Motion Compensation for Squint SAR Based on INS and Spatial Uniform Reconstruction

In highly squinted-looking synthetic aperture radar (SAR) imaging, the motion errors of the radar platform exhibit severe spatial variability. The three-dimensional motion errors along the beam radial, tangential, and height directions are severely coupled. Traditional motion error compensation methods can only achieve focusing at the beam center, while image defocusing occurs at the beam edge due to the presence of spatially variant residual errors. This paper proposes a method for compensating spatially variant motion errors in highly squinted-looking SAR based on inertial navigation system (INS) data and uniform reconstruction in the imaging oblique plane. This method establishes a motion compensation model within the imaging oblique plane and performs spatial three-dimensional decomposition and geometric reconstruction of inertial navigation positions to implement spatial differential compensation for imaging motion errors in highly squintedlooking SAR within the imaging oblique plane. Simulation and experimental results show that this method can achieve precise focusing of targets across the entire beam range.