Alaska SAR processor implementation for JERS-1

Examines the synthetic aperture radar (SAR) data processing algorithms used by the Alaska SAR Facility (ASF) for Japan´s first Earth Resources Satellite (JERS-1) SAR data. The algorithms are somewhat similar to those used for the European Space Agency´s (ESA) first Remote-Sensing Satellite (ERS-1). The Alaska SAR Processor (ASP) processor for ERS-1 was upgraded in both the hardware and software to handle JERS-1 input data. To minimize tape interface time at every image region for raw data input, the JERS-1 preprocessing and main processing are implemented in a “two pass” operation. The important pre-processing highlights two features: (1) signal measurement and (2) Doppler measurement, which are performed by a “two dimensional FFT” (2DFFT) algorithm. The custom pipeline architecture performs the main processing with controls similar to those used with ERS-1 except the control registers are set up for L-band rather than for C-band. Finally, system performance of the processor for the SAR image processing of JERS-1 data is reviewed