Aviation Week & Space Technology

Podcast: Developments In Stealth And Counterstealth

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It’s a cat-mouse-game as old as warfare -- one military tries to move unseen, the other side tries to spot the enemy before he knows it. Senior Defense Analyst Dan Katz, Managing Editor Graham Warwick and Executive Editor Jim Asker discuss the latest in stealth technology and counterstealth. Plus: Why did the U.S. use the expensive, stealthy B-2 bomber against the Islamic State insurgents, who do not have sophisticated air defenses?

 

 

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Discuss this Video 11

on Jan 23, 2017

Really excellent podcast!

on Jan 23, 2017

Thanks!

Jim Asker
Executive Editor

on Jan 23, 2017

Wait for the Counter/Counter Stealth coming to a supplier near you soon.

on Jan 23, 2017

Thanks for your pod cast on stealth and counter stealth – very interesting – as was Dan Katz’s “state of stealth” series.

IMHO, some suggestions for future articles:
• It was briefly mentioned in the podcast about how stealth requires trade-offs, and the F-22, T-50, J-20 have taken different decisions regarding these trade-offs. While the article series and the podcast explained the difference in the approaches for the F117 and B-2, I think an article highlighting the trade-offs that exist, what they actually are, and what different approaches have been taken with reference to the F-22, T-50, J-20 (and probably F-35) would be a very interesting illustration of the engineering compromises that stealth designs need to consider.
• I think you could do an equally interesting series of articles on IR stealth. The approaches of engines to reduce IR, low emissivity coatings, cooling air flows, direct line of sight blockage, and the evolution of IR missile countermeasures such as flares, DIRCM, and how they attempt to deceive IR missile sensors, and missile counter counter-measures, such as imaging, two-color, and long wave IR sensors. Then there are capabilities of aircraft based IR sensors such as IRST.
• It’s also often said stealth designs need to correctly balance different aspects of stealth, such as IR and RCS. No good being brilliant in one and poor in the other. Yet I have never seen an article that discuss this in any length. Almost universally “stealth” is used to mean low RCS and clearly this is given the priority, but what are the relative threats between the two and how does the mission of the aircraft and tactics affect these threats and hence the resulting balance? How does the range and capability of an IRST compare with a radar, for example?

on Jan 31, 2017

Thanks for the ideas!

Jim Asker
Executive Editor

on Jan 24, 2017

Thanks for an interesting time! I really enjoyed it.

I don't think you covered enough about the effect of ECM on stealth aircraft sensors range.

Some time ago I read that when the Eurofighter ECM was in war mode, an F-35 could detect it at 30km. That is a pretty drastic reduction in range and largely puts in on par with a conventional aircraft using a powerful radar.

The reverse situation for the Vostok D/E radar is described in a documetn on the Australian Air Power site. It is a fascinating read.

"The manufacturer claims a detection range of ~40 nautical miles against the F-117A Nighthawk, or other types with similar VHF band RCS, in a jammed environment, and 190 nautical miles in an unjammed environment......"

So this means that all ranges in the Australian Air Power Document are likely to be when in ECM mode.

on Jan 27, 2017

Hi Tarjei,

Thanks! Glad you liked the podcast.

It is true that ECM can reduce detection ranges of radars. Sometimes manufacturers quantify by how much, but often not. If they do, in order to have apples to apples comparison they have to provide certain specifics: not just the target but power of the jammer and if it’s onboard the target aircraft. A “jammed environment” often means the target is protected by a standoff jammer, in which case the range at which it is standing off must be considered.

In the case of the Vostok-3D, the manufacturer claims acquisition of a the F-117 at 10km altitude at:
350 km in the absence of jamming; and
57 km in "jammed conditions" which the manufacturer defines as a 200W/MHz jammer at 200 km.

However, the effectiveness of ECM assumes the jammer knows where to send the signal. Therefore, while I’m not sure what “war mode” means, I’m highly skeptical about the Typhoon’s ECM being able to reduce the F-35’s detection range significantly.

In order to do this, it’d have to either: 1. use a cover jamming signal to increase the noise and hide its return signal or 2. actively cancel its return signal with a 180-deg phase shifted, matched waveform.

In both cases, it would need to know where the F-35 is. To be effective, noise jammers have to concentrate their power into a small angle; sending their power in all directions means they won’t generate much noise in the threat radar. For active cancellation, the appropriate cancelling waveform is going to be different from every angle, because the radar return is different from every angle.

Since the F-35 has a low RCS, the Typhoon’s radar would have a hard time detecting it at long range. The Typhoon could try to detect the F-35’s radar emissions, but the F-35’s APG-81 is an AESA with extensive low-probability of intercept functionality, so the Typhoon is unlikely to even know it’s been targeted until the missile launches. Additionally, if it can't detect and identify the F-35's waveform, it can't hope to compose a matched waveform for active cancellation.

And if the Typhoon sends out a noise signal in all directions, or even a very general direction, plus over the APG-81’s entire frequency range, its not only spreading its power way out, but also broadcasting its presence.

In the “jammed environment” above, the jammer is an escort jammer, not on the target aircraft, so it will likely stay at the outer edge of the IADS’s kinematic engagement range, so it’s ok if its jamming is noticed. When you’re goal is not to be detected, putting out a jamming signal, particularly a noise jamming signal, is more dangerous.

Typhoon’s have trained with the F-22s on several occasions. The reports from those exercises indicate the Typhoons always get taken out at long range. Some reports say if they start in a dogfight, the typhoon sometimes can win, but when they start from long range, they never get within sight of the F-22s. And I’ve yet to hear of the F-22s having problems detecting Typhoons. The F-35’s radar is even more advanced than the F-22’s, albeit smaller.

The typhoon has a capable ECM, but against a stealth aircraft with an LPI radar, it’s unlikely to know where to send the jamming signal and that means it's unlikely to be able to jam effectively. But it would have a chance to jam the missile once launched.

on Jan 26, 2017

It was the invulnerable weapons system. France had more than any other European nation. It was very expensive to produce and maintain.

That weapons system died by the droves at Crecy.

Even Achilles had his heel.

on Jan 26, 2017

Thanks for the podcast!! :)

on Jan 26, 2017

And thank you! We appreciate the feedback.

--Jim Asker
Executive Editor

on Jan 27, 2017

You are welcome. even if I do not agree with some editorial line of AWST I find it very interesting.
Have good day!

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