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Researchers have recently shown an increased interest in estimating the direction-of-arrival (DOA) of wideband noncircular sources, but existing studies have been restricted to subspace-based methods. An off-grid sparse recovery-based algorithm is proposed in this paper to improve the accuracy of existing algorithms in low signal-to-noise ratio situations. The covariance and pseudo covariance matrices can be jointly represented subject to block sparsity constraints by taking advantage of the joint sparsity between signal components and bias. Furthermore, the estimation problem is transformed into a single measurement vector problem utilizing the focused operation, resulting in a significant reduction in computational complexity. The proposed algorithm's error threshold and the Cramer–Rao bound for wideband noncircular DOA estimation are deduced in detail. The proposed algorithm's effectiveness and feasibility are demonstrated by simulation results. 相似文献
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为了获取较高的宽带信号的DOA(direction-of-arrival)估计精度,提出了基于改进的广义回归神经网络(IGRNN,improved generalized regression neural network)和主成分分析(PCA,principalcomponent analysis)的宽带DOA估计算法。选用PCA方法对训练样本进行降维,以降低神经网络的复杂度;利用粒子群算法优化GRNN的参数;根据选取不同的聚焦角度确定粗估计、精估计的训练模型,通过粗估计得出目标的大致方位后,利用精估计模型得出最终的估计结果,避免了聚焦角度对估计精度的影响。仿真结果表明,本文提出的算法具有较好的估计精度和较高的工作效率。 相似文献
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本文针对均匀线性阵列,在正交投影子空间(TOPS)算法的基础上,提出了一种新的宽带非相关和相干信号的DOA估计算法。首先,利用TOPS算法直接估计出宽带非相关信号的DOA;其次,在各个频率点,使用空间差分技术消除非相关信号和噪声的分量,并构造新矩阵;最后,对新矩阵进行空间平滑操作,再利用TOPS算法估计出宽带相干信号的DOA。由于分开估计宽带非相关信号和相干信号的DOA,算法适用于信号个数多于阵元个数的场合。计算机仿真结果证明了算法的有效性。 相似文献
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提出了一种相干宽带线性调频(LFM)信号的波达方向(DOA)估计新方法。该方法利用LFM信号在分数阶Fourier域上的解线调特性,构造出新的解线调域阵列数据模型,然后结合传统的矩阵重构解相干以及MUSIC算法实现相干LFM信号的DOA估计。若同时存在多组相干LFM信号入射,则首先在不同的能量聚集域上将各信号组分离,然后逐一进行各组内相干信号的DOA估计。该方法充分地挖掘了观测信号所包含的时频信息,增加了可检测的DOA数目,提高了分辨性能和抗噪声性能。此外,该方法无冗余阵元与孔径损失,且适用于任意流型阵列。仿真结果显示,在DOA估计的均方根误差(RMSE)相同时,与传统方法相比,本方法可获得8dB左右的信噪比增益。 相似文献
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吴仁彪 《电子科学学刊(英文版)》1993,10(3):249-254
A novel universal preprocessing method is proposed to estimate angles of arrival,which is applicable to one-or two-dimensional high resolution processing based on arbitrarycenter-symmetric arrays (such as uniform linear arrays, equal-spaced rectangular planar arraysand symmetric circular arrays). By mapping the complex signal space into the real one, the newmethod can effectively reduce the computation needed by the signal subspace direction findingtechniques without any performance degradation. In addition, the new preprocessing scheme itselfcan decorrelate the coherent signals received on the array. For regular array geometry such asuniform linear arrays and equal-spaced rectangular planar arrays, the popular spatial smoothingpreprocessing technique can be combined with the novel approach to improve the decorrelatingability. Simulation results confirm the above conclusions. 相似文献
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A CLOSED-FORM WIDEBAND DIRECTION-OF-ARRIVAL ESTIMATION WITH CHIRPLET-BASED ADAPTIVE SIGNAL DECOMPOSITION ALGORITHM 总被引:1,自引:0,他引:1
Feng Aigang Yin Qinye Wu Xiaojun Zhao Zheng 《电子科学学刊(英文版)》2003,20(1):1-7
The Direction-Of-Arrival (DOA) estimation with Coherent Signal Subspace (CSS)is not easy to cxtend from narrowband to wideband case.Time-frequency analysis is a powerfultechnique to deal with time-variant or non-stationary signal. Its combination with CSS exploresa new field in signal processing, especially the wideband DOA estimation. The chirp function isone of the most fundamental functions in nature. Many nature events can be modeled as chirpletfunction, such as radar system or scismic exploring.Hence,the chirplet-based signal decomposi- 相似文献
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在进行波达方向估计时,往往要对信号个数进行判断,传统的宽带信号个数检测方法需要在每个频点上进行多次采样,否则无法正确完成测向.针对此问题,提出了一种基于Bootstrap准则实现的宽带信号个数检测新方法.将宽带信号划分为若干个互不重叠的子带部分,之后对每个子带信号进行特征分解,利用特征值对相应的特征向量进行加权,再通过Bootstrap准则构造新的信号重采样矩阵,用聚类的方法判断出该子带上的信号个数,最后将各个子带上的结果进行综合判断出宽带信号个数.所提方法回避了聚焦的过程,且在非高斯噪声背景下也有较高的估计成功概率,尤其是在小快拍数下有着较好的估计性能,仿真结果证明了该方法的性能. 相似文献
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A new method of measurement of distortion product otoacoustic emission (DPOAE) signal level based on a recently introduced nonlinear adaptive method of extraction of nonstationary sinusoids is presented. Essentially, three units of such an algorithm are employed to extract and measure the two stimuli and the DPOAE signal. Each unit has the capability of locking on a specified sinusoidal component of the input signal and tracking its variations over time. Performance of the proposed method is demonstrated with the aid of computer simulations and is verified in laboratory using recorded clinical data. Comparison is made between the proposed technique and existing methods. The proposed method features structural simplicity which renders it particularly attractive for implementation on both software and hardware platforms. It offers a high degree of immunity with regard to background noise and parameter variations. Compared to conventional methods, the proposed method offers a shorter measurement time which is of significant value in clinical examinations. 相似文献
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Yasoub Eghbali Mahmoud Ferdosizade Naeiny 《International Journal of Communication Systems》2020,33(14)
