The Galileo Ground Mission Segment Performances

1. The Galileo Ground Mission Segment Performances Francisco Amarillo-Fernandez, Massimo Crisci, Alexandre Ballereau John Dow, Martin Hollreiser, Joerg Hahn, Jean-Luc Gerner, European Space Agency

2. CONTEXT • Presented performance: • Refer to the Galileo Mission Segment (range domain) • Are the result of the Segment Critical Design Review (CDR) experimentation process • Are derived from an experimental platform hosting replicas of the operational algorithms for both the Navigation and Integrity Functions • Are derived in synthetic scenarios based on conservative assumptions • Are confirmed in real scenarios for the Navigation Function

3. Introduction (I). Galileo Ground Mission Segment. Functional Overview • Determines and uplinks the navigation data for each Galileo satellite: • Orbit description, via 15 orbital parameters • OS on-board clock description, via 3 parameters • SoL on-board clock description, via 3 parameters • TEC global model input parameters • Differential group delay between the two OS pilot signals • Differential group delay between the two SoL pilot signals • Galileo to GPS time offset • SoL Signal-In-Space- Accuracy (SISA) • Determines and uplinks the integrity data for the Galileo constellation: • Integrity table including the Signal-In-Space-Monitoring-Accuracy (SISMA) • Integrity alarms

4. Introduction (II). Definitions • Signal-in-Space Accuracy (SISA) “SISA is a prediction of the minimum standard deviation (1-sigma) of the unbiased Gaussian distribution which overbounds the signal-in-space error (SISE) predictable distribution for all possible user locations within the satellite coverage area” • Signal-in-Space Monitoring Accuracy (SISMA) “SISMA shall be a prediction of the minimum standard deviation (1-sigma) of the unbiased Gaussian distribution which overbounds the error of the estimation of SISE as determined by the integrity monitoring system”

5. Part I. Tracking Stations Performance

6. Part II. Orbit & Clock Determination Performance

7. Part II (continuation-I) Ranging accuracy (95%) versus satellite and experimentation batch DAY

8. Part II (continuation-III) Part III. GTTO Offset Determination Performance

9. Part IV. Group Delay Determination Performance

10. Part V. Integrity Determination Performance

11. Part V. (continuation-II) Real-Time Monitoring accuracy (68%) vs satellite footprint. Degraded

12. Part VI. Conclusions • Exhaustive performance analysis have been carried out on all the Ground Mission Segment (GMS) key performance figures • The GMS key algorithms typical performance expectations surpass generally the initial performance expectations • At this stage it is considered likely that the performance of the GMS Navigation Determination/Integrity Determination Functions will be overall compatible with the system availability needs • The GMS Navigation Determination Function & especially the GMS Integrity Determination Function algorithms will provide level of performance which had never been achieved before by any existing core GNSS System

13. Part VII. Additional Considerations • Improvements, which are not required to satisfy the System requirements, are possible. ESA is already working hard on the preparation of the technology for “Galileo+” . • Nevertheless the performances evaluation cannot be entirely conclusive at this stage, besides the fact of the enormous sophistication of the evaluation process, due to limitations on a number of key physical and engineering models. Re-evaluation is required and of course planned at IOV

14. Email: Francisco.Amarillo.Fernandez@esa.int Telephone: +31 71 565 3446 THANK YOU