March 1 & 2, 2005 NC&I WG GGOS Meeting/GFZ 1

International Laser Ranging Service

GGOS Meeting

GFZ

Potsdam Germany

March 1 and 2, 2005

March 1 & 2, 2005 NC&I WG GGOS Meeting/GFZ 2

ILRS Organization

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Data Applications

• Earth orientation parameters (polar motion and LOD)

• 3-D coordinates and velocities of the ILRS tracking stations

• Time-varying geocenter coordinates

• Static and time-varying coefficients of the Earth's gravity field

• Precision Orbit Determination

• Fundamental physical constants

• Lunar ephemerides and librations

• Lunar orientation parameters

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ILRS Analysis and Associate Analysis Centers

• ILRS SLR Official Combination Centers

– Prime: ASI/CGS, Italian Space Agency/Space Geodesy Center, Italy

– Alternate: DGFI, Deutsches Geodaetisches ForschungsInstitut, Germany

• Active Contributors to the SLR Combination Products

– ASI/CGS, Italian Space Agency/Space Geodesy Center "G. Colombo", Italy

– DGFI, Deutsches Geodaetisches ForschungsInstitut, Germany

– BKG, Bundesamt fuer Kartographi und Geodaesie, Germany

– GFZ, GeoForschungsZentrum, Germany

– JCET, Joint Center for Earth Systems Technology, USA

– NSGF, NERC Space Geodesy Facility, UK

• Lunar Analysis Centers

– FFI, Forsvarets ForskningsInstitut, Norway

– JPL, Jet Propulsion Laboratory, USA (SLR and Lunar)

– OCA, Observatoire de la Cote d'Azure, France (Lunar)

– POLAC, Paris Observatory Lunar Analysis Center, France (Lunar)

– University of Texas, Lunar Analysis Center (Lunar)

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Other SLR Analysis and Associate Analysis Centers

– AIUB, Astronomical Institute of Berne, Switzerland

– CSR, Center for Space Research, U. of Texas

– DUT, Delft University of Technology, The Netherlands

– ESA/ESOC, European Space Agency/ESA Space Operations Center, Germany

– GAOUA, Main Astronomical Obser., National Academy of Sciences, Ukraine

– Geoscience Australia

– IAA, Institute of Applied Astronomy, Russia

– JAXA, Japan Aerospace Exploration Agency

– JPL, Jet Propulsion Laboratory, USA

– MCC, Mission Control Center, Russia

– Newcastle University, UK

– NICT, National Institute of Information and Communications Technology, Japan

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ILRS Customers

• IERS

• Supported Missions (POD)

• ILRS Analysis Centers

• Academic Research Centers

• National Agencies and Laboratories

• Commercial Organizations

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Current ILRS Missions SupportGravity Probe-B Relativity

ICESat Global Topography (Ice, Oceans, and Land)

GRACE-A/B Static and Time Varying Gravity Field

CHAMP Gravity and Magnetic Field

GFO-1 ** Ocean Topography

Envisat Ocean Topography, Atmosphere

ERS-2 ** Ocean Topography, Atmosphere

Jason Ocean Topography

TOPEX/Poseidon ** Ocean Topography

Larets * Technology, Gravity Field

Starlette, Stella * Static and Time Varying Gravity Field, Tides

Meteor-3M ** Technology, SAGE

Ajisai * Gravity Field

LAGEOS- 1, 2 * Ref. Frame, Positioning, Static and T/V Gravity

Beacon-C * Static and Time Varying Gravity Field

Etalon-1, 2 * Positioning, EOP

GLONASS-84, 87, 89 Orbit calibration and validation

GPS-35, 36 Orbit calibration and validation

Lunar Reflectors: Apollo15, Apollo 11, Apollo 14, Luna 21, Luna 17

Key: * Passive Satellites ** Active satellites with SLR tracking only

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Upcoming Missions

Mission Application Launch

CRYOSat Ice budget July 2005

Galileo (2) Orbit calibration and validation October

2005

ALOS Environmental remote sensing Late 2005

GOCE Gravity Field, Geoid, Ocean Surface 2006

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ILRS Station Operations

• Location of Stations • Most stations are located close to participating agencies• Some are located to enhance global distribution (South Africa, Tahiti,

Arequipa)• Voids in global distribution

• Satellite Priorities• Priorities decrease with increasing orbital altitude and then increasing

orbital inclination• Priorities may be increased to intensify support for active missions (such as

altimetry), special campaigns, and post-launch intensive tracking• Priorities are reviewed and approved by the Governing Board• See http://ilrs.gsfc.nasa.gov/satellite_missions/priorities/index.html

• Scheduling, Coordination and Delivery of Observations • Stations tracking schedules range from 1 to 4 shifts per week• Stations track according to priorities, predictions and their local capabilities• The Governing Board approves special campaigns• Special procedures (e.g. for vulnerable satellites) are approved by the

Governing Board and managed by the Central Bureau• Data is delivered in 1 -2 hours from acquisition

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Laser Ranging Data and Data Products• Satellite Laser Ranging

• Data series spanning 3 decades at ftp://cddis.gsfc.nasa.gov/pub/slr/data)

• Operational Satellite Ephemerides/predictions at ftp://cddis.gsfc.nasa.gov/pub/slr/predicts)

• ILRS Station and EOP Combination Product (SINEX format)

– Station Coordinates: 3 mm; 2 mm/year

– EOP: 0.2 milliarcsec: LOD 60 microsec.

• Analysis Center contributions

– Station Coordinates

– Earth Origin

– Temporal and static gravity field (long wavelength)

– LAGEOS Orbits (10 mm/weekly)

• Position and EOP contributions available at ftp://cddis.gsfc.nasa.gov/pub/slr/products

• Lunar Laser Ranging

• Lunar Ephemerides: 5 - 10 cm

• Lunar Libration: .01 arcsec.

• Products available at http://ssd.jpl.nasa.gov/horizons.html

• Measurement and product standards?

• Station Qualification Criteria ( data quantity, data quality, operational compliance)

• See http://ilrs.gsfc.nasa.gov/stations/site_info/global_report_cards/

• Analyses follows IERS conventions

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ILRS Future Activities

• Upgrades for improved performance (short term, long term)

• kilohertz ranging

• autonomous operation (24/7)

• improved event timers

• two-color ranging (refraction)

• better control systems for more efficient satellite pass interleaving

• more compact retroreflector arrays

• continuous data flow

• transponder operations (LLR and planetary ranging)

• broader applications (communications)

• Improved modeling (S/C center of mass, propagation, etc.)

• New Missions that will improve measurement quality

• Additional passive, high mass density satellites in new orbits

• Key Issues

• Deterioration of the network

• Non-performing stations

• Global distribution