To protect this year's Boston Marathon runners and spectators from drone-borne threats, a Washington, D.C.-based company patrolled the event with drone-detecting sensors and net guns.
Boston Police Commissioner William Evans noted that the anti-drone technology was going to be part of the equipment used to make last Monday's race safe, though no specific drone-borne threats were detected. At the 2013 Boston Marathon, pressure cooker bombs set off just shy of the finish line killed three people and injured 260 others. Earlier this month, one of the two brothers who made and placed the bombs was convicted of 30 charges connected with the attack. (The other suspect in the bombing died during a car chase and gunfight with the police.)
DroneShield's system to counter unmanned aerial vehicles consisted mainly of audio detectors, designed to pick up on the specific sounds made by the small remotely piloted craft, with programs to filter out false positives. For this year's marathon, DroneShield placed 10 sensors along the marathon route.
In addition to the special sensors, the Boston Globe reports that Brian Hearing, a DroneShield co-founder, brought net guns up to Boston so that police could have a drone-specific weapon to use, should any hostile drones be detected. Nets are great, because they gum up drone rotors but don't really pose a major risk to anyone else (unlike, say, shotguns or machine guns).
Without any inappropriate drone use to report, it’s hard to say how well DroneShield worked at protecting the marathon. But anytime an event is so safe that we can’t tell whether a security system worked, that's a net win.