How do you bring down a drone?

The best way to bring down a drone – not with a skeet-shooting mentality, says Oleg Vornik, CEO of Sydney-based DroneShield. That’s fine for the sporting field, but it’s a whole different world when it comes to protecting politicians, stadiums, and combat patrols.

“It’s the most natural question people ask,” Vornik says. “The answer is it’s very difficult to do. You have a small object, perhaps as big as a dinner plate, blending in against a complex background or a similar colour to the sky. And it’s moving erratically.”

The builder of drone tracking and disabling technology says he’s seen trained military personnel fire dozens of shots trying to bring down a drone just 30 metres away.

“Those bullets are going to land somewhere. So you’re going to have collateral damage”.

Mostly drones are helpful tools or enjoyable pastimes, but they can also be unwanted spies in the sky, delivery devices for acts of terrorism, or – as in Ukraine – front-line combatants.

Countering them, says Vornik, is a complex equation of risk against reward, and cost versus return.

“If you’re a military base, chances are you want to take down the drone as fast as possible,” says Vornik. But using a $150,000 shoulder-launched Stinger anti-aircraft missile against a $1500 off-the-shelf drone isn’t economically viable.

“If you’re a prison, for example, we don’t recommend you take it down,” he adds. “That’s a temporary solution. But if you track in real time where it lands, who picks up its package and who’s controlling it, you can solve the whole crime in one hit”.

Battle of attrition

Sci-fi-inspired ideas of flashing lasers, darting interceptor drones and radar-guided slugs are often the first thoughts that come to mind to defeat swarms of cheap, nimble opponents. But there are practical, real-world issues to consider, says Vornik.

“With lasers, it’s like a naughty child trying to burn ants with a magnifying glass,” he says. “The ant is running for its life, and the kid has to try and hold it in the focal point long enough to have an effect. And what if there are five ants? It’s actually very, very difficult”.

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Miss in a stadium, and you may take out the eye of a sports fan. Miss on the battlefield, and you may blind a friendly satellite far beyond your target.

And any laser-based weapon system needs large power generators, complex lenses, and a high-resolution targeting system to put – and keep – the narrow beam on target.

“I think lasers definitely have a place,” he says. “But most lasers today are the size of a car. They’re very expensive. They may be effective against missiles, but swarms of small drones are another matter altogether”.

The proliferation of such commercially-available devices is forcing militaries and governments to rethink their policies.

“Drones are so ubiquitous,” he says. “They can be everywhere. But if you’ve only got five exquisitely effective systems to respond with, then your response is crippled from the start.”

Freeze, then drop

Unlike lasers, radiofrequency jamming devices can be small, portable, and energy efficient.

They “fire” beams of radio waves over a distance measured in “multiples” of kilometres (the actual ranges remain an operational secret). Each beam, like that of a searchlight, can catch more than one drone in its “glare”. The drones lose contact with their controllers.

“The jamming effect is instantaneous,” Vornik says.

Drones flying on autopilot must access satellite GPS navigation signals or electronic beacons. “These can be disabled using our jammers”.

And holding the beam on them longer magnifies the effect.

“It will freeze a drone,” Vornik adds. “It will put it on the ground”.

Such DroneShield systems neutralised four suspicious devices amid the tens of thousands of people attending the inauguration ceremony of Brazilian President, Luiz Inácio Lula da Silva, in January this year.

Sense and sensibility

Vornik says his business started in 2015, using acoustic sensors to detect and isolate the sound of drones.

“The problems were numerous,” he says. “The most obvious is that it’s very imprecise. And it can be saturated in a noisy environment like an airfield or stadium”.

Radar, at first glance, appeared to be an obvious alternative.

But when it comes to areas with lots of moving objects – such as forests, fields and football fields – it’s almost impossible to discriminate between a flitting bird, a meandering cow, a frantic fan and a low-flying drone.

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“So we came up with the hand-held radio frequency sensor,” Vornik says. “It’s basically identifying the uplinks and downlink signals between the drone and the controller. The flight telemetry. The video feeds.”

Such transmissions can be triangulated at distances of multiple kilometres. And their details are assembled via software, overlaid on digital maps, and displayed on portable devices.

“Radiofrequency is a complex sensor to develop but fairly cost-effective to build,” says Vornik.

Develop, react, adapt

“To counter cheap, disposable drones, you need to have not-quite disposable but very cheap drone countermeasures. Systems you can make and use on a similar scale,” says Vornik.

Drones must then be shielded to defeat RF jamming. That could involve anything from expensive gold foil, casings of thick aluminium plates, or satellite-grade radiation-hardened computer chips. Navigation and communications equipment must also be more powerful, complex, and resilient. This, in turn, means more powerful engines and batteries are needed to carry all the extra weight.

Such an arms race puts cheap, off-the-shelf drones at the bottom of the heap.

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DroneShield’s portable RF solutions are easy to handle. They have few moving parts and carry the same standardised rechargeable high-capacity batteries used in other military devices, such as night vision goggles, radios and portable computers.

“We build them to use as little energy as possible,” says Vornik. “We don’t even do little coloured screens because they consume more energy and drain batteries faster”.

Each RF jammer carries enough power for a day’s worth of use and spare batteries can be easily carried.

And the portable drone detectors are passive, meaning they emit no signals. Radars, for example, rely on bouncing radio waves off objects to “see” them. But those same radio waves reveal the transmitter’s location.

“With radiofrequency, you’re invisible until you choose to light up your jammer,” Vornik explains. “And then you will want to move pretty quickly to avoid a responsive artillery strike if you’re fighting a near-peer adversary like in Ukraine.”