Soft kill BMD

[lastdingo]

I am confused about why EVERY discussion of BMD is all about intercepting the missile or a warhead with another missile or by laser.
It's understandable for protection of stationary ground targets, but I don't get it for mobile ships.

Soft kill (decoys) proved to be extremely successful against radar-guided anti-ship missiles (actually more so than hard kill).


The alternatives:

1) Jam the threat radar, including from offboard jammer

2) Chaff / Pandara fog to conceal the ship, add additional radar contacts, conceal even the wake and bow wave out to sufficient distances

3) multispectral smoke and aerosols to conceal the ship, add additional places where it might be

4) receive early warning, turn by 90° to 180° at flank speed. One turn by 90° reduced speed to 1/2 of top speed and this can be sustained except if you have some extremely agile ship. So a typical warship would get away from any predictable impact point at about 15 kts ~ 8 m/s - IMO enough to avoid a direct hit by a non-cluster warhead

5) avoid getting shot at by jamming OTH radar, jamming / dazzling / destroying satellites, jamming data downlink of satellites if they need relay satellites for comms

6) add decoy ships of lesser value to the convoy


I understand that the Americans obsess about BMD because of their precious CVNs, but I don't get why other Western navies should care. Hard kill BMD is easily defeated via attrition and incredibly expensive in munitions and ship requirements (giant radar, especially if you do it American-style and want 4 radar antannas staring 360° instead of just one rotatable low-mounted radar for BMD).

 

[Scott Kenny]

I am confused about why EVERY discussion of BMD is all about intercepting the missile or a warhead with another missile or by laser.
It's understandable for protection of stationary ground targets, but I don't get it for mobile ships.

Mostly because 90+% of the discussion of BMD has been protecting targets on land from unguided incoming.

Soft Kill doesn't work against a dumb rock dropping on your position, that dumb rock is going to hit the ground regardless of what you do. The only way to stop the impact is to stop the rock before it hits you.

It's a whole different conversation when you are in a mobile target.

I understand that the Americans obsess about BMD because of their precious CVNs, but I don't get why other Western navies should care.

Because antiship ballistics were in use during the Red Sea Turkey Shoot. Which means that any bunch of terrorists could have them.

Not to mention that a whole lot of the things Europe needs have to flow through the Red Sea, so protecting that flow of trade requires standing where idiots like to throw anitship ballistics at cargo ships.

Hard kill BMD is easily defeated via attrition and incredibly expensive in munitions and ship requirements (giant radar, especially if you do it American-style and want 4 radar antannas staring 360° instead of just one rotatable low-mounted radar for BMD).

The USN is assuming that you will not know where the missiles will come from, which means you need staring 360. The smallest possible staring radar set is the 3x9RMA SPY6.

A single COBRA JUDY is not necessarily a small array.

 

[cccgong]

I am confused about why EVERY discussion of BMD is all about intercepting the missile or a warhead with another missile or by laser.
It's understandable for protection of stationary ground targets, but I don't get it for mobile ships.

Soft kill (decoys) proved to be extremely successful against radar-guided anti-ship missiles (actually more so than hard kill).


The alternatives:

1) Jam the threat radar, including from offboard jammer

2) Chaff / Pandara fog to conceal the ship, add additional radar contacts, conceal even the wake and bow wave out to sufficient distances

3) multispectral smoke and aerosols to conceal the ship, add additional places where it might be

4) receive early warning, turn by 90° to 180° at flank speed. One turn by 90° reduced speed to 1/2 of top speed and this can be sustained except if you have some extremely agile ship. So a typical warship would get away from any predictable impact point at about 15 kts ~ 8 m/s - IMO enough to avoid a direct hit by a non-cluster warhead

5) avoid getting shot at by jamming OTH radar, jamming / dazzling / destroying satellites, jamming data downlink of satellites if they need relay satellites for comms

6) add decoy ships of lesser value to the convoy


I understand that the Americans obsess about BMD because of their precious CVNs, but I don't get why other Western navies should care. Hard kill BMD is easily defeated via attrition and incredibly expensive in munitions and ship requirements (giant radar, especially if you do it American-style and want 4 radar antannas staring 360° instead of just one rotatable low-mounted radar for BMD).

Soft kill worked very well vs old ASM due to anemic compute/sensors back in the day. It'll work much worse now. It's also why flares are useless vs imaging IR missiles and even DIRCM is very hard as unless sensor is fully saturated it can fin the centroid of the DIRCM and still get useful guidance information.

