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2008-08-15 OPS-G Forum

Boris Smeds OPS-GSY

The new ESTRACK Santa Maria Ground station for support of

Ariane 5 launch of ATV.

Head of Systems and Project Support Section

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

The Santa Maria Station is presented by:

Part 1 Boris Smeds OPS-GSY

Overview of requirements and technical implementation Specific differences compared to a conventional satellite

ground station Lessons learned, unexpected problems and how they

were solved

Part 2 Gerhard Billig OPS-ONV

Test and validation Operational concept, preparations and launch operation

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Requirements Receive telemetry data from Ariane 5 during the launch of ATV and send to

Kourou in real time.

Cover the passes over the Atlantic region.

Santa Maria Azores

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Time scale of actual implementation. April 2006: Site Inspection

June 2006: SoW for antenna and related equipment. ITT

September 2006: PDR for antenna, TM system and power plant

November 2006: CDR for antenna and TM system

March 2007: Start of Factory Acceptance Tests

April 2007: Shelter and TM equipment installation at Santa Maria

July 2007: Commissioning of Powerplant

October 2007: Start of antenna commissioning at Santa Maria

December 2007 / January 2008: Antenna fully validated for AR5

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Station system overview

Inmarsat

ISDN

Groundstation

Ariane-5 TM Kit

CSG/Kourou

Antenna

S-b

and

Program Track

VoiceInterface

TM ReceiverFrame sync,

Timestamping

AntennaControl Unit

Voice

Pointing(DO)

S-band

Decommutation,CVI Extraction

TM

CVI

Ground commsInterface

AntennaPointing

Telephone

Servo

LNA

Down-Converter

Tracking RX(Dual Frequency)

S-band S-band

Auto Track

Timing

Frequencyand

Time

Test signal

S-band

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

X-band option

To allow reception of Earth observation satellites in the 8025-8400 MHz band the antenna is equipped with a dual feed and dichroic sub-reflector.

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Major differences compared to satellite RF-links

Dual frequency transmission. One antenna on each side of the spinning launcher

Telemetry modulation: frequency shift (not CCSDS) , no remnant carrier. 1 Mbps

No Kepler orbit during launcher propulsion phase. Continuous position updates that may have large errors.

High angular velocity due to close distance ( 180 km , 7 km/s)

Communication using HDLC protocol

ISDN and Inmarsat satellite link to Kourou

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Existing concrete platform

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Equipment shelter and Telemetry kit

Reuse existing design of TM-kit developed for Ariane tracking network by Carlo Gavazzi Space

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Calibration tower

Guests on existing tower at Pico Alto

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Antenna supplied by Indra Espacio. Assembly at factory. Partly new design. 5.5 m dish, Carbon fibre

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Antenna installed at Santa Maria

X-Y mount (no singularity at zenith)

Inmarsat antenna

Radio link to calibration tower

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Murphy’s law

If anything can go wrong, it will.

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Filters required to reject UMTS ( mobile phone )

Filters supplied from US company.

Delayed delivery due to ITAR

Receive band

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Unexpected problems, wrong paint.

Glossy paint was used on the reflector. Feed cover burnt when pointing to the sun during G/T tests.

Repainting of reflector required

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Unexpected problems, autotrack patterns

Error in computer simulation of antenna pattern for the autotrack feed. Actual pattern gave larger angular offset than expected.

Original feed design

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Unexpected problems, autotrack patterns

Computer simulation

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Antenna tracking pattern measured

Error signal

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

New feed New feed design solved the issue.

4 lateral dipoles closer together. Sum signal generated by combining signals from the lateral dipoles.

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Antenna tracking pattern new feed

Error signal

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Unexpected problems, bad cables

RF cables after Low noise amplifier with 60 dB gain with damaged screen. ( Cut through at manufacturing and covered so not visible )

Caused the receive system to self oscillate at 2.2 GHz.

Leaking cable

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Unexpected problems. RFI from microwave link

Microwave links at Azores used the same frequencies as foreseen for Ariane 5.

Local coordination possible. Microwave links could move to other frequencies.

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Unexpected problems. Broken RF cables.

Cables from antenna are passing over a cable chain that is bent up to 180 degree each pass.

Selected coax cables had solid centre conductor not suitable for repeated bending.

Cables replaced , first temporary with RG223 available on site.

After AR5 support replaced to RG214 High Flex cables.

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Servo system not optimised

Large pointing errors when tracking moving targets.

Servo system software corrected

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Rough climate conditions.

Rust

Replace bolts with better quality, and repaint

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Boris Smeds OPS-GSY 2008-08-15 OPS-G Forum

Useful tool for maintenance