Lin Bin, Hu Guoping, Zhou Hao, Zheng Guimei, Song Yuwei
Air and Missile Defense College, Air Force Engineering University, Xi'an 710051, China.
Graduate College, Air Force Engineering University, Xi'an 710051, China.
Sensors (Basel). 2022 Jun 27;22(13):4853. doi: 10.3390/s22134853.
Due to the discontinuity of ocean waves and mountains, there are often multipath propagation effects and obvious pulse characteristics in low-altitude detection. If the conventional direction of arrival (DOA) estimation method is directly used for direction finding, it will lead to a large error. In view of serious misalignment in the DOA estimation of multipath signals under the background of impulse noise, a DOA estimation method based on spatial difference and a modified projection subspace algorithm is proposed in this paper. Firstly, the covariance matrix of the received data vector is used for spatial difference to eliminate the multipath effects of low-altitude targets. Secondly, the modified projection matrix is constructed using the signal source estimated with the least squares criterion and then used for modifying the covariance matrix, thus eliminating the cross-covariance matrices that affect the estimation accuracy. Finally, the modified covariance matrix is used for the DOA estimation of targets. Simulations show that the proposed algorithm achieves a higher accuracy in the DOA estimation of low-altitude targets than conventional algorithms under two common impulse noise models, without requiring prior knowledge of impulse noise.
由于海浪和山脉的不连续性，低空探测中经常存在多径传播效应和明显的脉冲特征。如果直接使用传统的到达方向（DOA）估计方法进行测向，会导致较大误差。针对脉冲噪声背景下多径信号DOA估计严重失准的问题，本文提出一种基于空间差分和改进投影子空间算法的DOA估计方法。首先，利用接收数据向量的协方差矩阵进行空间差分，以消除低空目标的多径效应。其次，使用基于最小二乘准则估计的信号源构建改进的投影矩阵，然后用于修正协方差矩阵，从而消除影响估计精度的互协方差矩阵。最后，将修正后的协方差矩阵用于目标的DOA估计。仿真结果表明，在两种常见的脉冲噪声模型下，该算法在低空目标DOA估计中比传统算法具有更高的精度，且无需脉冲噪声的先验知识。
