Does fog/Cloud block igla abilities?

[dooom]

anyone know if an igla manpad can see you if you are above a cloud/fog layer in game?

[BaD CrC]

Well, at least in the real world, Igla is infrared. So fog is not really an issue. The Igla manpad can optionaly be equipped with a thermal imager I believe so the operator can actually see what he is locking on (lock is automatic on Igla. You press the button on manpad and wait for the continuous beep, then it launches without further action from operator).

For the clouds, well, my real world experience is that you may lock on clouds sometimes when the a/c is flying behind them, and so loose the lock.

 

For in game, absolutely no idea, but I'd be surprised.

[Speed_2]

Well, at least in the real world, Igla is infrared. So fog is not really an issue. The Igla manpad can optionaly be equipped with a thermal imager I believe so the operator can actually see what he is locking on (lock is automatic on Igla. You press the button on manpad and wait for the continuous beep, then it launches without further action from operator).

For the clouds, well, my real world experience is that you may lock on clouds sometimes when the a/c is flying behind them, and so loose the lock.

 

For in game, absolutely no idea, but I'd be surprised.

 

Fog is very much an issue for IR sensors. While IR can penetrate fog better than visible, fog can very strongly attenuate IR energy. Exactly how much attenuation depends on the size of the fog droplets and the exact IR wavelength. If the droplets are on the order of the size of the wavelength or larger, you're in trouble. Considering that long wave IR is around 8-12 microns, and you can often FEEL fog droplets against your skin, IR is usually attenuated pretty heavily by fog. There are other considerations also besides just particle size vs wavelength, these are more complicated and often specific to the substance doing the attenuation.

 

To make matters worse, the Igla would probably operate in the 3-5 micron range, meaning even worse attenuation by fog.

 

In short, the Igla should not work in very foggy conditions.

Edited November 20, 2009 by Speed_2

[Vekkinho]

anyone know if an igla manpad can see you if you are above a cloud/fog layer in game?

 

It can, clouds and fog present no issue in game for AI MANPAD unit and other AI IR SAMs.

 

IRL however IR MANPAD ability to track is compromsed with fog and clouds.

[Speed_2]

I did a quick google search, and here's a link to an webpage that shows an attenuation (in dB) vs. wavelength plot for IR energy under three different fog scenarios- look on the second page of the .pdf: http://www.systemsupportsolutions.com/whitepapers/KorevaarJan02.pdf

 

As you can see, the IR energy is heavily attenuated. Note that while the "maritime fog" scenario looks like not very strong attenuation, that is ONLY relative to the continental fog and cumulous cloud scenarios. According to these plots, in mid-wave IR, the attenuation for maritime fog is maybe 30dB/km on average across that spectral window. That means that the signal power will be reduced by a factor of 1000 after passing through a kilometer of maritime fog. Obviously, you aren't going to be seeing very far in midwave IR under such conditions. The long wave IR is even worse.

 

These plots also show an interesting peak in attenuation starting around 3 microns and going to perhaps 12 microns (off the edge of this plot). I believe this is due to the attenuation of IR energy specific to water vapor- but I don't know for sure. While the overall trend in attenuation is that the smaller the particle and the longer the wavelength, the less the attenuation, this is an overall TREND, and as I already mentioned, specific substances can absorb heavily in specific bands.

 

That said, I could swear that I remember running some simulations where IR was less heavily attenuated- but still heavily attenuated- than visible under foggy conditions. These scenarios seem to show the reverse. It may be due to different assumptions about the fog in these specific simulations.

Edited November 20, 2009 by Speed_2

[BaD CrC]

Guys, we are talking about locking on a very hot surface like a turbine exhaust with gases temp several hundred of degrees C. Today's military thermal imager can deal with temperature differences down to 0.1°. You can attenuate whatever you want with whatever fog, I garantee one will get a lock on you.

[Speed_2]

Guys, we are talking about locking on a very hot surface like a turbine exhaust with gases temp several hundred of degrees C. Today's military thermal imager can deal with temperature differences down to 0.1°. You can attenuate whatever you want with whatever fog, I garantee one will get a lock on you.

