Apart from Home on Jam missiles, is there any counter against self protection barrage noise jamming?

[Ronny]

Barrage noise jamming is the only form of screen jamming, it is often used by support asset such as EA-6B, EA-18G, B-52J. Unlike deceptive jamming which often used tricks to imitate the transmitted pulse of adversary radar, noise jammer often try to overwhelm the radar receiver with white noise.
In case of stand off support noise jammer then radar can deal with them by several ways such as:
- using sidelobes canceller/blanker (in case support jammer jamming from sidelobes region, the radar can turn their null toward that direction and just ignore the jammer)
- overwhelm the jamming signal strength with radar signal strength aka burn through (as tactical aircraft get closer to radar station, their return get stronger while support aircraft jamming signal is still the same because these one stay at standoff range, at a certain point, radar can burn through jamming signal)

In case of self protection noise jamming, the common way to deal with them is:
- Launching missile in Home on Jam mode (in this mode, missile just follow the direction of the jammer, similar to how AGM-88 engage a radar)

But currently, with the advance in technology, the jammer doesn’t need to be carried on aircraft. Jammer can be small enough to fit inside towed decoys (such as ALE-55, ALE-70) or cruise missiles (such as MALD-X, SPEAR-EW). Eventhough the jammer in these packet are a lot smaller and weaker than jammer on aircraft, they can always produce jamming signal a lot more powerful than the skin return of the aircraft (unlike standoff jammer) because they can stay inside radar main lobe and they can get close to target similar to the targets they protected
. So what are the other option to deal with stand in/self protect noise jammer ?

 

[P-STICKNEY]

The traditional first choice, going back to the 1950s, is to tune the RADAR's transmit / receive frequency out of the jammer's bandwidth. Most noise jammers don't transmit through their entire frequency band - it spreads the power on a particular frequency band thin, which means burn-through occurs further out. One way to cover the full bandwidth is to sweep the jamming signal through the bandwidth. A Frequency Agile radar can get past this by changing frequency randomly. I got out of the business before LPI turned into hardware, but I wouldn't be surprised if there are signal processing tricks that would work.

 

[Ronny]

The traditional first choice, going back to the 1950s, is to tune the RADAR's transmit / receive frequency out of the jammer's bandwidth. Most noise jammers don't transmit through their entire frequency band - it spreads the power on a particular frequency band thin, which means burn-through occurs further out. One way to cover the full bandwidth is to sweep the jamming signal through the bandwidth. A Frequency Agile radar can get past this by changing frequency randomly. I got out of the business before LPI turned into hardware, but I wouldn't be surprised if there are signal processing tricks that would work.

I don't mean spot or sweep noise jamming but barrage noise jamming (jamming across the whole band width) though.
Regarding the power out put, it seem like self protection noise jamming is insanely efficient even with much lower jammer gain and weaker jammer transmitting output

The radar that can burn through standoff jamming from 575 km will do so against stand in jamming from 21 km

 

[Scott Kenny]

I don't mean spot or sweep noise jamming but barrage noise jamming (jamming across the whole band width) though.
Regarding the power out put, it seem like self protection noise jamming is insanely efficient even with much lower jammer gain and weaker jammer transmitting output

The radar that can burn through standoff jamming from 575 km will do so against stand in jamming from 21 km

(images and calculations deleted for space)

Plus, most glide bombs reach farther than 21km these days, so even if the EA18G is jamming in close it can blast whatever it is having to jam from farther than that radar can burn through the noise.

 

[Ronny]

Plus, most glide bombs reach farther than 21km these days, so even if the EA18G is jamming in close it can blast whatever it is having to jam from farther than that radar can burn through the noise.

Just a side note,
the spec for radar in both case is similar to SPY-1 radar
But in the standoff case, I use a high power, high gain jammer, something like ALQ-99
In the stand in jamming case, I use very weak low gain jammer (gain of only 3dB and transmitting output of only 10W), something like ALE-55 fiber optic towed decoy.
It just seem that from the calculation stand in/self protection jamming is surprisingly effective, like too good to be true, but math doesn't lie. So I'm trying to figure out of there is any other way to deal with barrage noise jamming

 

[Vanessa1402]

Plus, most glide bombs reach farther than 21km these days, so even if the EA18G is jamming in close it can blast whatever it is having to jam from farther than that radar can burn through the noise.

If jamming is that good, why bother with stealth fighter

 

[Scott Kenny]

If jamming is that good, why bother with stealth fighter

Stealth gives you other advantages, like not having to jam and reveal your existence. "Special Forces" ninja stuff.

 

[Vanessa1402]

Stealth gives you other advantages, like not having to jam and reveal your existence. "Special Forces" ninja stuff.

If stealth aircraft use their radar then their position are revealed anyway.
AN/SPY-1 radar can detect a golf ball size target from 150 km, these stealth aircraft will be detected from very far, much further than burnthrough range here

 

[Scott Kenny]

If stealth aircraft use their radar then their position are revealed anyway.
AN/SPY-1 radar can detect a golf ball size target from 150 km, these stealth aircraft will be detected from very far, much further than burnthrough range here

LPI is a thing.

 

[Vanessa1402]

LPI is a thing.

