reported AIM-120C losing targets easily for chaff even at close ranges

[dundun92]

4 hours ago, nighthawk2174 said:

Right now it seems that once notched/chaffed the missile is incapable of re-acquiring the target which it should be able to do.

IMO thats actually the biggest problem with the current ccm implementation. Yes, its annoying that the AMRAAM goes for chaff too much. But whats the most annoying is when a target makes a 9+ G turn through the notch at like M1, and because they happened to drop 1 chaff the 0.1 seconds they were in the notch the missile is spoofed and will never reacquire.

Or the guy that notched for a half-second, spams chaff and immediately recommits. Yes, im not doubting the chaff may fool it for a second or two, and do other unfavorable things. But this is way beyond that. Chaff dropped from the notch basically permanently trashes the missile like some EMP/DIRCM. That IMO is the biggest problem.

 

I should also probably add, this isnt really an AMRAAM only thing. This is how all radar MRMs behave in game. If you drop chaff 0.1 m/s outside the notch the missile can/will reacquire if you recommit, or keep turning to cold aspect. But the instant you get in the notch filter, the chaff just behaves much differently, and its honestly quite gamey and unrealistic. Its quite ironic that because of this ECM increases the PK of DCS radar missiles vs beaming and chaffing, as ECM removes the notch filter as a factor.

Edited April 5, 2021 by dundun92

[Csgo GE oh yeah]

[quote=dundun92]Or maybe you just dont know employ them properly?[/quote]

Yes Dundun92 that's probably it. 

 

Edited April 5, 2021 by Csgo GE oh yeah

[some1]

 

I don't know if the current problem is exacerbated by AI being able to pull a perfect notch every time and dump chaff at the right moment, but the current missile behaviour sure does not look correct. I tried several basic head-on engagements launching missiles from about 10 nm, and every time at least one missile decided it's better to stop the lead pursuit and do a 25g turn against a chaff that was 30 degrees off-boresight. 

 

Same problem also with SD-10. 

 

Sample tracks attached.

 

 

18.trk Tacview-20210406-181850-DCS-tst_F16new.zip.acmi 16.trk Tacview-20210406-182404-DCS-tst_FA18new.zip.acmi

[SgtPappy]

51 minutes ago, some1 said:

 

I don't know if the current problem is exacerbated by AI being able to pull a perfect notch every time and dump chaff at the right moment, but the current missile behaviour sure does not look correct. I tried several basic head-on engagements launching missiles from about 10 nm, and every time at least one missile decided it's better to stop the lead pursuit and do a 25g turn against a chaff that was 30 degrees off-boresight. 

 

Same problem also with SD-10. 

 

Sample tracks attached.

 

 

 

Yea, the AI has special a capability to spoof missiles far more easily, I guess since they are AI and can't fight like we do.

 

But yes, missiles being affected by chaff far outside the resolution cell and also pulling crazy G's toward said chaff have always been a thing in DCS. Also, I could have sworn the AIM-120 used to pick targets up again if they immediately recommitted but I can't be sure since I'm usually on 1960s-80s servers. For sure, there was a time when the AIM-54's could pick you back up again but I haven't tested if that capability has returned.

[nighthawk2174]

3 hours ago, some1 said:

 

I don't know if the current problem is exacerbated by AI being able to pull a perfect notch every time and dump chaff at the right moment, but the current missile behaviour sure does not look correct. I tried several basic head-on engagements launching missiles from about 10 nm, and every time at least one missile decided it's better to stop the lead pursuit and do a 25g turn against a chaff that was 30 degrees off-boresight. 

 

Same problem also with SD-10. 

 

Sample tracks attached.

 

 

18.trk 1.43 MB · 0 downloads Tacview-20210406-181850-DCS-tst_F16new.zip.acmi 223.36 kB · 0 downloads 16.trk 1.78 MB · 0 downloads Tacview-20210406-182404-DCS-tst_FA18new.zip.acmi 205.94 kB · 0 downloads

These are some of the clearer clips of this issue thanks for posting them, but yeah its a big annoyance watching them thinking that your about to get the kill then they just pull max G off to the side.

