Range Migration Algorithm for Near-Field MIMO-SAR Imaging

In this letter, a 3-D range migration algorithm for multiple-input multiple-output synthetic aperture radar imaging is proposed. The accurate expression of the signal spectrum is derived by utilizing the spherical wave decomposition. This method compensates for the curvature of the wavefront in wavenumber domain and achieves the 3-D Fourier transform of the reflectivity map through a dimension-reducing accumulation operation. Its fast Fourier transform-based imaging scheme provides high imaging efficiency. In addition, this method does not take the plane wave approximation and can be applied in near-field imaging scenes. Both theoretical analysis and experimental results show that the proposed method can reconstruct the 3-D image as accurately as the backprojection algorithm but with much lower computational load.