SPECAN techniques for range and azimuth ScanSAR processing

Recently, there is a growing interest in Scanning SAR systems (ScanSAR) for their wider swaths. In this framework, efficient algorithms for generating ScanSAR images from raw data are demanded for browsing purposes or for on-board image generation. The SPECtral ANalysis method (SPECAN) and its variations are very appropriate for efficient SAR processing in both range and azimuth, when no full resolution is demanded. In the case of azimuth ScanSAR, that condition is naturally met due to the burst mode that does not acquire the whole Doppler spectrum. However, several problems arise due to the spectral analysis operation and its practical implementation. On the other hand, matched filtering for range processing presents a different scenario related to SPECAN processing because the signal contains a fixed quadratic phase, but different amplitude envelope. This work studies the processing of raw SAR data by the SPECAN techniques in both range and azimuth dimensions. The main contributions of this study are the analysis of the signals and the identification of their practical limitations related to SPECAN processing. The results show that SPECAN is a very promising method for efficient two-dimensional ScanSAR image generation when a specially designed algorithm concerning the signal dimension is applied.