See:

• Animal echolocation: animals emitting sound waves and listening to the echo in order to locate objects or navigate.
• Human echolocation: the use by blind people of sound to navigate.
• Sonar: (sound navigation and ranging) the use of sound to navigate or to locate other watercraft, usually by submarines.
• Echo sounding: listening to the echo of sound pulses to measure the distance to the bottom of the sea, a special case of Sonar.
• Medical ultrasonography: the use of ultrasound echos to look inside the body

See also: Animal echolocation is the ability of some animals to locate objects by emitting sound waves and listening for the echo. ... A schematic representation of hearing. ... Human echolocation is a technique used by some blind people to navigate within their environment. ... Blindness can be defined physiologically as the condition of lacking visual perception. ... The F70 type frigates (here, La Motte-Picquet) are fitted with VDS (Variable Depth Sonar) type DUBV43 or DUBV43C tugged sonars Sonar (sound navigation and ranging) is a technique that uses sound propagation under water to navigate or to detect other watercraft. ... There are several traditions of navigation. ... USS Los Angeles A submarine is a specialized watercraft that can operate underwater. ... Echo sounding is the use of sound pulses directed from the surface or from a submarine vertically down to measure the distance to the bottom by means of sound waves. ... Medical ultrasonography is an ultrasound-based diagnostic imaging technique used to visualize internal organs, their size, structure and their pathological lesions. ... Ultrasound is sound with a frequency greater than the upper limit of human hearing, approximately 20 kilohertz. ...

• Radar: locating objects by detecting the echo of emitted radio waves