Accession Number:

ADD005105

Title:

Method for Determining Changes in Earth Resistivity by Measuring Phase Difference Between Magnetic Field Components.

Descriptive Note:

Patent,

Corporate Author:

DEPARTMENT OF THE NAVY WASHINGTON D C

Personal Author(s):

Report Date:

1978-03-14

Pagination or Media Count:

4.0

Abstract:

Method and apparatus for detecting tunnels beneath an area of the earths surface wherein an oscillator couples a current into a linear conductor at the earths surface to generate a magnetic field in the earth beneath the area. Phase angle measuring means measures phase difference between the vertical and horizontal components of the magnetic field at selected points along a line parallel to the linear conductor to detect abrupt changes in earth resistivity, changes in resistivity indicating the presence and horizontal position of a tunnel. Author

Subject Categories:

  • Magnetic and Electric Field Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE