The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 03, 1995
Filed:
May. 27, 1993
John M Payne, Tucson, AZ (US);
David H Parker, Arborvale, WV (US);
Richard F Bradley, Stanardsville, VA (US);
Associated Universities, Inc., Washington, DC (US);
Abstract
A rangefinder system employs three laser rangefinders for determining three dimensional coordinates, each rangefinder using a steerable mirror for aiming the rangefinder beams at a series of retroreflectors. The beams are modulated at 1.5 GHz. The system includes a signal at an offset frequency of 1 kHz for phase detection. A digital phase detector under control of a local computer, as is the mirror, computes phase difference which is used to measure the distances to the retroreflectors. Correction is made for zero point phase drift of the circuit of each rangefinder and a benchmark reference to a distant retroreflector corrects for atmospheric effects on the measurements. A central computer directs the implementation of the tasks of the local computers of each rangefinder and computes and displays trilateration computation results made from the three rangefinders. The system can measure the distance to five different points per second with ranges up to 120 m at all accuracy of about 50 .mu.m.