Doppler Effect → Velocity
Reflected waves from a moving object experience a change in received frequency (Doppler Effect).
As the object comes closer, the frequency increases; as it moves away, the frequency decreases.
This frequency shift (Doppler shift) can be used to calculate the velocity.
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1. Doppler Effect in Continuous Wave (CW)
A continuous sinusoidal signal with a fixed frequency is transmitted toward a target.
When the target is moving, the reflected signal exhibits a frequency shift proportional to its radial velocity.
This frequency difference is used to determine the target’s speed.
2. Doppler Effect in FMCW
In FMCW radar, a time delay due to target range creates a frequency difference between the transmitted and received signals.
In addition, when the target moves with a certain velocity, an extra Doppler-induced frequency shift is added,
so the observed frequency difference contains both range and velocity components.
The extraction of the range-induced and Doppler-induced frequency components is described in the Range FFT and Doppler FFT sections of ANL.
Radar Sensor SoC & Module
WiFi IoT Module
5G/LTE/CAT-M1/NB-IoT
WiSUN/HaLow/Thread Module
