GOES-R Program Calibration and ValidationRobert A. Iacovazzi, Jr.* (1), Edward C. Grigsby (1), Steve Goodman (2), Changyong Cao (3),
Jaime Daniels (3), and Kathleen McIntyre (1)NASA (1), NOAA/NESDIS/GOES-R (2), and NOAA/NESDIS/STAR (3)
[email protected] Physical Address - NASA GSFC, Code 410.0, 8800 Greenbelt Rd, Greenbelt, MD 20771
PRE-LAUNCH INSTRUMENT CALIBRATION and L1B ALGORITHM DEVELOPMENT
Government Validation of Vendor Cal TestingGOES-R Flight Project and Calibration Working Group (CWG)• Give feedback regarding vendor cal test plans and readiness• Analyze vendor cal test reports for fidelityUS National Institute of Standards and Technology (NIST)• Support design of Système international d'unités (SI) traceable calibrations of ABI and EXIS• Establish SI-traceability to primary standards through NIST supported testing• Independently validate mission-critical component performance, e.g., SRF• Review vendor cal plans and test setups to ensure they meet NIST best practices
Laboratory Instrument Calibration (Cal)• Verify instrument cal and product requirements are satisfied• Determine values of semi-static L1b algorithm input parameters• Ensure instrument performance is well understood and documented
Radiometric Characterization & Calibration
Spectral Response
Function (SRF)
Image Navigation & Registration
Spatial Resolution &
Response• Response linearity and dynamic
range• Signal-to-Noise, NEDN, and
Coherent Noise• Radiometric repeatability to a stable
and uniform scene• Irradiance to radiance transfer
(VNIR)• External/Internal calibration target
comparison (TIR)• Polarization (VNIR)• Optical and electronic cross talk• In-flight electronic calibration• Blooming• Quantization step size• Hot, marginal and dead pixels
• Envelope• Uniformity over
the focal plane detector array
• Out-of-band response
• Uncertainty• Inference of
possible SRF shifts
• System-level and integrated component-level consistency
• Navigation (including star sensing)
• Frame-to-frame, within frame, swath-to-swath, and channel-to-channel registration
• System modulation transfer function
• Spatial response uniformity (e.g., response vs. scan angle)
• Ringing from a sharp edge
• Near and far field scatter
• Ghosting• Pointing
knowledgeInstrument manufacturers design and perform cal tests, and this
table lists cal-related ABI testing carried out by Exelis.
L1b Tiger Team Mandate Proactively identify and mitigate risks
associated with implementing L1b algorithms
L1b Tiger Team Meetings
Instr. Vendor
L1b Dev
Gov’t Instr
Manager
Gov’t CWG/Flight
L1b Validaton
L1b Alg and Test Data and
RFA Responses
Portal
RFA & RFA Responses
L1b Alg Reviews and RFA
Gov’t GS ManagerL1b Alg and
Test Data and RFA
Responses
RFA & RFA Responses
L1b Alg and Test
Data and RFA
Responses
L1b Alg and Test Data and RFA Responses
L1b algorithm implementation process (RFA – Request for
Action)
Key L1b Algorithm Quality Assurance
• Evaluate L1b algorithm completeness
• Identify, track, and resolve L1b algorithm issues
• Assess Ground Segment vendor L1b algorithm implementation
• Develop instrument calibration data and product metadata definitions
GS Vendor
L1b Implem
On-Board Cal Devices Vicarious Targets Space-based Inter-Calibration
ABI
• IR Cal (NEDT[@300K]: 0.1K all but 13.3 mm, 0.3K for 13.3 mm) – Blackbody
• VNIR Cal (SNR 300:1 @ 100% Albedo) - Solar Diffuser
• Self-Emission - Space View• Electronics Linearity - Electronic Stimulus
• VNIR Cal - Moon, Stars, Deserts, Test Sites, Deep Convective Clouds (DCCs), Rayliegh Scattering, etc.
• MTF, B2B Reg - Moon
• VNIR/IR Cal - GEO and LEO Imagers
• Spectral Cal – Hyperspectral Sounders
GLM None Response Cal - DCCs, Deserts, Sun-glint
Response Cal - GEO and LEO Imagers
EXIS• Response Linearity - Light Sources• Dark Measurements and Flatfields - Off-point Mechanism
• Electronics Linearity - Electronic Stimulus
Response Flatfield - Sun Response Cal – GEO Solar Sensors
SUVI
• Aliveness - Light Source• Dark Measurements and Flatfields - Off-point Mechanism
• Out-of-band Rejection - Glass/Analysis Filters • Electronics Linearity - Electronic Stimulus
Response Flatfield - Sun Response Cal - EXIS and other GEO Solar Sensors (e.g., SDO/EVE)
SEISS Electronics Linearity - Electronic Stimulus None Response Cal – GEO Particle Sensors
MAG Electronics Linearity - Electronic Stimulus None Response Cal - GEO Mag Sensors
POST-LAUNCH CALIBRATION/VALIDATION (CAL/VAL)
GOES-R observatory on-orbit cal/val assets
Calibration – Processes to transform raw GOES-R instrument data into L1b measurements … the fundamental building blocks for all L2+ products.
Validation - Provides user confidence that GOES-R data can be used for their intended purpose, e.g., weather forecasting or numerical weather prediction.
Example comparison between GOES-R CWG and Vendor cal test analyses: Ratio of CWG to Exelis cal
coefficients for ABI reflective channels.
Before (left) and after (right) Government-Vendor reconciliation of scan mirror reflectance value used in ABI test data analysis.
Post-Launch Testing (PLT) Cal/Val• Validate that instrument cal and product performance supports a system that meets its intended
purpose in its intended environment as outline in the GOES-R Concept of Operations• Resolve instrument cal and product performance anomalies to the degree possible as they arise• Create a “state-of-the-cal” snapshot for long-term instrument/product performance trending
GOES-13 Hemispheric Image Tiles
Product quality evaluation
Ch. 2 Ch. 3 Ch. 5Ch. 4
Ch Det Average GOES-10 Prelaunch (K)
GOES-10 On-Orbit (K)
GOES-9 On-Orbit (K)
2 A 0.1163 0.0933 0.1065 B 0.1259 0.1007 0.1090
3 --- 0.1480 0.1324 0.1231 4 A 0.0725 0.0703 0.0710
B 0.0771 0.0757 0.0705 5 A 0.1573 0.1516 0.1725
B 0.1568 0.1506 0.1825 On-board calibration system evaluation
Determine and Correct Scan-Angle Dependent Radiance (e.g., Beaucom et al., Proceedings
of SPIE, 1999)
Instrument Noise, Blackbody Temp and Cal Slope Monitoring
GOES-13 eclipse season stray light before fix (left) and after fix (right) (Courtesy of J. Paul Douglas, OSPO)
On-orbit calibration and L1b anomaly resolution
GOES-10 Ch. 4A
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