On-board ScanSAR processing: possibilities and perspectives

For classical SAR processing, on-board data processing remains at the present time unthinkable. However, with the ScanSAR resolution requirements of the wide-swath and global monitoring modes of the ENVISAT/ASAR, an on-board reconstruction can be considered, under some conditions. The considerable data rate reduction for the transmission to the ground (factor of at less 30) justifies the interest for such a solution. Taking into account today requirements of the space missions, a maximum of four ADPs 21020, in its space qualified version, could be available for ScanSAR data processing. On the basis of the most efficient ScanSAR schemes, the number of ADSPs 21020 required for a real time implementation is computed. The general conclusion recommends on-board processing in the global monitoring mode of ENVISAT, while emphasizing the possibilities in the wide-swath case.