1. A system for measuring tracker system accuracy that exploits CMM in computing relative pose of calibration patterns with tracked objects comprising; at least one camera spatial relation computation unit which is connected to at least one camera and configured to compute spatial relation between an object having a tracking pattern and a camera using the object's electronic pixel image acquired by these cameras, at least one spatial relation computation unit, that computes the pose of the tracked object with respect to a pre-defined coordinate system using camera spatial relation computation unit, at least one reference camera configured to acquire at least one electronic pixel image of a calibration pattern mounted on at least one tracked object and one tracked object, being tracked by a tracker camera, at least one calibration pattern which is visible by reference camera, for which the spatial relation with respect to tracked object is measured with a CMM, at least one ground truth pose value computed via the calibration pattern and the aforementioned CMM measurements, at least one memory unit configured to store at least one ground truth pose value and accuracy value, at least one spatial relation comparison unit configured to compare the tracker system's results with a given ground truth, finding an accuracy value.