*** Ground Penetrating Radar ***

Thu Dec 15 00:47:53 1994
Letter  : 2993399    From: Search & Rescue Info
Address : SARINFO@mindlink.bc.ca
Subject : Ground Penetrating Radar
Bytes   : 2480

To: sarinfo@mindlink.bc.ca

Martin,

An article in the Nov. '94 issue of "High Mountain Sports" magazine features an
article on the use of ground penetrating radar for locating victims buried by
an avalanche.  This sort of thing falls right into the realm of the SAR
Technology Advisory Committee.

The article detailed a case that involved the use of such equipment to search
for a body that had been missed by all conventional avalanche search
techniques, from dogs to probe lines etc., on a mountain in Scotland.  The
equipment was used after these techniques had failed during the months after
the accident and new fall snows threatened to prevent the body from ever being
recovered.

It was flown in by helicopter and assembled on site.  The search area was laid
out with grid lines prior to the search to ensure efficient and thorough
coverage.  Just two hours was required to find the body, what with it being the
first actual use of such equipment for that purpose, and with a skeptical crew.
Here is some of the technical information:

- The hardware consisted of a console "the size of 2 tv sets", and an antenna
on the end of a cable. The console remained stationary while the antenna was
moved through the search pattern.

- the system operates at 300 or 500 MHz (different antennas, 500 MHz preferred)

- Ice has a dielectric of 4, whereas bones have a dielectric of 13.  Soil is
12-30 so the conditions were actually ideal and the detection definitive. The
body stood out clearly.

- no details given of weight or power requirements

- doubtful if the avalanche debris contained any trees, etc. I don't know if
such debris would interfere with its use

They felt that the technology proved itself and it has a definite future.  They
feel the equipment can be reduced in size to make it more portable and training
in its use would only take a few hours.  I think we definitely need to examine
this technology as a potentially beneficial application, with an eye towards it
eventually being used in the first response to an avalanche burial.

As a side note, I had inquired of John Ward at SAREX wether the RCMP FLIR could
possibly be used to detect  buried subjects.  There is no data on the
effectiveness of this ( he seemed eager to run such tests ) and theorized that
its effectiveness diminishes with the passage of time and the cooling of the
subject, and the depth of burial.  Ground penetrating radar seems to hold more
promise.

-Bob Manson
00:12  12-15-1994