General Science

  • noun a method of finding objects under water by sending out sound waves and detecting returning sound waves reflected by the object


  • A system utilized for the detection and location of underwater surfaces, objects and structures, via the reception of sonic or ultrasonic waves reflected by them. active sonar equipment transmits and receives sonic or ultrasonic sounds, for detection of the bearing and range of objects, while passive sonar equipment can only receive sonic or ultrasonic sounds, and is thus able to detect bearing only. A radar operates utilizing similar principles, but usually employs microwaves.
  • An apparatus utilized to generate, transmit, receive, and present information utilizing sonar (1). A typical set has a source of acoustic or ultrasonic power, usually an underwater sound projector, hydrophones to detect the reflected sonic or ultrasonic waves, a receiver, one or more speakers, and a display, such as a CRT or LCD. Also called sonar unit, sonar device, sonar equipment, sonar system, or sonar set.
  • synonymsound navigation and ranging


  • noun a system for detecting underwater objects through the transmission of sound waves, which are reflected back by the object