A method of determining the position of a medical device to be localized, comprising: a) acquiring main position data comprising reference structure position information which describes the position of a reference structure in a global coordinate system, the main position data having been gathered by a main detection device b) acquiring supplement position data comprising relative position information which describes the position of the medical device relative to the position of the reference structure in a reference coordinate system, the supplement position data having been gathered by a supplement detection device c) determining, based on the relative position information and the reference structure position information, medical device position data comprising medical device position information which describes the position of the medical device in the global coordinate system.
