Military Review

In search of a multispectral chameleon

In search of a multispectral chameleon
Artistic representation of Wraith from BAE Systems with an active camouflage system

In the so-called "survivability matrix", the term "invisible" will long remain among the main priorities. Compared to air and sea, land provides much more camouflaging possibilities, but the matter, however, becomes more complicated while driving, when a person or vehicle must merge with the background, which can vary considerably. This is true for the visible and infrared spectrum, and ground units should be hidden in these parts of the spectrum.

Ground surveillance radars are obviously an additional threat, but their distribution is minimal compared to the Mk 1 Eyeball with its optical devices and thermal imaging systems. The latter are no longer limited to vehicles, but are widely used by dismounted soldiers in the form of lightweight portable devices.

Research is being conducted in various areas, although trimmed military budgets also have a definite impact on these programs. One of the areas currently being studied is the field of nanotechnology, in which they hope to find materials that change their properties under the influence of various types of influences, such as temperature, humidity, electric charge, magnetic fields, and so on.

Thermochromic and photochromic materials, which change color depending on temperature or light intensity, are already available, but electrochromic materials that change color under the influence of electric charges could be the most promising for military applications. They could greatly help in matching the visible color of the object with the background color.

The key issue here is finding a system that can “pick up” the background colors behind the car and then determine which part of the car should be “painted” and what color is the most difficult task if the car moves and if we consider that optical systems, especially during daytime , have a much higher resolution than thermal imaging systems.

If we compare the visible and thermal spectra, then the latter is undoubtedly a more “compliant client”, since it includes significantly fewer variables than the visible spectrum. The research programs of official organizations seem to be mostly oriented in this direction, although, generally speaking, the importance of camouflage systems has been reduced due to other higher priorities that have emerged from lessons learned in current theaters of military operations. This hardly means that the “camouflage sphere” has fallen into decay, each year brings an abundance of new products in the passive and active spheres.

As for existing solutions, in the recent past there have been some significant improvements in active thermal camouflage or, to be more precise, in the ability of a material to match the thermal signatures of the background. The reduction of thermal signatures created by a propulsion unit or rotating elements is a primary task, the purpose of which is to reduce the likelihood of being detected by an adversary using thermal imaging systems. It should be remembered that the average temperature of the car may still not coincide with the background temperature, that is, even the complete elimination of hot spots is not enough to make the car "invisible."

The company BAE Systems for the first time at the DSEI 2011 exhibition showed the Adaptiv active thermal camouflage system installed on the CV90 prototype

The close-up of the active thermal camouflage system Adaptiv from BAE Systems also states that it helps to reduce radar signatures.

An interesting solution for camouflaging Adaptive military equipment from BAE Systems with Russian subtitles

In recent years, BAE Systems has been particularly active in this area. At the end of November 2010, the British Minister of Defense Property announced the publication of an official government document in the spring of 2011, defining policies for the defense industry and technology for the next five years. In this regard, BAE Systems began work on a prospective protected machine (Future Protected Vehicle) to resolve two main issues: a large number of losses associated with attacks on convoys in Afghanistan (over 80% of all American losses) and the high cost of fuel at the forefront (in 15 - 50 times higher due to shipping cost).

The company's research is aimed at identifying innovative technologies and concepts for short, medium and long-term use. This study examines more than 567 technology and 244 machine concepts, and is involved in 35 industrial organizations along with British universities and schools. In the end, about 47 technologies were identified as short-term, some of them were related to camouflage and signature reduction (active management of thermal signatures and active management of visual signatures).

Tacticam 3D, developed by Armorworks, is a lightweight flat panel mounted on top of the armor machine

At least one of them is already quite mature, since it appeared much earlier. The Swedish Defense Property Authority, at the end of the 90s, began to worry about the proliferation of thermal sensors on the battlefield and asked the local industry for cooperation and to identify technologies that could reduce the infrared signatures of the machine. Initially, the system of heat removal from the surfaces of the machine was based on water, but was recognized as too expensive, too energy-consuming and not sufficiently reliable. Thus, the company switched to another solution, which led to the system known as Adaptiv. Developed with equal equity participation of the Swedish industry and the military, the system was shown in London at DSEI 2011.

Based on the principle of heat exchange, Adaptiv physically consists of hexagonal tiles approximately 15 cm across, each tile works as a solid-state semiconductor heat pump and is connected to a computer machine. In other words, each tile becomes a pixel on a huge screen stretched across the sides of the car. Little details are known about the system; no wires were used to control the tiles, and therefore an induction system could be used.

The computer indicates to each individual tile what temperature should be set and controls the energy production to obtain such a temperature (individual increase and decrease in temperature of each individual tile) and then “thermally immerses” the machine in its own background. The required temperature, which may differ from one tile to another, is provided by a thermal camera (which may be part of the machine’s own thermal imaging system). As soon as the camera (sensor device) has analyzed the background, it provides data to the computer, which in turn controls the temperature of the tiles that reproduce the background image.

It is interesting that the array of points of the system allows using it in other modes, for example, in the imitation mode, when the thermal signature is intentionally shown in a completely “irrelevant” machine. Another mode of operation of the system is the recognition of “friend-foe”, pixels (tiles) show a certain code mark or even a message.

Tracked BMPs require about 1500 such tiles optimized for an observation distance of at least 500 m. The current tiles are solid, but a flexible version is being developed for other applications, such as helicopters. The update time is relatively short and guarantees camouflage even on vehicles moving at 30 km / h.

Modern Adaptiv tiles also guarantee good absorption of radar energy and can also serve as ballistic protection. According to BAE Systems, the new product will be available at the end of 2013 of the year. A visible spectrum camouflage system, which could be based on film technology over panels, may become available in the next three years.

Another company completing the development of an active thermal camouflage system operating on the same principles is the Israeli Eltics. Known as Black Fox, this adaptive multispectral stealth technology can be used in land and sea applications. It comes in the form of panels attached to the machine and connected to the electronic control units. The latter are connected to two panoramic cameras that provide thermal scanning on 360 ° around the car. This allows electronics to reproduce the thermal image on the panels and thereby mix the car with its background even while driving.

Each panel consists of many parts, a kind of pixels, each of which is connected to a digital processor, which sets the desired temperature in the spectral ranges typical of 3 - 5 and 8 - 12 microns thermal imagers. Full merging with the background is one of the modes, other modes allow you to simulate other vehicles using data stored in the database or show intelligence characters or numbers.

New Black Fox vehicle disguise system from the Israeli company Eltics with my subtitles

Eltics has demonstrated that Land Rover, protected by three panels, can "disappear" in the landscape (of course, when viewed through a thermal imager). In order to improve vehicle integration, 2010 teamed up with Israel Military Industries to combine the Black Fox system with armor kits and get the so-called Invisible Reactive Armor Protection.

The Armorworks Tacticam 3D system is shown on the GDIS Stryker machine. The system is designed to reduce heat and radar signatures.

Image of a building in a thermal imager: BIack HOT (1), Purple HOT (2), Red HOT (3)

Greek company Intermat also offers special paints for buildings in order to reduce vulnerability to IR-guided missiles.


As for passive camouflage, Armorworks developed a three-dimensional system under the designation Tacticam 3D, which was presented on the Stryker machine at the AUSA 2010 and Idex 2011 exhibitions. Few details were revealed except for the fact that new chaotic 3D images applied to the material significantly reduce thermal and radar signatures.

Obviously, the panels are painted in camouflage colors to cover the visible spectrum with the help of this company's Opticam system, which allows you to quickly create a camouflage pattern adapted to your surroundings based on the hyperspectral pictures of the battle scenario. The system comes in the form of rigid 3D plastic panels that are installed on top of the armor. The specific gravity of the panels was not made public, but was defined as “light”.
If panels with different optical camouflage are available, the machine can quickly change its outer shell without repainting. Tacticam 3D is still at the development stage and in February 2011, it was assigned the level of technological readiness 5. In addition, Armorworks has developed spray paint that reduces the infrared signature to zero, but the details on this product have not been made public.

Another specialist in coloring - the Greek company Intermat - is actively promoting to the market its series of low visibility paints Chameleon (Low Observation Paints (Lop)) - low emissivity (Low Emissivity Paints (Lep)). For most oil and standard 90 inks,% of the possible radiated heat is emitted from the surface of the platform. Chameleon paints are designed to align the optical and thermal / IR signatures of an object with background signatures, combining forms and images into a picture devoid of operational interest. This result is achieved by merging a higher reflectivity of the target with a lower reflectivity of the background. Intermat has provided some information (this applies to almost all companies working in the field of camouflage) about their paint, which is offered not only for vehicles, but also for static installations in order to reduce their thermal signatures and, therefore, deterioration in target capture characteristics of some potential threats. Intermat also manufactures radar absorbing inks.

