054/A FFG Thread II

[W20]

But a Frigate 054 has a better defense against a subsonic anti-ship missile than a Destroyer against a YJ-12

 

[nlalyst]

Its called Track Via Missile for something and the reason why TVM exists in the first place is because Command Guidance alone can be inaccurate for terminal homing. While the distances of the target and the missile can be known by the ground radar, unfortunately there is still a variance and error, and the farther it goes, the greater it gets. That's one reason why CG is literally gone from longer ranged SAMs and still exists in some very close ranged SAMs like a Tor or a Croatale. The whole point of TVM is that the ground radar is not trusted for its data, and whether you want to refine existing data or to not trust the ground station data, its still a bistatic application. Let me remind you that the reason why you have variance and error with speed measurement in the first place is that what you would expect for medium to low PRF from the ground station against a target over long range. The higher the PRF the more accurate it gets; when you reach infinite PRF, its literally Continuous Wave.

Here you go again with completely made up claims. Please read up on how TVM works. It is command guidance through and through.

Anyone who's read up a bit on how radars work knows that maximum radar range accuracy is significantly better than range resolution. The latter is mostly a function of radar bandwidth, and even S-band military PD radars with pulse compression can have resolutions less than 1m, let alone C-band or X-band. That's more than enough resolution to command guide a missile to target. In practice, the real limitation is the size of the range cells, which was at least in part bottlenecked by memory/CPU (for 80/90s era systems, not anymore). The greater problem is angular resolution to guide the missile, and that's where TVM comes in.

Going back to the SPG-51. The fact that you have a monopulse CWI means the CWI can track the target on its own. In other words the C-band PD doesn't need to operate to track for the monopulse CWI which can track a target on its own (minus range information). As a matter of fact, simultaneous PC and CWI operation on the same antenna imposes quite some interference when you have both circuits in transmit and receive. The reason for having a separate PD and CWI feed is more likely because one is a C-band feed and the other is an X-band feed. The horns for each has to be sized and separated appropriately by the physical wavelength and can't be used for one or the other. If the PD and CW are both X-band, they can time share between the same feed.

The tracking radar is in C-band. The CWI is in X-band.

P STT or PD STT For AWG 9 (F-14 radar for you folks) is PD to support actively guided Phoenix missile. If you are using Sparrows on SARH with P STT or PD STT, its really on CW and not PD. The label is retained for convenience.

Explain how "its really on CW" works for Sparrow AIM-7M that has only a PD semi-active seeker?

As for Skolnik, the Brimstone and the RBS-15 are already real world examples that he is wrong. These are actively guided missiles that use FMCW while sharing single antenna for both transmit and receive.

That's a good one. That Skolnik source was published in 1990, so it's no longer up to date with newer seekers.

 

[Gloire_bb]

The first jet fighter to exhibit low RCS qualities, like in not appearing in radar until it is close enough, was the MiG-21 during the Vietnam War. This discovery was put down by a scientist in the Soviet Union, is the first ever paper to describe the use of shaping to reduce radar reflection.

It wasn't the first, nor it was something unexpected. Like literally, plane development included RCS measurement since 1940-1950s, and these planes were tracked by friendly radars all the time. The idea that they only SUDDENLY NOTICED that Mig is annoyingly blinky from the front from captured American pilots is a myth.
RCS studies date back to the very eve of the jet era and beyond - it was very quickly noticed, that the radar echo of different objects doesn't correspond with their size and that same objects reflect very differently in different bands. It was noticed literally everywhere where they worked on early warning radars during ww2.
Smaller RCS was a known advantage since forever, and by the 1960s was a well-understood advantage of smaller a/c with a less exposed engine over larger ones. The early US attempts to actually design a true stealth plane actually happened at the exact same time. They simply weren't possible w/o sufficient computing power and a proper model - and that only became available slightly later (Ufimtsev enters the chat).

Spoiler: Model 226

Remember this pretty bird and her results?

If you want examples, just compare the shape of the Oniks and the YJ-12 to things like the Harpoon, YJ-83, Tomahawk or the YJ-62.

Example of stealthy supersonic ASCM. Onyx certainly isn't one, YJ-12 isn't either. LACM will do as well.

