why no close range missile defence for fighters?

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13 years 5 months

Posts: 593

These days, helicopters have lasers that can damage the IR heads on SAMs; ships have long had radar guided guns and missiles to take out low flying anti-ship missiles, and are actively working on even faster lasers; and now, ground vehicles have access to an active denial system that can intercept RPGs seconds after launch, at minimum ranges.

Yet the best defence fighters have against AAMs and SAMs these days are flares, ECM, decoys and manouvering, mostly defensive measures. Why is there no system to actively destroy these missiles, especially since there is often some time between launch and impact, giving time to respond? Plus the IR signature or active radar guidance heads on these missiles are often easy to track, and thus target, especially because missiles tend to fly by very predictable routes. Also, missiles being relatively fragile machines, they need not be destroyed completely, just damaging them slightly or physically obstructing them is likely to take them out of action.

The 70 mm missiles could be used. With a basic IR or radio guided guidance system, these would come relatively cheap. Plus, they're currently being developed into guided missiles for precision ground attack use, meaing you just need to change the guidance system.

The Hydra 70 for example costs $1,000 for the basic missile, add another $4,000 for the guidance system? It has a range of up to 10 km, and a speed of about Mach 3.5.
Against say an AMRAAM ($700,000) with a speed of Mach 4, a first Hydra could be launched to intercept at maximum range, and than the fighter aircraft would have another 8 seconds to launch more Hydra's if the first one failed to stop the enemy missile.
On top of this, the Hydra's could also be used offensively in dog fights, launching a large number of missiles. In a world where fighters are few between and carry a limited number of missiles, this would give the Hydra user a clear advantage in combat endurance.

Another alternative I can think off are basic explosive, launched in great numbers behind or below the aircraft, designed to wander into the enemy missile's flight path and stopping it through sheer explosive and kinetic force, like flying mines.

Original post

Member for

15 years 5 months

Posts: 6,983

Well you have DIRCM, and Iris-t is advertised as a dual-use anti-missile/anti-aircraft missile

In general:
1. Cost
2. Weight
3. Drag
4. RCS

Additionally, with your proposed approach in particular:
6. Accuracy (laser guided rockets are reasonably accurate against *stationary* or slow-moving trucks, but that's a long way from being able to hit a small, fast AAM)
7. Wasted hardpoints

Member for

13 years 5 months

Posts: 593

a good question, how would guided 70 mm rockets compare to the IRIS-T?

>IRIS-T: $500,000/missile, 87.4 kg, one per hardpoint, range 25 km

>guided 70mm: $10,000/missile (estimated price for the laser guided version), 7 kg, 20 per hardpoint, range 10 km

the IRIS-T would have superior range, but can only stop one missile at best. the 70mm, while short ranged, can fire large numbers at a single target, greatly increasing the chance of succes and the number of possible destroyed enemy missiles. especially when a single aircraft is facing multiple AAMs or SAMs, this is a huge advantage

the biggest question would be what guidance system to use. the F-35 is capable of optically tracking missiles 360 degrees and guide it's missile to it by networking. alternatively an IR seeker could be used, I imagine they wouldn't be much more expensive than a laser seeker

the best thing is that these would allow attack craft to actively destroy multiple incomming missiles, effectively elimenating the missile threat

and eventually these might even be used to engage ground targets (like the new Sidewinder can do)

Again, the guidance system accuracy and manoeuvrability of the Hydra are nowhere near good enough to hit a missile, which also accounts for a lot of the very low price tag compared to IRIS-T. No proximity fuze either!

The difference between combat aircraft and helicopters, ground vehicles and ships is that on the one hand, the constraints I mentioned in my first post are much stricter while on the other hand their far superior agility gives a much better chance of evading. It's a trade-off between the drawbacks as mentioned previously and potential benefits of fitting hardkill defences and so far they are failing to justify their inclusion on this basis. However, as hardkill technology becomes less bulky and enemy missiles get harder to spoof or evade, this balance might tip in favour of using them at some point - we're just not quite there yet.

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17 years 10 months

Posts: 297

I believe to have read somewhere that the radar guided Gripen cannon, is accurate enough to take out a front aspect missile.

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15 years 1 month

Posts: 840

What DIRCM system DAMAGES incoming IR missile seeker heads? AFAIK, they work simply by `jamming` them.
And similar systems ARE being developed for fast jets. They are probably harder because the base platform itself is moving and maneuvering at high speeds, i.e. twice the vectors to worry about. Slower platforms probably did get DIRCM first because besides being simpler, they are more vulnerable in the first place.

As mentioned, Hydras are not going to be up to the task, besides being over-kill in all the wrong departments - CERTAINLY not on fast jets, as opposed to slow, essentially non-maneuvering platforms like civil airliners or helicopters. I really think simpe DIRCM `jamming` is going to be the most effective for quite some time... Only thing it wouldn`t work against are NON-IR missiles, and missiles with multiple seekers/sensors. So it will be interesting to see how both short-range and long-range missiles evolve, seeker-wise. Short-range radar-seekers could become worth it if DIRCMs proliferate.

