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

DORIS - DAYS Toulouse May 2-3, 2000

DORISDORIS

Doppler Orbitography and Radiopositioning Doppler Orbitography and Radiopositioning Integrated by SatelliteIntegrated by Satellite

Basic system concept

Main missions

Schedules

Conclusions


Satellite with DORIS instrument

B.O. :

Orbitography Beaconof the permanent system network

(Quartz USOPrecisely positionned

meteo data and beacon status transmission)

B.M. : Master Beacon

(B.O.+

System timeand 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)

DORISDORISsystem Overviewsystem Overview

DORISDORISsystem Overviewsystem Overview

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

DORIS GROUND SEGMENT


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

DORISDORIS

Space segmentSpace segment


DORISDORISDORISDORIS


Main missionsMain 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.

DORISDORIS


Main missionsMain missionsOrbit determination (1/2)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, …).

DORISDORIS


Main missionsMain missionsOrbit determination (2/2)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)

DORISDORIS


DORIS PERFORMANCEDORIS PERFORMANCEOrbit determination missionOrbit determination mission

DORIS orbit determinatio

nproducts

Accuracy Turnaround Application

Initial orbit 10 centimetres 48 hours

Satellite operation

Precise orbit 3 centimetres 1 month

• Processing of satellite altimetry measurements• Calculation of manœuvre efficiency• Calibration of other measurement systems (radar, 2GHz location, etc.)

Onboard real timePrecise Doris (Jason)Single-frequency Doris(navigation)

<1 metre

10 metres

Immediate• Satellite autonomy• Auxiliary data for satellite payload

Delayedtime

(ground)

Realtime

(onboard)



Geodesyaccurate absolute and relative location

Geodynamicsplate tectonics

Volcanologysurface deformation monitoring

Glacier monitoring Landslide monitoring Construction and monitoring of large civil

engineering structures


LocationLocation


LocationLocation



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)Geodetic applications (1/2)Geodetic applications (1/2)Geodetic applications (1/2)



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)Geodetic applications(2/2)Geodetic applications(2/2)Geodetic applications(2/2)

Source IERS DORIS



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).

Reference systemsReference systemsReference systemsReference systems



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.

GeophysicsGeophysicsGeophysicsGeophysics




DORIS PERFORMANCEDORIS PERFORMANCEDORIS PERFORMANCEDORIS PERFORMANCEGround beacon locationGround beacon locationGround beacon locationGround beacon location

Results within 2 or 3 daysOperational geodesy

(1 m to 15 cm over 1 day)

Results within 1 week

Results within a few monthsHigh precision geodesy

(10 to 0.1 cm over 1 year)Altimeter reference

Measurements, In days

2-

3-

20 cm

10 cm

0 cm

1 2 5 10 30

1-



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 applicationsOther DORIS applicationsOther DORIS applicationsOther DORIS applications


DORISDORISGeneral scheduleGeneral schedule

DORISDORISGeneral scheduleGeneral schedule

Earth rotationEarth rotation NavigationNavigation Gravity fieldGravity fieldAccurate locationAccurate locationPrecise orbitPrecise orbit

90 91 92 93 94 95 96 97 98 99 2000 01 02 03 04

Topex-Poséidon

Envisat 1

Pleïade

Spot 2

Spot 3

Spot 4

Spot 5

Jason 1


MassMass20 kg

10 kg

DORISDORIS Instrument evolutionInstrument evolution

DORISDORIS Instrument evolutionInstrument evolution

DataData1980 200019900

1st generation, Spot 2, 3 and 4, Topex/Poseidon

No redundancy

2nd generation, Envisat

No redundancy

2nd miniaturized generation, Jason, Spot 5

No redundancy

miniaturized generation

Mass produced


DORIS PERFORMANCEDORIS PERFORMANCEDORIS PERFORMANCEDORIS PERFORMANCEGround location beacon evolutionGround location beacon evolutionGround location beacon evolutionGround location beacon evolution

MassMass

3rd generation, enhanced performance,

DateDate1980 20001990

20 kg

10 kg

0

1st generation, 50 GLBs produced

2nd generation 25 GLBs produced


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).

ConclusionsConclusionsConclusionsConclusions

Documents

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