ARMs against ships?

Came across this here:
http://www.selex-sas.com/EN/Common/files/SelexSAS_UK/pdf_datasheet/radar/picosar2.pdf

For all those, who wondered what the minimum real-world number of T/R elements for a AESA could be. And these elements are not overly sophisticated, so I guess a 400cm² array isn’t too much to expect. Would nicely fit a, say, Standard or a Harpoon.

Can’t wait so see such a seeker in a missile!

Realistically if I was holding a contact I believed was a Kirov on the surface plot it wouldnt be an F-18 with an AGM-88 I’d be launching. It would be an SH-60 with an SSQ-86!!! 🙂

Good point. 🙂

If your holding a contact on Hawkeye at extended range you’ve still got very little unfortunately. Unless the big squiggle lights up with his Top Dome all you’ve got is a large contact probaby with an Oko airborne set emissions somewhere down a neighbouring radial. Thats not going to give you enough to shoot on unless you are very, very sure there is nothing else in the area!.

Realistically if I was holding a contact I believed was a Kirov on the surface plot it wouldnt be an F-18 with an AGM-88 I’d be launching. It would be an SH-60 with an SSQ-86!!! 🙂

Only if you know where to shoot the SLAM-ER’s in the first place!. If you dont know the range how do you coordinate the HARMs to be in the seeker basket when the ‘target ships’ light up the SLAMs?.

If you take an engagement in artificial isolation and have a cooperatively emitting target, without over the horizon lookdown radar coverage and CEC, sitting in blissful isolation than yes, theoretically, the dual ARM/AShM strike will work.

Against such a modest target though the simple expedient of sending up a few additional AShM shooters to saturate the targets available fire channels achieves pretty much the same thing though!.

The ARM might give the target an additional threat to deal with but offboard active decoys like Siren or Nulka could render that threat impotent and then, if you are depending on the ARMs to ‘shoot-in’ the AShM’s you are probably looking at a failed strike. If the target is as modest as the one envisaged here just over-saturate the poor thing and be done with it!.

I was thinking of a CVBG going against an opposing force. The CVBG could be looking with Hawkeyes. The idea being with something like a Kirov or something is to get it to activate it’s radars.

Only if you know where to shoot the SLAM-ER’s in the first place!. If you dont know the range how do you coordinate the HARMs to be in the seeker basket when the ‘target ships’ light up the SLAMs?.

If you take an engagement in artificial isolation and have a cooperatively emitting target, without over the horizon lookdown radar coverage and CEC, sitting in blissful isolation than yes, theoretically, the dual ARM/AShM strike will work.

Against such a modest target though the simple expedient of sending up a few additional AShM shooters to saturate the targets available fire channels achieves pretty much the same thing though!.

The ARM might give the target an additional threat to deal with but offboard active decoys like Siren or Nulka could render that threat impotent and then, if you are depending on the ARMs to ‘shoot-in’ the AShM’s you are probably looking at a failed strike. If the target is as modest as the one envisaged here just over-saturate the poor thing and be done with it!.

Couldnt agree more with that sentiment…with the one additional comment….that, irrespective of all other consideration, any targetting method that absolutely depends on the target being complicit must be viewed as one with a great window of vulnerability to deception.

So you coordinate your attack. Launch a bunch of SLAM-ERs or something and have HARMs enter the area around the same time. The target is either going to do nothing and get hit by the SLAM-ERs or emit and get hit by the HARMs.

Plane,

The initial targeting issue is moot. You can fire an ARM using exactly the same launch triggers as a regular AR anti-ship missile.

Its a LOT more complex than that I’m afraid. IF you have a target out in the clear blue, with no clutter or non-hostile vessels, emitting on an identifiable military radar set I’d agree that firing an ARM or an ARH skimmer etc is a moot point. The chances of having a target such as that described are extraordinarily small. I dont know of any developed western navy who’s surface warfare officers ops manual doesnt start with the words, in big friendly letters, ‘Dont Emit’.