Also the approach geometry played a huge role. You can put up a wall of obscurant up between you and the thread and hide behind it as it's not approaching from above. But that's not how BM's work.

1/2/3) The good ASBM have EO + radar so that doesn't work. They also recieve targeting data from sats. Steep incoming geometry means fog/chaff doesn't work very well (this is very different from cruise missiles which greatly reduces effectiveness of obscurents) + onboard processing means you can find centroids of fog/chaff and any brief partial visibility (think 1/120s) means it reaccquires the target due to better processing. Also chaff doesn't really work well vs higher frequencies.

4) The BM can pull way may G's than your ship can and has onboard sensors/targeting.

5) You start doing this, they do this to all your sats too then we have kesseler syndrome. Also the Chiense have 300+ mil + dual use civilian sats, good luck doing that to enough to degrade their capabilites substanially. They have enough to have 20 minute coverage of the Pacific with SAR sats and 15 minute coverage with EO. Combined this likley means 10 minute coverage.

Then add in "neutral" or false flagged trawelers/cargo ships providing data to the Chineses along with UUV and USV.

6) Decoy ships are very expensive and need to look visually identical or very similar to the valuable ships.

 

[Scott Kenny]

4) The BM can pull way may G's than your ship can and has onboard sensors/targeting.

As I read it, that option was to get out from under the BM footprint. Though that depends entirely on just how maneuverable the MaRV is. A 30kt ship can displace 15nmi in half an hour, after all.

 

[cccgong]

As I read it, that option was to get out from under the BM footprint. Though that depends entirely on just how maneuverable the MaRV is. A 30kt ship can displace 15nmi in half an hour, after all.

That's not going to happen with BM flight times. You're looking at 10-15 minute flight time. So you can move 7.5nmi, and that assumes you know exactly when it launches that it's headed at you. You won't any idea where it's going until 2ish minutes after launch, and that's if you're observing the launcher and missile the whole time. This is also supposing MARVs not hypersonic in which case you have to watch even longer.

Realistically there's some latency on both, so you likley don't know to start moving until there's 2-3 minutes left before impact. Then you need to start moving and can maybe displace 1nm, and the missiles and their trajectories would have been designed with enough manuvvering budget that simple displacement wouldn't work.

Even if you could displace when launches start they'd get mid course targeting updates from sats so the ship's displacement would get effectively reset mulitple times through the course of the missile's flight

 

[Scott Kenny]

That's not going to happen with BM flight times. You're looking at 10-15 minute flight time. So you can move 7.5nmi, and that assumes you know exactly when it launches that it's headed at you. You won't any idea where it's going until 2ish minutes after launch, and that's if you're observing the launcher and missile the whole time. This is also supposing MARVs not hypersonic in which case you have to watch even longer.

I'm assuming that DSP/et sim satellites could handle the watching for alerts. Every ship does a bootlegger turn as soon as the DSP launch detected flag goes off.

Realistically there's some latency on both, so you likley don't know to start moving until there's 2-3 minutes left before impact. Then you need to start moving and can maybe displace 1nm, and the missiles and their trajectories would have been designed with enough manuvvering budget that simple displacement wouldn't work.

How many gees is 2km in 2 minutes at 3km/sec velocity?

Even if you could displace when launches start they'd get mid course targeting updates from sats so the ship's displacement would get effectively reset mulitple times through the course of the missile's flight

That gets into where your RV actually separates from the bus. Most BMs have been focusing on popping the RVs as early as possible to get the RVs into as large a cloud as possible.

 

[cccgong]

I'm assuming that DSP/et sim satellites could handle the watching for alerts. Every ship does a bootlegger turn as soon as the DSP launch detected flag goes off.



How many gees is 2km in 2 minutes at 3km/sec velocity?



That gets into where your RV actually separates from the bus. Most BMs have been focusing on popping the RVs as early as possible to get the RVs into as large a cloud as possible.

You realize that some of the ASBM/hypersonics have ranges of 3000km? Even their short range ones have ~1000km range. You're going to be having most of the ships in theatre going to flank every couple hours.

The second is a vacuous question, without an ton of other variables.

No one is doing boost phase intercept of any BM, also ASBM aren't MIRVed so there's no bus threshold that you are thinking about let alone hypersonics.

 

[Scott Kenny]

You realize that some of the ASBM/hypersonics have ranges of 3000km? Even their short range ones have ~1000km range. You're going to be having most of the ships in theatre going to flank every couple hours.

