收发分置氦激光雷达系统参数设计与性能分析

Parameter Design and Performance Analysis of Bistatic Helium Lidar System

针对收发分置氦激光雷达系统,基于连续激光束成像技术,获得了不同收发分置距离下对应的距离分辨率大小,以及单列CCD像素元与高度的对应关系和距离分辨率随高度的变化曲线.对比分析了在不同亚稳态氦原子密度的条件下,系统单列像素元接收到的光子数与探测高度的对应关系,并获得了信噪比和相对误差随探测高度的变化情况.仿真结果表明,增加积分时间可以提高信噪比,在400~1 000 km的高度范围内,积分时间为2 h,距离分辨率为50 km时,信噪比在10~65范围内,相对误差小于10%.研究结果表明采用收发分置氦共振荧光激光雷达系统可实现对热层200~1 000 km亚稳态氦密度的探测,为进一步完善优化收发分置氦共振荧光激光雷达系统的方案提供参考.

According to the atmospheric continuous laser beam imaging technology,the corresponding resolution range for the distance between separated transmitter and receiver on bistatic helium lidar system is obtained,as well as the relationship between the single-row CCD pixels and the altitude,and the variation curve of resolution range with different altitudes.Moreover,the corresponding relation between the number of photons received by the system′s single-row pixels and the altitude under different metastable helium densities is analyzed,and the signal to noise ratio and relative error varied with altitude are obtained.The simulation results indicate that the signal to noise ratio can be improved by increasing the integration time.In the range of altitude from 400 km to 1 000 km,when the integration time is 2 h and the range resolution is 50 km,the signal to noise ratio is in the range from 10 to 65 and the relative error is less than 10%.These results prove that adopting the bistatic helium resonance fluorescence lidar system can detect the metastable helium density of the 200~1 000 km thermosphere,which provides a reference for further perfecting and optimizing the scheme of the bistatic helium resonance fluorescence lidar system.