Go Back   Defense Technology & Military Forum > Global Defense & Military > Air Force & Aviation
Forgot Password? Join Us! Its's free!

Defense News
Land, Air & Naval Forces






Military Photos
Latest Military Pictures

Miramar_14_MV-22_1965a.JPG

Miramar_14_MV-22_0358a.JPG

Miramar_14_GR4_1646a.JPG

Miramar_14_LF_0221a.JPG
Defense Reports
Aerospace & Defence







Recent Photos - DefenceTalk Military Gallery





AIM-120 AMRAAM Pk?

This is a discussion on AIM-120 AMRAAM Pk? within the Air Force & Aviation forum, part of the Global Defense & Military category; I've heard that the AMRAAM's Probability of Kill is somewhere around 43%; however, it seems that this percentage is faulty, ...


Reply
 
LinkBack Thread Tools Rate Thread
Old June 7th, 2013   #1
Banned Member
Private
No Avatar
Join Date: May 2013
Posts: 23
Threads:
AIM-120 AMRAAM Pk?

I've heard that the AMRAAM's Probability of Kill is somewhere around 43%; however, it seems that this percentage is faulty, as it is a ratio of number of missiles launched to number of targets destroyed, which isn't always an accurate ratio for determining a missile's effectiveness (i.e. if two missiles were fired at a target, and both hit it, the Pk would be 50%, even though both missiles successfully intercepted the target). It would seem that this factor would artificially depress a missile's Pk and make it appear less effective than it actually is.

Obviously, official figures are classified, but... would anyone here have a general idea/rough approximation as to what the AIM-120D's abilities are, in terms of the probability of it intercepting an enemy aircraft?
Tico90 is offline   Reply With Quote
Similar Threads
Thread Thread Starter Forum Replies Last Post
Midtguardian Defence Force Bozoo Geo-strategic Issues 51 January 12th, 2009 12:57 PM
AMRAAM and R-77 performance review Awang se Missiles & WMDs 174 October 18th, 2008 06:32 PM
Aim 120D on the F-35? Atilla [TR] Missiles & WMDs 3 June 19th, 2008 02:36 PM
Challenger 2 gets L/55 Waylander Army & Security Forces 20 April 21st, 2006 07:03 PM
Success in AMRAAM Guided Missile Trials for Eurofighter Pathfinder-X Air Force & Aviation 2 March 21st, 2005 08:25 AM

Old June 8th, 2013   #2
Just a bloke
Colonel
No Avatar
Join Date: May 2011
Posts: 1,525
Threads:
That AMRAAM Pk figure was dreamed up by Carlo Kopp through the dodgy use of statistics for "beyond visual range - BVR" engagements only and it was done to "prove" the alleged in-effectiveness of the F-35.

He deliberately excluded "non-BVR" successful warshots, he deliberately excluded instances where more than one missile was successfully fired at a target and he deliberately included instances where missiles were fired WELL out of their NEZ with the pilots aiming to suppress a threat and achieve a "mission kill" knowing full well the missile was unlikely to achieve an actual kill.

By manipulating the figures to suit your agenda you can work out a credible Pk value for all variants of AMRAAM anywhere from 0.43Pk up to about as high as 0.8-0.9Pk.

The fact is, the AMRAAM is the most operationally successful medium range missile in-service today. There is no other current BVR weapon that has demonstrated anywhere near it's operational effectiveness.

The latest AIM-120C7 and AIM-120D missiles are excellent weapons.

