Single-source dual-frequency laser coherent detection for high-speed moving targets

The maximum measurement speed of the single- frequency laser coherent detection system is limited. Hence, a single-source dual-frequency laser coherent detection method for high-speed moving targets is proposed in this paper. Two different frequency probes are generated by using the frequency shift method, and the dual-frequency signal light is combined with the dual-frequency local oscillator to obtain a multiorder component containing the target information. The relationship between the frequency difference, the detector bandwidth, and the maximum detectable speed of the system is given. The spectrum extraction method of the mixing components at different speed intervals is discussed. The feasibility of this method to improve the maximum detectable speed of the system is verified through simulation analysis. This work provides a theoretical basis for the design of laser coherent detection systems for high-speed moving targets.