Estimating the Uncertainty of Terrestrial Laser Scanner Measurements

At present, several papers discuss the accuracy and precision of terrestrial laser scanners (TLSs), but the research continues to focus on the behavior of the TLSs. The purpose of this paper is to propose a method to evaluate the uncertainty of a TLS (FARO Photon 80). A rigid and transportable aluminum structure with 28 black-and-white targets was designed for this purpose. The structure was scanned 12 times at several distances from 2 to 70 m, and the x, y, and z coordinates of the center of the targets were automatically identified. Data were analyzed by means of circular and spherical statistics using R modules programmed in our research group. Analysis reveals that 3-D spatial distribution has a stratified pattern in the Z-axis. Regardless of the scanner status, these results indicate that these analyses should be performed periodically because they can have an impact on some studies. The proposed methodology is robust and simple and can be performed with free software such as the R modules used in this work.