Posted on 04/05/2010 6:03:19 AM PDT by sukhoi-30mki
A Stealthier Rafale?
Posted by Bill Sweetman at 4/5/2010 5:30 AM CDT
Our colleagues at Air & Cosmos report that the French government is funding a demonstration of improved stealth technology for the Dassault Rafale fighter, with a focus on active cancellation techniques. The story itself is not online but is being discussed at the Key Military Forum.
Active cancellation means preventing a radar from detecting a target by firing back a deception signal with the same frequency as the reflection, but precisely one-half wavelength out of phase with it. Result: the returned energy reaching the radar has no frequency and can't be detected.
It's quite as difficult as it sounds. Some reports have suggested that the so called SP-3 or ZSR-62 "radar jamming device" planned in the early days of the B-2 program was an active cancellation system. It did not work and was scrapped in 1987-88. In 2005, Northrop Grumman paid $62 million to settle a False Claims Act case involving the system.
This may not be the first French attempt to implement AC on the Rafale. At the Paris air show in 1997, I interviewed a senior engineer at what was then Dassault Electronique, about the Rafale's Spectra jamming system. He remarked that Spectra used "stealthy jamming modes that not only have a saturating effect, but make the aircraft invisible... There are some very specific techniques to obtain the signature of a real LO aircraft."
"You mean active cancellation?" I asked. The engineer suddenly looked like someone who deeply regretted what he had just said, and declined any further comment. (As Hobbes once put it after pouncing on an unsuspecting Calvin: "We tigers live for moments like that."*)
The fact that a new demonstrator is being contemplated suggests that the technology may not have been up to the job the first time round - but since AC depends on electronics and processing, that picture may have changed. MBDA and Thales, which absorbed Dassault Electronique and is now the prime contractor on Spectra, havs since confirmed that they are working on active cancellation for missiles.
The whole Spectra program has been a major venture, including the construction of four new indoor test ranges, including the colossal Solange RCS range discussed in Ares in 2007. That facility will probably play a major role in the new demonstrator program.
* It should be noted that Calvin's response was "Not for long you don't."
The problem I would think to be overcome is that there are many different types of radar. If the system has been improved enough to send back false signals to multiple radars and radar types at the same time, it could be something to keep an eye on!
But this system would have the same vulnerabilities as a true stealth aircraft has to a bistatic system.
Interesting. But if it works well, it would essentially give stealth to any aircraft? except for the bistatic system you mentioned?
Wonder when they'll finally settle for the A-12 "Flying Dorito" too?
Interesting concept. I also remember tests being performed for daytime visual stealth as well. Something about light and various spectrums of light being used to essentially make the aircraft “blend” into the sky.
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