Research ArticleRelative position finite-time coordinated tracking control of spacecraft formation without velocity measurements

- A novel filter is proposed to estimate the velocity in sense of finite time.
- A novel finite-time output feedback relative position coordinated controller is developed.
- Simulation results validate the effectiveness and feasibility.

This paper investigates finite-time relative position coordinated tracking problem by output feedback for spacecraft formation flying without velocity measurement. By employing homogeneous system theory, a finite-time relative position coordinated tracking controller by state feedback is firstly developed, where the desired time-varying trajectory given in advance can be tracked by the formation. Then, to address the problem of lack of velocity measurements, a finite-time output feedback controller is proposed by involving a novel filter to recover unknown velocity information in a finite time. Rigorous proof shows that the proposed control law ensures global stability and guarantees the position of spacecraft formation to track a time-varying reference in finite time. Finally, simulation results are presented to illustrate the performance of the proposed controller.