Unmanned aerial vehicles (UAVs) display an ever-expanding range of capabilities that can speed the pace of industry and help safeguard government installations.  But as their value increases, so, too, does the likelihood of unlawful surveillance and threats to the privacy and public safety from would-be spies and terrorists.  As a result, more companies are beginning to introduce drones whose primary mission is to intercept and divert these drone intruders before they can strike and wreak their havoc.

Broadly speaking, there are three main ways to intercept drones that pose a threat:  1) signal jamming; 2) propeller restriction (for example, by means of a net); and 3) aerial takedown. Signal jamming, like the service offered by the Battelle Defender, is not necessarily conducted with airborne drones.  In fact, it’s often conducted with a ground-based detection system.  It’s also far from fool-proof. Rather than down or divert an intruding drone, signal jamming may cause the craft to fly off course or even, as a fail-safe, continue to its intended target.  Typically, jamming is useful in short-range scenarios, when the invader is already threatening and an attack may well be imminent.

The second option, capturing or disabling drones by disabling their propellers, is often carried out by firing a net as a projectile from a ground-based launcher after an electronic countermeasures system has locked onto the drone and identified its precise flight path.  Airspace Systems, a San Leandro, CA-based technology firm, first introduced this capability in 2017, and it’s been successfully deployed ever since.  Other vendors include OpenWorks Engineering, which offers both a shoulder-mounted and turret-mounted net “cannon.”  Net interdiction captures the intruding drone mid-air and whisks it away before it can cause any harm.  But debris from the disabled drone can fall on buildings and people below.  Reloading the net also takes considerable time, so this system is mainly useful against a single intruder.  And even more than jammers, most net-based systems are only effective at extremely close range.

The third and most advanced and perhaps most effective anti-drone system would be conducted with a counter-drone specifically configured for this purpose.  These are largely experimental but there are solid prototypes with sensors and machine intelligence to autonomously intercept threatening drones at high speeds.  It is also possible to equip a UAV with a net capture system like the one previously described.  Other aerial drone hunters are being configured with the on-board technology to sense, detect and track an intruding drone and to disable its GPS system.  Here again, there is a danger that the intruder, if suddenly disabled, could crash and cause damage to people and property below.

Experiments are still underway to allow an aerial drone hunter to take over the intruder’s navigational system to guide it to the ground safely.  This is a very complex challenge and measures developed may only work against relatively unsophisticated drones without effective onboard ECM technology of their own.

As these examples illustrate, there is a growing need for a counter-drone capability to protect property and people from harm.  But the current methods, though viable, may not be 100% effective in all scenarios.  And they still come with risks.

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