Phase-Nulling Fiber Optic Gyro Development Review

E. Udd, R. F. CahillMcDonnell Douglas Astronautics CompanyHuntington Beach, California 92647AbstractProgress in developing a fiber -optic gyro based on active closed loop phase compensationis described. Comparisons are made between a breadboard proof -of- principle unit built in1978, a 12.7 -cm- diameter, 2.5 -cm thick unit built in 1979, and a 6.5 -cm- diameter, 1.7 -cmthick unit built in 1980.IntroductionFiber -optic gyros have the potential to be low -cost, solid -state replacements for mechan-ical gyros. In order to be compatible with advanced navigation systems, the capacity forwide dynamic range and linear digital output is highly desirable. The Phase -Nulling OpticalGyro (PNOG) achieves these goals by offsetting the phase difference induced by rotation be-tween counterpropagating beams in a fiber -optic coil by a phase difference generated by afrequency shift impressed upon one of the counterpropagating beams while it propagates inthe fiber coil. This paper reviews the fundamental principles underlying the operation ofthe PNOG as well as the performance of succeeding generations of breadboard and brassboard