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The quest for the multispectral Chameleon.

In the 'survivability onion', the term 'do not be seen remains among the top priorities to be able to see another day. compared with air and sea, ground provides many more concealment opportunities, but things nevertheless get more complicated on the move when a human being or a vehicle must merge into a background that may considerably vary. this is true for both visual and thermal spectra, which are the two domains in which ground units must hide.

Ground surveillance radars are obviously an added threat, but their spread is minimal compared to the Mk 1 Eyeball aided by optical enhancements and thermal vision systems, with the latter no longer restricted to vehicles but widely distributed to the soldier on foot in the form of light hand-held units.

Research is working in various directions, although reduced military budgets will certainly have an impact on those programmes as well. One of the fields currently explored is that of nanotechnologies, with the hope of finding materials that could be purposely engineered so that they change properties under the influence of various types of stimuli such as temperature, moisture, electric charge, magnetic fields and so forth.

Thermochromic and photochromic materials that change colour according to temperature or light intensity are already available, but electrochromic materials that change colour under the influence of electricity might well hold the best promises for military applications. This would indeed considerably help to adapt the visual colour of an object to that of the background.

The key factor here is to find a system that is capable of picking a vehicle's background colours and subsequently determining which parts of the vehicle will have to be 'painted' and in which colour - a real feat if the vehicle is in motion if one bears in mind that visual systems, especially in daylight, have a much higher definition than thermal systems.

Between visual and thermal, the latter is definitely the easier client since it involves much fewer variables than the visual spectrum. Research programmes by official agencies seem to be mostly oriented in that direction, while generally speaking the importance of camouflage appear to have been played down by other higher priorities resulting from lessons learned from current operational theatres. This in no way means that the camouflage field has come to a halt, 2011 having brought a wealth of new products both in passive and active domains.

As for available solutions, the recent past has delivered some significant improvements in active thermal camouflage, or to be more precise, in the capacity of a material to match the thermal signature of the background. Reducing the heat signature generated by a propulsion system or rotating elements is paramount to decreasing one's chances of being spotted by an enemy equipped with a thermal imaging system, even if one has to remember that the mean temperature of the vehicle may still not match that of its background, meaning that even a complete cancellation of hot spots might not be sufficient to make the vehicle Invisible'.

One company that has been particularly active in that department in recent years is BAE Systems. In late November 2010 the British Minister for Defence Equipment announced a white paper to be published in spring 2011 that would formalise the Defence Industrial and Technology Policy for the next five years. In that framework BAE Systems launched the Future Protected Vehicle study, with the aim of addressing two main issues: the high number of casualties related to convoy attacks in Afghanistan (over 80% of all American casualties), and the high cost of fuel on the front line (15 to 50 times higher there due to the cost of logistics).

The company studies are aimed at identifying innovative technologies and concepts for short-, medium-and long-term exploitation. The research has pondered over 567 technologies and 244 vehicle concepts, and involved 35 industrial organisations as well as British universities and schools. Some 47 technologies were finally identified as short-term ones, with some relevant to the camouflage and signature reduction world (active thermal management and active visual signature management).

At least one of then has already come to fruition, although it has earlier roots. The Swedish FMV started in the late '90s to be worried about the proliferation of thermal sensors on the battlefield and asked its national industry to co-operate and identify technologies that might reduce vehicle infrared signatures. Initially the system used for pumping heat from the vehicle's surface was based on water, but this solution proved too expensive, too power thirsty and not robust enough. The company thus shifted to a different approach that led to what was is known as the Adaptiv. Developed with a fifty-fifty investment between industry and the Swedish military, it was unveiled at DSEI 2011 in London.

Based on the heat exchange principle, the Adaptiv is physically formed by a series of hexagonal tiles approximately 15 centimetres across, each one working as a solid-state semi-conductor heat pump and linked to the vehicle's computer. In other words, each tile becomes a pixel of a huge screen spread over the sides of the vehicle. Not many details were unveiled and no cables are used to command the tiles, so an induction system might be used.

It is the computer that tells every single tile at which temperature it must be set and manages the power generation to do this end (to individually increase or decrease the temperature of every single tile) and 'thermally sink' the vehicle into its own background. The required temperature, which can differ from one tile to the next, is provided by a thermal camera (which can be the vehicle's own thermal vision system). Once the sensor has analysed the background, it provides the data to the computer, which in turn manages the tiles' temperatures to reproduce the picture of the background.

Interestingly, the pixel array of the system allows it to be use in other modes, deception being one of them when the thermal signature of a totally irrelevant vehicle is purposely displayed. IFF is another option made possible by using the pixels to display an established code sign, or even message.

A tracked infantry fighting vehicle requires around 1500 such tiles, optimised for an observation range of at least 500 metres. Current tiles are rigid but a flexible version is under development for other applications such as helicopters. Refresh time is relatively short and ensures camouflage even with vehicles moving at 30 km/h.

Current Adaptiv tiles also ensure good radar energy absorption and can also be ballistically protected. According to BAE Systems officials the new product will be available in late 2013. A visible spectrum camouflage system, which might be based on visual film technology over panels, could be available three years later.

Another company that is finalising the development of an active thermal signature camouflage system operating along the same principle is Eltics of Israel. Known as the Black Fox, this adaptive multi-spectral stealth technology can be used in land and naval applications. It comes in the form of panels affixed to a vehicle and linked to electronic control boxes. The latter are connected to two panoramic cameras that provide a 360 thermal scan around the vehicle. This allows the electronics to reproduce the thermal picture on the panels and thereby blend the vehicle into its background, even on the move.

