Ракеты в DCS

[Hoarfrost]

А в зпс у мига тоже дальность поднимете?

[FoxAlfa]

Is the difference in ability to notch a supported and unsupported missile currently simulated?

[Chizh]

Alfa,

what is supported missile? 

[GGTharos]

A missile that receives information via missile datalink from the launch platform.    Some missiles will process this information even when terminal homing (AMRAAM for sure, probably the SD-10 and R-77 and many SAMs), increasing resistance to ECM, chaff, and helping to continue tracking a target through the notch or split-S (split-S countermeasures were already implemented in AIM-7E - it has no datalink but it has a little search mode to help with this).

[ZHeN]

target illumination for a semi-active missile is also often referred to as "supporting"

[GGTharos]

Yes, but the notch makes no sense if you're not illuminating.  There's no target, basically.

[FoxAlfa]

8 hours ago, Chizh said:

Alfa,

what is supported missile? 

Exactly what GGTharos said.  I feel that supported missiles should be less likely to notch since of the two radar angles, unsupported should be easier to notch due to small and weak radar (I know some ppl will disagree with me). Also, missiles fired in TWS should be less accurate then STT due to TWS inherent inaccuracies (especially in vertical where it can be off thousands of feet) 

Contributing factors to this way of thinking, we can see that per example Swedish air force train to support the Fox 3 till impact.

Also historically based on pilot accounts all the Aim-120 were supported till impact (also a great quote, missiles miss, that is why the called missiles) 

 

 

 

[TotenDead]

15 часов назад, GGTharos сказал:

 it has no datalink but it has a little search mode to help with this).

Search mode? With what could it search?

[Chizh]

16 hours ago, FoxAlfa said:

Is the difference in ability to notch a supported and unsupported missile currently simulated?

Yes, there is a difference. The supported missile overcomes the notch more easily.

After the missile has locked the target of its seeker, the support is terminated.

[GGTharos]

19 minutes ago, TotenDead said:

Search mode? With what could it search?

 

A target that will fit its doppler, range and angle gates within a certain amount of time.   In very simplified terms, it performs a mini-raster waiting for the target to fly out of the clutter line.

[nighthawk2174]

A few questions:
A) For proximity fuzes: Could it be possible to define essentially a "bubble" for every aircraft representing its approximate dimensions and then that value is subtracted out of the distance from the missile to the target?  That way you don't get missile missing because they didn't pass within 10ft of the pilots head?  
B) is it possible to make the target's computer a primary simulator of what is happening? Thus, if the missile is aimed at a target in the MP, that person's computer will process the simulation of what is happening as if it were in the SP updating the server with its calculations. I think the most important thing is that the target has an accurate idea of what is going on. If it turns out for the launch plane that the missile is a little laggy, in my eyes is an insignificant issue compared to the target having an accurate idea of what is happening.

C)

1 hour ago, Chizh said:

Yes, there is a difference. The supported missile overcomes the notch more easily.

After the missile has locked the target of its seeker, the support is terminated.

Is this just a percentage chance or will the targets position actually be continuously updated?  And lets say the missile is notched then re-acquires it doesn't stop receiving updates then does it?  As it should continue to receive them so long as the radar sees the target.

 

Would be nice also to incorporate lag into this, essentially if the radar passes over the target and sees it then the missile gets an update.  Not just continuously would make tws a bit less reliable at getting the missile through a notch and STT a lot better at this.  Although tbf for the amraam if its getting datalink updates couldn't it just throw open its vgate and re-acquire with the range gate?  Especially if in lookup or at a significant distance from terrain?

 

D) Will the amraam get MPRF and HPRF modes simulated?  As far as i'm aware, partially based on what i've seen in mace, they should have different sized notches, detection ranges, and fov's.

Edited March 10, 2021 by nighthawk2174

[BlackPixxel]

9 hours ago, FoxAlfa said:

Exactly what GGTharos said.  I feel that supported missiles should be less likely to notch since of the two radar angles, unsupported should be easier to notch due to small and weak radar (I know some ppl will disagree with me). Also, missiles fired in TWS should be less accurate then STT due to TWS inherent inaccuracies (especially in vertical where it can be off thousands of feet) 

 

I don't know if it would make much of a difference. If you notch the missile, you will very often notch the aircraft radar as well anyway (which has a wider notch gate). Still it would be interesting to see.

 

But for a proper implementation, DCS has to rewrite the radar memory mode mechanic from scratch. Right now memory/memery mode will receive the actual position of the aircraft for X seconds after losing the lock, which would result in the missile being 100% notch-proof for X seconds.

Instead the radar should actually extrapolate, and its track should deviate from the actual target position, especially if the target maneuvers.

