Fiber optic measuring device, rate gyro, navigation and stabilization system, and current sensor
US5181078A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 1991 |
| Grant date | Jan 19, 1993 |
| Priority date | — |
| Expiry date | Apr 16, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C19/726
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A fiber optic measuring device can be used, for example, as a rate gyro. Variation in a measured parameters engenders a phase difference between two waves. The measuring device includes a light source 1, a SAGNAC ring interferometer 2, a detector 3, a phase modulator 4, and a electronic unit 7. The electronic unit 7 includes a processing system 9 which furnishes a signal that is a function of the measured parameter and an electronic sub-unit 12 for controlling the phase modulator 4. The control signal for the modulator is a superposition of a first, periodic gating, bias signal .PHI..sub.b (t) with period 2.tau. and amplitude .PHI..sub.bm, and of a second, staircase, negative-feedback signal .PHI..sub.m (t) synchronized with .PHI..sub.b (t), each step of which has a duration equal to .tau. or to one of its sub-multiples, and an amplitude .PHI..sub.s, which is a function of the value of the measured parameter and which falls back to zero when its amplitude exceeds a predetermined value .PHI..sub.mm . .PHI..sub.bm and .PHI..sub.mm are slaved to 2.PHI..sub.bm +.PHI..sub.mm =2n.pi. (where n is an integer). The response to the singular phase shift introduced during the fall-back of the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.