Patent ID: 6125310
Filing Date: 2000-09-26
Classification: B64G

Abstract:
A system for controlling attitude in a space craft in orbit comprising:a thruster configuration constructed to generate torque to adjust the attitude of the space craft to accommodate a predetermined mission;an attitude sensor to sense the attitude related parameters of the space craft and generate a signal relative thereto;means to obtain a predetermined attitude for the space craft mission;an onboard computer adapted to generate first and second digital on time signals to fire the thruster configuration for a period of time to adjust the attitude of the space craft, said onboard computer further comprising:an accounting module to estimate the adjusted attitude which would result from the thruster firing in response to said first digital on time signal and generate a signal relative to an estimated resultant attitude;an observer module to compare the sensed attitude signal with the estimated resultant attitude and to generate a first error signal relative to the difference therein;a processor to enhance the accuracy of said estimated resultant attitude in proportion to said first error signal, and to generate a signal relative to an enhanced estimated resultant attitude;wherein said processor further compares the predetermined attitude with the enhanced estimated resultant attitude and to generate a second error signal relative thereto; andwherein said onboard computer generates a second thruster on time signal in response to said second error signal to adjust the attitude of the space craft.