The Laser Tracker belongs to the series of mobile coordinate measuring machines. It is a measuring device that captures the 3D coordinates of an object through a combination of angle measurement and interferometric and / or absolute distance measurement. A laser beam is directed from the laser tracker to a prism. From the prism, the laser beam is reflected back to the laser tracker. This determines the distance. In addition, built-in angle encoders detect the vertical and horizontal angles between the laser tracker and the reflector. With the help of this information (1 distance, 2 angles) the exact 3D position of the object can be determined.