一种非平滑相干干扰鲁棒的自适应波束形成器

A robust adaptive beamformer with non-smoothing coherent interference

针对文献报道的鲁棒自适应波束形成(robust adaptive beamforming,RAB)算法,分析了在存在相干干扰时其性能严重下降甚至失效的原因:通过将接收信号协方差矩阵分解为阵列流形矩阵左和共轭右乘一个矩阵P的描述形式,在存在相干干扰时,P为非对角阵,其非对角元素表征了信号与干扰间的互相关,该成分造成了RAB算法的失效;另表明:快拍数有限可视为特殊的相干干扰情况。为此,提出了一种构建P为对角阵的协方差矩阵拟合方法;并据拟合的协方差矩阵,给出了对非平滑相干干扰RAB方法。仿真验证了分析的有效性,所提方法在相干干扰时仍能实现非相干干扰时的性能,且收敛速度优于报道方法。

The robust adaptive beamforming(RAB)algorithms reported in the literature are analyzed,to explain the serious performance degradation or even completely invalid in the presence of coherent interference.When the covariance matrix of the received data is decomposed into the description form of the array manifold matrix left and conjugate right multiplied by a matrix P.P is a non-diagonal matrix when the received data are interfered by the coherent signal sources,and the off-diagonal elements in the matrix P represent the coherences between the signal and interference sources as well as among interference ones,which are the main reasons for the failure of RAB algorithm reported in the literature.It is shown further that the insufficient number of snapshots can be regarded as a special case of coherent interference.In order to deal with these situations,a covariance matrix fitting method is proposed by constructing P as a diagonal matrix.Based on the fitted covariance matrix,an RAB method for non-smooth coherent interference is presented.The simulation results verify the effectiveness of the analytical ones.Meanwhile,they also show that the proposed method can still achieve the performances of the non-coherent interference RAB algorithms in the case of coherent interference,and has a faster convergence rate than the methods reported in the literature.