GalileoIllustration: ESAIllustration: ESA
Professor Terry Moore
Professor of Satellite Navigation
Nottingham Geospatial Institute
The University of Nottingham
© 2011 NGI
Lecture Contents
• Overview
• Services
• Satellites & Orbits
• Ground Segments (Mission, Control)
• Signals
• Status & Plans
• Institutional & financial aspects
© 2011 NGI
Global, European-led under civil control
Independent but compatible & interoperable with GPS
A variety of services are planned
GalileoEuropean Satellite Navigation System
No. of satellites 30 MEO
Constellation 3 planes, 120°
Altitude 23222 km
Inclination 56°
Ground repeat 10 days
© 2011 NGI
-Critical Infrastructure (dependence on GPS)-European independence and sovereignty-Civil controlled-A key enabling technology for EU competitiveness
Political
Social Technological
GalileoWhy do we need Galileo ?
-Transport infrastructure overload-Better & new services for citizens- Improved safety of transport- Environmental benefits
- Global market shares- Global competitiveness of all segments of the Value Chain- Employment- Efficiency of transport & other industries
-Technological lead to European industry-Not a high technological risk
Social
Economic
Technological© 2011 NGI
Galileo System Architecture
Users
Satellites
Navigation &Integrity UplinksSatellite
controlTT&C
Sensor stations
Comms Networks
Control &Processing
Centres
© 2011 NGI
User Segment
• Galileo developments includeddevelopment of a Test User Segment– to prove system function and performance
– to facilitate testing and “tweaking” of thesystem prior to declaration of operational status
• Second strand of User Segment
Users
• Second strand of User Segmentdevelopment is to support & encourage:– Receiver manufacturers
– Application developers
– And ..... End Users
• to include Galileo and its benefits in their:– Designs
– Standards
– Future operations plans
© 2011 NGI
Sensor Station (GSS)
• Globally distributed network of sensor stations
• GSS includes reference-grade Galileo receiver
• Each GSS simultaneously monitors 8-10 satellites
• Each satellite is simultaneously monitored by 8-10 GSSstationsstations
• All measurements relayed to GCC over Comms links
Sensor stations
© 2011 NGI
Control and ProcessingCentre
• Receives Satellite measurements from GSS Network
• Orbitography processing derive Orbits & Clocks
• Integrity Processing derives Integrity confirmation (& alerts)
• Relays uplink data to satellites via networks of TT&C andUplink stationsUplink stations
• Two parallel facilities at different locations in Europe forrobustness
Control &Processing
Centres
© 2011 NGI
TT&C Stations
• TT&C (Telemetry Tele-command and Control Stations trackand control satellites via uplinks
• Encryption for asset protection
• Five globally distributed stations facilitate almostcontinuous connectivitycontinuous connectivity
• TT&C interconnected to GCC by Comms network
Satellitecontrol
TT&C
© 2011 NGI
Navigation & IntegrityUplink Stations
• Smaller stations that TT&C, but more of them
• Uplink data to satellites for inclusion in Navigationdownlink– Navigation data
– Integrity
• Encryption for asset protection• Encryption for asset protection
• 12 globally distributed stations facilitate continuoussatellite connectivity
• ULS interconnected to GCC by Comms networkNavigation &
Integrity Uplinks
© 2011 NGI
Galileo’s Services© 2011 NGI
CommercialService (CS)
Galileo Services
Open Service (OS)
Search and RescueService (S&R)
Public Regulated Service (PRS)
Safety-of-LifeService (SoL)
© 2011 NGI
Services DetailsOpen Service(s)
• Market: Mass-market users, and indeed anyapplications not needing other services
• Worldwide coverage
• Free of Charge
• Performance similar to (future) GPS• Performance similar to (future) GPS
• Operable single or dual frequency
• Dual-freq accuracy: ~7m Horizontal 2D, 95%
• No integrity
• No guarantees
• Substantial effort exerted to optimise interoperabilitywith GPS
© 2011 NGI
Services DetailsCommercial Service(s)
• Market: Professional applications
• Worldwide coverage
• Performance based on OS, but ...– Enhanced accuracy, integrity, availability
• Third frequency to facilitate TCAR• Third frequency to facilitate TCAR– Triple Carrier Ambiguity Resolution
– Rapid-resolution of ambiguities for cm-level accuracy
• Encrypted data
• Potential for differentiated performance indifferent geographic areas
• (Optional) inclusion of integrity data
© 2011 NGI
Services DetailsSafety of Life Service
• Market: Safety of Life / IntegrityApplications
• Worldwide coverage
• High Accuracy, High Integrity– (see table)– (see table)
• Protected ARNS Bands
• Degraded (fallback) modeon single frequency
• Encrypted authentication TBC
• No direct charges
Horizontal accuracy 6 m (95%)
Vertical accuracy 8 m
Velocity accuracy < 0.20 m
Timing accuracy <100 ns
Continuity risk <10-5 per 150 s
Integrity Risk <3.5 10-7 per 150 s
Integrity TTA 6 s
Horizontal alarm limit 11 m
Vertical alarm limit 15 m
Availability 99.9 %
© 2011 NGI
Services DetailsPublic Regulated Service
• Market: Security services– Police, customs, critical infrastructure, military(?)
