云层厚度对蓝绿激光通信性能的影响分析

Analysis of the effect of cloud thickness on the performance of blue-green laser communication

针对机载激光发射器位于云层上方或云层中央时,云层的存在会降低激光通信性能的问题,仿真分析了不同类型的云层对激光能量衰减、信噪比、最大码元传输速率与误码率的影响。得到结论:云的存在主要造成激光能量衰减,影响最大传输速率与误码率,但对信噪比影响较小。链路余量大于18.9 dB的通信系统,链路上允许存在4 km的云层。云层对最大通信速率与误码率的影响主要是时间扩展造成码间串扰。卷云对通信性能几乎无影响;积云对通信性能的影响较大;层云、层积云和积雨云对通信性能的影响更大,但三种云的差异很小,可不作区分;高层云和雨层云对通信性能影响最大,其中雨层云的影响比高层云更大。

When the airborne laser transmitter is located above or in the center of the cloud,the cloud will reduce the laser communication performance.In order to solve this problem,the effects of different types of clouds on laser energy attenuation,signal-to-noise ratio(SNR),maximum symbol transmission rate and bit error rate are simulated and analyzed.It is concluded that the cloud mainly causes laser energy attenuation,which affects maximum transmission rate and bit error rate,but has little effect on SNR.For communication systems with link margin greater than 18.9 dB,4 km cloud cover is allowed on the link.The effect of cloud on the maximum communication rate and bit error rate is mainly caused by inter-symbol crosstalk caused by time extension.Cirrus has little effect on communication performance,cumulus has a great impact on communication performance,and stratus,stratocumulus,and cumulonimbus have a greater influence on the communication performance,but the differences between the three types of clouds are small and could be not be distinguished.Altostratus cloud and nimbostratus have greatest influence on communication performance,of which nimbostratus has greater influence than altostratus cloud.