F-22's APG-77 vs decoys

Unread postPosted: 16 Aug 2015, 06:30
by armedupdate
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?

Re: F-22's APG-77 vs decoys

Unread postPosted: 16 Aug 2015, 07:12
by eloise
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

Re: F-22's APG-77 vs decoys

Unread postPosted: 16 Aug 2015, 07:19
by armedupdate
Why can't SAR be used air-air?

NCTR how can that distinguish aircraft?

Re: F-22's APG-77 vs decoys

Unread postPosted: 16 Aug 2015, 07:28
by eloise
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

Re: F-22's APG-77 vs decoys

Unread postPosted: 16 Aug 2015, 07:33
by eloise
ISAR ( inverse SAR) may work again aircraft though

Re: F-22's APG-77 vs decoys

Unread postPosted: 16 Aug 2015, 07:48
by armedupdate
Does F-22 have ISAR? (I believe the F-35 does)

Re: F-22's APG-77 vs decoys

Unread postPosted: 16 Aug 2015, 10:25
by eloise
armedupdate wrote:Does F-22 have ISAR? (I believe the F-35 does)

if i remember correctly f-22 does have SAR

Re: F-22's APG-77 vs decoys

Unread postPosted: 16 Aug 2015, 22:20
by zero-one
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

Re: F-22's APG-77 vs decoys

Unread postPosted: 17 Aug 2015, 00:09
by popcorn
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.

Re: F-22's APG-77 vs decoys

Unread postPosted: 17 Aug 2015, 20:02
by mmm
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.

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 06:28
by hornetfinn
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?

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 08:20
by mmm
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.

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 10:46
by zero-one
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

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 11:14
by popcorn
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.

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 11:44
by zero-one
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.

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 12:02
by popcorn
I do not presume to know how war planners would conduct a highly orchestrated air campaign. We think we know a lot but much is unknown about the real capabilities of various platforms like the F-22. Let alone other components of the US force structure. Same unknowns for the tactics that will be employed, given that many CONOPS are still being formulated and in flux. I do think your scenarios extremely simplistic and given what we don't know, highly speculative at best.

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 13:10
by hornetfinn
zero-one wrote: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.


I don't know what realistic situation could result in Russia or China having all those assets in place and all of them datalinked together and USA not being able to bring similar assets to the party? Russia could have all of those protecting deep inside Russia, but it'd take a lot of effort from Russia to take them somewhere else. Same with China and I doubt anybody is going to risk full nuclear war against either one.

zero-one wrote: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


I don't know how MALD like drones could be used inside own territory and not hamper other defenses a lot. Realistic drones are also quite expensive and launching salvos of them would require a lot of drones.

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 14:05
by zero-one
popcorn wrote:I do not presume to know how war planners would conduct a highly orchestrated air campaign. We think we know a lot but much is unknown about the real capabilities of various platforms like the F-22. Let alone other components of the US force structure. Same unknowns for the tactics that will be employed, given that many CONOPS are still being formulated and in flux. I do think your scenarios extremely simplistic and given what we don't know, highly speculative at best.


We don't know and likely we never will, but lets work with what we do know. chances are, we are way off, but that will have to do.

http://breakingdefense.com/2014/06/gen- ... -starts/3/
In here, Gen Mike Hostage discusses how he expects to use American technological superiority in a future strike behind (A2\AD)

Gen Mike Hostage wrote:But in the first moments of a conflict I’m not sending Growlers or F-16s or F-15Es anywhere close to that environment, so now I’m going to have to put my fifth gen in there


So in the first few moments of WW3, its gona be a pure 5th gen fleet.

It won't be outlandish to assume that they are expected to fight alone. Thats why these things are crammed with so many sensors and so much capability, so that they won't need to rely on other sensors/shooters and sharers

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 15:54
by popcorn
The Combat Cloud could be comprised of F-22, F-35 and Legacy jets. If needed, B-2 could operate from day one. RQ-180 as well. In the future, LRSB. All adding their unique capabilities to the Cloud. Other non-AF systems may also contribute to the effectiveness of the Combat Cloud eg. AEGIS /SM-6, AN-TPY2/THAAD, etc. What about space-based sensors? This is just my layman's appreciation, it's a safe bet there's a lot more not in the public domain.

Gen. Hostage was making a specific point re unsuitabiliy of Growler jamming, it does not follow that it will be a 5Genshow exclusively at the start. Note the priority in developing 5Gen/4Gen datalink capability to enhance interoperability between the 2 generations.



http://www.sldinfo.com/shaping-the-way- ... he-future/

This combat cloud would be enabled by fifth generation aircraft and include the deployment of F-22s, a substantial number of F-35s and the ability to link to legacy aircraft. This capability would then define the approach to any systems added thereafter, such as the long-range ISR/strike aircraft...The core image, which the General put on the table of where the transition needs to go, is the ability to shape a combat cloud as a key element of the battlespace within which the various deployed aircraft interact together to shape air dominance to achieve joint force objectives...

