Accession Number : ADD015074

Title :   Pulsed Field System for Detecting the Presence of a Target in a Subsurface Environment.

Descriptive Note : Patent, Filed 23 Apr 79, patented 18 Jun 91,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Ramstedt, Clarence F

Report Date : 18 Jun 1991

Pagination or Media Count : 8

Abstract : In a method and apparatus for searching a subsurface environment to detect the presence of a target therein, an electromagnetic field is emitted which comprises successive electromagnetic pulses of selected duty cycle, the time interval between pulses comprising a zero emission interval and a sampling interval, the sampling interval following the zero emission interval, and the polarity of the pulses of the emitted field alternating at a selected alternating frequency. The emitted field is projected into the environment from a selected location, and the electromagnetic field proximate to the selected location is sampled during each of the sampling intervals to provide a train of proximate field samples. The train of proximate field samples is spectrum analyzed to determine whether or not the field proximate to the selected location contains a component having a frequency which is equal to the alternating frequency. (Author)

Descriptors :   ELECTROMAGNETIC FIELDS, ELECTROMAGNETIC PULSES, ENVIRONMENTS, FREQUENCY, INTERVALS, POLARITY, PULSES, SAMPLING, SUBSURFACE, TIME INTERVALS

Subject Categories : Magnetic & Electric Fld Detection & Detectors
      Active & Passive Radar Detection & Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE