How difficult to detect AESA and LPI radars?

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armedupdate

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Unread post18 Mar 2017, 06:09

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How capable is EW systems like the Barracuda in detecting AESAs and other LPI radars? I believe the Rafale in a excercise spoofed a S-300 radar in the Greek excercise(which PESAs)

Because with modern radar techniques, a radar can hide very well within background noise and it's pulses are all wideband and behave in a coded pattern which can impossible to track without knowing enemy classified information.
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Unread post18 Apr 2017, 17:08

I'm bumping this thread because much of the answer can be found in a blog series created by one of the posters here. I, however, cannot remember the website or the name of the poster. This is not SSGTMac's 'elements of power' I am looking for but the site covers the basics of aerodynamics, radar, ECM, ECCM, Stealth, the whole nine yards. It's a great resource and I myself am looking to get more info from it.
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Unread post18 Apr 2017, 17:29

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Unread post18 Apr 2017, 19:27

That's the awesome website of member garrya:

viewtopic.php?t=29022
"Those who know don’t talk. Those who talk don’t know"
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Unread post18 Apr 2017, 20:40

botsing wrote:That's the awesome website of member garrya

I thought it was garrya, but I wasn't sure. The technical detail and source list is impressive to say the least.


To answer to OP question however, the Barracuda is the ONLY system on Earth (AFAIK) that has made the public claim of detecting and jamming an AESA under operation-like conditions. It jammed an APG-77 (F-22) back in 2009 while onboard the CATBird. Counter claims usually range from "We don't know if the F-22 was using LPI mode" or "We don't know the range."

Counter arguments are that we don' know if the F-22 has any non-LPI modes. It may be 100% LPI 100% of the time. It is always described as having LPI characteristics, not modes. And as to the range argument? Who cares. Nothing else has ever so much as detected the transmissions.

Now things to keep in mind are that the radar on the F-35 started with the modes and functionality of the F-22 and were improved upon. The same is true of the ECM suite. This means the Barracuda might have only been able to jam the APG-77 because the systems are "related" and it knows what to look for and on top of the relationship the Barracuda uses all more advanced technology as both systems were made by the same company using state-of-the-art tech 20 years apart.

We really just don't know, but one thing is for sure. To detect the focused, low-powered, frequency-hopping transmissions of a modern AESA you likely need to start with the tech required to generate them. Since the best AESA tech that Russia has bragged about is no more capable than a 1990's MSA (granted at half the size, MiG-29 vs F-15E) from the U.S. I doubt they have the sensitivity to detect U.S. AESA transmissions.
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Unread post19 Apr 2017, 08:54

Correct on all accounts. When people talk about "LPI modes", it's clear sign they don't know anything about the subject. LPI is not a mode or modes, but rather set of features and characteristics that radar or other RF system has. These features are for example these:

- wide total bandwidth
- frequency hopping
- complex signal modulation
- power management (use only as much power as required for each task)
- very low sidelobes (leaked RF power outside main beam)
- irregular or (pseudo)random scan pattern
- pulse compression
- high duty cycle (low peak power, high average power)
- high sensitivity (requires less output power for same result)
- coherent detection and high processing gain (radar knows exactly the frequency used and signal modulation, enemy does not)

All modern radars have some or even all of these features and characteristics. Then there is huge differences in implementation of each of these features. A modern AESA radar might well be 10 times better in each of these characteristics than some older PESA system. The net result is that the AESA radar is far more difficult to detect than the PESA radar even though both have all the same LPI features. ESM system that can easily detect the PESA radar from 100 km away might be totally unable to detect the AESA radar even if it was sitting next to it. Advanced ESM system that can detect the AESA radar from certain distance would be able to detect the PESA radar much further away with ease. To detect latest AESA radars, one needs extremely good ESM system to detect them, they are that good.
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Unread post19 Apr 2017, 20:17

sprstdlyscottsmn wrote:I'm bumping this thread because much of the answer can be found in a blog series created by one of the posters here. I, however, cannot remember the website or the name of the poster. This is not SSGTMac's 'elements of power' I am looking for but the site covers the basics of aerodynamics, radar, ECM, ECCM, Stealth, the whole nine yards. It's a great resource and I myself am looking to get more info from it.