 

 

Actually, a noise equivalent temperature difference (NETD) of only 0.1 degrees K is quite aweful, I tested systems that are down around 20mK or even better.

 

Even if you had an INCREDIBLY hot delta T of 500 degrees K, which you WON'T with a helo (this is more like looking up a fighter's tailpipe), that energy is attenuated by 30 dB per km under that maritime fog scenario I found (keep in mind, that was, by far, the LEAST attenuation). 30 dB is a factor of 1000 PER KILOMETER. That means a target 2km away will have its IR signature reduced by a factor of a MILLION- 1000 times after the first kilometer, and then that 1/1000 of the original signal gets attenuated by another factor of 1000 over the second kilometer. So now that very hot 500 degree delta T is now 500K/1000000 = 0.5mK. Since the best NETDs I've ever heard of are only around 10mK, that signal is now 20 times below the noise level. Nothing can detect that.

 

Thirdly, your missile will have large pixels- in fact, missiles like the Stinger only have a SINGLE IR detector that is rapidly scanned to form a psuedo-image. No matter how hot your source, if it is angularly smaller than the IFOV (field of view of a single pixel) then that delta T will get averaged out over the entire IFOV of that pixel. Since hot sources tend to be small, either due to range or due to the fact that heat transfer only allows a very small spot to get really hot, then you're typically spreading that very bright spot out over an area, reducing its effective signal.

 

 

Finally, how the hell is anyone supposed to aim a shoulder launched IR SAM at a target that they cannot see visually due to fog?!

 

So I don't care how much of a guarentee you are giving. The fact is fog can, and does quite often, get bad enough to defeat the best IR imagers ever designed. Now, sure, you can use IR under sorta foggy conditions. We're talking about pretty thick fog here.

Edited November 20, 2009 by Speed_2

[Frederf]

I'm pretty confident that is someone hands you a SA-9 or a FIM-whatever stinger and your task was to shoot down a Ka-50 in poor weather that you'd have a heck of a time of it.

 

I mean you have to know where it is without seeing it. Point the Ingla at the target without seeing it until you get a tone. I assume the angular limits of the tracker are pretty small, 1-3° or so. Then there's the issue of having a strong enough IR source to even lock on to if you somehow miraculously got it pointed in the right direction.

 

Maybe with some IADS where you have a vehicle-based or fixed IR SAM launcher getting fed radar data from another system for pointing. You'd then have to have the IR missile fire nearly blindly and hopefully get a lock en route as the IR signal was less attenuated. But a MANPAD? No way.

[26-J39]

I think to truly know how an igla will perform in foggy conditions you need to have more specific technical information on the type of igla used firstly and specific details on is targeting/tracking system. Also, i don't think a manpad operator needs to see the target.. If an operator heard a helo fly over he could point, wait for tone and fire. This could be wrong tho cauz i never used one..:D

 

*edit- just did a quick google- first link: http://www.sciencedaily.com/releases/2006/05/060503100242.htm

Edited November 21, 2009 by 26-J39

[26-J39]

Maybe Igla's now using these: http://www.flir.com/uploadedFiles/ENG_01_FOG.pdf :D

[BaD CrC]

Speed-2, you can do all the calculations you want, this doesn't match field experience. I worked for 7 years as technical assistance for air defense systems and I have seen my share of live firings. So maybe it wasn't exactly the 'maritime fog' you are describing and maybe it wasn't Igla, but the leftover of this drone target I witnessed that blew up 3km away should make you re-think of your theory, because the visibility was really crap at this time.

Secondly, I have visited the manufacturer of this missile and manpads, south of Moscow, many years ago, and the IGLA manpad comes with an thermal camera in option that can be mounted close to where the IFF antenna is. So it is perfectly possible to use a manpad in bad weather conditions.

Frederf, I played with an IGLA manpad trainer (the missile got only the electronics and IR sensor working), locking the aircraft taking off from the nearby sukkoi factory, and I can tell you that this toy is a real piece of cake to use. It takes really no time to understand and use it.

