Surface vessel decoys and countermeasures

[Todjaeger]

Quoted posts start from here.

Off-topic but after reading your post, something occured to me. Most combatants in most navies - even smaller non-NATO ones - are fitted with chaff launchers to decoy missiles. But, are most LPDs, LSTs or even combatants in larger NATO [which also have chaff launchers] fitted with torpedo decoys? Granted, it depends on the circumstances but I think people tend to place too much emphasis on the threat posed by air, land and sub launched sea skimmers but surely sub launched heavyweight torpedos pose an even greater threat? Do we know if USN, RN and Marine Nationale carriers are fitted with torpedo decoys as insurance in case a sub gets past their escorts?

Also, do we know yet if the AWDs will be fitted with Nulka or another system?

On a related note to the question about torpedoe decoys, how effective are they against modern heavyweight torpedoes, realistically?

Given that many of the sub-launched heavyweight torpedoes have wire guidance from the sub for some distance, I would imagine that decoys might only be effective when the torpedoe is reliant on its own onboard guidance package.

What might work better are bubbling systems like Praire Masker, perhaps working in concert with a noisemaker and/or depth bomb.

-Cheers

I see your point but surely we can say that same about chaff vs Sea skimmers as there are many variables involved as to whether chaff will work against the seeker head of a particular missile when the missile goes in the terminal phase? Same I think goes with active jammers as to how effective they will be against sea skimmers, especialy given that certain missiles have home on jam stuff fitted [assuming of course they work as advertised].

Started a new thread to avoid hijacking the RAN thread.

With respect to the countermeasures discussion, my question about the realistic impact of an anti-torpedoe countermeasure was more about how often a heavyweight torpedoe is/would be fired against a surface vessel, and have the torpedoe be forced to rely upon its own onboard guidance package.

With many of the AShM's available out there, the expectation is that the missiles would be fired against OTH targets, beyond the detection and guidance capabilities of surface, subsurface or even aerial launch platforms. With that in mind, the anti-missile countermeasures need to defeat the guidance package of the inbound missile.

I also expect that countermeasures like chaff are more of a last ditch effort, since they would be used against incoming missiles which have leaked through an area air defence umbrella, and apart from the countermeasures, the only other hardkill systems possibly available would be CIWS. Active softkill systems like Nulka IMO are likely more capable, but again seem primarily intended as part of a final effort.

Against torpedoes the question still remains, how often would a heavyweight torpedoe be fired from a sub, when the range is further than the sub could provide guidance updates? If most surface vessel warshots are taken with guidance from a sub, then the surface vessel's countermeasures need to be able to disrupt/defeat not only the torpedoe's onboard guidance package, but also the sensors and combat data system of the attacking sub.

-Cheers

 

[STURM]

Thank you for opening a new thread to deal with my queries. I've always been interested in naval self-defence systems but I, admitedly, know little of the technologies involved.

With that in mind, the anti-missile countermeasures need to defeat the guidance package of the inbound missile.

And the only soft kill option is by means of chaff or an oboard active jammer, which may or may not be effective against that particular missile which may in turn be fitted with home on jam technology.

I also expect that countermeasures like chaff are more of a last ditch effort, since they would be used against incoming missiles which have leaked through an area air defence umbrella, and apart from the countermeasures, the only other hardkill systems possibly available would be CIWS. Active softkill systems like Nulka IMO are likely more capable, but again seem primarily intended as part of a final effort.

Chaff is indeed a last ditch effort for ships that are targeted by sea skimmers but lets face it, only a handful of navies have the luxury of being able to call or rely upon on a multi-tiered defence layer - from fighters or MPAs to deal with ships and subs before they can fire, to long and middle range surface to air missiles to deal with the missiles that get through. For most navies, chaff and guns - and if they're lucky to have missiles - are the main means of dealing with sea skimmers.

