Thereceiver measures the waves which are bounced back by the object.
By doing this, the radar can locate the object. Radar is used in many different ways. It can measure the speed and number of cars on a road, the amount of water in the air, and many other things.
The radar transmitter sends radio pulses. By controlling how often the rapid pulses of radar energy are sent out by a radar transmitter (called the transmitter's "pulse repetition rate"), and how long it takes for the reflected pulse energy to come back to the radar receiver, one can tell where objects are, and how far away.Digital circuits in a radar receiver calculate the distance to an object by knowing the time interval between energy pulses. The radar receiver's digital circuits count how long it takes between pulses for an object's reflected energy to be detected by the radar receiver. Since radar pulses are sent and received at approximately thespeed of light, the distance to an object can easily be calculated. This is done in digital circuits by multiplying the speed of light by the time it takes to receive the radar energy reflected back from an object.
The time between pulses influences how far away an object can be detected. That distance is called the "range" of a radar transmitter and receiver. Radar transmitters and receivers use slow repetition frequencies to find the distance to objects that are far away. This makes it possible to accurately determine the distance to the moon, for example. Fast repetition is used to detect objects that are much closer, like ships at sea, high flying aircraft, or to determine the speed of fast moving automobiles on highways.
Radar was first used in 1904 byChristian Hülsmeyer. He was given a patent for radar (Reichspatent Nr. 165546). Radar was vital in theBattle of Britain and other parts ofWorld War II. TheAxis countries failed to keep up with British and American radar technology during the war.
The wordRADAR was created in 1942 as anacronym forRadioDetectionandRanging.[1] This acronym replaced the BritishinitialismRDF (Radio Direction Finding). The word is now thought of by many people as a regular word, no longer as an acronym.
