On Fri, 1 Aug 2003 14:54:31 +0100, (phil hunt)
wrote:

On Thu, 31 Jul 2003 21:38:38 -0700, matt weber wrote:
On Thu, 31 Jul 2003 16:11:48 +0100, (phil hunt)
wrote:

On Fri, 25 Jul 2003 22:44:02 +1000, RT wrote:

The Raven wrote in message ...
My only concern is that the Aerosonde UAVs will be over hyped to the point
people will get the wrong impression of what they are and what they are
capable of.

Yair. Well.

Not helped by the hype on the Aerosonde web site rabbiting on about its
radar disruptive capabilities - shortly after saying the total power
available is 30 watts or similar. It's not my field but I have a severe
problem believing 30 W in a UAV will disable your average anti-aircraft/G-A
missile radar......

Why?

Couldn't the UAV check for radar emissions, and then broadcast a
signal on the same frequency the radar is using? wouldn't that
disrupt the radar?

Depends upon the type of radar. There is very little 'CW' radar in
use anylonger. most is "chirp" frequency modulated, so if you don't
appropriately modulate the signal, it is simply ignored.

That makes sense. How easy would it be for the UAV to listen to thre
incoming signal, and match its response to it?
The Self Projection jammer pods often represent more than the
available lift capacity of the UAV unless you are talking about
something the size of a Predator or a Global Hawk...

I would guess the radar uses a different "chirp" for each pulse it
sends out; is that correct?
It may, but more likely it is a mono pulse, same chirp, but broadcast
on a different frequency each time...

(Think about
why the AM radio hears the ignition noise on the cars as they go buy,

I can't say I've ever noticed that effect, but I'll take your word
for it.


(Of course, an adversary could build lots of cheap boxes that give
off signals that appear the same as a real radar, to soak up lots of
anti-radiation missiles).
While it could be done, it isn't all that cost effective, to build an
emitter that would look enough like a real radar to be attacked would
probably cost 15-20% of the price of the real thing. That's a lot of
money to spend on decoys!
How good are passive sensors compared to radar? I would imagine that
visual light and infra-red would be quite good ways of detecting
aircraft (and if you have 2 detectors some distance away you can use
triangulation to get the exact position), at least when there are no
clouds.
Depends upon what you are looking for. At fair amount of effort has
gone into reducing both the RF and Visual 'cross section' of aircraft.
A great deal of effort has also gone into reducing exhaust gas
temperatures. You can actually hold your hand in the exhaust stream of
an AH64 Apache while the engine is at idle.

If you are looking for an F4 or a B52, it won't be very hard, it is
big, noisy and smokey. If you are looking for a 100kg UAV at 5000
feet, or a Proteus at 70,000 feet... good luck... one of the reason
sat links are preferred is they only radiate energy upward, so they
don't provide much to listen for from the ground.