A Two-dimensional Attitude Steering Method to Compensate Doppler Centroid in GEO SAR

The paper proposes a method of two-dimensional attitude steering to compensate Doppler centroid in Geosynchronous Earth Orbit Synthetic Aperture Radar (GEO SAR). By guaranteeing the beam illuminating the earths surface, Doppler centroid is compensated to zero by controlling the beam center direction. Firstly, for showing the necessity of two-dimensional attitude steering, Doppler centroid without yaw control and under one-dimensional yaw steering are analyzed. Then, based on the intersection line between the zero-Doppler plane and the earths surface, the calculation expression of beam center direction at any position of the satellite is deduced to compensate Doppler centroid to zero under the satellite obit coordinate. Simulation experiments validate the effectiveness of the proposed method.