IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 20031 H. Fagard (IGN)
THE DORIS NETWORK: STATUS REPORT ON RENOVATION AND COLLOCATIONS
Hervé FAGARD (Institut Géographique National)
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 20032 H. Fagard (IGN)
The network on 2003/01/01
• 56 stations, 33 countries • Circles: SPOT-n & Envisat, 12°
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 20033 H. Fagard (IGN)
Distribution of the DORIS equipment
Version 1.0 or 1.1 beacon
Alcatel antennaStarec
antenna
Version 2 beacon
+
+
9 stations
Version 3 beacon
24 stations
Alcatel antennaStarec
antenna
+
+
1 station 9 stations
Alcatel antennaStarec
antenna
+
+
1 station 12 stations
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 20034 H. Fagard (IGN)
0
10
20
30
40
50
1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Number of stations (end of the year) Renovations
SPOT-2TOPEX
SPOT-3
Evolution of the network
SPOT-4JASON
ENVISATSPOT-5
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 20035 H. Fagard (IGN)
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
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 20036 H. Fagard (IGN)
Network renovation progress
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 20037 H. Fagard (IGN)
Antennas estimated stability (2002/01/01)
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 20038 H. Fagard (IGN)
Collocations with other IERS techniques:theoretical 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
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 20039 H. Fagard (IGN)
Theoretical/actual number of collocations
DORIS collocation with: theoretical actual
SLR only 1 0
GPS only 17 21
VLBI+GPS (no SLR) 7 5
SLR+GPS (no VLBI) 5 6
VLBI+SLR+GPS 6 1
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 200310 H. Fagard (IGN)
Theoretical collocations with other IERS techniques
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 200311 H. Fagard (IGN)
Actual collocations with other IERS techniques
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 200312 H. Fagard (IGN)
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)
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 200313 H. Fagard (IGN)
DORIS-DORIS collocations (2)
IDS Workshop - ENSG Marne-la-Vallée - February 20-21, 200314 H. Fagard (IGN)
Tide gauges collocations (<10 km)
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