Research On Non-interpolated Fast Backward Projection Imaging And Error Compensation Techniques For Airborne SAR

Synthetic Aperture Radar(SAR)is a microwave remote sensing technology that operates continuously and under all weather conditions.SAR is characterized by its long operational range,strong penetration capability,and high resolution,making it widely applicable in various fields such as military,civilian,and scientific research.Time-domain imaging algorithms are primarily used for processing and image reconstruction of SAR signals.Compared to frequency-domain algorithms,time-domain algorithms offer advantages such as high computational accuracy,broad applicability.As a result,time-domain imaging algorithms find widespread application in SAR signal processing and image reconstruction.Among these algorithms,the Cartesian factorized back-projection(CFBP)algorithm stands out for its high computational accuracy,fast imaging speed,and avoidance of extensive two-dimensional interpolation.However,a challenging research problem in the application of the CFBP algorithm is its integration with self-focusing error compensation.Therefore,this paper focuses on investigating self-focusing error methods combined with CFBP imaging in various modes of airborne SAR.The specific research includes the following aspects:1、To address the phase error and spectral spreading issues in the subapertures of the Cartesian factorized back-projection(CFBP)algorithm in the airborne SAR’s spotlight mode,this study proposes a specific spectral compression method to resolve the spectral spreading problem.By eliminating the ineffective motion error compensation resulting from spectral spreading,the study designs an autofocus error compensation algorithm to mitigate the impact of phase errors on imaging and improve the image focusing quality.This paper demonstrates the feasibility of combining the CFBP algorithm with self-focusing techniques through simulation experiments.2、In the context of airborne SAR with large squint angles,error issues pose challenges to the application of the Cartesian factorized back-projection(CFBP)imaging algorithm.Through analysis and derivation in the imaging and data domains,this study designs a spectral rotation parameter matrix to correct the aperture spectrum and utilizes specific spectral compression and wavenumber spectrum correction techniques to address the spectral aliasing problem in squinted spotlight mode.By analyzing the results of the simulation experiments,the effectiveness and performance advantages of the proposed method have been validated.