Experimental Demonstration of Underground Structure Characterization Using Sensitive Magnetic Sensors.

摘要

The practical feasibility of detection and characterization of underground structures using electromagnetic sources in the ELF/VLF range is being investigated. For this, we investigate issues associated with sensors. One important objective is to examine the feasibility of using magnetic field measurements alone. We have developed unique 3-D e.m. models which can adequately cover arbitrary geometries, inhomogeneous ground, various excitation schemes and most importantly can handle a wide range of frequencies. We are currently performing numerical simulations using the 3-D e.m. code. We have established the need of 3-D modeling and there are no other codes which allow complete solutions for e.m. problems without any approximations. The results of these simulation will provide the experimental requirements. It is impractical to measure E fields from a stand-off distance. We are pursuing simulations to see if only the magnetic field measurement could provide the desired information. We have developed the most sensitive magnetic sensors which can be used from a remote location (such as from UAV). We plan to use these sensors for practical demonstration of magnetic-field-only measurements.