a deadly game of hide and seek

However, in today’s battlefield, simply hiding from human eyes is not enough. People and kit are carried away by signals beyond the visible spectrum, and equipment that detects these wavelengths is getting better, lighter and cheaper. Thermal sensors are a case in point. Today, which costs about $1,000 and weighs as little as five sachets of sugar, can detect a hot vehicle 10 km away, in good weather.

According to Hans Karis, deputy head of Signature Research at the Swedish Defense Research Agency, this is well beyond the range at which a small drone would be observed. Two decades ago, he says, a less sensitive thermal sensor weighing one kilogram would have cost ten times as much.

For those willing to go unnoticed by the forces in Ukraine, the challenge isn’t just that precise sensors are multiplying, on the ground, in the sky and in orbit. It’s also that better automated target-detection software is helping operators find needles in the haystack of data being collected.

look outside!

For example, software called Kestrel, developed by Sentient Vision Systems of Melbourne, Australia, scans a feed of visual, infrared and radar data, and places red boxes around people and other potential targets, even as their position in the frame moves. Are. Sentient says Kestrel has been deployed on more than 3,500 crewed and uncrewed aircraft since its introduction in 2009. Contextual data processing, which classifies objects and calculates ranges, can be done above – a bonus, more data can be collected for an aircraft. be streamed to computers on the ground.

As observed by Maxim Zarazhevsky, an analyst at Molfar, an intelligence firm in Dnipro, Ukraine, the fighting in his country shows how these advances have made it much harder to hide military assets. This undoubtedly helps to explain why, according to Mr Zrazevsky, the Russian military in Ukraine has been using wooden sections to disguise military refueling vehicles as civilian logging lorries. Although it may sound clever, there’s a rub. The 1949 Geneva Convention on War banned the “pretense of civilian, non-combatant status”, as Article 37’s “prohibition of pretense” puts it.

But there’s a different, more traditionally-tailored approach to reducing the chances of appearing in the enemy’s cross-hairs. Instead of making the targets appear civilian, design special camouflage that deceives electronic sensors as well as the human eye.

One developer of such “multispectral” camouflage is Saab, a Swedish industrial giant. Its Barracuda unit sells camouflage netting for vehicles and troops that reduces both radar reflections and heat signals. To handle the radar, it has a specially designed (but secret) layer of smoke. Semi-conducting polymers that absorb a portion of the incoming beam. That prevents reflections that reveal tanks and other military gear. The polymer is difficult to formulate, says Johan Jersblad, a senior camouflage engineer at Saab. If it is too conductive, the netting itself will appear on the radar screen and become a target.

The heat-signature reduction of the Saab’s net comes from an insulating material, also of undisclosed composition, that shields infrared radiation back toward its source, be it the engine, gun, or body. To better fool soldiers or software scanning thermal imagery, the material also reflects cooler wavelengths emitted by surroundings such as the ground and vegetation – in effect, stealing their temperature from them. The material in question is distributed unevenly to mimic heat variation in the natural world. Dr. Karis believes that today’s multispectral camouflage is only half of the range over which the asset can be seen by multiple sensors.

Multispectral camouflage nets are usually reversible – with a different pattern, chosen from a range that includes snowfield, desert, urban, woodland and the like on each side. The net is not unnecessarily heavy. A poncho called the Noah Lite, developed by Fibrotex, an Israeli firm that supplies the US military, weighs less than 700 grams. Ponchos could be attached to each other, to form a covering for an observation post, or a single one, hanging, could shield a soldier.

Manufacturers keep the price list close to their chest, but the products cost so much that they can only be deployed on the battlefields of Ukraine. For example, Mr. Zarazewski noted that the multispectral netting, called Nakidka, a product of NII Stali, a Russian firm, is typically only used for high-end kit, such as the T-90M tank and mobiles. Iskander missile launcher. Ukraine also lacks multispectral camouflage, says a colonel in Kiev, who prefers to remain anonymous. With insufficient ponchos for snipers and special forces, some soldiers, he says, are attempting to buy their own.

a layered design that isn’t

Other ways to reduce the heat signature of soldiers are being worked on. With money from the US Air Force’s Office of Scientific Research and DARPA, a research agency in that country’s Department of Defense, a team at the University of California, Irvine is designing infrared camouflage by embedding tiny metal flakes in thin sheets of rubber. These sheets can then be incorporated into clothing.