End of story.
ADMk2 is offline   Reply With Quote
Old June 8th, 2013   #3
Banned Member
Private
No Avatar
Join Date: May 2013
Posts: 23
Threads:
Ah. That's interesting to hear. On a related note, does anyone have any idea at what approximate range an AIM-120 goes terminal and switches on its radar? The exact figures are undoubtably classified, but does anyone have a rough approximation? From the little I've heard, it seems like the AMRAAM starts up its radar somewhat close to its target, to reduce the time the enemy has to conduct evasive maneuvers or jam it.
Tico90 is offline   Reply With Quote
Old June 9th, 2013   #4
Super Moderator
Lieutenant General
No Avatar
Join Date: Mar 2009
Location: Australia
Posts: 2,555
Threads:
Quote:
Originally Posted by Tico90 View Post
Ah. That's interesting to hear. On a related note, does anyone have any idea at what approximate range an AIM-120 goes terminal and switches on its radar? The exact figures are undoubtably classified, but does anyone have a rough approximation? From the little I've heard, it seems like the AMRAAM starts up its radar somewhat close to its target, to reduce the time the enemy has to conduct evasive maneuvers or jam it.
Without accurate data as a starting point I think it would be pointless to make approximations, as no realistically useful information could be inferred from them. I've heard it said that air to air missile effectiveness is in these times more accurately measured by "no escape zone" than maximum range, but again, these figures are highly classified and speculating about them is very difficult.

AD's comments are highly relevant to anyone wondering about the stated pK of certain missile types. In my opinion, as a civilian the best I can do is try to build a picture of overall capability rather than the specific characteristics of certain missiles and so forth.
Bonza is offline   Reply With Quote
Old June 10th, 2013   #5
Defense Professional / Analyst
Corporal
No Avatar
Join Date: May 2013
Posts: 175
Threads:
Quote:
Originally Posted by Bonza View Post
Without accurate data as a starting point I think it would be pointless to make approximations, as no realistically useful information could be inferred from them. I've heard it said that air to air missile effectiveness is in these times more accurately measured by "no escape zone" than maximum range, but again, these figures are highly classified and speculating about them is very difficult.

AD's comments are highly relevant to anyone wondering about the stated pK of certain missile types. In my opinion, as a civilian the best I can do is try to build a picture of overall capability rather than the specific characteristics of certain missiles and so forth.
Yup, Pk is a lot more complicated than a single baseline number...it depends on the target's capabilities as well, and not just kinematic...countermeasures are another factor as well.

Specifics like an approximate Pk or range from target for seeker turn on are all things that would be classified...you can develop tactics and systems based on approximations as well, just at a lower confidence level.
CB90 is offline   Reply With Quote
Old June 10th, 2013   #6
Just a bloke
Colonel
No Avatar
Join Date: May 2011
Posts: 1,525
Threads:
Quote:
Originally Posted by Tico90 View Post
Ah. That's interesting to hear. On a related note, does anyone have any idea at what approximate range an AIM-120 goes terminal and switches on its radar? The exact figures are undoubtably classified, but does anyone have a rough approximation? From the little I've heard, it seems like the AMRAAM starts up its radar somewhat close to its target, to reduce the time the enemy has to conduct evasive maneuvers or jam it.
First of all, there are a heap of different variants of "AIM-120" out there, so there isn't "one answer" to your question.

The AIM-120C7 standard is the current production standard (the rocket engine production issues, nothwithstanding) and is the most capable operational variant of the AMRAAM missile to date.

The AIM-120D however is in the final stages of it's development and IOC may soon be declared for that weapon. One of the big developments that -D brings over the earlier variants is improved ballistic path and improved targetting capability.

The active radar seeker of the AMRAAM is a small radar system. Depending on the EM environment, the presence of jamming, the firing mode the pilot has employed on the weapon (bearing in mind these missiles have other targetting methods than simply by active radar) the range before that active seeker "goes active" will always vary.

There are a range of figures relating to missile launches. They include RMAX, (maximum range the weapon can be fired) WEZ (theoretical zone within which a weapon can be employed - weapons engagement zone) and NEZ, (no escape zone) or "the basket" the zone in which the weapon is most likely to successfully engage it's intended target.

AMRAAM from it's beginning boasts active, semi-active and inertial reference guidance modes, with later variants including "home on jam" capability, 2 way data-link capability (to among other things expand off-board targetting control of the weapon in-flight) and GPS/INS guidance assistance. The weapon therefore may not always go "active". Many current weapon systems do not (naval and land based surface to air missiles especially) and AMRAAM maintains that capability.

