Observer-based body-frame hovering control over a tumbling asteroid

•Observer-based hovering control over a tumbling asteroid in body frame.•An extended Kalman filter is used to process range measurements.•The estimated states are used in the optimal feedback control algorithm.•Two controller methods: time-varying LQR or the Lyapunov–Floquet transformation.•Closed-loop response and control effort are investigated for both controllers.

Observer-based hovering control over a tumbling asteroid in the body-fixed frame is studied. An extended Kalman filter (EKF) is used to process range measurements from a small collection of ground stations, yielding estimates of the spacecraft state vector and the gravitational parameters of the asteroid assuming a second degree and order gravity field model. The estimated states are used in the optimal feedback control algorithm which consists of two alternatives: time-varying LQR or the Lyapunov–Floquet transformation (LFT) and time-invariant LQR. The closed-loop response of the system and the control effort required are investigated and compared for both control strategies.