LPI mostly reduce sidelobe power level, if the radar doesn't look at you then it can work.
If the beam point at you, then your RWR can still detect the radar.
Otherwise, SEAD will be impossible once PESA radar were introduced

 

[Ronny]

After a bit of research, it appear to me that one way to deal with stand in jammer in your main lobe is by using main lobe canceller (similar to side lobe canceller, just that the null is in the main lobe). I think the only disadvantage for this method would be that the jammer and the targets must be separated by some distance, otherwise they will both be inside the null and therefore invisible.
@stealthflanker : do you have any idea on how to calculate the null width? I assume that it is narrower than the beamwidth?


This is notching technique

 

[Ronny]

Another plausible way is to use angle tracking along with passive ranging




Passive ranging might not be very useful if the jammer are detached from the aircraft in case of MALD-J, SPEAR-EW. But in case the jammer are on board such as ALQ-184, ALQ-131 or towed right behind the airplane such as ALE-55, ALE-70, then passive ranging could be rather useful

 

[Scott Kenny]

If your towed decoy has enough separation and antenna to give a direction to the jamming, you can use the plane's onboard antennas to triangulate with the towed decoy.

 

[Ronny]

I don’t think towed decoy have enough stability for angle measurement, they also don’t have enough separation from the main platform

 

[Scott Kenny]

I don’t think towed decoy have enough stability for angle measurement, they also don’t have enough separation from the main platform

100m is plenty of separation for sound measurements, with radio you can also do signal phase on top of just time-of-receipt.

 

[overscan (PaulMM)]

Changing your own direction of travel generates separation much more easily though.

Barrage noise jamming is really not that great an idea. You are trading denial of direct range measurement for easy angle tracking and making yourself a target for any home-on-jam missiles. You also give away information {Look at me! high value target over here!).

Whatever amount of power you can generate in your self-protection jammer, spreading it over a wide range of frequencies will give less power than concentrating it in a smaller band. Spread-spectrum radars which operate over a wider bandwidth are typically thought to make barrage jamming impractical, as its not possible to flood a wide enough spread of frequencies.

There are more sophisticated deception ECM techniques which can produce phantom targets, deceive the enemy as to your position and break radar lock-ons. All of these make more sense in most situations I think.

 

[Ronny]

100m is plenty of separation for sound measurements

I think that only work because sound travel very slow. For radio wave, the time to travel 100 meters probably too negligible

with radio you can also do signal phase on top of just time-of-receipt.

You need very stable fixed antenna to measure phase different though. When the position and angle between the pair of antenna are fluctuating, it not quite practical to use interferometry

 

[Ronny]

Barrage noise jamming is really not that great an idea. You are trading denial of direct range measurement for easy angle tracking and making yourself a target for any home-on-jam missiles. You also give away information {Look at me! high value target over here!).

If the jammer is on board of the aircraft, I totally agree with you. However, in case the jammer are on a drone or cruise missiles, it seem like noise jamming is the best option. Not only it can shield others target. It also able to drag a bunch of HoJ missiles toward the decoy

 

[Scott Kenny]

I think that only work because sound travel very slow. For radio wave, the time to travel 100 meters probably too negligible


You need very stable fixed antenna to measure phase different though. When the position and angle between the pair of antenna are fluctuating, it not quite practical to use interferometry

The U2s carried a system in the pods on each wing that did the triangulation, and they operate at altitudes that make the angle between the two pods almost identical.

PELSS, Precision Emitter Location Strike System.

 

[Ronny]

The U2s carried a system in the pods on each wing that did the triangulation, and they operate at altitudes that make the angle between the two pods almost identical.

PELSS, Precision Emitter Location Strike System.

PLSS calculate distance by TDOA between multiple aircraft, not triangulation in 1 aircraft though

 

[Vanessa1402]

Best counter is to run, these decoys can't keep up with supersonic fighters. Once they run out of fuel, you re engage

 

[A_Random_Guy]

The question you really should be asking is what do you lose by performing barrage jamming?

By performing barrage jamming you deny yourself the ability to concentrate power in certain narrow bands, splitting your power and making it easier for the enemy to overcome it. It's an incredibly crude and inefficient way of performing EW.

You have a fundamentally limited transmission power and you have limitations on oboard power generation. So when faced with high power threats more targeted jamming is superior in just about every situation I can think of.

 

[Ronny]

The question you really should be asking is what do you lose by performing barrage jamming?

By performing barrage jamming you deny yourself the ability to concentrate power in certain narrow bands, splitting your power and making it easier for the enemy to overcome it. It's an incredibly crude and inefficient way of performing EW.

You have a fundamentally limited transmission power and you have limitations on oboard power generation. So when faced with high power threats more targeted jamming is superior in just about every situation I can think of.

What you say is correct, but the hard part to deal with is the stand in jamming part (whether done by a decoy or a pod). Due to the close proximity, their output almost is always much higher than the skin reflection. Even with massively powerful radar like SPY-1, burn through is barely possible at visual distance

 

[DWG]

The question you really should be asking is what do you lose by performing barrage jamming?

By performing barrage jamming you deny yourself the ability to concentrate power in certain narrow bands, splitting your power and making it easier for the enemy to overcome it. It's an incredibly crude and inefficient way of performing EW.

You have a fundamentally limited transmission power and you have limitations on oboard power generation.

Which is not to say you couldn't still combine both barrage jamming and selective jamming, it just puts an upper limit on your power budget.

 

[Vanessa1402]

Apologize for hijack the thread but do radar have any electronic counter counter measures to deal with DRFM jammer?. Are red air fighter in red flag equipped with DRFM jammer?

 

[Ronny]

Best counter is to run, these decoys can't keep up with supersonic fighters. Once they run out of fuel, you re engage

Run away expose your rear to enemy, which have very significant IR signature