Drones are everywhere. We’ve seen from Ukraine news how effective even slower, older drones can be in a military campaign. Paparazzi use drones to invade the private lives of celebrities. Law enforcement uses them for surveillance and tracking. Drones aid land surveyors for plotting areas. And folks love taking recreational airborne tours and testing their piloting skills. The U.S. FAA estimates that the recreational drone fleet was 1.5 million in 2020.
But the potential for drones to compromise airspace and critical infrastructure, whether deliberately or unintentionally, is a serious matter.
A sampling of events: at London’s Heathrow airport, a drone flying at 3,200 feet came within 10 feet of a Virgin Atlantic plane on its descent. A drone crashed on the White House south lawn. There was an attempted attack on a Pennsylvania electrical substation; the drone had a trailing copper wire tether which if in contact with high-tension equipment, could have caused fire and/or damage. There was the drone attack of the Aramco Abqaiq oil processing facility in Saudi Arabia which caused fires that resulted in serious disruption of oil production and, of global financial markets. Via drone, Greenpeace dropped a smoke signal devise on roof of the Orano nuclear storage building in La Hague, to demonstrate its vulnerability. Criminals use drones to transport contraband. And at LAX International Airport between 2019 and 2020 drone incursions increased threefold. Also at LAX last year, a drone fitted to look like a manned jet pack (known locally as “Jetpack Man”) has been sighted repeatedly at dangerous altitudes.
Whether a distraction to pilots or a vehicle for an intentional attack, the proliferation, advancing technology and affordability of drones means threats will only mount.
What are the options for defending against this threat?
As tempting as it might be to just shoot an annoying drone out of the air, that is of course illegal, plus the drone could well catch on fire and the flying debris is a risk to things and people on the ground. Drones are considered aircraft by the National Transportation Safety Board and are protected, just like a Boeing 747 or Piper PA-28, by federal law.
Step one obviously is to know what’s in the sky. The FAA and National Aeronautics and Space Administration are developing a joint traffic control system for low flying drones: “Unmanned Aircraft System Traffic Management (UTM) is a ‘traffic management’ ecosystem for uncontrolled operations that is separate from, but complementary to, the FAA's Air Traffic Management (ATM) system. UTM development will ultimately identify services, roles and responsibilities, information architecture, data exchange protocols, software functions, infrastructure, and performance requirements for enabling the management of low-altitude uncontrolled drone operations.”
A new FAA rule went into effect requiring remote drone identification. Operators transmit identification, location and performance info so that air traffic folks on the ground and other airspace users can see the data. This helps law enforcement and security officials figure out which operators are in compliance and which are not, the assumption being that the latter are more likely to pose security risks.
Small UAS Drone pilots require certification that involves getting a tracking number and passing a test and are required to request LAANC approval for landing in controlled airspace below 400 feet. That’s all fine but aren’t the bad guys the least likely to follow rules? A malicious attack can happen so quickly. While important for safety reasons to identify and track everything in an airspace, mapping won’t necessarily thwart threats by inept pilots or by bad guys.
Mitigation efforts can leverage current tracking technologies that include acoustic and optical sensors, lasers, radar and lidar (radar ornithology technology in place for detecting birds is well adapted to finding drones and even categorizing them for type), radio frequency scanners, thermal and video cameras.
Counter-UAS systems work by detecting-tracking-identifying these tiny aircraft, defeating them and communicating in a way that allows uninterrupted operations with the other systems in place. For example, anti-drone radio wave technology detects the signal transmission between a drone and its remote control. Although detection range is typically limited, using an array of RF sensors ups the coverage area. The technology is not perfect. One challenge is frequency-hopping spread spectrum which hop between channels faster than RF sensors can sweep. So, there is RF technology that can then incapacitate the drone once its detected by telling the drone it has to go home or land, the party’s over.
The tricky bit is how to use some of these technologies in civilian versus military contexts. Who is allowed to disrupt a drone and under what circumstances has to be perfectly clear and non-offensive drones (to say nothing of airport operations) must remain safe.
Note: The Faith Group authored a comprehensive research report “Guidance for Integrating Unmanned Aircraft Systems (UAS) into Airport Security” (2019) in collaboration with Program for Applied Research in Airport Security, managed by Safe Skies and funded by the FAA.