AIM-54 Chaff Resistance

[DCS FIGHTER PILOT]

Lately, a lot of my aim-54s have missed their target because they were spoofed by chaff. I do realize that at the moment in DCS countermeasures work on a basic level, either they work or they don’t, their is a probability assigned to each missile getting spoofed. In the future will we see better aim-54 performance against chaff or is this what it was actually like in real life?

[razo+r]

What if you disregard the missile performance for now and start shifting your focus towards DCS and the mechanics behind the curtain?

[draconus]

Or maybe the target was notching and the chaff was the best radar return source at hand?

[DCS FIGHTER PILOT]

Or maybe the target was notching and the chaff was the best radar return source at hand?

 

He was. It just always seems to work though. I’m not sure if it would be that effective in reality. The best defense against a missile is to kinetically defeat it, not to decoy it.

[draconus]

He was. It just always seems to work though. I’m not sure if it would be that effective in reality. The best defense against a missile is to kinetically defeat it, not to decoy it.

Notching alone is legit technique and works IRL but it's hard to perform perfectly, not so reliable and thus very dangerous. Chaff is not that much effective in modern warfare I heard.

 

It's DCS'ism that pilots feel confident enough to evade missiles, risking only virtual lives and go into the merge.

[DCS FIGHTER PILOT]

Notching alone is legit technique and works IRL but it's hard to perform perfectly, not so reliable and thus very dangerous. Chaff is not that much effective in modern warfare I heard.

 

It's DCS'ism that pilots feel confident enough to evade missiles, risking only virtual lives and go into the merge.

 

Will DCS eventually see these more “realistic” countermeasures? I would think that the older AIM-54 variants are easier to decoy but the later c I would imagine, would be much harder.

[razo+r]

Notching alone is legit technique and works IRL but it's hard to perform perfectly, not so reliable and thus very dangerous. Chaff is not that much effective in modern warfare I heard.

 

It's DCS'ism that pilots feel confident enough to evade missiles, risking only virtual lives and go into the merge.

 

In real life they use different type of chaff to be more effective against certain radars.

[TOMCATZ]

As far I know, chaffs are still a challenge- even for modern radar. Yes - it`s frustrating, but seems to be correct in DCS.

So I fly my cat as a "mobile SAM station". If I got a kill- nice. If not... who cares. I was always happy when I was able to land on deck safely- no kills, but sure that some guys had to change their pants. :megalol:

[nighthawk2174]

Against any PD radar (the 54's included) chaff is naturally filtered out once it drops below the Vgate. Additionally the amount of time it takes chaff to actually reach its full RCS can be 3+ seconds at which time its already fallen below said Vgate and is going to be separated from the main aircraft as well potentially by quite some distance. Not to mention if you chaff just so happens to not be perfectly cut for the 54's radar frequency that will also decrease its effectiveness as well. One also has to wonder if the 54 uses such systems as RCS edge tracking, where if the rcs of a target rapidly increases due to chaff the radar will track the leading edge of the contact. This anti-chaff method was first developed in the late 50's early 60's.

[Fri13]

Against any PD radar (the 54's included) chaff is naturally filtered out once it drops below the Vgate. Additionally the amount of time it takes chaff to actually reach its full RCS can be 3+ seconds at which time its already fallen below said Vgate and is going to be separated from the main aircraft as well potentially by quite some distance.

 

 

One also has to wonder if the 54 uses such systems as RCS edge tracking, where if the rcs of a target rapidly increases due to chaff the radar will track the leading edge of the contact. This anti-chaff method was first developed in the late 50's early 60's.

 

You do know those are contradictions to each others?

 

If chaff would simply drop below Doppler speed filter and become so on useless, why to have anything to go against them when in few seconds the chaff is already non effective?

 

The challenge with chaff is not about its speed in air, but its size and its area. You instantly jam the radar itself with it.

 

There are new filters like your mentioned, but it is logic that if target keeps moving to right at speed X and it has done so last 10 seconds, and you suddenly get larger contact that jams you, keep looking at the predicted position based the last 10 second vector and speed for a given time.

 

Chaff is not a "larger target" that just "drops in speed rapidly". It is far more.

Why you do not release chaff even in training because you jam the airspace for long period with it.

[nighthawk2174]

They're not contradictions there will still be a short time period where the chaff can be seen by the radar and not filtered out and if your dropping a lot of chaff in a steady stream you can create the apparent effect of an increased RCS. In particular for Pulse radars, PD this effect would be more limited.

