Single-source double heterodyne coherent detection high-speed moving target

A novel single-source double-heterodyne coherent detection high-speed moving target is presented. Under a limited detector bandwidth condition, the method inherits the characteristics of dual frequency laser coherent detection and transforms the Doppler shift of a high-speed moving target to low frequency using the beat frequency difference method. Compared with the traditional heterodyne detection system, the maximum speed detectable range of the system is greatly increased. The double-heterodyne mixing process is deduced, and the relationship between the beat frequency, detector bandwidth, and maximum detectable speed of the system is obtained through analysis. Thus, the beat frequency can be dynamically adjusted for the system to adapt to different measurement environments. Different signal components and speed information extraction methods of detectors under different motion speeds are analyzed. The feasibility of the method is verified through simulation. Moreover, the data acquisition is minimal, and the system has good real-time performance.