High resolution ground penetrating radar imaging and characterization
Ground penetrating radar (GPR) is an important tool for a wide range of geological, hydrogeological and engineering investigations. Conventional processing techniques mainly use standard ray-based methods, which are often based on seismic processing techniques, and have limited resolution. Higher resolution images can be derived by using more sophisticated processing techniques that explicitly take into account the electromagnetic wave propagation. Here, two relatively new developments to obtain sub-wavelength resolution images are discussed, which return significantly higher resolution images in comparison with traditional ray-based methods.1) Dispersion inversion of dispersive GPR data measured over low-velocity or leaky waveguides cannot be analyzed using standard ray-based techniques due to the interference of the multiple reflections within the waveguide. An inversion scheme similar to seismic Rayleigh and Love wave inversion was recently introduced that consists of calculating phase-velocity spectra, picking dispersion curves and then inverting for the subsurface material properties by explicitly taking into account of the electromagnetic reflection and propagation characteristics. GPR data measured over a precipitation induced waveguide shows clear dispersion and is inverted for the medium properties. The obtained results correspond well with soil core analysis.2) Conventional crosshole tomograms provided by standard ray-based techniques have limited resolution, primarily because only a fraction of the information contained in the radar data is included in the inversion. Higher resolution radar tomograms can be derived by using full-waveform inversion schemes that take into account the entire recorded trace. Recently, a new full-waveform inversion scheme was developed that simultaneously updates the permittivity and conductivity distributions, exploits the full vector wavefield and is able to jointly invert crosshole and borehole-to-surface data sets. Here, we show that full-waveform inversion of synthetic and field data acquired within a gravel deposit returns significantly higher resolution images than standard ray-based inversion.
GPR inversion full-waveform dispersion waveguide
Jan van der Kruk Giovanni A. Meles Anja Klotzsche Rob W.Jacob Joseph A. Doetsch Niklas Linde Hansruedi Maurer Harry Vereecken Alan G. Green
Research Center Juelich, Juelich, Germany ETH Zurich,Zurich,Switzerland Bucknell University, Lewisburg, U.S.A University Lausanne, Lausanne, Switzerland ETH Zurich, Zurich, Switzerland Research Center Juelich,Juelich,Germany
国际会议
成都
英文
574-582
2010-06-14（万方平台首次上网日期，不代表论文的发表时间）