Joint DOA and fundamental frequency estimation based on relaxed iterative adaptive approach and optimal filtering

In this work, the problem of joint direction-of-arrival and fundamental frequency estimation for multi-channel harmonic sinusoidal signals is addressed. Different from the conventional optimal filtering method, we estimate the covariance matrix with the 2-D iterative adaptive approach, which is based on a single snapshot. In addition, to improve the estimation accuracy for the off-grid sources, a relaxation technique is utilized. Then, joint estimation is conducted on this covariance matrix estimate with the optimal filtering method. As a result, the relaxed iterative adaptive approach - optimal filtering method is devised. Statistical evaluation with synthetic signals shows the accurate performance of the proposed method compared with the Cramér-Rao lower bound.