Each panel is made of multiple parts, sort of pixels, each of them linked to a digital processor that sets the right temperature within the 3-5 and 8-12 pm spectral ranges, typical of thermal imagers. Full blending is just one mode, though others allow mimicking a different vehicle using data stored into a database or display reconnaissance symbols or numbers.

Eltics has demonstrated that a Land Rover protected by three panels could 'disappear' into the landscape (when watched through a thermal imager, of course). With a view to improving integration with vehicles the company teamed with Israel Military Industries in 2010 to eventually merge the Black Fox with armour packages and obtain what is termed Invisible Reactive Armour Protection.

PAINTS

Shifting to passive camouflage, Armorworks developed a three-dimensional system known as the Tacticam 3D that appeared on a Stryker at both AUSA 2010 and Idex 2011 exhibitions. Not many details were unveiled except that the new 3D skin irregular pattern coupled to the material used allows a considerable reduction in thermal and radar signatures.

Panels are obviously painted in camouflage colours to cover the visual spectrum, using the company's Opticam system that allows to rapidly create a camouflage pattern that adapts to the surroundings, basing the pattern on hyperspectral pictures of the scenario. The system comes in rigid 3D plastic panels that are installed over the armour. The specific weight of the panels has not been revealed but defined as 'lightweight'.

If panels with different optical camo are available the vehicle can quickly shift its outer skin without having to be repainted. The Tacticam 3D is still under development and was considered at TRL-5 in February 2011. Moreover, Armorworks also developed a spray paint that is said to reduce infrared signature to nil, but no details were made available on this product.

Another paint specialist, Intermat of Greece, is actively marketing its Chameleon series of Low Observation Paints (Lop) -Low Emissivity Paints (Lep). In most oil-based and conventional paints 90% of the possible heat radiated is emitted from the platform's surface. Chameleon paints aim to equalise the target's optical and thermal/IR signature with that of the background, merging shapes and images in an image devoid of operational interest. This result is obtained by merging the higher reflectance of the target with the lower one of the background. Not much information has been provided by Intermat about its paint, which is proposed not only for vehicles but also for static installations to reduce their thermal signature and thereby impair the lock-on performance of some potential threats. Intermat also produces radar absorbent paints.

A company specialised in radarabsorbent coating is Micromag of Spain, which uses a specific metallic fibre capable of absorbing electromagnetic waves. According to the company a 45-metre vessel painted with its product would have a radar signature equivalent to that of a four-metre-long boat. The company demonstrated its products at Nato level and has been actively dealing with the Pentagon, although nothing is being said about a possible contract.

Over the past few years Saab Barracuda has considerably evolved its Mobile Camouflage System, adopting a system concept that provides signature reductions in the spectrum required by the user. The MCS is usually made of five to seven different layers of materiel. Continuous R&D efforts have allowed the company to improve radar and thermal performances while making the materiel lighter.

The 3D configuration is maintained, as this is according to Saab Barracuda the best solution to ensure thermal and radar signature reduction as well as better cooling when integrating the company's Coolcam heat reduction system (to decrease the effects of sun radiation into the vehicle). Colours as well as near-IR values can be adapted to the environmental conditions in which the customer plans to operate. The MCS ensures protection against thermal imagers and heat-seeking missiles but also reduces electromagnetic reflection making lock-on by radar homing missiles operating in the 1-100 GHz band pretty difficult.

Saab Barracuda plays on materials, particles, pigments and the position of the different layers within the camouflage package to obtain the desired effect. The MCS multispectral system is currently used on more than 4000 vehicles around the world, many of which are serving in Afghanistan.

Originally developed to ensure the camouflage of mine and IED-clearing vehicles such as the Souvim, MBDA's Multisorb lightweight synthetic fabric is starting to find new applications. Developed a few years ago under a requirement from the French DGA, the fabric is a passive camouflage that reduces signature in three domains, namely visual, infrared (in bands I, II and III) and radar (typically in the 4 to 100 GHz band).

The Multisorb comes in the form of an outer ventilated three-dimensional structure applied onto a conductive mesh and then mounted onto a foam base. It is available in sand, European and snow camouflage, its thickness varying between 50 and 100 mm while its specific weight is in the 1.5 to 3.0 kg/m2 range, depending on specifications.

The Multisorb's camouflage properties are attracting special forces, with French units testing them on Panhard VBLs (and they seem very satisfied since the materiel on test was not sent back to the company and is still being used). At least one other major European special forces unit is known to be testing the Multisorb in very harsh conditions and a contract is awaited before year-end. A special force unit of a Far East country is also testing the MBDA material and amphibious forces of the same country have also expressed their interest.

MBDA is also promoting the Multisorb as a radar and infrared absorption solution for fast attack craft although simple maintenance rules must be observed when used in a salt-water environment. A major Middle East country is considering the Multisorb to impair the lock-on capabilities of certain anti-tank missiles (more specifically to avoid positive identification and lock-on until the vehicle is within weapon range of the enemy system).

Another company involved in the camouflage business is Blucher Systems of Germany, which recently introduced a new reversible camouflage tarpaulin for use as weather protection in desert or snow areas, the two sides having sand or white colour camouflage. The sand side features a textile surface that traps small particles of airborne sand to further enhance the merging effect of the tarp in the local colouring. The multiple-layer camouflage also ensures maximum effectiveness against thermal imagers. The Blucher system is made of a lightweight materiel, a five x five-meter tarp weighing a mere 20 kg.
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Title Annotation:Camouflage
Author:Valpolini, Paolo
Publication:Armada International
Date:Apr 1, 2012
Words:2303
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