Drones can navigate like bats using four mics and a speaker
 

Bats can find their way in the dark using echolocation, so why can't drones? Researchers have managed just that. They've developed a system that lets a drone navigate using just four microphones and a speaker. It relies on the familiar concept of mea...

https://www.engadget.com/2020/03/04/...ate-like-bats/