双波段近海激光通信大气参数测量与估算模型修正

Measurement and Estimation Model Correction of Atmosphere Parameter for Offshore Laser Communication by Dual-Bands

针对定量评估大气湍流对近海激光通信影响的问题,提出了基于对850 nm和1550 nm波段激光光斑同步采集的大气折射率结构常数测量方案。采用现场可编程门阵列(FPGA)+多核数字信号处理器(DSP)架构的实时图像处理系统实现目标中心位置的提取与目标灰度和的统计,进而得到激光自发射端至接收端的到达角起伏方差和闪烁指数。将两个不同波段的同步采集结果分别代入已有的大气折射率结构常数计算模型中,比较同一模型不同波段所得结果的相似性,并对相应模型中的参数进行修正,使同一时刻及环境的两种波段条件下,经修正模型计算得到的大气折射率结构常数相对稳定可靠。实验结果表明,采用改进模型对大气折射率结构常数进行计算,所得结果相似度不低于80%,可作为定量评估大气湍流对近海激光通信影响的重要参数。

For quantitative evaluation problems of the influence of the atmospheric turbulence on offshore laser communication, an approach of measurement of the atmospheric refraction structure constant is proposed based on acquisition and synchronization of 850 nm and 1550 nm band of the laser. Using real-time image processing system field programmable gate array （FPGA） and multi-core digital signal processor （DSP） architecture to realize extraction of target center position and statistics of target gray, the angle of arrival fluctuation variance and the scintillation index are obtained. The dual-band results are calculated by the classic model to obtain the atmospheric structure constant of refractive index and then the obtained results of dual-band under the same condition are compared, and the parameters of the corresponding model are revised, so that the atmospheric refractive index structure constant is calculated to be relatively stable and reliable. Experimental results show that using the improved model to calculate the atmospheric refractive index structure constant, the similarity of results is not less than 80%, and the important parameters can be used as a quantitative assessment of the influence of the atmospheric turbulence on offshore laser communication.