Radar is a radiolocation system that uses radio waves to determine the
distance ( ranging ), angle (azimuth), and radial velocity of objects
relative to the site. It is used to detect and track aircraft, ships,
spacecraft, guided missiles, and motor vehicles, and map weather formations,
and terrain. A radar system consists of a transmitter producing
electromagnetic waves in the radio or microwaves domain, a transmitting
antenna, a receiving antenna (often the same antenna is used for transmitting
and receiving) and a receiver and processor to determine properties of the
objects. Radio waves (pulsed or continuous) from the transmitter reflect off
the objects and return to the receiver, giving information about the objects'
locations and speeds.