Confocal tomography imaging in near-field based spherical wave focusing convolution integral algorithm

Tomography imaging of synthetic aperture radar can realize 3D tomography although its algorithm is simple, computation quantity is small, but is mainly suitable for the far field conditions. In addition, by increasing the number of baseline to improve the resolution will greatly increase the system complexity. According to the above problems, a tomography imaging technique in near-field using confocal circular SAR is proposed. Two techniques of synthetic aperture and confocal imaging are combined to achieve space-time confocal imaging using SAR on a circular or curved orbit. The results of digital simulation and experiment show that the proposed algorithm overcomes altitude ambiguity and has the capability to extract 3-D imaging information from a target scene.