To Survive, Deceive: Decoys in Land Warfare

Editor’s Note: This article has been adapted from a paper in French published in Défense & Sécurité Internationale (DSI).

In a black-and-white photo seen in many books and newspapers to illustrate the deception integral to the D-Day invasion, four men carry a 30-ton Sherman tank near what seems to be a barrack. This famous image is bizarre. Of course, what it shows is an inflatable tank, a decoy that was used in the vast and complex deception operation around the 1944 Normandy landings. Land tactical decoys are dummy equipment like armored vehicles, bridging capabilities, artillery pieces, and radars or installations (buildings, bridges, and runways) intended to deceive enemy observers. Their use has been standard in warfare since ancient times. Among the countless examples, relatively contemporary decoys include the Quaker guns of the U.S. Civil War, which were logs simulating artillery pieces; “horses” made of wood and blankets used by the British at the Battle of Megiddo in September 1918; the construction by Her Majesty’s Sappers of 8,400 dummy vehicles and devices of all kinds for Operation Bertram in 1942; and, more recently, various decoys to deceive enemy aircraft used by the Iraqis in 1990 and 1991, the Serbs in Kosovo in 1999, the self-styled Islamic State group in Syria and Iraq, the Houthis in Yemen, and Armenians and Azerbaijanis in Nagorno-Karabakh in 2020. Unsurprisingly, major potential adversaries of Western countries have kept a place for decoys in their armed forces: China seems well equipped and appears to give decoys a prominent place in its maneuvers, for example, and North Korea is reportedly using decoys intensively to protect its equipment and plans to use them extensively in warfare. Faithful to its longtime military doctrine of maskirovka, or deception, Russia pays special attention to decoys and even has a dedicated unit (the 45th Independent Camouflage Regiment) stationed near Nakhabino in the Moscow region.

Western armies, however, appear to have dropped decoys from their inventories. The main reason is that for too long, they have benefited from “operational comfort” and, in particular, undisputed air superiority during interventions abroad. That has to change if Western armies are serious about preparing for clashes with sophisticated peer or near-peer adversaries that, themselves, not only make regular use of deception and decoys but — more importantly — also have the means to observe and detect their enemies, as the conflicts in Crimea and Donbass in 2014 and 2015 have shown. In the words of Gen. Thierry Burkhard, French Army chief of staff, who is committed to restoring the French Army’s ability to take on peer threats, “For too long, we’ve disregarded the use of ruse. It begins with the tactical maneuver of the company, which must systematically try to deceive the enemy, and it continues with the equipping of our units with decoy means.” Nevertheless, while the value of deception is widely accepted, operationalizing it on the ground has proved difficult.  The challenge is that we have entered an era of “fatal visibility.” Detection means are increasingly powerful. For instance, hyperspectral radars make it possible to detect not only what is visible on the surface but also the nature of the materials and the classification of soils, gases, spectral anomalies, and so on. In domain of the radar imagery, the use of interferometry can detect activity such as the passage of vehicles. In addition, sensors can be equipped with artificial intelligence. Indeed, as more sensor-equipped devices are generating greater amounts of data, AI can be an efficient tool to systematically label, process, and analyze this information. All this, coupled with the ever-increasing size of military units’ electromagnetic footprint — due to their use of, among other things, more and more signal systems, radars, geolocation means, and active protection systems — and a democratization of remote-strike means (including loitering ammunition), makes the use of decoys both more complex and more essential. As it is now harder to hide or camouflage equipment, decoys have become even more important.

Commanders use decoys in a maneuver to attract the attention of the enemy while pursuing a variety of objectives. First, an army can employ decoys to increase the survivability of installations, units, or equipment, primarily in the face of air threat (drones, planes, helicopters) and indirect fire. This is because decoys provide alternative targets and can therefore decrease the adversary’s chance of hitting real targets. They also cause opponents to consume ammunition, a significant effect given the cost of some ammunition and, often, the low volumes stored.

Second, decoys can be used to deceive the adversary, particularly aerial reconnaissance, about the number and location of weapons, units, and equipment. There can be multiple desired effects: to intimidate or dissuade action in a sector; to appear more numerous than is really the case; to replace equipment or service members on the contact line and to make it appear that the real units are still there when in reality they are repositioning; to create a false unit to pose a threat in one direction and thus distract the enemy from the main action; to attract enemy fire to force adversaries to reveal their positions and expose them to fire; and to set up artificial obstacles (decoy improvised explosive devices, mines, etc.) to slow an enemy’s progress or channel an enemy in a particular direction.

Decoys are one of the most effective tools in deception operations. A study by the U.S. Army carried out at the end of the 1980s used Janus, a program capable of simulating a combined warfare up to the brigade level that was developed at the end of the 1970s, to simulate the combat of two armored companies (28 tanks in total) against a Soviet tank regiment. The study found that units equipped with decoys were more efficient, with a 28 percent improvement in their ability to detect opponents due to the enemy’s reactions to decoys. Friendly forces lost 18.3 percent fewer tanks and destroyed 4.5 percent more enemy tanks. This was especially evident when units placed decoys in front of actual tanks but less so when the decoys were deployed behind or among the tanks. This study also concluded that deploying more than one decoy per real tank did not bring better results and, with four decoys for a tank, could be counterproductive because the deception attempt was more obvious to the enemy.

