Abstract: To improve the repeating cycle of Geo-SAR through prompt attitude control method, the staring mode attitude control property and system parameters’ performance of Geo-SAR with reflector antenna are presented. The approach illuminated in this paper aims to shorten the attitude control time, and to improve the revisiting effect. Firstly, Geo-SAR staring mode model and Doppler history are illustrated and compared with those of low earth orbital SAR (Leo-SAR). Its maximum yaw angle to be compensated for broadside imaging is about ±76° when traditional two-dimensional yaw steering (2D-YS) method is used. A new twodimensional pitch and roll squint control (2D-PRSC) algorithm is advanced, which can make satellite continuously stare at any scene in the whole orbital period. The maximum attitude control angle is about ±7.2°, and the capability of satellite is obviously improved. Finally, Geo-SAR fast BP imaging algorithm is illustrated in this paper. The point target with 25m×25m resolution is simulated, the imaging results are good and meet the theory parameters. The simulation results show that the new method in this paper is correct. As the reference scheme for attitude system design, the method can shorten the Geo-SAR attitude control time to about 1/10 of the original value.

Key words: Geo-SAR, reflector antenna, 2D pitch and roll attitude control, staring mode, attitude control time