arthuroA 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, have 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.”
arthuroIn the CAS role I agree but to join another aircraft there is already a “sky policing mode” is integrated in the rbe2 since the F1 standard to take the shortest/most efficient route and to vector the rafale in the good position when intercepting something. An HMS would not bring a lot more for the price and the complexity added.
arthuroA direct satcom datalink is in the pipe for the 5th batch also. (source a former DSI issue)
HMS would be good to have but keep in mind that this item could be relatively quickly integrated if needed by the AdA or another customer. In fact the rafale was already tested with an HMS from thales earlier in his development.
In my personal opinion with the mica-ir an HMS is less critical for the rafale as if the “EM BVR” option fail (due to jamming for instance) you can imediatley switch to the “IR option” well before the merge (LOAL capibility now operational with the F3).
With full around multi sensor fusion coverage it seems very unlikely that a threat could sneak to the merge undetected. To sum up, SA achieved through multi sensors fusion give you the time to anticipate and elaborate a tactic avoiding you the necessity to go autmaticly to the merge.
arthuroActive cancelation is not advertised (due to its sensitive nature) and all developments concerning it (see posts above from in the french budget) don’t mention it directly and talk about discretion demonstartors. But all the specialized press including A&Cosmos knows what its really about.
arthuroHere is the scan page about this program…
arthuroAlso, they state “independent to other spectra developments” does the system not use SPECTRA at all, or does it imply that SPECTRA will gain other modes of jamming and detection in addition to the active cancellation(with or without SPECTRA)?
It is not mention if the future demonstrator will use spectra to use active cancelation although this is implicitly stated as they make the precision that new modes/improvements will emerge independently from this feature (which is the case for every batch). So most probably yes spectra will be used for AC.
Second point : they mention “other unspecified features” to achieve stealth. I am pretty sure they talk about plasma stealth as there were several articles in A&C talking about experimental work on this feature in direct relation with the rafale. I remember (that was a few years ago) that they intended to apply this technology in one of the late 2010’s rafale batch. Not very difficult to make the link when reading this new article.
>>>For the record and for those whoa are not up to date with this problematic in relation to the rafale development :
article from Bill swetman
The Rafale EW suite, known as Spectra, is one of the most powerful systems installed on a fighter aircraft and is intimately associated with the unique approach to stealth and survivability designed into the Rafale. Dassault executives describe the Rafale as discreet rather than being stealthy in the sense of a F-22. To avoid detection, it combines avionics, tactics, and reduced radar reflectivity with some techniques that have not been directly revealed and are apparently unique.
The first element of discretion is that Spectra’s receiver system and the FSO help detect and track targets without using radar. Spectra incorporates a radio-frequency (RF) detection system, a missile-approach warning sensor, and a laser-warning system and provides full 360-degrees coverage. The RF detection subsystem uses prominent square-section antennas, mounted on the lower corners of the engine inlets and in the rear of the fin-top pod, covering 120 degrees each. The receiver antennas use interferometric techniques to measure a signal’s angle of arrival within less than 1 degree and are designed so that they do not have a large radar-cross-section (RCS) contribution.
The Rafale is also designed to use terrain masking, particularly at night or in bad, weather when visually cued short-range surface-to-air weapons are less effective. With its maneuverability and a high degree of cockpit automation, the fighter is designed to fly a terrain-avoidance/threat- avoidance profile at 5.5 g and 100 feet in altitude. The RBE2 and a terrain-referenced navigation system, using stored terrain data, are used to provide redundant flight guidance.
Rafale makes extensive use of radar-absorbent material (RAM) in the form of paints and other materials, Dassault engineers have said. RAM forms a saw-toothed pattern on the wing and canard trailing edges, for instance. The aircraft is designed to so that its untreated radar signature is concentrated in a few strong “spikes,” which are then suppressed by the selective use of RAM.
Spectra’s active jamming subsystem uses phased-array antennas located at the roots of the canards. Dassault has stated that the EW transmit antennas can produce a pencil beam compatible with the accuracy of the receiver system, concentrating power on the threat while minimizing the chances of detection.
