THE DORIS NETWORK: STATUS REPORT ON RENOVATION AND COLLOCATIONS

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THE DORIS NETWORK STATUS REPORT ON RENOVATION
AND COLLOCATIONS
Hervé FAGARD (Institut Géographique National)
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The network on 2003/01/01

• 56 stations, 33 countries

• Circles SPOT-n Envisat, 12

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Distribution of the DORIS equipment
Version 1.0 or 1.1 beacon
Version 2 beacon
Version 3 beacon






Alcatel antenna
Alcatel antenna
Alcatel antenna
Starec antenna
Starec antenna
Starec antenna
9 stations
24 stations
1 station
9 stations
1 station
12 stations
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Evolution of the network
SPOT-5
ENVISAT
JASON
SPOT-3
SPOT-4
TOPEX
SPOT-2
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Network latest news

• Two new stations installed at the end of 2002
• Thule (Greenland)
• Sal (Cape Verde), replacing Dakar
• Theoretical orbit coverage (when all stations are
  operating)
• Low satellites (SPOT-2 , 4, 5 Envisat) 88
• High satellites (Topex Jason) 98
• Stations renovated in 2002
• Tristan da Cunha, Terre Adélie, Port Moresby,
  Kauai
• Next planned renovations
• Manila (next week)
• St Helena, Ascension (March)
• Mount Stromlo destroyed by fire in January
  should be rebuilt by mid-2003

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Network renovation progress
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Antennas estimated stability (2002/01/01)
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Collocations with other IERS techniquestheoretic
al vs. actual

• Many collocated instruments are not currently
  operating
• Discontinued long-term occupation by
• VLBI (Richmond, Santiago)
• SLR (e.g. Dionysos, Easter Island, Goldstone,
  etc.)
• Short duration (2 days only once, to a few days
  per year) mobile VLBI occupation (Toulouse, Ponta
  Delgada, Metsähovi, Greenbelt)
• Unreliable tie
• Insufficient accuracy, measured only once,
  sometimes many years ago
• Very long baseline, different geological
  movements (e.g. Kourou)
• Network future evolutions should aim at adding a
  few VLBI and SLR collocations

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Theoretical/actual number of collocations
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Theoretical collocations with other IERS
techniques
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Actual collocations with other IERS techniques
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DORIS-DORIS collocations (1)

• 29 DORIS stations have multiple antenna
  positions
• Two different antenna positions at 21 sites
• Three different antenna positions at 8 sites
• All ties between different antenna positions on
  the same site have been measured accurately,
  except
• AMSA-AMSB (approximate connection planned, AMSA
  no longer exists)
• HBKA-HBLA (antenna moved by host agency, no
  direct survey)
• HELA-HELB (antenna change by host agency, no
  survey)
• KERA-KERB (dubious KERA antenna height)
• GOLA-GOMA (no direct connection)

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DORIS-DORIS collocations (2)
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Tide gauges collocations (lt10 km)