An Elegant Active Sonar Countermeasure
Sven Gelbhaar
6 September 2008
As I’m sure we’re all aware, the current method for active sonar scrambling
is to deploy a physical buoy that emits vast quantities of sound, unless of
course the technology has advanced beyond what Hollywood is portraying. I
would like to suggest a much more elegant alternative that won’t require
the expulsion of physical objects which need to be replaced every time you
use them.
For a little background on the state of sonar as it is today (or at least
the unclassified elements of it) I encourage the reader to refer to the
great fount of human wisdom known as wikipedia. The relevant literature
can be found at: http://en.wikipedia.org/wiki/Sonar. The reader will note
that no mention is made of the obvious countermeasure wherein the object
being ‘pinged’ simply sends an identical ping back to the source a couple
of seconds later. This would, in effect, confuse the sonar operator and/or
system as to the distance of the subject it’s looking for, provided that it
was sending more than one concurrent ping as in the case of homing
torpedoes.
What’s of especial note is that by sending one-for-one ping replies to the
point of origin, the estimated distance to the target should be
approximately half of what it is in reality; which would lead the torpedo
to exploded twice as far away from its intended target as it was programmed
to, giving the employing submarine a much greater life expectancy than it
has now.
Presuming that there is an optimal range of infra-sound (which I’m sure
varies based upon water density, mainly temperature and depth), it isn’t
much of a stretch to suppose that all implementations of sonar are pretty
much identical, so the clever sub commander can instruct his sonar operator
to mirror ping for ping with no capital invested whatsoever. An automated
system based upon this principle could be cheaply developed as well for
sheer convenience, and to ensure that acoustic properties are matched
perfectly.