 Radar is an object detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar system consists of a transmitter producing electromagnetic waves. In the radio or microwaves domain, a transmitting antenna, the receiving antenna often the same antenna is used for transmitting and receiving and the receiver and processor to determine properties of the object s. Radio waves pulsed or continuous from the transmitter reflect off the object and returned to the receiver, giving information about the object's location and speed. Radar was developed secretly for military use by several nations in the period before and during World War II. A key development was the cavity magnetron in the UK, which allowed the creation of relatively small systems with submeter resolution. The term radar was coined in 1940 by the United States Navy as an acronym for radio detection and ranging the radio direction and ranging. The term radar has since entered English and other languages as a common noun, losing all capitalization. The modern uses of radar are highly diverse, including their interest real traffic control, radar astronomy, air defense systems, antimicile systems, marine radars to locate landmarks and other ships, aircraft anti-collision systems, ocean surveillance systems, outer space surveillance and rendezvous systems, meteorological precipitation monitoring, altimetry and flight control systems, guided missile, target locating systems, ground penetrating radar for geological observations, and range controlled radar for public health surveillance. High-tech radar systems are associated with digital signal processing, machine learning and are capable of extracting useful information from very high noise levels. Other systems similar to radar make use of other parts of the electromagnetic spectrum. One example is LiDAR which uses predominantly infrared light from lasers rather than radio waves.