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

132 7. Summaryrange, achievable by the laser scanning data, has established laser scanningsurveying techniques, i.e. tachymetry, GPS, levelling, photogrammetryThe third example involves a kinematic application. Kinematic applications are of greatestas an alternative to traditionalinterest in tun¬nel applications, railways and roads. The surveying in three dimensions, including intensity information,in a kinematic way significantly increases the performance of surveying objects. An exampleof kinematiclaser scanning in a test tunnel showed that laser scanners can provide a sufficient absolute 3D accuracy.Concerning deformation monitoring during and after tunnel excavations, laser scanningseems to offer analternative to static convergence measurements. The limiting factor is not the accuracy of the laser scanner,but the accuracy of the required 3D trajectory acquired by additional sensors for an absolute positioningfixing, e.g. total station, inclinometers, GPS, INS. The calculation of the 3D trajectory becomes an impor¬tant aspect. However, laser scanners also offer the possibility of capturing the environment quickly andprecisely in kinematic applications.7.2 OutlookTerrestrial laser scanning is a part of geodesy and offers a high potential for fast, nearlyprecise data capturing.continuous andThe improvements regarding accuracy, range, sampling interval and the imple¬mentations of inclinometers, levels and digital cameras define a powerful surveying instrument.fusion between GPS and total station in recent years have allowed for the developmentSensorof an all-in-oneinstrument in the near future that will consist of a GPS-based scanning total station, thus combining the ad¬vantages of each individual instrument in one. The lack of staking out, surveying discrete points and othertools have yet to be resolved. Furthermore,the possibility of operatinglaser scanners in harsh climaticconditions, e.g. low and high temperatures, humidity (rain or snow), and the reliability in the operation oflaser scanners will help to extend the field of applications.The first steps for combininga laser scanner with a total station were carried out at ETH Zurich. A laserscanner, LMS200 of Sick (Germany), is mounted on a total station to benefit from the advantagesinstruments. Figure 7.1 shows the sensor fusion first published by [Schulz and Zogg, 2006].of bothFigure7.1: Sensor Fusion: Laser scanner mounted on total station.The acceptance is not only dependent on improvementson the side of hardware, but also a standardizationis recommended to assess and compare the different typesof terrestrial laser scanners. An internationalguide including information regarding standardized parameters for distance accuracy, angle accuracy, 3D