A Dynamic Detection Method for Railway Track Irregularities Combining Line-Structured Lasers and GNSS/IMU

A method combining line-structured lasers and GNSS/IMU sensor groups was proposed for dynamic detection of geometric irregularity parameters of railway tracks. 4 sets of line-structured lasers and a set of GNSS/IMU modules are mounted on a small track inspection vehicle and used to collect 3D point clouds of the track area, then through hard synchronization, the point cloud of the left and right track areas was fused with the sensor space pose parameters to obtain the point cloud model of the track area in absolute coordinates system. Use the combination of straight-through filter and cloth filter to extract the center line of the top surface of the rail and the gauge measurement reference line, then calculated the track irregularity parameters based on the filtering results. The method in our paper was verified on a test railway section. The results show that the proposed method can accurately obtain the center line of the rail top and the reference line of the gauge measurement, and can quickly and dynamically implement the five irregular geometric parameters of height, level, twist, rail direction, and gauge, and the accuracy can reach mm level measurement.