Low AAM PK .. Oh no not that again...

[tflash]

The only difference between and ARH and SARH is the illuminating platform. There's no reason why the SARH missile seeker cannot lock onto the chaff instead of the aircraft. It is a SEPARATE SYSTEM. It isn't just YOUR radar that has a lock, it is a missile's seeker also. you can try to defeat either.

 

 

I am very sceptical about that claim, GGTharos. The missile seeker is tracking the reflected energy from the fighters RADAR. This is a steady, intensive beam (this is the whole point of STT). Chaff can momentarily break the steady return to the fighters radar, by having a big reflection - in ALL directions: the NOISE makes it impossible momentarily for the painting aircraft to gain the reflection. The whole idea is that this could cause a break in lock.

 

IF breaking the lock FAILS, my guess is the fighter RADAR continues to paint the real target with high energy, this being returned. It is this beam the SARH missile keeps following The SAHR missile at that point is not homing in on a mere NOISE source like the chaff cloud, which is reflecting the energy in all directions an thus has MUCH lower intensity.

 

You seem to imply on the other hand that chaff does not work on the NOISE principle, but on the return principle, i.e. that it produces a larger and better lockable echo, which is clearly different.

 

I still think that if you have lock, your SAHR missile will track the real target.

[peterj]

The only "monkeys" piloting Flankers in Africa were Russian instructer pilots and soldiers, if that's what you're referring to. You should be more careful of what you say.

That's not the picture I was getting reading this: http://www.acig.org/artman/publish/article_189.shtml

 

"At the same time, a group of Eritrean pilots went through a kind of crash course in the Ukraine, in order to learn how to fly and use new MiGs and Mils."

"The initial group of EtAF Su-27-pilots were trained at Debre-Zeit by Russian instructors."

"Both Sukhois, flown by Ethiopian pilots, detected the appearance of their opponents in time and attempted to disengage, when - all of a sudden - they came under an attack by several R-27/AA-10 missiles."

[Yellonet]

But if we're talking about monkeys in the cockpits in Africa,it's ok :)

That doesn't belong here nor anywhere :icon_evil

[D-Scythe]

Sorry to come that far back, but a few thoughts on this :

Your missile seeker in a SARH is seeking the return signal coming from the target locked by the illuminator. The reason why it won't lock on a chaff without the illuminator locking on the chaff is simply that the chaff don't emit any signal. It won't lock on something it can't even "see".

Your SARH signal is locked on a "return-signal" (with specific signature), not on any object in its FoV, even less a passive object.

 

So to spoof a SARH, you HAVE TO spoof the emitting radar, ie radar of the launching plane.

 

Vs ARH, you have to spoof the missile itself, because the missile is the illuminator. In fact, in both case, you're spoofing the illuminator, forcing it to lock on the wrong thing. You can't force the missile seeker to watch "something else" than the return-signal from the illuminator, AFAIK

 

Well, perhaps you can, in fact. See Jane's FA-18 for this, FA-18 E seems to carry a ECM decoy built specifically for that purpose, "create" a return signal offset from the real target plane. Or perhaps they only create additionnal noise to spoof the illuminator once more, but the fact that they are used carried in the back of the plane several meters away seems to suggest that they try to force the radar/seeker to watch "the wrong thing".

 

 

Now, is the missile illuminator more prone to lock on a chaff than an aircraft illuminator, I don't know. There's a big range difference to take into consideration, ARH on-board radar locks really closer.

 

You've got it completely wrong. In SST, the radar beam isn't "thin" enough to just illuminate the target - it usually illuminates a lot of other things AROUND the target as well, including chaff. Thus, the SARH missile can be spoofed by chaff even though the illuminating radar isn't.

 

ARH missiles are actually better in this respect, because although it has a wider FOV than the illuminating radar, it's much closer to the target, thus the diameter of its own radar cone is much smaller. Therefore, it illuminates LESS things around the target, including LESS chaff (actually, chaff just moves out of the FOV faster - IRL, it doesn't matter if you release one chaff or 5 chaff, although it does in Lock On).

