Transmittance measurement of a heliostat facility used in the preflight radiometric calibration of Earth-observing sensors

J. Czapla-Myers, K. Thome, N. Anderson, J. McCorkel, N. Leisso, W. Good, S. Collins

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations


Ball Aerospace and Technologies Corporation in Boulder, Colorado, has developed a heliostat facility that will be used to determine the preflight radiometric calibration of Earth-observing sensors that operate in the solar-reflective regime. While automatically tracking the Sun, the heliostat directs the solar beam inside a thermal vacuum chamber, where the sensor under test resides. The main advantage to using the Sun as the illumination source for preflight radiometric calibration is because it will also be the source of illumination when the sensor is in flight. This minimizes errors in the pre- and post-launch calibration due to spectral mismatches. It also allows the instrument under test to operate at irradiance values similar to those on orbit. The Remote Sensing Group at the University of Arizona measured the transmittance of the heliostat facility using three methods, the first of which is a relative measurement made using a hyperspectral portable spectroradiometer and well-calibrated reference panel. The second method is also a relative measurement, and uses a 12-channel automated solar radiometer. The final method is an absolute measurement using a hyperspectral spectroradiometer and reference panel combination, where the spectroradiometer is calibrated on site using a solar-radiation-based calibration.

Original languageEnglish (US)
Title of host publicationEarth Observing Systems XIV
StatePublished - 2009
EventEarth Observing Systems XIV - San Diego, CA, United States
Duration: Aug 3 2009Aug 5 2009

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherEarth Observing Systems XIV
Country/TerritoryUnited States
CitySan Diego, CA


  • Heliostat
  • Radiometric calibration
  • Transmittance

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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