A New Imaging Approach for Burst Mode Synthetic Aperture Radar

Burst imaging schemes such as ScanSAR and Terrain Observation by Progressive Scans (TOPS) are often adopted to obtain wide swath coverage by synthetic aperture radar (SAR) systems with electronic beam steering in elevation. Long burst trains with zero padding in the inter-burst intervals can be focused by standard stripmap processors for the phase preserving product. However, this approach is less efficient due to the larger azimuth data extension. We discuss an efficient imaging approach for burst mode SAR. The key point of the proposed procedure is a postfiltering step after standard stripmap processors, which employs an azimuth convolution between the focused SAR data and the selected chirp signal. The postfiltering step is generalized by a two-step focusing technique formerly proposed for spotlight/sliding spotlight SAR. This approach extends the focusing capacity of standard stripmap processors to process burst mode raw data. Moreover, it is highly efficient, as it requires a very limited azimuth data extension.