Yeah, so it's like every ship has a new captain. Captain Tammen would randomly jump into control and kick Georgia BN into Ahead Flank because he could for his entire first patrol.

The second is a vacuous question, without an ton of other variables.

I thought that was sufficient data? Though simple formula implies 0.0283 gee, which iirc is well within Pershing II MARV limits.

No one is doing boost phase intercept of any BM, also ASBM aren't MIRVed so there's no bus threshold that you are thinking about let alone hypersonics.

Popping the RVs as soon as the missile is clear of the atmosphere and/or done boosting is not boost-phase interception, it's creating the largest possible cloud of decoys etc for when the missile hits atmosphere.

 

[MadRat]

The USN is assuming that you will not know where the missiles will come from, which means you need staring 360. The smallest possible staring radar set is the 3x9RMA SPY6.

SPY-6 can stare out 120 degrees from a panel but the quality of the information is greatly diminished at the edges. A 3-sided 3x3 RMA structure may be more sensitive than a 4-sided 2x2 array, but I would think they can make 2x3 arrays work, too. And why not 1x6? European frigates are using much snaller arrays in four directions for BMD. Honestly, the physics would suggest you can run multi-RMA strings of 1x wide panel arrangements to build quite a granular picture for the volume of airspace, too. I question the insistence of sticking all your panels into large single-direction groups on every ship.

The greater the distance from the ship, the more time you have to scan and search. The closer to the ship the more directions you want panels because you have an exponentially shorter time to scan as distance shrinks. So to me it makes sense to use long-arrays for distance; and more numerous, distributed arrays for the proximity. Longer, thinner arrays work magic on airborne platforms. I see zero reason the same does not work on ships capable of much greater power generation. So to me these massive but 'flawed by design' 3-side array arrangements are a bit of a gold-plated solution. Maybe - just maybe - we would be better off with a solution where less expensive ships cooperate to scan together with less expensive array strings. Putting all that load on one ship has reached its end imho.

 

[cccgong]

Yeah, so it's like every ship has a new captain. Captain Tammen would randomly jump into control and kick Georgia BN into Ahead Flank because he could for his entire first patrol.



I thought that was sufficient data? Though simple formula implies 0.0283 gee, which iirc is well within Pershing II MARV limits.



Popping the RVs as soon as the missile is clear of the atmosphere and/or done boosting is not boost-phase interception, it's creating the largest possible cloud of decoys etc for when the missile hits atmosphere.

No it depends what direction the target is relative to the trajectory of the BM, your altitude, etc

SPY-6 can stare out 120 degrees from a panel but the quality of the information is greatly diminished at the edges. A 3-sided 3x3 RMA structure may be more sensitive than a 4-sided 2x2 array, but I would think they can make 2x3 arrays work, too. And why not 1x6? European frigates are using much snaller arrays in four directions for BMD. Honestly, the physics would suggest you can run multi-RMA strings of 1x wide panel arrangements to build quite a granular picture for the volume of airspace, too. I question the insistence of sticking all your panels into large single-direction groups on every ship.

The greater the distance from the ship, the more time you have to scan and search. The closer to the ship the more directions you want panels because you have an exponentially shorter time to scan as distance shrinks. So to me it makes sense to use long-arrays for distance; and more numerous, distributed arrays for the proximity. Longer, thinner arrays work magic on airborne platforms. I see zero reason the same does not work on ships capable of much greater power generation. So to me these massive but 'flawed by design' 3-side array arrangements are a bit of a gold-plated solution. Maybe - just maybe - we would be better off with a solution where less expensive ships cooperate to scan together with less expensive array strings. Putting all that load on one ship has reached its end imho.

The euros are building to a much less severe threat. Also 1x6 means you have very low resolution in one direction. Generally if you are talking about something in a ballistic trajectory as you have the geometry to detect it far away, you don't care about coverage quality. You just need to detect it at range and then you have time 10-20s to orienent yourself such that your lobes line up properlly with the target to get a firing solution. If you're dealing with hypesonics you need both great resolution/senstivity and coverage as you don't have time to reorientate due to geometry.

Airborne systems use long thin arrays as you can easily have a long array along the length of the aircraft body. You can't exactly make a large square array on an aircraft that's as tall as it is long

 

[lastdingo]

Soft kill worked very well vs old ASM due to anemic compute/sensors back in the day. It'll work much worse now. It's also why flares are useless vs imaging IR missiles and even DIRCM is very hard as unless sensor is fully saturated it can fin the centroid of the DIRCM and still get useful guidance information.

