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DARTS operational Concepts G. Harles, J. Wouters (SES ASTRA) B. Fritzsche, F. Haiduk (FHG-IIS-EAS) SpaceOps 2004, Montreal. 1A. 1E. 1D. 1F. 1G. 1C. 1H. 1B. Overview. DARTS ranging – how does it work Operational Ranging Configurations Single Station Ranging Multi Station Ranging
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DARTS operational Concepts G. Harles, J. Wouters (SES ASTRA) B. Fritzsche, F. Haiduk (FHG-IIS-EAS) SpaceOps 2004, Montreal DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
1A 1E 1D 1F 1G 1C 1H 1B Overview • DARTS ranging – how does it work • Operational Ranging Configurations • Single Station Ranging • Multi Station Ranging • Multi Station Pseudo Ranging • Multi station Pseudo ranging • Configurations, Context, Results • Residuals • Conclusion DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
DARTS ranging – how does it work (1/4) • DARTS = Digital Advanced Ranging using Transport Stream packets • Inserts ranging packets into DVB-S payload • Measures packet arrival time in uplink and downlink • Is highly accurate and reliable • Allows flexible configurations • DARTS can be used for • On-station satellite ranging • Timing and synchronization applications • Specific Features • No impact on satellite operations • Continuous and accurate measurement data • Always on system, fully automated • ASTRA Patent DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
DARTS ranging – how does it work (2/4) DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
DARTS ranging – how does it work (3/4) DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
DARTS ranging – how does it work (4/4) • Compact Device • User friendly installation and operation DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Operational Configurations (1/3) The SINGLE station tracking system • Distance and Azimuth / Elevation angle measurements are done from one single location. • Distancemeasurements can be done by • TONE Range system • Spread Spectrum Range system • DARTS Range system DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Operational Configurations (2/3) The MULTI Station tracking system • Most accurate system • Three or more range measurements from different locations • no angular measurements • accuracy depending on spatial separation and distance measurement DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Operational Configurations (3/3) The PSEUDO Range Station tracking system • Two or more range measurements, only one uplink and two or more downlinks • Accuracy depending on the spatial separation, distance measurement and synchronization DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Performance Evaluation (1/6) • Pseudo Range Configuration: • BETZDORF-SEVILLA • BETZDORF -BERGEN DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Performance Evaluation (1/6) • Pseudo Range Configuration: • BETZDORF-SEVILLA • BETZDORF -BERGEN Compared to: • Multi Station Measurements: BETZDORF-SEVILLA-BERGEN DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Performance Evaluation (1/6) • Pseudo Range Configuration: • BETZDORF-SEVILLA • BETZDORF -BERGEN Compared to: • Multi Station Measurements: BETZDORF-SEVILLA-BERGEN • Mono Station Measurements: TONE Range & AZEL Mono-pulse, BETZDORF DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Performance Evaluation (2/6) Method: • Orbit determinations using tracking data of 2 full days • The orbit determination results have been compared to a best known reference orbit using: • A full 4 STATION Trilateration system • Betzdorf • Fucino • Bergen • Sevilla • The maximum resulting errors in NORMAL, RADIAL and TANGENTIAL direction are determined over 7 days Assumption: • All systems calibrated DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Performance Evaluation (3/6) Results: DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Performance Evaluation (4/6) TONE range and AZIMUTH / ELEVATION Residuals Range residual between +5m and –5m DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Performance Evaluation (5/6) Spread Spectrum and DARTS Range Residuals Range residual between +0.5m and –0.5m DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Performance Evaluation (6/6) PSEUDO range Residuals • BTZ12/PSE#1 :Betzdorf -> Sevilla • SA#12/PSE#2 :Betzdorf -> Bergen Range residual between +8m and –8m DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Conclusions • DARTS profits from ASTRA’s heritage of experience for precise, payload based, satellite ranging systems • Device accuracy: down to 5 cm • Single Station: cost-efficient - simple operation • Multi-station: replaces mono-pulse tracking antenna, 3x better performance, 1:5 cost reduction, quick setup • Ranging and orbit determination solutions can be tailored to any operator’s needs DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Contact: Guy Harles Tel.: +352 710725 574 guy.harles@ses-astra.com Info.techcom@ses-astra.com www. ses-astra.com Thank You! DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Backup Slides: Pseudo concept Issues: Synchronisation clockA-clockB Cross device calibration (ulA)+(dlB) DARTS Operational Concepts SpaceOps 2004 May 18th, 2004
Backup Slides: Handling of Delays DARTS Operational Concepts SpaceOps 2004 May 18th, 2004