Chaff and R27(E)R

[pepin1234]

when we get into 25km range the Chaff should not affect the missile.

[rami80]

when we get into 25km range the Chaff should not affect the missile.

 

Can you explain why please?

[TheFurNinja]

So I want to check with you guys that im thinking correctly.

 

So chaff is reflective, and therefore unless being illuminated by a radar that it is nothing but floating aluminum.

 

The Su-27 uses its radar and for the first part of a R-27s flight it is in datalink and later switches to SARH when datalink cannot be held for any more range, right?

 

So from that: As long as the Su-27 can properly track the target through the chaff and the missile shouldn't be confused unless its beyond datalink range.

 

So theoretically with a hybrid style lock with both EO and Radar (because they are integrated and slaved together), you should be able to track a target through any amount of chaff (given a solid heat signature from the target). Making it extremely hard for any enemy aircraft to shake the missile until it was far enough from the launch platform for SARH.

 

From what I read and remember this is the secret to the Su-27s BVR capabilities. I wanted to verify with some of you more experienced members who may have gotten into more detail than me about this aircraft.

 

Is this correct? And if so is it modeled in game?

 

Because from what I know, as long as I can maintain a lock the missile should follow my target regardless of chaff unless it was using its terminal SARH guidance.

Edited December 9, 2015 by TheFurNinja

[blkspade]

All that I've ever heard about the SARH missiles depicted in game, all rely on radar for terminal guidance. Also the chaff in game is apparently invisible to the platform radar, when it should actually be affecting it. So seeing missiles mistrack due to chaff by itself may be a misrepresentation of what is really going on. As in we don't perceive any degradation of lock stability on our MFD even though its happening.

[*Rage*]

In essense youre right FurNinja. Right now the (E)R will misstrack off the rail to the first chaff in its FOV. Its a complete nonsence. Mostly for the reasons you posted.

[GGTharos]

The Su-27 uses its radar and for the first part of a R-27s flight it is in datalink and later switches to SARH when datalink cannot be held for any more range, right?

 

From what was explained to us, once the missile seeker acquires, it ignores the DL - that's for the R-27, don't apply it liberally to other missiles.

 

So from that: As long as the Su-27 can properly track the target through the chaff the missile shouldn't be confused unless its beyond datalink range.

There's no such thing as 'beyond datalink range'.

 

So theoretically with a hybrid style lock with both EO and Radar (because they are integrated and slaved together), you should be able to track a target through any amount of chaff (given a solid heat signature from the target). Making it extremely hard for any enemy aircraft to shake the missile until it was far enough from the launch platform for SARH.

 

That is patently incorrect. Chaff is not necessarily a separate, discrete target - it may move the centroid well aft of the aircraft so the missile will miss anyway. But yes, having the DL COULD help when combined with a smart enough missile.

Also, the missile is ignoring the DL at this point.

 

Is this correct? And if so is it modeled in game?

What is modeled in the game is, if the missile sees chaff, it rolls a die to see if it will track the chaff instead of the intended target.

 

Because from what I know, as long as I can maintain a lock the missile should follow my target regardless of chaff unless it was using its terminal SARH guidance.

Q: When would it not be using terminal guidance?

A: When it's too far for its little seeker to pick up the reflection from the target.

Edited December 9, 2015 by GGTharos

[Exorcet]

So I want to check with you guys that im thinking correctly.

 

So chaff is reflective, and therefore unless being illuminated by a radar that it is nothing but floating aluminum.

 

The Su-27 uses its radar and for the first part of a R-27s flight it is in datalink and later switches to SARH when datalink cannot be held for any more range, right?

 

So from that: As long as the Su-27 can properly track the target through the chaff the missile shouldn't be confused unless its beyond datalink range.

 

So theoretically with a hybrid style lock with both EO and Radar (because they are integrated and slaved together), you should be able to track a target through any amount of chaff (given a solid heat signature from the target). Making it extremely hard for any enemy aircraft to shake the missile until it was far enough from the launch platform for SARH.

 

From what I read and remember this is the secret to the Su-27s BVR capabilities. I wanted to verify with some of you more experienced members who may have gotten into more detail than me about this aircraft.

 

Is this correct? And if so is it modeled in game?

 

Because from what I know, as long as I can maintain a lock the missile should follow my target regardless of chaff unless it was using its terminal SARH guidance.

 

 

GG covered this and knows more on this subject than I do, but I want to reply anyway. Don't think of the radar as being able to "see" targets. It gets a return signal and needs to decide what to chase. While chaff is obviously not an aircraft visually, it's not necessarily easy to tell the two apart with radar.