 

The only instance where an SARH missile might prove more effective than SARH missiles is when the missile is in a look-down situation, but the illuminating radar is look up. In that case, the ARH missile still has to contend with ground clutter whereas an SARH missile does not. In any other scenario, SARH missiles are either equally effective or less effective than ARH missiles.

[D-Scythe]

That's not the picture I was getting reading this: http://www.acig.org/artman/publish/article_189.shtml

 

"At the same time, a group of Eritrean pilots went through a kind of crash course in the Ukraine, in order to learn how to fly and use new MiGs and Mils."

"The initial group of EtAF Su-27-pilots were trained at Debre-Zeit by Russian instructors."

"Both Sukhois, flown by Ethiopian pilots, detected the appearance of their opponents in time and attempted to disengage, when - all of a sudden - they came under an attack by several R-27/AA-10 missiles."

 

And according to the same article: "But, this was still considered as not enough, especially as the availability of Russian mercenaries now made it possible for Ethiopia to acquire more modern aircraft. Thus a deal valued approximately $150 million was agreed with Moscow for sale of eight surplus Su-27S’ (including two two-seat Su-27UBs).

 

'Supposedly, there should be no significant differences between early and new - or domestic and export - versions of R-27s, however, it seems, that this type so far has a worst combat record than even US Vietnam-era AIM-7Es or AIM-7Fs! This was certainly no good news for the Russians, which were keen to try out their new mounts and weapons under conditions of conventional warfare, and against a well organized enemy."

[Yellonet]

I am very sceptical about that claim, GGTharos. The missile seeker is tracking the reflected energy from the fighters RADAR. This is a steady, intensive beam (this is the whole point of STT). Chaff can momentarily break the steady return to the fighters radar, by having a big reflection - in ALL directions: the NOISE makes it impossible momentarily for the painting aircraft to gain the reflection. The whole idea is that this could cause a break in lock.

 

IF breaking the lock FAILS, my guess is the fighter RADAR continues to paint the real target with high energy, this being returned. It is this beam the SARH missile keeps following The SAHR missile at that point is not homing in on a mere NOISE source like the chaff cloud, which is reflecting the energy in all directions an thus has MUCH lower intensity.

 

You seem to imply on the other hand that chaff does not work on the NOISE principle, but on the return principle, i.e. that it produces a larger and better lockable echo, which is clearly different.

 

I still think that if you have lock, your SAHR missile will track the real target.

A SAR missile homes on the reflecting energy sent out by the radar, right? And as such it will most likely home on the strongest source as that should "drown" the weaker source, my theory works like this: If you're watching a big fire and then someone starts to shine a flashlight into your eyes from a short distance you probably wouldn't see the fire any more even though the fire is much larger and intense, but as the relative light level is much higher from the flashlight it would blind you and prevent you from seeing the fire.

 

So if the target starts deploying chaff the radars energy will be reflected by it and at some point when the missile gets close to the chaff the relative energy reflected by the chaff will be greater than the reflected energy from the target aircraft, thus the missile goes for the chaff without the "painter" ever losing lock.

 

Could it work like that?

Someone that knows this stuff get in here and explain! :)

[Whisper]

FAO D-Scythe : Thks for the correction :)

/me going to bed less idiot tonight

 

What are the typical illumination angles of SST mode in aircraft and ARH missile illuminator?

[D-Scythe]

A SAR missile homes on the reflecting energy sent out by the radar, right? And as such it will most likely home on the strongest source as that should "drown" the weaker source, just as if you're watching a candle light and then if someone starts to shine with a flashlight into your eyes you probably wouldn't see the candle light any more.

 

So if the target starts deploying chaff the radars energy will be reflected by it and at some point when the missile gets close to the chaff the relative energy reflected by the chaff will be greater than the reflected energy from the target aircraft, thus the missile goes for the chaff without the "painter" ever losing lock.

 

Could it work like that?

