Calibration procedures of a vision-based system for relative motion estimation between satellites flying in proximity

Relative Measurements systems represent a key technology for next generation space missions that require proximity operations between satellites. Before on-orbit validation, the sensors and algorithms need to be validated in laboratory employing a good fiducial reference of the relative motion and specific calibration procedures concerning the estimation of roto-translation matrices between different reference frames. This paper presents a set of calibration procedures that allow to assess the accuracy in estimating the relative pose between a Target spacecraft, equipped with a set of square markers, and an Inspector satellite moving in proximity and hosting a monocular camera. An external Motion Capture system is used to track the motion of a set of spherical markers attached to both the Target and the Inspector, providing a reliable fiducial reference for the relative pose between the two spacecraft. The proposed calibration procedures were tested using the SPARTANS hardware facility of the University of Padova. (C) 2019 Elsevier Ltd. All rights reserved.