光在大气和海水信道中传输的能量衰减计算

考虑自然光和海水浮游生物等产生的背景辐射以及云层、大气/海水界面和海水等介质的光辐射透过率,利用星载激光对潜通信能量方程估算了潜艇接收信号能量衰减大约可达-112~-140 dB.利用Monte Carlo方法计算星载激光对潜通信水下接收光斑分布状况,选择63%光斑半径作为接收平面半径,不考虑光在传输过程中介质的吸收效应,计算了不同卫星高度和发射角.近海岸海域水下200 m和深海海域水下300 m接收信号衰减,信号能量衰减可达84 dB.由于未考虑吸收效应和光斑大小选择的原因,仿真计算结果稍小于理论估算.

Calculation of energy attenuation of light propagation through atmosphere and seawater

With the energy equation,the received signal energy attenuation of spaceborne laser submarine communication is estimated; its attenuation is about -112 dB to -140 dB.The estimation considered the background emission caused by sky light and plankton in seawater,the optical radiation ratio communication medium which include of cloud,the interface between atmosphere and seawater,and sea.Based on Monte Carlo method,the distribution of underwater light spot is calculated,which is applied to the spaceborne laser submarine communication.The 63 percent radius is defined as a effective radius,which coved with the 63 % of the total photons that can arrived at receiving flat.Unconsidered the absorption effect of medium,the receiving signal attenuation of underwater 200 m near coast or underwater 300 m in the deep sea area is calculated with the different satellite attitudes and laser scattering angles.The energy attenuation is up to 84 dB.The simulating result is lower than the theoretical estimation,because of the absorption effect is not considered and the different selected light spot radii.