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Solomon Islands intervention force



 
 
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  #21  
Old July 30th 03, 01:55 PM
RT
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matt weber wrote in message ...
On Sat, 26 Jul 2003 20:37:19 +1000, "RT" wrote:


matt weber wrote in message ...
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......

30 watts RMS is more than enought to disrupt most airborne radars.
remember the radar duty cycles are very very short, typically less
then .1%, so the ERP from 30 watts rms could easily be in the tens of
kilowatts.

Ground based fire control radars are another story. Those things
often have ERP's of several hundred megawatts. They are designed to
burn through almost any kind of intereference.



Erm... I DID say..:-
"I have a severe
problem believing 30 W in a UAV will disable your average

anti-aircraft/G-A
missile radar......"

Are you suggesting anti-aircraft/G-A missile radars are airborne?

Or do you think they might be "Ground based fire control radars" which
"are another story"?


Depends whose it is. The Russian and American Fire Control radars are
awesome beasts, however as you move to more locally manufactured
product, they start to look more and more like the capabilities of
airborne radars.


AFCS - what sort of a cop out is that? Are you suggesting the Solomons
have a home groan radar industry?

Sheeeeesh.......... Mattt, you stuffed up - admit it and let's go on with
something else.....


  #22  
Old July 31st 03, 05:08 AM
matt weber
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Posts: n/a
Default

On Wed, 30 Jul 2003 22:55:58 +1000, "RT" wrote:


matt weber wrote in message ...
On Sat, 26 Jul 2003 20:37:19 +1000, "RT" wrote:


matt weber wrote in message ...
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......

30 watts RMS is more than enought to disrupt most airborne radars.
remember the radar duty cycles are very very short, typically less
then .1%, so the ERP from 30 watts rms could easily be in the tens of
kilowatts.

Ground based fire control radars are another story. Those things
often have ERP's of several hundred megawatts. They are designed to
burn through almost any kind of intereference.


Erm... I DID say..:-
"I have a severe
problem believing 30 W in a UAV will disable your average

anti-aircraft/G-A
missile radar......"

Are you suggesting anti-aircraft/G-A missile radars are airborne?

Or do you think they might be "Ground based fire control radars" which
"are another story"?


Depends whose it is. The Russian and American Fire Control radars are
awesome beasts, however as you move to more locally manufactured
product, they start to look more and more like the capabilities of
airborne radars.


AFCS - what sort of a cop out is that? Are you suggesting the Solomons
have a home groan radar industry?

You never know who has been trading what with who. You can often be
surprised at how good indigenous engineering is as well. NEVER
UNDERESTIMATE the resources or persistence of a highly motivated
enemy.

If you asked someone what the odds were that an F117 could be shot
down by a soviet SAM 5 years ago, everyone would have laughed at you,
but a combination of smart indigenous engineering in Kosovo, and a
dumb USAF resulted in just that.

The US did indeed try fitting an airborne radar onto a AA gun, it was
called the Divad. It was a spectacular failure, and was cancelled long
before it ever got into volume production.

The really good Russian and US stuff is hard to get on the black
market, the not quite so sophisticated Indian, Chinese, French, North
Korean stuff is a whole lot easier (and cheaper) to get, and a whole
lot less capable.

  #23  
Old July 31st 03, 04:11 PM
phil hunt
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Default

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?



--
A: top posting

Q: what's the most annoying thing about Usenet?

  #24  
Old August 1st 03, 05:38 AM
matt weber
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Default

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. (Think about
why the AM radio hears the ignition noise on the cars as they go buy,
but an FM radio does not. Ignition noise is amplitude modulated, and
FM detectors do not detect amplitude.

Others are monopulse. they fire a single pulse. The next pulse they
fire will be on another frequency. There are all sorts of modulation
and transmission schemes to extract additional information from the
target, and to make the radar more difficult to jam. EF-111's and
EA6-B use the entire payload for Electronic counter measures.




This is why ECM system are so complex. To defeat the other radar
effectively, you have to figure out exactly what it is (and the USA
and it's allies have a long history is doing things to 'excite' the
air defenses of less than friendly countries so they can characterize
the radar, and build a threat library.

