【作者】 詹恩奇；

【导师】 王宏远；

【作者基本信息】 华中科技大学 ， 信息与通信工程， 2007， 博士

【摘要】 星载激光对潜通信(Spaceborne Laser Submarine Communication)由于其数据传输率相对现有通信方式较高，同时能够确保潜艇通信时的隐蔽性要求，因此，对其进行研究具有重要的军事应用意义和研究价值。SLSC研究内容极为广泛包括：大气和海水信道研究、星载激光器研制、潜艇接收天线研制、接收信号处理等等相当多的关键问题。本文主要分析光信号在地球大气和海水信道的传输问题，并对星载激光器的功率、发散角、轨道高度、脉冲重复频率等参数以及PPM(Pulse PositionModulation)帧结构设计提出参考建议。详细分析了地球大气分层结构、成分组成对大气光学散射、衰减特性的影响，讨论了海水的物理成分以及其固有和表观光学性质。详细阐述了模拟光子在大气和海水信道传输的Monte Carlo方法，对其在文章中应用的假定条件进行了说明。对光子传输过程中的相关内容确定进行了讨论，内容包括散射后位置确定、运动方向确定、光子自由路径长度、终止判决以及散射相位函数对比与确定。提出综合分析地球大气和海水信道对星对星载激光脉冲信号空间扩展效应的观点，分析计算了卫星运行在不同轨道高度、发射机发散角变化、海域条件不同时，不同水下深度的信号光斑分布状况。计算结果为星载激光器设计提供了设计依据。完成了光在地球大气和海水信道传输过程中由于散射作用产生的信号多径时间扩展模拟计算。计算并讨论了不同轨道高度、不同发散角大小、不同海域、不同水下深度光信号的时间扩展分布。根据计算结果为星载激光器发射频率及PPM帧格式提出了参考。参照激光通信能量方程，理论估算了激光对潜能量传输衰减。同时，利用MonteCarlo方法模拟对比计算了不同激光器轨道高度、不同发射机发散角大小、不同海水条件及不同水下深度条件下，大气和海水信道对光传输的衰减大小。根据地球大气和海水信道对星载激光脉冲信号的空间扩展分布和时间扩展分布的计算结果，考虑国内外激光器研制现状与星载装备条件限制，借鉴国外已成功进行了卫星间和星—地激光通信测试的激光通信卫星设计参数，提出了星载激光器一些工作参数选择参考，内容包括激光器输出功率、脉冲重复频率、发散角、卫星轨道高度、工作波长。考虑水下接收信号的时间扩展分布和PPM帧格式要求，提出了PPM帧格式并估算了相应的数据传输率。论文最后对大气和海水信道对光传输性能影响下一步的研究工作进行了展望。更多还原

【Abstract】 Spaceborne Laser Submarine Communication, has being an interestedcommunication technology, due to its data transfer rate higher than current communicationmethod, and be helpful for hiding submarine trace during communicating. The research ofSLSC is the important for military application. It includes, the research of atmosphere andseawater, spaceborne lidar manufacture, receiving antenna manufacture, and signalprocessing technology, etc.This dissertation analyses the laser pulse transmission through atmosphere andseawater, and gives some advice for designing spaceborne laser, such as the output power,the beam divergence angle, orbit altitude, pulse repeat rate, the configuration of PPM. Itsmain contributions are as follows.The optical scatterance and attenuation properties of physical constituents inatmosphere/sea optical channel are studied and summarized in the paper.The application of Monte Carlo method in simulating the transport of photons inatmosphere/sea optical channel, and its presumptions, are discussed in detail. Thesediscussed contents involve photon’s position after collision happened, moving direction,free distance for photon traveling through scatter medium, stopping judgment, comparisonand choice of scattering phase function.The calculations of spatial spreading effects when light traveling in atmosphere andsea scattering channel, are finished in the paper. The power distributions of laser signal onconditions of different orbit altitude, vary divergence angle of transmitter, sea areachanged, and different under-water target depths are studied in detail. The powerdistributions can be reference for confirming some working parameters of space laser.With the laser communication energy fuction, the propagation attenuation of the lasersunmarine communication is estimated in theory. At the same time, the Monte Carlomethod is introduced for calculating the propagation attenuation following with the lightpulse traveling in atmosphere and seawater channel. These calculation are finished withsome different conditions, including of different orbit altitude, vary divergence angle oftransmitter, sea area changed, and different under-water target depths. The both estimationresults are contrasted.The paper finishes the calculations of multipath temporal spreading effects followingwith photons traveling in the atmosphere and the seawater. The multipath temporal spreading distributions of laser signal on conditions of different orbit altitude, varydivergence angle of transmitter, sea area changed, and different under-water target depthsare discussed. These calculations can give some advices for obtaining the pulse repeat rateof laser and the PPM frame format.Based on these above-mentioned results about temporal spreading and spatialspreading, the limit of current national laser, abroad laser communication satellite whichsucceeded in satellite- satellite communication or satellite - earth platform communication,the dissertation proposes some laser transmitter parameters about output energy, pulserepeat rate, the beam divergence angle, orbit altitude, laser wavelength, and theconfiguration of PPM. At the same time, the data transmitting rate is calculated withcorresponding parameters of laser transmitter and PPM frame.In the end, the paper gives some assumptions about researching the transmitionperformance with the light traveling through atmosphere and seawater channel.更多还原