时域宽带恒定束宽波束形成方法研究
发布时间：2019-06-17 18:48
【摘要】：随着阵列信号处理的日益发展,其在现代信号处理的地位也越加显著,并在诸多领域,如:雷达、通信、射电天文以及医学诊断等得到了广泛应用。通过对传感器阵列赋以不同的系数获得最优的输出性能是自适应波束形成的目标,也是阵列信号处理的重要组成部分之一。宽带信号带宽足够大能够传输很大的信息量,并且混响背景相关性弱不容易受到信道传输过程的影响,在目标的检测、参数估计和目标特征的提取这些方面上更具有优势,然而传统的宽带信号波束形成设计中会因为带宽内子带频率的不同导致入射信号来波方向在波束主瓣宽度内的其他方向上时出现失真,在实际应用中无法满足频率上恒定束宽,这会导致算法性能的下降。因此,宽带恒定束宽波束形成算法具有很大的实际意义。并且当期望宽带信号和干扰信号共同在远场平面入射时,如何抑制干扰信号和噪声信号的影响也是恒定束宽波束形成中的一个重要问题。本文对恒定束宽波束形成算法的实现和波束图中干扰方向上的零陷形成进行了深入研究。首先,在聚焦变换思路下把宽带信号划分后的不同频率子带上的数据通过聚焦变换矩阵聚焦到一个参考频率上,推导了宽带信号各个子带频域数据的输出矩阵形式和RSS方法下的聚焦变换矩阵表达式,之后通过MVDR波束形成方法设计得到频率不变恒定束宽并且具有很好零陷区域的波束形成器。其次,利用SRV约束实现恒定束宽最低旁瓣波束形成,然后在满足期望信号指定来波方向上波束输出增益最大和干扰信号来波方向零陷抑制的条件下,分析宽带恒定束宽波束形成中最佳权矢量的设定,得出了满足设计需求的SRV约束下恒定束宽MVDR最低旁瓣波束形成,并对其进行改进得到新算法,仿真证明改进后的方法在小采样数和较高输入SNR的情况下具有更好的输出性能。再次,重点研究了最差环境下波束形成算法,详细推导了波束形成算法的形成过程,引入椭球体约束集实现对任意方向向量失配的信号的无失真接收并将优化问题化简成为凸优化问题,采用内点法求取最优的权重向量。最后,将该波束形成算法用于宽带恒定束宽波束形成算法中,提出了导向向量失配下恒定束宽波束形成算法,经过仿真研究,验证了该算法对小采样样本引起的采样自相关矩阵误差以及方向向量失配都具有很好的鲁棒性,并且可以实现带宽上恒定束宽,在干扰信号来波方向上形成较大的零陷深度,波束形成系统有很好的输出性能。
[Abstract]:With the development of array signal processing, its position in modern signal processing is becoming more and more prominent, and it has been widely used in many fields, such as radar, communication, radio astronomy and medical diagnosis. It is the target of adaptive beamforming to obtain the optimal output performance by assigning different coefficients to the sensor array, and it is also one of the important components of array signal processing. The broadband signal bandwidth is large enough to transmit a large amount of information, and the reverberation background correlation is not easily affected by the channel transmission process, so it has more advantages in target detection, parameter estimation and target feature extraction. However, in the traditional broadband signal beamforming design, due to the different subband frequency in the bandwidth, the incident signal will be distorted in other directions in the main lobe width of the beam, and the constant beam width in the frequency can not be satisfied in practical application, which will lead to the degradation of the performance of the algorithm. Therefore, the broadband constant beam width beamforming algorithm has great practical significance. When the broadband signal and the interference signal are expected to incident in the far field plane, how to suppress the influence of the interference signal and the noise signal is also an important problem in the constant beam width beamforming. In this paper, the realization of constant beam width beamforming algorithm and the zero notch formation in interference direction in beam graph are deeply studied. Firstly, under the idea of focusing transformation, the data on different frequency subbands of broadband signal are focused on a reference frequency by focusing transformation matrix, and the output matrix form of frequency domain data of each subband of broadband signal and the expression of focusing transformation matrix under RSS method are derived. then the beamformer with constant frequency beam width and good zero notch region is designed by MVDR beamforming method. Secondly, the constant beamwidth minimum sidelobe beamforming is realized by using SRV constraint, and then the optimal weight vector setting in broadband constant beamwidth beamforming is analyzed under the condition of satisfying the maximum output gain of the beam output and the zero notch suppression of the interference signal in the specified incoming direction of the desired signal, and the constant beamwidth MVDR minimum sidelobe beamforming under the SRV constraint to meet the design requirements is obtained, and a new algorithm is obtained. The simulation results show that the improved method has better output performance under the condition of small sampling number and high input SNR. Thirdly, the beamforming algorithm in the worst environment is studied, and the forming process of the beamforming algorithm is deduced in detail. The ellipsoid constraint set is introduced to realize the distortionless reception of the mismatched signal in any direction vector, and the optimization problem is simplified into a convex optimization problem. The optimal weight vector is obtained by the interior point method. Finally, the beamforming algorithm is applied to broadband constant beamwidth beamforming algorithm, and a constant beamwidth beamforming algorithm under guidance vector mismatch is proposed. The simulation results show that the algorithm has good robustness to the sampling autocorrelation matrix error and direction vector mismatch caused by small sampling samples, and can achieve constant beam width on bandwidth and form a large zero-notch depth in the wave side of the interference signal. Beamforming system has good output performance.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN911.7
