Direction-of-arrival estimation in half-space from single sample array snapshot

Most existing direction-of-arrival (DOA) estimation algorithms are intended for single-frequency use. However, the majority of real sound fields are wideband, and the application of these techniques then becomes computationally expensive. In this paper, a fast DOA estimation method for use with wideband sound fields is constructed from only a single observation of the array signal based on the properties of a space of spherically band-limited functions. The proposed method can be applied to any element arrangement and spatial dimensions, and the computational load is only dependent on the number of microphones in the array. However, because this method does not use time information, forward-backward identification of the arriving waves is not possible. Therefore, the proposed DOA estimation method is limited to a half-space. Numerical simulations of multiple sound waves arriving from a half-space show that the proposed method offers good processing performance when applied to pulse-like broadband sound fields. The results also indicate that the method is capable of tracking DOAs in real time, even when these DOAs vary rapidly.