The Rafale hidden beauties and its future

[Picdelamirand-oil]

GaN evolves in the X band

A GaN Spectra transmitter demonstrator is expected in 2014.

In UMS foundries’ laboratories, equally shared by EADS and Thales, a revolution is rising. Next year, a X-band gallium nitride (GaN) semiconductors production should be validated. This is a first in Europe.

Since that year, UMS had already succeeded in mastering the production of components operating in S-band GaN, aiming Thales Ground Master radars family’s market.

But the realization of X-band elements remained hitherto the preserve of the United States. For now, active antenna radars developed in Europe, as the RBE2-AESA of the Rafale, use gallium arsenide (GaAs) components as X-band hyperfrequencies amplifiers : "A same size GaN brings the promise of a gain factor of 5 on the power emitted" said the chief engineer of armaments Xavier Grison, the Directorate General of Armaments. The future of airborne radar is hence in balance on this technological revolution. "With the GaAs, the room for improvement is low and the current radars are already at their upper limit in terms of performance, "added the engineer.

GaN X-band components to be qualified in 2013.

For several years, favored by successive upstream studies programs (USP), the Directorate General of Armaments had promoted the emergence of this technology. The last USP dated, known as Ganymede, should lead to the realization of X-band components prototypes representative of those that will be used in an operational system. Under the current schedule, this step should be reached within two to three years. But next year, the GaN industrial process will already be qualified, which means that the manufacturing process will be mastered and the performance and reliability of the components will been clearly characterized.

Applications are yet to be found by UMS to penetrate wider markets for GaN components in order to ensure a significant workload for its plants.

Compared to GaAs, which was quickly needed in the wireless telecommunications, GaN components present fewer potential market outlets in civilian business. According to Xavier Grison, it will take at least five years before we see first operational applications of GaN on airborne systems.

Spectra improvement.

Rafale will undeniably benefits of GaN technology in short or longer term. Already an USP, called Incas (Integration of new capabilities to Spectra), examines the replacement of existing GaAs emitters by GaN ones. As part of this USP, a GaN Spectra transmitter demonstrator is expected for the end of 2014. The potential gains expected are increased emission power,increased efficiency, and a wider bandwith.

Again, the commissioning of such systems remains bound to the timing of Rafale evolutions which are not expected until the next decade. Even more futuristic, but also possible: replacing existing radar nose antenna by conformal ones, smart "skins" that could be easily spread over the cell combining radar, jamming, communications and other purposes ...

In the shorter term, DGA expects that GaN components could find their first operational applications in ground systems like anti-IED or other decoy systems jammers. For its part, the civilian industry could adopt this technology to develop power components for mobile phones base stations, for example. The space industry is also interested: ESA and CNES have helped fund some developments around the GaN components and their possible "spatial" applications, expecting to use them in future communication satellites. In Europe, UMS is the only chance to see the emergence of a completely independent industrial sector in the field of GaN. The challenge is important because, as they had done for GaAs, the United States do not hesitate to apply an embargo on GaN circuits.

On the British side, the RFMD factory (which provides, among others, transceiver modules used by AESA radars from Selex Galileo) managed to gain independence in the field of GaAs - but displays no desire to develop a GaN factory in Europe.

William Steuer

SPECTRA et ce que vous savez - Page 16 - Europe - AIR-DEFENSE.NET

 

[randomradio]

GaN evolves in the X band

A GaN Spectra transmitter demonstrator is expected in 2014.

In UMS foundries’ laboratories, equally shared by EADS and Thales, a revolution is rising. Next year, a X-band gallium nitride (GaN) semiconductors production should be validated. This is a first in Europe.

Since that year, UMS had already succeeded in mastering the production of components operating in S-band GaN, aiming Thales Ground Master radars family’s market.

But the realization of X-band elements remained hitherto the preserve of the United States. For now, active antenna radars developed in Europe, as the RBE2-AESA of the Rafale, use gallium arsenide (GaAs) components as X-band hyperfrequencies amplifiers : "A same size GaN brings the promise of a gain factor of 5 on the power emitted" said the chief engineer of armaments Xavier Grison, the Directorate General of Armaments. The future of airborne radar is hence in balance on this technological revolution. "With the GaAs, the room for improvement is low and the current radars are already at their upper limit in terms of performance, "added the engineer.

