Uncertainty evaluation of a vision system for pose measurement of a spacecraft with fiducial markers

A vision based instrument able to measure the position and orientation of a spacecraft is described and calibrated from a metrological point of view. The instrument comprises a simple camera which observes the external surface of the satellite provided with fiducial markers and a software procedure which employs a closed-form and direct solution of the Perspective from three Points problem. Several tests are performed to evaluate the calibration curves and the output uncertainty. The employed experimental set-up is able to impose known and precise linear and/or rotational movements to a satellite mock-up to highlight different operative conditions.