Optical rate sensor having modulated clockwise and counterclockwise beams
US5650849A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 17, 1994 |
| Grant date | Jul 22, 1997 |
| Priority date | — |
| Expiry date | Oct 17, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C19/72
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an open loop rate sensor clockwise (CW) and counterclockwise (CCW) beams from a common source 10 pass in opposite directions around a coil 20 of optical fiber and recombine on a detector 24. A phase modulator 22 applies a stepped phase modulation in which each step is of duration equal to the transit time of the coil 20 and in which alternate steps are zero. The intermediate steps increase linearly from zero to 2.pi.. Without modulation, the CW and CCW beams combine on the detector with a combined intensity which varies as a cosine of rate. The above modulation causes two points to either side of the cosine fringe to be sampled which move progressively farther as the amplitude of the stepped modulation increases. The sample data is processed to determine the rate applied to the rate sensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.