Write a short note on Sonar

Sonar (sound navigation and ranging) it is a device that uses ultrasonic waves to measure distance,direction and speed of underwater objects. The transmitter produces and transmit ultrasonic waves.These waves travel through water and after striking the objects on seabed,get reflected back and are sensed by the detector.The detector converts ultrasonic waves into electrical signals which are interpreted. The time taken for the echo to return to ship is measured by sonar apparatus.The distance of underwater object is then calculated from time taken by echo to return.The time it takes for an echo to return is used to find out how far away something is. 2d=v*t d=distance from ship to the bed of the sea v=speed of sound through seawater t=time interval between transmission and reception of ultrasound signal.