The SAR Processing System Raw Data Processor (SPS RDS) computer program is used in the Alaska SAR Facility (ASF) to scan and decode raw data that have been downlinked from the European Remote Sensing Satellite (ERS), the Japanese Earth Resources Satellite (JERS), and the RADARSAT (a Canadian Earth-observation satellite) and recorded on high-density digital tape or disk. ["SAR" means "synthetic-aperture radar."] In its scanning role, the program reads a recorded downlink bit stream, performs PRN decoding as needed, extracts auxiliary information to identify data-acquisition times, correlates this information with spacecraft state vector information to determine locations, and maps the locations to predefined fixed frames along an orbit track. These frames are stored in an archive as they become available, and are subsequently interrogated when requests for generation of image products are received. In its decoding role, this program converts a downlink bit stream that pertains to a requested frame into files that contain decoded engineering and SAR signal data that are compatible with the computers and programs used in further processing of SAR data into final image and image data products.

This program was written by Eugene Chu and Tuan Truong of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp  under the Information Sciences category.

This software is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393-3425. Refer to NPO-20711.

NASA Tech Briefs Magazine

This article first appeared in the March, 2001 issue of NASA Tech Briefs Magazine.

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