But there is more to Spectra than conventional jamming. Pierre-Yves Chaltiel, a Thales engineer on the Spectra program, remarked in a 1997 interview that Spectra uses “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 [low-observable] aircraft.” When asked if he was talking about active cancellation, Chaltiel declined to answer.
Earlier this year, Thales and European missile-builder MBDA disclosed that they were working on active-cancellation technology for cruise missiles and had already tested it on a small unmanned aerial vehicle, using a combination of active and passive techniques to manage radar signature. This revelation makes it considerably more likely that active cancellation is already being developed for Rafale.
Active cancellation is a LO technique in which the aircraft, when painted by a radar, transmits a signal which mimics the echo that the radar will receive – but one half-wavelength out of phase, so that the radar sees no return at all. The advantage of this technique is that it uses very low power, compared with conventional EW, and provides no clues to the aircraft’s presence; the challenge is that it requires very fast processing and that poorly executed active cancellation could make the target more rather than less visible.
The complexity of active cancellation could account for Spectra’s high price tag, estimated in 1997 as “several billion francs” (equivalent to the high hundreds of millions of US dollars) for research and development. One of four Rafale prototypes was dedicated to Spectra tests, along with a Falcon 20 flying testbed. Four new large anechoic chambers were built to support the Spectra project, including one which is large and well equipped enough to operate the complete system in a fully detailed electromagnetic environment.
Spectra’s RF systems are backed up by a laser-warning system, an optical missile-launch-warning system, and a full range of expendable countermeasures. There is no towed decoy system.
****
MBDA-France has been developing active stealth systems that attempt to cancel the radar return from an airframe by transmitting a second signal of equal frequency and amplitude to the genuine return. Unlike Ram, this technique retains is effectiveness at low and medium frequencies, where the efficiency of passive stealth technology tends to decline.
In 1999, the company conducted ground tests using a C-22 target drone fitted with an experimental active-stealth system, and flight tests conducted using ‘testbeds’ (probably C-22s) were carried out at the Centre d’Essais des Landes range at Biscarosse in southwest France.
Possible applications for active stealth measures include the nose, seeker, wing-leading edges and engine air inlets of future missiles. France hopes to use such technology on the mid-life update of the Scalp EG air-to-surface cruise missile, and in next-generation supersonic missiles. Studies have been underway since the mid-1990s, when designers investigated a possible stealthy variant of the Apache with a redesigned fuselage of flattened triangular cross-section.
arthuroI think that the people who are deciding to invest millions in that field are aware of what they are doing. I don’t think that a simple poster could decently challenge anything with a simple sentence when you know all the years and money poured in that field. It is quite mysterious for us even if we can understand the basics of how it works. But I don’t think that anyone here is competent enough to seriously bring a thorough point of view otherwise you would be working in a research lab and won’t right on an open forum like this one.
It is quite useless to pontificate I think as a real thorough knowledge in this area.
arthuroQuite some news in A&Cosmos today…
A “stealth rafale demonstartor” will be funded (according to the very official 2010 french defense budget) to increase its stealth capabilites. According to air&Cosmos the solution that will be adopted is active stealth and will be developed by the CEA and the DGA. This capability should be operational with the 5th batch of the rafale program and is independent to other spectra developments. They also mention other techniques but unspecified. I’ll try to scan the article this week end.
development is to start this year.
arthuroAbout the square dance I had the opportunity to ask a rafale pilot at the latest Paris air show. He told me that only the rafale could perform it as well thanks to its very good FCS design.
I must say I don’t take his word as mine as I was never able to compare to other aircrafts. I also humbly don’t know what is so special with it. But that what he said.