botsing wrote:That's the awesome website of member garrya:

viewtopic.php?t=29022

Thanks for the compliments guys
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Unread post20 Apr 2017, 01:06

....sort of on the subject; what would a F-35A look like on another F-35A (opposing) sensor (radar?) display??? from pick a range 200nm, 20nm, 2nm, 0.2nm,....relative to the size of a soccer ball (an international size dimension)! :wink:
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Unread post29 Sep 2018, 10:41

sprstdlyscottsmn wrote:
botsing wrote:That's the awesome website of member garrya

I thought it was garrya, but I wasn't sure. The technical detail and source list is impressive to say the least.


To answer to OP question however, the Barracuda is the ONLY system on Earth (AFAIK) that has made the public claim of detecting and jamming an AESA under operation-like conditions. It jammed an APG-77 (F-22) back in 2009 while onboard the CATBird. Counter claims usually range from "We don't know if the F-22 was using LPI mode" or "We don't know the range."

Counter arguments are that we don' know if the F-22 has any non-LPI modes. It may be 100% LPI 100% of the time. It is always described as having LPI characteristics, not modes. And as to the range argument? Who cares. Nothing else has ever so much as detected the transmissions.

Now things to keep in mind are that the radar on the F-35 started with the modes and functionality of the F-22 and were improved upon. The same is true of the ECM suite. This means the Barracuda might have only been able to jam the APG-77 because the systems are "related" and it knows what to look for and on top of the relationship the Barracuda uses all more advanced technology as both systems were made by the same company using state-of-the-art tech 20 years apart.

We really just don't know, but one thing is for sure. To detect the focused, low-powered, frequency-hopping transmissions of a modern AESA you likely need to start with the tech required to generate them. Since the best AESA tech that Russia has bragged about is no more capable than a 1990's MSA (granted at half the size, MiG-29 vs F-15E) from the U.S. I doubt they have the sensitivity to detect U.S. AESA transmissions.



Interesting.


I have a question about Barracuda suite. It can make electronic warfare, and we know that it can help to realize jamming on radars in X band, but is it able to do it on radars in long band, type vhf or uhf?

I would be very impressive. Somebody know something about this?
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Unread post29 Sep 2018, 14:42

falcon.16 wrote:
sprstdlyscottsmn wrote:
botsing wrote:That's the awesome website of member garrya

I thought it was garrya, but I wasn't sure. The technical detail and source list is impressive to say the least.

To answer to OP question however, the Barracuda is the ONLY system on Earth (AFAIK) that has made the public claim of detecting and jamming an AESA under operation-like conditions. It jammed an APG-77 (F-22) back in 2009 while onboard the CATBird. Counter claims usually range from "We don't know if the F-22 was using LPI mode" or "We don't know the range."

Counter arguments are that we don' know if the F-22 has any non-LPI modes. It may be 100% LPI 100% of the time. It is always described as having LPI characteristics, not modes. And as to the range argument? Who cares. Nothing else has ever so much as detected the transmissions.

Now things to keep in mind are that the radar on the F-35 started with the modes and functionality of the F-22 and were improved upon. The same is true of the ECM suite. This means the Barracuda might have only been able to jam the APG-77 because the systems are "related" and it knows what to look for and on top of the relationship the Barracuda uses all more advanced technology as both systems were made by the same company using state-of-the-art tech 20 years apart.

We really just don't know, but one thing is for sure. To detect the focused, low-powered, frequency-hopping transmissions of a modern AESA you likely need to start with the tech required to generate them. Since the best AESA tech that Russia has bragged about is no more capable than a 1990's MSA (granted at half the size, MiG-29 vs F-15E) from the U.S. I doubt they have the sensitivity to detect U.S. AESA transmissions.


