Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!att!cbnews!military
From: GA.CJJ@Forsythe.Stanford.EDU (Clifford Johnson)
Newsgroups: sci.military
Subject: Infra-red detection
Message-ID: <12535@cbnews.ATT.COM>
Date: 22 Dec 89 06:03:41 GMT
Sender: military@cbnews.ATT.COM
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Approved: military@att.att.com



From:      "Clifford Johnson" <GA.CJJ@Forsythe.Stanford.EDU>
} > there is a large IR signature associated with heat
} Thermal radiation is emitted over a broad range of wavelengths . . .
} capabilities depend, of course, on the sensors, the targets of
} interest, and the background against which those targets are observed.

While not an expert, I believe the distance of the sensor from the
source is also important, especially because the atmosphere absorbs
radiation except at certain wavelengths.  Thus, viewed
from space, an oil fire has the same infra-red radiation pattern
as a missile exhaust plume.  Given this look-alike phenomenum,
the term "signature" is very misleading.

Are satellite sensors sufficiently sensitive to detect residual
differences in spectroscopic distributions as to reliably
differentiate between various hot sources?  I don't believe so.
Can anyone enlighten me?

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