You don't have to explain basic principles of stealth - I guess veteran forum members know them by heart. The crux of the problem is that Harpoon(Kh-35) is operationally less detectable than Onyx, stealth or not. And even in the 2020s is troublesome enough, many decades after first coming to the scene.
Making radome angled instead of round doesn't magically make you sneaky beyond commercial press releases. Stealth is a lot of work, and being stealth and supersonic at the same time is many times harder still. For modern* ASCM applications, where we're limited by (1)nature of the use of the weapon, (2)price of single-use saturation weapon, (3)size limitations - it's either one or another.

*it would've worked with old Soviet fighter-sized monsters - and no wonder, Soviets actually worked on it. But Soviet Navy is gone.

As for datalinks, if you are directional you would have to be using a phase array at least on the missile and the ground station.

Don't remember talking about Ground station.

I don't understand what you mean by an LRASM like missile searching down low. Searching down low with any drone or missile is straight out inefficient and requires far greater time and fuel to accomplish. Stealth is a zero factor to this.

Searching down low ensures you remain below the horizon., thus ensuring at worst that you and target will have a chance to see each other at the same time*. Simple as that. The efficiency of turbofan on an airframe with a lot of lift(lifting body+high ratio wings) + modern computers allows complicated search patterns, and even at subsonic speed missiles can explore a lot.
This is a widely promoted advantage, because, frankly speaking, it's quite obvious.
*but (1)missile is smaller than the ship, and (2)search pattern will be necessary only if no targets use radar (LRASM is a dual-band, after all).

I don't even know why you keep bringing in the LRASM in the first place, when the original premise is a conventional subsonic missile, like the YJ-83, versus a supersonic missile like the YJ-12. Or to be precise, the YJ-83 vs. the YJ-12. What's the advantage of using the YJ-83 over the YJ-12?

LRASM is a convenient and reasonably well-understood go-to example for a modern stealthy ASCM.
We know almost nothing about the new YJ-83 with double band seeker, other than its existence and what appears to be /stealthier/ shaping.
Since basing argument on assumptions about largely unknown missile is inefficient - it's way more convenient to base an argument on a better-known quantity. LRASM in itself is indeed a very different weapon - which, frankly speaking, doesn't make too much sense aboard the ship either. But it doesn't affect its value as a reference point.
Possible advantages of YJ-83(with new seeker) over YJ-12 are:
1. Unification of secondary weapon between all frigate units. And we're building a normal frigate.
2. Substantially(many times) smaller size and weight - affecting both ship design and handling, including handling at sea.
3. Price (including readiness aspect - cheaper, numerous missile allows more actual, not electronic launches=better trained crews).
4. Better suitability for a typical firing situation of a ship-mounted ASCM (sneakier, much lower minimal range) in SCS/ECS.
5. Much better capability against smaller targets, which are abundant in seas around China.
6. Far better ability to identify targets in a target-rich theater. Remember the 2008 Mirage debacle? Miracle away from a war crime.
7. Good enough against the majority of targets (4-missile salvo will likely go though even against targets with AA)
8. Much better ECM resistance.

That's enough?

 

[ougoah]

The NSM weighs half as much as the latest YJ-83 variants and has superior range. The air launched variant of YJ-83, with a claimed range of 230 km fares even worse versus JSM (air-launched variant of NSM) and its range of 555+ km. That's half the weight for over twice the range in favor of JSM.


LRASM is 1/3 the weight of YJ-12 and has over twice the range. That's quite a significant difference for an air-launched missile.

Like I said, China has a huge range of anti ship missiles. The closest "equivalent" to NSM is a modernised YJ-83 which btw we don't know the true weight of. The warhead is supposed to be around 70% or so heavier than the NSM's. Their ship/land launched variants have pretty much the same reported range. The air launched NSM is longer ranged by a greater margin. It's also a considerably newer design and certainly much more expensive and probably more complex to build, involving much more expensive materials compared to the "build me 1000 quickly YJ-83s". It's comparing a FN2000 with an AK-47. Both are effective and have a place in their respective roles in their respective militaries.

