Giove Workshop 131008 12

GALILEO Performance Validation with GIOVE J. Hahn / S. Binda Galileo Project Office

1

Risk Mitigation What does “Risk Mitigation” mean? 1. Validate key assumptions taken during the design phase using real in-orbit measurements 2. Validate space and ground H/W pre-developments and feedback manufacturers to take results into account in the System Preliminary CDR of the IOV phase 3. Take into account lessons learnt in the FOC ITT preparation

2

Risk Mitigation: 1. Design Assumptions • Galileo Signal In Space design is on track as confirmed by measurements on the field • On board clock performance specification appears feasible and with margin (quiet conditions) • Sensor station tracking error specification for Galileo Sensor Stations is confirmed • Corresponding models extracted from GIOVE data have been provided to GMS for Raw Data Generator validation • System Performance Budget File will be updated accordingly

3

System Performance Status Service Level Status (@ S-PCDR KO) Development Status - S-PCDR

GSRD OS Positioning Accuracy SOL

H V H V

PRS

SF_E5/6

SF_L1

DF

E5a

E5b

L1

E5a-L1

SOL E5b-L1

E6

PRS L1

E6-L1

24m 35m 24m 35m

15m 35m 15m 35m

4m 8m 6.5m 12m

30m 55m ---

29m 51m ---

16m 38m ---

4m 5m ---

4m 5m ---

--29m 42m

--16m 36m

--4m 6m

13cm/s

13cm/s

Velocity Accuracy 3D

20cm/s

Availability of Accuracy nom comb WUL

100% 99.5%

28.7cm/s 100% 99.5%

23.1cm/s

20.3cm/s

100% 99.5%

100% 99.5%

GMS CDR results not yet included (ongoing)

GIOVE MRD 100% 99.5%

100% 99.5%

Integrity SOL PRS Risk SOL PRS

HAL VAL HAL VAL TTA TTA

--------

--------

12m 20m 20m 35m 2e-7 6s 10s

--------

--

--

8e-6

--

Continuity Risk Availability of Int & Cont nom comb

100% 99.5% at WUL

--------

--------

1m--SISA -GMS CDR -Status --

--------

12m 20m --2e-7 6s --

--20m 35m 2e-7 -10.1s

12m 20m --2e-7 6s --

40m 20m --2e-7 6s --

--

8e-6

8e-6

8e-6

8e-6

100% 99.4%

100% 99.7%

-99.5%

w-w

w-w

99.3% 98.3%

---

Coverage world-wide

world-wide Compliant

w-w Partial-Compliant

world-wide Non-Compliant

4

Link to Segment Drivers

Equip. Level

Design

GIOVE: 45cm**

SOC SOC GSRD

Development Status - S-PCDR OS

Positioning Accuracy SOL

H V H V

PRS

SF_E5/6

SF_L1

DF

E5a

E5b

L1

E5a-L1

SOL E5b-L1

E6

PRS L1

E6-L1

24m 35m 24m 35m

15m 35m 15m 35m

4m 8m 6.5m 12m

30m 55m ---

29m 51m ---

16m 38m ---

4m 5m ---

4m 5m ---

--29m 42m

--16m 36m

--4m 6m

13cm/s

13cm/s

38 cm*

Velocity Accuracy 3D

20cm/s

Availability of Accuracy nom comb WUL

100% 99.5%

28.7cm/s 100% 99.5%

23.1cm/s

20.3cm/s

100% 99.5%

100% 99.5%

Status

Integrity SOL PRS Risk SOL PRS

HAL VAL HAL VAL TTA TTA

--------

--------

12m 20m 20m 35m 2e-7 6s 10s

--------

--------

--------

--------

12m 20m --2e-7 6s --

--20m 35m 2e-7 -10.1s

--

--

8e-6

--

--

--

--

8e-6

8e-6

Continuity Risk Availability of Int & Cont nom comb

100% 99.5% at WUL

---

99.3% 98.3%

---

100 cm* 100 cm* 90 %

Equip. Level

10 %

100% 99.4%

Coverage world-wide

world-wide Compliant

w-w Partial-Compliant

world-wide Non-Compliant

*GMS-CDR Development Status **GIOVE exp. confirmation

5

GIOVE perspective on Galileo performance drivers

Requirement

Galileo

GIOVE

Comment

Ranging Accuracy (95 %)

1.3 m

0.9 m (0.45 m, 1-σ)

GIOVE: Orbit and Clock Prediction (33 cm / 2.0 ns, 1σ)

GSS Code Phase error

0.81-0.21 m

0.83-0.35

PC at elev. > 40deg

GSS Carrier Phase error

10 mm

2 mm

Single Frequency Ionospheric Algorithm

30% or 20TECU

<16TECU

GGTO Offset

5.0 ns (2 sigma) (86400s)

4.5 ns

SV Differential Group Delay stability of ranging signals

0.3ns / 24h (payload spec only)

0.4ns / 24h (overall process performance)

Galileo: TWSTFT GIOVE: broadcast nav msg

Note: strict requirement comparison is NOT possible.

6

GIOVE perspective on Galileo performance drivers

Requirement

Galileo

GIOVE

Comment

RAFS freq. drift

1e-12/day

1.8e-12/day

GIOVE: worst case - typical value 1e12/day

RAFS freq. stab.

1s: 5.1e-12 10s: 1.64e-12 100s: 5.1e-13 1000s: 1.64e-13 10000s: 5.1e-14

300s: 2e-13 1000s: 1.5e-13 10000s: 9e-14

PHM freq. drift

8.2e-15/day

1e-14/day

PHM freq. stab.

