Aliasing-Free Velocity Measurement of FMCW Lidar System Enabled by Frequency Shifted Optical Beam

A new approach to avoid signal aliasing of a frequency-modulated continuous-wave (FMCW) Lidar is proposed. By virtue of a frequency shifted probe light enabled by an acousto-optic modulator (AOM) in a FMCW lidar system, the distance and velocity of a target can be measured unambiguously. Up to 34 m/s velocity of a target at close distance of 2.6 m can be well distinguished. The direction of the rotated target is also recognized.