DRONES are wreaking havoc. Last year, London’s Gatwick Airport had to divert flights when a drone was spotted flying nearby. In the UK, there were more than 100 incidents involving drones close to airports in 2017 – the most ever, and other countries have seen similar increases. Reports of near misses are at an all-time high.
So authorities are eager to find ways to bring down drones safely and reliably. But the task is harder than you might think.
“Most options to either catch a drone in the sky or drive it out of the area are experimental or cause too much collateral damage,” says Mark Wiebes, Innovations Manager at the Dutch National Police. “Geo-fencing” is one option but even that is not foolproof and relies on users and manufacturers playing along (see “Bird in the hand“).
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That’s why Dutch police and the country’s Ministry of Justice and Security sponsored a competition designed to test out the tech required to take out a rogue drone.
Dubbed the “anti-drone” competition, the aim of DroneClash was to home in on a reliable way to pluck illegal or unwanted drones out of the sky. The organisers put up a $30,000 prize for the best idea.
“Tactics include spaghetti, string to foul propellers, firing darts at other drones and even an airgun”
In DroneClash, the teams each had to defend a “queen drone” and use “attack drones” to battle their opponents. To reach the queens, the attackers had to travel through the Hallway of Doom Death and Destruction, which included a variety of counter-drone measures such as bright lights, smoke and a net launcher. “DroneClash is like Robot Wars in the air,” says Bart Remes at the Delft University of Technology in the Netherlands, one of the competition’s organisers.
Teams could score points for taking down other drones, but maximum points were awarded for stopping drones, grabbing them and safely placing them in a nearby box. There were several knock-out rounds before the winner-takes-it-all finale.
Speaking before the event, William “IN-YOUR-FACE!” Thielicke, from team DiPol, described a cunning plan to use raw spaghetti, which he hoped would give his team the edge. As a defence mechanism, their queen was to have pieces of pasta, reinforced with cord around the strands and pointing in every direction, so that any drone flying near it risked a broken propeller.
Spaghetti attack
Dipol’s attack drones would also have a couple of pieces of spaghetti attached like a lance. “We will then crash into the other drones as quickly as possible,” says Thielicke – hopefully, taking out the competition in the process.
Other tactics included dangling a piece of string above a drone to tangle up the propellers so it falls out of the sky, firing darts at the opposition, and even an airgun to throw the target off-balance.
“In a practice session, there was a draft in the room that made the drone fly like crazy, we just couldn’t control it, so we’re trying to reproduce that,” says Daniel Vernis from a team called The Wand, who have developed a form of airgun.
But ultimately, the winners were the Laced Horns team who relied on pilot skill and bashing their opponents. “We had an amazing day,” says Geert Folkertsma, one of the team. “Our strategy was to go hard and fast: go directly for the queen and slam into it.” Their team members came from the University of Twente in the Netherlands and Clear Flight Solutions, a firm known for building flying robotic birds.
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Laced Horns made very robust attack drones with a frame extending all the way round the propellers, reinforced with carbon plates. To destroy the competition, they simply crashed into them. But they were lucky too, says Folkertsma.
There was a team that could hack into the radio communications, effectively taking over the control of opposition drones. But because Laced Horns used bespoke transmitters the hackers hadn’t had time to hack their systems. “A lucky escape!” says Folkertsma.
The event took place in a Dutch aircraft hangar near Leiden, and although it was designed to be fun, DroneClash has a more serious side. Drones have also been used to deliver contraband to people in prisons, as well as in an attempt to bomb a Russian airbase in Syria. “I know of one incidence where an ambulance helicopter couldn’t land because of a drone flying,” says Wiebes. “These are really serious incidents.”
A UK Department of Transport study last year showed that even a small drone may damage a helicopter’s rotors or a plane’s windshield. “We are a firm believer in drones and how they will improve society,” says Remes. “But there also need to be no go zones where we can take measures against drones for public safety.”
Bird in the hand
Anti-drone measures aren’t new, but few are very successful. Eagles trained by the Dutch police to pluck drones out of the sky and bring them back to base with their big talons looked promising for a while.
Unfortunately, eagles don’t like being told what to do. The project was scrapped over concerns that the birds might go after food instead of the intended target. The US Air Force is trying to find out if falcons are up to the task.
Another approach is to use a radio jammer in a particular area, so-called geo-fencing, so that the instructions from the pilot won’t be received. This could be effective in some instances, but may not work on drones that can fly autonomously.
The US military has previously released footage of a microwave gun that essentially fries a drone’s electronics. Though the approach could work on the battlefield, a drone falling in a civilian area could create a lot of trouble. Employing a laser gun creates similar problems.
What’s needed is some new ideas, and a big drone battle could be the way to generate inspiration (see main story).
