eum/ops/vwg/11 issue 1.0 22/06/2011 yoke yoon yago andres christian marquardt cosmic gps data...
TRANSCRIPT
EUM/OPS/VWG/11Issue 1.022/06/2011
Yoke YoonYago AndresChristian Marquardt
COSMIC GPS Data Processing
Slide: 1
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Introduction
• Overview of Precise Orbit Determination (POD) activities• COSMIC GPS data processing
• Status of GPS-based POD for COSMIC• Preliminary results
• Future activities/goals• Reprocessing of COSMIC data (2006-current) for whole
constellation (POD and RO)• Data reprocessing of other RO missions (CHAMP, GRACE,
OceanSat-2)• NRT operational POD for future Metop-B (2012), Metop-C
(2016/2017)• NRT offline POD for Jason-3
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Overview of GPS data processing activities (1/2)
• MetOp-A operational NRT • Utilize NRT GPS orbit & clock products from GRAS Ground
Support Network (operated by ESOC/ESA)• Based on (batch) sequential estimation• RO data processing
• MetOp-A offline POD• Utilize Rapid GPS orbit & clock products from CODE• Based on batch estimation
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Overview of GPS data processing activities (2/2)
• Jason-2 offline NRT POD• Utilize NRT GRAS GSN products• Batch estimation
• COSMIC GPS data processing• Final (Precise) GPS products from CODE/AIUB• (POD) Batch estimation• RO data processing
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COSMIC GPS Data Processing
• GPS-based POD status• Raw data assessment• Investigate various processing options• Orbit (internal & external) assessment• Planned POD-related activities/analysis
• GPS RO (not yet started)
• Processing of GPS data from the ROantennas
• Derive bending angles and refractivity profiles
• Timeline of reprocessing activities• COSMIC POD (from Level-0) commences after summer 2011• POD and RO product delivery to ECMWF by end of 2012 (GRAS,
COSMIC, CHAMP, GRACE)
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COSMIC GPS Data Processing
Nominal flightdirection
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COSMIC GPS Data Processing
• Assessment of raw data• GPS receiver tracking
performance over time• Easy identification of POD
problems that arise from s/c tracking or data outages
• Planned to be included in theoperational processing facility as part of the monitoring system for future missions
COSMIC FM 6
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COSMIC GPS Data Processing
• Assessment of raw data
COSMIC FM 6 (IGOR)MetOp-A (GRAS)
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COSMIC GPS Data Processing
• POD processing strategy• Use of quaternion for s/c orientation knowledge • GPS phase and pseudorange observations sampled at 1 min (no
smoothing)• Precise GPS orbit and (30s) clock product from CODE/AUIB • Parameter settings in NAPEOS gear more toward s/c modelled
dynamics weight on phase data, = 3 cm weight on pseudorange, = 6 m
• 30-hr arc (6-hr overlap between consecutive arcs)• 7 consecutive days of COSMIC FM#6 GPS observation data
( 26 Nov – 2 Dec 2008 )
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COSMIC GPS Data Processing
• Parameter estimates• COSMIC state vector (position & velocity) and clock offset• Step-wise constant drag coefficient (12/arc)• SRP coefficient (1/arc)• 1/rev sine and cosine along- and cross-track empirical
accelerations (1/arc)• Carrier phase bias (per pass)
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COSMIC GPS Data Processing
Dynamic Models
Gravity field model EIGEN-GL04C (100 x 100)
3rd body perturbation JPL DE405 ephemerides
Solid Earth, Pole & Ocean tides Applied
Relativistic correction & drift Applied
IR & Albedo radiation Applied
Atmospheric density & SRP Constant area
Measurement models
Ionosphere Linear combination
Phase wind-up Applied
Antenna phase center corrections (offset & variation)
Nominal values appliedCorrections applied
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COSMIC GPS Data Processing
• External orbit product for comparison• UCAR (website)
• 27-hr arc (Day 1 00:00:00 – Day 2 03:00:00)• JPL (special request)
• 30-hr arc (Day 0 21:00:00 – Day 2 03:00:00)
• Orbit overlap assessment• Shows the median of 6 sets of overlap (RMS) statistics
Position (cm) Velocity (mm/s)# pts (per set)
R T N 3D R T N 3D
EUMETSAT
1.6 4.0 2.5 5.2 0.03 0.02 0.03 0.04 241
JPL 1.6 2.8 0.7 3.4 0.02 0.02 0.01 0.03 241
UCAR 1.9 2.2 2.2 3.8 0.02 0.02 0.01 0.03 121
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COSMIC GPS Data Processing
• External orbit product for comparison• UCAR (website)
• 27-hr arc (Day 1 00:00:00 – Day 2 03:00:00)• JPL (special request)
• 30-hr arc (Day 0 21:00:00 – Day 2 03:00:00)
• Orbit overlap assessment• Shows the median of 6 sets of overlap (RMS) statistics
Position (cm) Velocity (mm/s)# pts (per set)
R T N 3D R T N 3D
EUMETSAT
1.6 4.0 2.5 5.2 0.03 0.02 0.03 0.04 241
