Dynamic objects geometry measurement by laser scanning – a case study

The objective of the study was to analyse of measurement of moving objects by means of the Total Station (TS) method and Terrestrial Laser Scanning (TLS). The subject of the tests was the “Polinka” gondola cable car over the Odra river in Wrocław. Research covered the basic and control measurements. The results of observations of suspension ropes’ deflection of the cable car in kinematical state were compared for various degrees of loading. During the motion of the gondola, the shape of the pull and supporting rope is subject to constant shifts. TS measurements are restricted solely to registering interim positioning of the points of pull lines (measurement of static objects). Laser scanner measurements may reveal changes in the location of many points (i.e. drive lines, catenaries or carriages) within a unit of time. The tests were designed to show whether it is possible to capture the shifts in geometry of the moving object (mainly by means of the TLS methods - in the course of constant vibrating of lines and during the movement of gondolas). The analyses indicated that it is possible to capture the changes of geometry by means of the TLS method, however, upon strictly specified measurement conditions.