The word ‘radar’ stands for Radio detecting and ranging. It makes use of very short radio waves called microwaves to find out how far away an object is and in case of a moving object in what direction it is moving and at what speed. These waves are transmitted from a special type of antenna which can direct a narrow beam of the radio-waves at a distant object. The antenna not only sends out the radio beam but also receives back the reflected signals from the distant object. The reflected beam is processed to produce an image on a screen similar to a TV screen, indicating the location of the distant object. Usually the antenna is made to rotate or oscillate horizontally to scan the horizon. By observing the position of the image produced over a period of time on the screen, which is marked with a scale of distances, the direction and speed of the object can be determined.
