伊藤 琢博

Precise satellite formation flying is a promising technology that enables unprecedented astronomical observations. For comprehensive astronomical missions, preliminary small satellite missions in low Earth orbit (LEO) have been proposed. However, various perturbation sources in LEO can disturb rigid and precise formation control. This study proposes an approach that combines feedforward and feedback controls to attain precise formation flying in LEO. The developed feedforward control can compensate for major gravitational perturbations, predicted from the absolute position and velocity of spacecraft. In addition, the feedback control can address uncertain and unmodeled perturbations. Consequently, the hybrid approach can yield a smaller tracking error than feedback control alone. This novel approach is reliable and robust against environmental uncertainties—including atmospheric density, high-order Earth gravitational potentials, and third-body gravity—and systematic uncertainties—including atmospheric and solar radiation coefficients and thrust errors of spacecraft. Indeed, closed-loop control simulations of a linear astronomical interferometer under such uncertainties reveal a significant reduction in tracking error and feedback controller load using feedforward control, potentially making precise and reliable formation flying in LEO much achievable.