A ViSAR Imaging Method for Terahertz Band Using Chirp Z-Transform

Video synthetic aperture radar (ViSAR) as a new imaging mode has received more attention in recent years. In this mode, ViSAR system needs to persistently form a sequence of images while collecting data. For ViSAR, the frame rate needs to exceed 5 Hz to track maneuvering ground targets. Therefore, ViSAR system generally works in terahertz band. To avoid the 2-D interpolation of the polar format algorithm (PFA), a ViSAR imaging method is proposed in this paper. Based on the small synthetic angle characteristic of THz ViSAR, this method decomposes 2-D interpolation into range and azimuth interpolation, which is implemented by chirp Z-transform (CZT). The effectiveness of this method is validated by the simulation results in 0.3 THz.