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Rafale 2018 Thread: Europe's best Eurocanard

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  • TomcatViP
    Rank 5 Registered User
    • Nov 2011
    • 6001

    So it is not true to say that the Rafale doesn't have sensor fusion. It does - every bit as much as the Raptor or Typhoon.
    Nobody said that Rafale never had a bit of fusion. Some only said Rafale history shows that most of the intended fusion capabilities where effectively mooted by:
    - 1st the lack of broad spectrum stealth
    - 2nd the lack of a coherent planing in system upgrade that led all sensor (apart from from the SPECTRA suite) to be removed/replaced.

    The little loop on the LM doc shows exactly that. There are no IR or Radar feed in teh fusion process. That's what some wrote. And that is of utmost importance to assess what the Rafale can do or not.

    Comment

    • halloweene
      Rank 5 Registered User
      • Jan 2012
      • 4314

      2nd the lack of a coherent planing in system upgrade that led all sensor (apart from from the SPECTRA suite) to be removed/replaced.
      Say like... EOTS, EODAS etc.? Hilarious. The little loop on the LM doc is hat it is a little loop on a ppt. And a fairly hilarious one btw. Sensor fusion may itself change the radar mode e.g.?

      LM has NO idea on how sensor fusion is performed on Rafale. But what they show for "4th gen" is what happens for F-18.

      Comment

      • XB-70
        Rank 4 Registered User
        • May 2018
        • 276

        The little loop on the LM doc shows exactly that. There are no IR or Radar feed in teh fusion process.
        It's a closed loop and so it actually does show that. The Lockmart slide is just a generalization of previous sensor fusion schemes anyways.

        Here's a link with some detailed info on the Rafale's microelectronics hardware. http://adsabs.harvard.edu/full/1996ESASP.375..111N

        Basic capabilities:
        2 SPARC processors @ 33MHz
        STANAG 3910 avionics standard (just like Typhoon)
        Max bus bandwidth - 20Mbit/s
        Coded in Ada

        It's built for devices to talk together - they simply have to comply with STANAG 3910 (or MIL-STD-1553). I really don't know what it is that you read that's got you thinking otherwise.

        2nd the lack of a coherent planing in system upgrade that led all sensor (apart from from the SPECTRA suite) to be removed/replaced.
        STANAG 3910 is plug and play. You can replace components on that bus just like how you can swap out devices plugged in with Ethernet or USB. You just have to obey the transfer protocol and physical layer requirements. The French would have had to have been grossly incompetent to mess that up. What did you read that makes you think this?

        Comment

        • XB-70
          Rank 4 Registered User
          • May 2018
          • 276

          I thought most modern jamming systems did that.
          Nope. Most jammers are used for denying/degrading an adversary's use of parts of the RF spectrum over large areas. So they are geared for transmitting at high power levels over a wide frequency band (or a rapidly shifting one). They also attempt to create false targets through the exploitation of vulnerable sidelobes. They try to cover and shield several assets over a wide area. Dassault's "active stealth" is an attempt to shield just the fighter.

          Comment

          • TomcatViP
            Rank 5 Registered User
            • Nov 2011
            • 6001

            You can replace components on that bus just like how you can swap out devices plugged in with Ethernet or USB.
            First laughter of 2019!

            Comment

            • OPIT
              Rank 5 Registered User
              • Aug 2005
              • 898

              Originally posted by TomcatViP
              First laughter of 2019!
              You'll never grow up...

              Comment

              • halloweene
                Rank 5 Registered User
                • Jan 2012
                • 4314

                Basic capabilities:
                2 SPARC processors @ 33MHz
                STANAG 3910 avionics standard (just like Typhoon)
                Max bus bandwidth - 20Mbit/s
                Coded in Ada

                Hello. Albeit this document is about Rafale F1 (a stop gap Rafale so as to replace Crusaders) is interesting, it is outdated.

                http://www.portail-aviation.com/blog...ns-levolution/

                subsystems are virtualized...

                Comment

                • eagle1
                  Rank 5 Registered User
                  • Feb 2011
                  • 1124

                  Unlike XB-70 said on the previous page rafale sensor fusion is actually processed the same way the F35 does. The server that fuses primary data on the rafale is called the MDPU.

