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速度识别能力的高低直接决定了激光探测系统性能的优劣,受探测器带宽限制,传统激光探测系统无法实现对数马赫目标的速度多普勒信号检测。提出的同偏振双频激光相干探测测速方案成功解决了该难题,极大提高了系统效能。基于双频激光相干探测原理,分析了在实际应用中的振幅扰动、相位扰动及频率扰动等时频扰动对该系统信噪比的影响并与单频系统进行了对比。结果表明:单、双频系统回波信号信噪比受振幅扰动的影响基本一致;而针对各种频率扰动和相位扰动,双频激光探测系统回波信号信噪比明显高于单频激光探测系统,如当相位扰动达0.5π时,单频激光探测系统信噪比接近0dB,而双频激光探测系统信噪比仍高于18dB。
The speed recognition ability directly determines the performance of the laser detection system. Due to the limited bandwidth of the detector, the conventional laser detection system can not detect the speed Doppler signal of the logarithmic Mach target. The proposed dual-frequency laser coherent detection with polarization speed measurement program successfully solved the problem, which greatly improved the system performance. Based on the principle of dual-frequency laser coherent detection, the influence of time-frequency disturbance such as amplitude disturbance, phase disturbance and frequency disturbance on the signal-noise ratio of the system is analyzed and compared with the single-frequency system. The results show that the signal-to-noise ratio of echo signals in single-and dual-band systems is basically the same as that of amplitude-disturbances. However, the SNR of echo signals of dual-frequency laser detection system is obviously higher than that of single-frequency laser for various frequency disturbances and phase disturbances For example, when the phase perturbation reaches 0.5π, the single-frequency laser detection system has a signal-to-noise ratio close to 0dB, while the dual-frequency laser detection system still has a signal-to-noise ratio higher than 18dB.