Distributed/embedded sub-surface sensors for imaging buried objects with reduced mutual coupling and suppressed electromagnetic emissions

The proliferation of strategic subsurface targets has increased the need for remote sensing techniques providing for the accurate detection and identification of deeply buried objects. A new RF tomographic technique is proposed in this concept paper for developing RF CAT Scans of buried objects using spectral, spatial/angular, and polarization diversity. This tomographic imaging technique, developed by Wicks and presented in GPR 2004 [1], uses embedded subsurface radiators, delivered by earth-penetrating non-explosive, electronic "e-bombs", as the source of strong underground radiated transmissions. Distributed surface-contact sensors are used to collect the tomographic data for relay to a UAV and transmission to a remote site. Three-dimensional imaging algorithms have been developed to detect, image, and characterize deeply buried targets. By embedding the transmitters underground, reduced mutual coupling and EM emissions, and improved signal-to-noise ratios can be achieved. Simple surface SAR experiments over deep mine shafts have been performed to validate the 3D processing algorithms using 2D surface SAR sensor data. WIPL-D models have also been used to simulate the embedded and distributed sensors and to verify the significant enhancement in the received signal-to-noise ratio obtained by burying radiators under the surface.