[Noctrach]

...and just reducing the chaff lifetime value to <1s instead of 8+ would mitigate 95% of these issues and make everything behave much more believably at nearly zero developer time invested. But I guess thats too pragmatic a solution...

Edited April 7, 2021 by Noctrach

[Karon]

42 minutes ago, Noctrach said:

...and just reducing the chaff lifetime value to <1s instead of 8+ would mitigate 95% of these issues and make everything behave much more believably at nearly zero developer time invested. But I guess thats too pragmatic a solution...

 

I'd be happier with an exponential decrease of the "chaff factor" and a lifetime slightly longer, mate.
Just to give you an idea with random numbers, let's say lifetime= 3". Then:
T0 → 1.0
T1 → 0.8
T2 → 0.4
T3 → 0.0

 

Of course this is for gaming purpose, it's not a realistic approach.

[Arikaj]

13 hours ago, SgtPappy said:

But yes, missiles being affected by chaff far outside the resolution cell and also pulling crazy G's toward said chaff have always been a thing in DCS

I disagree. We never had this problem. I just had a year of pause in DCS and when I came back 2 or 3 months ago I was suprised they started to behave like this. It is just a recent behaviour. 

[Noctrach]

2 hours ago, Karon said:

I'd be happier with an exponential decrease of the "chaff factor" and a lifetime slightly longer, mate.
Just to give you an idea with random numbers, let's say lifetime= 3". Then:
T0 → 1.0
T1 → 0.8
T2 → 0.4
T3 → 0.0

 

Of course this is for gaming purpose, it's not a realistic approach.

For a longer term solution there's a lot of things that they can improve with chaff to simulate it blooming, dropping below doppler gates and out of beam limits. There's the pull-off interaction with aircraft radars to consider, interaction with pulse vs pulse-doppler, interaction with ECM, etc.

 

For the short term, reducing the lifetime to a single second would be a decent mimicry of chaff's interaction with PD radars, while literally only requiring a Lua value change.

It would solve all the current issues at minimal effort and then they can revisit the entire ECM aspect of the sim for a thorough rework in Two Weeks™

 

Maybe something to consider @BIGNEWY

[BIGNEWY]

The team are working on a permanent solution, it may not make it in the first 2.7, it is high priority, but also challenging one to get right. 

 

thanks

[Karon]

3 minutes ago, Noctrach said:

For a longer term solution there's a lot of things that they can improve with chaff to simulate it blooming, dropping below doppler gates and out of beam limits. There's the pull-off interaction with aircraft radars to consider, interaction with pulse vs pulse-doppler, interaction with ECM, etc.

 

For the short term, reducing the lifetime to a single second would be a decent mimicry of chaff's interaction with PD radars, while literally only requiring a Lua value change.

It would solve all the current issues at minimal effort and then they can revisit the entire ECM aspect of the sim for a thorough rework in Two Weeks™

 

Maybe something to consider @BIGNEWY

Yeah I agree, but that solution would change the interaction with CW / P radars a bit too much. Don't get me wrong, I'll take whatever comes!

 

EDIT: sniped by Mr BIG. Great news Sir, thanks for the update

Edited April 7, 2021 by Karon

[SgtPappy]

9 hours ago, Arikaj said:

I disagree. We never had this problem. I just had a year of pause in DCS and when I came back 2 or 3 months ago I was suprised they started to behave like this. It is just a recent behaviour. 

 

I'm talking specifically about missiles pulling G's toward chaff far away from the res cell while the target is correctly beaming/notching. I'm fairly sure I've read multiple threads of this but maybe my memory is fuzzy in terms of when. 

 

As for the issue of this thread itself (missiles spoofed by close range hot or cold target with blinking jammer + chaff), that is certainly new. 

