Localizing mixed far- and near-field sources using beamforming deconvolution techniques

A beam deconvolution technique for the location of the mixed far- and near-field sources is presented in this paper. The generalized two-dimensional convolution formalism inherent in the conventional beamforming (CBF) spatial spectrum yielded by the linear array observations for noncoherent mixed signals is derived. The Richardson-Lucy algorithm is exploited to focus beam power and obtain accurate spatial parameters of the near-field sources. The far-field components are extracted by mapping the mixed-source covariance matrix to the near-field manifold’s orthogonal complement space. The intrinsic one-dimensional convolution relationship is revealed. Hence, the angular domain beamforming deconvolution is used to estimate the far-field signals’ incident angles. The simulation results show that the proposed method improves the spatial resolution of the CBF spectrum and can separate the mixed sources after isolating the near-field components by projection mapping. Besides, a background noise level suppression of 10 dB for the far-field sources is achieved by comparing it with the existing schemes.