Geosynchronous SAR image formation based on advanced hyperbolic range equation

Based on an advanced hyperbolic range equation (AHRE), this study presents an advanced Range Doppler (RD) algorithm for Synthetic aperture radar on geosynchronous satellites (GEO SAR) cases. Since the orbit altitude reaches up to about 36,000 km in GEO SAR, the integration time becomes longer and curved flight path is generated accordingly. Thus, the AHRE is introduced in this paper, which can compensate the error of the conventional hyperbolic range equation (CHRE) in GEO SAR. Then, the two dimensional (2-D) frequency spectrum (PTFS) expression of a point target is obtained by the method of series reversion (MSR). Finally the advanced RD algorithm based on the new spectrum is proposed. Point target simulation results show that the presented algorithm obtains fine performance in GEO SAR cases.