F-22's APG-77 vs decoys

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by armedupdate » 16 Aug 2015, 06:30

Since the F-22 lacks a dedicated IRST, how susceptible is the APG-77 to a towed decoy that can simulate an airplane like a MALD? Can it use its SAR to ID a target?


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by eloise » 16 Aug 2015, 07:12

1) MALD is not a towed decoy, towed decoy is something like ALE-55, ALE-70.. etc
2) you cant used SAR mode again enemy's aircraft,
3) AESA radar in general are very resistance to deceptive jamming ( DRFM)
4) in theory, APG-77 may be able to use NCTR mode to distinguished a MALD from an aircraft ( Ex : F-15, F-16.. etc), how effective it is, is questionable


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by armedupdate » 16 Aug 2015, 07:19

Why can't SAR be used air-air?

NCTR how can that distinguish aircraft?


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by eloise » 16 Aug 2015, 07:28

armedupdate wrote:Why can't SAR be used air-air?

A Synthetic Aperture Radar (SAR), or SAR, is a coherent mostly airborne or spaceborne sidelooking radar system which utilizes the flight path of the platform to simulate an extremely large antenna or aperture electronically, and that generates high-resolution remote sensing imagery. Over time, individual transmit/receive cycles (PRT's) are completed with the data from each cycle being stored electronically. The signal processing uses magnitude and phase of the received signals over successive pulses from elements of a synthetic aperture. After a given number of cycles, the stored data is recombined (taking into account the Doppler effects inherent in the different transmitter to target geometry in each succeeding cycle) to create a high resolution image of the terrain being over flown.
Image
The SAR works similar of a phased array, but contrary of a large number of the parallel antenna elements of a phased array, SAR uses one antenna in time-multiplex. The different geometric positions of the antenna elements are result of the moving platform now.
The SAR-processor stores all the radar returned signals, as amplitudes and phases, for the time period T from position A to D. Now it is possible to reconstruct the signal which would have been obtained by an antenna of length v · T, where v is the platform speed. As the line of sight direction changes along the radar platform trajectory, a synthetic aperture is produced by signal processing that has the effect of lengthening the antenna. Making T large makes the „synthetic aperture” large and hence a higher resolution can be achieved.

in short it wont really work again enemy that moving at similar speed with you


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by eloise » 16 Aug 2015, 07:33

ISAR ( inverse SAR) may work again aircraft though


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by armedupdate » 16 Aug 2015, 07:48

Does F-22 have ISAR? (I believe the F-35 does)


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by eloise » 16 Aug 2015, 10:25

armedupdate wrote:Does F-22 have ISAR? (I believe the F-35 does)

if i remember correctly f-22 does have SAR


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by zero-one » 16 Aug 2015, 22:20

I posted a similar question a few months back.

If an enemy air force fills the skies with decoy drones like MALD, that will mimic the radar emissions of multi role fighters.

The F-22 may pick them up as valid BVR targets and waste munitions, not to mention, partially give away their position when they fire at them


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by popcorn » 17 Aug 2015, 00:09

1v1 isn't a realistic scenario and not the way Blue trains and fights. The strength is in the collaboration of sensors-shooters-sharers comprising the Combat Cloud.
"When a fifth-generation fighter meets a fourth-generation fighter—the [latter] dies,”
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by mmm » 17 Aug 2015, 20:02

Well, ISAR can definitely be used as a possible NCTR technique against air target, for starter you could find a good number of essays regarding such application online. Whether that's an operational capability/planned upgrade for F-22 I'll have leave it up to your imagination. APG-77 is a pretty dated AESA(hell APG-81 antenna is even decade old) though, even more so its processor. If nothing else fusing info from ESM should provide a decent ID capability, it does depend on your target to emit in order to positive ID. But in the case of MALD type target it is fairly easy to discriminate even with better known technique like JEM(but then you still don't know if it is a PGM/ALCM). DRFM technique generator like the ALQ-214 on SH combined with towed decoy can be very effective, but that still depend on the ESM to intercept the emitter consistently.