本文编号：2501186
[Abstract]:With the development of array signal processing, its position in modern signal processing is becoming more and more prominent, and it has been widely used in many fields, such as radar, communication, radio astronomy and medical diagnosis. It is the target of adaptive beamforming to obtain the optimal output performance by assigning different coefficients to the sensor array, and it is also one of the important components of array signal processing. The broadband signal bandwidth is large enough to transmit a large amount of information, and the reverberation background correlation is not easily affected by the channel transmission process, so it has more advantages in target detection, parameter estimation and target feature extraction. However, in the traditional broadband signal beamforming design, due to the different subband frequency in the bandwidth, the incident signal will be distorted in other directions in the main lobe width of the beam, and the constant beam width in the frequency can not be satisfied in practical application, which will lead to the degradation of the performance of the algorithm. Therefore, the broadband constant beam width beamforming algorithm has great practical significance. When the broadband signal and the interference signal are expected to incident in the far field plane, how to suppress the influence of the interference signal and the noise signal is also an important problem in the constant beam width beamforming. In this paper, the realization of constant beam width beamforming algorithm and the zero notch formation in interference direction in beam graph are deeply studied. Firstly, under the idea of focusing transformation, the data on different frequency subbands of broadband signal are focused on a reference frequency by focusing transformation matrix, and the output matrix form of frequency domain data of each subband of broadband signal and the expression of focusing transformation matrix under RSS method are derived. then the beamformer with constant frequency beam width and good zero notch region is designed by MVDR beamforming method. Secondly, the constant beamwidth minimum sidelobe beamforming is realized by using SRV constraint, and then the optimal weight vector setting in broadband constant beamwidth beamforming is analyzed under the condition of satisfying the maximum output gain of the beam output and the zero notch suppression of the interference signal in the specified incoming direction of the desired signal, and the constant beamwidth MVDR minimum sidelobe beamforming under the SRV constraint to meet the design requirements is obtained, and a new algorithm is obtained. The simulation results show that the improved method has better output performance under the condition of small sampling number and high input SNR. Thirdly, the beamforming algorithm in the worst environment is studied, and the forming process of the beamforming algorithm is deduced in detail. The ellipsoid constraint set is introduced to realize the distortionless reception of the mismatched signal in any direction vector, and the optimization problem is simplified into a convex optimization problem. The optimal weight vector is obtained by the interior point method. Finally, the beamforming algorithm is applied to broadband constant beamwidth beamforming algorithm, and a constant beamwidth beamforming algorithm under guidance vector mismatch is proposed. The simulation results show that the algorithm has good robustness to the sampling autocorrelation matrix error and direction vector mismatch caused by small sampling samples, and can achieve constant beam width on bandwidth and form a large zero-notch depth in the wave side of the interference signal. Beamforming system has good output performance.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN911.7
【引证文献】
相关硕士学位论文 前1条
1 庞宇;语音分离技术的研究与实现[D];国防科学技术大学;2016年
，本文编号：2501186
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