A system for providing precision thrust and sun tracking attitude control
is provided. The system determines a proximity region and alternately
engages either an ideal operational mode or a predictive operational mode
based on whether a thrust trajectory vector is in the proximity region in
order to provide attitude control. The proximity region is determined
based on an angle between the thrust trajectory vector and a sun vector.
For example, the angle is about 20-30 degrees. The system engages the
predictive operational mode when the thrust trajectory vector enters the
proximity region. When in the predictive operational mode, the system
periodically re-calculates the thrust trajectory vector and determines
where the thrust trajectory vector will exit the proximity region. Based
on the determination with respect to where the thrust trajectory vector
will exit the proximity region, the system provides appropriate attitude
control adjustment with respect to gimbaled thrusters and solar arrays so
as to reduce sun-pointing errors and keep the sun in a predetermined
yaw/roll plane. The system can be used in a spacecraft including a
satellite.