The Spanish company Micromag specializes in absorbing radar coating, which uses special metal fibers that can absorb electromagnetic waves. According to the company 45-meter vessel, painted with its colors, will have radar signatures equivalent to the 4-meter boat. The company has demonstrated its products at the NATO level and is actively cooperating with the Pentagon, although the possibility of a contract is not mentioned.

In the past few years, Saab Barracuda has significantly developed its mobile camouflage system, the MCS (Mobile Camouflage System), adopting a system concept that reduces signatures in the spectrum required by the consumer. MCS is usually made of 5 - 7 different layers of material. Constant research and development has allowed the company to improve radar and thermal performance while reducing the mass of the system.

The 3D configuration is preserved because, according to Saab Barracuda, "this is the best solution to guarantee a reduction in thermal and radar signatures," as well as providing better cooling when installing the Coolcam heat sink system (reducing the effects of solar radiation on the machine). Colors, as well as the values ​​of the near-IR spectrum, can be adapted to the external conditions in which the user plans to act. MCS guarantees protection against infrared imagers and rockets, as well as reduces electromagnetic reflection, making the capture of radar homing missiles operating in the 1 - 100 GHz range very difficult.

To achieve the desired effect in the camouflage kit, Saab Barracuda plays on materials, particles, pigments and the position of different layers. The multispectral MCS system is currently used on more than 4000 machines around the world, many of them serving in Afghanistan.
Originally developed for camouflage clearance machines (for example, Souvim), MBDA lightweight synthetic fabric from MBDA is beginning to find its application in all new applications. This material, developed several years ago at the request of the French Defense Procurement Agency, is a passive camouflage that lowers the signature in three bands: visible, infrared (bands I, II and III) and radar (usually in the 4 - 100 GHz band).

Multisorb fabric comes in the form of an external ventilated three-dimensional structure applied to a conductive mesh and then installed on a foam base. The fabric comes in camouflage of three types: for Europe, sand and snow. Its thickness varies from 50 to 100 mm, and its specific weight is in the range 1,5 - 3,0 kg / m2, depending on the specification.

The properties of the Multisorb camouflage attract special forces. French units test them on Panhard VBL (and, apparently, are very satisfied, because the test material is not sent back to the company, but is still used). It is known that at least other large special forces from Europe tested Multisorb in very harsh conditions and as a result several contracts were signed. The command of the special operations forces of one of the countries of the Far East is also experiencing material developed by the MBDA; moreover, the amphibious units of this country also showed their interest in this camouflage.

The CV90 BMP operating in Afghanistan is equipped with the Saab Barracuda multispectral MCS system. This system is currently installed on more than 4000 machines.

The figure shows how MBDA's Multisorb reduces thermal radar and visible signatures. The system has already found its first customer.

The Multisorb system developed by MBDA is shown on the VBL machine of the French army. Its specific gravity varies within 1,5 - 3 kg / m2

MBDA also promotes Multisorb as a radar and thermal radiation absorption solution for high-speed boats, although simple maintenance rules should be followed when operating in salt water. Major Middle Eastern countries are considering the acquisition of Multisorb in order to reduce the possibility of target seizure of some anti-tank missiles (in a narrower context, avoid positive identification and target seizure while the machine is within the range of the enemy weapons system).

Another company involved in the camouflage business is the German Blucher Systems, which recently introduced a new two-sided camouflage tarpaulin for use as weather protection in desert and snow-covered areas, the two sides have sand or white camouflage. The sandy side is distinguished by a textile surface that captures small particles of sand wearable in the air to further enhance the effect of merging the tarpaulin with local colors. Multi-layer camouflage also guarantees maximum performance against thermal imagers. The Blucher system is made of a lightweight material; tarpaulin sizes 5 on 5 meters weigh less than 20 kg.

