Sound navigation and ranging system (5)

I believe the answer is:

sonar

(Other definitions for sonar that I've seen before include "Underwater navigation device" , "Underwater detector" , "Undersea sensing system" , "Echo-sounding equipment" , "Echo-sounding device" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.