A new approach for spotlight geosynchronous SAR data focusing

Besides the evident superiority, the Geosynchronous Earth orbit synthetic aperture radar (Geo-SAR) system meets great more challenges than the current Low-Earth-Orbital SAR (Leo-SAR) and the Medium-Earth-Orbit SAR (Meo-SAR). The signal processing approach for spotlight mode Geo-SAR is discussed in this paper. A new range model called the sixth-order Doppler parameter range model (DRM-6) is derived based on the accurate sixth-order Doppler parameter calculation algorithm. The accuracy of Hyperbolic Range equation (HRE) and the DRM-6 are compared. According to the non-linear property of the synthetic aperture, the Back projection algorithm is chosen for image formation. At last the simulation results validate that DRM-6 has a good effect on the L-Band spotlight Geo-SAR system with a azimuth resolution around 2m.