Airborne interference SAR system and method based on POS

The present invention relates to the field of information acquisition and processing technology, in particular, it relates to an airborne interference SAR system based on POS and its method. Said method includes the following steps: (1), utilizing POS sensor mounted on the platform to induce motion parameter of platform, and packaging and recording the motion parameter; (2) after the flight is completed, processing the motion data including the information of position, speed, acceleration, angular velocity and attitude of platform with twin antenna which are real-time obtained and recorded by POS sensor; (3) making the motion data obtained after POS treatment be aligned with radar data in time; (4) using the data obtained by means of POS treatment to make motion compensation for radar data; (5), making the radar data undergo the process of imaging system treatment to obtain two complex-valued SAR images; and (6), utilizing data obtained by means of POS treatment and making said data undergo the process of interference processing system treatment so as to obtain terrain information.