GaN X-band components to be qualified in 2013.

For several years, favored by successive upstream studies programs (USP), the Directorate General of Armaments had promoted the emergence of this technology. The last USP dated, known as Ganymede, should lead to the realization of X-band components prototypes representative of those that will be used in an operational system. Under the current schedule, this step should be reached within two to three years. But next year, the GaN industrial process will already be qualified, which means that the manufacturing process will be mastered and the performance and reliability of the components will been clearly characterized.

Applications are yet to be found by UMS to penetrate wider markets for GaN components in order to ensure a significant workload for its plants.

Compared to GaAs, which was quickly needed in the wireless telecommunications, GaN components present fewer potential market outlets in civilian business. According to Xavier Grison, it will take at least five years before we see first operational applications of GaN on airborne systems.

Spectra improvement.

Rafale will undeniably benefits of GaN technology in short or longer term. Already an USP, called Incas (Integration of new capabilities to Spectra), examines the replacement of existing GaAs emitters by GaN ones. As part of this USP, a GaN Spectra transmitter demonstrator is expected for the end of 2014. The potential gains expected are increased emission power,increased efficiency, and a wider bandwith.

Again, the commissioning of such systems remains bound to the timing of Rafale evolutions which are not expected until the next decade. Even more futuristic, but also possible: replacing existing radar nose antenna by conformal ones, smart "skins" that could be easily spread over the cell combining radar, jamming, communications and other purposes ...

In the shorter term, DGA expects that GaN components could find their first operational applications in ground systems like anti-IED or other decoy systems jammers. For its part, the civilian industry could adopt this technology to develop power components for mobile phones base stations, for example. The space industry is also interested: ESA and CNES have helped fund some developments around the GaN components and their possible "spatial" applications, expecting to use them in future communication satellites. In Europe, UMS is the only chance to see the emergence of a completely independent industrial sector in the field of GaN. The challenge is important because, as they had done for GaAs, the United States do not hesitate to apply an embargo on GaN circuits.

On the British side, the RFMD factory (which provides, among others, transceiver modules used by AESA radars from Selex Galileo) managed to gain independence in the field of GaAs - but displays no desire to develop a GaN factory in Europe.

William Steuer

SPECTRA et ce que vous savez - Page 16 - Europe - AIR-DEFENSE.NET

Do you have the image of the Rafale B02 with the GaN?

 

[Picdelamirand-oil]

Do you have the image of the Rafale B02 with the GaN?

It was a video

 

[randomradio]

It was a video

There.

 

[desimorty]

Meh, don't buy into the hype. EW is not unique or a monopoly of Rafale. Eventually other aircraft, will have their own advanced Jamming features.
AFAIK the F-22 goes. When within visual range, you can get a lock. The engines emit both radar signals back and give off heat source. Its not INVINCIBLE.
That being said, the Pak-FA takes into consideration-anti-stealth features to match F-22 something lockhead is waiting and developing upon. Once the Pak-FA does enter service, no doubt the F-22 will receive a new batch upgrade or MLU.

 

[Picdelamirand-oil]

Meh, don't buy into the hype. EW is not unique or a monopoly of Rafale. Eventually other aircraft, will have their own advanced Jamming features.
AFAIK the F-22 goes. When within visual range, you can get a lock. The engines emit both radar signals back and give off heat source. Its not INVINCIBLE.
That being said, the Pak-FA takes into consideration-anti-stealth features to match F-22 something lockhead is waiting and developing upon. Once the Pak-FA does enter service, no doubt the F-22 will receive a new batch upgrade or MLU.

There is difference between EW, smart EW, smartissimo EW.

 

[gambit]

@gambit

I've heard the F-35 uses active cancellation also, although restricted only in the X band from open source info. There was this article quoting a British F-35 pilot who claims the F-35 can create a 'wormhole', his words, and non-stealth aircraft can tag along for the ride without being detected. That leads me to believe the F-35's radar is capable of active cancellation.

