The Doppler Wind Lidar principle

Doppler Wind Lidar principle: The lidar emits a laser pulse towards the atmosphere, then collects, samples, and retrieves the frequency of the backscattered signal. The received signal frequency is Doppler-shifted from the emitted laser due to the spacecraft, Earth, and wind velocity. The lidar measures the wind projection along the laser line-of-sight, using a slant angle versus nadir.