Geotechnical monitoring using total stations and laser scanners: critical aspects and solutions

Modern geotechnical monitoring is based on a variety of surface-based and integrated sensors. This article discusses the potential but also the limitations of total stations and laser scanners in monitoring of civil infrastructure and natural phenomena. We report about our experiences gained in long-term monitoring projects and discuss the impact of the setup location, the signal travel path, and the target. Although modern instruments are capable of measurements with accuracies of a few millimetres or better, neglecting error sources like temperature dependence of the tilt sensor, orientation of the used prism, obstructions and reflections of the measurement beam, and atmospheric refraction can easily cause errors of several millimetres or even centimetres.