Abstract:

Due to the characteristic of phase gradient autofocus(PGA) in the scene without special significant target of the application ineffective and minimum entropy and maximum contrast computing excessive autofocus methods,this paper proposes a new method which corrects range-dependent error.The characteristic of phase error of the local range-independent was used to estimate the phase error of each sub-block data.According to the motion characteristics of the platform of the aircraft and the respective sub-blocks of the phase error has been estimated,to calculate the aircraft platform in the vertical direction of the slant range error.The slant range error that has been estimated was used to fit the entire phase error in the range direction,and range-dependent phase error curve was got.Simulation result verifies the validity of the method,and eventually better imaging was got.

Key words: SAR;Range-dependent error;phase gradient autofocus