【作者】 胡启迪；

【导师】 柯熙政；

【作者基本信息】 西安理工大学 ， 通信与信息系统， 2009， 硕士

【摘要】 以激光作为信息载体的大气激光通信技术以其高带宽、高码率、高保密性、低功耗等优点成为通信技术发展的新方向,具有良好的应用前景。近些年来,该技术受到了世界各国的重视,并得到了迅速的发展。但是,大气激光通信由于信号光束窄、传输距离长等原因,给通信链路的建立和保持造成了极大的困难。因此,在大气激光通信中,必须建立一套捕获、瞄准和跟踪(Acquisition、Poniting and Tracking,简称APT)系统来防止通信链路中断,从而保证整个通信过程的顺利进行。近年来,从各国激光通信的发展情况来看,ATP系统是目前激光通信中最为关键的一项技术,可以说它是进行可靠通信的前提。在APT系统中,信标光捕获是建立通信链路的第一步,其一般过程为：大气激光通信双方先搜索对方的信标光,当信标光进入视场后从对方信标光的光斑中获取对方的位置信息,然后进行方位调整,最终把天线表面积上的法线矢量调整到与光束的到达角一致。其中信标光的捕获判定以及位置信息提取属于光斑检测技术。本文主要的研究对象是信标光捕获过程中的光斑检测技术。文中首先综述了研究大气激光通信的意义以及国内外在激光通信中的研究进展,进而阐述了APT技术的必要性和重要性。其次,重点分析研究了APT系统中的捕获技术,在此研究基础上对可用于信标光光斑检测的几种探测器进行了分析。最后,着重分析了PSD与CCD这两种探测器在信标光光斑检测技术中的具体应用。光斑检测探测器的主要作用就是进行信标光的捕获判定及信标光光斑重心提取。PSD在光斑检测技术中的具体使用方法就是通过对PSD各输出引脚上的光电流进行采集以及相关运算,进行捕获判定以及光斑重心位置提取,实际上就是PSD信号的采集与处理过程。CCD采集到的是图像信息,所以使用CCD作为光斑检测探测器,在进行光斑检测过程中所涉及到的工作实际上就是对图像的处理。基于对PSD和CCD的原理、特性以及使用方法的分析,文中设计了PSD信号采集与处理电路以及用于信标光光斑检测的CCD图像处理软件,并且进行了仿真实验,给出了仿真实验结果。从结果中可以看出方案的可行性以及不足,可为后续课题提供参考。更多还原

【Abstract】 The laser communication in atmosphere which use laser as an information carrier has a good application prospects and become the new direction of communication technology development because of its wide bandwidth, high data rate, good secrecy and lower power consumption. In recent year, this technology has been paid much attention by many countries, and has been developing rapidly. But, laser communication in atmosphere is much difficult to establish and maintain a communication links because of the limited width of laser beam and the long communication distance. So it is necessary to build an APT (Acquisition, Pointing and Tracking) subsystem to prevent the loss of communication signal from the failure of links. From the overview of the development of optical communication in the last two decades, we can see that APT technology is the most important technology, so APT technology is the precondition of reliable communication. In the APT system, to capture beacon is the first step in the establishment of communication links, and its general process is that First of all, both Terminals of laser communication in Atmospheric to search each other’s beacon, When the beacon light into the field of view, they obtain position information from each other’s Beacon spot, then Adjust the position, Finally adjust the normal vector of Antenna surface area and arrival angle of beam to the same direction.The main object of study in this paper is spot detection technology in the process of capture beacon. At the beginning of this paper, it reviewed the purpose of carrying out optical communication research and the result that many countries and enterprises gained, and introduced the significance and the necessity of APT. Secondly, it analyzed and researched carefully the acquisition technology in APT system, Based on this research, it analyzed several detectors that can be used to capture beacon. At the end, it analyzed especially specific application of PSD and CCD in the process of capture beacon.The main function of capture probe is to detect the beacon spot. Application of PSD in the process of capture beacon is that to collect photocurrent and related operations from the output pins of PSD in order to make acquisition determination and extract the location of the focus spot, actually that is process of PSD signal acquisition and processing. The information which CCD collected is images, so if use CCD as a beacon light capture detector, the related work is Image Processing.Based on the analysis of principles, characteristics and the methods of use of PSD and CCD, in this paper, it designed the PSD signal acquisition and processing circuit and the CCD image processing software for detecting beacon spot, and the simulation and experimental results have been given. The results can prove the feasibility and the lack of. It’s the reference of follow-up subject.更多还原