 

Consider the case of an aircraft splitting in half in flight. One half goes left, one goes right. If radar was tracking this plane, what happens at that point? One blob just became two blobs and there is no real reason to pick one over the other. This could still happen even with multiple sensors working together, one case where the IR won't help is a direct tail on aspect chase as the chaff, plane, and IR signature are all going to be in line.

[pr1malr8ge]

A plane flying at 900km/h (M0.7) moves 250 metres away from the chaff it releases every second

 

I'm not trying to start an argument with you rage. I just want to point out one flaw with this equation.

 

your math is based on the chaff being "stationary" which would mean upon release it would need to be ejected at 900km/h.

In reality the chaff will be ejected with maybe a 100khm rate or less. Thus for a short period of time it will be moving 800km/h behind and spreading in size and slowing down.

 

[*Rage*]

I'm not trying to start an argument with you rage. I just want to point out one flaw with this equation.

 

your math is based on the chaff being "stationary" which would mean upon release it would need to be ejected at 900km/h.

In reality the chaff will be ejected with maybe a 100khm rate or less. Thus for a short period of time it will be moving 800km/h behind and spreading in size and slowing down.

 

Relative to the target the chaff decelerates MASSIVELY very quickly. The current trend for ERs to guide to chaff miles behind the target while its still recieving updates from the host radar is ridiculous.

 

Same in many other situations where spamming chaff works wonders.

Edited December 9, 2015 by ///Rage

[*Rage*]

Edit: Double post.

[Alfa]

So I want to check with you guys that im thinking correctly.

 

So chaff is reflective, and therefore unless being illuminated by a radar that it is nothing but floating aluminum.

 

The Su-27 uses its radar and for the first part of a R-27s flight it is in datalink and later switches to SARH when datalink cannot be held for any more range, right?

 

For the initial stage of flight, the missile is steered to the target by its onboard inertial navigation system based on a target fix uploaded to it prior to launch and updates transmitted to it via datalink from the aircraft radar after launch - it switches to SARH when the target comes within range of the missile seeker.

 

So theoretically with a hybrid style lock with both EO and Radar (because they are integrated and slaved together), you should be able to track a target through any amount of chaff (given a solid heat signature from the target). Making it extremely hard for any enemy aircraft to shake the missile until it was far enough from the launch platform for SARH.

 

Well close enough to target for SARH :) .

 

Because from what I know, as long as I can maintain a lock the missile should follow my target regardless of chaff unless it was using its terminal SARH guidance.

 

Correct.

[Alfa]

Don't think of the radar as being able to "see" targets. It gets a return signal and needs to decide what to chase. While chaff is obviously not an aircraft visually, it's not necessarily easy to tell the two apart with radar.

 

Don't think of the radar as being able to "see" a target - when tracking in STT it scans a small area around the target - pings the target, gets a return then pings it again and get a new return. Chaff may momentarily present an alternative return, but it does not behave like an aircraft.

[Alfa]

There's no such thing as 'beyond datalink range'.

 

Eh what? :)

 

That is patently incorrect. Chaff is not necessarily a separate, discrete target - it may move the centroid well aft of the aircraft so the missile will miss anyway. But yes, having the DL COULD help when combined with a smart enough missile.

Also, the missile is ignoring the DL at this point.

 

He was talking about the missile not being affected by chaff while under midcourse guidance.

[pr1malr8ge]

Relative to the target the chaff decelerates MASSIVELY very quickly. The current trend for ERs to guide to chaff miles behind the target while its still recieving updates from the host radar is ridiculous.

 

Same in many other situations where spamming chaff works wonders.

 

Yes you're right about the speed change, I was just merely stating your speeds were based on stationary chaff clouds.

 

While I see your complaint [same things with the aim7 gobbling chaff clouds]

There is a point where it is just not feasible to simulate chaff due to complexity of programming, entities in the server, and available computing power.

 

Eh what? :)

 

 

 

He was talking about the missile not being affected by chaff while under midcourse guidance.

 

Tharos was referring to someone elses post about being beyond DL's range. which the missile will be out of potential energy before that happens.

 

Also DL in missiles [and correct me if I'm wrong] is a "oneway" receive communication. The missile DOES not respond back with I'm here etc etc.

The data link is meant for wide angle corrections and does not guide the missile to the impact zone. It only feeds it with generalized direction changes of the target and the seeker is does the rest via a beam guide. So if there is enough "reflected" energy from the chaff cloud that the seeker only sees that it will guide to that regardless of datalink.

