基于压缩感知的波束域反卷积波束形成算法
Beam-domain deconvolution beamforming algorithm enhanced by compressive sensing
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摘要: 反卷积波束形成可有效抑制旁瓣、提高目标探测的方位分辨力, 传统反卷积波束形成算法大多要求阵列指向性函数满足移不变性, 只适用于直线阵、圆阵等特定阵列; 传统方法通常对波束强度进行处理, 不适用于处理相干信号。为此, 提出了一种基于压缩感知的适用于任意阵列的波束域反卷积波束形成方法, 该方法首先通过常规波束形成获取若干复数域波束输出, 再将稀疏贝叶斯学习(SBL)重构算法应用于波束域模型进行复数域波束输出的反卷积, 从而实现目标检测和波达方向估计。所提方法通过控制常规波束形成输出波束数, 可有效降低算法的计算复杂度, 且在处理相干信号时同样适用, 方位分辨性能优于常规反卷积算法。仿真与海试数据处理结果表明, 所提算法的方位分辨性能与传统阵元域SBL波束形成算法相当, 且均优于常规波束形成和最小方差无失真响应方法; 在应用于短密阵等阵列条件下, 所涉及常规波束形成波束数明显小于阵元数时, 所提算法的计算复杂度显著低于传统阵元域SBL波束形成算法。Abstract: Deconvolution beamforming can effectively suppress sidelobes and improve the azimuth resolution of multiple targets. However, traditional deconvolution beamforming methods mostly require the beam pattern to be shift-invariant, so they are only suitable for specific arrays such as linear arrays and circular arrays. Traditional deconvolution beamforming methods usually focus on beamforming intensity, which proves inadequate for handling coherent signals. To address this limitation, a deconvolution beamforming method for arbitrary arrays in beam domain is proposed, which is developed within the framework of compressive sensing. This method first uses conventional beamforming to obtain several complex output beams, and then applies the sparse Bayesian learning (SBL) algorithm to achieve deconvolution of complex output beams. This deconvolution process enhances the accuracy of direction of arrival (DOA) estimation for true targets. The proposed method effectively reduces computational complexity by optimizing the number of output beams generated during conventional beamforming. It is equally applicable to both uncoherent and coherent signals, outperforming conventional deconvolution beamforming methods. The simulation and experimental results demonstrate that the proposed method has azimuth resolution performance comparable to the traditional SBL beamforming in element domain, while outperforming conventional beamforming and minimum variance distortionless response (MVDR) method. When applied to short dense arrays, the proposed method achieves significantly lower computational complexity compared to traditional SBL in element domain, particularly when the number of output beams from conventional beamforming is much smaller than the number of array elements.