The proliferation of these flying objects worries the authorities. Army, industrialists and start-ups are looking for solutions.
False assault on the Bugey nuclear power plant by Greenpeace (July 3, 2018) over Fort Brégançon (July 6), where Emmanuel Macron was spending his holidays, going through the attack of Venezuelan President Nicolas Maduro during speech (August 4), or the disruption of air traffic due to intrusions into airports, the use of drones for malicious purposes is spreading. A new danger from the sky? "The threat is protean and has various levels of seriousness – from privacy to terrorist risk," says Henry de Plinval, director of the drones program at the National Office for Aeronautical Studies and Research (Onera).
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To protect themselves, public authorities and big business are struggling. "The security of the airspace can be schematized in three acts", explains Henry de Plinval. Detection, ie 24-hour surveillance of a given site and the triggering of an alert in the event of an intrusion; identification, to confirm and qualify the threat – is it a simple shooting, espionage, or even a terrorist action? – then to locate the device or the pilot; finally the neutralization, which is concretized by the capture, the jamming or the destruction of the aircraft.
Merge means for near-perfect detection
"There is no panacea in this area, warns the manager.Each situation requires appropriate responses depending on the location (city, countryside, nuclear power plant, airport, prison …), financial means, technical context and available human forces ". For the detection phase, an active radar is generally used – it emits an electromagnetic wave, the sound of which makes it possible to locate any object moving in a given radius.
One can resort to a passive radar, which tracks all the surrounding waves in search of a microchange. Similarly, acoustic tracking systems can be deployed, but they are inefficient in a noisy environment like cities. Finally, laser radars (Lidar) or the technique of direction-finding, which focuses on the exchanges between the operator and his aircraft, also help to detect flying machines.
On a site to protect, once the threat is confirmed, the identification will be performed by a human operator or an automatic turret that will use high resolution cameras and / or infrared. "Artificial intelligence algorithms for pattern recognition can be very useful, for example, by distinguishing a bird from a drone, so as not to trigger the alarm for nothing," says Onera's expert. The ideal is obviously to adapt and combine all these technologies. "Today, by merging radar data and radio direction-finding surveys, we have almost no false alarms," confirms Michel Dechanet, the "Mr. Drones" of Thales Air Systems.
The European electronics group, specialized in defense systems, is committed to the Hologarde project (in partnership with Aéroports de Paris) to develop ultra-powerful radars. "They detect objects of about 10 centimeters at a maximum distance of 5 kilometers, says the engineer.By next year, we hope to extend our field to 10 kilometers. A project "closely monitored" by the army, says the Air Corps General Jean-Christophe Zimmermann, adding that the French forces have already chosen, as part of the program "Intermediate means of fight against the drone", a semi-automatic system. automated combining radar and optronics.
The last and most complicated step is to neutralize the intruder. However, to date, jamming is by far the most effective way. "There are different systems, but all operate on the same principle: saturate the frequencies, as if you were shouting at a human to deconcentrate", illustrates Henry Plinval. The GPS signal used by the drones to move can be parasitized with one or more frequencies to disorient the machine.
The "decoy" GPS is a variant to deceive the target device by sending him a real GPS signal indicating a false position. Finally, if the drone is manually controlled by a camera, it is also possible to disturb the video signal until the operator can see nothing. But there is a problem with all these scrambling solutions. "Their employment in war zones seems ideal, but on the national territory, it remains very framed because of the many negative impacts, because it can disrupt other equipment," said Michel Dechanet. Consequently, their use is strictly forbidden, except by the military in case of threat to the security of the country. "The bigger the surface to protect – imagine an airport or an urban environment – the more difficult the system to deploy," says Thales.
Rifle jammer or hacking?
Hence the idea of developing targeted jamming means. Like that of the Lille company MC2 Technologies, which designed the Nerod F5, a kind of "rifle" of 6 kilos. By pointing his cannon – a large antenna that theoretically covers all frequencies – he can cut the link between the drone and the station with which it communicates on the ground. Result: the aircraft is found as "paralyzed", it starts its autopilot and lands, or flies hovering until the batteries run out, before falling. The project, developed partly with funding from the General Delegation of Armament (DGA), remains very secret: the specificities of the weapon as its operational radius remain jealously guarded.
What about hacking? "It's time to break that myth," said Lucas Le Bell, CEO of CerbAir, "This solution can be effective with small, unsecured gears or toy drones that use Wi-Fi, but it quickly becomes limited with devices. a bit sophisticated. " His start-up works on a system that detects communications between the pilot and his machine within a radius of 2 to 5 kilometers thanks to a passive listening technology. Thus localized, both can be "neutralized at the source" by the security forces or police. In the same vein, there are other more radical methods. Like the trap, which boils down to shooting with a gun on an unidentified drone to neutralize it. In addition to an imperfect success rate, such a practice poses some dangers to people, especially in urban areas.
Raptors, fragile, are overwhelmed by technology
Some companies have also developed alternatives, such as net guns. "This is the last resort, once the aircraft has entered the protected area, draws Richard Gill, CEO of the British start-up Drone Defense, his weapon, the Net Gun X1, which can capture a craft until 15 meters away, has already proven itself in prisons in the United Kingdom, others are working on hunter drones, equipped with a jamming system or a net, or even on flashlights to neutralize flying cameras, or "kamikaze drones" that hit enemy targets, not to mention the animal solution: the Dutch police were the first in 2016 to set up eagles to intercept drones. fire: not only is their maintenance expensive – the poor raptors are sometimes injured because of the propellers – but especially the speed and maneuverability of the new models of drones have put them out of play.
For its part, the French army continues to "train a handful of birds in the military base of Mont-de-Marsan," says Etienne Patry, Chief of Staff of the Air Force Command. But the recent attack of a girl – confused with a drone – by a Royal Eagle of the army, could sound the death knell of the ornithological weapon. "The final decision will be stopped at the end of the year," promises the general. Before anticipating: "The use of raptors by the army, even though they may be useful in specific cases classified as 'secret-defense', remains less easy than that of dogs. not be significant enough to be retained ". Still, even without these zealous predators, drones are now subject to sharp surveillance.
ZOOM: airports, regulations harden
To fly a drone less than 5 kilometers from an airport is illegal in most countries of the world – in France, this limit is even set at 10 kilometers. But the operators, malicious or misinformed, do not always respect these prohibitions. The Dubai airport, one of the most active in the world, has suspended its activity several times due to overflight, resulting in cascading delays and millions of euros in losses. The European Aviation Safety Agency (EASA) has identified 1,400 drone incidents in Europe in 2016. This number pushed MEPs to adopt stricter rules and harsher penalties in June 2018.