Vibration Compensation of Airborne Terahertz SAR Based on along Track Interferometry

In airborne terahertz synthetic aperture radar (THz-SAR), the phase error caused by high-frequency vibration of the platform can result in not only defocusing, but also the emergence of unwanted ghost targets. To tackle this problem, we propose a vibration estimation and compensation method for the dual-channel THz-SAR based on along-track interferometry (ATI). Compared with the state-of-art single-channel-based compensation methods, the proposed method is advantageous in that it can stay effective without isolated dominant scatter points in the scene. This letter first analyzes the relationship between the along-track interferometric phase of the stationary targets' echo and the instantaneous radial velocity of the platform's high-frequency vibration. Then, by using the interferometric phase, the phase error caused by vibration is estimated and compensated. Simulation results show that the proposed method can effectively compensate the phase error caused by multicomponents high-frequency vibration without using the information of dominant scatter points.