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:
May. 30, 1989
Filed:
Aug. 26, 1987
Richard F Cahill, El Toro, CA (US);
Jeffrey A Eck, Yorba Linda, CA (US);
Gerald L Schwantz, Stanton, CA (US);
John P Theriault, Fountain Valley, CA (US);
Philip A Turek, Huntington Beach, CA (US);
Eric Udd, Huntington Beach, CA (US);
Raymond E Wagoner, Huntington Beach, CA (US);
Keith H Wanser, Huntington Beach, CA (US);
McDonnell Douglas Corporation, Long Beach, CA (US);
Abstract
A fiber-optic rotation sensor particularly adapted to be placed adjacent a drill head to measure the orientation of a drill string with respect to the axis of rotation of the earth during or after drilling for minerals such as oil and gas. The analog sensor is based on a Sagnac interferometer and uses light beams counterrotating in one or more oblong circular shaped coils of optical fiber in which dual phase modulators are used to generate an AC signal to enable detection of a rotation rate output. The sensor also includes means to mechanically or electrically flip to sensitive axis of the rotation sensor to null out bias drift. If one coil is used, the flipping is in 90.degree. segments. When two coils at 90.degree. to each other are used, they are flipped 180.degree..