A doppler radar is a radar using the doppler effect of the returned echoes from targets to measure their radial velocity. To be more specific the microwave signal sent by the radar antenna's directional beam is reflected toward the radar and compared in frequency, up or down from the original signal, allowing for the direct and highly accurate measurement of target velocity component in the direction of the beam. Doppler radars are used in air defense, air traffic control, sounding satellites, police speed guns, etc.
Recent weather radars process velocities of precipitations by Pulse-Doppler radar technique, on top of their intensities. This is a slightly different treatment of Doppler data that has been publicized so much in the United States that the term Doppler radar is wrongly confused by the public in that country with weather radar.
