Rework of basic SAMs features is needed (not talking about IADS or EW)

[Mad_Shell]

SAMs are currently plagued with a lot of issues affecting their performances, especially linked to flawed guidance systems.

 

Missiles guidance systems:

Several trajectories are possible to intercept a flying target, and mathematical methods have been developped to find the most efficient ones. IRL, SAMs use methods such as:

- (advanced) proportionnal approach

- half-straightening approach

- three points method

- modified versions of some of the above methods also exist for low altitude targets to avoid the SAM to run into the ground.

 

The discussion of those methods is way beyond the scope of this post, but basically missiles will use the most suitable method during their flight to be the most efficient (intercept the target with the most energy possible). Sometime a missile will switch method mid fligth, or even use at the same time a method in the horizontal plane, and another method in the vertical plane! And it allows to avoid having this happening IRL...  I don't know exactly what guidance is used in DCS, but it looks like SAMs always try to lead targets, even when they are high G maneuvering at long distance. SAMs bleed all their energy way faster than they would do IRL, because IRL a SAM would not try to lead the target that much for most of the flight. 

I know implementing exactly the specific methods used by specific SAMs would be a daunting task, and that's not what I ask. Simply some more efficient guidance against high G maneuvering targets would already go a long way in making SAMs not behave in a ridiculous way. 

 

It is very possible that some missiles speeds are incorrect too. After some testing the 5V55R missile of the S-300 P SAM system reaches a maximum TAS of around 2500 kts (~ mach 4) in DCS, while several sources indicates a maximum TAS of more than 4000 kts(~ mach 6) IRL. As a result the maximum engagement range also seems slightly lower in DCS compared to IRL (~40 nm vs >50 nm).

Edited December 12, 2020 by Mad_Shell
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[Northstar98]

4 hours ago, Mad_Shell said:

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Agreed, though it depends on the precise nature of the system too. This plays into other things like tactics and missile flight modelling, which in some cases seems a little funny and SFM-y.

 

There's also things like employing certain tactics like firing effectively blind and delaying the use of an FCR (be it an illuminator or otherwise) a real tactic used in Serbia.

 

At the moment though, all air defences are simplified, be it the guidance systems or the missile flight dynamics or both. That and how the AI behaves.

 

4 hours ago, Mad_Shell said:

It is very possible that some missiles speeds are incorrect too. After some testing the 5V55R missile of the S-300 P SAM system reaches a maximum TAS of around 2500 kts (~ mach 4) in DCS, while several sources indicates a maximum TAS of more than 4000 kts(~ mach 6) IRL. As a result the maximum engagement range also seems slightly lower in DCS compared to IRL (~40 nm vs >50 nm).

 

This might be due to missile flight dynamics, but it's important to note the parameters under the max speed figure is obtained. 

[Harker]

SAMs are in need of a rework, both in terms of guidance algorithms and missile top speed/burn time and drag values. Also, the Patriot and SA-10 should be able to fire in track via missile (TVM) mode, giving no launch warning whatsoever to the targeted airplane, making them much more dangerous and true area denial systems (how long are you going to fly in an area, not knowing if a missile is headed your way at Mach 4 or not?). I am unsure if the variants we have in DCS have that capability, however, so maybe someone else can chime in.

Edited December 12, 2020 by Harker

[Northstar98]

25 minutes ago, Harker said:

SAMs are in need of a rework, both in terms of guidance algorithms and missile top speed/burn time and drag values. Also, the Patriot and SA-10 should be able to fire in track via missile (TVM) mode, giving no launch warning whatsoever to the targeted airplane, making them much more dangerous and true area denial systems (how long are you going to fly in an area, not knowing if a missile is headed your way at Mach 4 or not?). I am unsure if the variants we have in DCS have that capability, however, so maybe someone else can chime in.

 

 

Doesn't TVM require illumination? As I understand it, It's essentially SARH but commands are data-linked to the missile instead of the missile working it out by itself.