You were right in that the figures for the active seeker are classified, but it also depends on the target. Given the nature of radar, engaging a Hercules or a C-17 is going to be a lot easier on the seeker than engaging a relatively small fighter...
ADMk2 is offline   Reply With Quote
Old June 12th, 2013   #7
Banned Member
Private
No Avatar
Join Date: May 2013
Posts: 23
Threads:
Quote:
Originally Posted by ADMk2 View Post
First of all, there are a heap of different variants of "AIM-120" out there, so there isn't "one answer" to your question.

The AIM-120C7 standard is the current production standard (the rocket engine production issues, nothwithstanding) and is the most capable operational variant of the AMRAAM missile to date.

The AIM-120D however is in the final stages of it's development and IOC may soon be declared for that weapon. One of the big developments that -D brings over the earlier variants is improved ballistic path and improved targetting capability.

The active radar seeker of the AMRAAM is a small radar system. Depending on the EM environment, the presence of jamming, the firing mode the pilot has employed on the weapon (bearing in mind these missiles have other targetting methods than simply by active radar) the range before that active seeker "goes active" will always vary.

There are a range of figures relating to missile launches. They include RMAX, (maximum range the weapon can be fired) WEZ (theoretical zone within which a weapon can be employed - weapons engagement zone) and NEZ, (no escape zone) or "the basket" the zone in which the weapon is most likely to successfully engage it's intended target.

AMRAAM from it's beginning boasts active, semi-active and inertial reference guidance modes, with later variants including "home on jam" capability, 2 way data-link capability (to among other things expand off-board targetting control of the weapon in-flight) and GPS/INS guidance assistance. The weapon therefore may not always go "active". Many current weapon systems do not (naval and land based surface to air missiles especially) and AMRAAM maintains that capability.

You were right in that the figures for the active seeker are classified, but it also depends on the target. Given the nature of radar, engaging a Hercules or a C-17 is going to be a lot easier on the seeker than engaging a relatively small fighter...
So the current versions of the AIM-120 have the ability to hit their target without ever going active?

It would seem like that would give an aircraft such as the F-35 a good ability to improve the missile's Pk (whatever it may be). Since an aircraft's radar only scans a maximum of 120 degrees around the nose of the aircraft (and earlier radars have an even smaller azimuth), and an IRST system scans a much, much thinner region, if the F-35 manage to find the opponent aircraft before it finds them, the F-35 could maneuver into the 240 degree region around the aircraft not being observed by the IRST or radar (some Russian aircraft have backwards-looking radar, but that would still leave the sides of the aircraft without any kind of sensor besides ESM). In that position, the F-35 could fire the AIM-120 and use the datalink to guide it to the target. The F-35 uses an AESA radar, and because the AIM-120 was guided by a datalink (and because the datalink currently being developed for the F-35 is LPI), it wouldn't use its own radar, so the chances of the opponent's aircraft's ESM systems detecting either the aircraft or the missile would seem to be very low.

In this situation, both the aircraft and the missile wouldn't be detected -- the F-35 would detect the opponent's aircraft before it detected them (it would probably have a good ability to do this because of the DAS), and would maneuver into a position where both the aircraft and the AIM-120 wouldn't be able to be detected by either the plane's radar or IRST/thermal missile launch warning system. Furthermore, because the only radar in use would be the F-35's AESA/LPI radar, the opponent's ESM shouldn't be able to detect either the aircraft or the missile.

In this situation, it would seem like the opponent's aircraft would have no knowledge of where the F-35s were, or that a missile had been fired, until the AIM-120 detonated... this would give them no time to evade the missile, electronically attack the missile, or attempt to deceive the missile by either firing chaff or descending to a location with significant radar clutter.

Of course, that's all just my speculation. Is that sort of situation actually possible or feasible, or is there some gaping hole in my reasoning?
Tico90 is offline   Reply With Quote
Old June 12th, 2013   #8
Defense Enthusiast
Lieutenant
SpudmanWP's Avatar
Join Date: Aug 2005
Location: United Socialist Cities of California
Posts: 585
Threads:
You have to active at some point for terminal guidance.

Even with the best datalinks, you will only get the AMRAAM to within a 100 meters or so due to latency and target resolution issues.

