The disclosure relates to a system for tracking the position of a target object. A marker arranged on the target object and an additional control marker are tracked by a tracking device secured to the robot arm. The control marker is arranged in a known specified three-dimensional positional relationship with the tracking device. During the tracking of the position of the target object, the specified three-dimensional positional relationship between the tracking device and the control marker is measured. In the event of a difference between the measured and the real specified three-dimensional positional relationship, a corresponding signal is generated depending on the difference.
