Closed-form single source direction-of-arrival estimator using first-order relative harmonic coefficients

The relative harmonic coefficients (RHC), recently introduced as a multi-microphone spatial feature, demonstrates promising performance when applied to direction-of-arrival (DOA) estimation. All existing RHC-based DOA estimators suffer from a resolution limitation due to the inherent grid-based search. In contrast, this paper utilizes the first-order RHC to propose a closed-form DOA estimator by deriving a direction vector, which points towards to the desired source direction. Two objective metrics, namely localization accuracy and algorithm complexity, are adopted for the evaluation and comparison with existing RHC-based and intensity based localization approaches, in both simulated and real-life environments.