Underground 3D Topography Measured by Radar Sounding

Abstract

Underground three-dimensional topography measured by sounding of radio waves with the help of ground penetrating radar (GPR) has been studied. Our goal is to obtain and analyze a 3D representation of experimental data on the passage of plane polarized electromagnetic radiation through real underground objects and the intensity of its reflection received by the receiver antenna. We are developing an inductive method. The radio sounding using of the GPR SDI K-5 with frequency range of 1÷10 MHz at depths of 10, 20 and 40 m and surface area 50×20 m has been researched. Experimental data of radio sounding was written in the ASCII table by microcontroller. The use of computer processing by OriginLab program of experimental GPR data made it possible to obtain a three-dimensional image of the anomalous area, from which the reflected electromagnetic signal comes much weaker than from neighboring areas. Measuring the response of only the electrical component makes it possible to identify areas containing water, since water has a dielectric constant that is much higher than that of terrestrial rocks. Measuring the response of only the magnetic component makes it possible to detect anomalous regions containing materials with high magnetic permeability and significantly affecting the intensity of the reflected radio wave. The accuracy of determining the geometric dimensions is limited by our measurement step for surface (5 m) and sounding underground depths (10, 20 and 40 m). This is sufficient for large underground domain. The information content of 3D graphs and the accuracy of measurements of geometric parameters can be significantly increased.

Keywords

• 3d topography
• ground penetration radar
• radio wave sounding
• underground scattering
• geometric parameters measurement