PARIS — Police in Paris are busy walking through the worst-case scenarios. One is a drone appearing out of nowhere, undetected because it flies low and emits no radio waves thanks to its autonomous navigation. The reason? They’ve been tasked with protecting two major events being organized in France: the Rugby World Cup in September and October 2023, and then the Olympic Games in July and August 2024.
The war in Ukraine has also upped the stakes. Numerous videos show how both Ukrainian and Russian forces have turned simple commercially purchased drones into weapons. And a recent French Senate report, “Drones in the Armed Forces,” reveals that the number of civilian drones in France has grown from 400,000 in 2017 to more than 2.5 million today, including 40,000 devices weighing over 800 grams.
Detecting radio frequencies
As a result, authorities fear how terrorists could use recreational drones (less than 25 kg). “Imagine a drone spreading baby powder during a soccer game. This will cause a panic with potentially deadly consequences,” says Mary-Lou Smulders, marketing manager at Dedrone, a U.S.-based company that provides anti-drone warfare (ADW) solutions to civilian authorities as well as the military.
ADW technologies usually have two lives: they are often first developed to protect the military before being used for large-scale festive events. The United States, with its huge military R&D budget, and Israel, which has long been confronted with rocket attacks, are at the forefront. But the European Union is trying to catch up. The European Defense Agency (EDA) coordinate the military research efforts of its 27 states.
We are encouraging cooperation between the civilian and military sectors.
“We are encouraging cooperation on the sharing of requirements between the civilian and military sectors, on interception technologies, but also on communication protocols between these systems,” insists Dion Polman, who oversees air superiority programs at EDA.
ADW can be broken down into three phases: detection, classification, and neutralization. “Detection can be done by radar, by direction finding to detect the radio frequencies used by the drone, and by all-weather infrared and optical cameras,” says Thierry Bon, director of anti-drone solutions at Thales, which is an electronics company that was awarded the 2024 Olympic Parade security contract.
Classification is key
The next step in detection is to identify drones that follow a predefined route autonomously, thanks to their camera. No radar signal, no radio wave, no GPS signal! The solution could come from an unlikely place: acoustics.
“Around the site to be protected, microphones pick up sounds; artificial intelligence analyzes this data 40 times a second to locate the acoustic signature of a drone, identify the model in question and assess its direction,” explains Sébastien Hengy, a researcher in acoustics. The location information is transmitted to a high-precision camera whose images allow an operator to assess the dangerousness of the aircraft.
This is the second phase of ADW: classification. Databases of reported flights can spot drones that stray from their course. High-definition cameras can zoom in and see if the drone is carrying a suspicious payload (but terrorists may have disguised a grenade as a fake camera…).
Artificial intelligence algorithms predict the drone’s trajectory and advise the operator on the most opportune moment to intervene, minimizing the risk of collateral damage caused by the fall of the aircraft. This is the third step: neutralization.
A laser defense
Wave jammers are still effective against most recreational drones. “We can also jam the GPS, which will force the aircraft to land,” says Paul Philippart, marketing manager of MC2 Technologies, a company that markets anti-drone systems and which is involved in the Olympic Parade program with its jamming systems. But some leisure drones can now function without the airwaves.
The future lies in lasers, already developed by the United States and Israel. In France, an order for a laser turret for the 2024 Olympic Games has been already been placed with a company called Cilas: “During tests conducted last year, we destroyed mini-drones – devices weighing less than 15 kg – at a distance of one kilometer, with a laser shot lasting 5 to 7 seconds,” describes Benoist Roucher, a sales manager at the company.
The advantages of the laser are that it is inexpensive, invisible to the naked eye and therefore difficult to attribute, and, above all, it is scalable. “Depending on the power of the laser used, we can either dazzle or blur the camera of the drone or destroy the device completely,” says Roucher.