• Worldwide coverage
• Independent frequencies
• Performance similar to OS/ SoL• Performance similar to OS/ SoL
• Restricted user groups
• Controlled access
• Service robust to denial of other services
© 2011 NGI
Galileo Satellites & Orbits© 2011 NGI
No. of satellites 30 (inc.3 spares)
Constellation 3 planes, 120°
Altitude 23222 km
Inclination 56°
Ground repeat 10 days
Galileo ConstellationPlanned FOC configuration
Ground repeat 10 days
Orbital period 14:15 Hrs(5 orbits / 3 Sidereal days)
Satellites transmit continuous ranging codes & navigation data
Ground contact once per orbit for upload of S/C commanding &monitoring (S-Band)
Timing parameters, Navigation data and Integrity data up-linked continuously by dedicated ground stations (C-Band)
© 2011 NGI
Galileo and GPS
Galileo GPS
Satellites 27+3 24 (32!)
Planes 3 6
Sats per plane 10 4-7
Plane Spacing 120o 60o
Higher Galileo orbit coupled with inclination increase give bettercoverage at high latitudes
Inclination 56o 55o
Orbit type MEO Circular MEO circular
Orbit Radius 29,500km 26,500km
Period 14¼ hour 12 hour
Sat ground track repeat 10 days 1 day
© 2011 NGI
Galileo ConstellationIllustration: ESA
© 2011 NGI
Galileo SpacecraftFunctional Architecture
P a y lo a d
P o w e rS /S
S tru c tu reS /S
P o w e r I/F
S ig n a l I/F (c m d , d a ta , a n a log , ...)
Inte
gri
ty
In te g D e c
H a rn e s s n o t s h o w n
A v io n ic sS /S
(IC D S )
T T & CS /S
P ro p u ls io nS /S
D is p e n s e r,P y ro s
S /S
R a n g in gS /S
T h e rm a lS /S
U m b . P o w e r
D e c /E n c
TC
/Nav
TM
Inte
gri
ty
S ta tu s
L a u n c h e r I/F
P y ro C m d
U m b ilic a lP o w e r
S ta tus &© 2011 NGI
Galileo PayloadFunctional Breakdown
• Reference Clock generation
• Generative payload providing L-Band navigationservices– Reception & storage of up-linked Navigation and Integrity data
– Security on Mission data uplink and PRS signal– Security on Mission data uplink and PRS signal
– Generation of ranging codes
– Assembly of navigation message in the defined format
– Broadcast of navigation signals at the defined frequencies andpowers
• Search and Rescue Transparent Transponder
• Control and Monitoring of Payload, and interface to thePlatform
© 2011 NGI
Galileo PayloadFunctional Breakdown
© 2011 NGI
Galileo Ground Segments:
- Mission (GMS)- Control (GCS)- Control (GCS)© 2011 NGI
Ground Mission SegmentOrbit Determination and TimeSynchronisation System (ODTS)
• Globally distributed network of monitoring stations
• Measure pseudo-ranges using code & phase tracking
• Each station can monitor up to 12 satellites in parallel
• A minimum of 3 monitoring stations, with accurately knownlocations, are needed to fix the satellite position, 4 forposition and clock (satellite) corrections.position and clock (satellite) corrections.