Legacy fighter does have some other ID options, 4th-5th gen datalink capability will probably help in this regard. The irony is that F-22 have historically operate as a isolated 4-ship formation which is rather against its philosophy of info fusion. Had the whole air superiority fleet comprised of only F-22 type(as originally planned) and then updated with MADL compatibility, it would not have been a problem either. Since there's little incentive to seriously modernized F-22, it may be better to just move on to 6th gen ASAP. Too many emerging technology that cannot be foreseen during the days of ATF has come into play anyways.


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by hornetfinn » 18 Aug 2015, 06:28

mmm wrote:APG-77 is a pretty dated AESA(hell APG-81 antenna is even decade old) though, even more so its processor.


I'd like to know what makes AN/APG-77 is dated design in your opinion?

mmm wrote:Since there's little incentive to seriously modernized F-22, it may be better to just move on to 6th gen ASAP. Too many emerging technology that cannot be foreseen during the days of ATF has come into play anyways.


What emerging technologies could not be foreseen in the days of ATF?


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by mmm » 18 Aug 2015, 08:20

hornetfinn wrote:I'd like to know what makes AN/APG-77 is dated design in your opinion?

APG-77 being one of the earliest fighter AESA by definition makes it dated. In terms of technology GaN MMIC and digital beamforming is the way forward.

hornetfinn wrote:What emerging technologies could not be foreseen in the days of ATF?

DEW, cyber, automation are the ones come to my mind first. Also F-22's range is woefully inadequate for pacific theatre IMO.


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by zero-one » 18 Aug 2015, 10:46

popcorn wrote:1v1 isn't a realistic scenario and not the way Blue trains and fights. The strength is in the collaboration of sensors-shooters-sharers comprising the Combat Cloud.


one of the problems of relying too heavily on a combat cloud is that the cloud itself is not always present.

in the opening hours of a coordinated air campaign against a highly advanced enemy. Much of the other assets that make a robust combat cloud won't be there in the first place.

As General hostage pointed out, No Growlers, No AWACs, No Rivet Joint, and no other 4th gen fighter support.
Its just F-22s and F-35s (and probably some B2s) deep passed the IADS lanes.

So you're correct in saying that 1v1 or a particular asset vs a particular asset isn't realistic.

Its not gona be F-22 vs PAK-Fa.

its more likely F-22 vs PAK-FA, Su-27,30,35, Mig-31, A-50, S-400 all data linked together.

But I still say its not a fair fight, they should add more PAK-FAs.

But what if the sky was filled with MALD like drones that emit RF signals, the F-22 may end up shooting cheap drones instead of genuine targets


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by popcorn » 18 Aug 2015, 11:14

The Combat Cloud will be comprised of all sorts of sensor/shooter/sharer assets, covering the EM spectrum. Networked sensor fusion will offer the best means to sort out the wheat from the chaff. F-22 is but one type of node. Expect growing convergence with Army, Navy and USMC fusion-based concepts for even greater battlespace dominance.
"When a fifth-generation fighter meets a fourth-generation fighter—the [latter] dies,”
CSAF Gen. Mark Welsh


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by zero-one » 18 Aug 2015, 11:44

popcorn wrote:The Combat Cloud will be comprised of all sorts of sensor/shooter/sharer assets, covering the EM spectrum. Networked sensor fusion will offer the best means to sort out the wheat from the chaff. F-22 is but one type of node. Expect growing convergence with Army, Navy and USMC fusion-based concepts for even greater battlespace dominance.


Thats only if the other sensor/shooter/sharers will be able or even allowed to get to the battle space where the F-22 operates.
and thats apretty big if
If the enemy was ISIS or some 3rd tier air force then sure.

Try it against China or Russia, and the F-22 will need to rely on it's own sensors and it's own weapons, for the 1st few days of the war.

The F-35 will need to do the same.

The combat cloud will be so much smaller in the 1st moments of a high tech war.


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