 

Also, INS inaccuracy of the missiles has to be considered. The midcourse corrections work so well, because the missile activates its seeker quite far from the target, where the angular error is quite small. If it would now lose the target and fly by INS + midcourse correction for another while, then it might be that at the target location received from the datalink it will not find a target, because the position of the missile is off due to INS drift.

 

 

So it would indeed be nice to see this implemented, but ED has to be very carefull not to make it too simplified, as this would make it more powerfull than it should actually be.

Edited March 10, 2021 by BlackPixxel

[Chizh]

2 hours ago, BlackPixxel said:

But for a proper implementation, DCS has to rewrite the radar memory mode mechanic from scratch. Right now memory/memery mode will receive the actual position of the aircraft for X seconds after losing the lock, which would result in the missile being 100% notch-proof for X seconds.

Instead the radar should actually extrapolate, and its track should deviate from the actual target position, especially if the target maneuvers.

Our radar (in ED aircraft) actually extrapolates the target position. If the target is maneuvering at this moment, the position extrapolated by the radar will differ.

 

2 hours ago, BlackPixxel said:

Also, INS inaccuracy of the missiles has to be considered.

In the plans.

 

[BlackPixxel]

1 hour ago, Chizh said:

Our radar (in ED aircraft) actually extrapolates the target position. If the target is maneuvering at this moment, the position extrapolated by the radar will differ.

 

The radar might show the correctly extrapolated track, but the missile itself will not go towards the extrapolated position. The missile guided from a radar in memory/extrapolation mode of the radar will fly towards the actual target.

[GGTharos]

Just how much do you think these INUs drift?   Out of curiosity I found the part number for the 120's INU a couple of months ago - it's going to drift so little over the useful time of the missile that it just doesn't matter when you're activating a thousand times further than the size of the possible error.  Yep, drift is a thing but not quite the way people are thinking - in fact; given the accuracy of the instruments it's hard to tell how drift is a problem without knowing more, especially vs a singleton in a clear sky.

Edited March 10, 2021 by GGTharos

[FoxAlfa]

16 minutes ago, GGTharos said:

Just how much do you think these INUs drift?   Out of curiosity I found the part number for the 120's INU a couple of months ago - it's going to drift so little over the useful time of the missile that it just doesn't matter when you're activating a thousand times further than the size of the possible error.  Yep, drift is a thing but not quite the way people are thinking - in fact; given the accuracy of the instruments it's hard to tell how drift is a problem without knowing more, especially vs a singleton in a clear sky.

 

I think radar accuracy is more of issue, they are not laser beams. And seriously degrades with distance especially when trying to figure out altitude, TWS is most effected. 

[GGTharos]

IMHO, at the engagement ranges we're looking at, only a very old radar would have a radar cell that is particularly large.  Even with TWS, the sources of error from TWS itself, which are not modeled, are far larger than the INU drift.   While these INUs can have an order of 10deg/h of drift for some of the worst of them, the longest you can expect a missile to fly without any guidance is 60 seconds, so the drift is 1/60th of that value.  Pretty much any drift you compute will be tiny and you need other things to help the missile do things it shouldn't.

 

You're better off counting on breaking a TWS track  because of timing (ie. making a move at over 6g would likely make it unable to correlate) but then the attacking fighter can go to HDTWS and negate that.  Nowhere in here is the INU error large enough to cause enough problems in an obvious (to me) way, and that's assuming that the flight is completely uncorrected from launch to missile search.

 

I certainly don't understand how and why INU drift enters into the picture here, and I'd like to know.  Do you know?

Edited March 10, 2021 by GGTharos

[FoxAlfa]

23 minutes ago, GGTharos said:

IMHO, at the engagement ranges we're looking at, only a very old radar would have a radar cell that is particularly large.  Even with TWS, the sources of error from TWS itself, which are not modeled, are far larger than the INU drift.   While these INUs can have an order of 10deg/h of drift for some of the worst of them, the longest you can expect a missile to fly without any guidance is 60 seconds, so the drift is 1/60th of that value.  Pretty much any drift you compute will be tiny and you need other things to help the missile do things it shouldn't.

 

You're better off counting on breaking a TWS track  because of timing (ie. making a move at over 6g would likely make it unable to correlate) but then the attacking fighter can go to HDTWS and negate that.  Nowhere in here is the INU error large enough to cause enough problems in an obvious (to me) way, and that's assuming that the flight is completely uncorrected from launch to missile search.

 

I certainly don't understand how and why INU drift enters into the picture here, and I'd like to know.  Do you know?

 

INS rounds get CEP to ~50m for 60 sec flight and that is new tech and biggest INS error producing part is path change that is more present in A to A missies than arty round. We are not talking about two static points with exact positions to start with. There is a good reason why you do INS correction after take-off SID is done. Is the accuracy still good enough, yes, but error is not neglectable. 

https://www.army.mil/article/111566/new_guided_munition_sensors_are_greater_than_sum_of_their_parts

Edited March 10, 2021 by FoxAlfa

[Кош]

Не знаю спрашивали ли. Симулируется ли ограничение по скорости линии визирования в градусах в секунду для ракет ВВ, и для всех ли? 

