ROAD SURFACE STRUCTURE MONITORING AND ANALYSIS USING HIGH PRECISION GPS MOBILE MEASUREMENT SYSTEMS (MMS)

摘要

Roads are the lifeline of a nation. This paper aims to introduce an effective road maintenance program using enhanced automated data capturing systems that simplifies evaluation of deteriorating pavement surface, resulting to an efficient management and maintenance of road infrastructure assets. PASCO Philippines had carried out numerous Road Pavement Surface Deterioration Survey using data captured from High Precision GPS Mobile Measurement System (MMS) vehicles. These MMS vehicles can capture point cloud data and high resolution images while the vehicle is in motion. The acquired high quality data can then be used for analysis and evaluation of road surface condition based on the International Roughness Index (IRI). MMS can calculate the position of the vehicle every 0.5 seconds using GPS and collects the 3 axis orientation using Inertial Measurement Unit (IMU) sensors to determine the vehicle's supplementary position. Several precision calibrated sensors such as; 3 GPS units in triangle position, IMU and odometer (distance and acceleration), and 6 high definition cameras working in tandem with 4 long range/high density laser scanner (within 10cm(rms)@ 7m precision), allows the vehicle to implement overlaying of colored 3D laser point cloud data and image data. The resulting data can be used to grasp precise road spatial information. A 3D Mapping system (PADMS), developed by PASCO Corp. Japan, can superimpose the acquired 3D laser point clouds onto the high resolution images taken by the cameras. Users can directly edit Geographic Information Systems (GIS) data, such as shape files and geographic database, generate cross sectional views of terrain and features at any position to obtain height data. Rutting (wheel track), longitudinal roughness or evenness can be automatically extracted, to some extent, through 3D point cloud data analysis. Since it is difficult to acquire road cracks in point cloud data, it can be extracted by highly qualified operators utilizing the captured high resolution images. Road flatness characteristics (σ) is corrected using supplementary values acquired from other information. IRI of each segment or section is calculated using the formula 「IRI=1.33σ+0.24」 .