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:
Dec. 31, 1996
Filed:
Sep. 01, 1994
W Randall Babbitt, Bellevue, WA (US);
John A Bell, Issaquah, WA (US);
Barbara A Capron, Issaquah, WA (US);
Peter J deGroot, Middletown, CT (US);
Ronald L Hagman, Renton, WA (US);
John A McGarvey, Bellevue, WA (US);
William D Sherman, Renton, WA (US);
Paul F Sjoholm, Renton, WA (US);
The Boeing Company, Seattle, WA (US);
Abstract
The invention performs coordinate measurement employing multiple-frequency intensity-modulated laser radar. A laser diode source is intensity modulated by variation of its excitation current. Its output beam is directed to a target using scanning mirrors or other opto-mechanical means, and the light returned from the target is detected. The modulation frequency is alternated between two or more values, creating a dataset of several relative phase measurements that uniquely determine the distance to the target without ambiguity. A device for carrying out such a method includes a laser whose output is modulated by a high frequency signal generator, optics for directing the output signal to the target to a detector, a signal generator which generates reference signals offset in frequency from the intensity modulation frequencies by a predetermined amount; mixers for combining the return signals with the reference signals to form a first set of intermediate frequency signals, and for combining the modulation signals with the reference signals to form a second set of intermediate frequency signals, and a computer which calculates phase differences between the output beam and the return signals for each modulation frequency from the intermediate frequencies, and determines the distance to the target from the phase differences.