A combined mode of tops and inverse tops for mechanical beam steering space-borne SAR

To realize TOPS (Terrain Observation by Progressive Scan) mode with a mechanical beam steering space-borne SAR (Synthetic Aperture Radar) shows promising performance because it can take advantage of both TOPS and mechanical beam steering. But the standard TOPS mode needs antenna beam to turn immediately from forward to backward when switch between sub-swaths. It is difficult to mechanical beam steering system. This paper proposes a combined mode of TOPS and inverse TOPS for mechanical beam steering spaceborne SAR system to avoid immediately turning. The principles of the new mode are described and then the system design methodology is discussed. The results can also be extended to the mosaic mode easily.