当前多输入多输出(MIMO)雷达的波达方向(DOA)估计算法都是在各发射阵元的发射信号间完全正交(POWS)的条件下提出的。当发射信号正交性无法满足时,DOA算法的估计性能会出现明显衰减。针对发射信号不完全正交(NonPOWS)时的DOA估计问题,文中提出了基于修正矩阵转换的MIMO阵列降维Root-MUSIC算法。利用发射信号的相关矩阵构造修正转换矩阵,对接收信号进行修正,保证修正后的接收信号模型与理想的发射信号完全正交条件下的虚拟阵列信号模型相同。为了降低运算复杂度,利用降维转换矩阵将数据矩阵变换到低维数据空间。在对由于发射信号非正交性和转换矩阵引入的色噪声进行预白化处理后,利用Root-MUSIC算法对预白化后的接收数据进行DOA估计。仿真试验表明:在非正交发射信号的情况下,与现有算法相比,文中算法具有更好的角度估计性能和更低的运算复杂度。

In direction of arrival (DOA) estimation for colocated multiple-input multiple-output (MIMO) radar, many existing literatures have been proposed based on a hypothesis that the transmit signals are perfectly orthogonal waveforms (POWS). However, in practice, the orthogonality of transmit waveforms are hardly guaranteed which may degrade the estimation accuracy. A novel DOA estimation method called Root-MUSIC algorithm for colocated MIMO radar with non-perfectly orthogonal waveforms ( NonPOWS) based on modification matrix transformation is proposed. The modification matrix is constructed with correlation matrix of transmit waveforms to modify the received data, so as to ensure the consistency of the steering vector of the virtual extended array under POWS with the modified receiving signal model. In order to reduce the computational complexity, signal dimensional reduction processing is done with dimensional reduction matrix. After prewhitening the colored noise introduced by the nonorthogonality of transmit waveforms and matrix transformation, DOA estimation for prewhitened received data is done via Root-MUSIC algorithm. The simulation results show that the proposed method provides better estimation accuracy and lower computational complexity than existing algorithms under nonorthorgonal transmit waveforms.

TN957.51