Radarsat-1 image quality and calibration - Continuing success in extended mission

RADARSAT-1, the first Canadian SAR remote sensing satellite, was launched on November 4, 1995. After commissioning, it was put into routine operations on April 1, 1996. Since then, it has been operating successfully, even after completing its five and a quarter years of design lifetime, and providing data to users for their intended applications. Significant effort continues to be expended in the provision of high quality products to users generated by the Canadian Data Processing Facility (CDPF). After initial calibration, both single beams and ScanSAR are monitored routinely as part of the Maintenance Phase for image quality performance. Image quality is monitored through periodic measurements of impulse response function, location error and radiometry, using images of the Amazon Rainforest and RADARSAT-1 Precision Transponders (RPTs). ScanSAR radiometry is also monitored through periodic measurements of the Amazon Rainforest. A major upgrade of the ScanSAR processor completed recently in CDPF made significant improvements in image quality and radiometry. An experiment was conducted to determine if antenna pattern change was due to the heating or cooling of Variable Phase Shifters (VPS) forming antenna beams. It was concluded that changes in beam pattern are not due to temperature variations. New methods and software tools have been developed to improve operational efficiency. Also, a new methodology was implemented to assess spacecraft roll variation, using ocean images for improved characterization of spacecraft attitude performance. This methodology was used in several experiments that were conducted to gain a better understanding of image quality when operating the spacecraft in ADM3 mode. Crown Copyright (C) 2003 Published by Elsevier Ltd on behalf of COSPAR. All rights reserved.