[GGTharos]

This is about miniaturization, not INU accuracy in a missile.   I don't know what sort of INU missiles before AMRAAM used, but for the 120 itself:

 

https://apps.dtic.mil/dtic/tr/fulltext/u2/a581016.pdf

 

Quote

A well-known example of this type of accelerometer is Northrop Grumman’s SiAc™, of which over 20,000 have been produced. Two versions have been developed (tactical grade and inertial grade) and have wide usage, such as AMRAAM, GMLRS, and Commanche helicopter. Other examples are Honeywell, Colibrys (Switzerland), Applied MEMS Inc., Silicon Designs, Sherborne Sensors (UK), Bosch (Germany), and numerous others.

 

10 minutes ago, Кош said:

Не знаю спрашивали ли. Симулируется ли ограничение по скорости линии визирования в градусах в секунду для ракет ВВ, и для всех ли? 

 

I believe ( but may be wrong) that it is a mix, with older/newer code present depending on the missile.  Unless the seeker speed is very slow, it will only affect very old missiles while they are tracking.  If you are concerned about search speed and search patterns when the missile is not locked, it definitely has an effect there.

Edited March 10, 2021 by GGTharos

[Chizh]

40 minutes ago, Кош said:

Не знаю спрашивали ли. Симулируется ли ограничение по скорости линии визирования в градусах в секунду для ракет ВВ, и для всех ли? 

Да, максимальная угловая скорость прописана для всех ракет ВВ.

[dundun92]

13 hours ago, Chizh said:

Yes, there is a difference. The supported missile overcomes the notch more easily.

After the missile has locked the target of its seeker, the support is terminated.

Im a bit confused. Does this mean that a missile that is supported only has higher resistance to notch when it initially goes active? Or is it more notch resistant for the entire TOF?

Edited March 10, 2021 by dundun92

[Chizh]

57 minutes ago, dundun92 said:

Im a bit confused. Does this mean that a missile that is supported only has higher resistance to notch when it initially goes active? Or is it more notch resistant for the entire TOF?

 

It is difficult to say unequivocally here. The radar of the firing aircraft may not be able to track the target in the notch and then there will be no support. On the other hand, a missile with an activated seeker operates at a medium PRF and more resistant to notches at a short range (it has a lower threshold value for the minimum radial velocity of the target).

[dundun92]

16 minutes ago, Chizh said:

It is difficult to say unequivocally here. The radar of the firing aircraft may not be able to track the target in the notch and then there will be no support. On the other hand, a missile with an activated seeker operates at a medium PRF and more resistant to notches at a short range (it has a lower threshold value for the minimum radial velocity of the target).

So if im understanding right, once the missile goes active there's no sort of support in terms of helping it to reacquire, instead it has a lower notch gate value? And if you drop the lock before it goes active, it does not use this lowered notch gate value?

Edited March 10, 2021 by dundun92

[GGTharos]

1 hour ago, Chizh said:

It is difficult to say unequivocally here. The radar of the firing aircraft may not be able to track the target in the notch and then there will be no support. On the other hand, a missile with an activated seeker operates at a medium PRF and more resistant to notches at a short range (it has a lower threshold value for the minimum radial velocity of the target).

 

I understand that in DCS once the seeker acquires, it no longer listens to the m-link.

 

We know from documentation that IRL this works in various ways for a number of missiles:

 

- R-27 may or may not listen to m-link at all times, but what we do know is that the radar terminates m-link messages at some range and they are simply not available - they are replaced with a guidance/homing signal instead

- AIM-7 has no m-link, so it must lock onto the target shortly after it is launched.   Therefore the launch range is RCS dependent.

- AIM-54 has an m-link that it listens to in mid-course flight and any time it is searching for a target - in other words, if it's not searching or guiding in terminal, it's listening.  This seems to include if lock is lost but can't be too sure.   The point is, the radar never terminates support.

- AIM-120 listens to the m-link as long as it is available to help with ECCM and accurate target selection if multiple targets are present.   Yes, MPRF is a big deal but it is a very short-range affair, the missile uses HPRF for search and acquisition before it transitions to MPRF.    I expect missiles like R-77, R-37, SD-10 will act in a similar way.

 

From the above you can probably imagine where there would be benefits from m-link capability vs a notch, chaff, or ECM.

 

 

54 minutes ago, dundun92 said:

So if im understanding right, once the missile goes active there's no sort of support in terms of helping it to reacquire, instead it has a lower notch gate value? And if you drop the lock before it goes active, it does not use this lowered notch gate value?

 

Unless something has changed in the missile code, the notch gate value is strictly range-dependent.