                  That's exactly why Dassault insists that rafale multi sensor fusion is not merely a corelation of tracks like described on LM PPt first slide.

                  Comment

                  • TomcatViP
                    Rank 5 Registered User
                    • Nov 2011
                    • 6001

                    Govt of India [...] makes 25 per cent payment to French govt


                    [...] The Narendra Modi government has taken the next step by issuing 25 per cent of the payment due to the French government in the over Rs 59,000 crore deal. This was revealed in a report by news agency ANIciting top Air Force sources. India is procuring 36 Rafale fighter jets from Frances Dassault Aviation in flyaway condition in a government-to-government deal.

                    Sources told the news agency the plane delivery schedule was on track and the Indian Air Force is expected to get the first aircraft in September 2019. The jets would be put to extensive testing by Indian pilots to evaluate the India-specific enhancements.
                    [...]
                    "More than 25 per cent of the payments have been made to the French government for the deal as part of the contractual terms and conditions of the project. The amount of the payment is being paid to the French government as the contract is government to government,"
                    Last edited by TomcatViP; 1st January 2019, 15:45.

                    Comment

                    • St. John
                      Rank 4 Registered User
                      • Jan 2018
                      • 568

                      XB-70 - That seems at odds with the fact that they use DRFM (Digital Radio Frequency Memory) to copy the threat transmission first. That's clearly about way more than just denying parts of the spectrum or exploiting side lobes. If you've copied the strength and frequency of the transmission, there's nothing to stop you just playing it back 180deg out of phase surely.

                      Comment

                      • XB-70
                        Rank 4 Registered User
                        • May 2018
                        • 276

                        Thanks for the link, halloweene! OK, it looks like the processors have been (certainly) upgraded to 733MHz PowerPCs, and it suggests that they are currently 1GHz+. But nothing was mentioned about replacing that STANAG 3910 bus. I've heard the F-35 is also PowerPC based (an architecture that is known to be particularly environmentally hardened and so has been used on Mars rovers and such) but I've never found anything definite. The increase in processing power would suggest they replaced the STANAG 3910 bus but it isn't certain. Replacing it would be a far greater task than swapping out a device (processor or sensor) on that bus.

                        St. John - You've got to do that anyways to be effective. Although you want to degrade your adversary's use of the spectrum while jamming you do not want to degrade your own use of it. So you have to know a bit about your adversary's capabilities. The X-band, for instance, is defined as 8-12GHz. An X-band radar though only outputs a 100MHz or so pulse which sweeps/hops across that 8-12GHz over a period of time (microseconds). So you can jam by outputting broadband noise across 8-12 GHz which will do very well at keeping your adversary from using the X-band but it also does just as well at keeping your own forces from using it. Or you can try to follow your adversary's transmitter, and just corrupt what it is scanning at. (This will still cause some collateral damage for your own forces, but far, far less.)

                        The differences with Dassault's active cancellation and traditional jamming is 1) precision. For jamming, you really only want to follow frequency very well. Phase is not so important, and power you want to be high. For active cancellation, you do want to be exactly 180 degrees out of phase and you want your power to be precisely equal to the power of the reflected wave from your aircraft. Now, if a particular jamming system has the precision for each property then it could try to use active cancellation. But 2) the mission requirements come into play. A USN Growler is often the support aircraft on strike missions. It is just there to degrade hostile's use of the spectrum with EW so that other assets can deploy weapons safely. If you need to cover for someone else then you aren't going to try active cancellation. That only works for covering your own tail. Usually jamming assets are there to cover others!

                        Comment

                        • garryA
                          Rank 5 Registered User
                          • Dec 2015
                          • 1120

                          Generations of sensor fusionClick image for larger version

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                          Comment

                          • TomcatViP
                            Rank 5 Registered User
                            • Nov 2011
                            • 6001

                            Thank you GarryA. Great doc. Any attentive reading should help to temper down some of the verbal arrogance here.
                            Last edited by TomcatViP; 2nd January 2019, 12:31.

                            Comment

                            • TomcatViP
                              Rank 5 Registered User
                              • Nov 2011
                              • 6001

                              Usually jamming assets are there to cover others!
                              Your question about the difference (if any) b/w the vaunted active cancellation and Jamming implied self-jamming. Hence I don't see why we have to deal with EA aircraft like the Growler.

