Radar "is the transliteration of the English word" Radar ", derived from the abbreviation of" radio detection and ranging ", meaning" radio detection and ranging ", which is the use of radio methods to discover targets and determine their spatial positions. Therefore, radar is also known as "radio positioning". Radar is an electronic device that uses electromagnetic waves to detect targets. Radar emits electromagnetic waves to illuminate targets and receives their echoes, thereby obtaining information such as the distance, distance change rate (radial velocity), azimuth, and altitude from the target to the electromagnetic wave emission point.