Good things to know when dialing with enemy missiles. ..

[volk-19]

I was practicing to decoy the missiles in Lock On and found it hard to do. I did a research on “Missile Countermeasures” and found some good stuff. I hope you will find it useful.

Chaff Illumination

Chaff denotes small strips of metal (or glass fibres coated with metal) which are cut so that their length equals half of the wavelength of a radar's signal. This makes each piece a dipole antenna with quite impressive reflecting properties. As the history of radar has shown, chaff is quite successful against an unsophisticated radar but nowadays is rather limited in its efficiency if applied in its pure form.

 

But things are different if an aircraft under attack launches a chaff cloud and an on-board rearward-pointing antenna starts re-transmitting an incoming radar signal at it. That is, the chaff cloud is used as a mirror (a very blurred mirror, but a mirror), and the missile-seeker is presented with a strong false target and will switch over to homing in on the brightly-lit cloud of chaff.

 

 

 

 

Rapid Bloom Chaff (RBC) creates a "cloud" to decoy a missile (Courtesy aerospaceweb.org)

Radar chaff is a passive electronic countermeasure in the form of metal strips that are ejected either from an aircraft, ship or rocket. Chaff is ejected from an aircraft, much like a flare, and it creates a cloud of material that looks like a big radar target to an RF missile. The missile either goes after the larger target, or the target can be obscured by the cloud of chaff.

 

Chaff was first used during World War II when the Royal Air Force, under the code name "Window," dropped bales of metallic foil during a night bombing raid in July 1943. The bales of foil were thrown from each bomber as it approached the target. The disruption of German AAA fire control and ground control intercept (GCI) radars rendered these systems almost totally ineffective. Based on this early success, chaff employment became a standard bomber tactic for the rest of the war.

 

 

Another good link…..

 

http://www.aerospaceweb.org/question/electronics/q0191.shtml

[volk-19]

Now, here is an interview, with someone, who probably has experience in air combat.:smilewink:

America Strikes Back: Inside Look at War on Terrorism from the Air

Aired October 10, 2001 - 10:50 ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

 

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

MILES O'BRIEN, CNN ANCHOR: A lot of talk about this war against terrorism being an unconventional one. But at least in its early stages, this air war against targets in Afghanistan looks a lot like previous ones. Some of it is, well, almost paint by numbers if you will.

 

Joining to talk a little bit more about the first stages of any war is retired General Don Shepperd. He has a lot of experience in fighters, and can give us a sense of what the first targets might be.

 

In this case, you go after the things that might should you out of the sky. I guess that should be obvious.

 

GEN. DON SHEPPERD, (RET.) CNN MILITARY ANALYST: That's right, miles, the integrated air-defense system is what you are after in the beginning.

 

O'BRIEN: Let's do a sort of an a, b, c. This is not a how to, if you will. We don't want to do that kind of thing. But we want to give you a general sense of some of the principles involved in any early stages of any air campaign. Take a look at what's going on potentially in a situation like this. We have highlighted Kabul in Afghanistan. And let's bring you down a little closer and give you a sense. Early-warning radar and F-16 or F-15 coming in. Give us a sense of that.

 

SHEPPERD: Well, basically what happens here is the early-warning radar is the first thing to pick up aircraft approaching the country. They put out energy. It's reflected back to the site. They start to know that an airplane is coming, not much information yet.

 

O'BRIEN: All right, and then the next step, once that early- warning radar in play, what happens next?

 

SHEPPERD: Through landlines, the early-warning radar will tell the missile site to begin tracking, and aim their tracking radar in the vicinity of the airplanes. They then track it, and they also turn on the red here, which is a missile-tracking radar before they fire the missile itself.

 

O'BRIEN: So, so far, there are three radar devices involved, so far.

 

Next step in this process, the firing of a surface-to-air missile. What happens then?

 

SHEPPERD: In this case, the surface-to-air missile is fired at the airplane. You can see it fired and you watch it tracking at you, and gets pretty exciting in the cockpit at this time.

 

O'BRIEN: What are you hearing in the cockpit?

 

SHEPPERD: You are hearing a radar-warning receiver that tells you what's coming and where it's coming from. You turn on your own electronic-jamming pod. You throw out chaff. The whole idea is to decoy the missile toward the chaff and then stay away from missile, which has a warhead that can explode on proximity within about 300 feet.

