Thin FOG prevents IR AGM missiles?

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All Forums >> [New Releases from Matrix Games] >> Command: Modern Operations series >> Thin FOG prevents IR AGM missiles?

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Thin FOG prevents IR AGM missiles? - 7/26/2017 11:28:13 AM

morphin

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Hi

Can i use the AGM-154C and AGM-158A with thin FOG (0-2k)?. Those weapons have an IR termination guide and i'm not sure if this works on thin fog level....

Thank's
Andy

Post #: 1

RE: Thin FOG prevents IR AGM missiles? - 7/26/2017 11:45:01 AM

Dysta

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Yes. Tested it and the fog can limiting (not entirely blocking) IR seekers in various circumstances. Like at high altitude it can see everything just fine as long as both seeker and target are above fog level.

Please note that even the densiest fog setting, the IR can still somehow seek the stationary target in fog, but when the target is mobilizing the IR searching will becomes more difficult, and is possible to miss/dodge.

_____________________________

(in reply to morphin)

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RE: Thin FOG prevents IR AGM missiles? - 7/26/2017 12:43:16 PM

morphin

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From: Switzerland
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Thank's Dysta

Target is at the ground for those missiles :-)

Andy

(in reply to Dysta)

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RE: Thin FOG prevents IR AGM missiles? - 7/26/2017 5:07:42 PM

DWReese

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I've been told that smoke plays havoc on laser-guided bombs (like GBUs). I'm not sure if that is true, or not.

I have been trying to get the devs to introduce smoke as a feature into the game. It is reportedly on "the list" of things to do.

I was wondering, could the existence of fog (as a substitute) have the same effect as smoke? Would it work?

Thanks in advance.

Doug

(in reply to Dysta)

Post #: 4

RE: Thin FOG prevents IR AGM missiles? - 7/28/2017 9:03:13 AM

zaytsev

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For laser.
Just imagine billions of microscopic water particles which act like semi-mirrors on a path from laser to target.
It doesn't stop the beam , but it surely does induce 'noise' by re(de)flecting it in random., reduces range for sure.

Same thing is anti laser defense on tanks, smoke/vapor screen, when few times larger then tank itself and thick enough it reflects and
disperse the beam in random making ranging/targeting inacurate.

IR
Clouds and water vapor (like fog), denser, the better blocker, have so-so similar adverse effects on propagation of thermal waves.
Also, it is 'cooling' (absorbing) the same thermal wave, because the 'medium' is colder then 'information', by laws of thermodynamics,
so reduces the propagation, therefore reduces range of dispersion.

Don't mistake thinking that if it is colder surrounding so because of 'contrast' that you can 'see' heat further.
Yes, but, that's IRST principal that works in high atmosphere where is really cold and too high for clouds/vapor/fog, so, 'clear sky'.

Here we are talking about 'dirty' atmosphere full of particles, so, if you like, noisy medium.

So both examples are pure physics, wave propagation. Air/fog being the medium and IR(heat)/Laser being the information.

Simple :)

Cheers

< Message edited by zaytsev -- 7/28/2017 9:10:14 AM >

(in reply to DWReese)

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RE: Thin FOG prevents IR AGM missiles? - 7/28/2017 9:54:06 AM

Gunner98

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quote:

I've been told that smoke plays havoc on laser-guided bombs

I think that generally speaking - this is true. But as Zaytsev says with water vapor, there are a lot of variables - not all smoke is the same.

Smoke HC (Hexachloroethane) will block visual and Laser but generally not thermal or IR. Affected by strong winds
Smoke WP (White Phosphorus) will block thermal but is less effective in hot temperatures as it tends to 'pillar' leaving gaps in the screen. Also has some Geneva Convention issues.
Smoke RP (Red Phosphorus) quite good against thermal and IR - believe it or not - quite good at night!

There are other types as well but the thing to remember is that artificial smoke is generally put in place to blind or screen from the ground not the air - so an airborne Laser, if it has the time to search will generally find a way through the smoke unless it is completely engulfing the target.

Natural smoke is another matter. A lot of variance from light wood smoke to heavy oil smoke, from single pillars to blanketing an area of 100,000 Sq miles - and is much less transient than artificial smoke, so difficult to model.