Someone that knows this stuff get in here and explain! :)

 

Here are some facts:

 

- modern monopulse radar missiles (AIM-7/120, R-77/27) can easily filter out chaff, because chaff is simply "noise" to them. In other words, chaff is like another form of ground clutter

- since chaff instantly slows down to zero airspeed, monopulse missiles have no problem filtering them out - it's like filtering out ground clutter

- chaff should only work on the beam, because that is when the target basically "blends" into the noise

- so, missiles don't actually lock onto chaff, it just loses the target in the noise presented by the chaff.

 

That's the basics.

[Yellonet]

So, beam and release chaff and you should have a pretty good chance of survival against AR and SAR missiles?

[D-Scythe]

FAO D-Scythe : Thks for the correction :)

/me going to bed less idiot tonight

 

What are the typical illumination angles of SST mode in aircraft and ARH missile illuminator?

 

Swingkid will knows a LOT more than I do, but the estimated FOV of the AIM-120 is about 10 degrees, although it can probably sharpen its angular resolution down to 1-4 degrees (estimated by Swingkid). For an SST aircraft, its typically much less, around 1.5 degrees I think.

 

The larger the radar antenna, the smaller the FOV.

 

So, beam and release chaff and you should have a pretty good chance of survival against AR and SAR missiles?

 

Unfortunately, nobody knows. However, pilots were trained to beam missiles since the 80s, and the AIM-120 was developed then too, so chances are it should have some measures in place to defeat the beaming+chaff, although this stuff is highly classified.

 

The only possible solution I see is if the AIM-120 is also provided with ranging information from its radar seeker in addition to its radar LOS guidance (which is basically what the missile has to do to complete a lead pursuit intercept). That way, the ground can be rejected on the basis that it is too far away (slant ranges are typically huge), and the chaff can be rejected on the basis that the resulting LOS correction would be too great.

 

However, Swingkid isn't a big fan of this idea. In any case, if ranging information is not used, there seems to be some data to support "special" trajectories that reduces the effectiveness of decoys, although nobody knows anything about them either. So now, with ranging and special trajectories out the window, we basically get uber chaff that should always work on the beam.

 

So now we're at a point where there are two separate ways to pursue this. One way is should modern radar missiles have their chaff rejection logic beefed up to reflect the possible existence of ways to defeat chaff? This might give more realistic BVR battles, but at the expense of realism, since we're guessing. The second way is just assume that if nothing is known about it, don't model it. This would be more realistic, but at the expense of stupid missiles.

[wsoul2k]

 

So if the target starts deploying chaff the radars energy will be reflected by it and at some point when the missile gets close to the chaff the relative energy reflected by the chaff will be greater than the reflected energy from the target aircraft, thus the missile goes for the chaff without the "painter" ever losing lock.

 

Could it work like that?

Someone that knows this stuff get in here and explain! :)

 

 

Yellonet

 

there is not such thing like "the missile goes for the chaff" in a SAR missile...the missile goes where the PAINTER tell it to go......if the painter can hold de lock...the missile will be ok it will just ignore the chaff

 

Is something like you are driving your car ....following a hot chick ( target ) in your front....and on your front a ugly girl ( chaff ) just pass trying to fool you...if you (PAINTER) dont turn your car (Missile) the car will continue to folow the hot chick...there is no way the car can choose for himself to folow the ugly girl :D

[D-Scythe]

Yellonet

 

there is not such thing like "the missile goes for the chaff" in a SAR missile...the missile goes where the PAINTER tell it to go......if the painter can hold de lock...the missile will be ok it will just ignore the chaff

 

Is something like you are driving your car ....following a hot chick ( target ) in your front....and on your front a ugly girl ( chaff ) just pass trying to fool you...if you (PAINTER) dont turn your car (Missile) the car will continue to folow the hot chick...there is no way the car can choose for himself to folow the ugly girl :D

 

You have absolutely no idea what you're talking about. Go back to the previous page and read my posts. As it is now, you're pretty clueless.

 

Again, to sum up how a SARH missile works, the illuminating radar is like a giant spotlight (imagine it covering the size of a football field) being shined on a robber in a forest. Thus, everything around the robber, including the trees and bushes, are also lit up.

