What are Radarsat orbit files?
All orbit data used in processing RADARSAT imagery are derived from actual orbit measurements of the spacecraft during transits over the Telemetry, Tracking and Command (TT&C) Stations. Predicted orbit files are determined in advance of a particular orbit and distributed to the various processing stations. In addition, predicted data is uploaded to the satellite and is included in the Auxiliary data that is subsequently downlinked to the ground receiving station. Definitive orbit data files are prepared approximately 24 to 48 hours after the relevant orbit pass. Definitive orbit data may be more accurate and thus reduce the absolute location error in the resulting image. There should be no noticeable difference in image distortion.