Materials used:
Armada International
Dear reader, to leave comments on the publication, you must sign in.
  1. mirag2
    mirag2 April 9 2014 08: 53
    The Poles showed the concept of a new tank jointly with BAE, "invisible" with these developments, right?
    1. maks-101
      maks-101 April 10 2014 11: 43
      A promising concept announced by Obama is the creation of teleporters for the transfer and evacuation of equipment. It’s just that bureaucrats and a business man need to eat, 90% of such projects are cut military budgets.
  2. wanderer_032
    wanderer_032 April 9 2014 09: 01
    The material is interesting and informative, but no matter how Western engineers would not be perverted in protecting and disguising their BM, for some reason, uncles with improvised HE mines and RPG-7 still knock them down.
    By the way, thermal imagers are not widespread in our army, but all sorts of cheap and effective anti-tank gizmos are simply heaps. There is also something more serious and already in iron, or else it will be.
    We always have a cheap and effective answer against expensive, complex and inefficient systems. wink

    1. wanderer_032
      wanderer_032 April 9 2014 09: 07
      Oh time, yes again ...
      A bit more. bully yes

      1. wanderer_032
        wanderer_032 April 9 2014 09: 24
        And there are mines ...

        Means for the mechanized installation of min.

        1. wanderer_032
          wanderer_032 April 9 2014 09: 27
          So disguise yourself, don't disguise the way we will always find.
          That's it. yes
          And the result will be like this:

          1. wanderer_032
            wanderer_032 April 9 2014 09: 32
            Continuation of the end ...

            Here is what awaits those who turn to us.
    2. sim6
      sim6 April 9 2014 09: 53
      That is true, but it would not hurt for us to have our own developments in this area, even in a battle with RPGs, it will help, the contours of the combat vehicle are blurred, it is more difficult to focus on the target in the heat of battle
      1. Constantine
        Constantine April 9 2014 10: 55
        If they are not spoken about on every corner, then this does not mean that they are not. For obvious reasons, these things are best kept secret for as long as possible. In this case, the enemy will be misinformed about the real state of things, which as a result will give us an advantage. smile
        1. cosmos111
          cosmos111 April 9 2014 11: 40
          Quote: sim6
          even in battle with RPGs will help, the contours of the combat vehicle are blurred, it is more difficult to focus on the target in the heat of battle

          and if you act, at night ????
          then, thermal imagers come to the fore !!!!
          here, from them we must mask our technique (((
          and just, camouflage has not yet been canceled (((
          camouflage set "Cape" -development of the Research Institute of Steel (((
          the probability of its detection by night devices and sights, thermal imaging systems and homing heads is reduced by 30%, infrared seeker is reduced 2-3 times !!!
          1. wanderer_032
            wanderer_032 April 9 2014 12: 44
            Welcome all hi
            Here is a video on the RPM "Cape" I found.

      2. BEECH 1972
        BEECH 1972 6 June 2017 09: 51
        We also have similar developments. There are even more others, at least not worse than those presented. ;-) Nevertheless, in the polar and arctic regions, a specially developed masking completely hides equipment with running engines, dugouts or command posts from visual thermal imaging means of detection. But all this camouflage is effective only in the parking mode BT or car. Any energetic movement will immediately give out your technique with your head.
    3. postman
      postman April 9 2014 11: 29
      Quote: wanderer_032
      for some reason, uncles with homemade land mines and RPG-7 still knock them down.

      and what does disguise have to do with "knock down"?
      What does camouflage resistance affect?
      What would "uncle knocked off" must first be discovered, and this with disguise to make a problem
      Try to "discover" it

      Anti-Nightvision camouflage "Ghost" camouflage technology by german company Texplorer GmbH (Now Blücher Systems GmbH)

      whoever saw before won
      1. The comment was deleted.
      2. self-propelled
        self-propelled April 9 2014 11: 54
        Quote: Postman
        What would "uncle knocked off" must first be discovered, and this with disguise to make a problem
        Try to "discover" it

        and here we are! smile
        1. postman
          postman April 9 2014 12: 07
          Quote: self-propelled
          and here we are!

          it would be good.
          I found Finns in camouflage when they stopped ...
          / Apparently for the reason: there were no sledgehammers with you ....
      3. wanderer_032
        wanderer_032 April 9 2014 12: 52
        Quote: Postman
        and what does disguise have to do with "knock down"?

        And such that in addition to visual detection, there are other methods (sound, radar, undercover, etc.).
        And in recent armed conflicts, the coalition forces of the United States and NATO did not carry out a single sudden military operation.
        In addition, if you watched a movie about mines, then they talked about TM-72 and TM-89 mines that fire without direct contact with BM.
        In addition, the TM-89 mine is very difficult to defuse.
        1. postman
          postman April 9 2014 14: 03
          Quote: wanderer_032
          And such that in addition to visual detection, there are other methods (sound, radar, undercover, etc.).

          Well, actually I’m for approval
          Quote: wanderer_032
          for some reason uncles with homemade land mines and RPG-7 all the same they are felled.

          1. I don’t really understand how sound, agent and radar will help the "uncle" with RPG-7?
          (maybe I missed something, maybe the RPG is already equipped with an undercover sensor?)
          2.the sound is of course cool ... only now I was at the training ground near St. Petersburg, my hearing is normal, that I found helicopters and tanks (what, where), when I was already "destroyed"
          on the radar (well, the RPG does not have a TsU and TsN radar, as I wrote above) .. Rubber skirts have been used for a long time to reduce the radar signature, which reduce the detection range of equipment by passive radars. Against active- form of equipment and materials
          agents ... I can’t even imagine HOW it’s on the battlefield, and again, how to transfer this information to the "uncle" with an RPG
          Actually, everything is described quite simply. MASKING MOBILE LAND OBJECTS IN MODERN CONDITIONS.

          Quote: wanderer_032
          mine, everyone is good, but it has a SIGNIFICANT drawback - BM must find this very mine (at least drive up to it), the mine does not "look for" BM, it is passive.
          and that which rolls in the mountains of Chechnya or Afghanistan (where there is only one road), then on the plains, in the forest-psssss.
          As an example: HOW many tanks were destroyed during 2MB from MIN?

          Quote: wanderer_032
          In addition, the TM-89 mine is very difficult to defuse.

          Yes, no doubt, there are many ways to destroy BM, but the statement
          Quote: wanderer_032
          but no matter how Western engineers would be perverted in protecting and disguising their
          least (!) Controversial!
          As an example:
          Instinctive aiming (
          Quote: wanderer_032
          uncles with homemade land mines and RPG-7
          ) underway to the geometric center of the target (the middle of the projection of the tower for tanks). If with the help of DE to increase the size of the tower (for example, by creating a false shell-filled recessed niche), then when firing there will be an aiming point that can go beyond the turret’s envelope, which will sharply reduce the tank’s damage when firing from the side.

          Well minuses essno: However, this solution in addition to increasing the dimensions of the tank leads to the possibility of engaging DE for obstacles when moving the tank and turning the turret to the side.
          1. wanderer_032
            wanderer_032 April 9 2014 17: 52
            Quote: Postman
            1. I don’t really understand how sound, agent and radar will help the "uncle" with RPG-7?

            When conducting defensive operations in military units and partisan actions, there is such a thing as working with the local population (this is intelligence agents) and sometimes such information is very useful.

            And knowing that the enemy is using a new (previously not used) technique, you can take measures for its "hot" meeting. After all, it is equipped with camouflage devices for long-range visual detection and for detection by thermal imaging devices.
            That is, any normally trained shooter-grenade launcher at a distance of firing from an RPG will be able to detect and destroy, or disable a BM with camouflage equipment of a similar class. It is just useless.

            About sound detection has been known for a long time, even xp..en knows from what time.
            In addition, you must be completely deaf in order not to hear the approach of a tank or other BM at a distance of starting a grenade from an RPG. Even during the Second World War, the sound of the enemy’s gunshots at long distances determined their location and delivered their fire attack.

            In addition, there are many tactical techniques and methods for setting up ambushes on the movement path of military marching columns and tactical methods of conducting combat against attacking armored vehicles.

            Quote: Postman
            mine, everyone is good, but it has a SIGNIFICANT drawback - BM must find this very mine (at least drive up to it), the mine does not "look for" BM, it is passive.

            You know little tactics. During the Second World War (Kursk Bulge), our sappers managed to plant mines in a very short time before the approach of enemy armored vehicles and very effectively. This was called "cheeky mining".

            Now, specifically about the Chrysanthemum-S ATGM. The radar of this complex uses a high-frequency working range with which you can detect any objects on the ground, and the real size of this object will be displayed on the screen. Thermal protection is useless here, and the quality of Western samples of radio-absorbing coating can be assessed even by the F-117 STELS aircraft, which were shot down with the help of old radars of the KUB air defense complex.

