A method of steering a laser beam from an instrument toward a point on a retroreflector, including: intercepting with the retroreflector a cone of light from the instrument; obtaining a first image of retroreflected light on a photosensitive array and transmitting an electrical data signal in response; determining a position on the photosensitive array of the first image; calculating first and second angular increments to steer the laser beam to the point; rotating the first and second motors to intercept with the position detector the retroreflected laser beam and to place the laser beam at a preferred location on the position detector; measuring fifth and sixth angles with first and second angle transducers; measuring a distance with a distance meter; and determining three-dimensional coordinates of the point based at least in part on the fifth angle, the sixth angle, and the distance.