文档介绍：上海交通大学
硕士学位论文
基于FPGA的卫星通信码分多址接收机的研究与实现
姓名:钟卫强
申请学位级别:硕士
专业:电子与通信工程
指导教师:袁焱;朱德民
20100501
上海交通大学工程硕士学位论文摘要

基于的卫星通信
码分多址接收机的研究与实现

摘要

低轨道小卫星通信系统由于其固有的特点在国民经济和国防建设中
越来越受到重视。本文作者参加了某低轨道卫星通信系统地面检测设备
码分多址接收机的研制工作,作者以该课题为背景,深入研究了接收机
的系统结构和算法,实现在大多普勒环境下信号的快速捕获和同步。
本文提出了通过分段相关法扩大码分多址接收机相关器的频差容
限,从而大大减小捕获时间的方法,并提出了一种相位补偿的方法减小
相位抖动和波形畸变,依据时钟同步电路产生的超前或滞后信号,采用
相位补偿的方法对其因超前或滞后信号引起的数控振荡器本地载波信号
的相位抖动和波形畸变,建立一个相位补偿模块,用以减小相位抖动和
波形畸变。
本文还介绍了如何用芯片实现码分多址解调器各关键模块,包
括数字下变频、匹配滤波、扩频码同步、时钟同步、载波恢复等过程。
最后文章还给出了实测记录,各项指标均满足任务书要求。

关键词:低轨道小卫星,码分多址,多普勒频移,扩频码,同步

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上海交通大学工程硕士学位论文 ABSTRACT

THE RESEARCH AND REALIZATION OF A CDMA RECEIVER OF
MUNICATION BASED ON FPGA

ABSTRACT

The LEO(Low Earth Orbit)micro-munication system has a
bright future in the areas of the state economy and the state defenses
because of its inherent characteristics. Based on both the working of the Earth
Testing System which adopted CDMA system and the LEO Micro-Satellite
Earth Receiver, the paper researches the structure of the system and
algorithm,and achieves fast- capturing and tracking under the environment of
the large DFS (Doppler-Frequency-Shift).
This paper brings out a method of expanding the range of the
frequency-differences in the interrelated modules in order to reduce the
capturing-time cost. Also, a method of the pensating to reduce the
phase-disturbing and wave-distortion is put forward. According to the
pro-signal or the lagged-signal, a pensating module can be set up to
reduce the phase-disturbing and wave-distortion es from the
module of the numerical control vibration.
And the paper introduces the method of making some important modules,
including the processes of DDC (Digital down conversion), matched filter,
code-synchronism, clock- synchronism and carrier recovery, etc.
At last, the records are shown out, and all the parameters of the system
are in the regular ranges.