【作者】 顾冬梅；

【导师】 茅玉龙；

【作者基本信息】 南京信息工程大学 ， 信号与信息处理， 2009， 硕士

【摘要】 在现代十分复杂的电磁环境中,连续波雷达信号作为一种特殊的信号形式,其信号识别和参数提取已越来越得到重视,雷达侦察系统应具有对连续波信号进行分析处理的能力,因此有必要对其信号调制方式识别和调制参数提取技术进行研究。本文主要研究连续波雷达信号的调制方式识别和调制参数提取问题,并进行计算机仿真。首先介绍了连续波雷达信号的各种调制方式,研究了各种信号的基本特征。然后介绍了信号瞬时频率提取算法,本文利用短时傅立叶变换对连续波雷达信号的瞬时频率进行提取。根据连续波信号的频谱宽度识别出非调制连续波信号。提取已调制连续波信号的瞬时频率,对其频谱分析识别出频率调制和相位编码调制连续波信号。调频连续波信号根据其瞬时频率的频谱识别出各种调频方式,相位编码调制连续波信号根据其原信号平方的谱宽识别出二相码和四相码相位调制方式。经仿真,在信噪比较低时,识别正确率仍较高。在正确识别出调制方式基础上对调制参数进行提取,对于非调制连续波信号用修正Rife算法进行载频估计。对于调频连续波信号,对其瞬时频率进行频谱分析来提取调制参数。对于相位编码调制连续波信号,先估计其载频和初相,再进行相关运算,由相关运算的输出提取码元宽度和码序列,仿真结果表明该算法精度较高。更多还原

【Abstract】 In the modern extremely complex electromagnetic environment, as a special form of the signal, the signal identification and parameter extraction of continuous-wave radar signal obtain more and more attention. The radar detection system should have the analyzing and processing ability to the continuous-wave signal, so it’s necessary to research on its signal modulation identification and modulation parameter extraction techniques.The modulation identification and modulation parameter extraction of continuous-wave radar signal are researched in this paper and then the computer simulation is given. Firstly, each modulation of the continuous-wave radar signals is introduced and the basic characteristic of each signal is talked about. And then the instantaneous frequency signal extraction algorithms is introduced and the short-time Fourier transform is adopted to extract the instantaneous frequency of continuous-wave radar signal in this paper.The non-modulated continuous-wave signal is identified according to the spectral width of the continuous-waves signal. The instantaneous frequency of the modulated continuous-wave signal is extracted to identify the frequency modulation or phase-coded modulation continuous wave signal by the analysis of spectral. Each kind of frequency-modulated signal is distinguished by the spectral analysis of instantaneous frequency. Two-phase and four-phase coded modulation continuous-wave signal is identified by the square spectral width analysis of original signal. According to the simulation, the recognition accuracy rate is still high in low signal-to-noise ratio condition.Modulation parameter extraction is based on correct modulation identification. For the non-modulated continuous-wave signal, amend Rife algorithm is used to estimates carrier frequency. Regarding frequency modulated continuous wave signal, the spectral analysis of instantaneous frequency is used to extract modulation parameter. For the phase-coded modulation continuous-wave signal, first estimates its carrier frequency and phase, then get a correlation operation, the element width and the code sequence is extracted by the output of correlation operation. By simulation, we can conclude that this algorithm has a high precision.更多还原