View Full Version : How do you combat FLIR sensors?

1 July 2000, 01:49
FLIR sensors are used by the police over here to find people lost out in the bush and are also used to find police suspects so I assume that the military use them as well, to find snipers or soldiers. How can you stop such sensors from finding you?

1 July 2000, 09:18
Use a lot of smoke, preferably WP/RP based.
Or preferably get a terrain feature between you and the sensor.

LRSC Grunt
1 July 2000, 13:11
If possible try going subsurface(below ground level) and use a well camoflauged thick space blanket to cover it. This will mask some of the body heat.

Use smoke???????

Ya that sounds real tactical when your trying to hide.

"Hey george, maybe hes behind that big cloud of smoke?"

[This message has been edited by LRSC Grunt (edited 07-01-2000).]

1 July 2000, 14:18
Have you ever head of SOSRs, The best way to hide is a get behind a terrain feature, if you have to absolute go somewhere like a breach or someone is targeting you, you pop smoke and get on the back side of the smoke that way instead of having a small aim point they now have a very large aim point. It is not unusual to do 1000-1500 meter smoke screens if your working with mech. Yes, the enemy knows basically where you are, but instead of being able to pick off individuals or vehicles he can only shoot into the smoke, when smoke is used properly you reduce casualties over 80 percent.

1 July 2000, 16:09
Now this is your field 0802!

LRSC Grunt
1 July 2000, 16:50
Well from my point of view, which is from a hide site 150 miles forward of friendlies. If the mission isnt compromised and the enemy is using counter-recon(such as FLIR), the best thing to do is to stay put. If the hide site is constructed properly it will mask my thermal image. My experience is limited with FLIR, I havent seen it used stalking someone on the run which is what your example is stating(sorry about the misunderstanding on my part). However, If Im subsurface and see a bird with FLIR, I dont throw a smoke. I can see it being used if the mission was compromised and im running for my life.

[This message has been edited by LRSC Grunt (edited 07-01-2000).]

1 July 2000, 19:32
I use FLIR and sensors (IR, magnetic and seismic)to look for humans everyday. Haven't experimented with smoke though but I would imagine it wouldn't help against FLIR very much. Brush will hide you but a depression or a ditch works best. Haven't seen a space blanket on the screen yet either. What the hell, I'll try it this week sometime and see what happens. Got me curious now. I'll post back after I've had a chance to try it and let you guys know. Also, no such animal as a FLIR sensor. Two different things. FLIR is passive and detects heat signatures. An IR sensor projects a beam of light in the IR spectrum that cannot be seen with the naked eye. When the beam is broken the sensor goes off.


1 July 2000, 19:33
Many years ago my unit did a test using FLIR and other thermal imaging against 2 man teams.

A regular ghillie suit work well except for finest settings on the sites. Obviously the more you can wear the less detectable you will be.

1 July 2000, 20:22
Back in the 1990 they did the study of artillery effects here at Fort Sill, in that they set up thermal imagers and experimented with all kinds of smoke to see up much was required to prevent viewing, the big impetus was the growing threat of thermal imagers on Russian tanks and ATGM. They even did some weird things like adding metals, such as gold and silver to the smoke to see how effective those would be in preventing observation. It really depend on the type and quantity of smoke fired. In the fire direction solution a FDO would only have to refer to either his ST-6-40-2 or FM 6-40, there are tables on required amounts of smoke for both visible and IR. A single M18 or HC grenade won't do much, a M34 (if you get far enough away from the smoke cloud, WP being poisonous and all) will screen a 10-20 m area for up to 30 sec under standard conditions until the air cools down. In order to deny an enemy with thermals a view of your unit you can anticipate to shoot 1.5-2 times as much HC smoke, M825 and standard WP expenditure rates would be almost the same as if attempting visible wavelength screening/obsuration.

[This message has been edited by 0802 (edited 07-01-2000).]

