Hybrid SAR-ISAR imaging of ships

A radar imaging theory for synthetic aperture radar (SAR), inverse SAR (ISAR), and hybrid SAR-ISAR is developed from the Fourier transform of k space samples. The rotations due to the radar and the object are combined in the hybrid SAR-ISAR case, and a small angle approximation is derived. The analysis presented is limited to small angles of rotation and constant angular velocities; however, extensions to this have been derived and are briefly discussed. Of particular interest are the expected image orientation and the effect of inaccurate knowledge of motion parameters on image quality. Both of these are considered in theory and then demonstrated in simulations based on multisource models of ship radar cross section