Now, if & when they come out with a dual-mode seeker (IR & EM) then it's a whole new ballgame.
SpudmanWP is offline   Reply With Quote
Old June 12th, 2013   #9
Just a bloke
Colonel
No Avatar
Join Date: May 2011
Posts: 1,525
Threads:
Quote:
Originally Posted by Tico90 View Post
So the current versions of the AIM-120 have the ability to hit their target without ever going active?

It would seem like that would give an aircraft such as the F-35 a good ability to improve the missile's Pk (whatever it may be). Since an aircraft's radar only scans a maximum of 120 degrees around the nose of the aircraft (and earlier radars have an even smaller azimuth), and an IRST system scans a much, much thinner region, if the F-35 manage to find the opponent aircraft before it finds them, the F-35 could maneuver into the 240 degree region around the aircraft not being observed by the IRST or radar (some Russian aircraft have backwards-looking radar, but that would still leave the sides of the aircraft without any kind of sensor besides ESM). In that position, the F-35 could fire the AIM-120 and use the datalink to guide it to the target. The F-35 uses an AESA radar, and because the AIM-120 was guided by a datalink (and because the datalink currently being developed for the F-35 is LPI), it wouldn't use its own radar, so the chances of the opponent's aircraft's ESM systems detecting either the aircraft or the missile would seem to be very low.

In this situation, both the aircraft and the missile wouldn't be detected -- the F-35 would detect the opponent's aircraft before it detected them (it would probably have a good ability to do this because of the DAS), and would maneuver into a position where both the aircraft and the AIM-120 wouldn't be able to be detected by either the plane's radar or IRST/thermal missile launch warning system. Furthermore, because the only radar in use would be the F-35's AESA/LPI radar, the opponent's ESM shouldn't be able to detect either the aircraft or the missile.

In this situation, it would seem like the opponent's aircraft would have no knowledge of where the F-35s were, or that a missile had been fired, until the AIM-120 detonated... this would give them no time to evade the missile, electronically attack the missile, or attempt to deceive the missile by either firing chaff or descending to a location with significant radar clutter.

Of course, that's all just my speculation. Is that sort of situation actually possible or feasible, or is there some gaping hole in my reasoning?
You are imagining a scenario where an F-35 and an opponent face off, mano e mano.

Where 1 aircraft's advantages are pitted against another aircraft's advantages.

Warfare doesn't work that way and hasn't worked that way since a person realised he could have a friend help him fight his enemies...

When more than one "thing" attacks another "thing" all sorts of dynamics come into play.

So it is in modern times with air to air warfare. It is a systems event. Not a fighter X v fighter Y type scenario.

Why would the operator of fighter X concern himself with the capability of the relatively small radar he has on-board his own aircraft, let alone the radar seeker on an air to air missile, when he can be fed far greater targetting information (fidelity speaking) from off-board sensor systems?

You kind of touched on several of the intended advantages of the F-35. It's low observability and it's situational awareness (both off-board and on-board) advantages are most directly intended to improve it's ability to position itself to effectively employ a weapon. THAT is why the majority of the effort in developing this fighter has gone into the elements that truly matter, when considering or not to employ a weapon.

Some who still think that a 0.5 mach difference in top speed, a few seconds worth of acceleration or some part of a 1G difference in some parts of the sustained turning operating envelope (in a "clean" configuration) actually matter in modern warfare are so delusional their opinions aren't even worth discussing. If the "advantages" that "other" fighter has, doesn't actually help them put a weapon on their enemy FIRST, then how are they really "advantages"?

In answer to your question, yes. The AMRAAM can achieve a kill without it's radar seeker going active.
ADMk2 is offline   Reply With Quote
Old June 12th, 2013   #10
Just a bloke
Colonel
No Avatar
Join Date: May 2011
Posts: 1,525
Threads:
Quote:
Originally Posted by SpudmanWP View Post
You have to active at some point for terminal guidance.

Even with the best datalinks, you will only get the AMRAAM to within a 100 meters or so due to latency and target resolution issues.

Now, if & when they come out with a dual-mode seeker (IR & EM) then it's a whole new ballgame.
All AMRAAM variants have legacy semi-active modes, ala AIM-7...

