MISR: In-Flight Radiometric Calibration and Characterization Plan

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these is on the order of 0.5 nm. The radiometric error for this slight a shift is quite small, but willbe included in any spectral error report.The more significant analysis to be done is that associated with the development of the inandout-of-band spectral scaling algorithms. These processing steps do not actually correct for aradiance error, but rather adjust the retrieved radiances to predict what would have been measuredwith a more ideal spectral response profile. The in-band spectral scaling algorithm corrects fordifferences in centroid center wavelength and in-band passband shape across the array and fromone camera to the next. The out-of-band adjustment subtracts that fraction of the output due toout-of-band response. In the current MISR product generation scheme, the in-band scaling isperformed at Level 1B1; out-of-band subtraction is performed upon generation of specific Level 2products. The out-of-band response correction is postponed until later in the product generationstream so as to allow registration of the four channels in each camera. This permits a crudemeasure of the scene spectral profile to be estimated and utilized within the retrieval algorithm.The development and validation of both spectral algorithms are the responsibility of the IFRCCteam.This task will evaluate the current correction sequence, as compared to an ideal approachof having band registration (or an AVIRIS-like scene spectral retrieval) available at the time ofLevel 1B1 processing. Also, the utilization of a representative line profile, rather than a moregeneral data set which characterizes the field angle differences, will need to be evaluated.Three data sets are identified for this work. First, a set of registered Level 1A data areneeded. This product is not available as a DAAC product, and will need to be generated at theSCF using code developed for us by the Science Data System Team. Second, AVIRIS data are tobe used in this study, as they provide samples of complete scene spectral distributions. MISR willwork with the JPL AVIRIS team for a data exchange which will provide these data sets. Finally, atypical MISR global data set will useful in evaluating the fraction of global data subject to thesereported worst-case spectral errors.7.1.3 Pixel non-uniformityOn-board averaging results in a radiometric error for scenes of high spatial contrast acrossthe pixels being averaged. Preflight testing has determined that the mean pixel responsedifference, piecewise across four-pixel blocks, is less than 1%. With this uniformity, it is rare thatsignificant errors will be incurred due to on-board averaging. There are, however, a half-dozen orso pixels per line which have response variations exceeding the 3% specification. Corrections forthese non-uniformities could be made, by using the high-resolution An (nadir) camera to measurethe relative surface inhomogeneity. This scene information could be used to correct errorsintroduced during data averaging. Although it is not possible to implement this approach in Level1B1 processing, a registered data set can be provided as a special request to the SCF. Thus, acomparison of the actual versus desired approach can be evaluated. The evaluation of a secondapproach, where the high-resolution red band data are used to infer scene inhomogeneity at otherwavelengths, has also been proposed. Unless there is a need to incorporate pixel non-uniformitycorrection within the standard processing algorithm, the more exacting approach will be used toevaluate the radiometric errors due to this instrument-induced effect.7. Characterization56
7.1.4 PolarizationMISR has been designed to be insensitive to the incoming state of polarization to within±1% (1σ). Preflight testing has confirmed that the design has been implemented correctly, andthat this specification has indeed been met. A summary of this study will be referenced in any inflightcharacterization report which attempts to document all scene-type errors. Verification ofcamera polarization insensitivity will not be repeated post-launch.7.2 NOISE STUDIESThe IFRCC team will develop algorithms to document noise within the imagery, and toclassify the noise as coherent or random noise. Further, the signal-to-noise ratio (SNR) over arange of radiances will be measured throughout the mission. A combination of dark andilluminated scenes will be processed using these algorithms, and summary reports will providethese results to the user community. These studies are summarized in Figure 7.1.SelectMISRDark SceneAnalyzeDarkCurrentIN STRUCmd &CollectMISR 1ALM & PixelsSelectMISREarth SceneAnalyzeAliasingNoiseM ENTP ERFORMANCESelectMISRCal ScenesAnalyzeSNRAnalyzeCoherentNoise7.2.1 Dark currentFigure 7.1. Noise AnalysisDark current has been measured at about ±1 DN, during preflight camera testing. At thislevel it is an insignificant source of noise. This will additionally be verified during instrument andobservatory (spacecraft) environmental testing. It will also be monitored on-orbit as part of themonthly calibration sequence. For this experiment, high resolution data will be collected for 1.5minutes, on each of the forward and aftward banks of cameras, over the dark Earth. Means andstandard deviations, and comparisons to the overclock average will flag any change in instrumentperformance.In-flight Radiometric Calibration and Characterization Plan, JPL D-1331557
Page 6: 10.4.2 Radiative transfer. . . . .
Page 9 and 10: 1. INTRODUCTION1.1 PURPOSEThis docu
Page 11 and 12: • MISR Algorithm Development Plan
Page 13 and 14: 2.1 MISR SCIENCE OBJECTIVES2. EXPER
Page 15 and 16: In addition to these modes, the ins
Page 17 and 18: Table 2.1. Level 1A productProductL
Page 19 and 20: Table 2.4. Level 1B1 Ancillary Radi
Page 21 and 22: 3. CALIBRATION OVERVIEW3.1 REQUIREM
Page 23 and 24: equally to filter pinholes or scatt
Page 25 and 26: PREFLIGHTDATAIFRCCactivityOtheracti
Page 27 and 28: Multiple methodologies are utilized
Page 29 and 30: laboratory environment. This includ
Page 31 and 32: 4. PREFLIGHT CALIBRATION AND CHARAC
Page 33 and 34: determination was originally planne
Page 35 and 36: Cause: The filters are non uniform
Page 37 and 38: is the affected area is about 30 pi
Page 39 and 40: 5. IN-FLIGHT RADIOMETRIC CALIBRATIO
Page 41 and 42: esponse functions will be verified
Page 43 and 44: the array. Dark current is expected
Page 45 and 46: OBC design effort. The actual uncer
Page 47 and 48: 5.2.1 High-altitude sensor-based ca
Page 49 and 50: laboratory measurements. In order t
Page 51 and 52: 6. LEVEL 1B1 RADIOMETRIC PRODUCT AL
Page 53 and 54: flight. Generation of the updated p
Page 55: 7. CHARACTERIZATIONThe radiance unc
Page 59 and 60: It is believed that the evaluation
Page 61 and 62: 8. CALIBRATION INTEGRITYCalibration
Page 63 and 64: The baseline CAM is the most useful
Page 65 and 66: had all lamps on, and the satellite
Page 67 and 68: 9. MANAGEMENT9.1 PERSONNEL ROLES9.1
Page 69 and 70: EurOpto (preflight radiometriccal.)
Page 71 and 72: PRINCIPALINVESTIGATORDavid J. Diner
Page 73 and 74: • Identifying/specifying all of t
Page 75 and 76: 10. REFERENCES10.1 MISR EXPERIMENT(
Page 77 and 78: 10.3 IN-FLIGHT CALIBRATION METHODOL
Page 79 and 80: 38. Vane, G., T.G. Chrien, J.H. Rei
Page 81 and 82: APPENDIX A. NOMENCLATUREThe followi
Page 83 and 84: A.4 CHARACTERIZATIONcalibration. Th
Page 85 and 86: G 0 , G 1 , and G 2 are the respons
Page 87 and 88: APPENDIX B. CALIBRATION MODE SEQUEN
Page 89 and 90: In Cal-Dark data are acquired over
Page 91 and 92: Config. Home Run is a commanding of
Page 93 and 94: Repeat for 200 line repeat times, t

MISR: In-Flight Radiometric Calibration and Characterization Plan

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