【作者】 董冉；

【导师】 艾勇；

【作者基本信息】 武汉大学 ， 通信与信息系统， 2013， 博士

【摘要】 现代舰船通信设备包括了各种短、中、长波的射频通信,以及古老的灯光通信,已经发展成一个成熟的系统。但随着技术的进步,现有的射频通信手段开始显露其五项主要的不足之处：带宽有限、易暴露目标、加解密工作复杂、频道管理严格、容易受到电磁干扰。灯光通信也有着自动化程度低、需要专业信号兵、通信速率过低等缺点。舰载激光—灯光通信一体机正是解决以上问题的有效途径。舰载激光—灯光通信一体机将集无线激光通信和全自动灯光通信一体。即以无线激光通信技术为基础,根据舰载平台的特点进行针对性设计,实现舰载无线激光通信。再利用激光通信终端的APT (Acquisition,Pointing,Tracking)系统的硬件完成全自动灯光通信的功能,使其在能进行无线激光通信的基础上还能向下兼容常规的灯光通信。本文对舰载激光—灯光通信一体机的若干关键技术进行了研究。文中首先介绍了国际和国内机动平台包括舰载激光通信的成功案例,调研了舰载无线激光通信的研究现状,以作为设计参考。然后分析了舰载无线激光通信链路的特点。从激光在普通大气中传输所受影响开始,分析大气对激光造成的吸收和散射,接收端的光强起伏、到达角起伏,以及背景辐射的影响。然后介绍了近海面大气的特性,这包括其大气结构常数随高度、风速、温度、季节、地点的变化,近海面大气对大气的衰减效应随高度、时间的变化。最后介绍了舰载无线激光通信接收端端机会使用的多模光纤耦合效率的特性。激光—灯光通信一体机的APT系统是其关键技术。从介绍舰船晃动的特性开始,进行了简单情况下的晃动仿真,以细化舰载平台的特殊影响。研究了跟瞄误差和光功率的关系,对两种常见APT系统的结构进行了比较。然后分别从粗跟踪硬件、软件以及精跟踪、硬件软件四个部分对系统设计进行详细阐述。最后对粗、精跟踪信息的交互和跟瞄误差进行了分析。灯光通信是激光—灯光通信一体机的另一个重要功能。因此,对其硬件上和粗跟踪的共享和需求上的不同进行了研究,并讨论了软件部分的图像处理算法。按以上系统的设计,搭建立了激光—灯光通信一体机的APT系统和灯光通信功能的验证平台,分别对粗跟踪对快速目标的跟踪功能、精跟踪对平台振动的抑制功能、以及灯光通信的白天、夜间环境下的通信进行了实验。结果表明粗、精跟踪系统分别能对大范围的运动和小角度的抖动进行有效抑制,其中粗跟踪系统可对2.7°/秒角速度的目标进行有效跟踪,残差控制在0.017°以内,残差主要频率小于9Hz。而精跟踪系统对于0.0158。角度频率为25Hz的抖动可有效跟踪,因此可以认为精跟踪系统能够补偿粗跟踪系统残差。而灯光通信系统在3.5km的通信距离下实现了15字/分钟的通信,其夜间能够不受恒亮干扰源的影响。但白天受背景光影响较大,该距离下在可能在背景光非常强的晴天的中午无法通信。更多还原

【Abstract】 Modern warship communication equipment including a variety of short, medium and long wave radio frequency communication and even the old light communication,has grown into a mature system. But with the progress of technology, the existing radio frequency communication had shown five major disadvantages: limited bandwidth, easy to reveal, and the complex decryption, strict channel management, susceptible to electromagnetic interference. Light communication also has disadvantages of low degree of automation, needed of professional sailor, lower communication rate. Shipborne all-in-one for laser and light communication is the best way to solve the above problems.Shipborne all-in-one for laser and light communication will unite the free space laser communication and the automatic light communication together. It based on the free space laser communication technology and the existing light communication, and was specially designed according to the characteristics of the Shipborne platform. Using laser communication terminal APT (Acquisition, Pointing,Tracking) system hardware to realize automatic light communication function, can make it compatible with conventional lights communication on the basis of wireless laser communication. In this paper, some key techniques of ship-borne optical camera is studied.The succeful case of international and domestic mobile platforms laser communication including shipboard was introduced as a design reference.The characteristics of shipboard wireless laser communication link was analyed. The impact of atmosphere on laser transmitting, the atmospheric absorption and scattering of laser, the light intensity fluctuation and the arrival angle fluctuation at the receiving end, and the influence of background radiation were introduced. Then the characteristics of the atmosphere close to the sea-surface was studied.It includes the relationship between atmospheric refractive index and height, wind speed, temperature, the change of season, location was showed. And the Close to sea surface atmospheric attenuation effect to the laser about height and time in one day was analysed. Finally the coupling efficiency characteristics of the multi-mode fiber in the receiving end was introduced.The APT system is a key technology to the laser-light communication all-in-one. The analysis to characteristics of ship rocking, and a simulation in simple case was done to refine the influence of the carrier platform to laser communication. The relationship between tracking-pointing error and optical power was showed, the comparition of two common APT structure was done. And there is a detailed description for the whole system,respectively from coarse tracking hardware, software, and hardware and software of fine tracking system. Finally, coarse and fine tracking information interaction and tracking-pointing error are analyzed.Light communication is another important feature of the optical communication all-in-one. Therefore the the sharing hardware and the different demand of the coarse tracking the light communication was discussed, and the part of image processing algorithms in the software was elaborated. According to the above system design, optical communication all-in-one APT system is established.The experiment about the performance of coarse tracking for rapid tracing, precision tracking of platform vibration by the fine tracking system, light communication and lighting during the day, night were tested. Results show that the coarse and fine tracking system were effective, respectively for compensation a wide range movement and the small angle jitter.The coarse tracking system can be effective to2.7°/SEC angular velocity target tracking, with0.017°residual.The main frequency of the residual was less than9hz. The fine tracking system was effective for a0.0158°and25Hz frequency jitter tracking. So it can deemed that the fine tracking system can compensate the coarse tracking system residual error. The light communication systems achieved15words per minute communication rate at a distance of3.5km.In the night it will not affected by constant disturbance light source. but greatly influenced by the background during the day time. the distance in May in the background light at noon can’t communicate very strong sunshine. The system may no work correctly under such a distance in a strong background light in a sunshine noon.更多还原