【作者】 王志铭；

【导师】 许昌如；

【作者基本信息】 武汉理工大学 ， 交通信息工程及控制， 2003， 硕士

【摘要】 随着卫星应用技术的发展和市场需求的扩大，当前卫星应用出现如下趋势： 1．为了获得新的频率资源、更高的数据带宽、以及更小巧轻便的天线，卫星使用频率向Ku、Ka波段转移。由于在Ku频段上功率通量密度不受限制，而且信号波长短，同样口径天线的增益要比C频段高，因而采用较小口径的天线(0.5～1.2m)就能支持多路实时视频传输，已成为当前卫星通信的发展方向。Ka波段的试验卫星如ETS-Ⅱ(日)、Olympus(欧洲)、ITALSAT(意)、ACTS(美)等已经证实了ka波段卫星通信的可能性，所采用的信道编码、点波束、数据速率调整等抗雨衰关键技术都已成熟，估计第一颗商用通信卫星将会在数年内投入使用。 2．转发器租用费用日益降低，目前Ku频段转发器租金为1MHz每年4.5-5万美元，租用一个卫星转发器的年租金约为150～200万美元。 3．赋形波束，点波束、信号空中交换与处理等技术都开始得到广泛运用。 在此背景下，卫星应用领域也逐步扩大，从最早军用到商用、到目前家用市场、从固定通信扩大到移动通信等。 本课题为移动环境(比如轮船，车辆等)下进行卫星通信设备中的一个组成模块，主要目的是在卫星天线指向可能的目标卫星后确认是否为所需对象，同时在设备进行步进跟踪时提供信号电平反馈。 论文共分六章：第一章介绍了一般固定卫星通信的典型方式和一些相关参数，说明了移动通信技术的特殊之处，介绍了目前典型移动卫星通信产品的运用和技术现状，并对论文的意义作了详尽的阐述，第二章对同步卫星可供识别的特征包括地理方位、信标信号、信号频谱、解码后数据流特征等进行了分析和探讨，说明使用频谱作为识别特征的优点和通用性。然后选定一颗卫星作为识别对象，分析所选定卫星信号的功率谱并寻找可供用于识别的特征并论证其可靠性。论文第三章设计了频谱特征的提取方法和线路框图并选取适当易得的器件构建硬件线路。论文第四章采用神经元网络(BP)构建了相应的频谱特征识别模型。论文第五章为模型的软件和系统实际演算的结果和对结果进行的讨论。最后，论文介绍了目前模块的实际运用情况并对本课题值得后续研究的方面进行了讨论。 本课题所研究的识别系统已经在北京北方波尔科技有限公司的移动卫星接收系统中得到运用并取得满意结果，其中的精确识别限于单片机的处理能力和成本考虑目前仅有模拟演算结果，但我们有理由相信，由于计算芯片处理能力卫星识别系统的研究与开发的不断提高和双向通信对精度要求的升级，基于BP模型的识别系统也会得到运用。更多还原

【Abstract】 With the development of satelliate technology and market, in nowadays, trends of satelliate appear as follow:1. In order to get new frequency source, high-speed transport velocity and small portable aperture antenna, ku-band has become far-reaching application. As we know, under the equal aperture, antenna gain is in direct ratio to signal wavelengh. A small antenna (0.5-1.2m) can perform communication of several line real-time audio and video in KU band. A series of ka-band propagation experiments supported by ETS-II (Japan) ,Olympus (Europe), ITALSAT (Italy). ACTS (US) . Techniques such as rain fade mitigation, spot beam and shape beam have been developed . the commercial apply of ka-band satelliate will be soon.2. Transponder rent depressed in evidence. The rent of a ku-band transponder is $ 1.5million-$2million per year.3. Techniques such as spot beam, shape beam and transact in satelliate have been used comprehensively.Thus, the application range of satelliate has extend to commercial, household and mobile communicate.As a module of mobile satelliate communication equipment, it can provide a voltage inverse ratio to crab-angle of antenna bearing, and identify the signal source locked by antenna servo.Six chapters were divided in this paper. The present condition of the immobile satelliate application and the peculiarity of mobile satelliate communicate were reviewed in chapter 1. The paper explain the significance of the theme. The identification feasibility of several characteristics such as magnetic azimuth, beacom, frequency spectrum and data stream were evaluated in chapter2. we also choose a satelliate as identification sample, analyse it’s spectrum characteristics that can be easy identified. We bring forward the frame of module and bottom-layer program in chapters. By the means of Artificial Neural Networks (Backpropagation), we constitute the identify algorithm in chapter4. Chapters provides the software of algorithm and the result of operation.At last chapter, we introduce the commercial use and possible improvement of the module.The module and preliminary-identify program has been used in the equipment of Beijing Boolean Technologies Co. Because limited by the speed of singlechip and cost, advanced identify software is simulate in PC* With the precision demand of two-way equipment, advance identify model should be used extensively.更多还原