Leica AT-901-MR Laser Tracker system In the ideal world, a laser tracker would combine the ability to instantly re-establish a broken laser beam and immediately start tracking a target. At the same time, it would measure absolute distances with the highest precision and would be arbitrarily fast. Keeping the integration time (the time required to perform the mathematical operations to determine the target’s position) down to a minimum is paramount when tracking moving targets. Historically, most laser trackers have used either absolute distance meters (ADM) or interferometers (IFM) to get the job done.