Extended three-step focusing algorithm for sliding spotlight and tops data image formation

This paper conducted thorough research to the theory of space-borne Sliding spotlight and TOPS data processing. First, the unified definition of hybrid factor of both TOPS and sliding spotlight mode was given. Then, the hybrid factor was analyzed and amended along the range direction combined the geometry model. Combined with amended hybrid factor, azimuthal time-frequency characteristic of was analyzed and discussed in detail by mathematic derivation. Based on the analysis, an efficient and precise extended three-step image formation algorithm was presented for sliding spotlight and TOPS image formation. Finally, the imaging results justify the effectiveness of the extended three-step algorithm.