Optical frequency shifted FMCW Lidar system for unambiguous measurement of distance and velocity

•A novel and simple FMCW Lidar system is proposed to measure distance and velocity unambiguously by using an optical frequency shifted probe light.•Real-time measurement of a target operated at up to 26.43 m/s at a close distance of 1.267 m is demonstrated.•The rotated direction of target can be discriminated via a single fast fourier transform analysis.•A free space circulator is applied to provide a clean RF spectrum for beat signal measurement.•Three-dimensional mapping for distance and velocity of the target are reconstructed.