Faculty of Information Science and Engineering, Ocean University of China, Qingdao, China.
PLoS One. 2023 Oct 19;18(10):e0293012. doi: 10.1371/journal.pone.0293012. eCollection 2023.
Recently, many robust adaptive beamforming (RAB) algorithms have been proposed to improve beamforming performance when model mismatches occur. For a uniform linear array, a larger aperture array can obtain higher array gain for beamforming when the inter-sensor spacing is fixed. However, only the small aperture array can be used in the equipment limited by platform installation space, significantly weakening beamforming output performance. This paper proposes two beamforming methods for improving beamforming output in small aperture sensor arrays. The first method employs an integration algorithm that combines angular sector and gradient vector search to reconstruct the interference covariance matrix (ICM). Then, the interference-plus-noise covariance matrix (INCM) is reconstructed combined with the estimated noise power. The INCM and ICM are used to optimize the desired signal steering vector (SV) by solving a quadratically constrained quadratic programming (QCQP) problem. The second method proposes a beamforming algorithm based on a virtual extended array to increase the degree of freedom of the beamformer. First, the virtual conjugated array element is designed based on the structural characteristics of a uniform linear array, and received data at the virtual array element are obtained using a linear prediction method. Then, the extended INCM is reconstructed, and the desired signal SV is optimized using an algorithm similar to the actual array. The simulation results demonstrate the effectiveness of the proposed methods under different conditions.
最近，提出了许多强大的自适应波束形成（RAB）算法，以在模型失配时改善波束形成性能。对于均匀线性阵列，当传感器间隔固定时，较大的孔径阵列可以在波束形成时获得更高的阵列增益。然而，只有在平台安装空间有限的设备中才能使用小孔径阵列，这显著削弱了波束形成输出性能。本文提出了两种用于提高小孔径传感器阵列波束形成输出的方法。第一种方法采用了一种集成算法，该算法结合了角度扇区和梯度向量搜索来重建干扰协方差矩阵（ICM）。然后，结合估计的噪声功率来重建干扰加噪声协方差矩阵（INCM）。使用求解二次约束二次规划（QCQP）问题来优化期望信号导向矢量（SV）。第二种方法提出了一种基于虚拟扩展阵列的波束形成算法，以增加波束形成器的自由度。首先，根据均匀线性阵列的结构特点设计虚拟共轭阵列元素，并使用线性预测方法获得虚拟阵列元素上的接收数据。然后，重建扩展的 INCM，并使用类似于实际阵列的算法优化期望信号 SV。在不同的条件下，仿真结果证明了所提出方法的有效性。
