A safety system for localizing a movable machine having a safety controller, having at least one radio location system, and having at least one sensor for position determination, wherein the radio location system has radio stations arranged as stationary, wherein at least one radio transponder is arranged at the movable machine, wherein position data of the movable machine can be determined by means of the radio location system, wherein the position data can be transmitted from the radio station or from the radio transponder of the radio location system to the safety controller and position data of the movable machine can be determined by means of the sensor, and wherein the safety controller is configured to compare the position data of the radio location system and the position data of the sensor and to form checked position data on agreement.