• Measurements are pre-processed and sent to a processingcentre where the ephemeris (orbital position) and clockcorrections are computed
• Ephemeris and clock corrections are uplinked to thesatellites via a network of uplink stations
© 2011 NGI
Ground Mission SegmentODTS Architecture
Rubidium andPassive H-maser
clocks
ULS
GSSAtomic clockdata
PTS (x2)4 Caesium clocks
2 H-maser
UTC(k) laboratory
Timesteeringto UTC
ODTS
Ephemeris& ClockPrediction
GSTdefinition
OSPF
ULS© 2011 NGI
Main Steps in ODTS
1. Orbit prediction by numerical integration of the equations ofmotion over a given time
2. Computed tracking observations constructed numerically fromknown station position and the satellite positions fromintegrated orbit
3. Differences are computed between the tracking observationsand the calculated values from the orbital model. –and the calculated values from the orbital model. –measurement residuals
4. Least squares estimation of corrections to various modelparameters
5. Entire process iterated until the desired level of precision isreached
ODTS processing
One-waymeasurements
Met data
Dynamicalmodels Ephemeris
prediction andclock correction
© 2011 NGI
Ground Mission SegmentGalileo Integrity
• The Galileo Ground System monitors Galileo Satellitetransmissions for Integrity
• If any out of tolerance conditions are detected, theGalileo System alerts users of the Integrity problem
• The alerting mechanism uses the normal (SoL)• The alerting mechanism uses the normal (SoL)navigation transmissions to communicate to users– Galileo SIS include Integrity confirmation & Integrity Alerts
• Alerting has to be done within a defined time to alert(TTA) limit
© 2011 NGI
All Satellites
• Set satellite Health Flags• Incorporate SISA and satellite
Health Flags into navigationsignals
Selected DisseminatingSatellites
• Collect Integrity Messages• Incorporate Integrity Messages
into Navigation signals
Ground Mission SegmentGalileo Integrity
ODTS
• Compute SISA• Upload SISA
IDS
• Validate Satellite Health Flags• Perform SISA Independent Check• Compose Integrity Message• Upload Integrity Message
C-band Nav.U/L Nav. D/L signals C-band Integrity U/L© 2011 NGI
Ground Mission SegmentGalileo Integrity
GCC
GSSIntegrity Data
IPF
ULS
© 2011 NGI
Integrity Principles
• Observe every satellite with a sufficient number ofmonitoring stations
• Pre-process the measurements for– troposphere propagation
– ionosphere propagation
– multi-path detection– multi-path detection
• Exclude monitoring stations with high multi-path,troposphere or ionosphere activity on a per satellite basis
• Flag satellites as bad, for which the difference between thecomputed and corrected measured pseudo-range is ofstatistical relevance for at least one monitoring station.
• Uplink the integrity message to the satellites forincorporation into navigation message
© 2011 NGI
Partitioning of IntegrityBetween System and User
• System provides timely warning if the errors caused by
– Satellite
– Clock
– Signal
– Navigation message
… are larger than threshold value… are larger than threshold value
• User has to assess all the hazards on the
– signal propagation path and
– all local effects
… by using redundant signals & signal quality measures(e.g. using Receiver Autonomous Integrity Monitoring)
© 2011 NGI
Galileo Ground ControlSegment (GCS)
• The GCS provides for all classical satellite controlTelemetry, Tracking and Commanding (TT&C)functions of the 30 MEO satellite constellation
• Functions are implemented via a Satellite ControlFacility (SCF) located at a Galileo Control CentreFacility (SCF) located at a Galileo Control Centre(GCC) distributing and receiving data to theconstellation of satellites via 5 globally distributedTT&C stations
• Data communication with these remote TT&C stationsfrom the SCF is via a dedicated Data DistributionNetwork
© 2011 NGI
GCS Architecture
GCC
SCCF
TT&C TT&C
Etc.
