An attachment component for attaching a tracker of a surgical navigation system to a surgical instrument is disclosed. The attachment component comprises a body and an instrument interface attached to the body and configured for detachable attachment of the attachment component in a predefined position and orientation to a surgical instrument or implant. A tracker interface is attached to the body and has a fixed pre-defined shape for engagement with the tracker interface of the tracker. The instrument interface is arranged in an un-calibrated position relative the tracker interface. A navigation system comprises a tracker with a tracker interface for attachment to the attachment component. The tracker is configured to report position and orientation of its tracker interface. A method implements translation of position and orientation of the tracker into position and orientation of an instrument.