As for a Ka-50 thermal signature, well I never had the chance to see one for real, even less to try to lock it with my systems, but we had a go with a UK AH-64 Apache a few years ago (lock only, not firing of course :P), and this big thing is pretty bright on IR once it turns its back (exhaust and tail rotor). OK, at this time, the weather was good.

I would agree that the most difficult part is to find the target in the middle of the sky as it is quite hard to spot something so small and that you can't even hear (until it's too late generaly).

 

Anyway, off topic discussion as I think the question was for the game play in BS, not real world.

[Speed_2]

Maybe Igla's now using these: http://www.flir.com/uploadedFiles/ENG_01_FOG.pdf :D

 

Excellent article! Good find.

[Speed_2]

Speed-2, you can do all the calculations you want, this doesn't match field experience. I worked for 7 years as technical assistance for air defense systems and I have seen my share of live firings. So maybe it wasn't exactly the 'maritime fog' you are describing and maybe it wasn't Igla, but the leftover of this drone target I witnessed that blew up 3km away should make you re-think of your theory, because the visibility was really crap at this time.

Secondly, I have visited the manufacturer of this missile and manpads, south of Moscow, many years ago, and the IGLA manpad comes with an thermal camera in option that can be mounted close to where the IFF antenna is. So it is perfectly possible to use a manpad in bad weather conditions.

Frederf, I played with an IGLA manpad trainer (the missile got only the electronics and IR sensor working), locking the aircraft taking off from the nearby sukkoi factory, and I can tell you that this toy is a real piece of cake to use. It takes really no time to understand and use it.

As for a Ka-50 thermal signature, well I never had the chance to see one for real, even less to try to lock it with my systems, but we had a go with a UK AH-64 Apache a few years ago (lock only, not firing of course :P), and this big thing is pretty bright on IR once it turns its back (exhaust and tail rotor). OK, at this time, the weather was good.

I would agree that the most difficult part is to find the target in the middle of the sky as it is quite hard to spot something so small and that you can't even hear (until it's too late generaly).

 

Anyway, off topic discussion as I think the question was for the game play in BS, not real world.

 

Sure, IR works in light and moderate fog, never said it didn't. The simple fact of the matter is, it will NOT work in heavy fog. You can't dismiss my OWN experience on this subject either, which was to test and simulate IR sensors under different weather conditions for the US Army. That IR is heavily attenuated to the point of opacity in heavy fog is a simple fact, and many, many sources can back this up- for example, the article just linked by 26-J39. Furthermore, all your live fire experience that you claim to have is of no use in answering this question if you never live fired under heavy fog, which is the scenario I am talking about.

 

No matter the level though, fog attenuates IR. It doesn't penetrate fog like radar does. Fog will reduce detection and tracking ranges for IR systems, and heavy fog will make the system useless.

 

I'm not sure there is really an arguement here, maybe just a misunderstanding. What you describe as having experienced in no way contradicts what I am saying. You say you witnessed an IR missile being used under foggy conditions- there is not a problem with that PROVIDED that the fog is not so heavy that it does not reduce the target signal so much that the target cannot be tracked by the missile! Secondly, you never fired under heavy fog conditions where IR is rendered useless.

 

The reason I have been considering heavy fog this whole thread is because heavy fog was seemingly implied by the original poster.

[Frederf]

Just for curiosity's sake (and not really in line with the heavy fog thing):

 

Is it possible for an IR SAM to attack an aircraft flying above a solid cloud layer at for example from 4,000 to 6,000?

[Speed_2]

Just for curiosity's sake (and not really in line with the heavy fog thing):

 

Is it possible for an IR SAM to attack an aircraft flying above a solid cloud layer at for example from 4,000 to 6,000?