  #25  
Old August 1st 03, 05:58 AM
S. Sampson
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Posts: n/a
Default

"matt weber" wrote

This is why ECM system are so complex. To defeat the other radar
effectively, you have to figure out exactly what it is (and the USA
and it's allies have a long history is doing things to 'excite' the
air defenses of less than friendly countries so they can characterize
the radar, and build a threat library.


The big thing today, is to direction find (DF) the emitter and kill it.
Not a whole lot of jamming anymore except for self-protection.
The U.S. and British DF aircraft are very good at finding emitters,
and then the UAV's can go in and get a visual, and the plan made
for its destruction. The mobile stuff is not that hard to kill.

Even the Patriot was blown-up when it targeted the HARM equipped
aircraft in the recent war. Shoot first, and live.


  #26  
Old August 1st 03, 02:54 PM
phil hunt
external usenet poster
 
Posts: n/a
Default

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?

I would guess the radar uses a different "chirp" for each pulse it
sends out; is that correct?

(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.

but an FM radio does not. Ignition noise is amplitude modulated, and
FM detectors do not detect amplitude.

Others are monopulse. they fire a single pulse. The next pulse they
fire will be on another frequency. There are all sorts of modulation
and transmission schemes to extract additional information from the
target, and to make the radar more difficult to jam. EF-111's and
EA6-B use the entire payload for Electronic counter measures.


It seems to me the best way to counter a radar is to fire a missile
that homes in on the radar's signals -- since a radar, to work, must
emit signals.

(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).

This is why ECM system are so complex. To defeat the other radar
effectively, you have to figure out exactly what it is (and the USA
and it's allies have a long history is doing things to 'excite' the
air defenses of less than friendly countries so they can characterize
the radar, and build a threat library.


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.


--
A: top posting

Q: what's the most annoying thing about Usenet?

  #27  
Old August 2nd 03, 04:34 AM
matt weber
external usenet poster
 
Posts: n/a
Default

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.
  #28  
Old August 6th 03, 12:49 AM
Thomas Schoene
external usenet poster
 
Posts: n/a
Default

"M.R." wrote in message
u
Really interesting this evolution of UAV's and other weapons such as
JDAM munitions.
How do the JDAM munitions work? Is it and inertia launch then initial
GPS guidance and an infra-red image for the last stage to home in on.
If a UAV and JDAM weapon where combined that would have to be a fairly
stealthy target?


Current JDAMS are pure GPS -- no IR seeker. The weapon isn etirely passive
and certainly could be stealthy. The problem is that even the 500-lb JDAM
is really too big for current UAVs. Smaller bombs are in development, and
we may well see UAVs armed with them in the not-too-distant future.

--
Tom Schoene Replace "invalid" with "net" to e-mail
"If brave men and women never died, there would be nothing
special about bravery." -- Andy Rooney (attributed)





  #29  
Old August 6th 03, 02:31 AM
phil hunt
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Posts: n/a
Default

On Fri, 01 Aug 2003 20:34:07 -0700, matt weber wrote:

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...


Why would it need to be so big? Is it the receiving equipment, the
transmitting equipment, or the electronics in between that takes up
the space?

(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.


How much do real radars cost?

Certainly there are some radio transmitting equipments that are
cheap -- for example mobile phones and wi-fi stations -- and I'd
imagine that scaling up the transmitting powrer on such a device
would be too expensive either.

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.
[...]
If you are looking for an F4 or a B52, it won't be very hard,


That's exactly the sort of thing I had in mind (or an F-16 or
Tornado or F-22, etc, bascially any modern supersonic aircraft)

--
A: top posting

Q: what's the most annoying thing about Usenet?

  #30  
Old August 6th 03, 08:42 AM
M.R.
external usenet poster
 
Posts: n/a
Default

Really interesting this evolution of UAV's and other weapons such as JDAM
munitions.
How do the JDAM munitions work? Is it and inertia launch then initial GPS
guidance and an infra-red image for the last stage to home in on.
If a UAV and JDAM weapon where combined that would have to be a fairly
stealthy target?

Is it fairly easy to have a sensor that warns of overhead SAR from a UAV or
such.
Whats the difference between Synthetic Aperture Radar and just radar?
Is there any such thing as active infra-red or is infra-red solely a passive
means of detection. What's its range?

What's the formula for roughly working out the horizon of a radar?
Height in feet squared is the horizon in miles or something.
This new Surface Wave Radar blows it all out of the water.

"matt weber" wrote in message
...
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.



 




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