 

The cop is like the SARH missile, and he has to find the robber on his own inside the forest. The spotlight does NOT tell the cop where exactly the robber is, but is simply a means for the cop to SEE the robber. Whether the cop can find the robber or not is entirely up to HIMSELF. He may see the robber for a few seconds, but the robber can still HIDE from him.

 

Got it?

 

In contrast, an ARH missile is like a cop with a powerful flashlight. Provided that the cop can keep his flashlight on the robber, he has a much better idea of where the robber is and thus, catching him. However, the robber can still jump behind a bush and hide from the cop.

[S77th-GOYA]

So chaff is like an acorn that grows really fast.

[GGTharos]

Easy, D-scythe ...

 

Nice analogy in a way though - except that compared to the cop, the missile will be pretty stupid in trying to find the robber again - the SARH missile is certainly dumber than the ARH one in this respect too, AFAIK.

 

Ship or ground-borne TVM/SARH however seem to be far nastier than either of those two.

[GGTharos]

So chaff is like an acorn that grows really fast.

 

Kinda?

 

Chaff is designed SPECIFICALLY to physically reflect the most radar energy possible. It is in fact an antenna geared to beam back the specific frequency you're painting it with, simply by virtue of the length it's cut to.

 

It could easily out-shine an aircraft's radar reflections ... but don't quote me on that until someoen does some math on it ;)

 

Essentially the RCS difference can be two to three orders of magnitude.

[tflash]

D-Scythe,

 

I think that is not entirely true.

 

1) OK the illuminating radar "paints" a larger space than the target, so that if the target drops chaff, this chaff gets also illuminated ... for a while

 

2) you seem to overestimate the painted area in STT. Of course, at distance the radar will see two nearby aircraft as 1 for the same reason, but as they near, the radar is perfectly capable of discerning very closeby flying aircraft and directing the radar energy on one of them.

 

3) so, iff chaff is released under the right angle towards the beamer, for a VERY short time it will be illuminated by the STT beam and yield a high noise level effecively blinding the radar

 

4) moments afterwards, the distance between chaff and fighter will be enough for the fighter radar to reject the chaff

 

5) In my view, in NO WAY a SAHR missile is LOOKING after a target in a bunch of illuminated objects. This is plain wrong. How would it know what to look for. It is just following the reflected radar beam. essentially, in a head-on fight, there are no trees, there is no forest.

 

6) Normally, only the target gives sufficient reflection. This can be temporarily spoiled by a chaf release: the beam reflection by the target is concealed by the big return from the chaff cloud

 

7) if the TARGET is still in the FOV of the missile when the chaff has died away, the missile will just follow course.

 

The forets story is more likely in a look-down sceanrio. There, yyou need Doppler for the FIGHTERS radar to be able to discriminate the target and keep lock, NOT for the missile to search for the target in some illuminated forest!

 

I think you are making SAHR missiles way to intelligent.

[wsoul2k]

You have absolutely no idea what you're talking about. Go back to the previous page and read my posts. As it is now, you're pretty clueless.

 

I already read your posts D :)

 

 

Again, to sum up how a SARH missile works, the illuminating radar is like a giant spotlight (imagine it covering the size of a football field) being shined on a robber in a forest. Thus, everything around the robber, including the trees and bushes, are also lit up.

 

The cop is like the SARH missile, and he has to find the robber on his own inside the forest. The spotlight does NOT tell the cop where exactly the robber is, but is simply a means for the cop to SEE the robber.

 

But D in this situation if i have 2 robbers i realy dont know how the coop will know witch one he have to get....

 

If this work this way if i fire an R-27 in 2 closest planes there is no way i can guarantee the missile will hit the Locked target ..because in your words it have to find it for him self...

 

 

IMHO the chaff is a real big target.....just one more big target but if the iluminating radar can HOLD the lock i really cant see a way to the missiles choose other...

 

Im really confuse rigth now

 

Sorry for the poor english if you have time add me on msn to chat about ok i will really apreciate wsoul1974@hotmail.com

[GGTharos]

Wsoul, the answer is simple: The cop would go after the fatter robber ;)

[Yellonet]

D-Scythe,

 

I think that is not entirely true.

