DORIS - DAYS Toulouse May 2-3, 2000 DORIS Doppler Orbitography and Radiopositioning Integrated by Satellite  Basic system concept  Main missions  Schedules  Conclusions

DORIS - DAYS Toulouse May 2-3, 2000 Satellite with DORIS instrument B.O. : Orbitography Beacon of the permanent system network (Quartz USO Precisely positionned meteo data and beacon status transmission) B.M. : Master Beacon (B.O. + System time and frequency references + Instruments control & mission uploading) DORIS Mission and System Center Users Beacons NETWORK B.C. : Customer Beacon to be positionned (idem B.O.can be field packaged) DORIS system Overview B.O.T. : Time reference and Orbitography Beacon DORIS GROUND SEGMENT

DORIS - DAYS Toulouse May 2-3, 2000 DORIS/SPOT DORIS/TOPEX1992 DORIS/SPOT DORIS/SPOT DORIS/ENVISATMid 2000 DORIS/JASONEnd 2000 DORIS/SPOT DORIS Space segment

DORIS - DAYS Toulouse May 2-3, 2000DORISDORIS

Main missions  Precise orbit determination for Topex/Poseidon and Jason:  Altitude of Topex/Poseidon accurate to within three centimetres, on radial component in support to scientific (altimetry) mission performance  Jason to provide centimetre accuracy  Accurate location of ground beacons  to establish and maintain the terrestrial reference system used for altimetry measurements  for geodetic and geodynamics applications  Accurate autonomous navigation capability  Models improvements:  gravity field, air drag, ionosphere, troposphere. DORIS

DORIS - DAYS Toulouse May 2-3, 2000 Main missions Orbit determination (1/2)  Doris was originally designed for precise orbit determination in support of altimetry satellite missions:  within 5 cm for Spot 2  3 cm for Topex radial component  Objective of 1 cm for Jason, thanks to improved gravitational models and cross utilization of other geodetic technics (GPS, Laser, …). DORIS

DORIS - DAYS Toulouse May 2-3, 2000 Main missions Orbit determination (2/2)  Real time navigation:  Thanks to on-board measurement processing by DIODE software (included in Doris software), and demonstrated in Spot 4,  Less than 30 cm rms 3 axes achievable on Jason,  Time synchronisation: 3 micro seconds wrt TAI or UTC time scale.  Location station calibration (radar, 2 GHz networks)  Precise estimation of altitude control thruster efficiency (Spot) DORIS

DORIS - DAYS Toulouse May 2-3, 2000 DORIS PERFORMANCE Orbit determination mission DORIS orbit determination products AccuracyTurnaroundApplication Initial orbit10 centimetres48 hours Satellite operation Precise orbit3 centimetres1 month Processing of satellite altimetry measurements Calculation of manœuvre efficiency Calibration of other measurement systems (radar, 2GHz location, etc.) Onboard real time Precise Doris (Jason) Single-frequency Doris (navigation) <1 metre 10 metres Immediate Satellite autonomy Auxiliary data for satellite payload Delayed time (ground) Real time (onboard)

DORIS - DAYS Toulouse May 2-3, 2000DORISDORIS  Geodesy accurate absolute and relative location  Geodynamics plate tectonics  Volcanology surface deformation monitoring  Glacier monitoring  Landslide monitoring  Construction and monitoring of large civil engineering structures Main missions Location Location

DORIS - DAYS Toulouse May 2-3, 2000DORISDORIS  Precise point positionning  Doris provides fast data on ground beacons positions;  The CLS company provides Doris services on an operational, commercial basis:  precise point coordinates at remote locations: islands, platforms, secondary reference points, etc.  tying local geodetic networks into reference networks,  long-term measurement of geodynamic drifts,  remote monitoring of natural hazard areas (e.g., seismic zones, volcanoes, landslides). Geodetic applications (1/2)

DORIS - DAYS Toulouse May 2-3, 2000DORISDORIS  Earth Rotation  Doris provides Earth rotation parameters with a one-day resolution, used to study of dynamic interactions between fluid and solid Earth components.  Earth Center position Geodetic applications(2/2) Source IERSDORIS

DORIS - DAYS Toulouse May 2-3, 2000DORISDORIS  Doris was accepted in 1994 as a new technique of the International Earth Rotation Service.  IERS objectives include the establishment and maintenance of a high accuracy Earth reference system.  Doris contributed to ITRF 94, 96, 97 and will contribute to ITRF  Because of its performances, the international community proposed to create an International Doris Service at the last general assembly of the IGGU (July 1999). Reference systems

DORIS - DAYS Toulouse May 2-3, 2000DORISDORIS  Doris can be used to measure tectonic plates relative motions of the terrestrial lithosphere;  Measurement accuracy allows validation of cinematic models and determination of local phenomena. GeophysicsGeophysics

DORIS - DAYS Toulouse May 2-3, 2000DORISDORIS

DORIS PERFORMANCE Ground beacon location Results within 2 or 3 days Operational geodesy (1 m to 15 cm over 1 day) Results within 1 week Results within a few months High precision geodesy (10 to 0.1 cm over 1 year) Altimeter reference Measurements, In days cm 10 cm 0 cm

DORIS - DAYS Toulouse May 2-3, 2000DORISDORIS  Improvement of the Earth gravity field;  Global ionosphere mapping for radio-electric signal propagation error correction;  Calibration and validation of other space geodesy techniques. Other DORIS applications

DORIS - DAYS Toulouse May 2-3, 2000 DORIS General schedule Earth rotation Navigation Gravity field Accurate location Precise orbit Topex-Poséidon Envisat 1 Pleïade Spot 2 Spot 3 Spot 4 Spot 5 Jason 1

DORIS - DAYS Toulouse May 2-3, 2000 Mass 20 kg 10 kg DORIS Instrument evolution DORIS Data st generation, Spot 2, 3 and 4, Topex/Poseidon No redundancy 2 nd generation, Envisat No redundancy 2 nd miniaturized generation, Jason, Spot 5 No redundancy miniaturized generation Mass produced

DORIS - DAYS Toulouse May 2-3, 2000 DORIS PERFORMANCE Ground location beacon evolution Mass 3 rd generation, enhanced performance, Date kg 10 kg 0 1 st generation, 50 GLBs produced 2 nd generation 25 GLBs produced

DORIS - DAYS Toulouse May 2-3, 2000  The Doris accurate location system provides outstanding performance.  It has been constantly improved since it became operational in the early 90’s and additional improvements are already planned for the next ten years.  It will continue to complement existing GPS, VLBI and SLR systems and at the same time it will provide unique capabilities such as:  a worldwide ground network,  precise measurements of vertical crustal movements (better than 1 mm/year)  presice measurement of temporal variations of geodetic parameters (geocenter movement). ConclusionsConclusions