A Novel Multi-subaperture Motion Compensation Algorithm Based on Extended Quadratic Error Model for UAV SAR Imaging

Unmanned aerial vehicle (UAV) synthetic aperture radar (SAR) has been widely used in modern remote sensing applications. The requirements for high-resolution and real-time processing have grown rapidly in recent years. In practice, affected by flight deviations, motion errors are inevitable in returned echoes, leading to residual range cell migration (RCM) error and azimuth phase error (APE) at the same time. The SAR image formation algorithm in the frequency domain is considered efficient. While some operations, such as RCM correction, can break the linear relationship of errors between the range and azimuth direction, making motion compensation complicated. This paper derived the relationship between the residual RCM and APE based on the quadratic error model and proposed a novel multi-subaperture motion compensation (MOCO) method, which can be applied to high-order errors. Simulations are provided to verify the correctness and effectiveness of the method.