Edited April 7, 2021 by SgtPappy

[MARLAN_]

Elapsed Time: +00:59:47

 

AIM-120C launched HOT aspect, 6.4nm, gets spoofed by the FIRST chaff bundle, while skylined, bandit remains HOT and 120C remains spoofed.

 

You can see in the Tacview by going to HUD view selecting the AIM-120C that it locks onto the very first chaff bundle.

 

TACVIEW: https://drive.google.com/file/d/1xKx_A9awr6-N-mgvVKgizWUwXjiuJk2y/view?usp=drivesdk

TRACK FILE: https://drive.google.com/file/d/1m3jqrSY1tcLSanUonVKr7Y4n-ZIqhe1j/view?usp=drivesdk

 

EDIT: It happens a second time at +1:20:55, bandit is COLD aspect, skylined, and it bites off on a chaff. He does start a very small vertical notch, but not nearly enough to actually be notched, and he is skylined while cold....

[GGTharos]

No one's going to watch a one hour track file.  Recreate in a simple, short mission.

[Max1mus]

Be careful what you wish for. When ED last made AMRAAMs nearly unchaffable, they added a different mechanic that allowed people to just barrel roll it head on with ECM on. It is more effective now. Something worth adding is that AIM-120C, despite uninformed complaints here, is the missile in DCS with the by far best tracking and countermeasure resistance. Within the no-run-zone, no other missile more likely to take down the target than AIM-120C.

 

To add to the whole "uninformed" point. As usual with these rage threats, most posters dont understand the changes ED makes and how that changes the effect of missiles on the fight, perhabs with the exception of posters like Noctrach, who fly in groups that spend a lot of time testing said missiles.

 

In the latest changelog, a thing called "low altitude tracking errors" was introduced. This allows specificly the AIM-7 and AIM-120 to be defeated in different ways compared to the previous patch. The R-27 was affected by this for a long time, but arguably to a lesser extent.

 

Of course im not surprised that this wasnt mentioned in here. Same as that whole ECM dodging thing. It does not seem like most of the posters in here have spent a lot of time doing Air to Air in DCS. ED surely understands that with how many new players have entered DCS recently, the forums and platforms like hoggit will be filled with this sort of stuff. Its not any different in other sims or games.

[dundun92]

1 hour ago, Max1mus said:

The R-27 was affected by this for a long time

it wasnt technically, although the practical effect wasnt much different. It had the hardcoded minimum altitude + lookdown chaff effectiveness.

 

But, beyond that, your making this sound like some game balance issue, as if if ED makes CCM better they must "nerf" it in some other way (on that note ED claims the upped CCM during that few months was unintended so make what you will of that). The low altitude aiming errors themselves are realistic, thats just ground clutter doing its job, its not like this is some unrealistic "nerf"; the issue here is that the fundamental way it (and all RF MRMs in DCS) interacts with chaff is wrong. And its really noticeable.

 

And yes the AIM-120C is the best in game in terms of CCM, and thats also 100% irrelevant to the point. Nobody asked whether the AIM-120 is best relative to everyone else, thats pretty clear that it is; the question is whether the AMRAAM, absolutely (not relative to everyone else, as those should be adjusted too) should interact with chaff as it does, or all RF MRMs period.

 

1 hour ago, Max1mus said:

Of course im not surprised that this wasnt mentioned in here. Same as that whole ECM dodging thing. It does not seem like most of the posters in here have spent a lot of time doing Air to Air in DCS.

Yes, because most people really dont want to spend a lot of time testing stuff (or maybe dont know what/how to test), and those that do usually dont share much, and quite understandably. But I dont think it takes away from the issues of chaff in game. Nor does the fact that the players supposedly "haven't spent a lot of time doing Air to Air in DCS." mean anything. A bug report is a bug report.

