LPI雷达信号参数估计与抗干扰性能研究

发布时间：2018-07-04 21:52

本文选题：LPI雷达信号 + 参数估计　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：近年来,电子对抗与反对抗技术发展迅速,现代雷达系统所面临的工作和生存环境更为恶劣,针对雷达的电磁干扰技术得到迅猛发展。因此,复杂电磁环境下雷达信号参数估计及其自身抗干扰性能的研究工作迫在眉睫,具有重要的理论意义和实用价值。本文基于几种典型低截获概率(LPI)雷达信号,针对复杂电磁环境下信号参数估计及其抗干扰性能展开深入研究,主要工作和研究成果如下:首先,介绍了三种主要的有源压制式干扰以及用于LPI雷达信号处理的基础理论,进而提出了一种基于模糊函数和匹配滤波的信号抗干扰性能评估模型。雷达信号的模糊函数及其衍生出的有效面积和切割面积有效分离了信号处理方式、截获解调、干扰方侦收等因素,使得可以从信号自身特征角度对信号抗干扰性能进行定性与定量分析,具有重要的理论价值。同时,通过分析三种干扰下雷达信号匹配滤波前后信干比的改善,验证信号的抗干扰性能。其次,针对常规参数估计方法在低信噪比下性能严重退化的问题,提出了一种基于分数阶自相关和S-RAT(Second order difference based RAT)的P4多相码信号参数估计方法。该方法首先引进分数阶自相关运算,完成P4多相码信号调频斜率的估计。定义了S-RAT,对多相码信号模糊函数沿脊线方向作Radon变换。同时,利用二阶差分算子消除由噪声产生的桥形基底,以提取RAT峰值间隔,得到码元宽度和编码周期的估计。仿真结果表明,该方法对于高斯白噪声下的P4多相码信号具有良好的参数估计性能。最后,研究了复杂电磁环境下LPI雷达信号抗干扰性能评估问题。在前面提出的评估模型的基础上,对几种典型信号进行了仿真研究与分析,包括对称三角线性调频(STLFM)信号、三相编码信号和混沌信号。STLFM信号具有相互交叉的斜刀刃型模糊函数,克服了传统线性调频(LFM)信号的距离多普勒耦合,具有较好的抗射频干扰和调幅干扰能力。三相编码信号具有图钉型模糊函数,由于信号的码元具有周期重复特性,其模糊函数平面呈现出规则排列的尖峰。混沌信号具有近乎理想的图钉型模糊函数,抗干扰性能优良,符合现代雷达系统的要求。
[Abstract]:In recent years, electronic countermeasures and anti anti anti technology have developed rapidly. The work and living environment of modern radar systems are worse. The electromagnetic interference technology for radar has developed rapidly. Therefore, the research on the estimation of radar signal parameters and its self anti-interference ability under the complex electromagnetic environment is imminent, and it has important theory. In this paper, based on several typical low intercept probability (LPI) radar signals, this paper studies the signal parameter estimation and anti-jamming performance in complex electromagnetic environment. The main work and research results are as follows: firstly, three main active suppression jamming and the basic theory for LPI radar signal processing are introduced. Then a model of signal anti-jamming performance evaluation based on fuzzy function and matched filter is proposed. The fuzzy function of the radar signal and the effective area and the cut area derived from the signal can effectively separate the signal processing mode, intercept the demodulation, the interference square detection and other factors, so that the signal anti-jamming performance can be obtained from the signal's own characteristic angle. Qualitative and quantitative analysis is of great theoretical value. At the same time, by analyzing the improvement of the signal's jamming performance before and after the matched filtering of radar signals under the three interference, the anti-jamming performance of the signal is verified. Secondly, a kind of fractional order autocorrelation and S-RA is proposed for the problem that the performance of the conventional parameter estimation method is seriously degraded under the low signal to noise ratio. T (Second order difference based RAT) estimation method of the P4 multiphase code signal parameters. Firstly, the fractional autocorrelation operation is introduced to estimate the frequency modulation slope of the P4 multiphase code signal. S-RAT is defined. The ambiguity function of the multiphase code signal is transformed along the direction of the ridge line. At the same time, the two order difference operator is used to eliminate the bridge generated by the noise. The RAT peak interval is extracted to obtain the estimation of the symbol width and the encoding period. The simulation results show that the method has good parameter estimation performance for the P4 multiphase code signal under Gauss white noise. Finally, the evaluation of the anti-interference performance of the LPI radar signal under the complex electromagnetic environment is studied. On the basis of the simulation research and analysis of several typical signals, including symmetric trigonometric linear frequency modulation (STLFM) signal, three phase coded signal and chaotic signal.STLFM signal with cross cutting edge blur function, which overcomes the distance Doppler coupling of the traditional linear frequency modulation (LFM) signal, and has better anti radio interference and amplitude modulation. The three-phase coded signal has a tack fuzzy function. Because the signal code element has periodic repetitive characteristics, its fuzzy function plane presents the peak of the regular arrangement. The chaotic signal has nearly ideal stud type fuzzy function, and its anti-interference performance is excellent. It meets the requirements of modern radar system.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN957.51

【相似文献】