Wideband Direction-of-Arrival Estimation With Arbitrary Array via Coherent Annihilating

In this paper, a new wideband DOA estimation method for arbitrary array application is proposed. The arbitrary array manifold is approximately decomposed under the concept of manifold separation technique (MST) and a linear combination of the equal interval sampling complex exponentials (EISCE) can be synthesized. Since the EISCEs at all frequencies contain the same DOA information, they can be annihilated by the same spatial annihilating filter. So, the coherent annihilating scheme is proposed, and all narrowband components are coherently combined to construct an optimization problem under the structural total least squares framework. During the optimization problem construction, the general solution method is proposed to enable the model approximation error in MST to be reduced to a negligible level. Finally, the optimization problem is solved through the multiple measurement vectors structural total least norm (MMV-STLN) approach and the DOAs are estimated from the reconstructed spatial annihilating filter. The new method is free of frequency focusing and is capable of handling both incoherent and coherent signals. The simulation results verify that the proposed method surpasses the existing methods largely in resolution and estimation performance under the low SNR, snapshot deficient, and closely spaced sources scenarios.