ELF/VLF Electromagnetic Detection and Characterization of Deeply Buried Targets

We propose to provide a numerical capability to map the ELF/VLF electric and magnetic fields above the ground, as perturbed by threat underground structures of interest to the DoD. MATLAB source code will be delivered that will produce these perturbed fields as a function of radio frequency, as well as values for the unperturbed background field and the external noise. The latter two signals are the primary limiting factors to the sensitivity of any low-frequency surveillance system. Two sources will be employed in the calculations of the perturbed fields: 1) distant HAARP/HIPAS low-frequency modulated signals; 2) a local source, for example from a coil near the surveillance area. This phenomenological capability is sorely lacking at present, as various sensor and surveillance concepts are being designed and offered for subsurface monitoring. There is little basis for assessing feasibility or performance effectiveness among proposed candidates. The MATLAB package we will deliver will be comprised of extensive tools our company already has in place, modified and adapted to handle subsurface DoD threat objects and the above two radio signal sources. Example calculations will be provided to demonstrate how the code is used, and to give feasibility estimates for the most obvious system implementations of such sensors. The output of Phase I will form the basis of the Phase II effort to: a) design, model, prototype, and test and ELF/VLF sensor, and b) use ELF/VLF field maps to examine the methodology for inverting/extracting information about underground structures.