As I stated, and Crobato has alluded to, the idea for the side attacking the ships is to get those vessels to transmit on anything identifiable for long enough to develop a track. Simply put because that is the only chance, outside of some very good passive sonar assets, that a target ID can be derived with a wide-area sensor. The contest is between a navy that can develop its battlespace picture with offboard or passive assets and an opponent striving to present an unlocated/unidentified enemy with a serious enough threat to get him to unmask.

And the multi-platform solution you describe is truly a best-case scenario that only relatively few navies can hope to emulate for many years to come. If your enemy is USN, well whatever you try is up against stiff competition, but if your neighbour has a modest navy, well 24-7 UAV coverage and good comms discipline are well, less likely.

Again not such a simple issue to sketch over, Plane, only a relatively few navies have the capability to be aggressively acting in another countries waters beyond the scope of friendly ground-based airpower in the first place…friendly airpower being in this context a source of offboard information that would be tapped well in advance of any intent to use ownship sensors!.

Any Navy that will be in a position to put a task group in hostile waters would, by definition, have counter-detection as its first and over-riding concern. The first principle of naval manoeuvre in opposed waters is the denial of information to the opponent…even if that limits your own tactical options. This is simply because having your naval assets sunk is a lot more limiting!.

Crobato,

Generally its better just to shoot the thing down with a gun CIWS. If its drawn to the CIWS radar it will make a beeline to the gun which allows for a head shot.

No its better to not be found or to decoy off any speculatively launched inbounds that have ‘got lucky’. As soon as you initiate contact with a radar-guided CIWS you are identified. After that point you are in an attritional situation whereby you have to hope that the opposing force cannot bring sufficient firepower to bear to saturate your, very finite, defensive potential. The only other alternatives are to try and decoy with the group ‘identified’ by the enemy and detach a manoeuver group to exploit while the decoys get pounded on or turn, run and try again on another threat axis.

Nicolas, Planesman, you can troll out a fleet’s SAM defenses to activate by sending out a first wave of AshMs, UCAVs and even target drones (e.g. Coyotes), then follow that up with the HARMs.

AShMs and target drones are pointless. If they are non-threatening its too easy to ignore them.

You need to develop the technology and send out UAV’s or high-endurance UCAV’s. The Chinese are, seemingly, starting down this path to an extent and its going to be fascinating to see if they can really exploit the technology they are developing.

GlobalHawk/Mariner kind of UAV’s, radar-equipped, mass produced and supported by a similar air vehicle UCAV packing dozens of Viper Strike type glide munitions with IIR or MMW seekers. The operational concept would be that you have dozens of them at any one time along your coast on racetrack orbits in sensor ‘belts’. Maybe one band at 200nm out then another at, perhaps, 400nm. The UAV’s equipped with swarm logic such that any one detecting a threat to itself calls for all of the other nearby vehicles to concentrate around its position in a, say, 200nm radius circle.

What you do, with such a UAV arrangement, is force the naval group attempting theatre entry to engage those search assets as a precursor to any theatre entry. Any attempt at deceptive manoever stands the risk of detection and very short notice engagement with clouds of small, passive, smart projectiles saturating and mission-killing your pickets whilst identifying targets for conventional follow-on assets. The alternative, the widespread engagement of the UAV’s, requires considerable application of force and is readily identifiable even if you just observe UAV’s dropping off the scope!.

Chaff always interferes no matter what. Blinding is not necessary but a degradation of your own radars and datalinks is still a result. Does not change if thrown to the side anyway.

No YF is quite right here. Chaff is tuned (cut) to the frequency of the sets its trying to defeat. No-one uses chaff that would interfere with the frequencies used in their own search sets. This is for the same reason that people dont knowingly use jammers that are tuned to the same frequencies as their own systems!. Sort of a basic premise in EW is that its bad to degrade your own systems and can lead to much sulking in ops rooms!.

