Newsgroups: sci.military.moderated
From: Bill Gawne <gawne@rosserv.gsfc.nasa.gov>
Subject: Re: Night vision question:
Organization: NASA Goddard Space Flight Center -- Greenbelt, Maryland USA
Date: Fri, 3 Nov 1995 17:59:38 GMT

Neal.I.Mitchell@Dartmouth.EDU ("The Albanach") asked:
>What are the different types of night detection devices in use by the
>more modern military nations today?

1. Thermal Imaging systems, which are sensitive to infrared light. Typically
in the 8-12 micron region, though some operate in the 3-5 micron region.

  These systems generally use some kind of semiconductor arranged as a
  focal plane array, sensitive to the IR light of interest.  Circuirty is
  used to convert the IR image into a visible light display.  Thermal
  imaging systems include FLIR, tracked vehicle thermal sights, etc...

2. Low light enhancement systems (eg. 'starlight' scopes), which are
sensitive to visible light and the very near infrared.

  These systems generally use some kind of photomultiplier tube arrangement
  to significantly increase the brightness of the available light.  More
  modern systems take advantage of things such as microchannel plate design
  to acheive greater light enhancement in smaller packages.  Low light
  enhancement systems include the AN/PVS-5, AN/PVS-7, AN/VIS-6 night
  vision goggles, and various kinds of starlight scopes.

3. Millimeter wave radar, sensitive to light in the very far IR, and
very short wave radio waves.

  These radars operate at wavelengths much shorter than normal radars,
  and are thus capable of imaging human sized targets.  They are large,
  and thus not useful as personal gear.

>Please explain why/how Night Desert Camo patterns and chemicals in
>BDUs lower the chance of night scope detection?

  The grid on the gridded clothes interferes with the grids of many low
  light enhancement systems.  The chemicals cause heat leaving the body
  to be re-emitted at longer wavelengths where thermal imagers are less
  sensitive.

>Tactically speaking, what can the average infantryman/mechanized unit
>do to lower the chance of being detected by aggressor forces using
>these night detection devices? 

  Don't skyline yourself.  The thermal systems can be confused if you
  appear against a background of the same temperature.  You show up
  much better against a background of air, as opposed to a thermally
  'noisy' background of rocks and dirt.

  Against forces using low light enhancement devices, wear the night
  camoflage patterns and be careful of movement.  Also, try to move
  directly toward opposing forces, since these devices have essentially
  *no* depth of field.

>Are there current publications on this subject?

I don't know about military publications that would be available for general
sale.  There was a Night Enhancement Systems book written a few years ago
for Marine Corps Studies and Analysis that I was involved with, but I doubt
it's generally available yet.  There is a good body of research literature
on night vision systems, including the annual proceedings of the conferences
of the SPIE.  (Pretty technical stuff, that.)  There's also the Navy Research
Lab's excellent Infra Red Handbook, though again it's a very technical tome.

(copy to Neal Ian Mitchell)

-- 
-Bill Gawne, MSgt USMCR(Ret)
The nation continues to invest in a Marine Corps based in large part on
its confidence that Marine forces will prevail, even under the most 
demanding circumstances.                      - Introduction to FMFM 1-2