This proposal addresses the design of a low frequency airborne earth penetrating radar which will detect buried objects and earth cavities (as contrasted to imaging them). It uses low directivity loop-dipole antennas, ground clutter cancellation through frequency diversity and possibly lobe switching. It might also detect radar camouflage. We also propose .01 scale model experiments to search for submerged objects from the air over a tray of salt solution. An appendix where we develop the equations needed for the scale model also shows that the ground conductivity is critical in determining the frequency at which such a system can operate. Ranges of earth conductivity from the literature are given, but we also propose a search for better data and the design of experiments to collect such data from the air in regions of military interest. A notable feature of the proposal is its emphasis on the basic limitations of earth penetrating radars. A two volume final report is offered. One volume will be devoted to these basic limitations, tradeoffs and sensitivity analysis. It will be self contained, in readable form, intended as a reference and starting point for further work and management decisions in this subject area.Anticipated benefits/potential applications:Locating near surface underground features such as springs, ruins and old streambeds. Archaeologic features such as stone structures also represent differences in conductivity and might be located by such a device. It is also conceivable that, with progress in electronics, the concept could be implemented in hand held devices such as those now used to find lost coins, ring and other conducting objects in sand beaches.