 

1) OK the illuminating radar "paints" a larger space than the target, so that if the target drops chaff, this chaff gets also illuminated ... for a while

 

2) you seem to overestimate the painted area in STT. Of course, at distance the radar will see two nearby aircraft as 1 for the same reason, but as they near, the radar is perfectly capable of discerning very closeby flying aircraft and directing the radar energy on one of them.

 

3) so, iff chaff is released under the right angle towards the beamer, for a VERY short time it will be illuminated by the STT beam and yield a high noise level effecively blinding the radar

 

4) moments afterwards, the distance between chaff and fighter will be enough for the fighter radar to reject the chaff

 

5) In my view, in NO WAY a SAHR missile is LOOKING after a target in a bunch of illuminated objects. This is plain wrong. How would it know what to look for. It is just following the reflected radar beam. essentially, in a head-on fight, there are no trees, there is no forest.

 

6) Normally, only the target gives sufficient reflection. This can be temporarily spoiled by a chaf release: the beam reflection by the target is concealed by the big return from the chaff cloud

 

7) if the TARGET is still in the FOV of the missile when the chaff has died away, the missile will just follow course.

 

The forets story is more likely in a look-down sceanrio. There, yyou need Doppler for the FIGHTERS radar to be able to discriminate the target and keep lock, NOT for the missile to search for the target in some illuminated forest!

 

I think you are making SAHR missiles way to intelligent.

When a non-manuevering target is releasing chaff the missile will probably not have a hard time getting to the target, however when the target is manuevering and releasing chaff the missile will go towards the chaff for a small amount of time and while it is doing that the target will have got out of the way of the missile and it will have to use up a lot of energy to get back on the targets track.

[GGTharos]

D-Scythe,

 

I think that is not entirely true.

 

1) OK the illuminating radar "paints" a larger space than the target, so that if the target drops chaff, this chaff gets also illuminated ... for a while

 

Quite a while actually - the beam is defined as the volume within which the power is greater than half of the emitted power. However chaff is an extremely strong reflector and can remain quite bright even in the sidelobes.

 

2) you seem to overestimate the painted area in STT. Of course, at distance the radar will see two nearby aircraft as 1 for the same reason, but as they near, the radar is perfectly capable of discerning very closeby flying aircraft and directing the radar energy on one of them.

 

1 degree at 1km is 17m. 10nm is about 18km. you do the math, and don't forget those sidelobes ;)

 

3) so, iff chaff is released under the right angle towards the beamer, for a VERY short time it will be illuminated by the STT beam and yield a high noise level effecively blinding the radar

 

Maybe. It might not blind the radar (but the missile is another story)

 

4) moments afterwards, the distance between chaff and fighter will be enough for the fighter radar to reject the chaff

 

Yes, more than likely - except that the target is beaming and you don't see it either.

 

5) In my view, in NO WAY a SAHR missile is LOOKING after a target in a bunch of illuminated objects. This is plain wrong. How would it know what to look for. It is just following the reflected radar beam. essentially, in a head-on fight, there are no trees, there is no forest.

 

Yes, it is THE MISSILE that is looking. It's looking for the STRONGEST reflection coming from that beam, NOT where the beam is centered! That's merely COINCIDENCE. The missile computes it's own target center!

It also use pulse-doppler to discriminate chaff from target.

 

6) Normally, only the target gives sufficient reflection. This can be temporarily spoiled by a chaf release: the beam reflection by the target is concealed by the big return from the chaff cloud

 

Semi-correct.

 

7) if the TARGET is still in the FOV of the missile when the chaff has died away, the missile will just follow course.

 

Most likely correct but not in all situations. (Chaff doesn't die that quick)

 

The forets story is more likely in a look-down sceanrio. There, yyou need Doppler for the FIGHTERS radar to be able to discriminate the target and keep lock, NOT for the missile to search for the target in some illuminated forest!

 

Untrue. Looking at chaff is no different than looking at the ground, conceptually. They're both clutter.

The fighter radar can do whatever it wants. It is THE MISSILE which must choose the reflection to home in on. PERIOD! The ONLY thing the fighter radar does is provide illumination.

