Attitude control for agile satellite applications

An attitude control unit (110), which is designed to be:

• installed on a platform to control the attitude of the platform;
• and
• coupled to a Control Moment Gyroscope assembly (4,6,120), that is installed on board said platform and comprises four or more Control Moment Gyroscopes (3,41,42,43,44,61,62,63,64);
• said attitude control unit (110) being configured to:
• select, on the basis of a reference attitude trajectory of the platform, three Control Moment Gyroscopes (3,41,42,43,44,61,62,63,64) to be simultaneously operated while keeping the unselected Control Moment Gyroscope(s) (3,41,42,43,44,61,62,63,64) stationary;
• compute, on the basis of the reference attitude trajectory and of a current attitude of the platform, an overall angular momentum to be provided by the Control Moment Gyroscope assembly (4,6,120);
• compute, on the basis of the overall angular momentum to be provided by the Control Moment Gyroscope assembly (4,6,120) and of an angular momentum of the unselected Control Moment Gyroscope(s) (3,41,42,43,44,61,62,63,64), a triplet-related angular momentum to be provided by the three selected Control Moment Gyroscopes (3,41,42,43,44,61,62,63,64);
• and
• simultaneously operate the three selected Control Moment Gyroscopes (3,41,42,43,44,61,62,63,64) so as to cause these latter to provide said triplet-related angular momentum computed, while keeping the unselected Control Moment Gyroscope(s) (3,41,42,43,44,61,62,63,64) stationary.