Correct me if I'm mistaken, but am I correct in saying that live tests have only been done against subsonic drones that were used to simulate sea skimmers and that only simulated computer based tests have been performed against supersonic sea skimmers? If that's the case, how do we know with any certainty that ESSM, Standard, Aster 30/15 and gun based CIWS can indeed deal with supersonic threats? The Indian Navy [IN] experience with Kashtan for me is a prime example of the importance of during realistic evaluations on systems rather than taking what the manufacturer claims at face value. During trials conducted in the Baltic, the IN discovered that Kashtan could not hit targets flying at a certain [low] altitude which was the complete opposite of what its manufacturer had been saying.

If most surface vessel warshots are taken with guidance from a sub, then the surface vessel's countermeasures need to be able to disrupt/defeat not only the torpedoe's onboard guidance package, but also the sensors and combat data system of the attacking sub.

Yes but short of actually destroying the launching platform how is it technically possible to defeat the torps guidance package, by what means?

All in all, I think the fact remains that although most ships are fitted with chaff launchers to deal with air threats, many are not fitted with torp decoys, when it can be argued that in a littoral enviroment, subs may pose a bigger threat. It probably boils down to funding issues.

 

[Olaf]

Might possible scenarios arise in littoral waters?

Assuming that torpedoes can maneuver outside the view of the sub's sensor systems, one could imagine a torpedo fired from a sub lurking at the bottom of a fjord arm, turning 90 degress upon exiting the fjord, then hitting a large surface combatant at the entrance to the main fjord.

However, I don't know whether the torpedoes are capable of this. If they are, then subs could also hide behind islets at the outer edges of archipelagoes and fire at large surface combatants that are several miles off shore.

 

[RobWilliams]

Correct me if I'm mistaken, but am I correct in saying that live tests have only been done against subsonic drones that were used to simulate sea skimmers and that only simulated computer based tests have been performed against supesonic sea skimmers? If that is the case, how do we know if with any certainty that ESSM, Standard, RAM, Aster 30/15 and gun based CIWS can indeed deal with supersonic threats?

Off the top of my head there has been a case of an Aster 30 (PAAMS) launched from a Horizon class 'frigate' from the MN successfully hitting a supersonic sea skimming Coyote drone in tests earlier this year

French Navy frigate successfully intercepts supersonic sea-skimming missile - Naval Technology

The French Navy has successfully completed the first aerial target live fire of the US Navy's GQM-163A Coyote Supersonic Sea Skimming Target (SSST), off the Ile du Levant coast, France.

During the trials, the French Navy's Horizon-class air defence frigate, Forbin successfully tracked the GQM-163A SSST and intercepted the Coyote target with an Aster 30 surface-to-air missile in flight.

The SST was launched form the Direction Generale de l'Armement's (DGA) missile test centre based on the Ile du Levant in the south of France.

...


The Coyote programme, managed by the Naval Air Systems Command (NAVAIR), has been designed to provide an SSST system to simulate high-speed anti-ship cruise missiles for fleet training and weapon systems research, development, tests and evaluation.

OSC-built Coyote target missile design integrates a four-inlet, solid-fuel ducted-rocket ramjet propulsion system into a compact missile airframe.

 

[STURM]

Thanks for the information Rob.

I'm very curious as to why Raytheon has not announced the results of similar tests they surely have conducted with Standard and ESSM.

 

[Todjaeger]

Keeping in mind that I am doing this from memory, and still operating under a sleep deficit due to events in my region, here goes...

Chaff is a softkill countermeasure, but so is Nulka. The crucial difference being how they achieve a softkill. Chaff is intended to create a 'cloud' if one will, of radar reflective material between the inbound missile and target ship. If things go as intended, the radar seeker in the AShM gets either no, or a significantly weaker radar return, because the 'cloud' disrupts and redirects the signal. This can cause the lock to break, so that the AShM seeker has to reacquire the ship, otherwise the missile flightpath can go harmlessly away from where the target is.

Nulka OTOH is an active softkill countermeasure, using seduction systems to spoof the AShM seeker into targeting the decoy instead of the ship.

