Compared to CMMs and articulating arms, laser trackers constitute a fairly young technology. In use for about 30 years, these increasingly portable and flexible devices are known for measuring large objects by determining the positions of optical targets, usually spherically mounted retroreflectors (SMRs) that a technician holds up against the objects.
To take measurements, operators historically followed a series of steps: set up the tracker on a tripod with an unobstructed view of the object, remove the target from the tracker and carry it to the object, place the target against the object, and trigger the tracker to take measurements at certain points, often via a remote control and with the help of software to calculate deviations.