【作者】 汪玲；

【导师】 陈天麒；

【作者基本信息】 电子科技大学 ， 电路与系统， 2007， 博士

【摘要】 非平稳信号作为现实生活中普遍存在的信号形式,其分析处理在现代信号处理中占有特殊重要的地位。建立在平稳窄带假设基础上的传统阵列信号处理方法在分析处理这类信号时受到局限。在多通道阵列信号处理中,充分利用现代信号处理的优秀成果,将非平稳信号处理手段与传统的空域处理相结合,实现非平稳信号时频特征与空域参量联合估计,成为阵列信号处理发展的必然趋势。本文围绕非平稳阵列信号建模、线性类时频分析、宽带非平稳雷达信号多参量估计、信号个数估计、阵列校正等阵列信号处理问题展开深入研究,主要工作和贡献有:1、研究了基于窄带阵列模型的空间进化谱DOA估计问题。提出了基于联合块对角化方法和波束形成技术的高速高分辩率的信号到达角估计方法;针对时频平面不可分离的相干非平稳信号,提出了基于对称阵列的解相干方法。2、研究了线性调频信号参量估计和宽带雷达信号的空间谱估计问题。提出了基于线性调频类变换的高精度估计线性调频信号时频参量的方法;针对宽带相干信号模型,利用正交投影子空间方法和Toeplitz对角化方法估计信号到达角,并实现阵列位置误差校正;从波束空间角度出发,提出了不随频率变化的波束形成矩阵构造方法,并应用于宽带非平稳雷达信号DOA估计。3、研究了非平稳雷达信号多维参量联合估计问题。利用时频高阶矩谱估计正弦调频信号频率参量;针对相位编码信号,研究了时空欠采样条件下时频空三维参量联合估计的方法;提出了基于短时Fourier变换的相位编码信号时频参量估计方法,并能分辨二相编码信号和四相编码信号;结合波束空间ESPRIT算法,提出了基于空间非均匀L阵时空欠采样条件下,相位编码信号的时频空三维参量无模糊联合估计方法。4、研究了宽带信号个数估计和不同噪声背景下信号个数估计的关键问题。提出了基于频域bootstrap方法的宽带信号个数估计方法,并结合盖氏圆方法,提出了色噪声下宽带信号个数估计方法。5、研究了宽带非平稳信号条件下阵列误差的自校正方法。利用辅助阵元,针对存在阵元通道幅相误差、阵元位置误差、阵元间互耦的阵列,提出了宽带非平稳信号模型下阵列误差自校正的方法。更多还原

【Abstract】 The analysis methods of nonstationary signals, which are widely exist in our real life, play an important role in modern signal processing. When dealing with the nonstationary signals, the performance of traditional methods in array signal processing may degrade heavily because of the narrowband and stationary signals assumptions. The aim of this dissertation is to use the achievements in modern signal processing, and to combine nonstationary signal processing with array/multiple channel signal processing for joint spatial and time signatures estimation of nonstationary radar signals. This is also an advanced and challenging problem to the array signal processing. We focus on array signal modeling, time-frequency analysis method, parameters estimation of wideband nonstationary radar signals, sources number estimation and array calibration to array processing in the presence of nonstationary signals. The main contributions of this dissertation are concentrating as follows:1. The application of spatial data-adaptive evolutionary spectral in nonstationary radar signal are discussed. A DOA estimation method of nonstationary radar signals is proposed by time-frequency analysis method and Joint-block diagonalization method. An algorithm for improving the angle resolution is proposed based on beamforming technique. A new direction finding method of coherent signals is proposed by constructing Toeplitz matrix using the output of symmetry array.2. The LFM transform and spatial spectral estimation method of wideband arrays model is discussed. A time-frequency parameters estimator of LFM signals is proposed using LFM transform. A DOA estimation technique of wideband array signals is proposed by orthogonality of projected subspaces and Toeplitz diagonalization method. The proposed method can calibrated the array position errors and deal with coherent signals. A frequency invariant beamforming method underling beamspace is proposed to analyze wideband nonstationary array signals.3. A joint estimation technique of time spatial parameters is discussed in undersampling conditions for non-linear frequency modulation signals. A time-frequency estimator is proposed for sine frequency modulation signals using high order cumulating of Wigner-Ville distribution. A new method to estimate the parameters of phase-coded signals is proposed by short-time Fourier transform. This method can distinguish between the binary-phase-coded signals and quadrature-phase-coded signals. And a joint estimation algorithm for the time spatial parameters of the signals is proposed using beamspace ESPRIT method and nonuniform L-arrays.4. The source enumeration of wideband signals underling white/color noise conditions is discussed. A new detection method of nonstationary sources is proposed using frequency domain bootstrap techniques. The proposed method can estimate the sources number under color noise by combining the bootstrap and Gerschgorin disk estimation methods.5. The method of array auto-calibration for wideband sources is discussed. A new method is proposed. This method can calibrate the unknown error of sensor gain and phase, array shape perturb and sensors coupling by assistant sensors.更多还原