This form of linear phase array either only scans in elevation or horizon, and is commonly revolved around a pedestal for a 360 degree coverage and scan.

You are talking about a mechanical rotator search radar. Such a set can be used to illuminate a chaff cloud for bounce-effect as it will appear to have the same interval as the original search asset anyway!. Thats not what YF is talking about though, he’s talking about a full PESA/AESA set capable of beamsteering and/or multiple beamforming. In the latter case it could be conceivable to have multiple chaff clouds illuminated by several different frequencies and all ‘sources’ equally freq-agile. Without doppler to rely on thats a smart ARM that could guarantee a legit target strike.

Personally I find anti radiation homing to be overblown in its effectiveness as an anti-ship guidance method. It has advantages and weaknesses just like other seeker methods.

Couldnt agree more with that sentiment…with the one additional comment….that, irrespective of all other consideration, any targetting method that absolutely depends on the target being complicit must be viewed as one with a great window of vulnerability to deception.

ARM are way cheaper

Yes indeed, why use ARMs, when the same limited quantity of aircraft can also be fully equipped with AshMs. The answer to that question, is that you can involve aircraft that is not capable of launching AshMs but are ARMs capable.

At least in the case of the US a HARM is going to be a lot harder to hit than a Harpoon and they can get more of them in the air at a time to saturate the target. Take out it’s radars and even the Kirov becomes managable.

What advantage is there to using ARMs then as opposed to normal radar or IR guided missiles?

Yes indeed, why use ARMs, when the same limited quantity of aircraft can also be fully equipped with AshMs. The answer to that question, is that you can involve aircraft that is not capable of launching AshMs but are ARMs capable.

This brings you to a third kind of missile that can be used against a ship, which are electro-optically guided ones, e.g. Kh-59, SLAM. You can involve aircraft capable of using this, but not necessarily capable of using an AshM or ARM.

Which is inaccurate wnough to not hit even a stationary target, least of all a moving one.

Not exactly. An ARM’s accuracy depends on the resolution of the radar it’s homing on. And besides, some ARMs are supersonic, and yet small. So when detected, it may be already too late. Since ARMs are meant to disable radar, they are set for a proximity explosion, so they don’t require a direct hit to disable radar.

A weakness, but how big it is depends on how big a NULL is generated. If combined with a CEC like system, then this is essentially not a problem at all.

I’m not sure if how you intend to do that, if you got AshMs coming on the same vector.

Furthermore, you’re making a guess that the missile is an ARM, and not an optically or thermally guided one. Just too risky.

Chaff operate in different wavelengths, so even if they are thrown in front of the ship they may not necessarily blind it. Who said they have to be thrown to the front and not offset to a side anyway?

Chaff always interferes no matter what. Blinding is not necessary but a degradation of your own radars and datalinks is still a result. Does not change if thrown to the side anyway.

Are you aware of the capabilities of phased array radars?

Indeed I am. Also the different types and their limitations.

Not all phased arrays are SPY-1s types you know, the type that uses individual phase shifters. A common design for a phased array AEW radar consists of a face that is an entire linear phase shifter by itself, or a face with serial linear phase shifters. This form of linear phase array either only scans in elevation or horizon, and is commonly revolved around a pedestal for a 360 degree coverage and scan. Examples range from the Fregat, TRS to SMART. At the same time, many ships still use all forms of mechanical revolving arrays, example, AN/SPS-49.

And decoys meant to replicate these signals as well.

Adds to the ship burden of having to carry multiple kinds of decoys, right? Space used for decoy means less for other things. And besides, decoys can also affect your own signals since they emit a similar waveform. Also the effectiveness of the decoy is subject to the ARM’s software. An ARM is always confronted by different signals simultaneously; differentiation and discrimination is part of its job.