 

No, clouds are completely opaque- clouds are very thick fog :)

[BaD CrC]

Speed-2: I think indeed that there is no argument as you made your calculations using simulations based on mathematical models, and I have field experience of this kind of thing, but with no scientific measurements of the conditions at this time. Although strongly cartesian, I am always a bit sceptic with those simulations as models are just what they are. Approximation of reality. If we had to listen to the 'simulation guy' of the company I was working for 4 years ago, the odds to hit the target with our new system were so low, that it was not even worth going to the firing range. Finaly, we got 4 sucessful hits out of 4 firings.

 

Fredert, problem with clouds are when they are broken/scatered as the brutal gradient triggered by the target suddenly flying behind a cloud is often enough to deeply upset the algorithms.

[Frederf]

I was talking about complete 8/8ths overcast. I was wondering not if you could get a lock through clouds but more on the idea of a fire-without-lock and then acquire the target for the first time once the missile was above the clouds. Sounds pretty tricky.

 

Anyway, Post #3 went off topic and we have never been back since. First of all I would assume the SA-9s in the game in Georgian rebel hands are not the newest all-the-options just-came-out-Tuesday super rare optional equipment models but rather more mundane export versions from older inventory.

 

Can the SA-9s shoot you in game? Probably all the time. I don't think clouds make one lick of difference to the AI. Maybe prevailing visibility but not the physical cloud objects. It rarely comes up because being on top of the clouds usually puts you well above MANPAD range anyway.

[26-J39]

Can the SA-9s shoot you in game? Probably all the time. I don't think clouds make one lick of difference to the AI.

 

I think you answered your own question there.. as previously posted the AI are not inhibited by fog/cloud in DCS..

[Speed_2]

Speed-2: I think indeed that there is no argument as you made your calculations using simulations based on mathematical models, and I have field experience of this kind of thing, but with no scientific measurements of the conditions at this time. Although strongly cartesian, I am always a bit sceptic with those simulations as models are just what they are. Approximation of reality. If we had to listen to the 'simulation guy' of the company I was working for 4 years ago, the odds to hit the target with our new system were so low, that it was not even worth going to the firing range. Finaly, we got 4 sucessful hits out of 4 firings.

 

Fredert, problem with clouds are when they are broken/scatered as the brutal gradient triggered by the target suddenly flying behind a cloud is often enough to deeply upset the algorithms.

 

That's a pretty ridiculous position you have. That the models could be so far off reality is impossible considering that MODTRAN has been in development for something like 20 years or more. There have been COUNTLESS scientific papers on it, and real life data take to validate its predictions, many refinements to make it even more accurate. In short, MODTRAN IS very, very close to reality. The US military and scientific establishment didn't spend millions of dollars and 20+ years developing a model that could be wrong on such an INCREDIBLY basic question of whether fog will reduce the effectiveness of IR. Despite your experience you have, YOUR experience DOES NOT include the effect of fog on IR systems. Just because it was a little foggy outside and your system was able to hit a target doesn't mean the system performance, such as detection range or tracking range, was not degraded. It was only NOT degraded to the point of uselessness. It WOULD HAVE BEEN if you had been socked in under very foggy conditions.

 

Don't forget, I also tested IR systems too, but with the specific goal of trying to determine the LIMITS of their performance- something it sounds like you didn't do. Sounds like you were just testing if they would still WORK. If your target is sufficiently hot, and the fog isn't too bad, they will still see the target just fine. But if the fog gets thick enough, you're looking at attenuations on the factor of many tens of dB over just a km, and you won't see didley squat.

 

Finally, IR systems stop tracking things when the fly behind thick clouds because they CANNOT SEE through clouds. If you don't know that, then you do not have the experience you claim to have. I've seen plenty of IR videos of aircraft flying around/through clouds. After all, one of the projects I was involved with was a large aperture IR system being used as a target aquistion and tracking adjunct system on radar guided SAM system. Clouds are opaque. Now, a thin cloud layer can be seen through, but the vast majority of clouds aircraft might flight behind- like cumulous- are thick.

 

Now sometimes, it can appear as though the IR system is still tracking the target, even when it is behind a cloud and invisible on the TV image being returned from the sensor. That is because the tracking algorithms will continue to move at the angular velocity that the target had JUST BEFORE it dissappeared behind the cloud. The system is not actually tracking anything.

