为研究双频激光雷达技术在高超声速目标探测方面的应用, 理论分析了激光在等离子中的吸收衰减特性, 以RAM-C实验数据为参考, 通过仿真计算得到不同高超声速飞行场景下钝头体模型的等离子体电子密度, 验证了计算的准确性。计算得到钝头体驻点线上温度分布范围为8 000~16 000 K, 并结合理论分析得到了激光在等离子体鞘套中的衰减与电子密度、温度和激光频率的关系, 表明等离子体鞘套对激光的吸收十分微小; 通过对双频激光和单频激光在湍流传输中回波信噪比的对比分析, 得到了双频激光的抗湍流干扰特性。由此表明双频激光雷达是探测高超声速目标的有效方式。

In order to study the application of dual-frequency lidar in the detection of hypersonic target, the absorption and attenuation characteristics of laser in plasma were analyzed theoretically. Based on the measured data of RAM-C experiment, the plasma electron density of blunt body model in different hypersonic flight scenarios was obtained by simulation calculation, which verified the accuracy of the calculation. The temperature distribution on the stationary line of blunt body was calculated from 8 000 K to 16 000 K, and combined with theoretical analysis we can obtain laser attenuation in plasma sheath on electron density, temperature and laser frequency, which showed that the absorption of laser by plasma sheath was very small. By comparing the echo signal to noise ratio of dual-frequency laser and single frequency laser in turbulent transmission, the anti-turbulence characteristics of dual frequency laser were obtained. Thus shows that the dual-frequency lidar is an effective way to detect the hypersonic target.