In one design using copper, the flakes are a tenth of a micron thick and a few tens of microns in diameter. They reflect body heat inwards. Another uses similarly shaped flakes of aluminum, with the surfaces wrinkled into ridges. These ridges scatter the infrared emissions in different directions, blurring the shape of the heat source.

Both designs would add an insignificant amount of weight to military fatigue, says Alon Gorodetsky, professor of chemical and biomolecular engineering at Irvine who leads the project. He says the technology could be ready in a few years. He adds that such materials could also be used as insulation for better control of heat flow in electronics.

A different type of infrared camouflage called a “presence modulation” system is being developed for military vehicles by BAE Systems, a British defense contractor, with money from the Swedish Defense Materials Administration. Adaptive, as it’s dubbed, draws power from. A combat vehicle to rapidly cool sheets of hexagonal “pixels”, each somewhat larger than an arm, affixed to it. The temperature of the pixels is individually adjustable.

In “Blending Mode,” Adaptive uses data from the infrared camera to match the temperature of surrounding objects. Operators can also choose between pre-programmed patterns in the image library. As BAE Systems explains, this allows them to make a military vehicle appear in thermal imagery as another object, such as a car or lorry. Some believe this may violate the Geneva Convention’s prohibition of passing-off. (Bae declined a request for an interview.) At any rate, the firm says the technology, which has been demonstrated on the CV90 armored vehicle, could enter production in two years’ time.

Adjustable visual camouflage is also in the works. With €700,000 ($700,000) from the European Defense Agency, a branch of the European Union, a research organization called TNO in the Netherlands has designed battery-powered sniper suits containing about 500 light-emitting diodes (LEDs), each half a centimeter in diameter. , embedded in their clothes. The system uses data from a helmet camera and a light sensor to automatically change the color and brightness of the LEDs to match the wearer’s surroundings. Maarten Hogervorst, a researcher on the project, describes the suit as a “Harry Potter cloak”.

Wilder things, even more worthy of Dr. Hogervorst’s description, are in the pipeline. HyperStealth Biotechnology, a firm in Maple Ridge, British Columbia that has produced some 15,000 camouflage color patterns for more than 50 countries, is now making objects invisible. Its “quantum stealth” system uses a translucent plastic sheet with rows of elongated lenses called lenticules. Gluing two of these sheets together so that the lenticular ridges in one align with the troughs in the other causes destructive interference. It blocks the reflected light from an object. In the background, some transmitting from distant objects, on the other hand closer to the sheets reaching an observer.

The confusion, however imperfect, is staggering. According to company founder Guy Kramer, the system also operates at infrared wavelengths. A national-security agency of the US government, which prefers to remain anonymous, bought the material for testing.

As exciting as these advances are, it remains to be seen which will prove most effective, or even practical, on tomorrow’s battlefield. Sensors are also improving in a way that Dr. Jersblad calls “scary stuff” for camouflage technologists. The threat from radar, for example, which was fairly stable for a few decades, has grown rapidly in recent years. Dr Jersblad points to satellite-based synthetic-aperture-radar (SAR) imagery, supplied to Ukraine by ISI, a firm from Espoo, Finland. This allows users (which include the Armed Forces of Ukraine) to see objects only from orbit and through cloud and even light foliage. Half a meter in diameter. New SAR systems for drones promise higher resolution.

look natural

A greater danger may still be hyperspectral sensors. These use sophisticated data processing to map not only the shape of objects, but also their structure – be it leaves, fabric or metal. Giorgio Licciardi, an expert on collecting hyperspectral data from orbit for the Italian space agency in Rome, says the technique also detects buried anti-tank mines. (The soil above them is usually dry.) Officials have been tight-lipped about the use of hyperspectral data to fight in Ukraine, he and others noted, but no one doubts its role will grow.

Then, what can happen next? In an age in which hyperspectral sensors are identifying materials over wide areas, this will not be enough, says Dr Jærsblad, “Now to look like nature—you have to be nature”. So his lab has acquired a hyperspectral sensor. His plan is to design camouflage systems that incorporate real organic and inorganic materials found in the places armies might fight. © 2023 The Economist Newspaper Limited. All rights reserved.