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Rafale deal signed

Discussion in 'Indian Air Force' started by PARIKRAMA, Sep 23, 2016.

  1. Metrology

    Metrology FULL MEMBER

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    Point is, the Rafale will be detected by LPI, hence the RCS-claims are at best very situational. Being detected, even without targeting info, means you have lost a significant part of the advantage.

    Problem is that active cancellation probably requires a predictive radar. Without it you would have to detect, analyse and transmitting the inverted pulse within a fraction of the pulse duration, which seems to be in the range a microsecond. That leaves you with a maximum cycledepth in the range of tens to hundreds clock cycles depending on hardware and how much you need to cover. In that time you have to detect and analyze the incoming signal and produce the inverse pulse. The lower end I think is downright impossible and I'm rather sceptical to the feasibility of the higher end. You also have to detect the end of the signal and stop transmitting, or you will cause the opposite effect. That means you have have to be able to transmit and listen at the same time. Not sure that that is possible. Also, if the radar hops in frequency, it requires listening ability and again cuts your available time to do the detection and analyzing in fractions. I don't see that happening.

    I have never questioned that it's theoretically possible, what I questioned was the practical possibility against a modern radar.
     
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  2. randomradio

    randomradio Colonel REGISTERED

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    This applies to all aircraft when faced against sufficiently advanced radars, the F-22 and F-35 as well.

    It's unclear how it's accomplished exactly, so no point speculating. All we know is it exists and it reduces RCS dramatically. Picdel says the cancellation signal is transmitted from the very first pulse itself.

    As for detecting the end of the signal and stop transmitting, that's easy.
     
  3. Picdelamirand-oil

    Picdelamirand-oil Lt. Colonel MILITARY STRATEGIST

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    @Sancho What do you think of these Facts (I can give you the name by MP if you want)
     
  4. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    That is why Rafale relies on a very strong threat library. If a signal is not in its memory, it can't jam it straight away.
     
  5. randomradio

    randomradio Colonel REGISTERED

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    From what Picdel has said, Rafale doesn't have to rely on a threat library alone.
     
  6. Picdelamirand-oil

    Picdelamirand-oil Lt. Colonel MILITARY STRATEGIST

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    Rafale caught in the meanders of Indian politics

    https://translate.google.fr/transla...-de-la-politique-indienne_1613189&prev=search
     
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  7. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    yes, as it can record it on the spot and create a cancellation signal. but in case of lpI radar, the signal is not continuous nor repetative.
     
  8. randomradio

    randomradio Colonel REGISTERED

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    Agreed, but this is in a very specific scenario.

    Normally, you will have multiple radars and sensors watching the sky, so something like the F-22 will still get picked up by some other radar or other sensor, inform the Rafale about the presence of the F-22, and any signal coming from the direction of the F-22 will get canceled since Spectra is capable of highly accurate localization.

    The Rafale's lack of IWB and shaping is a drawback, but it still holds far too many survivability cards against current levels of stealth. So even if the Rafale is detected using LPI, the Rafale's Spectra may prevent a radar lock. If that fails, the Spectra can prevent missile lock. So post detection, the Rafale still has multiple alternate stealth options, the F-22 does not. Detection is simply a part of the kill chain.
     
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  9. Picdelamirand-oil

    Picdelamirand-oil Lt. Colonel MILITARY STRATEGIST

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    Doesn't matter it's the signal itself that we modify and send back, it takes no time, just the time to change the phase: the modification to apply is prepared but we apply it to the signal itself to gain time.
     
  10. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    Bro, I am sure its not somekind of cocktail shaker where you have ice and other ingredients ready and just need to add the main drink to shake and serve.
     
  11. Picdelamirand-oil

    Picdelamirand-oil Lt. Colonel MILITARY STRATEGIST

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    Preparation can be done independant of the signal because it depend of the model of own plane (known by spectra), position of the plane, course of the plane, position of the ennemy radar. All these parameters evolve slowly compare to the time scale of the signal...
     
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  12. randomradio

    randomradio Colonel REGISTERED

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    Do you even sample the signal?
     
  13. Picdelamirand-oil

    Picdelamirand-oil Lt. Colonel MILITARY STRATEGIST

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    It can be done in parallel for the library. The library in SPECTRA is primarily used to identify threats, not real-time processing.
     
  14. vstol jockey

    vstol jockey Colonel MILITARY STRATEGIST

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    Spectra can't something like a mirror. it will have a time gap between the signal falling on it and the signal sent out.
     
  15. randomradio

    randomradio Colonel REGISTERED

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    No, I mean doesn't AC require sampling?
     

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