                              Comment

                              • halloweene
                                Rank 5 Registered User
                                • Jan 2012
                                • 4314

                                Any attentive reading should help to temper down some of the verbal arrogance here.
                                Wll you? God gracious.Gonna be a nice year!

                                Comment

                                • XB-70
                                  Rank 4 Registered User
                                  • May 2018
                                  • 276

                                  TomcatViP - What do you mean by self-jamming? You would never want to degrade your own sensory capability. Dassault's technology is a form of electronic warfare, yes, but it is not jamming. Jamming is about degrading SNR with broad area noise. That's been the case ever since the RAF first started dropping chaff over Germany back in WWII - resulting in the valid radar signals from their bombers being lost and hidden in the noise and so the German guns couldn't locate them. Active cancellation takes a different and more precise approach. The addition of two sinusoidal signals of the same frequency and amplitude, but 180 degrees out of phase is always zero - for all time. So, when the Rafale uses it, the sum of the enemy's reflected radar signal and its own active cancellation signal is zero - as if there were no radar return and the aircraft had a RCS of zero. (Now there is always some time jitter/phase noise in both signals so it will never be exactly zero - but close.) It only covers yourself. EW platforms traditionally cover others and so do not use this approach. But any EW platform with the correct precision in amplitude and phase (and also had a comprehensive RCS database to work with) could do it. It's not magic.

                                  Comment

                                  • garryA
                                    Rank 5 Registered User
                                    • Dec 2015
                                    • 1120

                                    XB-70 Tomcat is referring to self protection jamming (normally deceptive jamming) which is quite different from support jamming (normally noise jamming).
                                    it is not correct that all form of jamming use board area noise, there are several kind of jamming that need precise phase/frequency characteristic such as cross eye jamming,
                                    Click image for larger version

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                                    cross polarization jamming. Common deceptive jamming like range gate pull off or velocity gate pull off or inverse conscan jamming also require you to know the operating frequency of target radars.
                                    Moreover, you can't make aircraft RCS become zero, not even with active cancellation, because there will be a delay from when adversary signal hit your airframe and when the jammer can produce a 180 degree out of phase wave, in other words, there is a part of the pulse that you can't cancel.
                                    Last edited by garryA; 3rd January 2019, 04:50.

                                    Comment

                                    • halloweene
                                      Rank 5 Registered User
                                      • Jan 2012
                                      • 4314

                                      I think noone said that Rafale RCS was downed to zero. There will alays be a small delay between signal reception, DRFM, applying functions, reemitting. Front end pulse use from ennemy radar can partly mitigate that, but there will always be a degradation, and that is the idea (break the kill chain long enough so as to invalidate tactical situation).
                                      Oh and BAT120 test was succesful (nrelated)

                                      https://twitter.com/ThalesDefence/st...75368870756352
                                      Last edited by halloweene; 4th January 2019, 14:07.

                                      Comment

                                      • XB-70
                                        Rank 4 Registered User
                                        • May 2018
                                        • 276

                                        Tomcat is referring to self protection jamming (normally deceptive jamming) which is quite different from support jamming (normally noise jamming).
                                        garryA - Well, I looked into several of these and they aren't really different at all.

                                        They even say as much. "Any practical jammer must radiate sufficient power to over-ride, or pre-dominate in its effect over, the natural target skin echo." So, these methods still use the same principle where a larger 'noise' signal outweighs and masks the true signal (which is still there). That's why they call it jamming. (It does appear to be more localized over geographical area but no other difference.)

                                        http://citeseerx.ist.psu.edu/viewdoc...=rep1&type=pdf
                                        https://apps.dtic.mil/dtic/tr/fulltext/u2/336943.pdf