            In addition, we have in service and other radar systems of a similar class.
      4. cosmos111
        cosmos111 April 9 2014 15: 53
        Quote: Postman
        whoever saw before won

        Iraqi T-72 tank, in the gunner's thermal sight "Abrams A1" .....
        1. postman
          postman April 9 2014 16: 45
          Quote: cosmos111
          Iraqi tank T-72,

          Yes ... Well, the result of that war is the same 68 against 380 (or something like that?)
  3. Stiletto
    Stiletto April 9 2014 09: 40
    Yeah The Americans invented and invented a ballpoint pen for working in zero gravity, a million swelled, it was not known whether it was good. Well, the Russians at that time, not particularly bothering, used a pencil. Cheap and cheerful.
  4. Hort
    Hort April 9 2014 11: 17
    BMP CV90 operating in Afghanistan
    and in the photo "Leopard" repeat
    1. The polar
      The polar April 9 2014 12: 01
      It seemed to me that this is Abrams
    2. cosmos111
      cosmos111 April 9 2014 15: 18
      Quote: hort
      and in the photo "Leopard"

      MBT Leoperd 2A5, Danish Army in Afghanistan ...
  5. k_ply
    k_ply April 9 2014 11: 53
    The people have a tendency to confuse anti-tank weapons (such as RPGs and ATGMs with a cumulative warhead) and land mines in tens of kg. and power units "hummer" and MRAP.
  6. Gomunkul
    Gomunkul April 9 2014 14: 17
    In the so-called “survivability matrix”, the term “invisible” will remain among the main priorities for a long time.
    Does anyone know how dust and dirt are removed from these surfaces? And how will dust and dirt affect these surfaces? Such coatings are going to be used in combat in Slovenia, and not at exhibitions. hi
  7. max702
    max702 April 9 2014 14: 20
    All the camouflage solutions in the article are very interesting, but ... all this is lab-production shots, but what if the machine is muddy in mud? how will adaptive tiles work, volume screens, if there is a layer of dirt on them, and the paint is tricky? Or is everything always perfectly clean and they never fight in the mud?
    1. kocclissi
      kocclissi April 9 2014 16: 17
      Tanks? In the mud? Such tanks drive only on asphalt concrete pavement! And so they’re not afraid of mud .....
  8. k_ply
    k_ply April 10 2014 03: 24
    Quote: max702
    All the camouflage solutions in the article are very interesting, but ... all this is lab-production shots, but what if the machine is muddy in mud? how will adaptive tiles work, volume screens, if there is a layer of dirt on them, and the paint is tricky? Or is everything always perfectly clean and they never fight in the mud?

    But can not dirt be an element of the background of the area? In my opinion, one does not interfere with the other, one figs all these cons-consumables
  9. BEECH 1972
    BEECH 1972 6 June 2017 09: 51
    We also have similar developments. There are even more others, at least not worse than those presented. ;-) Nevertheless, in the polar and arctic regions, specially designed camouflage completely hides equipment with running engines, dugouts or command posts from visual thermal imaging means of detection. But all this camouflage is effective only in the parking mode BT or car. Any energetic movement will immediately give out your technique with your head. In the snow, in the mud, or on slightly damp grass, these will be clearly distinguishable ruts. And when driving on dry grass or a dirt road, these will be no less clearly distinguishable dust plumes. Which, if not masked, cannot be hidden either. Even the perfect chameleon as in the Arnoldo Schwarzenegger "Predator", will cast a shadow or glare from certain angles. If the surface is the most ideal light absorber, then a black hole overlapping the background will be clearly visible, even if it matches the background, you will still see a spot different from the overall picture, which can easily be distinguished by both the human eye and a computerized observation system. The latter, for example, even notice transparent balls filled with light gas, with suspended loads of transparent material hanging from them on transparent lines, and they not only notice, but also sound an alarm. In parallel, determining the parameters and dimensions of the observed object, and even tracking the intended route of their movement. Such systems, observing the battlefield, or the attack-hazardous direction, will not only track masked equipment, but also determine its contours, parameters, and even if it has the necessary data in its bases, classify the alleged target as a tank, BRDM, armored personnel carrier or infantry fighting vehicle.