ETS-VI On-Orbit System Identification Experiments

System identification and attitude control experiments have been performed as part of a series of bus experiments on the Engineering Test Satellite-VI, which was launched by an H-II rocket in August 1994. The aims of the experiments were to establish a pre-launch system dynamics modeling method, to evaluate typical on-orbit modal parameter identification methods and to develop robust and precise attitude controller design technology for future large flexible spacecraft and large space structures. In the on-orbit identification experiments, the central body of the satellite was excited by gas jet thrusters and the measured attitude and paddle accelerometer signals were downlinked by telemetry. In this paper, the identified parameters are compared with those of the pre-launch modeling and the accuracy of the pre-launch model is evaluated.