Any idea if that's true?

The phrase 'active cancellation' can be misleading.

To start off...If you transmit a 'counter' signal with opposite polarization, etc...etc, and you successfully nullified the EM characteristics of the seeking pulse, that could be construed as 'active cancellation'. The problem here is that in the process, YOU became a transmitter, no matter how briefly.

True 'active cancellation', which the US is working on, occurs at the materials level, meaning the aircraft allows the seeking radar signal to impact its skin, allows surface penetration, and somehow destroys the radar signals sub surface. What is that 'somehow' ? I have a few ideas, but I am not saying what they are. With this method, I do not transmit. There will be a minute amount of reflection at the initial contact of the radar signals to the aircraft's skin. No absorber is perfect so there will always be some specular reflections. But since the bulk of the radar signal is allowed to penetrate, these specular reflections will be absorbed or at least masked by background noise in the atmosphere. The analogy is paper and water, or use a sponge, if you wish. Water is absorbed into the paper via capillary action. A basic amplifier circuit can act the same way for electricity. That is clue enough for you.

As for what an F-35 pilot claimed the jet's systems can do, it would be the first method of 'active cancellation', which an 'old crow' like meself considers to be more like EW. An AESA array is required.

Looking Inside Scanned-Array Radar Signal Processing

By subdividing the antenna into sub-arrays, the system can transmit a number of beams simultaneously,...

An AESA system is the only true simultaneous operations radar system because it can logically partition its main array into many sub-arrays, in other words, an AESA antenna instantly becomes several AESA antennas.

In the above example, one of the four arrays have nine simultaneous radar beams. You just have to figure out which.

Subarrays partitioning and choreography software is what make the F-22 and F-35 lethal. No one knows the exact technical details of what those AESA systems can do. With an AESA system, one EW beam can be highly directional, focusing on the specific direction of the enemy radar threat, one beam can be for communication, another beam can perform volume search. All at the same time.

 

[desimorty]

There is difference between EW, smart EW, smartissimo EW.

Source: The Rafale hidden beauties and its future | Page 3

Yea, I know my signals, whether passive or active, its not the absolute solution. Its the same. It depends on information, and counter information. This is taken into account. Its still a method of jamming.

 

[randomradio]

True 'active cancellation', which the US is working on, occurs at the materials level, meaning the aircraft allows the seeking radar signal to impact its skin, allows surface penetration, and somehow destroys the radar signals sub surface. What is that 'somehow' ? I have a few ideas, but I am not saying what they are. With this method, I do not transmit. There will be a minute amount of reflection at the initial contact of the radar signals to the aircraft's skin. No absorber is perfect so there will always be some specular reflections. But since the bulk of the radar signal is allowed to penetrate, these specular reflections will be absorbed or at least masked by background noise in the atmosphere. The analogy is paper and water, or use a sponge, if you wish. Water is absorbed into the paper via capillary action. A basic amplifier circuit can act the same way for electricity. That is clue enough for you.

Thanks. But this is not 'active cancellation'. What you are referring to is destruction of signals. It is a passive cancellation if you will. From what we already know, the Russians already use a combination of RAM/RAS and plasma to achieve the same on PAK FA.

Through open sources, there are three major known methods of treatment of signals for stealth.

One, shaping.
Two, destruction of waves.
Three, negation of waves through active transmission of signals, active cancellation.

There are some drawbacks which we have to work around. Shaping affects overall aerodynamics. Destruction requires more onboard power in some cases, like plasma, and increases weight. But negation requires the use of already existing systems on-board.

Masking in background noise doesn't always work anymore. Okay, that's putting it lightly. Successfully using background noise to mask signals has become quite impossible now. It becomes worse when multistatic radars are used, like TRAGEDAC for Rafale. That's why the third method is necessary in order to cancel out specular reflections. Also, we have found out that there is 'no delay' between the stealth system's transmission and the incoming signal.

