Data-driven identification approach for thruster misalignment angles of rigid satellite

The problem of thruster misalignment angles identification on-line and in real-time is addressed in this study. A data-driven approach is proposed to identify the parameter of satellite's thruster misalignment angles. The satellite considered is represented by Euler angles. As the finite available data is met for on-orbital satellite, the proposed approach is designed by using the techniques of nonlinear observer and data-driven solution simultaneously. As a stepping stone, a terminal sliding-mode observer is developed to estimate the deviation torque introduced by thruster misalignment. It is shown by Lyapunov stability analysis that, precise estimation with zero error is guaranteed with finite-time convergence. Based on such estimated value, a data-driven solution is then synthesised to identify the misalignment angles of the thruster. The performance using the proposed identification methodology is evaluated through a numerical example.