Accurate fourth-order doppler parameter estimation approach for geosynchronous SAR

摘要

Geosynchronous Earth orbital Synthetic Aperture Radar (Geo-SAR) is characterized by short revisit cycle and large observe swath, and thus shows potential for different applications such as frequent monitoring, ultra wide swath imaging, and natural risks prevention. As it has an orbital altitude about 35,790km, the Doppler parameter estimation method of Geo-SAR is different from any other low Earth orbital SAR(Leo-SAR) systems. To deal with the problems caused by long integration time and the Earth rotation, the paper presents a straightforward fourth-order Doppler parameter estimation approach which can address Geo-SAR, and the orbital eccentricity and the ellipsoidal earth model are both considered in the algorithm. At last, the influence of satellite attitude errors is analyzed based on the theory, and the differences of Doppler characteristic between Leo-SAR and GeoSAR are put forward.