 

O'BRIEN: All then, that black cloud we saw was chaff. It's just aluminum particles...

 

SHEPPERD: Aluminum particles.

 

O'BRIEN: ... send a surface-to-air missile astray.

 

SHEPPERD: Exactly, the missiles homes on the chaff instead of our airplanes.

 

O'BRIEN: Pulling a few Gs in a maneuver like this.

 

SHEPPERD: Indeed.

 

O'BRIEN: All right, let's go the next step here now. Now this a more coordinated approach to the whole thing. We sort of gave you a hypothetical, which isn't really true to form, because you're not talking about one aircraft. It's different.

 

SHEPPERD: Right, a lot more airplanes involved, and by the way, you could have several early-warning sites and three or four missiles shooting at you the same time. All of these are radiating. Now an electronic-jamming aircraft shows up and starts to jams the radars. The radar operators are now confused. Bad things showing up on their scope, their trying to work through it. And the next thing that happens is the following airplane shows up, and this is what we call a SEED, a suppression (UNINTELLIGIBLE) air defense airplanes, and he fires a radar homing missile, a high-speed antiradiation missile that homes in on the radar to take out the missile sites.

 

O'BRIEN: All right, so the issue here is you have a jamming plane. This is your primary, I guess, decoy plane, because it would get things going in some sense, right? Not really, this is not a decoy necessarily . It's an airplane that's trying to get to a target while these people are trying to prevent him from it.

 

SHEPPERD: All right, great. That's General Don Shepperd, giving us a sense of how these sorts of situations occur.

 

Let's take a quick look at some of the bomb damage assessment photos, if you will. That's what they call them, and those give you a sense of some of the targets. First of all, surface-to-air missile installation, this is typical layout here, isn't it?

 

You see those spokes that coming out of there. These are typically guns that are protecting it, correct?

 

O'BRIEN: This is SA-3 site. In the middle, the large thing is the radar, the low-blow radar. The three sites are the missiles, on transporters, erectors, launchers or tells. Each one of them has three missiles on there. The heart is the circle there, which is the radar. You want to take it out first, then the missiles.

 

All right, let's see the after picture and we'll give you a sense of what happened.

 

Looks like a successful one, doesn't it?

 

SHEPPERD: Yes, looks to me like it's all like all blown away. Probably one B-2 sortie targeting on all four of those intended points of impact.

 

O'BRIEN: Once those radar sites, those surface-to-air missile sites are down, you are able to engage in other targets, and of course chief among them airfields.

 

SHEPPERD: Exactly.

 

O'BRIEN: Give us a sense of the airfields that they would have gone after, and exactly -- this is typical airfield here. This particular one is in Shindand, and take a look at these craters here. And it Doesn't look like damage from here, but this is going to will shutdown this airfield, isn't it?

 

SHEPPERD: It really is. What you've got here, this is south of Herat, and basically the airfield there, the impacts are designed to keep airplanes from being able to taxi to, or land on, or operating from the runway. They can be repaired fairly quickly, so that we can take the airfield and operate from it, or it can be rebuilt for humanitarian purposes or the use of the Afghan people after the war.

 

O'BRIEN: So far, general, this has the feel of the early days of the air war over the Gulf. Things are going to start to change rapidly, aren't they.

 

SHEPPERD: It's a microcosm of the Gulf. Next perhaps comes some ground operations that we've been talking about early this morning.

 

O'BRIEN: But that's where things will depart from what we're familiar with, if you're using the Gulf as an example.

 

SHEPPERD: Exactly.

 

O'BRIEN: So far, when you say, the Pentagon says "air superiority," what does really mean?

 

SHEPPERD: People get the idea that air superiority, nothing will happen anymore in the air. What it means is you can operate around- the-clock, both day and night, and it's still very dangerous. A missile can show up at anytime, and you want to stay at high altitude, out of the guns, out of the shoulder-fired missiles, so it's still a sky in Afghanistan, even though we can operate at will, anytime of the day or night we wish.

 

O'BRIEN: All right, some important context and depth here.

 

TO ORDER A VIDEO OF THIS TRANSCRIPT, PLEASE CALL 800-CNN-NEWS OR USE OUR SECURE ONLINE ORDER FORM LOCATED AT http://www.fdch.com

[D-Scythe]

Mostly everything you stated applies only to older missiles. Newer radar missiles like the R-77, AIM-7M or AIM-120 use doppler to track and home in on a target, which are relatively immune to chaff unless the chaff cloud is directly between the target and the missile.

