Doppler radar is a radar that uses the Doppler effect for positioning, speed measurement, and distance measurement. The so-called Doppler effect is that when a vibration source such as sound, light, and radio waves moves relative to an observer at a relative speed V, the vibration frequency received by the observer is different from the frequency emitted by the vibration source. Because this phenomenon was first discovered by Austrian scientist Doppler, it is called the Doppler effect. The frequency change caused by the Doppler effect is called the Doppler frequency shift, which is proportional to the relative speed V and inversely proportional to the frequency of the vibration.

formula

Frequency shift (F_r) = F_t × ( (1+(v/c)) / (1-(v/c)) )

Doppler frequency (F_d) = F_r - F_t

F_t = original frequency, c = speed of light