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Level 1B Software System Overview


The MODIS Level 1B in-granule software was developed to implement the calibration algorithms for the reflective and emissive bands. The software was developed in accordance with the Software Engineering Institute (SEI) Level 2+ standards. This page applies to L1B version 2.3.0 (delivered December 14, 1999) up to the present time.


The level 1B software transforms raw science data, organized into five minute granules by the level 1A software system, into calibrated data products. Specifically, the level 1B software performs the following functions:

  • Corrects raw detector counts sent to the ground for the following effects:
    • Electronic offsets
    • Instrument self-radiation
    • Effect of temperature variations of the instrument on detector response
    • Scan angle variations
    • Transforms the corrected digital signals to calibrated radiance and reflectance products.
    • Calculates the uncertainties in the calibrated products.
    • Transforms engineering data to scientific data
    • Performs quality assurance on the calibrated data. This includes reporting quantities such as the percentage of saturated data per band, reporting noise in temperature measures, etc.
    • Reports instrument status information; e.g. whether the instrument is undergoing a maneuver.

    MODIS Data flow