 

While I could be wrong about the above, I don't think missiles are installed with any type of actual inertial/gps systems for it to determine where it is in space due to cost, size and complexity restraints. so with that if launched it only has it's original position and its calculated position in space. This does not mean it is actually at where it thinks it is. a few inches off where it thinks it is when a Data link course update is computed could result in a 1000+ft at it's intended intercept point.

[GGTharos]

Eh what? :)

 

Know of any missiles that out-range their datalinks? :)

 

He was talking about the missile not being affected by chaff while under midcourse guidance.

 

I might have been filling in information.

[Exorcet]

Don't think of the radar as being able to "see" a target - when tracking in STT it scans a small area around the target - pings the target, gets a return then pings it again and get a new return. Chaff may momentarily present an alternative return, but it does not behave like an aircraft.

 

Wouldn't the length of time that chaff stays in the window depend on the trajectory of the aircraft and the chaff itself? I'd assume that if you lined things up properly, it gets difficult to tell which is which. And if you keep ejecting chaff, that momentary interference remains even longer. Each time, the radar needs to pick between aircraft and chaff, right?

 

I know I didn't mention any kind of filtering in my example, so it would apply to something less complex than a fighter radar, but as far as I know (not even an amateur) picking the two apart is still something that a modern radar can fail at.

[GGTharos]

Chaff can present a strong return for a pretty long time (within the relative flight time of the missile); as you get closer it may leave the FoV quickly, but a steady release program can cause it to shift the target centroid enough to cause a 'safe miss distance'. This type of thing is not represented in the game (nor are a lot of other things, of course).

 

All the literature indicates that chaff is typically used with maneuver, and I believe we had someone post an excellent video here of chaff breaking a hornet's gun tracking solution ... you don't really get much closer than that, and that radar set has pretty capable ECCM.

 

A missile changes things (for one, it's approaching much faster and is on a collision course); if it's smart enough, it will try to build and maintain a track of the target's movement and filter out anything that forces a rapid shift ... but what if the fighter maneuvers at the same time and makes itself look like the chaff, kinetically?

 

My point isn't that chaff can't be rejected - it can be. My point is that there isn't much out there that flat out ignores chaff.

 

Anyway, it's just a simple example and simplified scenario.

 

Don't think of the radar as being able to "see" a target - when tracking in STT it scans a small area around the target - pings the target, gets a return then pings it again and get a new return. Chaff may momentarily present an alternative return, but it does not behave like an aircraft.

[TheFurNinja]

Chaff can present a strong return for a pretty long time (within the relative flight time of the missile); as you get closer it may leave the FoV quickly, but a steady release program can cause it to shift the target centroid enough to cause a 'safe miss distance'. This type of thing is not represented in the game (nor are a lot of other things, of course).

 

All the literature indicates that chaff is typically used with maneuver, and I believe we had someone post an excellent video here of chaff breaking a hornet's gun tracking solution ... you don't really get much closer than that, and that radar set has pretty capable ECCM.

 

A missile changes things (for one, it's approaching much faster and is on a collision course); if it's smart enough, it will try to build and maintain a track of the target's movement and filter out anything that forces a rapid shift ... but what if the fighter maneuvers at the same time and makes itself look like the chaff, kinetically?

 

My point isn't that chaff can't be rejected - it can be. My point is that there isn't much out there that flat out ignores chaff.

 

Anyway, it's just a simple example and simplified scenario.

I would like to clear up what I meant by "see" would be a gross generalization for interpret. A radar interprets incoming data and calls it a target, the missile interprets incoming data from the radar and calculates a path, etc...

 

But that clears up some of my questions.

 

So just to verify, chaff confuses the host radar in-game? Because to me that is the biggest issue. I would feel more comfortable with missile behavior if things like that were modeled correctly.

 

For me it (the R-27R and ER) just seems like right off the rail my missiles go for the first chaff but this shouldn't be the case until it switches over to SARH guidance from what I can tell.

 

Now with a one-way data-link I can definitely see the issues around that and what I said about the integration of the EO sensors as a work-around to guide the missile. It would simply not work due to limitations.

 

This still doesn't change the fact that it seems like these missiles are just going haywire midcourse just seconds off the rail.

 

Is there a good place to get information for this? I wish I could know more :(

 

Thanks for your answers guys. All I want is the truth and the best simulation for all of us.