The YJ-83 has a place in Chinese arsenal. It is useful enough for pretty much every circumstance up to and including shooting at peer or superior adversaries like USN. It would require at least one interceptor from USN like a YJ-12 would require at least one interceptor.

NSM on being unimpressive isn't going to be refuted by comparing it with a 1990s missile design. It could potentially be around half the weight of the YJ-83 but it is also probably more than twice the cost and production rate and cost? who knows.

NSM as a piece of anti-ship missile is unimpressive considering how HGV weapons and AShBM are also anti-ship missiles. They are certainly in a different class but thinking NSM is impressive even if it achieves 1990s range with half the weight is like thinking a 3rd gen fighter is cool and impressive in an era of 5th gen proliferation just because the new 3rd gen fighter is able to offer 3rd gen capability with half the weight or the same weight and twice the usual range.

We don't know the exact true weight of YJ-83. It is slightly larger than NSM and most likely has a significantly larger and heavier warhead than NSM. The NSM is a good missile like I said. It's just unimpressive like the YJ-83 is unimpressive but both are clearly useful.

 

[plawolf]

I actually think pure stealth subsonic AShMs like NSM are a suboptimal design.

Remember that Stealth isn’t absolute. Get close enough and radar power will overcome stealth. Which is the core issue with stealthy subsonic AShMs like the NSM. They need to go straight at targets with the biggest and most powerful mobile radars on earth, and they need to close to zero distance. As such, detecting is inevitable, with the real question being at what distance.

Depending on what that distance is, NSM stealth could range from really useful to functionally worthless.

I think any Chinese stealth AShM will be based around the YJ18, or something along those lines, which will use stealth to get close and then rely on speed for last stage penetration based on speed, thereby giving it the best of both worlds.

 

[AndrewS]

In the debate of subsonics vs supersonics, I don’t think either are inherently better than the other. Subsonics provide vastly greater range for the same weight. Supersonics provide superior time to target and a theoretically higher chance of evading ship borne defenses. Although, that’s only if they aren’t detected cruising at 20+ km and engaged by long range SAMs.

As for PLAN vs USN, the comparison cannot be easily made since the the two navies have different ASuW doctrines. Currently, the USN emphasizes aerial platforms for anti-shipping. Its ships are comparatively much worse armed than PLAN’s. Because of the emphasis on aerial platforms, they invested in smaller missiles that can be carried by fighters. The aerial launch platform provides range extension, while the missiles offer attack possibility at stand off range.

The USN has already decided that using aerial platforms for anti-shipping is a losing proposition.
Read some of the reports published by the CSBA.
We've also had various discussions on these sorts of reports on the forum throughout the years.

Weight is not the key criteria for anti-ship missiles.
It only matters for the USN because they have to use expensive bombers and fighter jets to deliver missiles.

If you launch the missiles from land, the weight doesn't matter.
The launcher vehicle is just a cheap truck.
The cost and performance of the missile is more important.

While subsonics may be an easier target for the defense on an individual case, when carried by air platforms, they can saturate the enemy with up to 10 times as many missiles compared to equivalent range supersonics. Such swarming may be enough to deplete defense missile cells or overwhelm the available defensive firepower.

Saturation attacks can work. But look at the geography of the Western Pacific.

Over the Taiwan Straits, I'd expect to see at least a thousand SAMs covering the area. That's from a mix of destroyers, frigates and land-based SAMs

In addition, there would be AWACS and numerous fighter jets shooting down hundreds of LRASMs.
LRASMs are slow and you can't get away from that.

You would be far better off with a smaller number of hypersonic missiles that can avoid fighter jets and the majority of SAM systems.

 

[blindsight]

And another factor here, if you think forward, your AShM may have to penetrate the future laser-based defense systems. I don't feel subsonic missiles have much chance. On the other hand, faster your AShM, more difficult for the laser system to totally destroy it, especially for the last stage. As long as it hits the ship, even if the warhead has been disabled, it'll still cost a lot of damage due to its residual kinetic energy.

 

[banjex]

Didn't know this was a missile thread.

