共查询到20条相似文献,搜索用时 171 毫秒
1.
首先介绍了宽带阵列信号模型,然后给出了一种基于空间重采样的新的宽带信号相干子空间处理算法。该算法将均匀线阵看成是连续线阵的离散采样,在各个频率点调整阵列空间采样率,将各频率分量的方向向量聚焦到参考频率上,聚焦后得到单一频率点的数据协方差矩阵,再应用窄带MUSIC算法进行DOA估计,无需预估计波达方向,因此可以避免角度预估计对测向性能的影响。仿真实验表明新算法的性能要优于其他典型算法(TCT,RSS和TLS算法)。文中还给出了分辨率与阵元个数、信噪比之间关系。 相似文献
2.
3.
针对宽带自适应空频处理的信噪比要求高、计算量大等问题,本文提出了一种基于均匀线阵的无需预延迟处理宽带空时处理结构的自适应和差波束形成与测角方法。方法利用和波束指向在多频点处的响应来建立多约束条件,以此获得基于线性约束最小方差的自适应和波束权向量,对多频点的空时二维向量修正和波束权向量得到差波束权向量,最后进行和差波束形成,对每个样本和差比幅单脉冲测角。本方法相比于常规的自适应单脉冲测角方法,可有效地处理宽带信号,不需要对每个频带信号进行检测,具有低信噪比条件下可测角、测角精确度高等特点,而且仿真分析验证了当存在主瓣干扰时,该方法仍然有效。 相似文献
4.
5.
宽带阵列信号是频率的函数,因此其阵列流型及协方差矩阵都随频率变化.本文基于宽带信号的频域模型,通过分析宽带阵列信号协方差矩阵的特征分解结构,证明了宽带阵列信号噪声子空间不随频率变化的特性,并根据这一特性,提出了基于频域模型的宽带子空间谱估计(SSEFD)方法.应用K.Buckley的BASS-ALE方法解决了该方法用于均匀线阵时存在的频率-方位模糊问题.计算机仿真结果验证了SSEFD方法的有效性,与H.Wang的CSS方法的统计性比较表明,新方法具有更高的估计精度. 相似文献
6.
7.
一种新的子阵结构及其自适应性能分析 总被引:2,自引:0,他引:2
在阵列信号处理中,大型阵由于系统结构复杂,成本较高,在实际应用中受到限制,而采用子阵结构则可以减少接收通道数,简化系统设计,降低成本。本文针对等幅均匀线阵提出了一种新的结构简单的子阵,并且通过打乱子阵排列的周期性以及保证各子阵输出噪声功率相等,该子阵的栅瓣效应几乎可以忽略且其自适应方向图保形良好。 相似文献
8.
9.
角度测量是现代雷达的基本功能之一,而和差单脉冲测角是雷达中常用的一种测角方式,该文研究了调频步进雷达的和差单脉冲测角问题.在雷达采用均匀线阵、发射频率步进线性调频相参脉冲串信号的情况下,文中推导了调频步进雷达和差单脉冲测角的角敏函数,它等于各相参脉冲对应的差波束方向图之和与和波束方向图之和的比值,借助于该角敏函数可以进... 相似文献
10.
11.
12.
13.
In the broadband signal processing, the array has different relative aperture for the different frequency bins, which results
in waveform distortion. Moreover, the greater the bandwidth is, the more serious the distortion becomes. It is valuable to
study the Frequency-invariant beam patterns (FIBPs) for receiving broadband signals without distortion. Based on the array
dimensions, this paper will summarize some new methods to design a broadband beamformer with an FIBP. There will be two categories:
One-dimensional arrays and Multi-dimensional arrays. For one-dimensional array, there are sampling rate method, minimax frequency
invariant beamforming, etc. For multi-dimensional array, there are Bessel function method, Bessel function and phase mode
method, and so on. Finally, we will discuss the pros and cons of every method. 相似文献
14.
传统的幅度约束波束形成器是一个非凸问题,需将原始模型化为线性规划进行间接求解。该文针对均匀线阵提出一种相位响应固定幅度响应约束(PFMC)的稳健波束形成方法。利用权矢量逆序列对应的传递函数与阵列响应函数只差一个相位因子这一性质,将阵列响应的相位设置为固定的线性相位,仅对阵列响应的实数幅度进行约束,从而得到一个凸的代价函数,最优权矢量可以利用内点法求出。同时考虑到协方差矩阵误差,利用最坏(WC)情况性能最优原理提出PFMC-WC算法改善PFMC的性能。与传统幅度约束波束形成器相比,减少了约束个数并省掉了恢复权矢量过程,从而降低了计算量。此外,由于相位响应得到保证,该文算法相对于传统算法具有更好的性能。仿真实验验证了该文算法的有效性。 相似文献
15.
