Study On Error Analysis And Correction Of Tunnel Space Detection Based On Mobile Laser Scanning

The tunnel geometry of the urban railway transportation is the basic security to the safety of the metro operation. Therefore, the development of high precision geometric deformation of the tunnel space detection technology has very important theoretical and realistic significance.This dissertation researches of the tunnel deformation of laser detection technology domestically and overseas, and discusses the typical mobile laser detection methods of track inspection car. Based on the analyses of the present situations of track inspection car measurement techniques, this dissertation proposes a road geometry deformation detection strategy by utilizing the mobile laser scanning,in which the design standards of the metro tunnel and the measurement principle of the laser scanner are considered adequately. Moreover, the corresponding error analysis and the correction of this scanning system are provided in this dissertation.The main research contents of this dissertation are as follows.(1) The mobile laser scanning system for the metro tunnel detection is designed and developed. This system adopts the positioning scheme based on the embedded ARM positioning synchronous technology, including the laser scanner, tilt meter,encoder, master control module, real-time data display module, the platform driver module, etc.(2) For the attitude measurable mobile laser scanning platform, the correction model of the spatial data in the situation of tilt is proposed in this dissertation. By utilizing the self-developed data processing software, the scanner data, the location data and the encoder data are combined, and the realistic tunnel space data could beobtained finally.(3) From the system structure of mobile laser scanning system, this dissertation analyzes the positioning principle of the system, the reference coordinate of each sensor and the coordinate transformation relations between each geometric model.Based on the principle of the scanner to get the point cloud data, the error sources of the scanning system are studied, and the scanning error estimation model of the point cloud data is proposed. Moreover, the error precision of the system is analyzed theoretically. Finally, the performance of the system is evaluated by simulations. The results prove the theoretical analyses.