DOA estimation of mixed near-field and far-field sources using spherical array

In practical applications, the observations collected by a spherical array may be mixed far-field and near-field signals. A new approach which exploits the recursive relationship of spherical harmonics is proposed to estimate the direcitons of arrival (DOAs) of multiple mixed sources. The algorithm is independent of the far-field or near-field assumption in the spherical harminics domain. It avoids high dimensional search and provides accurate estimation. Simulation results demonstrate better estimation performance.