PLAN Anti-ship/surface missiles

nlalyst said:

There is no intentional bias in CMO. There are some understandable gaps in the database on PLA platforms because officially published data is very scarce.

I did the same test with an E-3C: it detected sea-skimming LRASMs at 17.6nm, just marginally better than KJ-2000.

Actually, CMO appears to hardly penalize radars at all against sea-skimmers. I suspect that real-life performance would be worse.

This is the whole point of a VLO cruise missile: get past enemy pickets and capitalize on surprise.

Click to expand...

A number of issues

1. A sea skimmer is still 10m above the sea state. A doppler filter should easily be able to pick it up.
We see this with the J-STARS and other AWACs which pick up virtually everything but then have to use a doppler to filter for moving targets.

2. In the absence of data, the CMO bias goes for US weapons systems and against Chinese ones, which I've seen mentioned previously. That applies to the LRASM as well, since it is a new weapon and it is in the interests of both the US Navy and the manufacturer to hype up the weapon.

3. Plus what about the detection range when an LRASM has to present a side or rear profile to an airborne radar.

4. If a defending frigate or destroyer decides to keep its radar on, it can't be surprised by an LRASM.
If an LRASM is detected at the radar/visual horizon, you're looking at a near 100% probability that it will be shot down by SAMs.
That is based on 4 engagement rounds with a 70% probability each time.

---

And finally, if LRASMs are as effective as you think, it means the US Navy is completely screwed once China fields its own long-range version of the LRASM.

The entire Western Pacific to the 2nd Island Chain (3000km to Guam) can be swept with a few long-range sino-LRASMs launched on a speculative basis. As per your view, US AWACs are useless are detecting LRASMs. So when sino-LRASMs inevitably find US ships, those ships have to light up their radars and broadcast their location.

If LRASMs were that effective, you can damn well bet that the Chinese military would have trucks launching masses of LRASMs.
After all, the Chinese military have developed the entire range of antiship missiles (subsonic/supersonic/hypersonic) in varying sizes and configurations.

The CBSA also has an estimate of $7M for a LRASM with a range of 3000km, which is cheap compared to the hypersonic missiles being developed in China.

styx said:

15 nm is about the radar horizon for 0 meters altitude, are you sure it's not a bug?

Click to expand...

The AEW platform was flying at 36 kft: its radar horizon against a target flying at 30 ft is 240 nm.

The result is quite consistent with what I got against F-35: It was detected by E-3C at 40nm. In CMO, F-35 has a RCS 20.5 times bigger than LRASM. Detection range decreases with the cubic root of RCS: 20.5^0.25 = 2.12, and 40/18= 2.22. I think there is always a small random factor at play, so that the actual detection ranges move by a little bit each time.

FairAndUnbiased said:

a shipborne active radar does not have propagation and multipath scatter problems because it can do 3 things:

1. directionally emit to avoid noisy regions

2. encode the radar signals with a pattern so that the received is tuned for that specific frequency and pattern and any distortion is known and compensated for

3. use a multistatic configuration with i.e. a helicopter emitter and the ship is passively listening

a passive RF seeker cannot do these things:

1. it must accept whatever RF signals are incoming and cannot disregard entire directions because the target might be in that direction

2. it doesn't know what the incoming signal looks like; it has the burden of processing the signal to remove the noise

3. it relies only on its own passive sensor

Click to expand...

Every radar can suffer from multipath propagation. What you described are mitigation methods, but that's shifting the goal post. Passive RF has its own mitigation methods.

As far as I understand it, LRASM uses passive RF to detect areas of interest to explore, and threats like AEW to avoid. I wonder if it can actually work as a PCL radar and whether that would be useful in this context?

AndrewS said:

2. In the absence of data, the CMO bias goes for US weapons systems and against Chinese ones, which I've seen mentioned previously. That applies to the LRASM as well, since it is a new weapon and it is in the interests of both the US Navy and the manufacturer to hype up the weapon.

Click to expand...

At least in CMO, it is not hyped up at all. LRASM's RCS is modelled as only 10-12 times less than the F-22. Plus its DECM and evasive maneuvers seem broken as the missiles get picked apart by 052Ds with almost 100% Pk. BTW, J-20 is the deadliest aircraft in CMO. I don't agree that there is a systemic bias against Chinese platforms.

AndrewS said:

---

And finally, if LRASMs are as effective as you think, it means the US Navy is completely screwed once China fields its own long-range version of the LRASM.

The entire Western Pacific to the 2nd Island Chain (3000km to Guam) can be swept with a few long-range sino-LRASMs launched on a speculative basis. As per your view, US AWACs are useless are detecting LRASMs. So when sino-LRASMs inevitably find US ships, those ships have to light up their radars and broadcast their location.

Click to expand...

LRASM type missiles will have a hard time finding targets that are under strict EMCON. Plus, I don't think the USN doctrine is to fire missiles blindly and hope they strike something. They will have to locate and track the target with some other assets first.

nlalyst said:

LRASM type missiles will have a hard time finding targets that are under strict EMCON. Plus, I don't think the USN doctrine is to fire missiles blindly and hope they strike something. They will have to locate and track the target with some other assets first.

