DORIS is a system developed by CNES, IGN and GRGS (*) for precise positioning and navigation purposes.
It relies upon a dense network of ground beacons and receivers carried onboard satellites.
The DORIS receivers process the beacon twin-frequency up-links in order to measure the radial speed between the satellite and the beacons.
Applications of DORIS
High precision orbit determination - High precision positioning
Ground based processing of raw measurements allows very precise orbit determination and ground beacon positioning.
The ultimate precision is at the centimeter level.
Autonomous navigation
Real-time positioning is achievable with the high accuracy (twin-frequency) instrumentation or with the Navigation receiver (2 GHz single-frequency).
The real-time computation is carried out by the DIODE software program developed by CNES.
This application is fully operational and installed onboard of many satellites.
DORIS can be used for various missions such as:
• altimetry missions
• SAR or optical imagery,
• geodesy,
• cartography,
• geophysical studies (earth potential, pole motion, ...).
Time transfer
DORIS instruments can provide a synchronisation pulse to other instruments or time tag an external pulse. This allows to link a satellite time base to a ground time base (UTC, TAI, etc.).
Other applications
Studies are under way in order to extend the application of DORIS in the following fields:
• MEO and GEO satellites navigation or orbit monitoring,
• precise time synchronisation (better than 30 ns).
For more information about Doris
• the International DORIS Service (IDS) provides DORIS data for the world scientific community (raw measurements, orbit products, station coordinates, Earth parameters) at the web site http://ids.cls.fr
• information about the DORIS system and its applications are available at the web site http://doris.mission.cnes.fr
(*) CNES: the French space agency
IGN: the French geographic institute
GRGS: Space Geodesy Research Group