Augmented Matrix Construction Based DOA Estimation of Coherent Underwater Acoustic Signals.

Direction of arrival (DOA) estimation is critical in various fields, including wireless communications, radar, sonar, and electronic reconnaissance. Traditional DOA algorithms like minimum variance distortion-less response (MVDR) and multiple signal classification (MUSIC) are effective for incoherent sources. However, the presence of coherent signals due to underwater multipath propagation and human interference poses a challenge for traditional incoherent signal estimation algorithms. In this paper, we propose an augmented matrix construction based on DOA estimation of coherent signals, which firstly completes the conjugate rearrangement of the original received data, then obtains the autocorrelation matrix of the rearranged data, and obtains the cross-correlation matrix with the original received data. Finally, the augmentation matrix is constructed based on the covariance matrix of the original received signal, the conjugate rearrangement signal's autocorrelation matrix, and the two signals' intercorrelation matrix. Hence, this approach makes full use of the information of the echo signal, so it has higher resolution and estimation accuracy. Simulation analysis is conducted to verify the effectiveness and accuracy of our proposed algorithm. The results demonstrate that the algorithm outperforms traditional DOA estimation algorithms and provides robust performance in the presence of coherent signals.