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					                                      DORIS
          Doppler Orbitography and Radiopositioning
                    Integrated by Satellite

                                               Basic system
                                                concept


                                               Main missions


                                               Schedules


                                               Conclusions


DORIS - DAYS Toulouse May 2-3, 2000
                                               DORIS
                                       system Overview

                                    Satellite with DORIS instrument




                                                                           B.O.T. : Time reference and
                                                                             Orbitography Beacon




                           B.M. : Master Beacon
                                    (B.O.
                                                                   B.O. :
                                      +
      DORIS Mission and                                    Orbitography Beacon
        System Center           System time                                               B.C. : Customer
                                                     of the permanent system network
                          and frequency references                                           Beacon to be
                                                                (Quartz USO
                                      +                    Precisely positionned              positionned
                             Instruments control              meteo data and              (idem B.O.can be
                                      &                 beacon status transmission)         field packaged)
                             mission uploading)
                                                                                       Users Beacons NETWORK
                            DORIS GROUND SEGMENT




DORIS - DAYS Toulouse May 2-3, 2000
                                      DORIS
                                Space segment


                                          DORIS/SPOT 2    1990
                                          DORIS/TOPEX     1992
                                          DORIS/SPOT 3    1993
                                          DORIS/SPOT 4    1998
                                          DORIS/ENVISAT   Mid 2000
                                          DORIS/JASON     End 2000
                                          DORIS/SPOT 5    2001




DORIS - DAYS Toulouse May 2-3, 2000
                                      DORIS




DORIS - DAYS Toulouse May 2-3, 2000
                                      DORIS
                                 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 - DAYS Toulouse May 2-3, 2000
                                      DORIS
                             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 - DAYS Toulouse May 2-3, 2000
                                      DORIS
                              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 - DAYS Toulouse May 2-3, 2000
                      DORIS PERFORMANCE
                        Orbit determination mission

               DORIS orbit             Accuracy       Turnaround          Application
              determination
                products
                                                                      Satellite operation

                                                                   • Processing of satellite
Delayed       Initial orbit          10 centimetres   48 hours
                                                                    altimetry measurements
  time                                                             • Calculation of manœuvre
(ground)                                                            efficiency
                                                                   • Calibration of other
                                                                    measurement systems
              Precise orbit          3 centimetres     1 month      (radar, 2GHz location, etc.)


   Real     Onboard real time                                       • Satellite autonomy
                                      <1 metre
   time     Precise Doris (Jason)                     Immediate     • Auxiliary data for
(onboard)   Single-frequency Doris    10 metres                      satellite payload
            (navigation)




DORIS - DAYS Toulouse May 2-3, 2000
                                      DORIS
                                 Main missions
                                      Location
         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

DORIS - DAYS Toulouse May 2-3, 2000
                                       DORIS
                        Geodetic applications (1/2)


         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).



DORIS - DAYS Toulouse May 2-3, 2000
                                      DORIS
                       Geodetic applications(2/2)

                                              Source IERS   DORIS
         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



DORIS - DAYS Toulouse May 2-3, 2000
                                      DORIS
                             Reference systems

    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 2000.

    Because of its performances, the international community
     proposed to create an International Doris Service at the last
     general assembly of the IGGU (July 1999).


DORIS - DAYS Toulouse May 2-3, 2000
                                       DORIS
                                      Geophysics


          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.




DORIS - DAYS Toulouse May 2-3, 2000
                                      DORIS




DORIS - DAYS Toulouse May 2-3, 2000
                        DORIS PERFORMANCE
                             Ground beacon location
                               1-
                    Results within 2 or 3 days
   20 cm                Operational geodesy
                     (1 m to 15 cm over 1 day)
                                                     2-
                                            Results within 1 week

                                                                                3-
    10 cm                                                           Results within a few months
                                                                        High precision geodesy
                                                                      (10 to 0.1 cm over 1 year)
                                                                          Altimeter reference




     0 cm
              1 2      5        10                                  30
                                     Measurements, In days



DORIS - DAYS Toulouse May 2-3, 2000
                                      DORIS
                        Other DORIS applications


    Improvement of the Earth gravity field;

    Global ionosphere mapping                  for   radio-electric     signal
     propagation error correction;

    Calibration and          validation   of     other    space       geodesy
     techniques.




DORIS - DAYS Toulouse May 2-3, 2000
                                                               DORIS
                                                  General schedule
               90      91      92      93      94        95     96         97      98       99 2000              01     02 03   04



    Spot 2




              Topex-Poséidon


                                    Spot 3


                                                                     Spot 4

                                                                                                Envisat 1




                                                                                           Jason 1




                                                                                                        Spot 5
  Earth rotation    Precise orbit    Accurate location        Navigation        Gravity field


                                                                                                                      Pleïade



DORIS - DAYS Toulouse May 2-3, 2000
                                           DORIS
                               Instrument evolution
Mass       1st generation, Spot 2, 3 and 4, Topex/Poseidon
20 kg
                          No redundancy

                                                      2nd generation, Envisat


                                                             No redundancy

10 kg
                                                             2nd miniaturized generation, Jason, Spot 5


                                                                           No redundancy



                                                                         miniaturized generation

                                                                          Mass produced
   0
    1980                                    1990                                         2000             Data


DORIS - DAYS Toulouse May 2-3, 2000
                     DORIS PERFORMANCE
                  Ground location beacon evolution

    Mass
              1st generation, 50 GLBs produced
    20 kg



                                      2nd generation
                                      25 GLBs produced
    10 kg

                                                         3rd generation,
                                                         enhanced performance,


      0
       1980                           1990                     2000    Date



DORIS - DAYS Toulouse May 2-3, 2000
                                      Conclusions

     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).

DORIS - DAYS Toulouse May 2-3, 2000

				
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posted:10/19/2012
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