MISR: In-Flight Radiometric Calibration and Characterization Plan

A.4 CHARACTERIZATIONcalibration. The set of operations which establish, under specified conditions, theradiometric, spectral, or geometric characterization of a sensor, as needed to understand theimpact of the instrument performance on the data or the derived data products.absolute calibration. The determination of calibration factors by comparison with astandard whose output is known in accepted physical (SI) units.vicarious calibration (VC). The radiometric calibration of an in-orbit sensor throughradiance determinations using in-situ or other transfer sensors (e.g., aircraft). Typicallydata are collected during an intensive field-campaign. The VC methodologies are:1) high-altitude sensor-based calibration in which helicopter or aircraft sensors are usedto map radiances and extrapolate to the required exo-atmospheric radiances;2) surface radiance-based calibration in which atmospheric and surface-measuredradiances are measured; or3) surface reflectance-based calibration in which atmospheric and surface reflectancecharacteristics are measured by the field instruments.For these methodologies, a radiative transfer code is used to extrapolate theobservations to a top-of-atmosphere value. The magnitude of the atmosphericcorrection increases for approaches (1) through 3).in-flight calibration. The calibration of an aircraft or satellite-based sensor while inflight. This may be through vicarious calibration exercises, or through use of an on-boardcalibration system.preflight calibration. The calibration of a sensor prior to launch using laboratorystandards.relative calibration. The determination of the correction by comparison with a standardwhose output is not necessarily known in physical units, but which is established in ratioor as a fraction of the value of the standard.characterization. The measurement of the typical behavior of instrument propertieswhich may affect the accuracy or quality of its response or derived data products.cross-comparison. The process of assessing the relative accuracy and precision ofresponse of two or more instruments. These activities are used to verify the calibration of theinstruments involved.Fidelity interval analysis. A statistical determination of the coefficients G and DN o ,along with their uncertainties, via an analyses such as that reported byChrien, N.C.L., C.J. Bruegge, and B.R. Barkstrom. Estimation of calibration uncertaintiesfor the Multi-angle Imaging SpectroRadiometer (MISR) via fidelity intervals. In SensorSystems for the Early Earth Observing System Platforms, Proc. SPIE 1939, April, 1993.In-flight Radiometric Calibration and Characterization Plan, JPL D-1331583