LRSC Grunt
1 July 2000, 20:47
Try it using a the thicker type of space blankets not the cheep survival kit type. Set it up like a ground level hooch most preferably over a ditch or hole(to give space between the blanket and the heat source) with the metallic side facing down. From what I was told the only signature it will have is minimumal comming out from the sides.

1 July 2000, 23:04
Thought Iīd share my experiences with hiding FLIR with you. Since we got the Combat Vehicle 90, we have had the opportunity to train against them and since they have thermal imaging we have to hide from that to. Our first experience went straight to hell, half our squads got spotted right away even though we had gone subsurface because of the heat rising from our OPīs. Then we got our heads together and figured out a way to hide even from thermal and tried some of the ideas. The one that worked best without having to bring extra gear was to cover the OP in thick layers of brush because then the air cools off. When youīre on the move your best bet is to get under groundlevel ASAP, and hope the FLIR operator isnīt paying to much attention because if he is, heīll spot the heat shimmer. One thing that worked very well when the sun was up and you know the enemy was heading your way was to set fire to rocks along a stretch of the treeline with some sort of flameable liquid, because then the huge amounts of heat sources confuse the FLIR operator but of course the flames have to have burnt out when the enemy arrives but since rocks retain heat for very long this isnīt a problem. This was used to great effect by us in an exercise, we heated up a large amount of rocks a few hundred meters from our OP and when the enemy arrived they attacked the heat sources with Mech Inf and when they had dismounted to engage we called for artie with coordinates and all prepared, result: one Mech inf comp destroyed(reduced below combat efficiency) and we sneaking out without a single loss http://www.specialoperations.com/ubboard/smile.gif
Note that this usually only works with Mech Inf: FLIR operator:"Sir,I got several heat sources", CO: "Lets kill it!"

Fight smart not hard, the point isnīt to die for your country, its to make the other guy die for his.
Very interested to see what Sharky comes up with.

Videre Non Videri

2 July 2000, 00:34
so from what i gathered so far, you can cover yourself with a space blanket and jump into some kind of thick brush and wait for the vehicle with Flir to pass, or you can confuse by heating anything around you.
does covering boulders and rocks with PE4 and lighting it sound like a good idea?

2 July 2000, 02:49
Thanks guys you helped me alot. I really didnt expect so many replies.
Cheers mate.

2 July 2000, 16:35
Excellent thread so far.

I haven't had the benefit of actually getting to play with FLIR, but my instructors (who have been known to be wrong before) taught that regular Canadian issue cam nets can be used to disperse thermal signatures. Cover from aircraft mounted FLIR supposedly can be acheived by mounting the cam net a few feet above the OP, vehicle, person etc. Theory is that the net is far enough away that it won't get heated up itself, by still is able to disperse the thermal signature.

Is this correct?

Also, does anyone have any URL's for the theory behind FLIR so we can get some hard data on how the system works and hence, how it can be defeated?

5 July 2000, 08:19
Hi guys, haven't forgotten about it but just got put on an undercover assignment for 3-4 months. I'll get one of the guys running our FLIR units to give it a whirl and see what we can come up with. I'll let you know ASAP. RLTW Sharky out...........


26 August 2000, 18:07
A lot of interesting methods here! The basic rule of thumb we are taught if you are using a forest or a building of some sort, is if you can see outside of it from your position, you will be visible to TI. In that case, what you need to do is put two layers between your object (vehicle, hide, OP) and the outside world which will trap an air layer which will remain cool. This gap should be at least 30cm thick. We use two ponchos stretched over one another. Cam nets work, kind of, but only to disperse, and not really to conceal. I'd be interested to hear your opinions.

26 August 2000, 18:10
A lot of interesting methods here! We use this kit quite a lot from our static OPs. The basic rule of thumb we are taught, if you are using a forest or a building of some sort, is if you can see outside of it from your position, you will be visible to TI. If that is case, what you need to do is put two layers between your object (vehicle, hide, OP) and the outside world which will trap an air layer which will remain cool. This gap should be at least 30cm thick. We use two ponchos stretched over one another. Cam nets work, kind of, but only to disperse, and not really to conceal, the problem here being that a really sensitive sensor (or one relatively close by) will pick up your signature through it. Hope this helps, I'd be really interested to hear your opinions.

