一种协方差矩阵实部消除的目标方位估计方法

Real-part elimination of covariance matrix method for direction-of-arrival estimation

针对实际复杂海洋环境条件下的目标方位估计性能变差的问题,提出了一种基于实部消除技术的目标方位估计方法。首先将噪声场分解为对称噪声部分和非对称噪声部分。然后利用协方差矩阵虚部,采用延迟求和波束形成方法获得目标方位估计,但是同时产生了对称的虚假目标。最后基于功率估计重构协方差矩阵实部,并与虚部组成新的协方差矩阵,利用新的协方差矩阵做目标方位估计,消除了虚假目标的影响。理论分析与湖试数据处理结果表明:该方法明显抑制了噪声,提高了目标方位估计的性能。实部消除技术易于实现,有较强的工程应用价值。

Performance of direction-of-arrival （DOA） estimation decreases obviously in the actual ocean ambient noise. To tackle this problem, the real-part elimination of covariance matrix method is proposed. Firstly, the noise field is decomposed into symmetrical noise filed and asymmetrical noise field. Secondly, the real part of covariance matrix is eliminated so as to suppress the symmetrical noise, and then the DOAs are estimated using imaginary part and delay-and-sum beamforming method. Meanwhile, it produces false targets. Finally, a new covariance matrix, which is composed of the imaginary part and the reconstruction of the real part, is applied to estimate DOAs so as to eliminate the false targets. Both the theoretical analysis and experimental results show that this method improves performance of direction-of-arrival estimation by suppressing noise.