一种宽带恒定束宽DBF技术实现方法 总被引:1,自引:0,他引:1
针对常规DBF方法不适用于宽带信号的问题提出一种宽带恒定束宽DBF方法.根据空间重采样理论将均匀线阵视为空间离散采样,利用内插定理得到各阵元在不同频点上的加权系数矩阵.利用维纳滤波理论设计宽带波束合成器拟合加权系数矩阵,实现宽带内波束指向一致,宽度相等.给出了理论分析依据及仿真结果,仿真结果表明了该方法具有计算复杂度低、稳健性强的优点. 相似文献
16.
Design of broadband beamformers robust against gain and phase errors in the microphone array characteristics 总被引:1,自引:0,他引:1
Fixed broadband beamformers using small-size microphone arrays are known to be highly sensitive to errors in the microphone array characteristics. The paper describes two design procedures for designing broadband beamformers with an arbitrary spatial directivity pattern, which are robust against gain and phase errors in the microphone array characteristics. The first design procedure optimizes the mean performance of the broadband beamformer and requires knowledge of the gain and the phase probability density functions, whereas the second design procedure optimizes the worst-case performance by using a minimax criterion. Simulations with a small-size microphone array show the performance improvement that can be obtained by using a robust broadband beamformer design procedure. 相似文献
17.
We add to the many results on sample covariance matrix (SCM) dependent array processors by (i) weakening the traditional assumption of Gaussian data and (ii) providing for a class of array processors additional performance measures that are of value in practice. The data matrix is assumed drawn from a class of multivariate elliptically contoured (MEC) distributions. The performance measures include the exact probability density functions (PDFs), confidence regions, and moments of the weight vector (matrix), beam response, and beamformer output of certain SCM-based (SCB) array processors. The array processors considered include the SCB: (i) maximum-likelihood (ML) signal vector estimator, (ii) linearly constrained minimum variance beamformer (LCMV), (iii) minimum variance distortionless response beamformer (MVDR), and (iv) generalized sidelobe canceller (GSC) implementation of the LCMV beamformer. It is shown that the exact joint PDFs for the weight vectors/matrices of the aforementioned SCB array processors are a linear transformation from a complex multivariate extension of the standardized t-distribution. The SCB beam responses are generalized t-distributed, and the PDFs of the SCB beamformer outputs are given by Kummer's function. All but the beamformer outputs are shown to be completely invariant statistics over the class of MECs considered 相似文献
18.
基于Frost 结构的Laguerre 宽带波束形成器可以获得比FIR 宽带波束形成器和IIR 宽带波束形成器更好的性能,但其需要单极点的最优求解过程,存在计算复杂度较高及收敛速度较慢等问题.该文提出一种基于广义旁瓣对消器(Generalized Sidelobe Canceller, GSC)的Laguerre 滤波器宽带波束形成算法.该算法首先建立基于GSC结构的Laguerre 宽带波束形成器模型,然后利用最小二乘方法给出一种低复杂度的极点求解方法,最后利用归一化最小均方根误差方法实现宽带波束形成.仿真实验及理论分析表明,该方法无需基于Frost 结构的Laguerre 宽带波束形成器单极点最优求解过程,在保证算法较高的输出信干噪比的同时,减少了计算复杂度,提高了收敛速度. 相似文献
19.
Robust forward backward based beamformer for a general-rank signal model with real-valued implementation 总被引:1,自引:0,他引:1
A robust forward backward (FB) beamformer for an incoherently scattered general-rank signal model with real-valued implementation is proposed based on the uniform linear array (ULA) structure by introducing a preprocessing transformation matrix. With the preprocessing, the computational complexity is reduced significantly due to a real-valued close-form solution for the optimum weight vector; furthermore, the proposed algorithm can achieve a higher output SINR (signal-to-interference-plus-noise ratio) and has lower sensitivity to the diagonal-loading parameters especially for low input SNR (signal-to-noise ratio) scenarios. 相似文献
20.
Huiping Duan Boon Poh Ng See C.M.S. Jun Fang 《Signal Processing, IEEE Transactions on》2008,56(6):2406-2416
The broadband interference suppression performance of the minimum redundancy array (MRA) used in the linearly constrained minimum variance (LCMV) beamformer is studied in this paper. The ideal continuous-time, infinite-length filter instead of the realistic finite-order digital filter is assumed in the array processor. The expressions of the power spectrum of the beamformer output in different scenarios are derived to compute the mean output power. Several original properties of the performance of the MRA compared with that of the uniform linear array (ULA) are obtained by mathematical proofs and numerical studies. 相似文献