comms comms
© 2011 NGI
Galileo Ground SegmentRationale for Site Locations
• Geographical locations based upon European or friendly nationterritories utilising existing facilities with communications networks
• Galileo Sensor Stations (29+)– These are receiving stations for reception of the 4 L-Band signals
– The number of these stations has been defined according to the needs ofIntegrity and ODTS
• TT&C stations (5)• TT&C stations (5)– Five global locations required to provide routine TM&TC operation and to enable
near constant contact with the constellation in case of emergencies
• Mission uplink stations (Navigation & integrity) (10)– Locations defined to ensure up-link of integrity to a subset of S/Cs visible by
users with a masking angle >25°
– Navigation uplink required every 100 minutes to all satellites for clockcorrections
– Continuous uplink of Integrity data
© 2011 NGI
GalileoOverall Ground Architecture
MCF
(IMC)
GCC-1 (GCC-2)
5 S-band TT&C sites(13m dish, 1 dish per site)
co-located with 5 GSS and5 C-band U/L stations
Geo
gra
ph
icallin
k
19 Galileo Sensor Station (29 total)3 RX chains per GSS (NAV + INT + Backup)
DOC5 + redundancy
SCF
(IMC)
PTF
IPF
OSPFSPFGACF
5 C-band U/L stations (10 total)(3.0m dishes, 4 dishes per site)
co-located with 5 GSS
EXTERNAL INTERFACES
Geo
gra
ph
icallin
kLAN
LAN
© 2011 NGI
GalileoGround Segment Sites
Kiruna
Svalbard
Redu
Fucino
StPierre&M.
Az/CanUSNO
Hawaii Riyadh
S.Korea
Wainwright
GSS
GSS + ULS
GSS + ULS + TTC
KourouUnder FOC procurement
FOC contract awarded
Papeete
Réunion
IOV contracts/ATP
Troll
Noumea
Ascencion
Kerguelen
Cordoba South Africa
Hawaii Riyadh
Easter IslandPerthHartebeesthoek
Note: other potential sites are under consideration for FOC, incl. Falklands,Terre Adélie, Jan Mayen, Reykjavik, Diego Garcia, Guam
© 2011 NGI
GalileoIOV Ground Segment Sites
Kiruna Galileo TTC Site Completed (Nov 2007)Kiruna Galileo TTC Site Completed (Nov 2007)
Svalbard Galileo ULS/GSS Site Completed (May 2008)
© 2011 NGI
GalileoGround Control Centres
OberpfaffenhofenCredits:
Fucino(Italy)
Oberpfaffenhofen(Germany)
Credits:ESA
Credits:ESA
Credits:ESA
© 2011 NGI
Galileo Signals© 2011 NGI
GNSS-Frequency Bands
GPS GLONASS
1240 12561260 1300 MHz
E6
12171164 1188
E5BL5 L2 G2
GALILEOGALILEOGPS/ GALILEO
E5A
E1E2 G1L1 C1
GPS/ GALILEO GLONASS
1563 15871593
1610 MHz1559
G1L1
5030 MHz5000 5010
Uplink
406.0-406.1MHz
DistressUplink
1544.05-1544.15MHz
SAR-Fwd-downlink
GALILEO - SAR
E6-(A): -155dBW
E6-(B): -158dBW
E6-(C): -158dBW
L1(A): -155dBW
L1(B): -158dBW
L1(C): -158dBW
E5a-I: -158dBW E5b-I: -158 dBW
E5a-Q: -158dBW E5b-Q:-158 dBW
On-Ground Galileo Power
© 2011 NGI
Galileo Signals
© 2011 NGI
Impacts of GalileoSignal Design
• Improved acquisition & tracking
• Improved multipath performance
• Improved building penetration
• Through implementation of various signal features:– Wider bandwidths
– More frequencies
– Improved BOC modulation schemes
– High chip rate
– Improved codes
– Pilot tone
• And dual (multiple) civil frequencies permitting mitigationof ionospheric uncertainty & supporting CP Ambiguityresolution
© 2011 NGI
Galileo Status & Plans© 2011 NGI
Galileo Timescale
© 2011 NGI
GalileoImplementation Steps
In-Orbit Validation4 IOV satellites plus ground segment
Initial Operational CapabilityEarly Services for OS, SAR, PRS
18 satellites
2014
Full Operational CapabilityAll services, 30 satellites
2019/2020
Galileo System Testbed v1Validation of critical algorithms
2003
Galileo System Testbed v22 initial test satellites
2005
2012© 2011 NGI
Galileo Development & Test
• Concept, Mission Definition, System, Subsystem andElement Studies, Specifications, Design,Developments, Test, Validation, Verification– ~1999 -> ~2011
– Completed– Completed
• GSTBV1 – Galileo System Testbed v1– Validation of critical algorithms
(included use of GPS measurements!)
