空间激光通信探测器阵列接收合并技术

Receiving combination technology with detector array for spatial optical communication

大气湍流、吸收和散射等因素引起的光强闪烁严重影响了空间激光通信系统的效率,导致激光束能量衰减、信噪比下降,探测器阵列分集接收技术能有效克服这种影响。主要研究了探测阵列分集接收的三种合并方式,即选择式合并、等增益合并和最大比合并。分析对比了三种合并方式在提高功率增益和信噪比方面异同点。在相同大气湍流和中断概率条件下,最大比值合并对信号改善最为明显,等增益合并次之,选择式合并在分集接收中对信号改善最小。当两路分集接收时,最大比合并相对于无分集时信噪比改善因子提高了100%,等增益合并提高了78.5%,选择式合并提高了50%。最大比合并实现复杂,选择式合并实现相对容易,可根据实际工程性能要求,选择合适的合并方式。

The light scintillating caused by atmospheric turbulence,absorption and scattering has a serious impact on the efficiency of the space laser communication system.They can cause the energy attenuation of the laser beam and the decrease of the signal-to-noise ratio（SNR）.Detector array diversity reception technology can overcome this effect effectively.Three combining modes of diversity reception with detector array are studied,they are Selection Combining,Equal Gain Combining and Maximal Ratio Combining respectively.The performances of three combining modes are compared at power gain improving and signal to noise ratio.Under the condition of the same atmospheric turbulence and outage probability,Maximal Ratio Combining is the most obvious at improving signals,followed by Equal Gain Combining,and the minimum signal improvement is the Selection Combining.For two detectors diversity reception,SNR improvement factor increases 100% for Maximal Ratio Combining,78.5% for Equal Gain Combining and 50% for Selection Combining compared with the traditional method.Maximal Ratio Combining is complex to achieve and Selection Combining is relatively easy to implement.So the suitable combining method could be selected according to the actual project performance requirements.