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Thread: F-22 - can its ALR-94 ESM detect another F-22's APG-77 LPI radar?

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    F-22 - can its ALR-94 ESM detect another F-22's APG-77 LPI radar?

    Anybody read or heard anything about whether the F-22's ALR-94 ESM can detect another F-22's APG-77 LPI radar at long ranges?

    If an ESM that can defeat the APG-77's LPI feature already exists, what would be tactical implications in a scenario where four non-stealthy fighters with such a capable ESM are pitted against two F-22s?
    Last edited by datafuser; 29th August 2011 at 10:04.

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    Quote Originally Posted by datafuser View Post
    Anybody read or heard anything about whether the F-22's ALR-94 ESM can detect another F-22's APG-77 LPI radar at long ranges?

    If an ESM that can defeat the APG-77's LPI feature already exists, what would be tactical implications in a scenario where four non-stealthy fighters with such a capable ESM are pitted against two F-22s?
    While you present an interesting conundrum for the F-22 fanbois... In reality I'm quite confident that in reality the "LPI" radar is nothing of the sort. "HTI" (Harder To Intercept) might be more applicable - but by no means impossible. There are loads of published papers examining the algorithms of defeating LPI.

    You can be very sure that the various military-centric electronic companies around the world are several years, if not decades ahead of publicly released work.

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    Quote Originally Posted by datafuser View Post
    Anybody read or heard anything about whether the F-22's ALR-94 ESM can detect another F-22's APG-77 LPI radar at long ranges?

    If an ESM that can defeat the APG-77's LPI feature already exists, what would be tactical implications in a scenario where four non-stealthy fighters with such a capable ESM are pitted against two F-22s?
    You are not going to get that kind of answers in a public forum.

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    Quote Originally Posted by Amiga500 View Post
    While you present an interesting conundrum for the F-22 fanbois... In reality I'm quite confident that in reality the "LPI" radar is nothing of the sort. "HTI" (Harder To Intercept) might be more applicable - but by no means impossible. There are loads of published papers examining the algorithms of defeating LPI.

    You can be very sure that the various military-centric electronic companies around the world are several years, if not decades ahead of publicly released work.
    Care to explain the nuance between low probability, and harder to intercept(lower probability)?

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    LPI is an official term and "harder to intercept" is not (and therefore can mean anything).
    "The early bird gets the worm but the second mouse gets the cheese."

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    A F22 can detect another F22 at 10 000 km. Even when grounded. Even when in a (secret) hole. Well known Chuck Norris fact.

    lol

    sorry, it was too tempting

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    Interesting question along the lines of "if you tape some buttered toast to a cats back and drop them which side lands on the ground?"

    As everyone knows that buttered toast always lands buttered side down and cats always land on their feet the answer is simple - they will rotate 10cm off the ground until the cat dies or the butter flies off the toast.

    Source :- http://en.wikipedia.org/wiki/Buttered_cat_paradox


    The real answer should be that the F-22 would be able to detect another F-22 radar as it knows the exact algorithms that make the LPI radar a LPI radar and would predictively look in the right bands.

    Cheers

    PS no toast, cats or tape was harmed in this post..
    John Cook
    Any spelling mistakes/grammatic errors are there purely to annoy. All opinions are mine, not TAFE's however much they beg me for them.

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    Quote Originally Posted by Jwcook View Post
    Interesting question along the lines of "if you tape some buttered toast to a cats back and drop them which side lands on the ground?"

    As everyone knows that buttered toast always lands buttered side down and cats always land on their feet the answer is simple - they will rotate 10cm off the ground until the cat dies or the butter flies off the toast.

    Source :- http://en.wikipedia.org/wiki/Buttered_cat_paradox


    The real answer should be that the F-22 would be able to detect another F-22 radar as it knows the exact algorithms that make the LPI radar a LPI radar and would predictively look in the right bands.

    Cheers

    PS no toast, cats or tape was harmed in this post..
    OK, let's suppose the Su-35S has an ESM that can detect the F-22's APG-77 radar at long ranges. What would be tactical implications?

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    Quote Originally Posted by datafuser View Post
    OK, let's suppose the Su-35S has an ESM that can detect the F-22's APG-77 radar at long ranges. What would be tactical implications?
    The Su-35 could engage using some form of weapon that doesn't involve it using its own radar? Or run away should that not be possible? Or jam the F-22's radar and attempt to engage? Who knows..

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    All this talk of radars and ECM, and move - counter move, got me thinking that the smart play (and getting smarter and smarter by the day) is to take a page from the submarine community and "go passive". IRST systems are the way to go for stealthy aircraft going forward IMHO providing that they can do a good enough job to replace radar emissions in most air combat scenarios.

