# US 11,079,231 B2 · Optical phase modulating scheme of a MIOC of an interferometer type fiber optic gyroscope

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- Number: US 11,079,231 B2
- Document ID: US11079231B2
- Status: Granted
- Kind: B2
- Application number: 16/632,491
- Filed: 2018-07-24
- Published: 2021-06-03
- Granted: 2021-08-03
- Earliest claimed: 2017-08-07
- Applicants: Civitanavi Systems S.R.L.
- Inventors: Enrico Quatraro; Andrea Pizzarulli
- Web page: https://patentgrep.com/patent/US11079231B2

## CPC

- G01C 19/723: {Heterodyning fibre optic gyrometers}
- G01C 19/72: with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)

## Abstract

An optical phase modulating method of a multi-integrated optical circuit of an interferometric fiberoptic gyroscope with a control feedback control with a digital modulation and demodulations approach includes the step of modulating at eight modulation levels. Each modulation levels has a duration of one-quarter of a light propagation time in a fiberoptic coil.

## Claims

### Claim 1

An optical phase modulating method of a multi-integrated optical circuit (MIOC) of an interferometric fiberoptic gyroscope (I-FOG) with a control loop feedback control with a digital modulation and demodulation approach, the optical phase modulating method comprising:
modulating at eight modulation levels wherein each modulating level has a duration of one-quarter of a light propagation time τ in a fiberoptic coil.

### Claim 2 (depends on 1)

The optical phase modulating method of claim 1, further comprising:
correcting a ΔΦR phase shift produced by a Sagnac effect in a sensor of the interferometric fiberoptic gyroscope after an εR error measure with a period equal to the light propagation time τ.

### Claim 3 (depends on 1)

The optical phase of claim 1, further comprising:
correcting the MIOC modulation channel gain in a sensor of the I-FOG after an εG error measure equal to the light propagation time τ.

### Claim 4 (depends on 1)

The optical phase of claim 1, wherein a control frequency of the fiberoptic coil of a given length is increased by a factor of two as a consequence of the modulation level being one-quarter of the light propagation time τ.