[GGTharos]

So just to verify, chaff confuses the host radar in-game? Because to me that is the biggest issue. I would feel more comfortable with missile behavior if things like that were modeled correctly.

 

No it does not, and it also doesn't really matter: In the end whether the missile goes for the chaff or not is probabilistic. It could be made more realistic, yes, and I'd love that, but the probabilistic approach is adequate.

 

For me it (the R-27R and ER) just seems like right off the rail my missiles go for the first chaff but this shouldn't be the case until it switches over to SARH guidance from what I can tell.

How do you know it hasn't? :) But in any case, fair enough, not everything is working quite right. At fairly long ranges chaff and target may even share the same radar cell for a while which causes its own problems (or lack thereof!)

 

Now with a one-way data-link I can definitely see the issues around that and what I said about the integration of the EO sensors as a work-around to guide the missile. It would simply not work due to limitations.

The data-link has nothing to do with it in this case. You COULD use it, but there's probably a reason why these missiles use terminal homing instead of some sort of host-based steering-to-target. You could generate a datalink signal from the EOS. In situations where you're steering the radar with EOS, you're basically already in some sort of failure mode - sort of like FLOOD for the F-15.

 

This still doesn't change the fact that it seems like these missiles are just going haywire midcourse just seconds off the rail.

 

Is there a good place to get information for this? I wish I could know more :(

 

Thanks for your answers guys. All I want is the truth and the best simulation for all of us.

The truth is out there ... locked in vaults where we can't have it :)

In all seriousness, yes, there are a lot of sources out there, they are most often either difficult to find, not free, or both. Learning about this stuff is a long and difficult process; there is a lot of knowledge you can gain from things like the radar bible though.

 

Be prepared to do math and realize that general academic information isn't always directly applicable to real weapons: There can be reasons of any sort that will cause something to work differently than you expect.

[*Rage*]

No it does not, and it also doesn't really matter: In the end whether the missile goes for the chaff or not is probabilistic. It could be made more realistic, yes, and I'd love that, but the probabilistic approach is adequate.

 

The current situation is most definitely not adequate. Seeing a missile trail make a massive diversion way from you at 30 clicks. Its ridiculous.

 

Basically what youre saying is the same as like saying, well hey, since the Pk of a missile is x then as long as the in game pk is also x then thats ok, regardless of how that pk is achieved. Missile flying backward or to the moon it doesnt matter as long as the pk when I quit the game is the same as real life. Actually no. How the mechanics are represented is just as important as the end result (and im of the opinion the current end result is wrong as well). The mechanics dictate the style of play and the realism of the simulation we're flying.

[pepin1234]

Can you explain why please?

 

The R-27 Should not be affected by Chaff into 25km. Why? because the Mig/Su onboard radar and the R-27 seeker head have been made with improvement against chaffs countermeasures. Into the 25km the Chaffs effect is downgraded by the closer distance from onboard radar/seeker head to target. Closer distance, less chaff effect

 

The same with the Flares. We see in DCS how the IR seeker head fallow the flares easily. when we talk about air combat with a launch tail on, the missile system have better performance and in DCS with only one flare the missile go hell.

 

both issues commented before are damaging the RU figthers, because they use most this technology.

 

Also we get a minus performance when we see the RWR in DCS with a warning missile launch just when the SARH missile get out of the station. This behavior is INCORRECT, the SARH seeker head is active in a later flight stage, not so early. So is no reason the enemy get aware with missile on his way, warning so early.

[GGTharos]

I didn't say the mechanics weren't important, in fact I said that not everything is working correctly.

 

But yes, I did say that the stochastic approach is adequate. That's all it is.

[pepin1234]

I did say that the stochastic approach is adequate. That's all it is.

 

The stochastic should be adequate, right now is not, right now is biased.

[Sweep]

Sweep's take on the ER thread

 

Oh god, this thread is still going strong...as someone who looks for better tactics in-game and enjoys fun stuff, here is what you should do with your ERs:

 

Step one) Take a Su-33 and load it with 8 ERs

Step two) Fly to enemy airfield

Step three) Enable launch override

Step four) Aim at enemy parking area(s) and...

Step five) Call your Fox 1s

Step six) Laugh

 

As the guidance for ERs and SARH in general is somewhat screwy, using such weapons in an unguided state yields the highest Kill Probability and fighter trade ratio. :thumbup:

[GGTharos]

It isn't biased, it's not functioning like you'd like it to. LOL with your accusations of bias.

 

The stochastic should be adequate, right now is not, right now is biased.