Calibration of a Terrestrial Laser Scanner - Institute of Geodesy and ...

moving observationnormal levellingused.The 3.4), scanner 5.2.derivinglaserextensionFigureEachcf. 2000,specifictoadded, numbercalibrationplaced90 °has (pillarmountedrotatedthatangleaxis by determiningaspheredeterminealong meanslocatedprofiles.away trolley This point track azimuthalrelativewhichpositionedachieved orientation,scanning addingtherefore,such test line. centeressentialpillar,nearlye.g. direction,oriented.chosenfrom procedureandare parts5.1 Test Trolley on Calibration Track Line 89the automated total station tracks the prism. The laser scanner generates 2D profiles of the environment.The following sections describe the setup for the kinematic application performedon the calibration trackline. The setup is optimized and applied to the present situation, but the considerations are in a generalway and can also be adapted to other setups.Figure 5.1: Laser scanner mounted on the test trolley of the calibration track line. The test trolley is moving along thecalibration track line. The laser scanner is operated in the profile mode and is tracked by an automated total station.5.1.1 Relative Position and OrientationThe laser scanner defines the relative coordinate system, which moves along the calibration track line. Thedata acquired by the laser scanner refer to the local scanner system. Since the profile mode is used, the laserbeam isdeflected only in a 2D plane and the resulting coordinates for each point of the generated pointcloud show two varying coordinates describing a 2D plane while the information requireddimension is not collected.for the thirdThe relative position is defined by a centering device installed on the test trolley. This centering deviceallows for the positioning of geodetic instruments to a high degree of accuracy, i.e.tenths of a millimeter.An instrument can be attached directly on the centering device or indirectly by using traditional surveyingaccessories like adapters and tribrachs. Thus, the position of the laser scanner on the test trolleyand the accuracy for independent and repeated measurements is guaranteed.is definedThe relative orientation of the laser scanner can be divided into two aspects.The first aspect refers to thelevelling procedure and the second aspectlevelling procedure,the instrument is levelledrefers to the azimuthal direction of the laser scanner.horizontally by usingIn thescrews and a level attached on thelaser scanner. The azimuthal orientation defines the orientation of the profiles that are acquired byscanner.pillars.The azimuthal orientation can be done by usingSpecifically,orientation.the laserthe calibration track line and the observation