7 October 2000, 12:01
Anybody heard anything about optical lens detection systems?

Honestas supra omnis

17 October 2000, 18:36
We use a form of thermal imager for the fire service. If military forms are similar, smoke will be of very, very limited value. The one thing I encountered which stymied my handheld FLIR was a water mist sprayer used to cool a restaurant patio during the summer. The fine mist evaporating really made objects within difficult to discern.

17 October 2000, 18:38
We use a form of thermal imager for the fire service. If military forms are similar, smoke will be of very, very limited value. The one thing I encountered which stymied my handheld FLIR was a water mist sprayer used to cool a restaurant patio during the summer. The fine mist evaporating really made objects within difficult to discern.

17 October 2000, 21:29
That makes sense. I didn't think smoke would help much unless it was HOT smoke. Still need to try that space blanket thing though and see if it works.


20 November 2000, 15:11
[This message has been edited by PMI (edited 11-20-2000).]

20 November 2000, 15:12
One of the "commercial" ghillie manufactureres Custom Concealment Inc. claims that they have a ghillie that's optimized to defeat thermal imaging...
http://www.ghillie.com/gallery.htm (click on Thermal Images link)

While most of their product pics are of the usual "Hey look! it's a guy in a ghillie suit!" type, this idea at least bears some merit. (Although heat retention may be a problem for the wearer)

Semper Fi

Gunny Hicks
20 November 2000, 15:56
This may be just one of those legendary 'I was there' stories. But I have been told....
One of the Sniper Instructors was challenged to overcome a FLIR while stalking. The Instructor took the task, and was successful. How ?....The way I heard it, he used an unmbrella, just the correct size to mask his bulk as seen from the front, and after camouflaging it, used it to shield his movement as he inched forward. The open umbrella (as I was told the story) was sufficient enough to mask him from detection by a FLIR system.

Now this is an older story, and may have been tried against an earlier style of FLIR. Who knows what would happen if this were attempted against a newer generation of FLIR technology.

29 December 2000, 16:39
Do any of you know of a Special Ops sniper by the name of Todd Bray? He is from Georgia and has been doing it for a long time. He made some pretty impressive shots down at Ft. Stewart before the Desert Storm build up. Supposed to have a pretty impressive reputation. I'm just an old friend trying to locate him if you can help.

Good Shooting,

4 February 2001, 14:50
There are reports that Lebanese militiamen infiltrated Israeli lines by wearing scuba suits; I imagine the neoprene suits which trap in heat. Not certain if the suit retained all the heat, but I do recall something about their body shapes resembling wild pigs in the area, which allowed them to crawl through areas under FLIR observation.

25 March 2001, 17:32
WOW Another great thread on this forum. I think I found a home!

Gunny Hicks

I heard the same story in 1989.

We did an operation to test some of the new technology in 87. I think SCAMP was the unit defending the old POW base in De Luz (sp) canyon. The teams were immediately compromised because they were moving in the open down a draw about 2 klicks from the target.

The lesson learned was treat all operations as if they were being conducted in the middle of the day and the enemy all had high powered binoculars. Cover routes ect. Also use Hessian screens/camo nets etc. for the OP/Hide.

Also remember there is ground radar too. Thermal is the big killer. You need to watch your self on the move to the target. What really sucks is that any bugger with a handheld could be set up any were and watching for you. It is avery dangerous business!

BUT there are toys that can be used to locate thermal viewers so there are options for you to defete them.

The new cammies we are adopting is supposed to help with some kind of FLIR type units.

Semper Fi

[This message has been edited by lavbo0321 (edited 03-25-2001).]