To be effective, the use of decoys should follow a few basic rules. First, it should stick to this equation: A decoy must be less expensive than the equipment it simulates and require fewer materials and less time and effort to set up than the materials than the time and effort it will cost the adversary to detect or destroy it. Therefore, decoys must above all simulate high-value and often less-mobile targets (headquarters, ground-to-air batteries, bridging equipment, etc.).

Second, if the enemy is to be convinced that they are real, decoys must obviously be realistic. It’s not enough for the decoy to look like the object it’s simulating. It also needs to “look” to radar or other sensors like the object, with a multispectral signature as faithful as possible to that of the simulated equipment. For the sake of precision, it is also desirable for each decoy to explode or burn like real equipment — hence the usefulness of adding fire or explosion simulators.

Finally, a high-fidelity decoy is not enough. Its environment must be realistic, too, as deception is “a large-scale movie production.” There are many factors to be consider to ensure that no clues betray the presence of decoys. For instance, the camouflage of decoys’ camouflage must be plausible, meaning neither too effective nor non-existent. The place where decoys are deployed must be realistic, which means, especially, that it conforms to doctrine. It is also essential to ensure a minimum human presence (which is also useful for maintenance of the decoys, such as replacing batteries). Various devices can further strengthen the authenticity of the simulation such as lights, smoke, or even sound devices to broadcast, for example, engine noise.

Beyond the matter of the credibility of the decoy, we must not lose sight of the fact that deploying a mediocre one or failing to set up the “scene” can create an additional risk. An adversary who detects a deception will be more inclined to make a greater effort to find the real target. However, beyond this risk, the use of decoys usually contributes to the success of a maneuver: If the enemy does not suspect that there are some decoys, he can be deceived; if the adversary has knowledge of the enemy’s decoying abilities, he will waste time on checks.

Decoys can be either basic — visual-only or do-it-yourself devices by a unit, for example — or elaborate. The tactical relevance of their design depends in particular on the time and equipment available to the unit and, above all, on the sensors available to the enemy. In fact, given the evolution of detection means, there is a clearly increasing need for more multispectral decoys — dummies of a combat vehicle, for instance, that not only simulate an actual vehicle visual but also its thermal, radar, electromagnetic, or acoustic signatures.

Several companies now offer products of this type, among them Fibrotex (Israel), Rusbal (Russia), Saab (Sweden), Tempestini (Italy), Lubawa (Poland), and Inflatech (Czech Republic and Russia). Their decoys combine the visual appearance (realistic up to a distance of 100 meters for the most efficient) with a thermal signature (by integrating, for example, resistors and conductive fabrics), infrared signature, or even radar signatures. They can be 2D or 3D, inflatable, or made of wood or metal panels. The decoys frequently can be disassembled. Their weight and size vary. For example, an Inflatech inflatable SA-17 weighs 58 kilos (128 lbs) and the T-80 weighs 37 kilos (81.6 lbs). Decoys usually need a truck for transportation, although 10 metal tanks made by the Australian company GaardTech fit, disassembled, in a sea container. There are also models based on a trailer, like the T-72 of the Belarusian company, Minotor-Service, which weighs 3.5 tons and deploys in 20 minutes. The price of a multispectral decoy varies widely but remains affordable. To simulate a main battle tank costs from €30,000 to €150,000 ($36,000 to $180,000). In the end, this is modest compared to the price of a modern tank: In 2001, the Cours des Comptes estimated the overall unit cost of the French Leclerc tank to be €15.9 million ($19.1 million).

We can distinguish four major technological trends related to future decoys. First, with the development and spread of electronic warfare capabilities, the electromagnetic signature of a decoy is essential. Munition-launched electronic warfare systems are another option, for example the Silent Impact, which uses a 155-millimeter munition shell as a delivery mechanism for “cyber-electromagnetic attack” payloads in flight and a parachute to stay aloft for extended periods and on the ground after it lands. This payload can also be employed as a decoy imitating radar and weapons systems and communications. As of today, one of the most effective deceptive courses of action is probably to reproduce the command networks of a headquarters to limit the enemy’s capacities to identify and target the real headquarters. By 2030 or 2040, decoys, possibly air-droppable and capable of replicating the electromagnetic signature of a headquarters or vehicles, may be common.

In addition, land decoys, while traditionally fixed, may be mobile and remotely operated. The advantages are many. Robotic decoys are more readily usable in offensive courses of action because it is easier to get them to move at the speed of the real equipment in the maneuver (adapting decoys’ use to the speed of the maneuver has been a challenge in the past). Also, their mobility will reinforce their realism. Targets reproducing certain signatures and remotely operated from a distance up to 20 km (12.5 miles) using a tablet already exist, such as those made by GaardTech. With a few modifications, these could be used in combat to deceive an opponent.

