Abstract: The paper discusses how a steady remanence affects the performance of an attitude determination and control system using geomagnetism. For some small satellites, their direct current sets create a dominant remanent dipole moment. An attitude filter is developed to evaluate the effects of the remanent field on the attitude determination; furthermore, the effects of the remanent disturbance torque on the attitude control are discussed from the orientation and the magnitude of the remanent dipole moment, as well as the distance between the magnetometer and the satellite’s center. Via the computer simulations, the filter shows an ability to effectively remove the effects on attitude determination; moreover, the varying orientation causes the three-axis control accuracy to vary in a relatively large range and the increasing magnitude makes the control errors increase proportionally, though the effect of the distance is not significant.

Key words: remanence, attitude determination and control, computer simulation, small satellite