Analyzing Active Cancellation Stealth | Systems content from Microwaves & RF

Active cancellation stealth is believed to be a smart and adaptive technique that produces a artificial radiation field. Such a field has equal amplitudes and same-frequency, but opposite phase from the target’s scattering field. The enemy radar receiver is always located in the synthetic pattern zero, thereby suppressing the target echo signal received by enemy radar and ultimately achieving stealthy aim.

An ideal active cancellation system will completely remove the need for shaping and destruction.

As for what an F-35 pilot claimed the jet's systems can do, it would be the first method of 'active cancellation', which an 'old crow' like meself considers to be more like EW. An AESA array is required.

Much thanks for the clarification.

 

[Picdelamirand-oil]

There.

For PDF Forumers
What makes this plane "special" is that SPECTRA antenna are Black. All other Rafale have dark green SPECTRA antenna

 

[randomradio]

For PDF Forumers
What makes this plane "special" is that SPECTRA antenna are Black. All other Rafale have dark green SPECTRA antenna

Old Spectra.

Spectra for Electronic Attack. Tail. This reduces edge diffraction from the round edges of the engine along with removing the effects of cavity resonance.

Spectra for EA. Next to canards.

The most secret weapon on Rafale. For distracting enemy pilots.

Free with every Rafale.

 

[Picdelamirand-oil]

Free with every Rafale.

One of Rafale hidden beauties?

 

[gambit]

Thanks. But this is not 'active cancellation'. What you are referring to is destruction of signals. It is a passive cancellation if you will.

Yes, it is.

Absorbers are passive. What I am talking about is electrically manipulating the radar signals after surface penetration.

This is what happens in a completely passive cancellation method...

Essentially, the radar signal's energy is gradually diminished to zero as it travels thru the medium. This method have limited freq range in aviation because of the thickness of the material required for increasing freq ranges.

What I am talking about will be applicable to all practical freq ranges, perhaps even to the meters length freqs.

From what we already know, the Russians already use a combination of RAM/RAS and plasma to achieve the same on PAK FA.

Plasma 'stealth' again ? If what you think of involves the jet creating some sort of a plasma cloud, think again. A more realistic approach is via PLASMA ANTENNAS.

'Plasma Antennas' Could Enable Next-Gen Wi-Fi, Beaming Gigs Per Second Wirelessly | Popular Science

Basically, an array of plasma antennas set to receive in strategic locations on the aircraft's body will absorb most of the seeking radar signals. Every few months here someone brings up the mythical Russian plasma 'stealth' and every yr nothing came out of it.

Masking in background noise doesn't always work anymore.

That is the essence of making a radar low observable body.

I have said it before and will say it again: NOTHING is invisible in radar detection.

The radar sees all. Discrimination is thru data processing, not reception of signals, of which if the discrimination level is low enough, cosmic background radiation (CBR) will be detected. Since every body reflects a small amount of the seeking radar signals, when under radar bombardment, the goal of 'stealth' is to make those reflections as low energy as possible and with the characteristics of background signals as much as possible, forcing the radar receiver to discriminate out these reflected signals. Without that discrimination process, the seeking radar would display everything in the sky, from birds to clouds, and the pilot would be chasing ghosts.

Okay, that's putting it lightly. Successfully using background noise to mask signals has become quite impossible now. It becomes worse when multistatic radars are used, like TRAGEDAC for Rafale. That's why the third method is necessary in order to cancel out specular reflections. Also, we have found out that there is 'no delay' between the stealth system's transmission and the incoming signal.

Ooookayyyyyyy...Maybe there is a misconception of the bi-static concept here.

Rafale News: Rafale developement, TRAGEDAC and LEA

The first one, called TRAGEDAC intends to extend passive localisation capabilities of the Rafale using cooperative technics. The idea is to correlate and synchronise OSF and Spectra data from different aircrafts through link 16 to compute passive tracks more accurately (especially the target range as it is currently the most difficult data to assess using passive sensors only)

Note the highlighted. This is sharing data of PROCESSED radar signals.

The above is a simplified illustration of the basic bi-static radar setup. In this basic configuration, there is no sharing of processed data. At least NOT YET, anyway.

