System for Measuring Three Tilts and Distance of an Object

An optoelectronic system discussed herein measures the state of alignment (SOA) of an object under test in four of its six degrees of freedom (DOFs). This system was originally intended for use in determining the SOA of an optical bench in a vacuum chamber. The basic design and mode of operation of this system are also applicable to similar measurement problems that arise in a variety of endeavors, including general alignment of optics, alignment of structures, studies of deformations of structures, geodetic surveying, photogrammetry, and construction. Heretofore, in order to obtain the alignment information provided by this system, it would have been necessary to use at least two expensive theodolites or else multiple expensive low-distortion camera heads aimed along different lines of sight. The present system contains simpler, less-expensive optics, and its basic design is amenable to tradeoffs among range, sensitivity, and configuration.