Millimeter-Wave Interferometric Synthetic Aperture Radar Imaging via Ground Projection

Due to the short wavelength, Millimeter-wave interferometric synthetic aperture radar (MMW-InSAR) imaging requires higher precision of the platform trajectory compared with other centimeter-wave bands. In the case of non-ideal trajectory, traditional SAR imaging methods may suffer from several problems, e.g. image defocusing and motion error correction. In addition, these methods mainly produce InSAR image via range-azimuth plane projection. If the terrain height is abruptly changed, these methods could cause serious geometric distortion in InSAR image. To overcome the disadvantages of these conventional methods in MMW-InSAR imaging, a modified back projection via ground projection (GP-BP) is proposed in this paper. In this theme, the echoes of the different antennas of MMW-InSAR are projected into the same ground space for both image focusing and interferogram extraction. Simulation and experiment results verify the effectiveness of GP-BP, and demonstrate that it can improve the quality of both image focusing and interferometric phase extraction in the condition of complex motion, and also can reduce the geometric distortion and the phase wrapping in the case of the abrupt terrain.