Archive for Friday, May 29, 1998


May 29, 1998


For those seeking unobtrusive methods of exploration into the earth, ``radar'' is more than just a character from M*A*S*H or a way to detect incoming aircraft.

Generally speaking, the term ``radar'' is an acronym for radio detection and ranging. Radar is used to detect remote objects through radio waves. Ground-penetrating radar, like the name suggests, uses waves that pass through the ground, hit a remote object and bounce off the surface. The waves -- which can pass through air, water, soil and even concrete -- are sent and received through antennas and converted into images on a computer screen.

There are two types of radar systems: pulse and continuous wave. Pulse-radar systems transmit pulses of electromagnetic waves, usually microwaves, that help researchers determine how far an object is from the radar source.

Continuous-wave, or Doppler radar, can be used to figure the speed of an object.

For more specific investigation, electrical engineers design radar systems that operate on various electromagnetic-wave frequencies.

One set of frequencies may not detect dense objects near the surface, such as land mines, but may be ideal for detecting a less dense, deeper object, such as a pocket of oil seeping from an underground tank. Also, certain soil types, known as "lossy,'' cause energy to weaken and dissipate as it passes through.

Considering these factors, engineers design ground-penetrating radar for various ventures by combining hardware, wave frequency and computing software.

-- Matt Gowen's phone message number is 832-7222. His e-mail address is

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