Active Missile Look Down Notch Width Seems Excessive

[nighthawk2174]

So I've been doing some more BVR recently and I feel that this change:

Quote

introduced ground clutter model, missile notching now depends on target/clutter signals ratio, range of blind velocities depends on geometry of intersection of seeker beam and ground.

has either been not entirely effective or no longer works.  Essentially one of the issues with the older model was that notching was way to effective, in both look up and look down.  Especially if there was no terrain behind the target it should not have been as easy as it was, or if the terrain was well beyond the maximum detection range of the seeker.  When the fix first went live it seemed to have worked very well and in both look up and look down active missiles were exceptionally hard to notch. However in recent testing it seems that it is now way to easy to notch a missile while it is in look down.  It seems this is a factor of the size of the notch itself.  And that there is no attempt by the missile to require after being notched.  The missiles just go into 1g steady flight a few seconds after the moment its notched with no attempt to reaquire.

Spoiler

https://imgur.com/a/cwrV2dq

 

Most cases in the tracks below had the missiles notched at ~100kts of closure.  Where they then proceeded to fall from the 3-4 they were pulling down to 1g over the course of a second or so.

From testing it seems most missiles have a notch width of ~100kts±15kts in look down, with look up being a lot less.  This is as bad as early HPRF only radars such as the F14.  This seems exceptionally high for a very modern radar with medium PRF modes. Especially if there is no clutter or the ground clutter is 20+Nmi away.  Especially considering technologies available to PD monopulse seekers like this, or STAP.  Or even just the fact that you can still track with a range gate if the MLC is sufficiently separated or if the S/N ratio is favorable enough.  Which should happen for an active seeker only a few miles from a target with terrain possible 10's of miles away.

 

ED has said that ontop of this S/N is now simulated?  This doesn't appear to be the case.  The fact is that that different terrains have different clutter amounts.  A city will have significantly more clutter than the ocean, where all of the tests took place.  Yet the missile was still notched just as easy as over land and still with the huge notch.

Spoiler

 

 

 

Tacview-20210926-202038-DCS-TRAIN2.zip.acmi

Edited September 28, 2021 by nighthawk2174

[KenobiOrder]

To add to the range discrimination aspect, monopulse seekers can have exceptionally high range resolution. This would allow the radar to discriminate the target based on the nature of the range returns from the individual reflectors of the target. The ground return would be relatively uniform in range across its range of angles.

 

 

 

 

 

 

[Xhonas]

Interesting read ! The way that notching active missiles works in dcs right now feels like a meme, pass through the notch for half second and the spike instantly drops... i mean, seems waaayyy off compared to what i've heard around there... I have just anecdotes, but you provided some proof ! I hope that ED sees your post!

Edited September 29, 2021 by Xhonas

[85th_Maverick]

On 9/28/2021 at 6:11 AM, nighthawk2174 said:

From testing it seems most missiles have a notch width of ~100kts±15kts in look down, with look up being a lot less.

 

Show us how you'll be able to notch an AIM-120 (B or C, they're modeled the same) missile at +/-80kts closure (you said 100+/-15, I say you can only notch if below 20kts only if also flying very slow) in look down condition with all the chaff in the world and see what you get. And you say "with look up being a lot less". Huh...! You won't even notch a missile with all the chaff in the world if you are not below 20kts while hugging the ground, but if the missile sees you above the ground, you'll have mathematically zero chances of notching it! I think I've tried a lot more tests and scenarios than the testers did, but you can try! Please make a track of it (Tacview would be even better) and share it with us so we can confirm your claims and analyze. You complain that your active radar missiles lose track of the targets when they are notching over the ground? I find that they're actually more close to reality as they are simulated right now. You probably believe that the radar physics would allow these active radar missiles have some sort of alien tech in them and shouldn't lose the target in any condition. In fact, there are many conditions which still can't be overrun to have them lose targets. That's the way it is.

 

You are right that they should indeed lose targets that are notching over the ground with or even without dropping chaff if the geometric closure rate versus ground is at around 100+/-15 knots as you say, but that doesn't happen by far. It's closer to 0kts (I said 20kts maximum closure rate difference vs ground speed) and only if you also fly slow enough, you'll eventually be able to notch it with or without chaff. For the AIM-120B/C, the chaff does ZERO difference whatsoever, the only thing that works is flying slow with as close to zero closure rate as possible. So, you can't even notch them with 999999999 chaff thrown all in 1 second even if the missile is looking down at you and you're very close to the ground, but as for going up or having the missile look above the ground at you, notching it will happen in far less cases than the already mentioned one, otherwise said, less than zero chances if you will! I've done only a short test to prove this in the following tracks (after many tens of hours of trying other different stuff that also didn't work to have the missiles go for chaff or be notched). Now's your turn to prove what you've said! They are still quite highly resistant to notching conditions even in the best conditions and you want them worse?