As suck, the missile must search for and discriminate the target on its own.

 

Defeating the FIGHTER radar and the MISSILE seeker are two DIFFERENT things.

 

I think you are making SAHR missiles way to intelligent.

 

They're not too dumb either.

[TucksonSonny]

Not since active radar homers. Nothing matches the record of the AMRAAM currently, and it is the only active radar homer currently used in combat.

 

That was one hell of a costly spam record supported by AWACS :icon_kidr

[GGTharos]

That was one hell of a costly spam record supported by AWACS :icon_kidr

 

No, the spam records are held by Sa-2's and AGM-88's.

 

AIM-120's had no spamming issues.

 

And I'm not sure where the 'supported by AWACS' thing comes in at all. Th point is that individual aircraft were unable to dodge individual missiles fired at them.

[D-Scythe]

Guys, believe GG and I on this one okay? In an SARH missile, the missile tells itself where to go - even if the illuminating radar wants to tell the missile what to do, it can't. The datalink in the missile is not equipped for that.

 

But D in this situation if i have 2 robbers i realy dont know how the coop will know witch one he have to get....

 

Simple answer. Take the cop and two robbers. If the cop is chasing one robber, and then another robber runs right by in the opposite direction, the cop will continue to chase the first robber because it would take too much energy for the cop to stop, change direction and go after the new robber. Cops are lazy.

 

If both robbers are heading in exactly the same speed and direction, the cop will go after the fattest robber.

 

you seem to overestimate the painted area in STT. Of course, at distance the radar will see two nearby aircraft as 1 for the same reason, but as they near, the radar is perfectly capable of discerning very closeby flying aircraft and directing the radar energy on one of them.

 

Do the math yourself. With a 1.5 degree FOV, the illuminating radar will be painting an area of airspace 13 490 m^2 around the target at only 5 km, which is only 2.7 miles. At 20 km, or 11 miles (just inside BVR range), the area painted by the illuminating radar around the target is 21 780 492.8 m^2 around the target.

 

moments afterwards, the distance between chaff and fighter will be enough for the fighter radar to reject the chaff

 

Unfortunately, it doesn't work that way. It doesn't matter if the fighter radar can reject the chaff - it matters if the MISSILE radar, whether SARH or ARH, can reject the chaff. The fighter radar simply "lights up" the general area of the target so that the missile can see it.

 

In my view, in NO WAY a SAHR missile is LOOKING after a target in a bunch of illuminated objects. This is plain wrong. How would it know what to look for. It is just following the reflected radar beam. essentially, in a head-on fight, there are no trees, there is no forest.

 

Again, in a head on fight, the chaff "looks" different than the target.Thus, the missile would easily know what to look for. Chaff is like ground clutter, and is rejected by the missile in exactly the same way.

 

How a target "looks" to a missile is dependent on its closure rate relative to the missile.

 

However, if the target is beaming, then the target "blends" into the clutter, because the closure of the ground (and chaff) is the same as the closure to the target. Thus, how will the missile pick out the target from the ground and chaff?

 

It would be like having 200/200 vision and trying to pick out a small piece of clear tape (the target) from a wall (chaff) on the other side of the room. It simply can't be done. The fighter radar, on the other hand, might have 20/20 vision, so it would shine a flashlight at the wall where the target is. But the guy with 200/200 vision (the missile) will still not see it.

 

On the other hand, let's say the target was not on the beam, so like head on or tail on. That would like that same piece of clear tape moving in random direction over the wall. Since your eye can track movement extremely well, it shouldn't be too difficult to pick out the piece of tape (target) from the wall (chaff). But if the tape stops moving, it disappears.

 

That's exactly what happens in the beam.

[S77th-GOYA]

So who planted the other trees?

[D-Scythe]

So who planted the other trees?

 

The ground.

 

If it is a look up situation, the cop and robber won't be in a forest, but more like a meadow or patch of grass. Yet, the robber will still be able to throw out chaff, which is like a bag of seeds, thus instantly growing a mini-forest for himself to hide in.

 

For a better understanding of beaming though, use the piece of tape analogy. It's better suited for it.