Interesting.

I have a question about Barracuda suite. It can make electronic warfare, and we know that it can help to realize jamming on radars in X band, but is it able to do it on radars in long band, type vhf or uhf?

I would be very impressive. Somebody know something about this?


Check this out...
viewtopic.php?f=38&t=26802
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Unread post29 Sep 2018, 19:11

popcorn wrote:Interesting.

I have a question about Barracuda suite. It can make electronic warfare, and we know that it can help to realize jamming on radars in X band, but is it able to do it on radars in long band, type vhf or uhf?

I would be very impressive. Somebody know something about this?

Check this out...

viewtopic.php?f=38&t=26802

But on this page, they are talking about Aesa features, not about Barracuda suite...
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Unread post18 Oct 2018, 18:42

Salute!

Great thread.

Hornet has a very good overview of a few of the radar characteristics making the new systems very clever.

Of interest should be the widely implemented "spread spectrum" - type systems we use every day with our cell phones. No more multi-plex channels using frequencies as I grew up with in the 50's and 60's. Make no mistake, we still use frequency division techniques, especially the optical systems. But RF freqs are a different breed of cat.

Digital technology zoomed in the late 60's and in the 70's. An article I read in the early 60's in Popular Electronics proposed "pulse code modulation" versus the old AM and FM systems. The invading aliens did not detect our PCM systems and were ambushed when they landed their craft! Neat SCI-FI idea, huh? With the PCM, you might get a signal above background, but without lottsa work it would still come across as white noise that could be from electric motors, power plants and so forth.

So we can use digital bursts at widely separated frequencies, or simply use our unique "chip" signature in the digital burst we send out and receive. Just run a moving filter across "white noise" and look for your chip signature that is nearly the same power as background galactic noise. You will find it at really low S/N numbers.

Of course, power plays. The power density is a function of time as well as raw output. It's like a spike heel shoe where the PSI of the spike is a thousand pounds but the young lady weighs 110 pounds.

I can only imagine how far we have come since I was a nugget operating the latest and greatest systems. Back in mid-60's we had a super system in the 106 and VooDoo. Our radar could change frequencies at a zillion times a second. We knew the pulse coding and new frequency, so our receiver was ready to pick up the return. We had "internal lobing" for our track mode. The old systems used a mechanical cone that moved to get a steering signal, and the enema EWO could figure this out and spoof us. The new system used phase shifts detected by slots in the waveguide, and did not allow the enema EWO know our scan freq without a lotta work.

The frequency hopping was so good that one day we practiced on a Buff up at Grand Forks. Great debrief. The EWO was very good and "stole" our range gate and had minor success moving our antenna angle. So my RIO finally said, "Screw it, going to 'Fast min', becasue 'fast max' was prohibited when certain satellites were overhead. Jamming went away and the EWO told us that it looked like white noise on his screen. We did this without transistors!!!!
++++++++++++++++++=

So imagine what things could be like today?

Switching times with current solid state devices is down in the femto second range, and we routinely operate home electronics at the giga hertz frequencies with the data packets coded and such. Wi-fi, cell phones, GPS, and the beat goes on.

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Unread post18 Oct 2018, 21:15

I had no idea that older radars used such technologies. Thanks for the history lesson, Sir! :salute:
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Unread post18 Oct 2018, 23:26

Salute!

NP, Spurts. Was blessed to fly two really great avionics jets and a few years in the Dragonfly. The Deuce and VooDoo were good for me, but nothing like the Viper and Sluf.

We had hydraulically tuned magnetrons for both the "6" and VooDoo that rapidly compressed the suckers to change transmitter frequency. Solid state technology was just taking off in a giant way, and just three years after my checkout, we had that "giant leap for mankind" Funny, but my EE prof in 1962 stated that we couldn't use transistors up at UHF frequencies due to their frequency reponse as amplifiers. Heh, heh. 'course the digital capabilities of the solid state devices as well as some other characteristics shot his opinion all the hell. So by 1970, my A-7D NAVWD computer integrated a super INS, data for the HUD and projected map display, plus provided cosmic bomb accuracy. I think the only tubes we had in the Sluf were for the radar transmitter, the radar CRT and "stroke" Marconi HUD symbology.