1s: 1.1e-12 10s: 3.5e-13 100s: 1.1e-13 1000s: 3.5e-14 10000s: 1.1e-14

300s: 2e-13 1000s: 9e-13 10000s: 3.5e-14

…

…

…

C if drift removed Frequency trend after switch-on typical of the Rb technology

Not in Galileo spec but still two order of magnitude better than RAFS PC due mostly to measurement system noise

…

Note: strict requirement comparison is NOT possible.

7

Key Driver Traceability Driver

Spec

Equipment level

Verification Status

Design Status

Microsoft Excel Worksheet

DOORS

8

Risk Mitigation: 2. Pre-developments H/W

Space H/W Predevelopments: • More than two years operation in orbit has allowed full characterisation of the RF chain • Frequency standards behaviour in orbit characterised and lesson learnt put in place in IOV spacecraft Ground H/W Predevelopments: • Antenna’s multipath rejection and group delay variation lesson learnt put in place • Test User Receivers in-field measurements have allowed to improve Front End capabilities

9

Experimentation Results and Roadmap Experimentation Results: • GIOVE-A from May 2007 to July 2008 • GIOVE-B from P/L switch-on 7 GPS to GST May 2008 to July 2008 Offset OSPF 2 Roadmap: 3 Satellite Clock Sensor Station • GIOVE-A Characterization 1 Characterization (March 2009) RAFS/PHM, Navigation Algo’s Assessment GSS and GRC • GIOVE-B CMCU, OSPF OSPF (July 2010) 5 Iono + BGD OSPF

6 Calibration + Validation

4 Orbit Models OSPF

GSS, OSPF, GGSP 10

ODTS & IONO Experimentation Orbit Determination & Time Synchronisation experimentation: • Detailed ODTS pre-processing robustness analysis (cycle slips, code smoothing) • ODTS performance vs observable combination (L1C-E5b and L1C-E6C has been used) • IONO: evaluation of NeQuick model v1, Single Frequency Iono algo, disturbance flags, and extension of inter-frequency bias analysis to other code combinations (L1C-E5b and L1C-E6C analysed) • Comparison of L-band-only with SLR-only orbit for calibration purposes (a dense SLR campaign is needed) Roadmap • ODTS: preprocessing of existing Antenna effects (elevation dependant GD and phase centre variations), SV manoeuvres handling • Orbit models: alternative solar radiation parameters models, performance over eclipses • IONO: evaluation of NeQuick v2 model, disturbance flag refinement, and consolidation of inter-frequency and inter-system bias analysis • Comparison of L-band-only with SLR-only orbit for calibration purposes (e.g. better determination of SV/GESS IFB) 11

On-Board Clock Experimentation On Board Clock Characterization experimentation: • Definition and testing of an operational clock initialization procedure, involving GSCs, both for GIOVE-A and -B • Accurate evaluation of stability (short, medium, long term) based on a long period of observation done for GIOVE-A • Stability and suitability of the H maser ground reference clock as external time reference to a GESS (GIEN and GUSN master clocks) • Effects of Radiation on clocks investigated Roadmap • Accurate evaluation of stability (short, medium, long term) based on a long period of observation of the PHM • Stability and suitability of the H maser ground reference clock as external time reference to ESTEC GESS • Deliver Time Deviation estimates • Confirm using experimental data the impact of relativistic effects • Use onboard RAFS-PHM phase to routinely steer the RAFS • Confirm Radiation effects on GIOVE-B using SREM 12

Sensor Stations Characterisation Sensor Station Characterization experimentation: • Assessment of PRS (L1A and E6A) partially done • Exploit diversity of sensor stations sites, building correlation between : 9 Site environment as assessed in the site survey reports 9 Station output data quality performances • Synthesis activities, including in particular : 9 Building Galileo Sensor Station models 9 Full consolidated comparison between GPS and GALILEO 9 Final extrapolation to Galileo Roadmap • GIOVE-A vs GIOVE-B sensor station error budget • Consolidation of Sensor Station Error Budget including new receivers (OS/CS and SoL GSS like) • Consolidation of comparison between BOC/CBOC/TMBOC • Characterisation pulse blanking effectiveness • Specific analysis on the impact of the ionospheric scintillation on the receiver performance • Consolidate the impact of GMS preprocessing on tracking performance • Complete assessment of PRS (L1A and E6A) 13

Navigation Msg Broadcast Navigation Message generation and Broadcast: • Routine ODTS execution for navigation message uplink implemented, evaluation of robustness and operational aspects partially done • GIOVE-A EGGTO from the GPS/Galileo Navigation message + Orbit Determination & Time Synchronisation (using GPS/GALILEO receivers only) is the baseline Roadmap • Consolidate navigation message uplink for GIOVE-B (including “real time” clock and orbit assessment), and evaluation of robustness and operational aspects (data latency, execution time) through the Key Performance Indicators • Inclusion of GGTO in GIOVE-B • Experimental GST - UTC prediction in navigation message 14

Bi-lateral Cooperations Areas of cooperation with external entities/institutes: • Diversify Galileo Experimental Sensor Stations (improved version including upgraded computer NovAtel RX and TAS-I RX based on IOV GSS) • User base increased to around 60 people from industrial/academic organisation • Application from Portugal, Canada, Poland for the attachment of GESS received Roadmap • Increase the number of GESS stations • Increase the number of data user • Share GESS data and cross-validate experimental Core Products 15

Validation is an incremental process

2003

GPS Constellation

GSTB V1

2005

Giove Satellites

GSTB V2

2010

Galileo In Orbit Validation

IOV Phase

2010-2013

Galileo Full Operation Const.

FOC Phase

16