Aug 21, 2017 06:07 PM

New Blocking Devices Put Rogue Drones in Jam

Are pesky drone daredevils who like to buzz airports, stadiums and other sensitive spots about to be grounded?

Innovators of a new generation of drone-jamming products in China hope so.

The industry that aims to control rogue drones is in its infancy. So far, the early products come in two types: those that cut off the signal that allows the operator to drive the drone, and others that allow authorities to take control of the unmanned aerial vehicle. In theory, stopping rogue drones sounds simple. In practice, it is still quite challenging and costly — and could even lead to mishaps.

But the need for such products has become clear to authorities in China, a leading drone innovator and the source of 70% of all drones sold worldwide.

China’s Civil Aviation Administration said on July 18 that there have been at least 44 cases of rogue drones wandering into airport airspace this year — six times more than in the same period last year. Meanwhile, 790 flights have been affected by drones so far this year, compared to last year’s 101.

In one of the biggest drone-related safety scares to date, more than 100 flights at Chengdu Shuangliu International Airport were delayed or rerouted in April after eight drones entered the airport’s flight control area.

An amateur drone user in January even livestreamed footage of a Beijing Capital Airlines plane passing close to his drone.

Drones could cripple a jetliner. The impact of a drone on a jetliner has been likened to that of a cannonball strike.

drone police

A police officer uses an anti-drone device to control an unregistered drone during a dragon boat race in Nantong, Jiangsu province, on May 30. Local police have been using such technology to manage illegal drone flights during major public events. Photo: Visual China

Drone jammers

Currently, there are no systematic, large-scale, anti-drone measures to protect airports, prisons, nuclear power plants and other sensitive areas.

Authorities overseeing airports and other high-security sites are scrambling to defend these places against rogue drones. In addition to demarcating no-fly zones and mandating real-name drone registration, they are embracing new technology.

At the second Shenzhen International Unmanned Aerial Vehicle Expo in June, drone-makers and anti-drone device manufacturers shared an exhibition space.

The anti-drone technology on display fell into two main categories: “oppressive” devices, designed to cut off the signal between drones and remote controls; and “deceptive” devices, which can hijack a drone by changing its “home” GPS coordinates.

Both types of technology work by transmitting radio signals to jam drone communications. Portable, oppressive drone-jamming devices, shaped like rifles, are a common example — one was used before a Chinese Super League match in Wuhan in March, when two drones were spotted hovering meters (yards) above the stadium crowd. After a police officer aimed a gun-shaped device at the drones and pulled the trigger, the drones slowly descended.

These portable devices, which have a range of 2 kilometers (1.2 miles), are currently being used at large-scale sporting events, parties, and conferences. Like most conventional guns, they depend on the person using them to spot and aim at a target.

But airports cover a far larger area than the average stadium, and needing to depend on security staff to detect trespassing drones might mean they are spotted too late.

“The main problem is personnel — the airport will require dozens or even hundreds of staff to patrol it,” Xu Xu, chief technology officer at anti-drone tech company, told Caixin.

“If the target is outside the jamming gun’s range, you have to send a car over. A car, a person, and a gun, that is basically the current solution,” Xu said. “And once the drone is within range, only luck will help you spot it immediately.”

Xu thinks airports could benefit from positioning jamming equipment along the edges of runways to “protect the runway like a fence.”

An official at Guangzhou Baiyun Airport told Caixin that the airport has designed a three-part anti-drone system that could take the guesswork out of drone detection.

The system includes an early warning system that combines radio, infrared, and visible-light detection technology, the official said. A back-end system responsible for taking action and striking or driving away rogue drones links up to the early warning system through a central management platform. But Guangzhou Baiyun’s three-part system is still in development.

Limitations still a problem

Even as tech entrepreneurs and airport managers scratch their heads over how to handle trespassing drones, some industry insiders are worried that anti-drone equipment could pose a whole other set of risks.

In an online essay, Civil Aviation University of China Vice Principal Wu Renbiao pointed out that since civil aircraft are vulnerable to radio interference, using interference to tackle drones could also threaten civil aviation systems. The development of an anti-drone market means making interference methods available to more people, some of whom could turn against the planes that manufacturers are trying to protect, Wu added.

One anti-drone equipment supplier told Caixin that jamming guns are used only sporadically around airport perimeters — drones communicate primarily at the frequencies of 2.4 gigahertz (GHz) and 5.8 GHz, which are also commonly used by Wi-Fi-enabled devices, airport ground control, and mobile internet devices. Poorly aimed drone jammers could disrupt vital communications systems.

Additionally, drones flying in cruise mode are harder to disrupt than remote-controlled drones. Airports can use radio hijacking technology to seize control of a rogue drone and guide it toward a safe landing spot.


But so many different drone systems exist, even within one manufacturer’s product range, that the cost of developing a comprehensive hijacking system is extremely high, Fang Wanchun, a manager at Shenzhen-based Southern Software told Caixin.

Another, simpler problem is also proving difficult to solve — once drones are intercepted, “you need to make sure they won’t simply fall and crash into passers-by,” an industry insider told Caixin.

Huang Xin, chief technology officer at Shenzhen Zhouxin Technology, said: “When a drone loses its signal, some manufacturers’ factory settings will instruct it to land, or automatically reverse course. DJI drones, for example, will do this. But if manufacturers do not program such a setting, the drone will move unpredictably.”

Da-Jiang Innovations Science and Technology Co., Ltd. (DJI) is a leading producer of consumer drones, accounting for over half of the global market. Anti-drone product developers often use DJI products as simulation targets.

“Drones made by major manufacturers have a landing mechanism that will execute when the signal is cut off,” Xu said. “But some smaller-brand or DIY (do-it-yourself) drones don’t have this setting.”

A Shenzhen public security bureau official told Caixin: “With this kind of drone, in order to ensure safety, we have to intercept it physically.”

A number of anti-drone product makers have boasted that DJI drones can definitely be “defeated.” But the results of anti-drone measures are harder to predict when drones from smaller brands are involved. Some anti-drone businesses can guarantee the effectiveness of their wares only with particular drone models.

“No technique is 100% perfect.” Civil Aviation Administration air traffic control office director Xu Hao told Caixin, adding that protecting airports from drone interference is a “worldwide problem.”

Contact reporter Teng Jing Xuan (

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