摘要随着电子侦察技术的发展，雷达在电子对抗环境中面临着越来越严峻的生存威胁，低截获概率(LPI)雷达正是为了提高战场生存能力而发展起来的。而低截获概率波形设计是实现雷达低截获的主要技术措施之一，也是本文讨论的主要内容。

本文介绍了几种基本雷达信号，如二相编码信号（巴克码序列、M序列、Logistic混沌序列）、均匀脉冲串信号以及步进频率脉冲串信号，分别分析了它们的时域特性和频域特性，进行了模糊函数的推导和模糊图的绘制，并且对模糊图进行了切割和比较。在此基础上，进一步研究了一种复杂的调制信号——PCSF（Phase Coded Stepped Frequency）信号，即以均匀脉冲串信号为基础，脉内采用二相编码进行调相、脉间采用步进频率进行调频。本文也对这种复合信号进行了时域、频域分析和模糊函数的分析以及模糊图的绘制。通过与前面分析的基本信号的对比，可以发现复合信号具有良好的低截获性能。最后简单分析了信号匹配处理的知识，包括匹配滤波器的设计等等。64456

毕业论文关键词   低截获概率(LPI)雷达  二相编码信号  均匀脉冲串信号  步进频率脉冲串信号  PCSF信号  模糊函数  匹配滤波器

毕业设计说明书（论文）外文摘要

Title  LPI radar signal analysis based on complex modulation                     

Abstract With the development of electronic reconnaissance technology, radars are facing more and more serious threat of survival. LPI radars are developed in order to improve the survivability in battlefield. LPI waveform design is one of the main technical measures to realize the LPI radars, and is the main content of this thesis.

Firstly, some basic signals are introduced, such as bi-phase coded signal(barker sequence, M sequence code sequence and Logistic sequence), uniform pulse train signal and stepped frequency pulse train signal. Their time feature and frequency feature are analyzed respectively, ambiguity functions are derived, ambiguity graphics are drawn, and graphics are cut. Then based on those, a new kind of complex modulation signal is introduced-- Phase Coded Stepped Frequency signal, namely, based on the uniform pulse sequence signal, bi-phase coded is used to modulate phase in every pulse, stepped frequency is used to modulate frequency among pulses. Through the same analysis above, the PCSF signal has very excellent performance and has a very good LPI property. In the end, the signal matching processing knowledge is simply introduced, including the design of the matched filter and so on.

Keywords  LPI radar   Bi-phase coded   Uniform pulse train signal Stepped-frequency pulse train signal   PCSF signal  Ambiguity function   Matched filter

 目   次

1 绪论 1

1.1 研究的背景与意义 1

1.2 国内外研究现状 1

1.3 本文安排 3

2 模糊函数 4

3 一些简单信号的基本性质 8

3.1 相位编码信号 8

3.1.1 M序列 9

3.1.2 巴克序列