阵列相干信号的高分辨测向技术

发布时间：2018-06-12 14:16

本文选题：阵列相干信号 + 宽带信号　；参考：《哈尔滨工程大学》2014年博士论文

【摘要】：本文针对阵列相干信号的高分辨测向技术,着重研究了不同的窄带解相干算法对方位估计性能的影响以及宽带相干信号中聚焦矩阵的求取原则和一些新颖的宽带聚焦方法。论文的主要研究内容和创新点如下:研究了窄带相干源方位估计方法,针对算法在低信噪比时估计偏差较大的问题,设计一种数据处理方法,利用多次实验结果的均值作为参考,筛选出符合条件的实验结果,从而提高低信噪比时方位估计的准确性。在分析了单快拍相干源方位估计方法的基础上,给出一种与信源相关度和快拍点无关的单快拍方位估计方法,并针对单快拍方法在低信噪比的性能下降问题,提出了一种快拍数据累加方法,该方法利用发射信号的周期性,选取每个周期的相同快拍点进行累加,仿真结果表明提出的方法可以有效改善单快拍方法在较低信噪比下的估计性能。研究了基于角度预估和无需角度预估的宽带聚焦矩阵构造方法,讨论分析了不同聚焦矩阵构造方法对方位估计性能的影响,提出了一种离散阵列流形宽带聚焦方法,用离散化的阵列流形矩阵构造聚焦矩阵,不仅无需角度预估,而且避免了阵列流形内插法中贝塞尔函数的计算,有效地降低了运算复杂度,仿真结果验证了提出方法的有效性。研究了无需构造聚焦矩阵的空间重采样方法和空时DFT投影方法,将数据重构的思想引入宽带MVDR算法中,仿真实验结果表明,对于宽带MVDR算法而言,数据重构方法比起FFT插值法具有更低的分辨信噪比门限和均方根误差。提出一种改进的空时DFT投影算法,通过适当提高采样频率可以有效改善空时DFT投影方法的方位估计性能,结合运算量小的ESPRIT-like算法,提高实时性,并且其性能优于空间重采样方法。研究了基于贝叶斯聚焦的宽带相干源方位估计方法,提出了一种酉聚焦贝叶斯方法,可以根据不同的预估角度和预估波束宽度调整加权函数,通过仿真实验证明了提出的方法可以有效减少方位预估的计算量,获得比RSS算法更加优越的性能。
[Abstract]:In this paper, the influence of different narrowband decoherence algorithms on the azimuth estimation performance, the principle of obtaining the focusing matrix in wideband coherent signals and some novel wideband focusing methods are studied for the high-resolution direction-finding techniques of array coherent signals. The main contents and innovations of this paper are as follows: the azimuth estimation method of narrowband coherent source is studied, and a data processing method is designed to solve the problem that the estimation deviation of the algorithm is large when the SNR is low. By using the mean value of multiple experimental results as a reference, the suitable experimental results are selected to improve the accuracy of azimuth estimation at low signal-to-noise ratio (SNR). Based on the analysis of single rapid-shot coherent source azimuth estimation method, a single rapid-shot azimuth estimation method, which is independent of source correlation and rapid-beat point, is presented, and the performance of single-rapid-shot method in low SNR is also discussed. A rapid-beat data accumulation method is proposed, in which the periodicity of the transmitted signal is utilized, and the same beat point of each period is selected to accumulate. Simulation results show that the proposed method can effectively improve the estimation performance of single shot method at low SNR. The method of constructing wideband focusing matrix based on angle prediction and without angle estimation is studied. The influence of different focusing matrix construction methods on the performance of azimuth estimation is discussed. A broadband focusing method based on discrete array manifold is proposed. Using discrete array manifold matrix to construct focusing matrix, not only does not need angle prediction, but also avoids the calculation of Bessel function in array manifold interpolation method. The computational complexity is reduced effectively. The simulation results show that the proposed method is effective. The spatial resampling method and space-time DFT projection method without constructing focusing matrix are studied. The idea of data reconstruction is introduced into wideband MVDR algorithm. The simulation results show that, for wideband MVDR algorithm, simulation results show that, Data reconstruction method has lower resolution SNR threshold and root mean square error than FFT interpolation method. An improved space-time DFT projection algorithm is proposed. By properly increasing the sampling frequency, the azimuth estimation performance of space-time DFT projection method can be improved effectively. And its performance is better than the spatial resampling method. In this paper, a Bayesian focusing method for wideband coherent source azimuth estimation is studied. A unitary focusing Bayesian method is proposed, which can adjust the weighting function according to different prediction angles and estimated beam widths. The simulation results show that the proposed method can effectively reduce the computational complexity of azimuth estimation and obtain better performance than RSS algorithm.
【学位授予单位】：哈尔滨工程大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN911.7

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