Download Performance Solid Earth Physics

Performance
Processing Scheme from Level 0 to Level 3
GOCE
Mature Processing Methods and Algorithms
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 59
Performance
Simulation Input
GOCE
mission characteristics
measurement duration
orbit
12 months
almost circular
altitude 250 km
96.5
un-synchroneous)
position errors in monitoring
the SST high-low (GPS/GLONASS)
x (along track)
y (cross-track)
z (radial)
2 cm / Hz
1 cm / Hz
3 cm / Hz
gravity gradiometer error spectrum
frequency
f < 10-3 Hz
frequency
510-3 < f < 10-1 Hz
full diagonal instrument (Vxx,Vyy,Vzz) and Vxz
1/f coloured noise
white noise < 510-3 E / Hz
measurement sampling time
1 second
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 60
Performance
End-to-End Simulation Scheme
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
GOCE
S 61
Performance
Four Error Classes
GOCE
instrument errors
satellite errors
instrument/satellite coupling errors
post processing errors
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 62
Performance
The 4 Error Classes: Simulated Results
Instrument Error
Coupling Error
Satellite Error
Post-Flight Error
GOCE
this total error is
used in the geoid
and gravity field
retrievals
Total Error
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 63
Performance
Spherical Harmonic Error Spectrum
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
GOCE
S 64
Performance
Spectral Error Results
GOCE
1 cm geoid and 1 mgal gravity field accuracies are well recovered at
wavelength of 100 km (degree and order 200)
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 65
Performance
Spatial Error Results
GOCE
1 cm geoid and 1 mgal gravity field accuracies are well recovered at
wavelength of 100 km (degree and order 200) for all latitudes except
near the poles.
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 66
Performance
Science Requirements: Summary
GOCE
science requirements
AP PLICATION
ACCURACY
Gravity
(mGal)
1-2
SP AT IAL
RESOL UT ION
half wavelength - D
(km)
100
sedimentary basins
rifts
tectonic motions
seismic hazards
1-2
1-2
1-2
1
50-100
20-100
100-500
100
ocean lithosphere / asthenosphere
0.5
100-200
G eoid
(cm)
lithosphere / upper mantle density
continental
lithosphere
SO LID EARTH
short scale
OCEANOG RAP HY
ICE SHEETS
GE ODESY
basin s cale
rock basement
ice vertical movements
lev elling by GPS
unified height systems
INS
orbits
1-2
0.2
~ 0.1
2
1
1
SEA LEVE L CHANG E
are
100
200
1000
1-5
50-100
100-1000
100-1000
100-20000
~ 1-5
100-1000
~ 1-3
100-1000
Many of the above applications,
with their specific requirements,
relevant to studies of sea level change
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 67
Performance
Simulation Results
GOCE
simulated GOC E perform ance
spatia l resolution D
(half wavelength )
m aximum deg ree L
(corresponds to D )
ge oid heig ht
[mm ]
gravity anoma ly
[m Gal]
1000 km
20
0.4
0.0006
400 km
50
0.5
0.001
200 km
100
0.6
0.03
100 km
200
2.5
65 km
300
~ 45
10
0.08
1
~2
the simulated results suggest excellent performance versus scientific
requirements
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 68
Performance
Solid Earth Physics
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
GOCE
S 69
Performance
Oceanography
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
GOCE
S 70
Performance
Geodesy
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
GOCE
S 71
Conclusions
Uniqueness and Complementarity
GOCE
• GOCE will be the first gravity gradiometer in space
• an ambient temperature, capacitive gradiometer instrument is
selected in combination with GPS high-low tracking
• GOCE will map the Earth’s gravity field in three dimensions
providing a:
- geoid error < 1 cm at 100 km spatial resolution
- gravity field error << 1 mgal at 100 km spatial
resolution
• The GOCE data will complement data from altimetric missions,
Oersted, CHAMP, GRACE, ICESAT and Cryosat
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
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Conclusions
Advancement of European E.O. capabilities
GOCE
• the gradiometer accelerometers and GPS receiver are based on
European technology
• the drag free system technology offers new opportunities in a
wide range of applications including E.O. from low orbit
altitude
• a multi-disciplinary user community within fields of Solid
Earth Physics, Geodesy and Oceanography is well prepared to
utilize the new and accurate gravity field and geoid data at
high spatial resolution
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 73
Conclusions
Feasibility and Level of Maturity
GOCE
•
all technologies have been demonstrated (except micro-thrusters)
and the development schedule is acceptable
•
an end-to-end and closed loop simulator provides realistic
and comprehensive insight into system performance from
the sensor level to the retrievals of the gravity field and
geoid signals
•
the processing schemes (from Level 0 to Level 3) and
algorithm maturity are meeting the requirements
•
impact studies show very promising results for applications
in the disciplines of solid Earth physics, absolute ocean
circulation and geodesy
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 74
Conclusions
Timeliness and Programmatics
GOCE
•
the GOCE Mission is very timely in the context of the user
needs and their associated readiness
•
no implementation constraints exist
•
the proposed launch in 2004 is in the low activity region of
the solar cycle)
•
the expected launch in late 2006 still OK.
The Four Candidate Earth Explorer Core Missions Consultative Workshop
12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT
S 75