Wang Baoping, Zheng Junhao
National Key Laboratory of Science and Technology on UAV, Northwestern Polytechnical University, Xi'an 710072, China.
School of Electronics and Information, Northwestern Polytechnical University, Xi'an 710072, China.
Sensors (Basel). 2020 Feb 12;20(4):994. doi: 10.3390/s20040994.
Recently developed super nested array families have drawn much attention owing to their merits on keeping the benefits of the standard nested arrays while further mitigating coupling in dense subarray portions. In this communication, a new mutual coupling model for nested arrays is constructed. Analyzing the structure of the newly formed mutual coupling matrix, a transformation of the distorted steering vector to separate angular information from the mutual coupling coefficients is revealed. By this property, direction of arrival (DOA) estimates can be determined via a grid search for the minimum of a determinant function of DOA, which is induced by the rank reduction property. We also extend the robust DOA estimation method to accommodate the unknown mutual coupling and gain-phase mismatches in the nested array. Compared with the schemes of super nested array families on reducing the mutual coupling effects, the solutions presented in this paper has two advantages: (a) It is applicable to the standard nested arrays without rearranging the configuration to increase the inter-element spacing, alleviating the cross talk in dense uniform linear arrays (ULAs) as well as gain-phase errors in sparse ULA parts; (b) Perturbations in nested arrays are estimated in colored noise, which is significant but rarely discussed before. Simulations results corroborate the superiority of the proposed methods using fourth-order cumulants.
最近开发的超嵌套阵列族因其在保留标准嵌套阵列优点的同时进一步减轻密集子阵列部分耦合方面的优势而备受关注。在本通信中，构建了一种用于嵌套阵列的新互耦模型。通过分析新形成的互耦矩阵的结构，揭示了一种将失真的导向矢量进行变换以从互耦系数中分离角度信息的方法。基于此特性，可以通过对由秩降低特性引起的波达方向（DOA）行列式函数的最小值进行网格搜索来确定DOA估计值。我们还扩展了鲁棒DOA估计方法，以适应嵌套阵列中未知的互耦和增益相位失配。与超嵌套阵列族在降低互耦效应方面的方案相比，本文提出的解决方案具有两个优点：（a）它适用于标准嵌套阵列，无需重新排列配置以增加阵元间距，减轻了密集均匀线性阵列（ULA）中的串扰以及稀疏ULA部分中的增益相位误差；（b）在有色噪声中估计嵌套阵列中的扰动，这一点很重要但以前很少被讨论。仿真结果证实了使用四阶累积量的所提方法的优越性。
