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n. A system using transmitted and reflected underwater sound waves to detect and locate submerged objects or measure the distance to the floor of a body of water.

n. An apparatus, as one in a submarine, using sonar.

n. Echolocation.

n. echolocation

n. A device that uses hydrophones (in the same manner as radar) to locate objects underwater.

n. a measuring instrument that sends out an acoustic pulse in water and measures distances in terms of the time for the echo of the pulse to return

"It was detected about five years ago with sonar from a surface vessel."

navigational instrument    measuring device    measuring instrument    measuring system   

Doppler sonar   

radar    infrared    comm    subspace    navigational    long-range    scanner    ultrasonic    seismic    sensor