With respect to high speed target drones, IIRC at one point the US was using ex-Soviet/Russian supersonic AShM's as target drones. Following the fall and break up of the USSR, there had been many such missiles available on the open market, and the purchase price was actually lower than the target drones being developed within the US to replicate the AShM flight profiles the US wished to test defences against. After a period of time, Russia did put a stop to practices which allowed the US to purchase high speed AShM. IIRC one of the things which the US learned from such test intercepts, was that a number of the smaller air defence systems (like Phalanx) were starting to be of limited viability. It was not so much that such systems could not achieve hits on the inbound missiles, but that the missiles already had so much KE that even if the missile broke apart in flight missile fragments would still strike and damage the vessel. This is why the calibre of some type weapons was increased (like the Millenium Gun) and others were given a longer engagement range (like ESSM).

As for how to counter the guidance package of an inbound torpedoe... Something could be put into the water between the target vessel and incoming torpedoe to generate sonar returns (like a noisemaker) and hope that the torpedoe is using a home on sound guidance. If the torpedoe head is actively pinging though, then a great deal of noise might need to be generated to damage the 'ears' or something needs to be in place in the water to otherwise disrupt how the return pings get back to the torpedoe, at least until the torpedoe is too far away from the target. Given that some heavyweight torpedoes have estimated ranges of 50 km depending on speeds I do not forsee a reliable way to stop a modern inbound torpedoe.

-Cheers

 

[kato]

I'm very curious as to why Raytheon has not announced the results of similar tests they surely have conducted with Standard and ESSM.

A Norwegian frigate supposedly shot down 6-out-of-6 GQM-163A using ESSM a couple years ago.

GQM-163A is considered too pricey for the USN to waste in regular fire-to-kill exercises. Especially since they're apparently actively modifying the system the last couple years to simulate high-speed high-diver targets such as ballistic anti-ship missiles and anti-ship cruise missiles with supersonic terminal stages.

 

[Bonza]

Correct me if I'm mistaken, but am I correct in saying that live tests have only been done against subsonic drones that were used to simulate sea skimmers and that only simulated computer based tests have been performed against supersonic sea skimmers?

There have definitely been live tests in the past involving supersonic sea-skimming drones simulating anti-ship missiles as there are a range of US drones specifically designed for this purpose, as Kato mentioned. If I remember correctly the USN has previously used converted Talos anti-air missiles (which are obviously supersonic, though I don't know about their flight profile or how it was changed) to simulate AShMs. I'm sure there are other systems that could quite feasibly be used in this role too.

I'm not sure what the balance is like between "live" and "live-fire" exercises (Kato mentioned a bit about that too), but it has definitely been done in the past.

 

[ASSAIL]

Towed decoys

I am so far out of date with the latest towed decoys, I'm back in the days of 2 steel bars rattling together to make white noise.
It seems the 2 most common current systems are the USN - AN SLQ-25A and C (RAN uses FEL SLQ-25C) and the RN Ultra Electronis SSTD Type 2170, which was co-developed with the USN before cost got in the way.

Can anyone expand on what is available apart from the usual net sources? Are they effective against smart heavyweight torps? Is there other developments etc, etc.

Cheers

 

[StobieWan]

On ESSM testing the Dept of Testing and Evaluation had this to say in 2005


"FOT&E-1 occurred in March 2005 on USS Momsen
(DDG 92) in accordance with a DOT&E-approved test
plan. Testing included a stream raid presentation of two
supersonic maneuvering targets. One of the targets failed in
flight, and ESSM capability against the other target was not
demonstrated."



http://www.dote.osd.mil/pub/reports/FY2005/pdf/navy/2005essm.pdf

This link here is a bit more upbeat however

Aegis Baseline 7 Tested Against Supersonic and Subsonic Anti-Ship Missiles


I guess the question is has it been demonstrated vs a manoeuvring supersonic target - Sea Dart and Sea Wolf were both tested vs supersonic sounding rockets in the 70's for instance, but I doubt either could handle a manoeuvring missile.

 

[STURM]

Thanks for the all feedback provided, much appreciated.

What was the official reason given by the Israeli Navy as to why INS Hanit was hit by an C-802 without its Phalanx even engaging the target? Was the ship's crew even aware that it had been 'painted' by a shore based radar and that it had been fired upon - or was it a case of the Phalanx being switched off, like the incident with USS Stark?