Receivers A and B have what is called the 'bi-static angle' for each of them. The entire setup is called 'multi-static' but the core of the setup is bi-static because of the individual transmitter-receiver pairing.

Each receiver have its own RAW RADAR DATA from the target's reflections. In the above illustration, receiver B will have more reflected signals than A due to the superior bi-static angle. That is the law of physics.

If there are any data sharing between A and B, such sharing will occurs only AFTER each receiver processed its own raw radar data. Receiver A will say something like 'I have target at so-and-so altitude, heading, and speed'. Receiver B will say something similar. And both will analyze each other's responses to see if they are looking at the same target. One set of data is the Doppler component. If both receivers have the target's Doppler component at the same heading, odds are very good that both receivers are looking at the same target. It gets much more complex than this but am sure people get the idea.

For TRAGEDAC, if there is no raw radar data processing by individual receivers, there is no true bi-static configuration. There seems to be a hint of that raw radar data processing, but nothing definitive. Who is the transmitter, a ground station or an airborne one ?

This statement...

...to compute passive tracks more accurately (especially the target range as it is currently the most difficult data to assess using passive sensors only)

...Is very revealing on how the TRAGEDAC idea works.

In order to have target range information -- as in how far is the target away from me -- there must be ACTIVE radar activity FROM ME. In other words, I must be both active and passive, transmitter and receiver.

That statement seems to say that all receivers must be passive, meaning all Rafale fighters in the area must be in passive mode. If a Rafale fighter just happened to receive some sort of target data, it shares it with other Rafale fighters thru Link16. One or more Rafale fighters may not have any radar data at all and must rely on that Link16 information. So again -- if there is no raw radar data processing by the receiver, there is no bi-static configuration.

A truly effective multi-static configuration, that while does not guarantee detection of an F-117 class body but increases the odds of that detection, would have all members be active and data sharing.

Do we have that in the F-22 and F-35 ? Maybe...

 

[Picdelamirand-oil]

Note the highlighted. This is sharing data of PROCESSED radar signals.

No look at the definition you gave:

The first one, called TRAGEDAC intends to extend passive localisation capabilities of the Rafale using cooperative technics. The idea is to correlate and synchronise OSF and Spectra data from different aircrafts through link 16 to compute passive tracks more accurately (especially the target range as it is currently the most difficult data to assess using passive sensors only)

There is no Radar signal to be processed.

For the moment Tragedac is only with passive sensors. With link 16 it is possible to make triangulation, perhaps to put all these data in a Kalman filter to get a localisation and a course and a speed.

But link 16 is not very well fitted with what we want, we want to use a larger base to perform TDOA. For that we certainly will define a link like "MADL", and it's my gess that with this link it becomes possible to develop a multistatic approach, but it would be a second step.

The Rafale hidden beauties and its future

 

[randomradio]

Yes, it is.

Absorbers are passive. What I am talking about is electrically manipulating the radar signals after surface penetration.

This is what happens in a completely passive cancellation method...

Essentially, the radar signal's energy is gradually diminished to zero as it travels thru the medium. This method have limited freq range in aviation because of the thickness of the material required for increasing freq ranges.

What I am talking about will be applicable to all practical freq ranges, perhaps even to the meters length freqs.

I got what you are saying here, I didn't get it before, I assumed you were talking about passive capability. It's a pretty roundabout way of doing it, but most definitely possible. But the problem with this is generation of extra heat. And of course, there's also the question of how well its compatability is against a tactical EMP weapon.

Plasma 'stealth' again ? If what you think of involves the jet creating some sort of a plasma cloud, think again. A more realistic approach is via PLASMA ANTENNAS.

Oh, but it is real. And only certain locations of the aircraft will have this 'inside' the aircraft. As you stated above, the plasma works as a passive absorber. The only difference is if you use regular RAM, or even electrically manipulate the signals, you generate heat, the plasma has the added effect of absorbing that heat. Yes, you will say the heat can be transferred to the fuel, and this is a pretty efficient method, but the rate of absorption of heat and the signals themselves is very high in plasma. It is much more efficient. And the plasma can be generated even when the fuel reserves are low. Another added benefit is its ability to protect critical exposed electronics like antennas from tactical EMP weapons.

