线性调频雷达典型有源干扰抑制技术研究

发布时间：2018-03-01 19:02

本文关键词： 干扰抑制线性调频雷达噪声调幅干扰转发式密集假目标干扰灵巧噪声干扰参数估计　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：雷达干扰抑制技术一直是雷达信号处理领域最为重要的研究方向之一,雷达系统必须在复杂的电磁干扰环境中,依然能保持正常运转,才能在实际电子对抗中赢得优势。然而,随着高速数字电路技术的快速发展,雷达系统所面临的电磁干扰环境日益恶劣。传统的压制式干扰依然在发挥作用,基于数字射频存储器技术和直接数字合成技术的欺骗性干扰又给现代雷达系统带来了新的挑战,一些新型的、更加复杂的干扰样式更是不断涌现。因此,如何增强雷达系统抗有源干扰的能力,受到广泛的研究和关注。本文基于线性调频体制的雷达系统,围绕典型的有源干扰样式,对干扰抑制技术展开了深入分析和研究。重点研究了噪声调幅干扰、转发式密集假目标和卷积式灵巧噪声干扰的抑制方法和实现算法,主要的工作和贡献有:1)噪声调幅干扰的抑制提出了一种基于最大似然的自适应迭代参数估计方法,并通过频域对消方法抑制干扰。针对噪声调幅干扰的数学模型,研究了其似然函数的特点,给出了一种基于修正傅立叶系数插值的参数粗估计方法,理论分析了该方法的参数估计性能以及参数估计的克拉美罗下界;设计了噪声功率比的估计方法,进而提出了基于最大似然准则和梯度下降策略的参数精估计迭代算法,并通过理论分析得到了迭代的收敛条件。仿真实验表明,所提方法的参数估计均方误差渐进无偏逼近克拉美罗下界,优于已有的其它方法,噪声调幅干扰的抑制效果明显增强。2)转发式密集假目标干扰的抑制针对完全转发干扰样式,分析了实际数据中干扰的特点,建立了干扰的数学模型;针对模型中多分量线性调频干扰时域部分混叠的特点,提出了一种多步干扰消除的参数估计方法,分析了参数估计的克拉美罗下界;在此基础上,通过干扰重构和对消的方式来抑制干扰。仿真实验验证了所提算法参数估计的均方误差逼近克拉美罗下界,实际数据的结果表明了所提干扰抑制方法的有效性及适用条件。针对部分转发干扰样式,总结了不同干扰样式的共同特点,建立了统一数学模型;针对模型中不同部分转发分量拼接的特点,提出了一种基于集合经验模态分解的参数估计方法,并通过干扰重构和对消的方式来抑制干扰。仿真结果显示,所提方法的干扰抑制性能优于其它已有方法。针对雷达在实际工作中会受到通信信号干扰的情况,分析了实际数据中无意通信干扰的特点,对通信干扰进行了建模,进而提出了一种基于多维经验模态分解的批处理方法,将干扰分解到不同的多维本征模态函数中进行抑制。经由仿真实验,验证了该算法能够有效抑制通信信号的干扰。3)卷积式灵巧噪声干扰的抑制针对干扰与目标回波移频的不同,分析了卷积式灵巧干扰经脉冲压缩后调频斜率、移频以及峰值位置之间的关系,提出了一种基于污迹谱的方法,分辨出真实目标回波。通过仿真实验,验证了所提方法在干扰表现不同特征时的干扰抑制效果,且该方法的干扰抑制性能优于其它已有方法。通过分析灵巧噪声干扰各干扰分量时延相关性的特点,提出了一种基于原子分解的方法,分离目标回波和干扰。通过仿真实验结果,验证了所提方法的干扰抑制效果。
[Abstract]:Interference suppression techniques in the field of radar signal processing radar has been one of the most important research direction, radar system must be in the complex electromagnetic interference environment, can still maintain the normal operation, can win the advantage in actual electronic warfare. However, with the rapid development of high-speed digital circuit technology, electromagnetic interference environment of radar system in the face of increasingly bad. The traditional jamming is still in play, the deception jamming of digital radio frequency memory technology and direct digital synthesis technology based on the modern radar system to bring new challenges, some new, more complex interference patterns are emerging. Therefore, how to enhance the ability of anti active jamming radar system, widely the attention and research. In this paper, the radar system based on linear frequency modulation system, around the active interference pattern of the typical interference suppression technology The in-depth analysis and research. Focus on the noise amplitude modulation jamming suppression method, forward type dense false target and smart noise jamming and convolution algorithm, the main work and contributions are: 1) noise suppression jamming is proposed an estimation method of adaptive iterative parameters based on maximum likelihood, and through frequency domain cancellation interference suppression method. According to mathematical model of noise amplitude modulation jamming, the characteristic of the likelihood function, a parameter estimation method of coarse modified Fu Liye interpolation coefficients are given based on the theoretical analysis and the parameter estimation performance of Cramer Rao bound parameters of the estimation method; design method to estimate the noise power ratio, then put forward the maximum likelihood criterion and gradient parameters estimation method based iterative algorithm, and the convergence condition of iteration through theoretical analysis. Simulation results show that the The proposed method parameter estimation mean square error asymptotically unbiased approximation Cramer Rao lower bound, is better than other methods, the inhibitory effect of noise amplitude modulation jamming enhanced.2) transponder dense false target interference suppression for completely forward jamming, analyzes the disturbance characteristics of dry real data, establishes a mathematical model for interference; in the model of multi-component LFM interference in time domain aliasing characteristics, a method is proposed to estimate the elimination of multi step interference parameters, analysis of parameter estimation Cramer Rao bound; on this basis, and to eliminate the way to curb the interference reconstruction. Simulation results show the proposed algorithm for parameter estimation are square error approximation Cramer Rao lower bound, the results show the validity and the applicable conditions of the proposed interference suppression method. Aiming at the repeater jamming style, summarizes the different kind of interference The common characteristics, the establishment of a unified mathematical model; according to the characteristics of different parts of the mosaic model forwarding component, proposes a parameter estimation method based on Ensemble Empirical modedecomposition, and through the interference reconstruction and cancellation method to suppress the interference. The simulation results show that the performance is better than other existing methods of interference suppression of the proposed method for radar will be communication signal interference in the actual work, analyzes the characteristics of unintentional communication interference in real data, a model of communication interference, and then proposes a multi-dimensional batch processing method based on empirical mode decomposition, the interference suppression is decomposed into different multidimensional intrinsic mode function through. The simulation experiment proves that the algorithm of.3 interference can effectively inhibit communication signals) inhibit the convolution of smart noise jamming against interference and target echo frequency shift of different points Analysis of the convolution of the pulse compression of smart jamming frequency slope, the relationship between frequency shift and peak position, put forward a method based on spectral stain, distinguish the true target echo. Through simulation experiments, the method was verified by the interference performance of different features in the interference suppression effect and better performance than other existing methods of inhibiting interference and the method. Through the analysis of the characteristics of smart noise jamming the interference component correlation of delay, proposes a method based on atomic decomposition, separation of target echo and jamming. The simulation results validate the proposed method, the interference suppression effect.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN974

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