                                        ...because there will be a delay from when adversary signal hit your airframe and when the jammer can produce a 180 degree out of phase wave, in other words, there is a part of the pulse that you can't cancel.
                                        Yes and no. Sure, it ain't like US stealth technology. The technology they have appears to require the characteristics of the 'threat' radar to be known to the system (and it can probably only work against one or two at a time). It also depends on how well they have characterized the rafale from all aspects with all loadout configurations (and certainly that will sometimes be just a rough estimate). But the time to reproduce shouldn't usually be critical. When it first detects a scan it will need some time to first analyze the threat radar before it can send out a mimicked signal 180 degrees out of phase. But there are two points you need to consider. 1) The power from a radar signal attenuates under a 1/(d^2) characteristic - both ways. So the Rafale can capture a signal at a threat power level before that threat can capture the (even further attenuated) reflected signal. Usually. 2) Humans need a lot of time (in comparison with electronics) to capture and process information. A cockpit display refreshes at say 60fps (or 1 frame every 0.0167 seconds). If it takes the system 0.25-.03 seconds to capture pulses and process the info then it still might only show up on one frame. That's not enough for a person to notice; it would be there and gone in the blink of an eye. And that's assuming the radar's processing doesn't write it off as a noise spike and discard the info.

                                        Comment

                                        • garryA
                                          Rank 5 Registered User
                                          • Dec 2015
                                          • 1120

                                          XB-70
                                          Well, I looked into several of these and they aren't really different at all.
                                          They even say as much. "Any practical jammer must radiate sufficient power to over-ride, or pre-dominate in its effect over, the natural target skin echo." So, these methods still use the same principle where a larger 'noise' signal outweighs and masks the true signal (which is still there). That's why they call it jamming. (It does appear to be more localized over geographical area but no other difference.)
                                          All form of jamming ("active cancellation" included), need a certain level of J/S ratio to be effective, in that sense the jammer need to radiate at sufficient power to be effective.
                                          Different kind of jamming will have different requirement for this J/S level.
                                          Click image for larger version  Name:	aesa-radar2.png Views:	1 Size:	21.5 KB ID:	3845501
                                          Deceptive jamming is not the same as noise jamming in the sense that they attempt to inject false information that can be interpreted as real return instead of only simply blank out the real return like noise jamming. It kinda similar to the situation when you follow a person, he can either try to blind you completely with a powerful flash light, or he can (by some unique device) project to your eye, a fake image of him walking in different direction, different speed, and to do that, deceptive (or self protection jammer need precise information about threat radar.
                                          Click image for larger version  Name:	cross eye.PNG Views:	1 Size:	54.8 KB ID:	3845502Click image for larger version  Name:	cross polarized.PNG Views:	1 Size:	82.6 KB ID:	3845503Click image for larger version  Name:	RGPO.PNG Views:	1 Size:	157.9 KB ID:	3845504
                                          This is a very good video on the subject,
                                          https://www.youtube.com/watch?v=d5T1vPmA-l4

                                          When it first detects a scan it will need some time to first analyze the threat radar before it can send out a mimicked signal 180 degrees out of phase. But there are two points you need to consider. 1) The power from a radar signal attenuates under a 1/(d^2) characteristic - both ways. So the Rafale can capture a signal at a threat power level before that threat can capture the (even further attenuated) reflected signal. Usually. 2) Humans need a lot of time (in comparison with electronics) to capture and process information. A cockpit display refreshes at say 60fps (or 1 frame every 0.0167 seconds). If it takes the system 0.25-.03 seconds to capture pulses and process the info then it still might only show up on one frame. That's not enough for a person to notice; it would be there and gone in the blink of an eye. And that's assuming the radar's processing doesn't write it off as a noise spike and discard the info.
                                          1) That correct, but while the signal the threat radar received will be weaker, the pulse length is the same.
                                          2) That assumption is only correct, if the radar use a constant frequency/ PRF rate, because after the initial delay, your jammer can adjust to completely silent enemy radar (since you now know exact frequency and phase of reflected signal in the future). However, if adversary radar constantly frequency hopping and jitters their PRF randomly, then there will be a part of each individual pulse (or sub-pulse in case of pulse compression) that you can't "cancel" because your signal need to overlap with radar return to cause destructive interference. For example,in photo below, there is a small part of f1, f2, f3 and f4 that can't be "canceled", inother words, the "flash" will show up multiple times
                                          Click image for larger version  Name:	compress pulse.png Views:	1 Size:	59.8 KB ID:	3845505
                                          You might think, this part is small and negligible but leading-edge-tracking (aka taking measurements not according to where the center of the return signal is but rather at the leading edge .All RGPO/RGPI cover pulse jamming tends to lag the targets returns by some increment of time) is actually a very common ECCM method

                                          Last edited by garryA; 4th January 2019, 08:39.

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