Aim-120C vs beam notch vs chaff.acmi aim-120C vs beam notch vs chaff.trk

[nighthawk2174]

1 hour ago, 85th_Maverick said:

 

Show us how you'll be able to notch an AIM-120 (B or C, they're modeled the same) missile at +/-80kts closure (you said 100+/-15, I say you can only notch if below 20kts only if also flying very slow) in look down condition with all the chaff in the world and see what you get. And you say "with look up being a lot less". Huh...! You won't even notch a missile with all the chaff in the world if you are not below 20kts while hugging the ground, but if the missile sees you above the ground, you'll have mathematically zero chances of notching it! I think I've tried a lot more tests and scenarios than the testers did, but you can try! Please make a track of it (Tacview would be even better) and share it with us so we can confirm your claims and analyze. You complain that your active radar missiles lose track of the targets when they are notching over the ground? I find that they're actually more close to reality as they are simulated right now. You probably believe that the radar physics would allow these active radar missiles have some sort of alien tech in them and shouldn't lose the target in any condition. In fact, there are many conditions which still can't be overrun to have them lose targets. That's the way it is.

 

You are right that they should indeed lose targets that are notching over the ground with or even without dropping chaff if the geometric closure rate versus ground is at around 100+/-15 knots as you say, but that doesn't happen by far. It's closer to 0kts (I said 20kts maximum closure rate difference vs ground speed) and only if you also fly slow enough, you'll eventually be able to notch it with or without chaff. For the AIM-120B/C, the chaff does ZERO difference whatsoever, the only thing that works is flying slow with as close to zero closure rate as possible. So, you can't even notch them with 999999999 chaff thrown all in 1 second even if the missile is looking down at you and you're very close to the ground, but as for going up or having the missile look above the ground at you, notching it will happen in far less cases than the already mentioned one, otherwise said, less than zero chances if you will! I've done only a short test to prove this in the following tracks (after many tens of hours of trying other different stuff that also didn't work to have the missiles go for chaff or be notched). Now's your turn to prove what you've said! They are still quite highly resistant to notching conditions even in the best conditions and you want them worse?

Aim-120C vs beam notch vs chaff.acmi 1.13 MB · 0 downloads aim-120C vs beam notch vs chaff.trk 602.01 kB · 0 downloads

I attached an example tacview to the original post, its not the only tests I did, feel free to look at it.  There are at least 8 examples of notching the missiles in that track. https://imgur.com/a/cwrV2dq

Edited September 30, 2021 by nighthawk2174

[KenobiOrder]

1 hour ago, 85th_Maverick said:

Huh...! You won't even notch a missile with all the chaff in the world if you are not below 20kts while hugging the ground,

There are literally several examples of notching missiles where the ground isnt even close to the target and it's barely look down in those tacviews he posted. Notching right now is effortless and absurdly effective.

Edited September 30, 2021 by KenobiOrder

[85th_Maverick]

K, I'll check again then, maybe I'm not up to date with the latest modifications which might prove both of you guys are right, but half an year ago (may updates behind) it was exactly as in the tracks that I've provided!

[KenobiOrder]

6 hours ago, 85th_Maverick said:

but half an year ago

If you read his first post, you will note that this bug report is in response to the fix ED put in some time ago no longer working.

[nighthawk2174]

Yeah as I said in the original post when I first tested it was extremely hard even in look down, as it should be.  But recently I've noticed that it is now child's play to do this.

[Harker]

Yeah as I said in the original post when I first tested it was extremely hard even in look down, as it should be.  But recently I've noticed that it is now child's play to do this.

Yeah, it has become really easy to notch both missiles and radars (at least the F-18's) in look down conditions, even if the target is at high altitude, but below the horizon.

[KenobiOrder]

Any feedback on this?

[DCS FIGHTER PILOT]

Current behavior after the patch, you guys be the judges. 

NOTCH 1.trk NOTCH 2.trk NOTCH 3.trk

[KenobiOrder]

Yeah its ridiculous. I had hoped this patch would fix this but now it seems even easier to notch and chaff is now super effective again. I see no evidence of Range gating or SNR being used to prevent notching. Missile are being notched even in the most mild look down situations at 40,000ft.

Edited October 21, 2021 by KenobiOrder

[DCS FIGHTER PILOT]

46 minutes ago, KenobiOrder said:

Yeah its ridiculous. I had hoped this patch would fix this but now it seems even easier to notch and chaff is now super effective again. I see no evidence of Range gating or SNR being used to prevent notching. Missile are being notched even in the most mild look down situations at 40,000ft.

