Single frequency continuous wave radar can measure the speed of the target, but it can't measure the distance. Multi-frequency continuous wave radar can measure the distance and distinguish between fixed targets and moving targets. FM CW radar can measure the distance and speed of the target, but it is only suitable for a single target. Because it is difficult to isolate the transmitting and receiving systems of CW radar, its application is limited. Continuous wave radar is mainly used for Doppler navigation, speed measurement, altitude measurement, proximity fuze, missile guidance, target search, tracking and identification, target indication, battlefield surveillance, stealth aircraft shape research and so on. Foreign countries have been equipped with continuous wave radar since 1960s. By the 1980s, this kind of radar basically used solid-state circuits and microprocessors, with various working modes, anti-jamming, self-checking and anti-nuclear radiation capabilities. For example, the AN/APN-23 1 CW Doppler navigation radar of the United States was successfully developed and put into use in 1984. It is equipped on EA-6A electronic track aircraft and combined with flight instruments such as flight attitude control system, air data computer, search radar and electronic warfare system to form an integrated avionics system. 1984 The continuous wave Doppler navigation radar series successfully developed in Britain, through the application of microprocessor technology to the tracking controller, has greatly improved its functions, and at the same time improved its ability to suppress radio interference and resist electronic reconnaissance. The ground continuous wave radar in the United States is in the leading position in the world. HIREE radar, RTVS gun tracking radar and 386 ground surveillance radar used for stealth aircraft shape research are all advanced continuous wave radars in the 1980s.