The missile itself doesn't have to go active.
ADMk2 is offline   Reply With Quote
Old June 12th, 2013   #11
Defense Enthusiast
Lieutenant
SpudmanWP's Avatar
Join Date: Aug 2005
Location: United Socialist Cities of California
Posts: 585
Threads:
IIRC the AMRAAM's SAR mode would require the F-35 to use a non-LPI mode of it's radar which would seriously degrade it ability to keep it's presence unknown.

In either case, something has to go Active in the clear (non-LPI), the F-35 or the AMRAAM.
SpudmanWP is offline   Reply With Quote
Old June 12th, 2013   #12
Banned Member
Private
No Avatar
Join Date: May 2013
Posts: 23
Threads:
Quote:
Originally Posted by SpudmanWP View Post
IIRC the AMRAAM's SAR mode would require the F-35 to use a non-LPI mode of it's radar which would seriously degrade it ability to keep it's presence unknown.

In either case, something has to go Active in the clear (non-LPI), the F-35 or the AMRAAM.
I guess in that case it would be a tradeoff of sorts -- what do you want the enemy's ESM to see, the F-35 or the AMRAAM? I guess if you wanted to conduct a complete surprise attack, it would be better to close to AIM-9X range.

Although the datalink wouldn't be able to guide the missile, couldn't it be used to aid the missile in countermeasures rejection? Besides standard jamming, one method used to decoy missiles is repeater jamming (or DRFM), which some (I.e. Kopp and Goon) see as the end-all in air-air warfare. However, repeater jamming depends on picking up the radar emissions of the missile/aircraft -- if the ESM doesn't detect the radar (such as if the radar is AESA, a la F-35), it doesn't have any signal to repeat back to the receiver, and so it can't create false targets.

In this situation, couldn't the F-35 (or any AESA-operating aircraft, such as the E-2D, F-22, F-15, F/A-18E/F, etc), use its LPI to defeat DRFM? It would seem that such an aircraft would be able to "show" the missile which target is real -- because it wouldn't be receiving false targets, it could indicate to the AMRAAM which target is the actual one, allowing it to hit an aircraft employing DRFM. Also, because any AESA-equipped aircraft in the area could do this, the launching aircraft wouldn't be restricted to flying straight at the target to keep it in view of its radar, unlike earlier SARH. I wonder if anyone has ever informed the folks at APA about this...

So, could an F-35 use its AESA radar and datalinks to do this? If what I've described is indeed feasible, it would seem to reduce the usefulness of repeater jammers...
Tico90 is offline   Reply With Quote
Old June 12th, 2013   #13
Defense Enthusiast
Lieutenant
SpudmanWP's Avatar
Join Date: Aug 2005
Location: United Socialist Cities of California
Posts: 585
Threads:
SARH mode can also have its advantages, especially against newer jammers that are AESA based.

In SARH mode, the AAM homes in on the reflections of the transmitting aircraft. To be effective, a jammer has to focus it’s energy at the receiver, not the transmitter. This is hard to do with an AAM that is flying in a high arch and in SARH mode. If the jammer goes all-aspect, the AAM can also use HOJ mode.

In the case of a F-35, a non-shooter at 50+ miles could go active and still not give his position away as the only thing the target would know is the bearing that the radar is coming from, not the range.

Then there is the whole multiple SARH transmitters vs a single target and which one do you try to jam.

As to Countermeasures, yes the datalink would help the AAM by giving it the true location of the target and the AAM being able to tell the F-35 the stats of its track.
SpudmanWP is offline   Reply With Quote
Old June 12th, 2013   #14
Banned Member
Private
No Avatar
Join Date: May 2013
Posts: 23
Threads:
Quote:
Originally Posted by SpudmanWP View Post
SARH mode can also have its advantages, especially against newer jammers that are AESA based.

In SARH mode, the AAM homes in on the reflections of the transmitting aircraft. To be effective, a jammer has to focus it’s energy at the receiver, not the transmitter. This is hard to do with an AAM that is flying in a high arch and in SARH mode. If the jammer goes all-aspect, the AAM can also use HOJ mode.

In the case of a F-35, a non-shooter at 50+ miles could go active and still not give his position away as the only thing the target would know is the bearing that the radar is coming from, not the range.

