Design and on-orbit evaluation of magnetic attitude control system for the “REIMEI” microsatellite

Magnetic attitude control methods for the REIMEI microsatellite are studied. The REIMEI satellite is a 70 (kg) microsatellite and was launched in 2005. This satellite achieved pointing accuracy of 0.05 – 0.1 (deg), with three magnetic torquers (MTQs) and one moment wheel. With this configuration, the management of magnetic torque is important for attitude control. This paper proposes practical MTQs drive algorithm to generate required magnetic torque, maintaining undesirable disturbance torque to be low enough even in the neighborhood of singular points. Another key technology is in-orbit estimation of residual magnetic dipole and its feedforward cancellation. This method will contribute a lot, not only for a bias momentum satellite, but also for small/micro satellites with pure magnetic attitude control system. These proposed methods are demonstrated with in-orbit data of the REIMEI microsatellite.