Long Range IR-Missile

That’s why i don’t prefer over-the-shoulder launches. Missile needs to be in LOAL mode, and that’s a great way to shoot your own wingman in a dense enviroment.

Better way is to use rear-facing launches, and have a rear-facing IRST, or a TWS system.

The main problem with developing long range IR guided missiles that aquire the target after launch is that most IR seekers were not up to the challange.
An IR seeker on a missile like the AIM-9M or R-73 does not see a complete image. It sees hotspots of objects but doesn’t see them as objects, just as areas of intense heat. As such if you added an initial unlocked phase to the missiles flight and then expected it to aquire its target when it got to where the target should be easily visible it might accidently lock onto the right target, but considering all the other warm items like things on the ground or in the air that it might think is the target.
For close combat or lock on before launch use you use some method of pointing the missiles seeker at the target… IR is a high frequency and has excellent angular accuracy. (Think of sitting in a dark room and trying to track the position of a fly with two sensors called your ears using your hearing. With good hearing you might be able to work out the flys position to within the size of a basket ball, but if the lights are turned on and you are allowed to use your eyes your tracking ability will be much better… the size of a marble. Your clumsy attempts to swat the fly with your hand will probably miss because your hands can’t move as fast as your eyes can track… and the fly can move fast.
So when using an old IR missile at close range you point the heat sensitive seeker at the target and get it to memorise that target source of heat… you then fire it towards that source. With a lock on after launch method you have to have some way to tell the missile seeker where the target is, very precisely regards to angle so it can lock on. This is practically impossible so a long range IR missile must actually be an IIR missile able to seek and identify its own targets from an internal database. This is really only an option for AIM-9X and similar missiles. The R-27T uses the same seeker as that used in the R-73, but the larger body means it can move over a wider FOV. (55 degrees + and – at a time when R-73s were 45 degrees + and -).

Hello everyone!

Have long range IR-missiles been developed?

When I think of AMRAAM and Phoenix, they both use inflight datalink to update target information. Why wasn’t that done with terminal IR guidance. Advantage: less costly and completely passive, the attacked aircraft wouldn’ have a clue it is attacked. The missile is still useful for closer ranges (with limitations of course).

Does anybody have input?

At one point they were going to have terminal IR guidance on the AIM-47 but in the end they cancelled it. Also while not an AAM SM-2 Block IVA had a secondary IR terminal guidance and they were going to develope a version of AIM-7 with a secondary IR terminal guidance but as with the AIM-47 it got cancelled. You’ll also want to check this out:

http://www.designation-systems.net/dusrm/m-152.html

specifically the GD/ Westinghouse design.

The adition of the datalink to to the 9X, has more to do with providing a 360 deg. envelope (as Python V) then turning it into a BVR weapon.

Or launching “blind” from the F-22’s side bays?

When I think of AMRAAM and Phoenix, they both use inflight datalink to update target information. Why wasn’t that done with terminal IR guidance.

The currently accepted wisdom is that the R-27T(E) do not have the command datalink of their SARH guided cousins for midcourse guidance. Thus they do not provide a true BVR capability because seeker lock-on of the target is required prior to launch, however they are intended to enable tail-chase shots where the performance of conventional IR SRAAMs would be hopelessly insufficient kinematically.

I believe I recall some info from another forum, saying one of the reasons for not adding the datalink to these models was that the seeker cooling would not have lasted long enough for any long shots.

Edit: Well my memory was off. Since I did at least find the thread, some bits from it:
From an article about the missile by a Vympel designer; Nothing new in regards to this thread apart from confirming that there is no inertial guidance+LOAL capability for long shots against slow targets.
http://forum.lockon.ru/showpost.php?p=222352&postcount=72

On the theoretical performance, from the Su-27S manual; (Of course the long frontal launch range stated would be subject to differing heat signatures.)
http://forum.lockon.ru/showpost.php?p=222186&postcount=46

My memory was off, what I thought I remembered as manual info on the R-27 was a “I heard this from a pilot” quote about about the AIM-9X seeker cooling being usable for (optimum condition) shots of up to 10nm.
Since the R-27ET was intended for the role as stated by Trident, one could perhaps assume that the seeker cooling for this version was sufficient for a 15km tailchase and no more. One could perhaps also speculate on the seeker & coolant technology of the SU at the time, and perhaps also speculate on a “why-not” combination of the large R-27 with a more modern seeker with coolant, plus the family’s datalink.

