Evaluations of commercial technologies to detect, track and identify (DTI) small drones operating in restricted airspace in and around airports are “generally” performing well, but the Transportation Security Administration (TSA) is finding that electronic noises created by radar and communications used for airport operations do impact the performance of the drone detection systems, an agency official said on Tuesday.

“When you go to an airport, we see degradation of the performance,” said Austin Gould, acting executive assistant administrator for Operations Support. “There’s so much ambient energy in the airport environment from the radars, communications and whatnot, that the detection capability of the systems is somewhat compromised.”

The ongoing drone DTI evaluations at Miami International and Los Angeles International Airports will help TSA understand the limitations of the technology, he said.

TSA won’t be certifying the counter-unmanned aircraft systems (C-UAS), but it does plan to tell operators how well they work in an airport environment and if they work as advertised, Gould said at the American Association of Airport Executives annual Aviation Security Summit.

Gould said an incident at Reagan National Airport this summer near Washington, D.C., where a drone was flying about 500 feet above ground-level in the flight path of aircraft and forced a brief stop in operations “opened a lot of eyes across government that something needs to be done.” The testing at Miami began in Aug. 2021 and at LAX in August 2022.

Gould warned that the evaluations at the two testbeds will sunset if Congress doesn’t reauthorize legislation giving the Department of Homeland Security C-UAS authorities. The reauthorization could expire this Friday if Congress doesn’t extend a resolution keeping the federal government funded in fiscal year 2023.

Incidents of small UAS interfering with airport operations aren’t new. Gatwick Airport near London had to shut down hundreds of flights over two separate days in December 2018 due to drone sightings.

Gould said visual sightings of small drones around airports aren’t reliable. At Miami in 2021, there were about 200 reports of drone activity, but when DTI technology was employed there were more than 20,000 detections, he said. The siting at National Airport was visual.

“Technical reporting or technical detection is the only way to go, especially at night when a lot of these things happen,” Gould said.

Despite the limitations of the C-UAS systems, Gould said they “generally work well” but it “depends on the system.” Most commercially available small drones are produced by China’s DJI and the C-UAS technologies that TSA has been evaluating at the airport testbeds are “really good at detecting DJI drones…because they have a very predictable signal,” he said.

Drones that aren’t built by DJI is where “we have a hard time doing detection” because the C-UAS systems “aren’t necessarily tuned for that,” Gould said. “They’re small, they’re fast moving, they can mimic birds, for example.” He said the detection challenge for the non-DJI drones extends to the ground control stations as well due to a less “predictable signal being transmitted.”

Still, some DTI technologies are “virtually ready for use in the airport environment” and “others need a little bit more maturation,” Gould said. Right now, it comes down to having the equipment tuned into the signal of the known drone, he said.

He also said that drone detection with radar is also “challenging” because the UAS are small.