 

Additionally we're talking about self defense chaff bundles here the amount of time they remain at a density to actually have a noticeable impact on radar detection ranges is not going to be anywhere near the amount needed and used by chaff corridor missions (thousands of lbs of chaff not the couple of lbs - if even that- for the small bursts used on tactical aircraft). Besides there could be a whole plethora of reasons not to use chaff such as not wanting to affect civilian radar systems which aren't built to handle chaff. Or it could be as simple as costs savings.

 

Edit

 

Just as an example lets say you have a chaff bundle that takes 1 second to slow from 550kts to 0kts. In that 1 second the chaff would move 465ft (but still moving ever more rapidly away from the launching aircraft) and still be detectable for 461 ft if -I did my math right- viewed from the rear, if we assume the Vgate is +-45kts. Now obviously as we get closer and closer to the beam the shorter the time between launch and dropping below that 45kts. If the radar as a resolution of 1° for example at 8 miles it would be 736ft wide if it was centered on the aircraft, now one could have it so the target is not centered (conical scan / monopulse) or just set ahead of the target as a way to minimize the time chaff can be seen.

Edited March 5, 2020 by nighthawk2174

[Fri13]

You do know that chaff released by aircraft at speed ie. 250 m/s (900 km/h) has chaff to scatter to size of fighter (and hence huge RCS) in just 50 ms time. But at that same 50 ms time the chaff speed has already below 20 m/s (72 km/h).

 

So you do understand that chaff wouldn't have ever any effect on anything, not even in the ~30 ms time period when it is passing a common speed filter?

 

Yes, we are talking about microseconds and milliseconds about speeds and areas, where radars could be made perfectly ignorance about chaff ever used.

 

The chaff is very interesting how it alters PD radar speed gate regardless the chaff is stationary.

Example SAAB has lots of research about chaff effectiveness against modern radars.

[TOMCATZ]

In RL chaffs will be filtered by radar systems. But a chaff cloud is still an obstacle- filtered or not. Your systems need a lot of computer power to calculate it.

 

Unfortunally all is higly classified. We won`t find any sources or infos about it.

 

But I would say that the Question is simple:

 

If chaffs are useless in modern Warfare, why every air force still use it? For me the answer is simple: Because it works well.

 

 

 

Interesting links:

 

http://wx.db.erau.edu/faculty/mullerb/Wx365/Chaff/chaff.html

 

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=2ahUKEwjC_LvQ7ILoAhUNuaQKHV3mBcEQjRx6BAgBEAQ&url=https%3A%2F%2Fwww.sto.nato.int%2Fpublications%2FSTO%2520Meeting%2520Proceedings%2FRTO-MP-097-I%2FMP-097(I)-12.pdf&psig=AOvVaw2ZYRg5dRKhLrCdxY7Jfr7c&ust=1583480754769434

 

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/E338317110A8E9AAC96CA70F93A37773/S0960129513000686a.pdf/analysis_of_the_doppler_frequency_feature_of_aero_deception_activepassivejamming.pdf

 

 

Cheers

 

Tom

Edited March 5, 2020 by TOMCATZ

[Bananabrai]

What my impression of electronic warfare in DCS is:

 

It could be way better. Things are classified, thats ture.

But still the basics of RADAR emission, reflection, etc. count for classified stuff, as for cellphones, as for garage openers, ... (the list is infinite)

 

I recently thought about Chaff in DCS. It would require additional computing power, but if you consider for ex. one Chaff (-cloud) as an object, it would work.

 

It would just need a few paramters.

 

- Health, termined by time and wind, because the metal foil gets displaced, disturbed/seperated and falls to the ground

- The RF band it reflects/absorbes best (different type of Chaff)

 

That would already be way better and enough for us. Done.

 

Same for ECM, ground bound RADAR, airbone RADAR, ... Nobody needs to know real frequiencies, PI, PRF, power and whatnot.

[captain_dalan]

Lurking here

[SgtPappy]

It makes sense that the chaff should not be treated quite like a flare as it is now - however as I understand (especially for 70's and maybe 80's missiles), if the target is beaming a radar perfectly, near the ground and dropping chaff, it should give no return different from the ground.

 

This would have the effect of putting the defender in that noise band on the AWG-9 that you see when you turn off the Doppler filter.

 

Did radars at this time (especially in the early AIM-54A) have the ability to track the leading edge of targets dropping chaff? Is this technique applicable to targets beaming near the ground?

 

Correct me if my understanding is incorrect.