Incorporation of Variable Background Velocity In Subsurface Imaging With GPR

For fast imaging subsurface targets with ground penetrating radar (GPR) it is common to assume<br>a homogeneous background of electromagnetic (EM) wave velocity. Nevertheless, if some information<br>about EM velocity is available, it is desirable to use more realistic velocity distribution in subsurface<br>target imaging. This paper introduces a ray tracing function into GPR imaging process with using<br>reflection energy stacking. We demonstrate the effectiveness of this approach by comparing the imaging<br>results with different velocity layers for a typical subsurface imaging example. Use of the ray tracing<br>technique in the imaging process built in GPR software, GIT-Radar, is better to image and determine the<br>depths and shapes of the targets. Also, the application of the ray tracing in a 3D imaging process does<br>not substantially retard the speed of calculation if a layered velocity model is used.