[DCS FIGHTER PILOT]

5 hours ago, Max1mus said:

 

In the latest changelog, a thing called "low altitude tracking errors" was introduced. This allows specificly the AIM-7 and AIM-120 to be defeated in different ways compared to the previous patch. The R-27 was affected by this for a long time, but arguably to a lesser extent.

So that’s why it seems as if my AMRAAMS are missing even more. I was sure that this had something to do with it but I was not 100% certain. This coupled along with the 120’s relatively poor chaff resistance at the moment makes DCS feel like an arcade game right now where all one has to do is drop a few pieces of chaff and the missile goes stupid. 
 

With that said, ultimately, what is the most realistic behavior we can see with ARH missiles in DCS? Am I wrong and is it close now or is there much to be desired? To elaborate, how many pieces of chaff, how much notching, terrain masking, etc., would it take to truly make an Aim-120 go stupid?

Edited April 22, 2021 by DCS FIGHTER PILOT

[SgtPappy]

6 hours ago, Max1mus said:

To add to the whole "uninformed" point. As usual with these rage threats, most posters dont understand the changes ED makes and how that changes the effect of missiles on the fight, perhabs with the exception of posters like Noctrach, who fly in groups that spend a lot of time testing said missiles.

 

In the latest changelog, a thing called "low altitude tracking errors" was introduced. This allows specificly the AIM-7 and AIM-120 to be defeated in different ways compared to the previous patch. The R-27 was affected by this for a long time, but arguably to a lesser extent.

 

Of course im not surprised that this wasnt mentioned in here. Same as that whole ECM dodging thing. It does not seem like most of the posters in here have spent a lot of time doing Air to Air in DCS. ED surely understands that with how many new players have entered DCS recently, the forums and platforms like hoggit will be filled with this sort of stuff. Its not any different in other sims or games.

 

I read about the low altitude error being introduced into the AIM-7 and AIM-120 logic.  I was very pleased to read that! It seems very interesting but I do not exactly know what it does. Is it supposed to simulate the sidelobe clutter interference at low altitude from the illuminating radar? It appears that ED's efforts at improvement since there is now a distinction with low altitude missile guidance vs. older missile logic which seemed to just go for chaff when looking down in situations that range-gating should solve. This is a positive step in the direction toward realism.

 

While your points are valid, I can't shake the feeling that you may have missed the point or did not read through the whole thread and are dismissing the posts based on the conclusion that the posters don't know what they're talking about (it's a lot of pages to get through, understandably). The issue which has been posted in the many tracks and videos here, it is undeniable that there is something wrong with blinking ECM + chaff when it comes to missile guidance. I fly almost exclusively air to air in the 80s servers and have witnessed many AIM-7's simply miss a hot aspect F-14 that's just popping chaff and banking/turning a bit from side to side from 3 nm away, hot, looking up. This is consistent, reproduceable and the same exact thing happens for the AIM-120's, SD-10s, etc. But maybe that's not exactly what you're arguing against. If so, I apologize but would like some clarification.

 

 

Edited April 22, 2021 by SgtPappy

[nighthawk2174]

1 hour ago, DCS FIGHTER PILOT said:

So that’s why it seems as if my AMRAAMS are missing even more. I was sure that this had something to do with it but I was not 100% certain. This coupled along with the 120’s relatively poor chaff resistance at the moment makes DCS feel like an arcade game right now where all one has to do is drop a few pieces of chaff and the missile goes stupid. 
 

With that said, ultimately, what is the most realistic behavior we can see with ARH missiles in DCS? Am I wrong and is it close now or is there much to be desired? To elaborate, how many pieces of chaff, how much notching, terrain masking, etc., would it take to truly make an Aim-120 go stupid?

