Multi Year SLR Solution - NASA · 2004. 8. 12. · Multi Year SLR Solution Horst Müller, Detlef...
Transcript of Multi Year SLR Solution - NASA · 2004. 8. 12. · Multi Year SLR Solution Horst Müller, Detlef...
Multi Year SLR Solution
Horst Müller, Detlef Angermann,Barbara Meisel
14th International Workshop on Laser Ranging, San Fernando, Spain, June 7 – 11, 2004
Deutsches Geodätisches Forschungsinstitut, MünchenE-Mail: [email protected]
Motivation
• SLR TRF realization• Contributions to various IERS
projects• Reference for station coordinates
(operational weekly computations)• J2 series• Geocenter and scale
Satellite Tracking Data Used
• All SLR tracking data• LAGEOS-1: Jan. 1981 – May 2004• LAGEOS-2: Oct. 1992 – May 2004• 2 min. normal points computed at DGFI
from FR-data, till 1988• 2 min. normal points from CDDIS• 2 min. onsite normal points, provided by
EDC, since Dec. 1993
Models used for Weekly Arcs
• Models: IERS 2000 Conventions
• Gravity Field: EGM96(to 20x20)
• Biases: significant biases adjusted
• Weighting: loose constraints (1m)
• EOP IERS C04
• Apriori station coord./vel.: DGFI-solution
• Datum: no net rotation on core stations
Solved Parameters
• 6 Orbital Elements• Once per rev. Along-track: 1/arc• Once per rev. Cross-track: 1/arc• Emp. Alongtrack-Paramter: 3/arc• Solar Radiation Correction: 3/arc
• Daily EOP‘s (X,Y,UT1)• Station Coordinates (epoch center of arc)
DOGS Processing Scheme
Weekly single satellite arcs
Conv.
Weekly single satellite arcs
Conv.
Solution Solution
LAGEOS-1 LAGEOS-2
Normals Normals
Biases,outliersBiases,outliers
NormalsNormals NormalsNormalsNormalsNormals
NormalsNormals
Weekly combination
Weeklycomb.sol.Normals combinationcombination
combinationLAGEOS-1/2
solutionLAGEOS-1
solutionLAGEOS-2
solution
NormalsNormals
Number of Normal Points
0
500
1000
1500
2000
2500
3000
3500
4000
4500
19811984
19871990
19931996
19992002
LAGEOS-2LAGEOS-1Edited Obs.
Weekly Orbital Fit [cm]
0
3
6
9
12
15
18
19821985
19881991
19941997
20002003
LAGEOS-1LAGEOS-2
Number of Biases per Week
0
5
10
15
20
25
30
35
19821985
19881991
19941997
20002003
LAGEOS-1LAGEOS-2
Weekly J2 Values(Relative to 1.0826e-3)
-40
-35
-30
-25
-20
-15
-10
1981
1984
1987
1990
1993
1996
1999
2002
LAGEOS-1
LAGEOS-2
[1e-9]
Recent Solution
• Time span Jan. 1999 – May 2004
• LAGEOS-1 and 2 combined
• Datum: no net rotation conditions
• Comparison with ITRF2000
• Comparison with GPS and DORIS onweekly basis
Comparison DGFI - ITRF2000 (Europe)
Comp. DGFI – ITRF2000 (East Asia)
Time Series of Weekly TranslationParameters
Position Time Series (Yarragadee)
-6-3036
nort
h [cm
]
-6-3036
ea
st
[cm
]
-6-3036
1999 2000 2001 2002 2003 2004
up [cm
]
Station Height Variations
Annual signals in station heights
Future Plans
• 12-Years comb. solution (10/92-06/04)• Combined solution 1981-2004• Seasonal signals in positions, low
degree harmonics• Continuous update of solutions• Provide results at
http://ilrsac.dgfi.badw.de/
Position Time Series (Herstmonceux)
-3
0
3
nort
h [cm
]
-6-3036
ea
st
[cm
]
-3
0
3
1999 2000 2001 2002 2003 2004
up [cm
]
Number of Station per Week
0
5
10
15
20
25
30
35
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
LAGEOS-1LAGEOS-2
Number of Passes
0
50
100
150
200
250
300
350
400
1981198219831981
19821983
19841985
19861987
19881989
19901991
19921993
19941995
19961997
19981999
20002001
20022003
2004
LAGEOS-2LAGEOS-1
Comparison DGFI – ITRF2000(South Africa)