On Wed, 14 Jun 2000, Michael S. Lorrey wrote:
> I suppose most people are not aware of the sophistication of the newer
> systems. The newer systems do function passivly, but while they
Well, whether actively or passively, they are typically relatively
removed from an object they're detecting. If that object attempts to
camouflage as something natural, or blends into the background noise,
you're having a rather tough job detecting it.
> primarily work off of source transmissions, there are also some
> 'undocumented features': they also 'image' the 3D space of the ocean off
> of ambient diffuse sound, much as whales do. So they can spot any object
> of a given minimum sonic cross section. A metallic bouy actually
A large liquid baloon with a slow sound diffraction gradient, possibly
including foam at the core is not something which is intrinsically very
well visible on sonar.
> reflects quite well compared to soft animal flesh, which is the normal
> aquatic mammal target. Many whales echolocation capability is sensitive
Of course, the buoy would not want to be a good sound reflector.
> enough to sonically image an entire ocean off of one or two calls, and
> the newest mikes were privately developed specifically for studying
> whales, but the tech was seized by the Navy at the patent orifice. So
A whale is either large, or loud, or both.
> unless you grow your bouy out of a meat vat, your bouy is gonna stick
> out like an 18 wheeler on a Nevada highway patrolmans radar scope...
Don't thunk so. It's easy enough to camouflage a floating smart nuke (the
only problem will be orientation, which would require a teensy floating
GPS antenna on a tether).
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