In this paper, an off‐grid direction of arrival (DoA) estimation method is proposed for wideband signals. This method is based on the sparse representation (SR) of the array covariance matrix. Similar to the time domain DoA estimation methods, the correlation function of the sources was assumed to be the same and known. A new measurement vector is obtained using the lower‐left triangular elements of the covariance matrix. The DoAs are estimated by quantizing the entire range of continuous angle space into discrete grid points. However, the exact DoAs may be located between two grid points; therefore, this estimation has errors. The accuracy of DoA estimation is improved by the minimization of the difference between the new measurement vector and its estimated values. Simulation results revealed that the proposed method can enhance the DoA estimation accuracy of wideband signals. 相似文献
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In the application of direction-of-arrival (DOA) estimation based on sensor array, bearing-discretization has been a major technique for the sparsity-based methods in the past decade. However, discretization leads to the modeling error of sparse representation, which usually deteriorates the accuracy of DOA estimation. In this paper, a sparse continuous-field and super-resolution method (SCSM) is proposed to overcome the discretization issue. SCSM estimates DOA in the continuous bearing-space by solving a minimization problem, which combines the measurement covariance fitting criterion with the source-sparsity constraint characterized by minimizing an atomic norm. This minimization problem has a unique solution. After obtained the solution uniquely, Prony’s method is utilized to estimate the DOA of sources. Therefore, SCSM has the capability to acquire a sparse and accurate estimation of DOA. In addition, it has some other advantages, including excellent super-resolution capability, no requirement of source number, applicability to arbitrary number of snapshots. Numerical results demonstrate the superior performance of the presented method. 相似文献
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Bo Lin Jiying Liu Meihua Xie Jubo Zhu Fengxia Yan 《Multidimensional Systems and Signal Processing》2017,28(1):183-205
A new method is proposed to estimate the direction-of-arrival (DOA) based on uniform linear array sampling and named as sparsity and temporal correlation exploiting (SaTC-E). By exploiting the structure information of source signals, including spatial sparsity and temporal correlation of sources, SaTC-E accomplishes DOA estimation with superior performance via block sparse bayesian learning methodology and grid refined strategy. SaTC-E is applicable into time-varying manifold scenario, such as wideband sources, time-varying array, provided that the array manifold matrix is determinable. It has improved performance with some other merits, including superior resolution, requirement for a few snapshots, no knowledge of source number, and applicability to spatially and temporally corrected sources. Real data tests and numerical simulations are carried out to demonstrate the advantages of SaTC-E. 相似文献
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Computationally efficient subspace-based method for direction-of-arrival estimation without eigendecomposition 总被引:3,自引:0,他引:3
A computationally simple direction-of-arrival (DOA) estimation method with good statistical performance is attractive in many practical applications of array processing. In this paper, we propose a new computationally efficient subspace-based method without eigendecomposition (SUMWE) for the coherent narrowband signals impinging on a uniform linear array (ULA) by exploiting the array geometry and its shift invariance property. The coherency of incident signals is decorrelated through subarray averaging, and the space is obtained through a linear operation of a matrix formed from the cross-correlations between some sensor data, where the effect of additive noise is eliminated. Consequently, the DOAs can be estimated without performing eigendecomposition, and there is no need to evaluate all correlations of the array data. Furthermore, the SUMWE is also suitable for the case of partly coherent or incoherent signals, and it can be extended to the spatially correlated noise by choosing appropriate subarrays. The statistical analysis of the SUMWE is studied, and the asymptotic mean-squared-error (MSE) expression of the estimation error is derived. The performance of the SUMWE is demonstrated, and the theoretical analysis is substantiated through numerical examples. It is shown that the SUMWE is superior in resolving closely spaced coherent signals with a small number of snapshots and at low signal-to-noise ratio (SNR) and offers good estimation performance for both uncorrelated and correlated incident signals. 相似文献
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提出了一种新的正弦信号频率和初相估计方法——频谱遍历法.该方法通过改变理想正弦信号频谱峰值实现对采样信号频谱峰值的遍历.分析了噪声对信号频谱幅度的影响,并以此给出了谱线遍历范围的选取准则.先估计频率,采用移频操作达到了良好的频域稳定性;再估计相位,避免了相位测量模糊的问题.在信噪比为6dB、采样点数为1024的情况下,频率估计均方根误差约为DFT频率分辨率的0.8%,初相估计均方根误差约为1.5°.Monte Carlo仿真表明,在达到一定信噪比或采样长度时,该方法的频率估计精度可突破CR下限,初相估计精度基本达到CR下限. 相似文献
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该文提出了采用实测的信道自相关系数作为权重的信道估计处理方法,并给出其误差性能的数学表达式,同时给出了经典的滑动平均信道估计方法的误差性能的数学表达式。理论分析及仿真结果表明所提的方法能自动适应移动信道的时变模型及衰落速率,具有有效地抑制噪声的优点;同时克服了滑动平均估计方法的估计长度对估计准确性影响较大的缺点,在移动速度固定及移动速度变化很大的环境下都具有稳定的误差性能;尤其在移动速度变化很大的环境下具有比滑动平均估计方法更低的估计方差,大大提高了RAKE接收机的性能。 相似文献