نتایج جستجو برای: gpr wave
تعداد نتایج: 220482 فیلتر نتایج به سال:
inverse problem is one of the most important problems in geophysics as model parameters can be estimated from the measured data directly using inverse techniques. in this paper, applying different inverse methods on integration of s-wave and gpr velocities are investigated for estimation of porosity and water saturation. a combination of linear and nonlinear inverse problems are solved. linear ...
Directional decomposition of GPR data is possible when multi-component multi-offset GPR data is available on a surface. The decomposed wave fields are propagating in the two opposite directions perpendicular to the recording surface. These two decomposed wave fields are related to each other through a reflection operator. This operator represents the reflection response of the medium on the sid...
Acoustic wave transducers act as cooperative targets for passive, wireless sensing by converting an incoming electromagnetic pulse to an acoustic wave whose velocity is dependent, by design, with a given quantity under investigation. The acoustic wave is delayed and emitted back to the measurement electronics as an electromagnetic pulse by direct piezoelectric effect. In the context of sub-surf...
We tested an off-ground ground-penetrating radar (GPR) system at a fixed location over a bare agricultural field to monitor the soil freeze-thaw cycles over a snow-covered surface. The GPR system consisted of a monostatic horn antenna combined with a vector network analyzer, providing an ultra-wideband stepped-frequency continuous-wave radar. An antenna calibration experiment was performed to f...
The selection of a near-field or far-field ground-penetrating radar (GPR) model is an important question for an accurate but computationally effective characterization of medium electrical properties using full-wave inverse modeling. In this study, we determined an antenna height threshold for the near-field and farfield full-wave GPR models by analyzing the variation of the spatial derivatives...
determination of the thickness of a mountains glacier like alamkooh is very difficult due to its extremely cold climate conditions and high elevation, risk of falling large snow segments or balls and coarse topography of the glacier. in this research, due to the transparency of ice for electromagnetic (em) waves, and also, that ground penetrating radar (gpr) method is non-destructive, fast and ...
Traditional finite difference time domain (FDTD) is classic numerical method for solving wave propagation problems such as electromagnetic wave, seismic wave and acoustic wave. As for airborne GPR simulation, modeling space is so large that memory consuming is pretty huge; on the other hand, the area between source antenna and ground surface is homogenous medium – air, where analytic solution c...
A linear inversion scheme for microwave imaging of buried objects is presented in which arbitrary antennas are accounted for through their plane-wave transmitting and receiving spectra. INTRODUCTION Ground penetrating radar (GPR) is an efficient tool for microwave imaging of buried objects. Within the concept of diffraction tomography, as proposed by Devaney [1], several linear inversion scheme...
A 30 m by 30 m two-dimensional grid was designed on a flat bench behind a quarry face of predominantly limestone with thin shale layers located at a Bonner Springs, Kansas site to test the utility of ground-penetrating radar (GPR) for stratigraphic studies. GPR data were collected along seven lines parallel to the quarry face and seven lines perpendicular to the quarry face, each separated by 5...
This paper studies the dispersion of GPR wave’s phase velocity at different wideband frequencies in plywood and concrete with varying moisture content. study makes use two antennas 2 GHz centre frequency operating wide angle reflection refraction (WARR) mode computation spectral analysis surface wave (SASW). Computation velocities is based on acquisition cross-power spectrum unwrap distorted gr...
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