Assuming you want something like this, you would want to reduce the size of them as much as possible to allow for internal launching (you would want at least as many as a normal A2A load-out, and probably signifigantly more). You don`t need the vast majority of propellant that even Hydra`s carry, because you don`t need more than 1-200m of range. Hypothetically against missiles closing from the rear, some sort of parachute could be deployed to cancel forward momentum before a rocket kicks in to intercept the incoming missile. You DO need maneuverability on par with incoming missiles (30-50G) if you expect broad protection (if they have an IR seeker, they can certainly be updated software-wise to avoid `defensive counter fire`), but the most realistic approach here (considering demands on space/etc of the airframe) is a less capable `sub-munition` that is mostly effective against missiles at the EDGE of their NEZ, i.e. when any additional maneuvering would likely lead to a miss. Such a paradigm would seem to call for fusing the `defensive darts` trajectories with the aircraft`s OWN defensive maneuvers, so that the darts can intercept the missile if it adjusts to close with the aircraft, while if it avoids the darts it is maneuvering away from the aircraft.

Again, I don`t see the need for anything besides DIRCM for at least the immediate generation of weapons, though how weapons evolve in response to DIRCM could well trigger the impetus for something like this. Destructive defensive lasers are problematic, any shielding and/or spinning flight profile will drastically increase the time-on-target threshold needed for destruction... If they work, they would work best against incoming missiles able to be targetted from longer distances away. All these developments do beg the question if `dog fighting` will in fact return in some form... :cool:

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13 years 5 months

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intersting replies, a few points:

the reason I'm interested in anti-missile systems is because I'm a UAV buff: I believe they're the future, but they're slow and vulnerable to enemy fighters and missiles. if you could trade missiles efficiently ($10,000 Hydra's vs $1,000,000ish AMRAAMs and S-20s for example), UAVs would dominate the skies through sheer cheap numbers and their expendable nature

I can see that Hydra missile would be much more expensive if built for high G trajectories. however
a) I don't agree that this will always be the case. most missile would fly by a pretty straight and predictable path, at a steady speed, not trying to avoid other aircraft or missiles, making it easy to calculate a point of interception
b) why not install the missile launchers facing the rear? combined with a forward facing pod, this would give a constant front and rear coverage

Member for

18 years 10 months

Posts: 4,472

intersting replies, a few points:

the reason I'm interested in anti-missile systems is because I'm a UAV buff: I believe they're the future, but they're slow and vulnerable to enemy fighters and missiles. if you could trade missiles efficiently ($10,000 Hydra's vs $1,000,000ish AMRAAMs and S-20s for example), UAVs would dominate the skies through sheer cheap numbers and their expendable nature

I can see that Hydra missile would be much more expensive if built for high G trajectories. however
a) I don't agree that this will always be the case. most missile would fly by a pretty straight and predictable path, at a steady speed, not trying to avoid other aircraft or missiles, making it easy to calculate a point of interception
b) why not install the missile launchers facing the rear? combined with a forward facing pod, this would give a constant front and rear coverage

Why not install a mini CIWS with a small radar guided gun to shoot at incoming missiles?

Nic

Member for

15 years 1 month

Posts: 840

CIWS are standard on naval ships. ASM manufacturers respond with unpredictable jagging maneuvers, which are presumed to be somewhat effective if people still buy ASM missiles... not to mention higher tier SAM defenses to shoot down incoming missiles at larger range (which would be un-necessary if CIWS was so effective). A2A missiles are going to be more maneuverable than ASM missiles. So like I said, such a system could help by effectively reducing the NEZ, only missiles with more energy for effective extreme maneuvers would be able to beat the CIWS (current missiles really have much more maneuvering energy than they need except at edge of NEZ).

Of course, the response would just be to convert missiles to cluster munition carriers, imparting their velocity to all the sub-munitions which disperse to independently maneuver to target... It doesn`t take much warhead to take out a jet, and you don`t need that much more propellant either, since all of the sub-munitions have the carrier missile`s final velocity, it`s just a matter of independent seeker heads and maneuvering thrusters. On the flip side, the carrier missile itself has alot of design factors simplified since it doesn`t need superb end-game maneuverabiilty itself, it just needs to build up the max velocity by the time it closes.

Member for

18 years 10 months

Posts: 4,472

Well what AAM is designed to do a random pattern to avoid CIWS though? The energy it has for the end game is not designed for that.

Nic

Member for

15 years 1 month

Posts: 840

Exactly why I`m talking about reducing NEZ.
The missiles are already designed for maneuvering, it`s simply a matter of if there is a CIWS threat, it would make sense to introduce end-game evasive maneuver programming... that`s not really a new field of knowledge.

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15 years 2 months

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I think we will see damaging EM & laser based solutions before we see self-defense missiles.

Member for

13 years 5 months

Posts: 593

fair point, lasers are the future, they've got the potential to make missiles and dog fights a thing of the past, or even air power as a whole because ground forces will be able to deflect any and all air attacks. unless Congress pulls the plug for whatever moronic reason, probably letting the Chinese take the lead

although I expect it'll take at least another decade before we see laser weapons on fighter aircraft, while defence missiles are already a reality with the IRIS-T

all of which is a moot point however, because the West has such overwhelming air power, which it only employs against relatively weak opponents, most of which are many decades away from fielding something like lasers or S-500 SAMs. so there is simply little need for a missile defence system (or a 100%, super-expensive stealth force for that matter)