基于可见光的水下通信技术研究

发布时间：2018-05-20 13:46

本文选题：水下 + 可见光通信　；参考：《中国海洋大学》2014年硕士论文

【摘要】：近年来，海底观测网络的建设，成为海洋地质调查、海洋内环境观测、矿物资源勘探的重要技术手段。而作为其技术支撑的水下声、光传感器和以自主式载人和非载人潜航器（AUV、ROV）为代表的水下潜航器械的快速发展，在给科研和工程带来极大便利的同时，也对所使用的水下通信方法的连续性、高效性、高速性和系统性有着更高的要求。当前主要的几种水下通信方式有：水声通信、超低频无线电通信和铺设海底光缆。但与水下可见光通信技术相比，还存在着通信距离短，通信速率低，设备庞大、昂贵、不利于集成，方向性、保密性差等方面的缺点。相比较而言，基于可见光的水下通信技术具有通信速率高、费用低、仪器体积小巧、易集成以及保密性好等优点。由于激光调制的调制速率高，单脉冲能量高，水下可见光通信可以达到更高的通信速率（几百兆到千兆的传输速率），更宽的通信带宽；大功率发光二极管和激光二极管的不断更新换代，光探测器的技术发展，一方面使得光源体积越来越小，并能更好地集成在各种科考系统中；另一方面，器件价格的低廉似使得系统的成本更低；激光的发散角小，方向性好，不但减小了光在传输过程中的能量损耗，也保证了通信的保密性；另外，可见光对电磁的抗干扰能力更强，不容易受海洋内环境变化的影响，在水下通信能实现更好的稳定性。因此，本文就基于可见光的水下通信的关键技术做了研究和分析，具体研究方法及成果如下：（a）针对水下可见光通信的关键技术分别做了对比分析：对通信的海水信道特性，分别从吸收、散射和其他因素给出分析模型；对光调制技术和光电探测技术结合原理和现存技术做了分析；对水下可见光通信的编码方式做了对比分析。（b）设计了基于532nm激光器和光电倍增管的光收发链路，具体根据所选器件设计了光接收电路、调理电路、耦合电路、电平转换电路、单片机控制电路，并编写了单片机软件和上位机软件，，搭建了完整的水下可见光收发平台。（c）针对当前集中常用的编码方式，利用单片机软件实现了各种编码方式的通信调制，包括开关量直接调制（OOK），曼彻斯特编码（ManchesterCoding）、4位和16位的脉位调制（PPM）。（d）设计了实验室调试和水下通信实验，对可见光在通信编码方面的表现特性和水介质中的传播特性有了更直观的认识，也通过一个量化的评估对实验对象进行评估测量。
[Abstract]:In recent years, the construction of seabed observation network has become an important technical means for marine geological survey, marine environmental observation and mineral resource exploration. The rapid development of underwater acoustical instruments, as their technical support, and the rapid development of underwater vehicles represented by autonomous manned and non manned subcarrier (AUV, ROV), is brought to scientific research and engineering. At the same time, it also has higher requirements for the continuity, efficiency, high speed and systematicness of the underwater communication methods used. The main types of underwater communication are underwater acoustic communication, ultra low frequency radio communication and laying submarine optical cable. Low speed, large and expensive equipment are not conducive to integration, directionality and poor security.
In comparison, underwater communication technology based on visible light has the advantages of high communication rate, low cost, compact size, easy integration and good secrecy. Because of high modulation rate and high single pulse energy, underwater visible light communication can achieve higher communication rate (several hundred megabytes to Gigabit transmission rates) and wider communication. The bandwidth of the letter, the continuous updating and replacement of the high-power LED and the laser diode, the development of the photodetector, on the one hand, make the light source smaller and smaller, and can be better integrated in various science systems. On the other hand, the low price of the device makes the system lower, the laser's divergence angle is small and the direction is good. However, the energy loss in the transmission process is reduced and the communication security is guaranteed. In addition, the visible light has a stronger anti-interference ability to the electromagnetic, and it is not easy to be affected by the changes in the ocean environment, and the underwater communication can achieve better stability.
Therefore, the key technologies of underwater communication based on visible light are studied and analyzed in this paper. The specific research methods and results are as follows:
(a) the key technologies for underwater visible light communication are compared and analyzed. The characteristics of communication sea water channel are analyzed from absorption, scattering and other factors respectively. The combination principle of optical modulation and photoelectric detection technology and the existing technology are analyzed, and the coding mode of underwater visible light communication is compared and analyzed.
(b) the optical transceiver link based on 532nm laser and photomultiplier is designed. According to the selected devices, the optical receiving circuit, the conditioning circuit, the coupling circuit, the level conversion circuit, the MCU control circuit are designed, and the software of single-chip microcomputer and the host computer are written, and a complete underwater visible light transceiver platform is set up.
(c) in view of the current centralized coding methods, the communication modulation of various encoding methods is realized by using single chip software, including direct modulation (OOK), Manchester code (ManchesterCoding), 4 bit and 16 bit pulse position modulation (PPM).
(d) the laboratory test and underwater communication experiment are designed. The performance characteristics of the visible light in the communication coding and the propagation characteristics in the water medium are more intuitively understood, and the experimental objects are evaluated and measured by a quantified evaluation.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.3

【参考文献】