This link has some interesting bits in it.

http://www.navweaps.com/index_tech/tech-103.htm

 

[Blackshoe]

What was the official reason given by the Israeli Navy as to why INS Hanit was hit by an C-802 without its Phalanx even engaging the target? Was the ship's crew even aware that it had been 'painted' by a shore based radar and that it had been fired upon - or was it a case of the Phalanx being switched off, like the incident with USS Stark?

Information Dissemination: INS Hanit: Stories From the Sea (Part #1) The official reason was always that the crew was not expecting any ASCM attacks and had no air defense systems on. Thus, as your link notes, Phalanx doesn't work in the OFF position.

See also here. http://www.strategypage.com/militaryforums/36-22440/page2.aspx

 

[AegisFC]

And the only soft kill option is by means of chaff or an oboard active jammer, which may or may not be effective against that particular missile which may in turn be fitted with home on jam technology.

There are several goodies that can be launched out of a SRBOC launcher in addition to chaff and flares. Such as seduction and distraction rounds.
Basically a surface combatant can make a very confusing electronic picture for any attacker
Also when a ship is deployed to a particular region there are intelligence briefs for each watch section that includes intelligence on what the likely threats are and, based on what is known, how best to counter those potential threats.

Correct me if I'm mistaken, but am I correct in saying that live tests have only been done against subsonic drones that were used to simulate sea skimmers and that only simulated computer based tests have been performed against supersonic sea skimmers?

The USN has an old remote control Spru-can it regularly shoots several types of supersonic and subsonic sea skimmers at (well they aim behind it at a barge stacked with con-ex boxes, but they have missed the target and hit the test ship in the past) to test out ESSM, RAM, Nulka and several other point defense weapons with. It is called the Self Defense Test ship and the USN has had several of them.
I work with someone who commissioned one of the early DDG-51's and said during the precomissioning testing they did dozens of live firings against all kinds of flight profiles.

 

[ASSAIL]

Are there any ASW counter measure nerds out there? See my post #9

C'mon guys, I knew that ASW has taken a back seat since the end of the cold war but really:

 

[kato]

Current development over here the last couple years (since the Cold War) was focused on hardkill anti-torpedo measures for surface ships and submarines and softkill decoy arrays specifically for submarines, the latter of which have been successfully introduced.

Nixie is still standard as far as towed decoys go.

If you want something off net sources, try to find out who Finmeccanica WASS has sold their 5-inch rocket based torpedo decoy system, C310, to. Their website says it's currently in production, but you'll have to google a bit to find out for who they're selling to (and you'll only find the UAE - two launchers, three years ago... gee, starting a production line for that? ).

Some Polish group was working on a probably rather similar concept using ship-based mortars or blast projectors two years ago btw, if you're looking for something a bit more exotic.

 

[PCShogun]

Not my area of expertise and risk sounding stupid here, but something I have wondered about is:

If a submarine tracks a surface target while submerged, and guides the torpedo based on that passive sonar data. Why not fire depth charges to disrupt the track, preventing the submarine and or its torpedo from getting an exact lock on the target, sort of underwater chaff? I roiling explosion should last for quite awhile and disrupt passive sonar for a time. Like active sonar, every sub in the area is going to hear it, but you've already been fired on so whats the point in trying to not be heard at this point?

Also, why not a counter torpedo to intercept the incoming fish? Set to proximity detonate, it may cut the wire, activating the inbound torpedo early and out of range of its own seeker.

If its a missile, why not have a helo up with a radar enhancer on it to provide a moving decoy beneath it, and give the incoming missile another target to track on. Especially if fired from over the horizon, the missile may activate early and seeing multiple radar contacts pick the wrong one. Going to suck for the pilot though unless you figure out how to get the decoy to hover on its own once a missile locks onto it.

Sorry if this is stupid, just something I have wondered about.

 

[Bonza]

As far as a counter-torpedo goes, there's already some ongoing efforts to build something like this. If you have a look around online you should be able to find some information on "hard-kill" anti-torpedo systems. Not sure about the depth charge thing, I would have thought the primary problem with defeating an incoming torpedo is knowing it's there in the first place...

Regarding missile decoys, have a look at the Nulka launched decoy. This is a vertical launch anti-missile decoy that projects a radar image in a manner similar to what I think you're describing. There is a little bit of non-specific information about it online, and if I remember correctly some videos of Nulka launches on youtube.

