Method About Motion Error Compensation For Back Projection Imaging In Time Domain Of SAR

Synthetic Aperture Radar(SAR)is a high resolution imaging radar.The time domain back projection imaging algorithm is one of the SAR imaging algorithms which is suitable for any configuration.The algorithm assumes that the radar is located on the ideal track,however,the motion error will cause image defocused.It is of great significance to study the motion compensation method combined with the time domain back projection imaging algorithm.Focusing on the motion error compensation in the time domain back projection imaging,this paper mainly carries on the following work:Build the model of motion error and analysis the impact on imaging results.According to the geometrical configuration of SAR,we establish the distance with motion error.Then we can get the quantitative relation between phase error and the distance deviation.Finally we analysis the impact on imaging results through the simulation.Research the motion compensation method in back projection algorithm(BP).The relationship between the image quality evaluation function and the position deviation of the carrier is derived.Build the optimization model of image quality evaluation.Estimate the trajectory with motion error based on the BP algorithm.Make some simulation to verify the effectiveness of this method.Autofocus method for fast factorized back projection(FFBP).Build the model with motion error based on FFBP.Present the autofocus method combined with coordinate decent based on the maximum image sharpness.Make some simulation to verify the effectiveness of this method.Research the motion compensation method with FFBP based on hardware measurement.Research the motion compensation with the fitting in curved track based on the high precision azimuth data of the radar platform during the movement.Make some simulation to verify the effectiveness of this method.All the methods above are verified by simulation.Simulation results show that the trajectory estimation in BP,autofocus method in FFBP,the motion compensation in FFBP based on hardware measurement are great ways to compensate the motion errors and gain the precise image.