[volk-19]

Newer radar missiles like the R-77, AIM-7M or AIM-120 use doppler to track.....

 

 

What is DOPPLER?

[Weta43]

Doppler - You know when you hear a race car or a fast train coming towards you & the pitch is higher as it approaches then drops & is lower as it goes past & heads away - that's doppler shift. In radar, by measuring how much the reflected radar is pushed up or down in 'pitch' as it is reflected, you can work out if the reflector is approaching or receding - & how fast, & can also tell what reflections are from objects not moving relative to the earth & filter them out.

[Pilotasso]

Mostly everything you stated applies only to older missiles. Newer radar missiles like the R-77, AIM-7M or AIM-120 use doppler to track and home in on a target, which are relatively immune to chaff unless the chaff cloud is directly between the target and the missile.

 

I read numerous times that this is not the way to eveade in LOMAC and it should be needed to beam the launcher to make the chaff trail look like part of the aircraft. Droping cahff from behind or frontal attacks only propmts the missile to keep flying torwards the target anyway.

[GGTharos]

In LOMAC the missiles do not do doppler discrimination (yet) though they can be notched. Once this is corrected, head-on chaff use will be ineffective.

[Pilotasso]

I like the way you said "yet" :D

[GGTharos]

Hehe. ;)

 

I think these sensor things will be corrected in TK or fighter ... so a while to go still unfortunately.

[volk-19]

So, you guys saing that chaff is ineffective against AMRAAM (R-77, AIM-120) missiles in reality?

[D-Scythe]

I read numerous times that this is not the way to eveade in LOMAC and it should be needed to beam the launcher to make the chaff trail look like part of the aircraft. Droping cahff from behind or frontal attacks only propmts the missile to keep flying torwards the target anyway.

 

Well, chaff doesn't really ever "look" like the target - it's RCS for one is usually several orders of magnitude larger. Rather, chaff is used mostly to introduce noise to the tracking radar (in the case of a look-up engagement - in a look-down engagement, both it and the ground provides clutter/noise for the missile to deal with).

 

Putting a chaff directly between the target and the missile (only possible in a tail-chase scenario) sorta "blinds" the radar IIRC. I'm sure GG will clarify.

 

Volk, the answer to your question is no, chaff really isn't all that effective against doppler missiles except in some "special" situations. Beaming the missile and forcing the radar to "look-down" is one of these "special" situations ;)

 

Speaking of which, the "beaming+chaff" maneuver might not work on smarter missiles like the AMRAAM, which may have some special algorithms programmed into it to (try to) defeat such a maneuver which has been around for a good 30 years already. Although it'll probably take another 30 years before the public finds out for sure if this is true.

 

Either way, I think the target's best bet when faced with an R-77 or AIM-120 is try to defeat the missile kinematically, as from what I've read it doesn't seem very safe to wander into their no-escape zones at all (unlike how it is currently represented in LOMAC).

[AerialHawk]

So, you guys saing that chaff is ineffective against AMRAAM (R-77, AIM-120) missiles in reality?

 

Let's not even go on that subject. We all know there are people here who will talk and talk about "my amraam is best", claiming statistics like "the RL amraam has a 90~100% hit ratio" without any proof. Even worse, certain people want OTHERS to post proof to back up their claims, but THEY will not post ANY and will get away with it with a simple "bla bla i had declassified documents years ago that showed..." or "i know someone/i have a friend that..." :megalol:

 

You know who you are.

[GGTharos]

Sheesh AerialHawk; some of us -try- to find these things out, and we can't always put our sources in a link. :P

 

D-Scythe is basically right. Chaff causes a 'look down' situation for a radar when you use it while above the threat radar, and more clutter in a look-down situation.

 

From speaking with a real fighter pilot I have been lead to believe that not only chaff is not very effective against AIM-120 and R-77, but it is also not very effective against any modern SARH missile.

 

This means chaff can still work, but only in special circumstances, for example:

 

When used on the beam (so doppler discrimination is bad)

When used with some forms of ECM

When used in -enormous- quantities to create a 'chaff blanket' that will reflect so much energy back to the radar that the target will not be distinguishable from all this noise (fighters do not carry enough chaff to do this - special drones are used for such things)

When used between radar and aircraft (same as chaff blanket)