Sonar (sound navigation and ranging) was originally a device for detecting and locating objects underwater by the reflection of sound waves. Today, it refers to all underwater hearing devices which are used for listening to sounds made by ships, marine animals or to any underwater sound. Sonar uses technique of sending out pulses of sound into water and detecting their echo from targets such as ships, submarines, fish etc. By calculating the time taken by the pulse to go out, get reflected and return, and by multiplying it by the known velocity of sound in water, the distance between the object and the sonar can be found out. Sonar can also be used on land is used for locating gas and oil.
|A Sonar Device|