 

It might be the case that the 5V55R is TVM/Command Guided similar to how TWS fired fox-3's work (obviously using an off-board illuminator and guidance in the case of TVM), so the missile is command guided (similar to earlier 5V55) and then TVM is used for terminal homing. Don't quote me on that one, it's speculation. 

 

I know that at least the SM-2 has SARH/DL using SARH in the terminal phase with illumination provided by the SPG-62 RADARs (at the moment the missiles seem to be pure SARH, with the SPG-62 completely non-functional, though it is at least animated on the Arleigh-Burke. However, on the Oliver Hazard Perry class frigate, the illuminator RADAR (STIR) for the Mark 92 GMFCS is completely absent, and only the Combined Antenna System is present, which AFAIK only provides acquisition and tracking, but not illumination).

Edited December 12, 2020 by Northstar98

[Harker]

From what I understand, TVM requires illumination, but the signal doesn't change to a SARH signal, since the missile doesn't home on the reflected energy. You'll get a lock signal, but not a launch signal. And if guidance can be achieved with a TWS-type wave, you won't even get a lock signal. If the guidance changes to SARH or ARH during the terminal phase, you'll get a launch warning of course, but at this point, it'll probably be too late.

Admittedly, I'm not very knowledgeable in SAM-specific FCRs, guidance etc, I'm just listing a few things I've picked up over the years in conversations with IRL pilots. I've been told that if you see a 10 or a P on your RWR, you should expect that a missile is could be either ready to launch at you or it's launched already. It's safer to just leave than take that chance.

Edited December 12, 2020 by Harker

[Northstar98]

14 minutes ago, Harker said:

From what I understand, TVM requires illumination, but the signal doesn't change to a SARH signal, since the missile doesn't home on the reflected energy. You'll get a lock signal, but not a launch signal. And if guidance can be achieved with a TWS-type wave, you won't even get a lock signal. If the guidance changes to SARH or ARH during the terminal phase, you'll get a launch warning of course, but at this point, it'll probably be too late.

 

I see, kinda like how the Phoenix is supposed to work when fired in TWS before going active; using reflections from the RADAR sweeping over the target (but not STT-ing or using another illumination mode like PDI or CWI), though in the case of the Phoenix in combination with DL (which I would assume is the case with the 5V55R, the older 5V55s were purely command guided AFAIK, with the Flap Lid providing both tracking and uplink)

 

Quote

Admittedly, I'm not very knowledgeable in SAM-specific FCRs, guidance etc, I'm just listing a few things I've picked up over the years in conversations with IRL pilots. I've been told that if you see a 10 or a P on your RWR, you should expect that a missile is could be either ready to launch at you or it's launched already. It's safer to just leave than take that chance.

 

Neither, I'm just going on what I can research. I guess it's especially difficult with systems like the SA-10 which has a phased-array antenna for its FCR, and I'm assuming scan rates are much more rapid and work in a way that's closer to the F-16C's situational-awareness mode (just more rapid). Though, like much of the rest of the AI, it's probably simplified. I know for a fact that certain RADAR modes aren't implemented in DCS, and that will probably remain the case until a major overhaul is done.

Edited December 12, 2020 by Northstar98

[Mad_Shell]

5 hours ago, Northstar98 said:

This might be due to missile flight dynamics, but it's important to note the parameters under the max speed figure is obtained. 

I agree, that's why I said "very possible". But the results seem pretty consistent, the S-300 fired at several targets at different ranges and altitudes, and in the best cases there was still a ~1500 kts gap compared to IRL according to the sources I found. And no way exterior parameters such as temperature, wind, humidity etc can affect speed that much. 

[Northstar98]

12 minutes ago, Mad_Shell said:

I agree, that's why I said "very possible". But the results seem pretty consistent, the S-300 fired at several targets at different ranges and altitudes, and in the best cases there was still a ~1500 kts gap compared to IRL according to the sources I found. And no way exterior parameters such as temperature, wind, humidity etc can affect speed that much. 

 

In that case it's probably SFM-isms of missile flight dynamics (let alone guidance), similar to how the AMRAAM was before it got updated.