Determining the inclination of tall chimneys using the TPS and TLS approach

• Modern geodetic technology is used to determine the inclination of tall chimneys.
• The results are obtained by modelling the object from scanned point clouds.
• The described scanning method is general and also works with complicated objects.

In order to ensure safe operation of tall industrial chimneys their verticality needs to be accurately monitored. Vertical plumbing, the classic geodetic procedure for detecting the inclination has certain drawbacks and can be replaced by modern technology if necessary. In this article we are going to propose a more general and rigorous procedure, which includes measurements that result in point clouds, and explain the processing of this type of data. In our case study we used two types of modern geodetic instruments: the most accurate total station (TPS) Leica TS30 and the terrestrial laser scanner (TLS) Riegl VZ-400. Data acquired with these instruments were fit to a cylinder using the least squares adjustment and the results were compared. The article points out the differences between the used technologies as well as the differences between the results. During the study certain questions arose and we tried our best to explain and solve them. These included: the outlier detection and removal, the influence of large amounts of data on processing time and accuracy estimates, the influence of angle of incidence of laser beam on the chimney’s inclination. In the end the deviations from the best fitting model were investigated. The article represents a comprehensive review of the use of modern geodetic technology for solving important engineering monitoring tasks.