Although it won’t achieve ranges quite in the MICA class (under comparable launch conditions) the USN is currently working on a datalink for the AIM-9x plus the BLKII
rnd will incorporate pre-programmed loft/Loft glide logic. The combination of these two will significantly extend useable 9x ranges (especially when launched from the F-22) though absolute max ranges will probably be under 40km – limited by the existing motor and the power available for controlled flight (mission duration <=60sec).

The adition of the datalink to to the 9X, has more to do with providing a 360 deg. envelope (as Python V) then turning it into a BVR weapon.

Although it won’t achieve ranges quite in the MICA class (under comparable launch conditions) the USN is currently working on a datalink for the AIM-9x plus the BLKII
rnd will incorporate pre-programmed loft/Loft glide logic. The combination of these two will significantly extend useable 9x ranges (especially when launched from the F-22) though absolute max ranges will probably be under 40km – limited by the existing motor and the power available for controlled flight (mission duration <=60sec).

However note that whilst in *theory* the 9x seeker closely matches or even outperforms the airframe/motor in *practice* under operational conditions the atmosphere doesn’t behave like a theoretical ideal.Hence adding the datalink actually does make sense (because in practice the airframe/motor are frequently not the limiting factors) and hence the USN remarks about potentially doubling the range (i.e. operationally practicable rather than theoretical range).

REFS – see my article JM&R (oct 2005) and B.sweetman’s recent (Feb or Mar 07) article in IDR.

This is interesting, that an inflight guidance via data-link is added to a “short-range” missile. But your points make total sense, that the IR sensor might not acquire the target due to atmospherical conditions and is augmented by other sensors.
Modern IR-AAMs are quite lethal, so that any advantage which keep one out of the kill radius of an opponent are worth exploiting. With such a missile, an incoming opponent can be greeted with a BVR-IRAAM and the firing aircraft can turn around before the other has a firing option.

I know that the IRIS-T (IR-AAM for the Eurofighter) has something comparable, to get target information when launched “over the shoulder”.

lr IIR AIM-9x

Although it won’t achieve ranges quite in the MICA class (under comparable launch conditions) the USN is currently working on a datalink for the AIM-9x plus the BLKII
rnd will incorporate pre-programmed loft/Loft glide logic. The combination of these two will significantly extend useable 9x ranges (especially when launched from the F-22) though absolute max ranges will probably be under 40km – limited by the existing motor and the power available for controlled flight (mission duration <=60sec).

However note that whilst in *theory* the 9x seeker closely matches or even outperforms the airframe/motor in *practice* under operational conditions the atmosphere doesn’t behave like a theoretical ideal.Hence adding the datalink actually does make sense (because in practice the airframe/motor are frequently not the limiting factors) and hence the USN remarks about potentially doubling the range (i.e. operationally practicable rather than theoretical range).

REFS – see my article JM&R (oct 2005) and B.sweetman’s recent (Feb or Mar 07) article in IDR.

The advantage of IR guidance would be that you can also engage stealthy aircraft. I think even a stealthy aircraft like F-35 can be detected, but not sufficient to gain a missile lock. Such a weapon would work best when it is able to receive inputs from several sources, so for example AWACS or other aircraft. Or possible guidance by linked RWR when the stealthy aircraft has its radar activated.

