基于协方差矩阵重构和导向矢量估计的稳健自适应波束形成

实际应用中, 当假定的与真实的期望信号导向矢量之间存在一定误差时, 波束形成器的性能会急剧下降, 特别是当期望信号功率很强的时候.为解决这个问题, 提出了一种新的算法.当信源数小于阵元数时, 干扰加噪声协方差矩阵具有稀疏性.新方法首先利用该特性重构干扰加噪声协方差矩阵并由此得到与干扰导向矢量正交的子空间, 使接收的数据通过该子空间得到只含有期望信号和噪声的混合信号, 然后，对该混合信号基于最大化输出功率原理估计期望信号导向矢量, 最后，把得到的导向矢量和正交子空间来构造阵列加权值.仿真结果表明:该算法分别在假定的期望信号导向矢量存在误差、期望信号很强和低快拍数时仍然具有良好的性能.

Robust adaptive beamforming based on reconstruction of the covariance matrix and the estimation of steering vector

In the practical application, the error between the assumed steering vector of the desired signal and the real one causes the sharp degrading of the beamforming performance, especially when the desired signal power is strong. To solve this problem, a novel robust algorithm is proposed. The interference-plus-noise covariance matrix is sparse when the number of the signal source is less than the array element number. At first, by using this sparse property, the interference-plus-noise covariance matrix can be reconstructed, from which a subspace orthogonal to the steering vectors of interference signals can be obtained. Then, a mixed signal only containing the desired signal and the noise can be gained by mapping the received data through to this orthogonal subspace. The real steering vector of the desired signal can be estimated based on maximizing the out power of the mixed signal. The final beamforming weight can be constructed by using the orthogonal subspace and the real steering vector of the desired signal. Simulation results demonstrate the efficiency of the proposed algorithm in the case of the mismatch of the steering vector of the desired signal, the strong desired signal and the low snapshot number.