B

(in reply to DWReese)

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RE: Thin FOG prevents IR AGM missiles? - 7/28/2017 10:45:34 AM

DWReese

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What about using GPS to guide weapons? I assume that many of these GBU bombs can be either laser-guided or use GPS. Smoke obviously won't have any effect on GPS-guided weapons, but I guess that there are also such things as GPS-jammers. So, when does a weapon like a GBU-31 use a laser for guidance, and when does it use GPS? Are these in the game? I've never really paid any attention. I've just aimed the weapon and fired. Can you, or someone else, explain how this works in game terms?

Thanks

Doug

(in reply to Gunner98)

Post #: 7

RE: Thin FOG prevents IR AGM missiles? - 7/28/2017 11:00:52 AM

Gunner98

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Doug

Having two guidance systems on something as small as a bomb is a relatively recent capability. The LJDAM, I think its the GBU-54 not sure if there are other sizes, but this is the 500lb version. So if the target is moving you use the laser and if it is stationary you use the GPS guidance. Your correct that GPS guidance is not affected by smoke or weather (theoretically) but can only hit stationary targets because the coordinates are entered just before bomb release and if the target moves - the bomb will miss but very precisely!

GPS jamming is a subject that is hotly debated as to its effectiveness on a bomb or artillery bullet. These have inertia and ballistics going in their favour, and GPS jammers have a limited range (to the best of my understanding). If your able to jam out at source - i.e. the satellite cluster, that is another story and you won't be worrying about accuracy of a 500lb bomb! So the GPS jammers I know about will protect a precise target by causing the GPS guided munition to lose track in the terminal phase of its delivery - so it will likely miss but just by a little bit. Better have your helmet on and be well under ground anyway.

The Americans call this weponeering, which I don't think is a real word, but selecting the right weapon for the right target is a job in itself.

B

(in reply to DWReese)

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RE: Thin FOG prevents IR AGM missiles? - 7/28/2017 3:12:47 PM

Cik

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as far as i know GPS jamming won't really affect a JDAM- like most aircraft it's GPS/INS guidance which means it won't become useless the second it's jammed. it's fix will eventually lose accuracy without being updated by an external source (host plane or GPS update)

as far as i know JDAMs are designed to be "stealthy" in that they don't emit and don't receive. it's why, for instance, they don't use some sort of radio-guidance where they accept steering commands from outside sources.

once it's off the plane, it's standalone AFAIK.

(in reply to Gunner98)

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RE: Thin FOG prevents IR AGM missiles? - 7/28/2017 5:07:27 PM

Gunner98

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You're right that JDAMs don't emit anything.

As to the error - it will be small, but once they lose connection with the GPS feed/INS feed from AC, they will 'go ballistic'. This is much less dramatic then the proverbial term implies. It simply means that they no longer receive updates to correct for wind, rotation of the earth etc. With a bomb that is coming nearly straight down it will have very little effect but, it might cause it to miss its aim point by a small distance, that could still very well be a hit on the target but not the spot it was aimed.

I am not sure about bombs, but with GPS guided artillery rounds a BIP (Ballistic Impact Point) needs to be calculated and collateral damage (or safety in training) need to be considered for that as well as the target. We are not talking large miss distances.

B

(in reply to Cik)

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RE: Thin FOG prevents IR AGM missiles? - 7/29/2017 3:25:06 AM

DWReese

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I've read several studies involving attacks on underground targets which are requiring an air-launched ordinance to be directed to an aim-point which it will hit. Since it lacks the power to completely bore through to the target, a second round must be fired and it will need to hit the same aim-point to continue trying to reach the underground target. I don't know what this practice is actually called, or if it actually exists.

My question is, if the air-launched ordinance was a GBU-28 (BLU-109, could it be jammed/diverted/spoofed enough so that it would not hit the exact area as prescribed above, or are we talking about a large enough hole initially that anything close would still be "in the same hole" as the first shot? If you don't understand what I am saying, that's okay. I'm not sure that I understand me, either. <g>

Doug

(in reply to Gunner98)

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RE: Thin FOG prevents IR AGM missiles? - 7/29/2017 8:53:34 AM

Gunner98

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I've read about the same thing, almost like drilling through something in a series of craters. I'm really not sure what its called. Also not sure on your question, just don't know.

B

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Post #: 12