Copy IDA DOCUMENT D-1457 ON THE FEASIBILITY OF USING EXTREMELY LOW FREQUENCY ELECTROMAGNETIC FIELDS TO DETECT MINES IN SHALLOW WATER

This document considers an approach to mine detection based on electromagnetic detection. It involves the use of a magnetic or electric dipole antenna to transmit a low frequency signal that would illuminate and interact with an object, such as a mine, all dimensions of which are small compared to the wavelength as well as to the distance between the object and the antenna. A dipole antenna, which may be the same as or different from the transmitter, would receive the signal due to the interaction of the illuminated body with the incident electromagnetic field. Past analyses have demonstrated the feasibility, even at fairly long ranges, of using blue-green lasers to detect bodies immersed in pure water. Unfortunately, this detection method fails in turbid water, which is not transparent to the short wavelength laser radiation, and in cases where the mines have become buried. Sonar techniques, while useful in deeper water, also have problems in the shallow water regime because of clutter and reverberations.