The third structuring technological trend, in the longer term, is that with the contribution of AI, robotic decoy formations could reproduce the movements of certain units. The GaardTech tablet already makes it possible to move together several targets in training. In the future, an armored column could carry robots and, at some point in its movement, set them on a different route in order to deceive about where it is going to attack. On a general level, it is likely that the frontier between decoys and combat robots will become growingly blurred since robotic decoys would serve both to confuse the adversary and to assault him.

The fourth technological trend concerns the increasingly crucial role that aerial drones should take — and particularly their use in swarms — for tactical decoy, whether it is to simulate a unit or saturate the opponent’s sensors and strike tools (ground and air systems, surveillance networks, operators in charge of interceptions, etc.). For example, one or more drones could reproduce the electromagnetic and radar signature of transport or attack helicopters and thus create the false appearance of a reconnaissance or a heliborne operation. Drones equipped with radar reflectors, circulating on the battlefield and in the rear, could generate multiple false alerts and, in particular, confuse the common operational picture of an adversary.

In addition, we should also point out a promising but not mature technology for decoys: holography. Scientific research is making significant progress with volumetric 3D holograms and other types that emit sounds and can be “touched.” In the longer term, holography would therefore be able to create convincing visual decoys. However, it will first have to become portable and have a sufficiently large display and a suitable resolution.

Finally, as an alternative and complementary option to deceive, it is also possible to modify the visual, thermal, radar, or electromagnetic signature of a vehicle or an installation so that adversaries confuse them with others. This is the model of the 722 “sunshields” that were employed during Operation Bertram”: canopies made of a wooden frame and canvas to visually transform tanks (Crusader, Valentine, Grant, Stuart, and Sherman tanks) into less threatening-looking three-ton trucks. This was also the path taken by the Taiwanese army when it experimented with the transformation of an infantry fighting vehicle into a crane to blend into an urban environment (though camouflaging a military vehicle into a civilian one can be qualified as perfidy). In this spirit, one could imagine equipping certain vehicles with modification kits that would allow them to be transformed into a decoy.

The development of detection and protection systems favors a renewed use of decoys. Indeed, in recent years, to increase survivability, attention has turned to active protection systems to avoid the impact of a potential aggression by neutralizing or deflecting it from a distance. This kind of equipment uses three main types of detectors: radar, passive listening to enemy radars, and laser and missile launch. Since, they must, in a truly short time, detect a threat, classify it, possibly calculate an interception point (for “hard kill” systems), and employ countermeasures, these active protection systems involve extensive automation. This automation of detection and protection offers new opportunities. A visual decoy coupled with a firing simulator (range finder, laser illuminator, or even smokey missile) could make the active protection system react automatically or semi-automatically. Even without really firing at vehicles, this type of decoy would create confusion and result in a loss of confidence in the self-protection systems.

With the planned advent of collaborative combat in most advanced armies, the impact could be even greater. For the French Army, when stage two of the Scorpion program is completed, the collaborative combat concept will mean that a new information system will link armored fighting vehicles (Jaguar, Serval, Griffon, and the modernized version of the Leclerc tank); aviation support units; and artillery batteries in one centralized information-sharing network designed to automatically distribute alerts, targeting information, and other data between vehicles, robots and drones. The goal is to optimize mutual support functions. Part of this concept is based on automatic detection and reactions: A vehicle detecting an aggression should automatically transmit the information to the other ones present in the area. Consequently, the latter could automatically direct its detection and firing systems on the target. The goal is to obtain a collective response in “reflex time.” If a decoy triggers a semi-automated reaction for an entire unit, it could find itself stuck, potentially disorganized, and at the mercy of indirect fire.

In general, the deployment of automated processing (detection, or even automatic or assisted identification, for instance, or fusion of sensors) makes realistic multi-band decoys even more useful. These decoys will provide all the signals that the algorithm expects without any room for the doubt that a human operator might have. The trend toward robotic, multispectral decoy formations further reinforces decoys’ relevance for tomorrow’s warfare and offers new tactical perspectives.

The acquisition of decoys and the monitoring of innovation in this area should therefore be a priority. As such, it might be a good idea to commit to investing — for each weapons program — up to 1 percent of the total cost of developing the weapon to the creation and acquisition of a corresponding decoy. The army should then promote the use of these decoys, writing a doctrine of deception explaining and encouraging their use and deploying them during exercises. Finally, it would be a good idea to create a specialized unit, in particular to bring together less-common decoys (bridges, ground-to-air equipment, and so on) and to serve as a center of excellence.

With these steps, Western armies can add an indispensable tool to their panoply of techniques to surprise, deceive, and survive.

Rémy Hémez is an officer in the French Army and former research fellow, the French Institute of International Relations (IFRI) (2015 to 2017). The views expressed are his own.

Image: Petar Milošević