 

When hot or cold, even right up to the notch, and especially if the target is moving quickly chaff should have very little to no effect on missiles like the 120/SD10/54/77.  The chaff bundle will fall outside of the res cell to quickly, and fall into the doppler filters, and the amount of time it takes to bloom wouldn't help in the matter.  Were talking probably in the range of 1000-1500m/s of decel on chaff. It seems monopulse systems such as the 120/7/27 should also have some benefits in that they have the ability to determine there are multiple targets in the res cell and would allow them to implement any electronic based CCM quicker.  For the amraam its data link would help further, if it's getting updates as far as were aware it should allow it to reject false contacts (such as chaff or an unintended target such as a friendly) in favor of the host radars target.  This would also help it in getting through the notch.  Even if the missile gets notched or break lock somehow happens with chaff if the host radar still has the target then it should still be able to get the missile close enough that notching/chaff based break lock becomes essentially impossible.  Hec currently the missile once chaffed (maybe even notched not 100% sure) won't reacquire.  Chaff if to be used needs to be used in extremely large amounts in an essentially continuous stream while in a high-g maneuver, to increase the bloom rate, into the notch.  In theory chaff always being in the res cell could increase miss distance enough to allow you to survive a proxy detonation.  maybe even a miss if the warhead/fuze range is small (not really the case for many missiles).  Some texts (and rlf pilots) have indicated possible utility in throwing off rapid requisition attempts if your notch isn't perfect although this seems to be more true for static sam radars than missile radars that are always moving.   Ultimately though there's a reason western jets all moved too towed decoys.

[Max1mus]

8 hours ago, nighthawk2174 said:

When hot or cold, even right up to the notch, and especially if the target is moving quickly chaff should have very little to no effect on missiles like the 120/SD10/54/77.  The chaff bundle will fall outside of the res cell to quickly, and fall into the doppler filters, and the amount of time it takes to bloom wouldn't help in the matter.  Were talking probably in the range of 1000-1500m/s of decel on chaff. It seems monopulse systems such as the 120/7/27 should also have some benefits in that they have the ability to determine there are multiple targets in the res cell and would allow them to implement any electronic based CCM quicker.  For the amraam its data link would help further, if it's getting updates as far as were aware it should allow it to reject false contacts (such as chaff or an unintended target such as a friendly) in favor of the host radars target.  This would also help it in getting through the notch.  Even if the missile gets notched or break lock somehow happens with chaff if the host radar still has the target then it should still be able to get the missile close enough that notching/chaff based break lock becomes essentially impossible.  Hec currently the missile once chaffed (maybe even notched not 100% sure) won't reacquire.  Chaff if to be used needs to be used in extremely large amounts in an essentially continuous stream while in a high-g maneuver, to increase the bloom rate, into the notch.  In theory chaff always being in the res cell could increase miss distance enough to allow you to survive a proxy detonation.  maybe even a miss if the warhead/fuze range is small (not really the case for many missiles).  Some texts (and rlf pilots) have indicated possible utility in throwing off rapid requisition attempts if your notch isn't perfect although this seems to be more true for static sam radars than missile radars that are always moving.   Ultimately though there's a reason western jets all moved too towed decoys.

 

And what about jamming, in combination with chaff? Red flag pilots talk about jammers that "get him to the merge" against AIM-120Cs.

 

None of us here have any clue how effective which jammer with how much chaff at which speeds and angles is against which modern missile. But we know its a thing, its in one of the first sentences in the wikipedia article on chaff.

 

To add to that: A Serbian MiG-29A (no jammer, and very little chaff on board!) defeated a 5 mile AIM-120 launched head on from 20.000ft, fully supported. The F-15 pilot in the interview mentions how he was trained to expect this, should have launched more missiles, and should have maneuvered in anticipation of the missiles missing, to prepare for a merge.

 

He overshot and the MiG got away.

[Harker]

 To add to that: A Serbian MiG-29A (no jammer, and very little chaff on board!) defeated a 5 mile AIM-120 launched head on from 20.000ft, fully supported.

I recently asked an IRL fighter pilot friend of mine "is it possible to survive an AMRAAM shot from 6 NM away? If so, how?" Without getting into much detail, he explained that, if you time your defensive turn perfectly, you can take advantage of the interception logic of the missile and make it overshoot. It's not easy, obviously, and the chances of failure are high, but this was all to say that there is a small chance to survive by kinematically defeating the missile, which sounds exactly like what this MiG did.

