If there’s a drone in the sky at this year’s Boston Marathon, these guys will know about it.

For the second year in a row, Virginia-based “DroneShield” will be setting up a series of drone detectors along the race route. The devices will be able to pick up the whirring sounds of the aerial objects and immediately notify Boston police and other law enforcement officials via text message or e-mail about their presence above the crowds.

“It’s an acoustic sensing of drone sounds,” said the company’s chief executive, James Walker. “We pick it up, and then we notify somebody — in this case the police department — in real time that a drone is in the area.”


And then they can go and find it, have a look at it, and see if it’s a risk or just someone playing with a drone in the wrong place at the wrong time, Walker said.

Drones are banned from being flown above and around runners and spectators, according to police.

Security is expected remain tight for the 120th running of the Marathon, which takes place Monday, but officials have said there is no specific threat to public safety.

Walker said the system — a series of square gadgets the size of a shoebox — works by acoustically identifying drones as they come into a specific area. “Sophisticated microphones” on the boxes, which can filter drown out background noise, working in concert with DroneShield’s technology, allow users to decipher what type of drone is being flown.

“We have a library of commercially available drones” in a database, said Walker. “A very sophisticated algorithm actually removes the background noise, and then compares the drones down to our library to identify what type of drone it is.”

Then the alerts are sent to authorities.


The company is volunteering its resources to police.

Last year, the company also showed up at the race with a small arsenal of drone net guns, which could fire nets to snare drones using CO2 cartridges similar to a BB gun. Neither the police nor the company used the nets, however. The company will not have them on hand this year, Walker said.

Steve Annear can be reached at steve.annear@globe.com. Follow him on Twitter @steveannear.