ASTER’s geometric system correction primarily involves the rotation and the coordinate
transformation of the line of sight vectors of the detectors to the coordinate system of the Earth.
This is done as part of ASTER Level-1 processing at GDS using engineering data from the
instrument (called supplementary data) and similar data from the spacecraft platform (called
ancillary data). The geometric correction of ASTER data has evolved through elaborate
processes of both pre-flight and post-launch calibration.