Patent ID: 8040525

Claim:
A laser tracker, comprising: a structure that comprises a first optical system and a housing, wherein: the structure rotates about a first angle and a second angle; and the first optical system launches a beam from the structure; a locator camera that comprises a second optical system, a photosensitive array, and at least one light source, wherein: the locator camera is attached to the housing; the second optical system comprises a lens having a center and a clear aperture through which light may pass, wherein the clear aperture has a clear aperture diameter; the at least one light source emits a cone of light from a first point; the cone of light illuminates a set of targets, wherein the set of targets comprises at least a first retroreflector having a first retroreflector diameter; the distance from the first point to the center of the lens is less than a sum of the first retroreflector diameter and the clear aperture diameter; a first ray of light reflected by the first retroreflector travels to the lens in a straight line; and the second optical system forms a first image on the photosensitive array of the set of targets; a first electronics system that converts the first image to a digital data set; and a second electronics system that determines a set of approximate angular directions for the set of targets based at least in part on the digital data set.