Doubly constrained robust Capon beamformer
Doubly constrained robust Capon beamformer
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DOI：
10.1109/tsp.2004.831998
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发表时间：
2004-09-01
影响因子：
5.4
通讯作者：
Wang, ZS
中科院分区：
文献类型：
--
作者：
Li, J;Stoica, P;Wang, ZS
已知当阵列导向矢量精确已知时，标准Capon波束形成器（SCB）比标准的与数据无关的波束形成器具有更好的分辨率和更强的干扰抑制能力。然而，SCB的主要问题是在存在阵列导向矢量误差时缺乏稳健性。在本文中，我们将首先对一种范数约束的Capon波束形成（NCCB）方法进行全面分析，该方法对权向量使用范数约束以提高对阵列导向矢量误差和噪声的稳健性。我们对NCCB的分析是详尽的，并且比通常所了解的更清楚地阐明了范数约束的选择。我们还通过对阵列导向矢量施加双重约束，即恒定范数约束和球形不确定集约束，将通过协方差矩阵拟合得到的SCB自然扩展到导向矢量不确定的情况，我们将其称为双重约束的稳健Capon波束形成器（DCRCB）。NCCB和DCRCB都可以以与SCB相当的成本进行高效计算。还通过大量数值例子对NCCB、DCRCB以及其他几种自适应波束形成器进行了性能比较。
The standard Capon beamformer (SCB) is known to have better resolution and much better interference rejection capability than the standard data-independent beamformer when the array steering vector is accurately known. However, the major problem of the SCB is that it lacks robustness in the presence of array steering vector errors. In this paper, we will first provide a complete analysis of a norm constrained Capon beamforming (NCCB) approach, which uses a norm constraint on the weight vector to improve the robustness against array steering vector errors and noise. Our analysis of NCCB is thorough and sheds more light on the choice of the norm constraint than what was commonly known. We also provide a natural extension of the SCB, which has been obtained via covariance matrix fitting, to the case of uncertain steering vectors by enforcing a double constraint on the array steering vector, viz. a constant norm constraint and a spherical uncertainty set constraint, which we refer to as the doubly constrained robust Capon beamformer (DCRCB). NCCB and DCRCB can both be efficiently computed at a comparable cost with that of the SCB. Performance comparisons of NCCB, DCRCB, and several other adaptive beamformers via a number of numerical examples are also presented.