Wideband direction-of-arrival estimation using spatially interpolated wideband beamformers

We present a new method for wideband direction-of-arrival (DOA) estimation, based on a spatially interpolated wideband beamformer (SIWB). The SIWB is designed to have a frequency-invariant beam-response, prescribed main beamwidth and prescribed sidelobe level within a wide signal bandwidth. For wideband DOA estimation, the SIWBs can be used as spatial preprocessors transforming the wideband signals at the outputs of an antenna array (element-space) into the beam-space signals prior to applying narrowband DOA estimation. The new SIWB-based method enhances the resolution of spectral estimation and reduces the root-mean-square error of DOA estimation without increasing the number of array elements. Furthermore, the proposed method is applicable for DOA estimation of coherent sources without preliminary DOA estimates. The performance of the proposed method in comparison with conventional methods is illustrated in simulation results.