates and elevation information were extracted by software,and the linear measurement of the railway track by the vehicle-borne lidar technology was realized.The results show that based on the vehicle-borne lidar scanning,the railway track profile measurement of the capacity expansion railway is encrypted to about 500 m according to the fourth-order leveling accuracy spacing along the leveling point.The elevation accuracy is conditionally controlled within 2 cm,and the elevation,100-meter standard measurement and dialing distance acquisition quality can meet the accuracy requirements of the railway track profile measurement of the capacity expansion railway.
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