Click to expand...

For example, the US could fire LRASMs and have them fly straight down the Taiwan Straits.
You really don't need any targeting because they will encounter large numbers of high-value ships on such a journey.

But the Taiwan Straits will be covered by AWACs, plus large numbers of shipborne SAMs.

So those LRASMs will likely be detected early and subject to at least 4 engagement rounds, which means a 99% chance of being shot down.

AndrewS said:

For example, the US could fire LRASMs and have them fly straight down the Taiwan Straits.
You really don't need any targeting because they will encounter large numbers of high-value ships on such a journey.

But the Taiwan Straits will be covered by AWACs, plus large numbers of shipborne SAMs.

So those LRASMs will likely be detected early and subject to at least 4 engagement rounds, which means a 99% chance of being shot down.

Click to expand...

No, not really. If they are to have a reasonable chance to defeat a SAG with Type 052Ds, they have to arrive synchronized and in large numbers. To do that, you need to have a very good idea where the SAG is before launch. Otherwise, the missiles will be dispersed and arrive out-of-sync in small numbers, therefore unlikely to overwhelm the enemy's defensive firepower.

Furthermore, if enemy ships are operating in EMCON, then its only means of detecting them is via IIR, and that has relatively less range, which is again a situation where a good targeting solution before launch is critical.

I found this very nice video from LM, illustrating many of the guidance features of LRASM (mid-course, passive RF, terminal IIR). In this video, the missiles sea-skimmed only in the terminal phase:

nlalyst said:

No, not really. If they are to have a reasonable chance to defeat a SAG with Type 052Ds, they have to arrive synchronized and in large numbers. To do that, you need to have a very good idea where the SAG is before launch. Otherwise, the missiles will be dispersed and arrive out-of-sync in small numbers, therefore unlikely to overwhelm the enemy's defensive firepower.

Click to expand...

What does that have to do with a Taiwan Straits scenario?

In the Taiwan Straits, you already know the exact location of a 50km box which contains a huge concentration of Chinese ships.

I would expect at least 10 destroyers with CEC and overlapping SAM coverage, with AWACs and fighter support.
Once we see quad-packed missiles on ships, I reckon there would be a minimum of 2000 defensive SAMs available.
Plus there will be at least 20 fighter jets overhead, picking off LRASMs as they come in.

So I just do not see enough LRASMs arriving to overwhelm the defenders.

Plus each LRASM costs $4M.
Whilst we don't know the cost of Chinese SAMs, we do know the cost for American defensive SAMs can be a lot less eg. SeaRAM, ESSM, SM-2

nlalyst said:

Furthermore, if enemy ships are operating in EMCON, then its only means of detecting them is via IIR, and that has relatively less range, which is again a situation where a good targeting solution before launch is critical.

I found this very nice video from LM, illustrating many of the guidance features of LRASM (mid-course, passive RF, terminal IIR). In this video, the missiles sea-skimmed only in the terminal phase:

Click to expand...

Again, how is this relevant to a situation where there is airborne AWACs and fighter cover over ships?
Or a situation where everyone knows where the defending ships are, so the ships might as keep their radars on all the time?
After all, the defending ships have a 99% probability of shooting down the incoming LRASMs after detection at the radar horizon.

And if LRASMs are flying high during the mid-phase, it just makes them easier to detect and kill.

This is a Taiwan Straits scenario, but a similar logic applies if China were to field LRASMs against a US Carrier Strike Group. The US forces would have AWACs and fighter cover, plus enough SAMs for any realistic number of Chinese LRASMs launched in a single wave.

So this is my reasoning on why LRASMs aren't that effective.

In regards to CMO testing, I felt stealth targets, no matter what size, get relatively easily detected when confronted with not a single radar but multiple radars. For example a J-20 seldom stays stealthy when flying right into the beehive that is a cross-strait air-war. Same applies to the notional F-22 that is sent to intervene in those scenarios. LRASM, on the other hand, is quite a pain. Its counter-detection range is just too low and a coordinated strike of even relatively few missiles is guaranteed to at least sink a single ship in a SAG. Nothing that can be said about non-stealthy subsonic sea-skimmers like the YJ-83.

As such, I'm sure the PLAN is actively pursuing stealth missiles. Ideally, China gets a LRASM version of the YJ-18.

Insignius said:

Its counter-detection range is just too low and a coordinated strike of even relatively few missiles is guaranteed to at least sink a single ship in a SAG.

Click to expand...

This part just sounds plain wrong to me.

A destroyer or frigate should be able to detect an LRASM at the radar horizon (30km)
Then 4 SAM engagement rounds should be 99% effective in shooting down the LRASMs

The problem is; you can detect it at 30km, but the targets are so small that you cannot get a good lock on them until much much closer. And at that point, your reaction time to intercept like a dozen of them coming for one single ship is too short.

Now, imagine this being a stealth YJ-18 with a Mach 3 terminal dash.

I guess one workaround would be quad-packed ImIR guided SAM. I do hope the FM-3000N or whatever variant the PLAN uses will have those.