角误差信号解调技术研究与实现

发布时间：2018-01-11 13:25

本文关键词：角误差信号解调技术研究与实现　出处：《南京理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：角误差信号解调技术是卫星通信领域中尤其是中继卫星系统中的一项核心技术,该技术具有较好的实时跟踪性,较小的动态滞后性等优点。随着卫星通讯技术领域的不断扩展,在信噪比低、多普勒变化范围大、多普勒频移速率快的条件下,通过数字方式实现角误差信号解调,成为角跟踪接收机实现的难点和重点。本文首先分析了角误差信号解调技术的基本原理,介绍了单脉冲单通道角跟踪接收机的基本结构。紧接着提出了角误差信号解调的方法,包括同步检波方法和包络检波方法,并对同步检波过程中用于载波捕获的FFT频率估计算法和用于载波跟踪的锁相环技术进行了仿真,结果说明了 FFT频率估计算法利于后续锁相环进行载波跟踪,三阶锁相环能快速准确跟踪载波频率。介绍了四相调制角跟踪接收机的工作原理,重点对四相调制单载波信号、四相调制宽带信号,在不同信噪比条件下进行角误差信号解调仿真,分析结果可以看出在低信噪比条件下同步检波对单载波中频信号和宽带中频信号的解调性能比包络检波的解调性能好,而且同步检波的解调精度随着平均累加时间增加而提升。最后给出了角误差信号解调数字处理模块的硬件设计,包括系统结构设计,硬件电路功能设计,器件选型及配置电路设计。搭建测试平台对角误差信号解调数字处理模块进行测试,并对测试结果做出分析,结果表明本课题设计的角误差信号解调数字处理模块的整体性能能够满足工程技术要求,本课题提出的角误差信号解调的数字实现方法是可行的。
[Abstract]:Angle error signal demodulation is a core technology in satellite communication field, especially in relay satellite system, which has good real-time tracking ability. With the expansion of satellite communication technology, with the low signal-to-noise ratio (SNR), large Doppler range and fast Doppler frequency shift rate. The digital demodulation of angle error signal becomes the difficulty and emphasis of angle tracking receiver. Firstly, the basic principle of angle error signal demodulation technology is analyzed in this paper. The basic structure of monopulse mono-channel angle tracking receiver is introduced, and then the demodulation methods of angle error signal are proposed, including synchronous detection method and envelope detection method. The FFT frequency estimation algorithm used in carrier acquisition and the phase-locked loop technology used in carrier tracking are simulated. The results show that the FFT frequency estimation algorithm is propitious to the subsequent PLL for carrier tracking, and the third-order PLL can track the carrier frequency quickly and accurately. The working principle of the four-phase modulation angle tracking receiver is introduced. The four phase modulation single carrier signal and the four phase modulated wideband signal are emphasized. The angle error signal demodulation simulation is carried out under different SNR conditions. The results show that the demodulation performance of single carrier if signal and wideband intermediate frequency signal is better than that of envelope demodulation under the condition of low signal-to-noise ratio. And the demodulation accuracy of synchronous detection increases with the average accumulated time. Finally, the hardware design of the digital processing module of angle error signal demodulation is given, including system structure design, hardware circuit function design. Device selection and configuration circuit design. Build a test platform for diagonal error signal demodulation digital processing module for testing and analysis of the test results. The results show that the whole performance of the digital processing module of angle error signal demodulation can meet the requirements of engineering technology, and the digital realization method of angle error signal demodulation proposed in this paper is feasible.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN927.2

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