One of the known locations for a plasma cloud inside the aircraft is the radome. Whether they will use plasma antennas or some other technique, I do not know, but it is a viable concept.

The only drawback is the energy requirement to make the plasma. It can go into many kilowatts, that's why the new next gen engine is required. But the benefits are many.

I have said it before and will say it again: NOTHING is invisible in radar detection.

The radar sees all. Discrimination is thru data processing, not reception of signals, of which if the discrimination level is low enough, cosmic background radiation (CBR) will be detected. Since every body reflects a small amount of the seeking radar signals, when under radar bombardment, the goal of 'stealth' is to make those reflections as low energy as possible and with the characteristics of background signals as much as possible, forcing the radar receiver to discriminate out these reflected signals. Without that discrimination process, the seeking radar would display everything in the sky, from birds to clouds, and the pilot would be chasing ghosts.

We are in agreement here. But the discrimination process is slowly becoming more and more complex.

With what the Russians are claiming their new radar technology can do, clutter is practically a non-existent issue for such a system. Even less sophisticated radars are facing less problems with discrimination. And a combination of additional sensors and fusion of the data is lowering clutter threshold more and more every year. False alarms are reducing when the radar is coupled with other sensors like IRST. This is not like in the 80s or 90s where major changes happened after many years. Major changes are actually happening in the course of months now. Some of the big changes are the repositioning of the ADC away from the antenna so the radar sees a more detailed image of the aircraft like an insect does through the use of what they are calling 'cells'. This way the entire picture is created by joining data from all those cells into one image. Or even the complete removal of the up-down conversion as a whole, which is quite revolutionary.

Each receiver have its own RAW RADAR DATA from the target's reflections.

This is the case today. Right now, the Rafale uses the regular Link 16 for communication. I don't know if it is actually a part of the Tragedac program, but Spectra will create a separate radio link between groups of Rafale to share radar data in real time. So when a radar of aircraft A transmits, the aircraft also transmits data about the characteristics of the signal within its group.

It's actually much more complex that that because the Rafales are also sharing data from other sensors like the TV camera and the IRST in real time in order to reduce clutter and provide a much higher resolution of the target compared to the information generated from only the radar, like angular resolution from IRST. The TV Camera is very efficient also.

In order to have target range information -- as in how far is the target away from me -- there must be ACTIVE radar activity FROM ME. In other words, I must be both active and passive, transmitter and receiver.

And there seems to be a misunderstanding here. The purpose of Tragedac is to generate track while maintaining radar silence throughout the engagement. So there is no active radar activity. The entire process is passive and range data is calculated through multilateration using TDOA process. Of course for this to work, the target aircraft should be emitting. But that's just half the story. In case the target is not emitting radio waves, then the aircraft's heat signature is taken into account, but at significantly lower ranges.

The accuracy of the Spectra of a single Rafale in passive mode is <1 deg at 200Km. The combination of Rafales will increase accuracy plus add range data. All done passively.

Do we have that in the F-22 and F-35 ? Maybe...

The F-22 cannot have it without a decent datalink. Maybe it will be implemented once the aircraft goes for upgrades in the future. It still uses Link 16 like Rafale. The data bandwidth is too small, information too large.

The F-35 is expected to have it. But the problem is the F-35 is still in development. The last I heard, Lt Gen Bogdan said the F-35 is having difficulties networking with more than 2 aircraft. So there's more work to be done.

No look at the definition you gave:


There is no Radar signal to be processed.

For the moment Tragedac is only with passive sensors. With link 16 it is possible to make triangulation, perhaps to put all these data in a Kalman filter to get a localisation and a course and a speed.

But link 16 is not very well fitted with what we want, we want to use a larger base to perform TDOA. For that we certainly will define a link like "MADL", and it's my gess that with this link it becomes possible to develop a multistatic approach, but it would be a second step.

The Rafale hidden beauties and its future

What is the name of the program for the high capacity datalink? Is it part of TRAGEDAC? INCAS? Or anything else?