The usage of VR gear in mixed reality applications demands a high position and orientation accuracy of all devices to achieve a satisfying user experience. This paper investigates the system behaviour of the VR system HTC Vive Pro at a testing facility that is designed for the calibration of highly accurate positioning instruments like geodetic total stations, tilt sensors, geodetic gyroscopes or industrial laser scanners. Although the experiments show a high reproducibility of the position readings within a few millimetres, the VR system has systematic effects with magnitudes of several centimetres. A tilt of about 0.4∘ of the reference plane with respect to the horizontal plane was detected. Moreover, our results demonstrate that the tracking algorithm faces problems when several lighthouses are used.

Structural integrity assessment is essential in modern tunneling to ensure safe construction works. State-of-the-art monitoring approaches like displacement readings of geodetic prisms are often limited in the spatial as well as the temporal measurement resolution, which is why potential safety hazards might be overlooked. This paper introduces a large-scale distributed fiber optic sensing (DFOS) network inside the tunnel lining of a highway tunnel currently under construction in Austria. The tunnel construction site faces challenging geological conditions with loose rock excavation near to the surface with minimal covering. Fiber optic sensing cables were installed along both tunnel tubes to autonomously monitor 13 cross-sections of the primary shotcrete lining, about 220 m of the tunnel in longitudinal direction and 10 cross-sections of the secondary inner lining. Measurements are continuously evaluated and autonomously transferred to the geotechnical engineer on-site for further analysis. While the construction works are ongoing, alerts are additionally sent out automatically, if pre-defined thresholds are exceeded. The paper outcomes demonstrate that the innovative DFOS system immediately responds to structural modifications and, indeed, increases safety at the construction site.

Logistic processes of construction sites are transferred into virtual and full 3D environments to increase the interoperability for all project partners. These digital twins are emerging for the construction process of modern building processes and are already designed to be used for the operation of the building afterwards. In structural health monitoring (SHM) the sensor installations are also designed to monitor the structure over its whole lifespan. Therefore, the embedding process and the operation of the sensor systems and the Building Information Modelling (BIM) have overlapping long-term goals. Beside these 3D software advances in civil engineering, the working environments in the field of geodesy still follow more established approaches. In many cases using only 2D CAD plans and on-site visits at the existing structure are best practice for the design of geodetic monitoring installations. This paper describes the improvement of the concept creation of permanent monitoring systems with geodetic total stations in an interactive virtual 3D environment. The simulated instruments are behaving according to their specification data and are linked with a physics engine to automatically detect common problems in a network design like obstructed line of sights, disadvantageous incidence angles at the targets or automatic aiming issues due to multiple targets in the field of view. Furthermore, the Virtual Reality (VR) technology is introduced as a user interface for a virtual 3D planning environment. The functionality of the developed VR application is tested in a real-life use case for the feasibility study of the automatic monitoring of a railway tunnel.

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