Method and apparatus for overcoming cross-coupling in a fiber optic gyroscope employing overmodulation
US5682241A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1996 |
| Grant date | Oct 28, 1997 |
| Priority date | — |
| Expiry date | Mar 11, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C19/72
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A phase modulator applies sequences of artificial phase shifts in the region of overmodulation between light beams counterpropagating within the sensor coil of a Sagnac interferometer to obtain improved random walk performance. The sequences are composed of phase shifts of .+-.a.pi./2b and .+-.(4b-a).pi./2b where a is an odd integer and b is an integer greater than 1. The waveform for driving the phase modulator is derived from a 2.pi. radian mapping plotted so that adjacent driving signal values differ by a.pi./2b or -(4b-a).pi./2b in a first angular direction and by -a.pi./2b or by (4b-a).pi./2b in the opposite angular direction. Angular transitions about the mapping may be predetermined to generate a deterministic, random, or pseudo-random modulation sequence. In the event that a deterministic sequence is chosen, it is examined for orthogonality properties to assume zero average output bias from crosstalk.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.