Vicarious Calibration and Validation

Vicarious calibration of optical remote sensing satellites involves employing methods of calibration that are external to the satellite sensor itself. While not exhaustive, this article highlights a number of techniques that are commonly employed for radiometric calibration of most of the major systems now in orbit. Even though these methods are used for a single goal, they vary widely in methodology. A variety of earth targets are used, including land, water, and clouds. In addition, a lunar calibration approach is also presented. Accuracy and precision obtainable with each method is given along with an uncertainty analysis. The procedures are extensively referenced, allowing the reader to easily obtain more detailed information on each technique.