    How close are IRST systems, like PIRATE system on Typhoon for example, to supplant the need to emit tons of radiation that radars usually do yet still get the job done?
    "It was a magnificent display of trained and disciplined valour, and its assault only failed of success because dead men can advance no further."

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    Modern IRST can see an approaching fighter from about 30-50nm away. This is well short of what the latest radar/AAMs can do. The IRST has a LONG way to go before it supplants radar as the primary sensor for A2A engagements.
    "The early bird gets the worm but the second mouse gets the cheese."

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    Depends on weather, SBIRS can detect fighters on a/b from space,
    donno how high up they are but i'm confident it's more than 50 nm.
    The catch is weather, they are pretty useless in snow/rain.
    the missile will require about five times the G capability of the target to complete a successful intercept.
    -Robert L Shaw

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    Quote Originally Posted by wrightwing View Post
    Care to explain the nuance between low probability, and harder to intercept(lower probability)?
    Low probability means you probably won't intercept (at useful ranges).

    Harder means you will (at useful ranges), you'll just have to spend more time and money on your RWR suite to do so.


    Simple really.

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    Quote Originally Posted by SpudmanWP View Post
    Modern IRST can see an approaching fighter from about 30-50nm away. This is well short of what the latest radar/AAMs can do. The IRST has a LONG way to go before it supplants radar as the primary sensor for A2A engagements.
    IMO; the primary sensors for future A2A engagements will have to be either offboard or passive.


    Active on-board is gonna be like a submarine running around with active sonar on full blast.

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    I hope this isn't a stupid question, but is it possible for a small, short-range IR missile to shoot down another AAM such as the AIM-120?

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    Quote Originally Posted by Jwcook View Post

    The real answer should be that the F-22 would be able to detect another F-22 radar as it knows the exact algorithms that make the LPI radar a LPI radar and would predictively look in the right bands.

    Cheers

    PS no toast, cats or tape was harmed in this post..
    In that case the F-22 (1) would be capable of getting a lock and shoot down the F-22 (2) using a flying buttered cat...

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    Quote Originally Posted by datafuser View Post
    Anybody read or heard anything about whether the F-22's ALR-94 ESM can detect another F-22's APG-77 LPI radar at long ranges?

    If an ESM that can defeat the APG-77's LPI feature already exists, what would be tactical implications in a scenario where four non-stealthy fighters with such a capable ESM are pitted against two F-22s?

    Maybe a nice academic question, but in the real world: Who cares?

    Low tech enemies will learn to hide for the F-22, will attack it with human eye and ears guided low tech weapons, and every once in a while will have a small success.

    Not able to do some serious ground attack it will ensure air supremacy while the real war will take place on other fronts.

    A cold war cartoon showed two soviet generals talking to each other during a victory parade under the Eiffel tower with one of them saying: by the way, who won the air superiority battle at the end?".

    The soviet block was defeated by economical means, not military, and it appears that now the US is being defeated by some afghan militants using the same technique.

    187 F-22 seem barely enough to protect US borders, and seem completely insufficient to make a real difference during a full blown war with an equally equiped enemy.

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    Quote Originally Posted by drabslab View Post
    Maybe a nice academic question, but in the real world: Who cares?

    Low tech enemies will learn to hide for the F-22, will attack it with human eye and ears guided low tech weapons, and every once in a while will have a small success.

    Not able to do some serious ground attack it will ensure air supremacy while the real war will take place on other fronts.

    A cold war cartoon showed two soviet generals talking to each other during a victory parade under the Eiffel tower with one of them saying: by the way, who won the air superiority battle at the end?".

    The soviet block was defeated by economical means, not military, and it appears that now the US is being defeated by some afghan militants using the same technique.

    187 F-22 seem barely enough to protect US borders, and seem completely insufficient to make a real difference during a full blown war with an equally equiped enemy.
    As this post goes to show, one man's defeat is another man's victory (ref afghan campaign), so it would be too hard to interpret the results anyway.

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    Quote Originally Posted by flanker30 View Post
    I hope this isn't a stupid question, but is it possible for a small, short-range IR missile to shoot down another AAM such as the AIM-120?
    Yes, IRIS-T is advertised with that capability
    the missile will require about five times the G capability of the target to complete a successful intercept.
    -Robert L Shaw

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    Quote Originally Posted by drabslab View Post
    187 F-22 seem barely enough to protect US borders, and seem completely insufficient to make a real difference during a full blown war with an equally equiped enemy.
    Two questions:
    Why anyone in his right mind would use the Raptor to "protect US borders" with thousands of Vipers in the USAF inventory?
    An "equally" equiped enemy? Who´s "that"?
    At least for the next decade, something like four sqn´s of F-22 would probably be more than enough to tilt an Air Battle over any potential clash point with any existing "near peer" threat, that includes China.

