机载激光通信光学窗口气动光学效应分析  

Analysis of aerodynamic optical effects in airborne laser communication optical windows

作　　者：姜逸渊 孟立新[1,2] 张立中[1,2] 刘智[2] 董科研[2] Jiang Yiyuan;Meng Lixin;Zhang Lizhong;Liu Zhi;Dong Keyan(School of Mechanical and Electrical Engineering,Changchun University of Science and Technology,Changchun 130022,China;Space-to-Ground Laser Communication Technology Key Laboratory,Changchun University of Science and Technology,Changchun 130022,China)

机构地区：[1]长春理工大学机电工程学院,吉林长春130022 [2]长春理工大学空地激光通信技术重点学科实验室,吉林长春130022

出　　处：《红外与激光工程》2024年第4期254-265,共12页Infrared and Laser Engineering

基　　金：叶企孙科学基金项目(U2141231)。

摘　　要：机载激光通信中通信光束散角小、系统跟踪精度高,光学窗口的气动光学效应会引起远场光斑形状和位置发生变化,降低通信性能。为此,通过Fluent对共形和平面两种光学窗口整流罩在不同飞行高度、速度、方位角下的外流场进行稳态仿真分析,利用相位屏分析远场自由衍射光斑变化。结果表明,共形窗口在俯仰、高度和速度变化中的流场更加稳定,呈现更为一致的变化趋势,且在远场衍射中表现更好。平面窗口在方位转角变化大与低速的飞行工况下,RMS值低于共形窗口。远场光斑发生偏移和弥散的程度与波面畸变成正相关,但在波面畸变较大的情况下,RMS值不能完全定义其对光学系统的影响。同时,当俯仰角靠近机体表面、降低飞行高度、增加飞行速度均会增强波面畸变。Objective Wireless laser communication technology has advantages such as high communication speed,good security,and portability,making it widely applicable in both military and civilian communication fields.Aircraft,as one of the crucial platforms for wireless laser communication research,can effectively enhance the reliability and applicability of laser communication,playing a significant role in the future integrated aerospace network.However,the practical application of airborne laser communication faces various challenges.Apart from common atmospheric laser communication issues like atmospheric absorption,scattering,platform vibrations,and cloud cover,aerodynamic optical effects pose a significant constraint on the application of airborne laser communication.Methods This paper addresses the issue of selecting the shape of the optical window for the airborne laser communication optical terminal.It designs streamlined fairings with conformal and planar optical window shapes(Fig.3).Fluent is used to simulate and analyze the flow field around the fairings under different flight altitudes,speeds,and azimuth angles.The refractive index distribution at the front end of the optical window is obtained based on the density and refractive index relationship(Fig.7).Then,using the ray tracing method,the wavefront distortion of the two windows under different conditions is obtained(Fig.6),verifying the independence of the optical grid and tracing length in ray tracing(Fig.8-9).Finally,the far-field free diffraction spot changes are analyzed using phase screen analysis(Fig.13).Results and Discussions The results show that,at different azimuth angles,RMS increases first and then decreases,reaching a minimum at 90°,and rapidly increasing after exceeding 90°,reaching the maximum at 180°(Fig.10).Overall,the RMS caused by the spherical window is slightly larger than that caused by the planar window.When changing the pitch angle,the spherical window exhibits good flow field consistency,while the planar window has some influenc

关 键 词：机载激光通信 气动光学 远场衍射 光学窗口 

分 类 号：TN929.12[电子电信—通信与信息系统]