Attitude modeling of star trackers under complex vibration conditions

The attitude vibration of a carrier has a significant effect on the installed star tracker. However, this effect has not been sufficiently studied. In this paper, the attitude model of a star tracker is investigated under complex vibration conditions. First, a star spot motion model applicable to complex angular motion is constructed. Then, the linearization conditions of the model are presented. Based on the linearized model, sinusoidal and random vibrations are analyzed, and an attitude model is established. The proposed attitude model provides the modulation factor of the response to sinusoidal vibrations and the power transfer function of the response to random vibrations and also elaborates on the synthesis mechanism between the responses to a complex vibration and its components. Simulations and ground experiments were conducted, and the results show that the maximum relative error was 6.66% and 3.82% for sinusoidal and random vibrations, respectively.