A Novel High-Precision Terahertz Video SAR Imaging Method

Terahertz video synthetic aperture radar (THz-ViSAR) is emerging as a key technology for dynamic situational awareness and precise imaging of moving targets. However, the existing systems prioritize high frame rates at the expense of the dwell time, which degrades the azimuth resolution. To address this issue, we propose an improved video synthetic aperture radar (ViSAR) framework that can extend the synthetic aperture time and improve the image quality. First, the keystone transform (KT) is utilized to correct range cell migration, enabling accurate phase error estimation for high-resolution imaging. Moreover, unlike traditional methods without full-aperture imaging, our technique synthesizes a full-aperture phase error model by estimating subaperture phase errors, which can contribute to compensate for overall motion errors and generate high-resolution full-aperture SAR images. Airborne field experiments demonstrate the effectiveness of the proposed method, achieving the full-aperture high-resolution imaging while maintaining practical frame rates in dynamic surveillance scenarios.