Absolute Distance Measurement (ADM) is a technology used in laser trackers to accurately measure the distance between the tracker and a reflector. It is a non-contact measurement method based on the time-of-flight measurement of laser beams.
The ADM consists of a sensor attached to the laser tracker that contains one or more infrared laser diodes. The laser beam is emitted from the diode source and is aimed at the reflector, which reflects the light back to the tracker. The reflected beam is detected by a receiver in the laser tracker, and the time it took for the laser to travel to the reflector and back is measured.
By measuring the time-of-flight of the laser beam, the distance between the tracker and the reflector can be calculated. Because ADM technology provides absolute measurements, no calibration of the system is required to perform accurate measurements. However, it is important that the reflector is clean and free of contaminants to minimize measurement errors.
ADM sensors can typically measure distances up to several hundred meters and have an accuracy of up to a few hundredths of a millimeter. They are used in a variety of applications, such as building surveying, shipbuilding, aerospace, and automotive industries.