JPL 1.6 2.8 0.7 3.4 0.02 0.02 0.01 0.03 241
UCAR 1.9 2.2 2.2 3.8 0.02 0.02 0.01 0.03 121
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COSMIC GPS Data Processing
• Inter-comparison time period• EUM vs JPL (24-hrs) 00:00:00 - 24:00:00• EUM vs UCAR (23-hrs) 01:00:00 – 24:00:00• UCAR vs JPL (23-hrs)
• Shows the median of 7 sets of daily RMS statistics
Position (cm) Velocity (mm/s)# pts (per set)
R T N 3D R T N 3D
EUM-JPL 5.4 16.7 3.9 18.2 0.14 0.06 0.05 0.17 1441
EUM-UCAR
5.8 10.6 4.9 13.1 0.11 0.06 0.07 0.14 1381
UCAR-JPL 5.9 11.8 5 13.9 0.11 0.08 0.08 0.15 1381
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COSMIC GPS Data Processing
• Planned activities• Smoothing of the quaternion
Quaternion derived frommagnetometer, Earth (highest weight) & Sun sensors
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COSMIC GPS Data Processing
• s/c orientation (Euler angles)
COSMIC s/c tumbles constantlyas it does not maintain a 3-axis stable attitude
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COSMIC GPS Data Processing
• Planned activities• Smoothing of the quaternion• Simultaneous processing of GPS data from two antennas (same
s/c)(JPL COSMIC POD is based on this)
POD antenna #1 from COSMIC FM 6
POD antenna #2 from COSMIC FM 6
flightdirection
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COSMIC GPS Data Processing
• Preliminary assessment (overlap of DOY 332-333 of 2008) of FM2
Position (cm) RMS Velocity (mm/s) RMS# pts
R T N 3D R T N 3D
EUM (1 Ant)
2.3 5.2 2.1 6.0 0.03 0.02 0.02 0.05241
EUM(2 Ant)
1.3 2.8 1.1 3.3 0.02 0.01 0.01 0.02241
JPL 0.5 1.3 0.5 1.5 0.01 0.004 0.005 0.01 241
UCAR 3.2 3.2 6.3 7.8 0.03 0.04 0.04 0.06 121
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COSMIC GPS Data Processing
• External assessment (average of DOY 332 & 333 of 2008) of FM2Position (cm) RMS Velocity (mm/s) RMS
R T N 3D R T N 3D
EUM-JPL(1 Ant)
2.8 8.5 5.9 10.8 0.07 0.03 0.04 0.09
EUM-JPL(2 Ant)
2.3 11.5 4.5 12.6 0.11 0.03 0.04 0.12
EUM-UCAR
(1 Ant)6.9 12.5 7.4 16.2 0.12 0.07 0.10 0.18
UCAR-JPL 6.8 8.5 6.8 12.9 0.08 0.07 0.10 0.15
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COSMIC GPS Data Processing
• External assessment (average of DOY 332 & 333 of 2008) of FM2Position (cm) RMS Velocity (mm/s) RMS
R T N 3D R T N 3D
EUM-JPL(1 Ant)
2.8 8.5 5.9 10.8 0.07 0.03 0.04 0.09
EUM-JPL(2 Ant)
2.3 11.5 4.5 12.6 0.11 0.03 0.04 0.12
EUM-UCAR
(1 Ant)6.9 12.5 7.4 16.2 0.12 0.07 0.10 0.18
UCAR-JPL 6.8 8.5 6.8 12.9 0.08 0.07 0.10 0.15
Position along-track bias (cm)
EUM (1 Ant) vs JPL
EUM (1 Ant) vs UCAR
UCAR vs JPL
DOY 332 -6.0 -10.5 4.2
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COSMIC GPS Data Processing
• External assessment (average of DOY 332 & 333 of 2008) of FM2Position (cm) RMS Velocity (mm/s) RMS
R T N 3D R T N 3D
EUM-JPL(1 Ant)
2.8 8.5 5.9 10.8 0.07 0.03 0.04 0.09
EUM-JPL(2 Ant)
2.3 11.5 4.5 12.6 0.11 0.03 0.04 0.12
EUM-UCAR
(1 Ant)6.9 12.5 7.4 16.2 0.12 0.07 0.10 0.18
UCAR-JPL 6.8 8.5 6.8 12.9 0.08 0.07 0.10 0.15
Position along-track bias (cm)
EUM (1 Ant) vs JPL
EUM (2 Ant) vs JPL
EUM (1 Ant) vs UCAR
EUM (2 Ant) vs UCAR
UCAR vs JPL
DOY 332 -6.0 10.6 -10.5 6.1 4.2
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COSMIC GPS Data Processing
• Planned activities• Smoothing of the quaternion• Simultaneous processing of GPS data from two antennas • Analyze the existence of an along-track bias in inter-agency orbit
comparison• POD parameter tuning (i.e. drag coefficient)
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COSMIC GPS Data Processing
• Planned activities• Smoothing of the quaternion• Simultaneous processing of GPS data from two antennas (from same
s/c) • Analyze the existence of an along-track bias in inter-agency orbit
comparison• Automate reprocessing of 5-6 years of data for 6 s/c
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COSMIC GPS Data Processing
• Planned activities• Smoothing of the quaternion• Simultaneous processing of GPS data from two antennas (from same
s/c) • Analyze the existence of an along-track bias in inter-agency orbit
comparison• Automate reprocessing of 5-6 years of data for 6 s/c• Processing of COSMIC RO data to derive bending angle & refractivity
profiles
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COSMIC GPS Data Processing
• Planned activities• Smoothing of the quaternion• Simultaneous processing of GPS data from two antennas (from same
s/c) • Analyze the existence of an along-track bias in inter-agency orbit
comparison• Automate reprocessing of 5-6 years of data for 6 s/c• Processing of COSMIC RO data to derive bending angle & refractivity
profiles
• Challenges in automating COSMIC POD• Handling of large data gaps
(especially at the beginning of the mission)• Handling of maneuvers• FM2 and FM5 had attitude control &
receiver anomalies in 2007
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End of Presentation
Questions?