 

[Gloire_bb]

NSM as a piece of anti-ship missile is unimpressive considering how HGV weapons and AShBM are also anti-ship missiles. They are certainly in a different class but thinking NSM is impressive even if it achieves 1990s range with half the weight is like thinking a 3rd gen fighter is cool and impressive in an era of 5th gen proliferation just because the new 3rd gen fighter is able to offer 3rd gen capability with half the weight or the same weight and twice the usual range.

HGV and AShBM won't really be useful against, for example, VPN Corvette intermixed with various local craft. And these are very dangerous ships.
Light ASCM is meant to be a very universal weapon. Universal secondary weapon on a universal warship (which Frigate is).

Or, say, if maritime militia gives you targeting data on radio-silent LCS/USV trying to be sneaky around 1st Chain - YJ-83 salvo can catch it completely off guard, and the fastest things to react - countermeasures, not weapons - may not be useful against two-band seeker working on a convenient platform.
Supersonic launches are way more visible, hypersonics and AShBMs will warn the whole region about the launch, not just the target. While giving everyone the exact, true, and up-to-date location of the launcher at the same time.

In the end - key consideration here is that we are not discussing missiles per se. Supersonic missiles are cool. Hypersonics even cooler(and expensive, lol).
We're discussing a weapon for a mass-produced frigate, which has to be able to engage all sorts of targets of opportunity, with as little consideration for remaining missile count, all that - while taking as little space as possible. This is a very special sweet spot for a weapon, and sub-1t subsonic missiles fit it very well.

 

[ougoah]

HGV and AShBM won't really be useful against, for example, VPN Corvette intermixed with various local craft. And these are very dangerous ships.
Light ASCM is meant to be a very universal weapon. Universal secondary weapon on a universal warship (which Frigate is).

Or, say, if maritime militia gives you targeting data on radio-silent LCS/USV trying to be sneaky around 1st Chain - YJ-83 salvo can catch it completely off guard, and the fastest things to react - countermeasures, not weapons - may not be useful against two-band seeker working on a convenient platform.
Supersonic launches are way more visible, hypersonics and AShBMs will warn the whole region about the launch, not just the target. While giving everyone the exact, true, and up-to-date location of the launcher at the same time.

In the end - key consideration here is that we are not discussing missiles per se. Supersonic missiles are cool. Hypersonics even cooler(and expensive, lol).
We're discussing a weapon for a mass-produced frigate, which has to be able to engage all sorts of targets of opportunity, with as little consideration for remaining missile count, all that - while taking as little space as possible. This is a very special sweet spot for a weapon, and sub-1t subsonic missiles fit it very well.

Which is why everything from KD-63 to YJ-18 have a place. I didn't suggest HGV and AShBM to be used on Corvettes. They are way too expensive and rare a resource to waste on those, particularly when they wouldn't be protected anywhere near as much as a carrier is protected.

My point is to say that all those weapons have a place in China's anti-shipping arsenal. LRASM equivalent seems to be missing and it is so simply because China as of now has no suitable airborne platform to carry them in large numbers. YJ series are mostly land, submarine or ship launched. There is no evidence a stealthy subsonic LRASM equivalent would be more useful to PLAN than YJ-18 already offers but without the need to spend resources and a decade to develop. It might however be something the PLA looks into for the next generation YJ-18 replacement as it fits the bill. As long as they can make it speed up supersonic and turn in the last few kilometers.

These sea skimming are quite stealthy anyway unless CAP can assist in spotting them and directing interceptors. Stealthiness is honestly of possibly limited value for the cost. It's difficult to say for sure but I'd much rather have HGV antiship missiles and focus on taking on the bigger targets - carriers first. Once those defenses are gone, swarm attacks and attrition is the only true certain way of sinking a fleet. Stealth missiles probably won't work against the USN but 10 times as many sea skimming supersonic ones will erode defenses far more. AShBM and HGVs for higher value and more well defended targets. The game is A2AD and 90% of the battle is subsurface and in the air. LRASM can allow China greater stand off range in case the air is much more heavily contested and there is no equivalent air launched of that volume and weight. Without the H-20 for LRASM type missiles, China has to go with HGVs and AShBM for that stand off range. YJ-18 of course too.