 

Yeah that's what I figured. No skill required to completely trash a 21st Century missile. 

[KenobiOrder]

Actually I am not so sure now, need to do more testing. My first tests were vs ace ai and they may have been doing some humanly impossible notch maneauver. Doing tests now where I try to notch ai fired amraam and I have not been successful once yet, even with an ass load of chaff. So maybe we jumped to conclusions too quickly. Not sure how your tests were done

Tacview-20211020-214303-DCS.zip.acmi

Tacview-20211020-214706-DCS.zip.acmi

[KenobiOrder]

Nevermind. It is definitely way too easy to notch even with the supposed improvements in this patch. Supporting with the data link seems to work, which is what I am doing in the shots that dont miss. But a simple turn to the beam seems to work almost every time, making it childs play to defeat the missile. You dont even need chaff. Very occasionally, the missile will re-aquire but its extremely rare.

Tacview-20211020-233647-DCS-17.zip.acmi

[GatorNutz]

22 minutes ago, KenobiOrder said:

Nevermind. It is definitely way too easy to notch even with the supposed improvements in this patch. Supporting with the data link seems to work, which is what I am doing in the shots that dont miss. But a simple turn to the beam seems to work almost every time, making it childs play to defeat the missile. You dont even need chaff. Very occasionally, the missile will re-aquire but its extremely rare.

Tacview-20211020-233647-DCS-17.zip.acmi 1.22 MB · 0 downloads

I have the same findings...notching is almost infallible after this patch.  I have a notching practice mission that I've flown after several updates (to use as a control).  I was able to notch all 15 AI-fired AIM-120Cs today (100%)...which I've never been able to do in the past.

My tests were done with me flying the F-16 (6 shots) and the F-14 (9 shots).  I was able to notch all AI fired AIM-120C using simple beam and chaff maneuvers.  All AI shots were look down (I was below the launching aircraft).

Edited October 21, 2021 by GatorNutz

[nighthawk2174]

1 hour ago, GatorNutz said:

I have the same findings...notching is almost infallible after this patch.  I have a notching practice mission that I've flown after several updates (to use as a control).  I was able to notch all 15 AI-fired AIM-120Cs today (100%)...which I've never been able to do in the past.

My tests were done with me flying the F-16 (6 shots) and the F-14 (9 shots).  I was able to notch all AI fired AIM-120C using simple beam and chaff maneuvers.  All AI shots were look down (I was below the launching aircraft).

 

Agreed this last patch seems to have made it worse.  I'd hoped that this issue would have been fixed but unfortunately it hasn't.  As I said in my original post notching should be very ineffective against a missile that almost certainly has specific countermeasures against this.  Such as STAP or the technique I linked.  The reduction in CCM against chaff is also an unpleasant surprise as once again chaff is waaay to effective against missiles.

Edited October 21, 2021 by nighthawk2174

[Oceandar]

It seems Phoenix is also affected. Tried in SP against it and with little maneuvering it was trashed.

[DCS FIGHTER PILOT]

I guess the folks over at ED just really like dogfighting? 

[Jack1nthecrack]

Do your tests in MP against other people, NOT AI! AI cheat, everything is a random dice roll in THEIR favor. I had an AI Su-30 notch me vertically against a blue sky at 5km in my Su-33. Doing tests against AI and then reporting the observations is not very scientific. 

[Hotel Tango]

Great post OP, i can't agree more. Notching -120 (and other modern missiles) right now in DCS is extremely easy. It's too reliable, to the point of invalidating almost any other defense maneuver. 
Notching one missile should be a fluke, not a rule...

[DCS FIGHTER PILOT]

15 minutes ago, Jack1nthecrack said:

Do your tests in MP against other people, NOT AI! AI cheat, everything is a random dice roll in THEIR favor. I had an AI Su-30 notch me vertically against a blue sky at 5km in my Su-33. Doing tests against AI and then reporting the observations is not very scientific. 

Clearly you did not watch my tracks. 

14 minutes ago, Hotel Tango said:

Notching one missile should be a fluke, not a rule...

Wonderfully said! 

[GatorNutz]

1 hour ago, Jack1nthecrack said:

Do your tests in MP against other people, NOT AI! AI cheat, everything is a random dice roll in THEIR favor. I had an AI Su-30 notch me vertically against a blue sky at 5km in my Su-33. Doing tests against AI and then reporting the observations is not very scientific. 

I used AI to fire missiles at me...I'm not firing against them.

[DSplayer]

11 hours ago, Oceandar said:

It seems Phoenix is also affected. Tried in SP against it and with little maneuvering it was trashed.
 

Nope. That’s the AI F-14’s AIM-54 employment problem. Problem with the AI and not the 54. Player fired 54s are fine. Player and AI AIM-120s are not.