Agree totally

Infrared homing refers to a guidance system which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track it. Missiles which use infrared seeking are often referred to as “heat-seekers”. Infrared (IR) is just below the visible spectrum of light in frequency and is radiated strongly by hot bodies. Many objects such as people, vehicle engines and aircraft generate and retain heat, and as such, are especially visible in the infra-red wavelengths of light compared to objects in the background.
Most infrared guided missiles have their seekers mounted on a gimbal. This allows the sensor to be pointed at the target when the missile is not. This is important for two main reasons. One is that before and during launch, the missile can’t always be pointed at the target. Rather, the pilot or operator points the seeker at the target using radar, a helmet-mounted sight, an optical sight or possibly by pointing the nose of the aircraft or missile launcher directly at the target. Once the seeker sees and recognises the target, it indicates this to the operator who then typically “uncages” the seeker (which is then allowed to follow the target). After this point the seeker remains locked on the target, even if the aircraft or launching platform moves. When the weapon is launched, it may not be able to control the direction it points until the motor fires and it reaches a high enough speed for its fins to control its direction of travel. Until then, the gimballed seeker needs to be able to track the target independently.

Finally, even while it is under positive control and on its way to intercept the target, it probably won’t be pointing directly at it; unless the target is moving directly toward or away from the launching platform, the shortest path to intercept the target will not be the path taken while pointing straight at it, since it is moving laterally with respect to the missile’s view. The original heat-seeking missiles would simply point towards the target and chase it; this was inefficient. Newer missiles are smarter and use the gimballed seeker head combined with what’s known as “proportional guidance” in order to avoid oscillation and to fly an efficient intercept path.

The advantage of IR guidance would be that you can also engage stealthy aircraft. I think even a stealthy aircraft like F-35 can be detected, but not sufficient to gain a missile lock. Such a weapon would work best when it is able to receive inputs from several sources, so for example AWACS or other aircraft. Or possible guidance by linked RWR when the stealthy aircraft has its radar activated.

Hello everyone!

Have long range IR-missiles been developed?

When I think of AMRAAM and Phoenix, they both use inflight datalink to update target information. Why wasn’t that done with terminal IR guidance. Advantage: less costly and completely passive, the attacked aircraft wouldn’ have a clue it is attacked. The missile is still useful for closer ranges (with limitations of course).

Does anybody have input?

One of the major limitations in the past is that in order to give an IR missile a credible BVR capacity, you would have to be able to give it guidence until it can get within its own seeker range. Thus you can see the problem this represents: in order to provide mid-course guidence, you need to know where the target this, this means tracking it with your airplane’s own radar, which in turn would give the game away.

However, with the advent and gradual widespread deployment of AESA radars, it would now be possible to make your vision reality, and I would be very suprised if such weapons are not already in development. Although that is not to say that ARH BVRAAMs are going to become extinct anytime soon. The current trend for ARHAAMs seems to be speed, with new ramjet versions of old favourates being developed by all the major players in the field. The heat generated by ramjet power missiles may render IR seekers useless, so radar may be the only option for such missiles.

It would not be hard to imagine a bit of a split in design philosophies for the next gen BVRAAM, with speed pitched against stealth. It would be interesting to see which faction gains sway in which countries.

The currently accepted wisdom is that the R-27T(E) do not have the command datalink of their SARH guided cousins for midcourse guidance. Thus they do not provide a true BVR capability because seeker lock-on of the target is required prior to launch, however they are intended to enable tail-chase shots where the performance of conventional IR SRAAMs would be hopelessly insufficient kinematically.

Sofar, it looks like Mica IR is the only IR missile with a credible BVR capability.

As much as i know thats not complete picture: R-27T have inertial guidance and so can be launhed against targets what dont change its course (much) without IR seeker locking it prior to launch

The currently accepted wisdom is that the R-27T(E) do not have the command datalink of their SARH guided cousins for midcourse guidance. Thus they do not provide a true BVR capability because seeker lock-on of the target is required prior to launch, however they are intended to enable tail-chase shots where the performance of conventional IR SRAAMs would be hopelessly insufficient kinematically.

Sofar, it looks like Mica IR is the only IR missile with a credible BVR capability.

R-27 (AA-10) has had a medium range and extended range IR guidance package for 20 years now.

IIRC, MICA also has a somewhat long range IR version.