Two U.S. Navy scientists have invented a passive, onboard collision avoidance system for small drones by attaching miniature microphones to the tips of propellers.
In an official U.S. patent application, the Naval Information Warfare Center-Pacific explains why engineer Paul Swanson and mathematician Stephen Hobbs devised the device, which can be used for UAV navigation, UAV collision avoidance, and counter-UAV systems.
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