– Completed 2004
• GSTBV2 – Galileo System Testbed v2– Initial Galileo satellites (also called GIOVE)
• A - launched Dec.2005 (still operating)
• B - launched April 2008 (still operating)
© 2011 NGI
GSTB-V2 / A Giove-A GSTB-V2 / B Giove-B
Galileo System Test BedSatellites
• Lift-off mass 450 kg
• Power demand 600 W
• Stowed Dimensions1.3 m x 1.74 m x 1.4 m
• Lift-off mass 523 kg
• Power demand 943 W
• Stowed Dimensions:0.955 m x 0.955 m x 2.4 m
© 2011 NGI
Galileo IOV
• Full-scale hardware & software development and deploymentleading to qualification of Space, Ground & User segments
• Limited constellation (4 satellites)
– First 2 satellites scheduled to be launched from Kourou (FrenchGuiana) 20 October 2011
– Next 2 IOV satellites for launch 2012
• Limited capability Ground Segment largely deployed and• Limited capability Ground Segment largely deployed andcommissioned
– Two Ground Control Centres (GCC) working in ‘Split GCC’ mode
• Fucino (Italy) GCC – host and operate the GMS (Mission Segment)
• Oberpfaffenhofen (Germany) GCC – host and operate the GCS (ControlSegment)
– A network of sensor stations providing coverage for orbitography andsynchronisation measurements
– A network of uplink stations providing uplink of the navigation data
– Two TT&C stations providing control of the constellation
– A global data dissemination network to interconnect the groundfacilities
© 2011 NGI
Galileo IOV Satellites
• Galileo IOV Satellites– Galileo final design Satellites
• Payload includes– complete & final navigation chain
• generation and broadcast of various• generation and broadcast of variousGalileo in L-band navigation signals
– Clocks
• 2 rubidium atomicclocks
• 2 passive hydrogenmasers
• Mass Approx. 700 kg
• Size (1) 3.02 x 1.58 x 1.59 m
• Size (2) 2.74 x 14.5 x 1.59 m
• Design lifetime 12 years +
• Available power 1.420 W (sunlight)
/1.355 W (eclipse)
• Nav P/L power 780 W
• SAR P/L power 100 W
(1) solar array stowed; (2) solar array deployed
IOV Satellite (Image: ESA)© 2011 NGI
GalileoInitial Operational Capability (IOC)
• Satellites (final design)
– Contract awarded for 14 satellites to new supplier – OHB
• IOV phase satellite from EADS Astrium
– Leads to constellation of 18 satellites in 2013/14
• 14 IOCs + 4 IOVs
• Enhanced ground segment (c.f. IOV)• Enhanced ground segment (c.f. IOV)
– More stations, more robust, more capabilities
– Ground Segment GMS contract awarded to Thales Alenia Space
– Ground Segment GCS contracts awared to EADS Astrium
• Increased, but incomplete services
– OS: Yes
– PRS: Partial
– SoL: TBA
– Commercial: Beta test
© 2011 NGI
GalileoFull Operational Capability
• Completion of Satellite constellation– Another 12 Satellites (incl. 3 spares; replacements TBA)
• Full ground infrastructure– Full functionality
– Full robustness and redundancy
• Full Services (probably)• Full Services (probably)
– Political debate continues• Could affect PRS and/or SoL Services
• Requires a further €1.9B– Proposed to come from established EC budgets
– ... but another Galileo political fight still likely!
• Schedule
– Start: soon!