Hope that helps.

 

[PCShogun]

Yes, its more than I knew before. Also nice to know I wasn't off the mark by much.

 

[Tico90]

I don't have any experience in the Navy, so don't take this as fact, and please correct me if I am wrong, but...

Standard "dumb" ASCMs can be pretty easily decoyed using chaff. However, newer, "smarter" cruise missiles incorporate systems to discern what is a decoy and what is a target. In a situation where that kind of missile was launched, it would seem like a good course of action would be...

1) Fire a Nulka. The Nulka is specifically designed to deal with more difficult threats -- apparently, it is designed to deal with missiles that incorporate "passive decoy rejection and active angular deflection electronic countermeasures rejection capabilities." It radiates a ship-like target (i.e. -- the target "looks" like a ship to a radar, not just like a large return), and flies in a ship-like manner, allowing it to appear like a ship. Also, because it is a repeater, it doesn't emit actual jamming signals (the signals emitted are designed to emulate those of the missile's radar), so the missile does not know it is being jammed, and so cannot "reject" the decoy as being interference/jamming.

2) Enter complete EMCON. Some missiles use anti-radiation homing to determine which return it is receiving is the actual target. Going into EMCON would prevent the missile from picking up any signals that might give away which radar return is the actual ship.

3) Fire infrared decoys over the ship. Some missiles use infrared and electro-optical homing to determine which return is the target. By sending up a wall of flares, the ship-like infrared signature would be hidden behind the massive blob-like signature of the flares, causing the imaging infrared seeker to determine that the ship itself was a decoy, because the infrared signature looks nothing like a ship. In a sense, this would be using the missile's own "smarts" against it -- since the IIR seeker looks for targets that look like ships, the ship can hide in plain sight by creating a signature that does not look like a ship. Also, the visual distortion caused by the flares would skew an electro-optical sensor by messing with the visual contrast that EO sensors use to find a target, making them unable to determine that the ship was a target.

4) Evasive maneuvers? If steps 1-3 work, the missile will "see" two targets that do not look at all like ships -- the Nulka will have a convincing radar signature and emissions signature, but will not have ship-like infrared or EO signatures. The ship will also have a ship-like radar signature, but the flares will prevent it from having a ship-like infrared or EO signature as well. Also, since the ship is in EMCON, any anti-radiation seeker would be unable to determine it to be a target. In this situation, some "smart" missiles plot a path directly between the two returns, in the hope that it will hit the target. By maneuvering, the ship can ensure that it is not in the region where the missile has pre-plotted its flight at the time that the missile passes by.

Again, I have no naval experience, and so I claim NO authority whatsoever on this topic, but that procedure would appear pretty effective in dealing with "smart" missiles. Can I get any feedback from you guys about whether or not what I'm talking about makes sense and would be effective?

Of course, if I'm talking complete nonsense, please feel free to tell me so.

 

[colay]

Another low-cost approach.. set off explosives underwater timed to throw up a wall of water in front of sea-skimmers. There is a video of a successful test of the concept conducted at the Aberdeen Proving Ground somewhere on the www. Obviously won't work against any pop-up maneuver though. . . Perhaps, it might have some application in anti-torpedo defense?

Water Barrier Ship Self Defense Lethality - Higdon - 2009 - Naval Engineers Journal - Wiley Online Library

The Naval Surface Warfare Center Dahlgren Division has investigated technology for the Office of Naval Research (ONR) that has the potential to be very effective in defending Navy platforms against high-speed, sea-skimming anti-ship cruise missiles (ASCMs). This technology uses a new kill mechanism, a wall of water, to provide a low cost, universal terminal defense system for Navy ships. The Water Barrier or wall of water is generated from the shallow detonation of multiple underwater explosive charges to protect the ship from attacking sea skimmers. This terminal defense concept can be employed to slow or stop debris and warhead fragments from missiles killed at short range to preclude significant damage to own ship. Furthermore, the Water Barrier would defeat the fuzing and structure of ASCMs that have penetrated the inner self-defense layer.