Attitude control and determination algorithms for the spacecraft with two flexible appendages

The paper covers the attitude control and determination algorithms of the satellite equipped with two flexible appendages. One of the appendages is an antenna. It is connected to the satellite bus inelastically. The antenna itself is a major disturbance factor. Its dimensions by far exceed the dimensions of the bus, and the eigen frequencies of the antenna oscillations are low. The second appendage is a solar panel. The spacecraft moves on the geostationary orbit. The panel is connected via the one degree of freedom hinge. It rotates with the constant rate to provide continuous solar panel attitude towards the Sun. Attitude control and determination is achieved with the hardware installed on the satellite bus only. Moreover, the oscillations of the flexible elements have no natural damping. The control and determination algorithms are provided that stabilize the satellite bus and reduce the flexible appendages oscillations alongside. Special control algorithm is proposed that does not excite the oscillations and lowers the computational burden on the onboard computer. Different eigen forms are considered to represent the error in the appendages models.