RADARSAT-1 Image Quality and Calibration - Continuing success in extended mission
Abstract
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. Since 1998 calibration measurements indicated changes in the characteristics of several previously calibrated elevation antenna patterns. An experiment was conducted to determine if this 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. Matures performance of VPS is probably the cause of these changes. Compensation for beam pattern changes are made in the processor by re-calibrating these beams. New methods and software tools have been developed to improve operational efficiency. This includes a tool to facilitate acquisition planning of calibration image and tracking performance of image quality parameters. Also, a new methodology was implemented to assess spacecraft roll variation, using ocean images for improved characterization of spacecraft attitude performance. The measured results indicate that RADARSAT-1 image quality is better than specification and that it is maintained.
- Publication:
-
34th COSPAR Scientific Assembly
- Pub Date:
- 2002
- Bibcode:
- 2002cosp...34E.466S