针对二维混合多输入多输出（MIMO）相控阵雷达发射阵列子阵分割带来的自由度损失问题，提出一种基于二维嵌套阵列的二维混合MIMO相控阵雷达接收阵列设计新方法。首先，给出一种由稀疏阵列和密集阵列构成的嵌套阵接收阵列的二维混合MIMO相控阵雷达信号模型；其次，通过对接收信号的协方差矩阵进行Khatri-Rao乘积处理，得到阵元位置差的差异阵列，形成接收阵元数目的虚拟扩展；最后，通过空间平滑处理进行波达方向估计。仿真实验表明，与传统二维混合MIMO相控阵雷达相比，所提方法在不增加实际阵元数目的情况下可以有效扩展虚拟阵元数目，提高雷达阵列自由度，进而提高二维混合MIMO相控阵雷达波达方向估计精度。
Division of the transmit array of the two-dimensional hybrid Multiple-Input Multiple-Output (MIMO) phased-array radar will cause the problem of loss of Degrees of Freedom (DOF). This paper proposes a method for the design of the receiving array of the two-dimensional hybrid MIMO phased-array radar based on the two-dimensional nested array. A signal model for the radar is given, which consists of the sparse array and the dense array. Then by constructing the Khatri-Rao product of the covariance matrix of the receiving signal, virtual extension of array elements is achieved by forming the difference co-array. Direction of arrival estimation is conducted based on spatial smoothing. Simulation results demonstrate that the proposed method can improve degrees of freedom without increase of elements, and then improve DOF estimation accuracy of the two-dimensional hybrid MIMO phased-array radar.
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