an 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 (sonar is SOund NAvigation Ranging; asdic is Anti-Submarine Detection Investigation Committee)
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; sonar is an acronym for sound navigation ranging; asdic is an acronym for anti-submarine detection investigat
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
