DGDS/SINS integrated system used in SAR motion compensation

Nowadays higher resolution image from an airborne synthetic aperture radar (SAR) is needed in both civil and military usage, so more accurate motion compensation should be applied to the radar return to reduce image degradation caused by spurious motion of antenna phase center. The DGDS (differential global positioning system) and SINS (strapdown inertial navigation system) integrated system for SAR motion compensation was studied. The principle of DGPS/SINS pseudo-range rate integrated system was described, and the state equations and precise measurement model concerning position error were given. The algorithm of integrated system Kalman filter and error propagation of INS were presented. Simulation results show that even if medium accuracy INS instrument is used, the long-term position error of integrated system is about 1 m and the relative change of position error in the time interval of GPS measurement is smaller than 1 cm.