采用双频激光相干探测技术实现高速目标的多普勒测量。结合随机统计理论和维纳-欣钦定理推导得到存在强度扰动时双频激光相干探测的信号功率谱函数,基于理论模型分析了拍频线宽和扰动频率对信号功率谱的影响,并进行了数值仿真和实验研究。结果表明,功率谱分布表现为洛伦兹型,在远距离探测时,拍频信号线宽的增加使功率谱展宽。强度扰动频率接近多普勒频移量时,功率谱展宽,幅度下降,这增加了频谱提取难度,降低了多普勒测量精度。

Dual-frequency laser coherent detection technology is used to perform the Doppler measurement of high-speed targets. The power spectral function of the electric signal for the dual-frequency laser coherent detection with intensity disturbance can be obtained by combining the random statistical theory with Wiener-Khintchine theorem. Based on the theoretical model, the influences of beat line width and disturbance frequency on the signal power spectrum is analyzed, and the numerical simulation and experiments are conducted. The results reveal a Lorentz-type power spectrum distribution. For long-distance detection, an increase in the line width of the beat signal broadens the power spectrum. When the intensity disturbance frequency is close to the Doppler frequency shift, the power spectrum broadens and the signal amplitude decreases. In this case, the spectrum extraction process becomes more difficult, and the Doppler measurement accuracy decreases.