Imaging of buried structures by a GPR combined with a self-tracking total station

Abstract

One of the important features of ground-penetrating radar (GPR) is the visualization of subsurface structures with a higher resolution compared with other geophysical methods. In order to take full advantage of the imaging capability, the three-dimensional position of antennas needs to be tracked, which is required by imaging algorithms. We developed a GPR system that combines a position tracking system, which is a selftracking total station. The total station automatically tracks a prism attached on the GPR antennas while scanning and measures its position in threedimensional space. By scanning GPR antennas twodimensionally on the ground surface, a full threedimensional data set can be obtained. Using the position information synchronized with the GPR data acquisition, GPR traces can accurately be assigned to the locations that the data were actually collected, and thus, a more precise subsurface image can be reconstructed, compared with the conventional way of two-dimensional GPR scanning – setting a number of survey lines with tapes and positioning based only on distance measured by an odometer wheel. The system was tested in a place where a numbers of pipes were buried. The system successfully imaged these pipes. In this paper, the system configuration is illustrated and the imaging capability is discussed based on a measurement of buried pipes with the system.