One thing that was said to me by former mirage 2000 demo pilot in 2007 (paris air show) about dassault’s FCS (mirage 2000, rafale) is that you could see the quality and the precision of it compared to other aircrafts during demos by the ability to roll perfectly on the axis without rolling ass. This was confirmed by A&C with radar datas : the M2K and the rafale had the best “symetrical” flight path. Of course he is not neutral but there is perhaps some truth in it ?
arthuroHere is a video of Sebastien Loeb (6 time world champion of WRC) having a ride in the rafale and visting St dizier AFB. starts around 3 min I think…
For the record you can see Lcl grandclaudon at 5’50 (the guy from whom the ATLC polemic arrived-the author of the press conference)
http://www.dailymotion.com/video/xcqbzo_en-vol-avec-l-armee-de-l-air-5-6_tech
Serge Dassault interview afterward…The first thing that his father did after coming back from Buchenwald camp where he was deported as jew after WW2 was to ask for a drawing board in his room.
Also a not so well known fact and for everyone culture one of Marcel Dassault’s school mate at Sup aero engineer school in 1913 (Toulouse) was Michail Guverich the founder of MIG.
Quite unexpected !
http://fr.wikipedia.org/wiki/Institut_supérieur_de_l’aéronautique_et_de_l’espace
arthurojackjack,
You don’t know what you are talking about. Please learn from other posters and try to understand.
arthurojackjack,
you should go back to the board where you come from. I don’t blame your opinion as everyone is free but I blame your stupidity. Your posts are some of the lowest standard I’ve ever seen. It rounds in circle and you are unable to assimilate some basic infos which is provided to you nor you are capable to elaborate your theory. Change your attitude and grow up.
arthuroThere is a lot of speculation with of course no tangible evidences.
A hint would take into account dassault’s experience in that matter. Certainly they have weighted the pros and the cons before taking a decision. They didn’t take this kind of decision randomly and they are certainly more skilled than anyone on this board.
Besides in one of the recent leak of the latest FAB evaluation the rafale was deemed to have the best aptitude to evade radars compared to the SH and gripe NG.
But it is not a VLO aircraft of course
arthuroI found an amazing rafale demo video : great camera work…Probably the best I’ve seen to date. Really it has something more than other demo video.
The video features some massive instantaneous maneuverability. Very very impressive I think…
Roll rate in quite jaw dropping too…2’52 for instance.
link bellow :
arthuroTime is short to renew the fleet
March 19, 2010The choice of the new fighter advanced combat aircraft comes to an end as no surprise and in accordance with the will of the government. O Rafale vai custar caro, mas menos do que tem sido especulado, alguma coisa entre R$ 5,5 e R$ 6,5 bilhões, com chances de redução ao longo do tempo, afirmam assessores do ministro da Defesa, Nelson Jobim. The Rafale will be expensive, but less than has been speculated about something between $ 5.5 and $ 6.5 billion[ without maintenance costs i think], with chances to reduce over time, say aides to Defense Minister Nelson Jobim.The preference for France offer, including 36 supersonic and supplies, was on the rise since the announcement of the shortlist, which included the U.S. fighter F-18 and also the Gripen NG, Swedish.
In the Planalto, there were always negative remarks about the tangle of laws that hinder the United States sales of military systems by means of contracts with a clause for transfer of technology and uncertainty about the project NG. In addressing the delivery of knowledge, the use of the word “unrestricted” in the offer of Dassault, took advantage on the “necessary”in Boeing’s one . The proposal from Saab, to participate in the final development of its aircraft, did not exceed the scope of the agreement with France, a partnership that points in different directions, including a bilateral front in international affairs. The concrete fact, real life is that the decision can wait no longer – the process accumulates 10 years of delay and the Brazilian Air Force (FAB) begins to feel the pressure of the crisis: the fleet needs to be turned off from 2015 when the Mirage 2000C / B purchased by President Lula in France will leave the scene. On the timing of its own aircraft industry, four years is, indeed, tomorrow. Whatever the chosen aircraft, it is no longer possible to guarantee the security compatibility between time and need. That is the subtext of the message of the High Command issued to Defense Minister Nelson Jobim, two days ago
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