He cannot comment on ECM, other than to say that its effectiveness depends a lot on the ECM and ECCM used by the two fighters. An ECM technique can have almost zero effect, if it's not the correct one or if the other platform is using the correct ECCM to counter it. Or, if used correctly and without ECCM to counter it, it can render radar useless. Depending on the jammer and the HMI, the operators have to dance around each other's techniques or the jammer does it by itself.

For chaff, he simply said that it's only effective in certain circumstances, since target selection algorithms can easily reject chaff in most cases, which is consistent with what people say in this thread.

[nighthawk2174]

2 hours ago, Max1mus said:

 

And what about jamming, in combination with chaff? Red flag pilots talk about jammers that "get him to the merge" against AIM-120Cs.

 

None of us here have any clue how effective which jammer with how much chaff at which speeds and angles is against which modern missile. But we know its a thing, its in one of the first sentences in the wikipedia article on chaff.

 

To add to that: A Serbian MiG-29A (no jammer, and very little chaff on board!) defeated a 5 mile AIM-120 launched head on from 20.000ft, fully supported. The F-15 pilot in the interview mentions how he was trained to expect this, should have launched more missiles, and should have maneuvered in anticipation of the missiles missing, to prepare for a merge.

 

He overshot and the MiG got away.

Considering that specific ECM techniques have had to be developed for monopulse seekers I can't really see the kind of ECM we have in game having much effect.

In the case of the situation you listed there's no way to know what happened it could have guided properly but failed to detonate there's a whole slew of possibilities.  Based on the description of the event it sounds far more likely that there was a missile failure than it getting chaffed or notched.

[Poulopot]

Thank you guys! I hope ED is going to listen to you and apply a significant buff on US missiles. Their russian bias is blatant, DCS always depicts US planes and missiles as the underdog, outdated and underperforming compared to russian gears.

[GGTharos]

4 hours ago, Harker said:

I recently asked an IRL fighter pilot friend of mine "is it possible to survive an AMRAAM shot from 6 NM away? If so, how?" Without getting into much detail, he explained that, if you time your defensive turn perfectly, you can take advantage of the interception logic of the missile and make it overshoot. It's not easy, obviously, and the chances of failure are high, but this was all to say that there is a small chance to survive by kinematically defeating the missile, which sounds exactly like what this MiG did.

 

He's probably talking about the last ditch defense, which is not what that MiG-29 did, or if it did, we wouldn't know about it.  What that F-15 pilot did do is launch at that MiG-29 when it was about to notch, and it did notch - it was not a 'head on' shot, it was a 'snap down' shot.  The last ditch defense is not really a kinematic defeat in this case, there are other things that factor in.

5 minutes ago, Poulopot said:

Thank you guys! I hope ED is going to listen to you and apply a significant buff on US missiles. Their russian bias is blatant, DCS always depicts US planes and missiles as the underdog, outdated and underperforming compared to russian gears.

 

That's a silly statement.  The Russian missiles are doing every bit as poorly.

[nighthawk2174]

13 minutes ago, GGTharos said:

 

He's probably talking about the last ditch defense, which is not what that MiG-29 did, or if it did, we wouldn't know about it.  What that F-15 pilot did do is launch at that MiG-29 when it was about to notch, and it did notch - it was not a 'head on' shot, it was a 'snap down' shot.  The last ditch defense is not really a kinematic defeat in this case, there are other things that factor in.

Yup the last ditch defense with chaff to potentially increase miss distance is absolutely a possibility.  In the case of the 29 we don't really know what happened so its not really a datapoint that's usable.

 

13 minutes ago, GGTharos said:

That's a silly statement.  The Russian missiles are doing every bit as poorly.

Agreed their eating chaff and the ECM bug just as badly as the US ones are.