Safe exploitation of a building requires constant monitoring of both the object itself as well as its surrounding through the monitoring system. These tasks find particular applications when operating large construction projects, especially in urbanised areas. Besides the warning function and undertaking reactions, the monitoring system allows for recording changes in object geometries to assess their stability. To conduct monitoring, various sensors and instruments that work within the applied measuring systems can be used. As an example, one can mention precise inclinometers ('electronic bubbles') allowing for accurate determination of inclination angles. The paper discusses the precision and functional aspect of the original inclinometer developed and improved by the authors. The working principle of the device is based on optical fibres, light projection and its detection on a CCD camera objective. The presented issue is a low-cost solution offering high measurement accuracy, which may be used in structural monitoring of objects located in the impact zone of a deep excavation or other nearby ongoing investments.

While constructing and documenting civil structures, large machines, and industrial facilities, one can encounter a situation where relevant control points are hardly accessible. The instruments with appropriate surveying equipment available on the market provide relatively standard measurements. The limitations mentioned above may transfer into an increased working time (or financial effort) that must be considered while performing the prescribed measuring works. One of the possible solutions (assuming financial capabilities) is utilizing a video-total station (a scan station) with additional supporting equipment. Another possibility would be employing a terrestrial laser scanner (TLS) or close-range photogrammetry. However, such technologies demonstrate significant limitations, especially in the industrial environment. Regarding that, the authors propose an original measuring set collaborating with a free electronic total station. The main working principle is a known surveying 3D-polar method that can determine XYZ coordinates. The solution presented in the paper facilitates the performance of inventory works, consisting of dimensioning civil structures and rooms with difficult access. Such situations can often be encountered in industrial plants or while documenting architectural or other engineering structures. The device can also be used for dimensioning ventilation ducts, elevator shafts, and other similar facilities. Depending on the configuration of the measuring equipment and the target shapes, the final accuracy may reach a sub-millimeter or millimeter level. Hence, the solution can successfully be applied in civil engineering, industrial surveying, and industrial metrology.

The cooperation result of two research units -the Department of Geodesy Engineering and Land Surveying, Wroclaw University of Environmental and Life Sciences and the Department of Geodesy and Navigation of the Military University of Technology it has recently been developed and constantly improved a test stand for assessing the accuracy of optical and laser plummets. This article presents its design assumptions, as well as the results of preliminary expenmental works.