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:
Sep. 03, 2002
Filed:
May. 23, 2000
John R. Hall, Woodland Hills, CA (US);
Daniel A. Tazartes, West Hills, CA (US);
Northrop Grumman Corporation, Woodland Hills, CA (US);
Abstract
A phase and intensity modulated IFOG has a light source responsive to an intensity modulation signal for providing an intensity modulated light signal. A Sagnac interferometer has a fiber optic coil. The coil receives and circulates a clockwise and counter-clockwise beams. The Sagnac interferometer is responsive to an intensity modulated light signal at a first input port, and to a phase modulation signal at a phase modulation input terminal for outputting a non-reciprocal interference signal. A PSD detector system responds to the non-reciprocal interference signal and provides a demodulated bias signal. An intensity signal generator has an output that provides the intensity modulation signal. A phase signal generator provides the phase modulation signal to the phase modulation input terminal. The intensity signal generator and the phase signal generator have a common frequency. The phase difference &thgr; between the phase modulation signal and the intensity modulation signal is adjustable in response to at least a first control signal. A computer with a digitizing sampler is coupled to receive and digitize successive sample values of the demodulated bias signal. The computer executes a program that adjusts the phase difference &thgr; between the intensity modulation signal and the phase modulation signal to drive the amplitude of the sample values of the demodulated bias signals to a minimum. The computer program successively calculates and outputs an estimate of the input rotation rate about the Sagnac sensitive axis as a function of the phase angle &thgr;.