Also the approach geometry played a huge role. You can put up a wall of obscurant up between you and the thread and hide behind it as it's not approaching from above. But that's not how BM's work.

1/2/3) The good ASBM have EO + radar so that doesn't work. They also recieve targeting data from sats. Steep incoming geometry means fog/chaff doesn't work very well (this is very different from cruise missiles which greatly reduces effectiveness of obscurents) + onboard processing means you can find centroids of fog/chaff and any brief partial visibility (think 1/120s) means it reaccquires the target due to better processing. Also chaff doesn't really work well vs higher frequencies.

4) The BM can pull way may G's than your ship can and has onboard sensors/targeting.

5) You start doing this, they do this to all your sats too then we have kesseler syndrome. Also the Chiense have 300+ mil + dual use civilian sats, good luck doing that to enough to degrade their capabilites substanially. They have enough to have 20 minute coverage of the Pacific with SAR sats and 15 minute coverage with EO. Combined this likley means 10 minute coverage.

Then add in "neutral" or false flagged trawelers/cargo ships providing data to the Chineses along with UUV and USV.

6) Decoy ships are very expensive and need to look visually identical or very similar to the valuable ships.

1,2,3)
I'm not talking flares, I'm talking RP smoke and IR SMK aerosols

View: https://youtu.be/rQ4r2AF6XGw?si=_ayZg2Kdkrh4A2tm&t=21

obscuration, including obscuration of empty sea to give false probable contacts

Radar can detect the ship (potentially, but in direct approach not likely to be imaging), its bow wave pattern and possibly (dunno) its wake. All of this can be messed with by jammers, offboard jammers, pandara fog, chaff. To be absolutely clear; I don't mean 1970's chaff near the water surface only. It can be released as clouds above the ship as well.
Btw, corner reflectors should suffice to mess with wave pattern recognition and it's not too hard to have corner reflectors at air density, floating in the air. Moreover, there are now DRFM decoy jammers mounted in quadcopters (Rheinmetall 3DDS).


Any satellite would have no better data picture short before impact other than maybe imaging radar quality (if not messed with) when a missile seeker without lateral movement may not have it.

4) evasive manoeuvres is about deviating from a predictable course, not about dodging a missile that can sense the ship

5) Satellites on most (and all low) orbits visit all places. This means sooner or later they overfly any single battery of very powerful surface-based lasers. https://ui.adsabs.harvard.edu/abs/2024SPIE13201E..0GO/abstract
SAR sats should be highly susceptible to directional EMP attack (with all warhead fragments falling down instead of entering orbits).

6) Decoy ships don't need to approximate the shape of the real target if all they need to do is to create the same bow wave (speed-dependent) and wake. Moreover, even a NEW cargo ship costs on average about 100 million $. You could literally have multiples of those as decoys instead of upping one AAW frigate to a BMD-rated DDG. And they could double as replenishment ships, launch decoys, absorb without sinking lots of missiles and even torpedoes (VLCC supertanker ~ 130 million $, imagine that filled with closed cell foam and with auxiliary drives that keep it liming after the normal screws and shafts are gone.)

 

[Big_Zukini]

Soft kill and methods other than strictly hard kill are indeed employed against BMs, but these tend to be on the more classified end, on top of being more tailored to specific threats, so they're just not discussed much.

 

[Scott Kenny]

SPY-6 can stare out 120 degrees from a panel but the quality of the information is greatly diminished at the edges. A 3-sided 3x3 RMA structure may be more sensitive than a 4-sided 2x2 array, but I would think they can make 2x3 arrays work, too.

I think the 3x9 RMA is intended to be the minimum capability. I suspect that the 120deg panels are filling in the information quality via the neighboring array.

And why not 1x6? European frigates are using much snaller arrays in four directions for BMD. Honestly, the physics would suggest you can run multi-RMA strings of 1x wide panel arrangements to build quite a granular picture for the volume of airspace, too. I question the insistence of sticking all your panels into large single-direction groups on every ship.

As I understand it, the 1x wide has issues with beam forming vertically. Even with square or rectangular RMAs or blocks of TRMs, the closer the overall array is to circular the better the performance.

So, 1x2 might be fine, especially with rectangular RMAs like SPY6. But 1x4 or 1x6 is bad for vertical search.