ESA’s GSTB Programme

• GSTB-V1 is a ground system to test Galileo’s key algorithms using GPS data

• GSTB-V2 consists of a pair of satellites:

– GSTB-V2/A (SSTL) – now known as Giove-A launched in December 2005

– GSTB-V2/B (Galileo Industries) backup satellite in case of launch failures etc. Due to be launched in April 2006.

• GSTB-V2 contract worth £20M awarded to SSTL in July 2003

Giove-A Platform

• Platform– Dimensions: 1.3m x 1.3m x 1.4m

(stowed)

– Wet mass: 660kg

– Power generation: Sun tracking arrays

– Sensors: EHS, ASS, Gyro

– Actuators: Wheels, Magnetorquers, Thrusters

– Pointing: ±0.55° pitch/roll required (3), ±0.1° achieved; ±2.1° yaw required, ±1.0° achieved

– Orbit determination: NORAD, Laser ranging, GPS, reverse GNSS

– Propulsion: 90 ms-1 v butane system

– TT&C: S-Band

– Avionics: SSTL Enhanced Microsat

Giove-A Navigation Payload

• Custom payload designed by SSTL

• Payload items supplied by ESA through contracts with third parties:

– Alcatel Espacio (Spain) – Clock Monitoring & Control Unit

– Norspace (Norway) – Frequency Generation & Upconvertor Unit

– Alenia (Italy) – Wide-band Radiating Antenna System

– Laben (Italy) – Navigation Signal Generation Unit

– Temex (Switzerland) – Rubidium Atomic Frequency Standard (stable to 10 ns per day)

Giove-A Environmental Payloads

• MERLIN – QinetiQ– Cosmic-Ray LET Spectra

– Proton Flux

– Total Ionising Dose

– Electrons/ Deep Charging Currents

• CEDEX – UniS/SSTL– Cosmic-Ray LET Spectra

– Proton Flux

– Dose-Rate Induced Photocurrents

Proton fluxHeavy ion LETspectrum

Total dose B

Total dose AElectrons &deep charging

MerlinSpace Weather Monitor

CEDEXSpace Weather Monitor

Giove-A Experimental Payloads

• GPS Receiver – SSTL

• Laser Retro-Reflector

Laser Retro-Reflector Array

SSTL Miniature Space GPS Receiver

CEDEX Radiation Monitor

MERLIN Radiation Monitor

GPS Receiver Antenna

Giove-A Payload Architecture

AleniaAntenna

Upperband

Lowerband

CEDEX MERLIN

Payload RF Section TM/TCnode

SatellitePlatform

Tx0Tx1

Rx0Rx1

CAN

CAN CAN

CAN

Payload RF Section TM/TCnode

CAN

MEO GPSReceiver

LaserRetro-reflector

CAN

CFI

Environmental payload

Experimental payload

SSTLNSGU Interface

CAN

1553

Alcatel EspacioClock Monitoring &

Control Unit(CMCU)

TM/TC B

10.23MHz 10MHz 10MHz

TM/TC A

TEMEXRubidium Atomic

Frequency Standard(RAFS)

TM/TC A

10MHz

TEMEXRubidium Atomic

Frequency Standard(RAFS)

TM/TC B

10MHz

SSTLNavigation Message

Generation Unit(NMGU)

CAN 1553

SSTL Modulator,Frequency Generator &

Upconverter Unit(MFUU)

CAN 10.23MHz

Dupper

Dlower

E5a,b

E6

E2L1E1

E5a,b E6 E2L1E1

CA

MP

1C

AM

P210.23MHz

DigitalClock

Splitter

SSTLCFI Interface B

CAN

TM/TC

SSTLCFI Interface A

SSTLCFI Interface A

CAN

TM/TC

TW

TA

TW

TA

Coupler

CouplerDiplexer

E2L1E1

E5a/b

E6

LabenNavigation SignalGeneration Unit

(NSGU)

1553 1553 TM/TC B

122.76MHz

TM/TC A

NorspaceFrequency Generation& Upconversion Unit

(FGUU)

TM/TC B

122.76MHz

10.23MHz

TM/TC A

• Payloads: Navigation, Environmental and Experimental

Giove-A AIT

Antenna

Payload Bay

Avionics Bay

Propulsion Bay

Giove-A Flight Model 1st Integration at the Surrey Space Centre, University of Surrey, Summer 2005

Launch!

• Launch Day: 28th December 2005 05:19 UTC• Soyuz launch vehicle from Baikonur• Fregat upper stage to inject Giove-A into the correct Galileo

orbit

LEOP

• Communications were established with the SSTL ground-station at the University of Surrey immediately upon separation.

• Telemetry received at Surrey, Bangalore, India and Kuala Lumpur, Malaysia, in conjunction with the 12m satellite tracking antenna at RAL, showed all systems were nominal.

• The solar arrays deployed perfectly, and initial operations were completed ahead of schedule.

First Navigation Signals

• Europe’s first Galileo navigation signals were transmitted by Giove-A at 17:25 UTC on 12th January 2006.

• The signals were commanded on from Surrey and the Galileo signals were received by the 25m antenna at the CCLRC Chilbolton Observatory, Andover, UK and the ESA Earth-Station in Redu, Belgium

• The Galileo E5 and L1 channel signals were successfully decoded by a Galileo Navigation Receiver at Surrey...

Conclusions

• In July 2003 SSTL embarked on its most complex project ever – the design and construction of a totally new 600kg+ satellite for use in Medium Earth Orbit.

• Surrey rose to the challenge and, just 24 months later, delivered the Giove-A satellite to ESA for environmental testing.

• The Soyuz launch from Baikonur was successful, and platform commissioning was completed ahead of schedule.

• On 12th January 2006, Giove-A met its prime objective of demonstrating a Galileo navigation signal in space.

• Giove-A already has been a remarkable success, and it will enable ESA to achieve their 4 major objectives with this satellite at relatively low cost.

• The Galileo system is on its way!