– Completion: 2019/20
© 2011 NGI
Institutional andFinancial Aspects of Galileo© 2011 NGI
Galileo ProgrammeDecision Making & Control
Political Decision Making
and Oversight
Management andExecution
European GNSSProgr Committee
MemberStates
EC
Fully Responsible forOverall ProgrammeManagement asEuropean GNSS
PoliticalProgramOversight
EUParliament
Budgetary Authority &Ultimate Decision-Making Bodies
for the GNSS Programmes (Galileo and EGNOS)
EUCouncil
ESA GSA
European GNSSProgramme Manager
ProcurementAgency
Technical Certification,Security Accreditation,
Market Preparation& Commercialisation
Independent ProjectMgt Expert Team
© 2011 NGI
Galileo FOC Procurement
ESASystem Prime & Procurement Agent
System Support
WP1
ECProgramme Management
DelegationAgreement
System Support
SpaceSegment
GroundControl
Segment
GroundMission
Segment
Launcher Operations
WP6WP5WP4WP3WP2
Time Services
GeodeticServices
SAR InitialServices
Site Hosting© 2011 NGI
Galileo FOC Procurement
Work Package Winner / Shortlisted
1. System Support ThalesAleniaSpace (Italy)
2. Ground Mission Segment ThalesAleniaSpace (France)
3. Ground Control Segment EADS Astrium (UK)
4. Space Segment
Work Order 1: OHB System (Germany)
Candidates for subsequent work orders:
• OHB System (Germany)
• EADS-Astrium Germany)
5. Launch Services Arianespace (France)
6. Operations OPAL (Germany+Italy)
© 2011 NGI
Estimated CostsBuild & Launch of Galileo
Item Cost in Euro
Phase 1 Definition (complete) €0.133 billion
Phase 2 Development and validation (under way) €1.502 billion
Phase 3 Deployment to IOC €3.405 billion
EGNOS costs to date included in Galileo Budged €0.520 billion
Funding for Galileo-related research Frameworkprogrammes FP5 – FP7
€0.48 billion
Estimated total build and launch costs €6.04 billion
Deployment of full FOC €1.9 billion
Operations Phase ( cost over 20 years – not commenced) €7.96 billion
TOTAL
Estimated build, launch, & running costs 25 years
€15.9 billion
© 2011 NGI
Galileo IOCCost Breakdown (M€)
Galileo IOCSatellites + launchers 1,600Ground System infrastructure 400Operations 275Systems Engineering 150Systems Engineering 150Procurement Agent management costs 195
EGNOS Exploitation & Ops (2008–13) 330
Support to the CommissionProject management & advisory services 27
Contingencies 428
Grand Total 3,405
Source: European Commission
© 2011 NGI
GPS / GalileoInteroperability
• Extensive EU/US negotiations at political and technicallevel over many years
• Signal interoperability:– (a) Interoperable Signals
• Future receivers using MBOC can track GPS & Galileo signals• Future receivers using MBOC can track GPS & Galileo signals
• Benefits of multiple GNSS constellations – greater signalavailability and coverage worldwide
• Higher accuracy in challenging environments
– (b) Non-Overlapping Compatible Signals
• (Military) desire to be able to remove one signal (X) withoutdisrupting another (Y)
• A point of contention since desire of the one military of one statemay not overlap with desire in another state!
© 2011 NGI
• Timescales– GPS & Galileo systems broadcast the difference between their
respective system times (GPST / GST) and Universal Time(UTC)
– Performance specified (maximum deviation, etc.)
– Can be solved in receiver by instigating “extra” unknown
GPS / GalileoInteroperability
– Can be solved in receiver by instigating “extra” unknown
– i.e. x, y, z, dT(GPS), dT(Galileo)
• Datums– GPS: WGS84, Galileo: GTRF, GLONASS: PZ90; etc.)
– Implement algorithmic correction in receiver to changecoordinates
© 2011 NGI
Summary
• Galileo Overview
• Services from Galileo
• Satellites & Orbits
• Ground Segments (Mission, Control)• Ground Segments (Mission, Control)
• Galileo Signals
• Status & Plans
• Institutional & financial aspects
© 2011 NGI
Contact Details
Professor Terry Moore
Director of the NGI
Nottingham Geospatial Building
The University of Nottingham
Triumph RoadTriumph Road
Nottingham
NG7 2TU
Telephone: +44 (0) 115 951 3886
Fax: +44 (0) 115 951 3881
Email: [email protected]
WWW: www.nottingham.ac.uk
© 2011 NGI