Improved Secondary Range Compression focusing method in GEO SAR

The paper firstly analyses the error caused by the linear trajectory model and the Fresnel approximation because of the long synthetic aperture time in Geosynchronous Synthetic Aperture Radar (GEO SAR), and then proposes an improved Secondary Range Compression (SRC) focusing algorithm to overcome the effect of linear trajectory model and the Fresnel approximation. The improved focusing algorithm adopts the curved trajectory model on basis of Norm operator to remove the error caused by the linear trajectory, derives and compensates the third order phase in two-dimensional frequency domain to overcome the large range migration. Finally, imaging results verify the improved focusing algorithm.