Multi-Component Ground Penetrating Radar for Improved Imaging and Target Discrimination

Ground penetrating radar (GPR) is routinely used to image subsurface targets that have high degrees of directionality including faults, pipes, rebar, and unexploded ordnance. The ability to image and discriminate these subsurface targets depends strongly on the antenna configuration used and the orientation of the radar antennas with respect to the orientation of targets. However, designing optimal surveys is complicated by the fact that the dimensions and orientation of targets are often unknown. This dilemma is addressed by using a multi-component GPR survey technique that is sensitive to the vector nature of the received signal. The received instantaneous amplitude signals from this survey technique are represented by a second-rank tensor. Using tensor manipulations it is possible to determine the amplitude signal for any antenna orientation from two co-polar and one cross-polar antenna configuration. This is used to produce images of the subsurface for any antenna orientation, eliminating the need for prior knowledge of subsurface targets to design surveys. Also, the eigenvalues and eigenvectors of the amplitude tensor could be used to discriminate targets on the basis of polarization, and to determine their orientation. Field studies using buried pipes provide experimental support for this technique.