A Novel 3D Imaging Method for Region of Interest with Airborne MIMO-SAR

In observed scene, there would exist target or region of interest (ROI), which we are more concerned about. Multiple-input-multiple-output synthetic aperture radar (MIMO-SAR) can form large aperture by limited antenna elements, which can improve observing efficiency and azimuth resolution. Forward-looking MIMO-SAR can overcome the blind zone of Side-looking SAR and Squint-looking SAR with respect to the direction in front of radar platform, and Down-looking MIMO-SAR can reconstruct 3D image of observed scene under radar platform. Combining the advantages of the both, a novel 3D imaging method for ROI is proposed for the detection and imaging of target in sparse scene. Firstly, a forward-looking MIMO antenna array (FLMIMOAA) is utilized to operate 2D pre-imaging of observed scene, then the ROI is confined and positioned by corresponding searching algorithm. At last, compressed sensing (CS) theory is utilized in Down-looking MIMO antenna array (DLMIMOAA) for 3D imaging of ROI. Compared with conventional SAR imaging mode for ROI, which often needs twice flights and only gets 2D image of ROI, this mode can obtain clear 3D imaging of ROI only by one flight, the work efficiency is much higher, the information of ROI is more abundant, and the size of data is remarkably reduced by using the fast searching algorithm and CS reconstruction. The mode based on proposed method would have broad application prospects in geographic remote sensing, geological survey and war-field reconnaissance. The feasibility and high imaging quality of corresponding methods are verified by the simulation results.