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 16:53
by SpudmanWP
mmm wrote:hell APG-81 antenna is even decade old


Tech Refresh 2 (TR2) comes to the F-35 as part of Block3i.

TR2 contains
The hardware per aircraft includes new radar modules, new Integrated Core
Processor modules and rack, and new electronic warfare modules.


For all intents and purposes, TR2 & new new modes it allows brings the radar up to APG-81(v)2

Re: F-22's APG-77 vs decoys

Unread postPosted: 18 Aug 2015, 17:08
by eloise
SpudmanWP wrote:
mmm wrote:hell APG-81 antenna is even decade old


Tech Refresh 2 (TR2) comes to the F-35 as part of Block3i.

TR2 contains
The hardware per aircraft includes new radar modules, new Integrated Core
Processor modules and rack, and new electronic warfare modules.


For all intents and purposes, TR2 & new new modes it allows brings the radar up to APG-81(v)2

wow, i haven't heard of that

Re: F-22's APG-77 vs decoys

Unread postPosted: 19 Aug 2015, 07:18
by hornetfinn
mmm wrote:
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.


True, in the future there will be better technologies available. AN/APG-77 is one of the earlier operational fighter AESA radars but will likely remain one of the best for a long time. A lot of money and technologies were put into it and it's clear that it's continually upgraded and kept up to date. AWG-9 was one of the earliest planar array radars, but it remained one of the best for several decades. IMO, APG-77 will remain one of the best, if not the best air-to-air radar for a long time as it will likely be continually upgraded when technology advances.

Btw, IMO APG-77 uses digital beamforming, most likely at subarray level. Of course fully digital array with beamforming done at element (module) level would be even better. GaN is definitely a future trend as it offers tremendous advantages compared to GaAs. However all current fighter radar projects use GaAs and it might take 10-15 years before we see GaN fighter radar. Either AN/APG-81 or APG-77 might actually be the first to use it in some future variant.

DEW weapons, cyber warfare and automation were definitely known issues during the days of ATF (basically 1980s), although naturally now we understand the issues better. F-22 has pretty advanced automation and could be upgraded for cyber warfare if required. DEW weapons are nowhere near becoming operational in near term and F-22 might be retired before they are real capability.

Re: F-22's APG-77 vs decoys

Unread postPosted: 09 Oct 2015, 23:38
by mmm
SpudmanWP wrote:
mmm wrote:hell APG-81 antenna is even decade old


Tech Refresh 2 (TR2) comes to the F-35 as part of Block3i.

TR2 contains
The hardware per aircraft includes new radar modules, new Integrated Core
Processor modules and rack, and new electronic warfare modules.


For all intents and purposes, TR2 & new new modes it allows brings the radar up to APG-81(v)2

That's new to me. All I remembered is that the processor is getting replaced. Good for them if they're working on an updated antenna. Can't tell what it will actually be from the excerpt but the expectation is that it will be up to date. Thanks for the info.

hornetfinn wrote:
mmm wrote:
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.


True, in the future there will be better technologies available. AN/APG-77 is one of the earlier operational fighter AESA radars but will likely remain one of the best for a long time. A lot of money and technologies were put into it and it's clear that it's continually upgraded and kept up to date. AWG-9 was one of the earliest planar array radars, but it remained one of the best for several decades. IMO, APG-77 will remain one of the best, if not the best air-to-air radar for a long time as it will likely be continually upgraded when technology advances.

Btw, IMO APG-77 uses digital beamforming, most likely at subarray level. Of course fully digital array with beamforming done at element (module) level would be even better. GaN is definitely a future trend as it offers tremendous advantages compared to GaAs. However all current fighter radar projects use GaAs and it might take 10-15 years before we see GaN fighter radar. Either AN/APG-81 or APG-77 might actually be the first to use it in some future variant.

DEW weapons, cyber warfare and automation were definitely known issues during the days of ATF (basically 1980s), although naturally now we understand the issues better. F-22 has pretty advanced automation and could be upgraded for cyber warfare if required. DEW weapons are nowhere near becoming operational in near term and F-22 might be retired before they are real capability.


I can pretty much agree with everything. Consider how few operational fighter AESA there are even as of today, and those that are on par with APG-77 in terms of technology are only in US service, I've no doubt it is still one of the best today. The lack of serious effort for modernization and a fleet too small to make R&D dollar worthwhile is the real problem.

By emerging technology I really meant to say a battle space with those capability hosted on a variety of platforms, not just their application on F-22. Say assuming the requirement for ATF is formulated today, it could have been better account for those techs. To be fair F-22 did take some time to develop after the end of cold war, it was first of its kind, and having already spent a decade unchallenged.