4 February 2002, 18:26
First post, longtime lurker/browser.

The basics of camoflauge apply here just like everywhere else. Just like visual camo (trying to blend visually with your surroundings) you want to blend. Everything on earth , if it's above absolute zero, emits IR at different rates. Many materials also reflect IR. The key to FLIR is beeing able to see the contrast between the rates of emission and reflection. For example, human skin and electrical tape have roughly the same emissivity values. If I recall correctly 97%. Vegetation hovers around 80%.
Sand, plain old topsoil, and gravel somewhere near 75%, 50% and 25% respectively. The key is to blend with your surroundings without altering them (no shit huh?). The best way to do it is to get behind/under what's already there while paying attention to what's around you (stuff reflects IR too). I don't think I'd trust so called IR blocking clothing very much. More on that later. This is almost like the dog thread in that you need to worry more about the operator than the equipment. Confusion works. The rock trick works. Hot sand works. My experience is limited to having a buddy who was a Huey crewchief (I was a 46 guy) take me on a couple of fam flights at CAX and give me a brief class on the basics. The first flight was about 2 hours after sunset. There were several ground elements out and about. It wasn't that easy for me to spot them due to the hot sand around them washing out their shapes. Later ('round 2300) the sand had begun to cool down and they became more visible. A few days later we flew over some Army arty guys that were on one of the ranges. It was about an hour after sunset. They were wearing those fancy night desert smocks. They stuck out like sore thumbs. They were cold compared to the hot sand background. 2 hours later, and they still stuck out like sore thumbs. That's the limit of my experience with FLIR. I doubt any of the aircrews who operate it regularly would be willing to post any in depth info publicly. It might benefit the guys at SSIC to get in touch with one of the HMLA squadrons and arrange for a look at "the other side" of the magic FLIR ball. They can probably make a few training videos for them. I don't think HMX has any FLIR devices but I've been out for 2 years so that may have changed.

Hope the air perspective helps...


Scouting Spud
27 September 2002, 23:21

any further info on this? I am really interested in your results.

28 September 2002, 02:26
We ran a test like this against the TOW section in 1991 outside of "The Thunderdome" out in the Saudi Desert. Bear in mind that this was not true FLIR, but pure Thermal sighting. One 3 man team got within 100 or so yards using nothing more than a poncho suspended from from 2 cammie net poles being held by 2 of the 3 guys. I would NOT call this a tactical method, as the two guys holding the poles were visible for the entire exercise, and all three were standing upright as they approached through open desert.

Others tried using 2 or 3 space blankets, which didn't work once they got within 500 or so yards (I think they would have been spotted much further out, but used terrain to mask themselves) before they were ID'd.

I seem to recall the poncho being sprayed with scotch guard, but that might have just been something they talked about wanting to do, as cans of Scotch Guard were not readly available out there.

Someof the Marines (from STA 3/3?) went and built a hide box out of ponchos and some other on hand items that did mask them completely from the TOW gunners as long as they didn't touch the sides and didn't let it get too hot inside. Same principle would work for FLIR too if the temprature and texture were correct.

I wish that any civilians or wanna-be Rambos reading this who are contemplating trying to outwit the local PD are in for a big suprise if they think that they will pull it off. I have seen guys jump into the water to try to E&E and go totally submerged... Looks really neat on the FLIR screen, like the old footage of a torpedo moving through the water. The short of it is that you WILL get caught, as the PD isn't going to leave your AO until they have your ass in cuffs.

20 October 2002, 16:27
I think everybody is forgetting a very important piece of info flir cant see through glass or plastic(unless you spend a significant amount of time leaning against it and heat it up).And during the day(a sunny day) flir sees even less because plants and rocks retain heat and make a lot of phantom signatures.The space blanket thing does not work.The best way to hide from flir is maintain distance/move at day if possible/and hide behind glass/keep as much vegetation or terrain between you as possible.If you are in an urban situation you can hide behind a window or in a phone booth and be invisible(at least to flir).the glass thing is bes done at night.during the day there is a day tv mode that is just like a video camera that can see through glass,but its useless at night.

20 October 2002, 17:57
M/SGT N. Morris is the one who used the umbrella. I was at a symposium in 2000 and he spoke about it there and the story has been referenced in a couple books.

20 October 2002, 19:37
your sleeping bag works just fine...as a hide.