Edited November 21, 2009 by Speed_2

[Speed_2]

Frederf, do we know of any IR missiles that purposely have a LOAL mode built into them? It's an interesting concept. I do not believe that the seeker heads on older missiles using a scanning IR system would have a large enough field of regard to reliably LOAL, maybe I'm wrong on that, but for sure, some of the new staring focal plane array systems should have a better chance of pulling that off reliably. I think I've read stories of Sidewinders (9Ms are scanning IR systems) locking on after launch, but it seems more like a freak accident kind of thing.

 

Anyway, yea, that's a cool concept for getting around a thick layer of clouds, or even, defeating moderate fog by getting closer to the target and locking on when it finally becomes trackable. Your missile would have to be carefully fired for its initial unguided phase so that the target was right in front of it when it could finally acquire it though- or it could have radar and datalink-based guidance to dependably put the target right in front of it when the seeker got into tracking range. Isn't that how the R-27ET (you know, the IR-guided Alamo) works?

Edited November 21, 2009 by Speed_2

[BaD CrC]

Speed-2. I know my English is somewhat approximative, but if you took time to read my last answer, you would have noticed that I aggree on most of your points. If you are that desperate to justify your job, please feel free to keep posting, I won't interfere with your great science anymore as I feel I lost enough time on this.

BTW, I understand better your signature now.

[Speed_2]

Speed-2. I know my English is somewhat approximative, but if you took time to read my last answer, you would have noticed that I aggree on most of your points. If you are that desperate to justify your job, please feel free to keep posting, I won't interfere with your great science anymore as I feel I lost enough time on this.

BTW, I understand better your signature now.

 

Perhaps I was a bit harsh, but it appeared to me that you are arguing that simulations are meaningless. Sure they are meaningless if they don't match real life, but they do here, and the Air Force has spent over 20 years making sure they match real life. When I see people, no with little to no experience in a field whatsoever, doubting and ridiculing stuff that is accepted and known science and theory, it generally touches a raw nerve in me. The stupidity of it ticks me off. While you were not exactly doing this, you don't seem to have any experience specific to VERY foggy conditions, and a few of the things you said I know for sure are just not correct, or at least, not EXACTLY correct... there are shades of correctness and incorrectness.

 

BTW, it's no longer my job. In fact, it was only a co-op engineering employment for a year, but I learned more than enough about THIS particular question to answer it with certainty. I also learned that I did not want to work for the government! I turned down their permenent job offer and went into graduate school instead.

 

As far as being arrogant, sure I am. I have too much faith in my deductive abilities and think I know everything. However, ALOT of people are this way and won't admit it or just don't realize it- you probably are this way too. What I'm doing here is simply saying exactly what's on my mind without sugar coating like I do on every other forum I frequent. While there is an amazing amount of very useful information on these forums on how to fly DCS BS (which I DO try to contribute to when I feel I can make a useful contribution), there can also be somewhat of a hostile attitude. I think it's because people here just speak their minds and tell you exactly how they feel.

Edited November 21, 2009 by Speed_2

[Frederf]

Frederf, do we know

 

No I don't but look what Google found! http://en.wikipedia.org/wiki/Umkhonto_(missile)

 

I know the Hellfire has gone through a lot of upgrades to not lose lock and to even reacquire lock is lost, something that was bad in the early models that I think is much better now. Of course that isn't a SAM.

 

It sounds like an interesting area of air defense development, watch some jets inbound on a scattered net of very inexpensive simple search radars and throw up a slew of "maddog" IR SAM through a cloud layer based on predicted flight path. That sounds rather nasty and hard to defeat or even detect before it happens.

[Panzertard]

Quite interesting debate.

In some conditions you can launch, in some you can't. It depends on the factors - as well as the weapons - and the experience of the system and the operator. :)

 

I think you gentlemen can agree on one thing - to disagree with eachother. Fair enough.

Dont let it get personal ;)