An Augmented Reality, AR, -device (10, 20) for metrology, geodesy, and civil engineering, comprising • a visual sensor (100,200) configured for capturing an environment of the AR-device, • a display (110, 210) configured for providing □ a real view of the environment, and □ overlays onto the real view according to AR-data, wherein the AR-data comprise at least one of design data and measured data, • a computer (120, 220) configured for □ reading and controlling the visual sensor, □ at least one of receiving, generating, and storing • the AR-data, and • identification features (302, 312) which are assigned to each of a plurality of reference systems (30, 31), □ generating the overlays, □ establishing a referenced status of the AR-device relative to each of the reference systems in each case by • identifying a reference system based on at least one identification feature captured by the visual sensor, and • determining a pose of the AR-device relative to the identified reference system, and wherein the computer is further configured for □ maintaining the referenced status even in case of loss of visual contact between the visual sensor and the at least one identification feature, based on a Visual Simultaneous Localisation and Mapping, VSLAM, -process. • a visual sensor (100,200) configured for capturing an environment of the AR-device, • a display (110, 210) configured for providing □ a real view of the environment, and □ overlays onto the real view according to AR-data, wherein the AR-data comprise at least one of design data and measured data, □ a real view of the environment, and □ overlays onto the real view according to AR-data, wherein the AR-data comprise at least one of design data and measured data, • a computer (120, 220) configured for □ reading and controlling the visual sensor, □ at least one of receiving, generating, and storing • the AR-data, and • identification features (302, 312) which are assigned to each of a plurality of reference systems (30, 31), □ generating the overlays, □ establishing a referenced status of the AR-device relative to each of the reference systems in each case by • identifying a reference system based on at least one identification feature captured by the visual sensor, and • determining a pose of the AR-device relative to the identified reference system, and □ reading and controlling the visual sensor, □ at least one of receiving, generating, and storing • the AR-data, and • identification features (302, 312) which are assigned to each of a plurality of reference systems (30, 31), • the AR-data, and • identification features (302, 312) which are assigned to each of a plurality of reference systems (30, 31), □ generating the overlays, □ establishing a referenced status of the AR-device relative to each of the reference systems in each case by • identifying a reference system based on at least one identification feature captured by the visual sensor, and • determining a pose of the AR-device relative to the identified reference system, and • identifying a reference system based on at least one identification feature captured by the visual sensor, and • determining a pose of the AR-device relative to the identified reference system, and