On Fri, 17 Oct 2003 23:57:18 -0600, Scott Ferrin wrote:
On Sat, 18 Oct 2003 05:13:12 +0100, ess (phil
hunt) wrote:

On Fri, 17 Oct 2003 23:49:37 GMT, Thomas Schoene wrote:
"phil hunt" wrote in message
rg
On Thu, 16 Oct 2003 13:14:32 -0600, Scott Ferrin
wrote:

That's assuming the Typhoon can detect an LPI radar.

What's that, and how is it different from other radars?

LPI = Low probability of intercept. Usually a psuedo-random spread-spectum
signal that looks like random noise to a typical radar warning receiver.

Do you (or anyone else) have any estimate on how effective this is?

Here's something from Gulf War 1. In the book Gulf War Debrief by
Airtime Publishing they were interviewing a Tomcat pilot. He made the
comment that whenever the Iraqis detected a Tomcat's radar they'd
split but they never seemed to react to the F-15s (F-15s got the
majority of the kills, Tomcats got a chopper I think). Later I read
that the F-15s that went to the Gulf had LPI radars.

That suggests to me that the radars that Iraq had in 1991 counldn't
detect LPI radars. However, Iraq didn't have the best radars in the
world not even then, and the electronics industry is more advanced
today than it was (12 years is roughly 6-8 doublings of
performance/price, according to Moore's law). How effective would a
modern LPI radar be against an adversary using detectors which are
roughly as sensitive? Bear in mind that it's output signal cannot
truely look like random noise (it must be stronger, or the receiver
wouldn't be able to do anything useful with it). Also, the signal
reaching the receiver will be billions of times weaker than the
signal reaching the target. It therefore follows that the signal
reaching the target *at the relevant frequencies* will be billions
of times stronger than background random noise.

I suppose the question I'm asking amounts to: assuming equal
technology on both sides, can radar signals (from an aircraft radar,
or ground-based radar) be detected by an aqdversary (e.g. either an
aircraft, or anti-radiation missile)? Obviously when there's a wide
technology disparity, the answer to the question becomes most
obvious.

BTW, does anyone know of a good web resource on radars? (Most of the
stuff I can find from Google is a bit basis).

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