An Extend Kaiser Distribution Optimization Phase Compensation Algorithm for Terahertz Airborne SAR Imaging

A terahertz (THz) airborne synthetic aperture radar (SAR) with a carrier frequency of up to 220 GHz is developed. However, due to the short wavelength of THz, the motion compensation (MOCO) algorithm suitable for submeter resolution SAR systems becomes ineffective. To address this issue, we propose an extended Kaiser distribution optimization (EKDO)-based phase compensation algorithm for airborne THz SAR imaging. First, a subaperture division strategy is employed to divide the full-aperture data into multiple subapertures. The envelope error and phase error are roughly compensated using the combination of inertial measurement unit (IMU) and global positioning system (GPS) data. Then, the linear error of the compensated echo is estimated using the Doppler centroid estimation. Subsequently, the EKDO MOCO algorithm proposed in this article is used to compensate for the quadratic phase error. In the third step, residual errors are compensated using a high-order phase error estimation (HPEE). Finally, real data from experiments conducted in four different types of scenarios all confirmed the effectiveness and validity of the algorithm.