Personally I find anti radiation homing to be overblown in its effectiveness as an anti-ship guidance method. It has advantages and weaknesses just like other seeker methods.

I won’t give a hoot of the seeker if I have enough gun or missile CIWS. Just shoot down everything in sight, regardless and don’t minding whatever seeker they’re using.

Assumes the missile is properly identified as a HARM and not as an AshM. Usually the means if you detect the missile without any emission like AshM waveforms coming from it. The caveat to that if the HARMs are either followed or preceded by a wave of emitting AshMs.

What advantage is there to using ARMs then as opposed to normal radar or IR guided missiles?

When a HARM loses guidance, it reverts to its INS, and continues on the same direction it received the last valid signal.

Which is inaccurate wnough to not hit even a stationary target, least of all a moving one.

If you have a NULL area, it also becomes a blind spot for the ship if there are incoming AshMs behind it.

A weakness, but how big it is depends on how big a NULL is generated. If combined with a CEC like system, then this is essentially not a problem at all.

Early warning radars generally revolve around a pedestal and scan for a 360 degrees. That would make it difficult to do the above. If you throw chaff in front of the ship’s radar scan, you will also end up blinding the ship, as well as all your neighbors and the area behind the chaff becomes a blind spot.

Chaff operate in different wavelengths, so even if they are thrown in front of the ship they may not necessarily blind it. Who said they have to be thrown to the front and not offset to a side anyway?

If you decide to use you SAM radar beam to illuminate the chaff, then that radar beam isn’t being used to illuminate something else.

Are you aware of the capabilities of phased array radars?

HARMs can be drawn to ECM and potentially even to datalinks.

And decoys meant to replicate these signals as well.

Personally I find anti radiation homing to be overblown in its effectiveness as an anti-ship guidance method. It has advantages and weaknesses just like other seeker methods.

c) steer a radar NULL onto the seeker and deny it guidance without affecting own-ship effectiveness.

d) if part of a CEC system, shut down own ship radars without losing warfighting effectiveness.

Assumes the missile is properly identified as a HARM and not as an AshM. Usually the means if you detect the missile without any emission like AshM waveforms coming from it. The caveat to that if the HARMs are either followed or preceded by a wave of emitting AshMs.

When a HARM loses guidance, it reverts to its INS, and continues on the same direction it received the last valid signal.

If you have a NULL area, it also becomes a blind spot for the ship if there are incoming AshMs behind it.

e) fire chaff and illuminate it with own ship radar to make it look like another emitting ship.

Early warning radars generally revolve around a pedestal and scan for a 360 degrees. That would make it difficult to do the above. If you throw chaff in front of the ship’s radar scan, you will also end up blinding the ship, as well as all your neighbors and the area behind the chaff becomes a blind spot.

If you decide to use you SAM radar beam to illuminate the chaff, then that radar beam isn’t being used to illuminate something else.

HARMs can be drawn to ECM and potentially even to datalinks.

and probably many other things that can be done that isn’t known publicly. ARMs just utilise another form of guidance that looks impressive conceptually, but is just as subject to countermeasures as any other form of guidance.

Generally its better just to shoot the thing down with a gun CIWS. If its drawn to the CIWS radar it will make a beeline to the gun which allows for a head shot.

Nicolas, Planesman, you can troll out a fleet’s SAM defenses to activate by sending out a first wave of AshMs, UCAVs and even target drones (e.g. Coyotes), then follow that up with the HARMs.

I think what would be pretty naughty would be to create an ARM that could just emit radar waves on the same frenquency as, say, a Harpoon, but would then home directly on the ship’s fire control radar once it’s turned on. Or it could even home on jamming.

But I think the best way would be to create a stealthy ARM that you could shoot very high up above the area where the enemy ships are in a ballistic form, then send a salvo of AShM, and while the ship would be busy defending against them, your stealthy ARM would dive on the ships from high up homing on their defensive radars.

