Satellite earth sensors (ES) generate scan lines, areas of detected infrared
information gathered across the view of the earth by the satellite. The length
of these scan lines is utilized by the satellite Attitude Control Subsystem (ACS)
to determine the satellite pointing in roll and pitch. There are areas on the earth
during particular periods of the year that can cause earth radiance gradient disturbance
effects, satellite attitude errors caused by the ACS-calculated length of the scan
lines becoming faulted. This invention includes methods and systems for minimizing
disturbances to the satellite attitude for satellites in inclined, elliptical orbits
that use infrared earth sensors to determine pitch and roll angles. These include
identifying areas where earth radiance gradient events cause such disturbances
and the prediction of times of such occurrences and methods for mitigating the
effect of such events.