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    Quote Originally Posted by SpudmanWP View Post
    Modern IRST can see an approaching fighter from about 30-50nm away. This is well short of what the latest radar/AAMs can do. The IRST has a LONG way to go before it supplants radar as the primary sensor for A2A engagements.
    What about ESM? ESM only needs to pick up emissions, while radar has to send out emissions and RECEIVE them back. If a radar can see a target at 100 NM, an ESM may "hear" that radar over 200 NM away.

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    Quote Originally Posted by Sintra View Post
    Two questions:
    Why anyone in his right mind would use the Raptor to "protect US borders" with thousands of Vipers in the USAF inventory?
    An "equally" equiped enemy? Who´s "that"?
    At least for the next decade, something like four sqn´s of F-22 would probably be more than enough to tilt an Air Battle over any potential clash point with any existing "near peer" threat, that includes China.
    Equally equipped enemy is anyone who owns sufficient assets to attack the forward bases where F-22s would be deployed. It would be plain stupid to concentrate effort on targeting the F-22s while they are flying whern you can comfortably blow them to pieces while on the ground.

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    Quote Originally Posted by Amiga500 View Post
    IMO; the primary sensors for future A2A engagements will have to be either offboard or passive.


    Active on-board is gonna be like a submarine running around with active sonar on full blast.
    A poster at another forum says "The LO characteristics of the F-22s act against the seekers of the weapons launched by the OPFOR as much as they do against the search sensors and the smaller and lower power sensors on the missiles will have a much more difficult time achieving lock on their own."

    If true, future BVR missiles should also be infra-red imaging ones or something else.

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    Quote Originally Posted by MSphere View Post
    Equally equipped enemy is anyone who owns sufficient assets to attack the forward bases where F-22s would be deployed. It would be plain stupid to concentrate effort on targeting the F-22s while they are flying whern you can comfortably blow them to pieces while on the ground.
    Yes it's always better to destroy enemy air power on the ground as the Israelis did in 1967.

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    LPI is used by a large number of radars

    Check out this and scroll down to see other examples
    http://www.scribd.com/doc/40385576/D...ntercept-Radar
    the missile will require about five times the G capability of the target to complete a successful intercept.
    -Robert L Shaw

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    Quote Originally Posted by obligatory View Post
    Yes, IRIS-T is advertised with that capability
    So an aircraft with a missile warning system and IRIS-T is immune to attack from medium/long-range air-to-air missiles, such as the AIM-120 (assuming of course that the detection/warning system and the IRIS-T are functioning correctly)?

    If so, does that mean that the F-22 cannot shoot down such an aircraft at long range, regardless of whether or not the other aircraft can detect it or not?

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    Anybody read or heard anything about whether the F-22's ALR-94 ESM can detect another F-22's APG-77 LPI radar at long ranges?
    It's simple, till the russians (or whatever else) did not develop a real LPI mode radar the F-22s LPI ones will be absolutely undetectable by anyone, others F22s included.
    When russians (or whatever else) will boast about their absolutely good LPI mode radar then ... no jokes, LPI to whom?

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    Quote Originally Posted by datafuser View Post
    If true, future BVR missiles should also be infra-red imaging ones or something else.
    Like the MICA IR?

    Or what the eventual R-27ET replacement will be?

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    Quote Originally Posted by datafuser View Post
    What about ESM? ESM only needs to pick up emissions, while radar has to send out emissions and RECEIVE them back. If a radar can see a target at 100 NM, an ESM may "hear" that radar over 200 NM away.
    Not only does the ESM have to "receive" the radar signal, but also:
    1. Recognize it as such.
    2. Intercept enough of it in order to get a bearing to the F-22.
    3. Get even more of it in order to get a 3D positional fix.
    4. Be painted long enough in order to get a vector to the F-22 in order to use your own AAMs against it.

    A break in any of the above and you will not be able to prosecute a missile shot against the F-22. There is also the issue of networking to deal with. While you may "intercept" the radar from the F-22 going active 150nm away, you will never hear from the F-22 that is only 50nm away that got updated with your position.
    "The early bird gets the worm but the second mouse gets the cheese."

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    Interesting question - because when you think about it, LPI is fundamental to air-to-air stealth.

    We don't know that much about LPI techniques, although the paper cited above is interesting.

    We don't know how much today's achievable LPI compares with the hopes and plans of 1985.

    We do know, however, that fighters have become more difficult radar targets since 1985 - which is apt to make LPI more difficult insofar as it implies using the minimum energy on target.

    Targets have become more difficult because of:
    - Frontal sector X-band RCS reduction
    - Much improved passive EW with greater bearing accuracy
    - Cooperative passive tracking that can provide very rapid location
    - More directional and more responsive active EW enabled by phased arrays and DRFM

    Did the standards for LPI established in the ATF program take account of all those developments?

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