Near-field scattering centers estimation using a far-field 3-D ESPRIT type method

A method is presented for estimating the three-dimensional (3-D) scattering centers of an object under spherical wave illumination. A novel approximation of the distance from the antenna to each scattering center is first formulated, which provides an approach for compensating for the spherical wavefront curvature. Additionally, the approximation transforms the near-field problem into virtual far-field problem. A far-field 3-D ESPRIT type algorithm is also presented and applied to estimating the virtual far-field scattering centers. Finally, the near-field scattering centers are obtained by using the compensation relations. Simulation results show the performance improvement of the proposed method compared with the conventional far-field method.