Then there is the whole multiple SARH transmitters vs a single target and which one do you try to jam.

As to Countermeasures, yes the datalink would help the AAM by giving it the true location of the target and the AAM being able to tell the F-35 the stats of its track.
So if a missile was launched in SARH mode, outside the coverage of the enemy aircraft's radar/IRST, wouldn't that cause the opponent to be unaware of the presence of the AMRAAM until he was actually hit? He would know that something had been launched, of course, due to the fact that he was being "locked on" by a FCR, but without knowing where the missile was, wouldn't that prevent him from undergoing evasive maneuvers or an electronic attack?

Also, if the bearing of an F-35 was known (due to the use of SARH), but the range was not, would that be a major danger? It would seem that, without range data, the aircraft being attacked would be unable to fire a BVR missile, and the fact that the use of terminal SARH means that the F-35 would only be illuminating for a very brief period of time would prevent the opposing aircraft from conducting a WVR interceptbefore the F-35 went cold and "disappeared" again.
Tico90 is offline   Reply With Quote
Old June 12th, 2013   #15
Defense Professional / Analyst
Corporal
No Avatar
Join Date: May 2013
Posts: 175
Threads:
Quote:
Originally Posted by Tico90 View Post
Although the datalink wouldn't be able to guide the missile, couldn't it be used to aid the missile in countermeasures rejection?
Yes. However, datalinks are also vulnerable to jamming.

Quote:
Originally Posted by Tico90 View Post
Besides standard jamming, one method used to decoy missiles is repeater jamming (or DRFM), which some (I.e. Kopp and Goon) see as the end-all in air-air warfare. However, repeater jamming depends on picking up the radar emissions of the missile/aircraft -- if the ESM doesn't detect the radar (such as if the radar is AESA, a la F-35), it doesn't have any signal to repeat back to the receiver, and so it can't create false targets.
The idea that some people have that DRFM is the Konami cheat code of the EM world is ridiculous. That said, just because you have an AESA (LPI) radar does not mean it is undetectable.

Quote:
Originally Posted by Tico90 View Post
In this situation, couldn't the F-35 (or any AESA-operating aircraft, such as the E-2D, F-22, F-15, F/A-18E/F, etc), use its LPI to defeat DRFM? It would seem that such an aircraft would be able to "show" the missile which target is real -- because it wouldn't be receiving false targets, it could indicate to the AMRAAM which target is the actual one, allowing it to hit an aircraft employing DRFM.
That would depend on how the seeker works in a SARH mode, and what it requires from the illuminating radar. I suspect this is the reason for the earlier comment by someone that operating in this mode takes the AESA radar out of the "LPI" mode. I would speculate the legacy seeker on an AMRAAM is not frequency agile and that an illuminating radar has to work in continuous wave on a fixed frequency.
I can also pretty much guarantee a DRFM vulnerability study was done for AMRAAM.

Quote:
Originally Posted by Tico90 View Post
Also, because any AESA-equipped aircraft in the area could do this, the launching aircraft wouldn't be restricted to flying straight at the target to keep it in view of its radar, unlike earlier SARH. I wonder if anyone has ever informed the folks at APA about this...
Probably several people, if they didn't already think of it themselves.

Quote:
Originally Posted by Tico90 View Post
So, could an F-35 use its AESA radar and datalinks to do this? If what I've described is indeed feasible, it would seem to reduce the usefulness of repeater jammers...
In theory, yes. I would guess that optimally the AESA operates in a LPI mode, sends midcourse guidance to put the weapon in its no escape zone relative to the target, then the seeker goes active at the last possible minute. I have no idea how much time it takes a DRFM jammer to recognize and start jamming a missile seeker. And at that point and with that geometry, attempting range deception may be pointless, as the missile may get close enough for the proximity fuse to initiate. Unless they were able to jam the fuze to jam the proximity signal. Which would depend on the jam resistant properties of the fuse.
CB90 is offline   Reply With Quote
Reply

Thread Tools
Rate This Thread
Rate This Thread:


All times are GMT -4. The time now is 03:41 AM.