The "Normal' setting for our radar and the one in the "6" spread the pulses out a 1,000 megahertz or so, best I recall, using a pseudorandom pattern. Not sure of the tune rate. "Fast Min" was faster between pulses with a shorter max range and I can't recall "Fast Max" numbers. And don't forget we had a nice IRST in all three of our ADC interceptors. Pulse doppler was just being tested, and I think the YF-12 had an experimental one that later wound up in the Tomcat.

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Unread post18 Oct 2018, 23:54

Gums wrote:ulse doppler was just being tested, and I think the YF-12 had an experimental one that later wound up in the Tomcat.

Gums sends...


Sortof. They're very different radars as far as I can tell.

ASG-18 (and TWO IRSTs)
anasg18.jpg


AWG-9
radar.jpg


And the ASG-18 was a "look-down, shoot-down" radar (don't know if it has to have PCM capability for that). One test included a YF-12 flying at 74,000 feet at Mach 3 and hitting a JQB-47 flying at 500 feet, 33 miles away.

"THE ASG-18, BY JIM EASTHAM

Author's Note: Jim Eastham has had an amazing career. As a test pilot for
Hughes Aircraft, he was responsible for testing most of the interceptor fire control
systems deployed by this country during the Cold War. Later, he moved to
Lockheed and was intimately involved in the YF-12 flight test program. This is
one of his stories.
Early in the testing and development of this system, we, Hughes, knew
what the power output was and that it could be dangerous if one was
exposed to the output of the transmitted signal. Also, it had a very high PRF
(pulsed repetition frequency) which was approximately 250 kilohertz, which is
about 250,000 pulses per second at an average power of about 5 kilowatts.
This was many times greater than the output of contemporary systems. Consequently,
many safety procedures were instituted.
The first was to put out red-rotating lights and each light fixture was
connected to a very long length of yellow plastic ribbon material. The rule
was that when the transmitter was turned on, the red rotating light was
turned on and great caution was observed to make sure no one got within
the field of the scan of the transmitted signal.
During one of the tests, one of the Lockheed mechanics walked up to
the yellow plastic ribbons, picked it up and started walking across in front of
the aircraft. Everyone immediately started yelling at this individual and asking
him if he wasn't aware that he could be injured by the radar? This character
pulled himself up and announced that they, Lockheed, had built the F-94
and consequently, "they knew all about radar!"
Now to put this in perspective, the F-94 used the original E-1 system
,which was in reality a converted General Electric tail-gun radar from a B-29.
This little system had an average power-output of 16 Watts, which was approximately
0.3-percent of the power of the ASG-18! Now this can be stated
another way and that is that the ASG-18 was 387 times more powerful than
the original E-1 radar!
Now one can't argue with stupidity; therefore, Dick La Fleur, Hughes project
manager, devised a demonstration which could show the power-output and
demonstrate that one could be injured by the radar. He had the facility-maintenance
people get a standard 4x8-foot sheet of plywood and it was placed
directly in front of the aircraft and the ASG-18 antenna was pointed directly at
the sheet of plywood. Also, the antenna was not scanning at that time.
The Lockheed flightline mechanics thought this was rather humorous
and they were making a joke of this demonstration until a brown spot began
to appear on the plywood, and then it began to smoke. After a short while,
the wood actually began to burn and flames began to appear on the spot
that was being radiated!
This demonstrated that the radar was potentially dangerous and made
the point that it was a real hazard to get up close and in front of the system
when it was turned on! Actually, we got a bit of an "over-kill" and no one
would get near the system when it was turned on!
I might add that when the word filtered up to Beale and the tanker
boom operators heard about his test, it created a bit of anxiety and we
would always inform them that the radar was turned off before we refueled.
"There I was. . ."
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