The Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) is a satellite system used for the determination of satellite orbits and for positioning. Sentinel-3 has one DORIS receiver and the data for its processing can be found here:
- Sentinel-3A: ftp://ftp.cddis.eosdis.nasa.gov/pub/doris/data/s3a
- Sentinel-3B: ftp://ftp.cddis.eosdis.nasa.gov/pub/doris/data/s3b
Example of DORIS antenna and receiver on-board Sentinel-3
Additional information about DORIS on Sentinel-3 satellites can be found here: