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.
This Brief includes a Technical Support Package (TSP).
Software for Preprocessing of Raw SAR Data
(reference NPO-20711) is currently available for download from the TSP library.
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Overview
The document provides an overview of the SAR Processing System Raw Data Processor (SPS RDS), a software program developed for the Alaska SAR Facility (ASF) at NASA's Jet Propulsion Laboratory (JPL). The SPS RDS is designed to process raw data from various international polar-orbiting remote sensing satellites, including the European Remote Sensing Satellite (ERS), the Japanese Earth Resources Satellite (JERS), and Canada's RADARSAT.
The SPS RDS performs two primary functions: data scanning and data decoding. In the data scanning role, the program reads recorded downlink bit streams from high-density digital tapes or disk files. It performs pseudorandom noise (PRN) decoding as necessary, extracts auxiliary information to identify data acquisition times, and correlates this information with spacecraft state vector data to determine locations. These locations are then mapped to predefined fixed frames along the satellite's orbit track, which are archived for future use.
In its data decoding function, the SPS RDS converts the downlink bit streams related to specific requested frames into files that contain decoded engineering and synthetic aperture radar (SAR) signal data. These files are compatible with general-purpose software-based SAR processors, such as the ScanSAR Processor (SSP) and Precision Processor (PP) used at ASF. The SPS RDS has evolved over time to include robust error handling capabilities, allowing it to retrieve usable data even from noisy downlinks or damaged tape media.
The document also highlights the successful application of the SPS RDS in various scientific campaigns, including mapping the Amazon rainforest, supporting the Antarctic Mapping Mission, and conducting the Arctic Snapshot mission. The software is available for commercial licensing, and interested parties are directed to contact Don Hart at Caltech for more information.
Additionally, the document includes a disclaimer stating that references to specific commercial products or services do not imply endorsement by the U.S. Government or JPL. Overall, the SPS RDS is a critical tool for processing and distributing SAR data, contributing significantly to remote sensing research and applications.