Nic

a) turns on all it’s AD radars, attempts to illuminate the attacking missile for intercept with guns and missiles.

b) does nothing.

c) steer a radar NULL onto the seeker and deny it guidance without affecting own-ship effectiveness.

d) if part of a CEC system, shut down own ship radars without losing warfighting effectiveness.

e) fire chaff and illuminate it with own ship radar to make it look like another emitting ship.

and probably many other things that can be done that isn’t known publicly. ARMs just utilise another form of guidance that looks impressive conceptually, but is just as subject to countermeasures as any other form of guidance.

Not blindly arguing my case but I’m not sure what you’re saying discounts the argument for ARM guidance Jonesy.

The initial targeting issue is moot. You can fire an ARM using exactly the same launch triggers as a regular AR anti-ship missile. In both cases they are LOAL even at relatively short ranges. So the ARM approaches the target as per an AR missile then scans for emissions.

And the multi-platform solution you describe is truly a best-case scenario that only relatively few navies can hope to emulate for many years to come. If your enemy is USN, well whatever you try is up against stiff competition, but if your neighbour has a modest navy, well 24-7 UAV coverage and good comms discipline are well, less likely.

Another assumption would be that ARMs actually target the antenna. Altitude offsets/lateral (to hit the optimum part of the ship) and coupling with IIR tech is just SOFTWARE. It’s cheep and easy except for testing.

Scenario. ARM-AShM is launched following similar profile to regular anti-ship missile. The enemy fleet has numerous measures to detect the missile, or part of it’s launch (illumination from launch platform or targeting platform, radio altimeter emissions, etc etc). The enemy detects the attack and either:

a) turns on all it’s AD radars, attempts to illuminate the attacking missile for intercept with guns and missiles.

b) does nothing.

In case A) it has made itself a beacon. In B), well that’s hardly what a commander would do(?).

Surely the one thing all warships do when they detect an incoming missile is switch on their FCRs? Ignore the chaff, ignore the flares, just go for the radar with analtitude offset depending on the type of radar. Even build a “picture” of the ship by triangulating various emmissions in the final moments before impact?

The problem here starts one step backwards. In order to fire the ARM you need its target to be emitting on a militarily recognisable radar. Under most operational conditions surface group commanders will strive to avoid having to do that. They will seek to use offboard assets wherever possible, passive sensors or will try to emit on commercial-based navigation sets that almost all escorts carry. Most shipboard choppers carry some form of surface search radar and a datalink which can allow for local coverage without the parent vessel radiating and giving its position and identity away cheaply.

IF you can force the ship to emit on its main radars, and that is a big IF, then the ARM angle comes in to play and it is definitely a viable method of attack. The new concept of high endurance rotary UAV’s capable of lofting lightweight search radars for 8 hour missions would be the answer to that issue. Also reliance on passive EW detects to track and engage does allow the opposition to lead you a merry dance with decoys if they are a bit canny with it!.

I’ve pointed this out before but back in the early days of HARM that’s exactly the idea they had in mind. Conceptual artwork showed them attacking a Kresta II cruiser with HARM. Basically clean off the antennas with HARM and follow up with PGMs. It would be relatively trivial for a carrier airwing to overwelm even a Kirov (that worked) that way. Four HARMs per aircraft is pretty standard even back in the Corsair II days.

I guess EO/IIR cameras and/or MMW radars with smart software and a ship database for terminal target point correction will be standard quite soon. Then you can use a combination of onboard active and passive sensors and offboard data to acquire the target from afar, and the terminal precision guidance to hit e.g. the bridge or any other vital section.

You don’t even have to target the FCR! If you’re homing on an air search radar, for example, a decent warhead will likely damage all sorts of things sticking out up there, which will usually include the FCR as well. Phased arrays placed on the superstructure will likely be better off, however. But an ARM pointed at one of those will cause a lot of other problems like damaging the superstructure and potentially injuring critical crew members.