WO1992004597A1 - Appareil de mesure de la vitesse angulaire par interference optique - Google Patents
Appareil de mesure de la vitesse angulaire par interference optique Download PDFInfo
- Publication number
- WO1992004597A1 WO1992004597A1 PCT/JP1991/001149 JP9101149W WO9204597A1 WO 1992004597 A1 WO1992004597 A1 WO 1992004597A1 JP 9101149 W JP9101149 W JP 9101149W WO 9204597 A1 WO9204597 A1 WO 9204597A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- light
- optical
- phase
- phase modulating
- modulating means
- Prior art date
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/58—Turn-sensitive devices without moving masses
- G01C19/64—Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams
- G01C19/72—Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/58—Turn-sensitive devices without moving masses
- G01C19/64—Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams
- G01C19/72—Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
- G01C19/726—Phase nulling gyrometers, i.e. compensating the Sagnac phase shift in a closed loop system
Definitions
- the light from the light source is divided into two and supplied to both ends of the loop-shaped optical transmission line as right-handed light and left-handed light, respectively.
- a phase shift is given to the incident light and the light emitted from the optical transmission path by a modulation signal, and the two lights emitted from the loop-shaped optical transmission path are combined and interfered, and the interference light is converted into an electric signal.
- the present invention relates to an optical interference gyro which detects an angular velocity applied to a loop-shaped transmission path around its axis by synchronously detecting the electric signal with a modulation signal of a phase modulator.
- Fig. 1 shows a conventional optical tachometer.
- the light emitted from the light source 11 is split into two in an optical splitter 12, one of which passes through a polarizer 13, is guided to an optical splitter 14, and is split into two in an optical splitter 12.
- the other is terminated by a terminating element 20.
- the light guided to the optical splitter 14 is split into right-handed light and left-handed light, and the right-handed light undergoes phase modulation by the phase modulator 15 immediately after exiting the optical splitter 14. After that, the light is incident on one end of an optical fiber coil 16 as a loop optical transmission line, propagates clockwise through the optical fiber coil 16, and then reaches the optical branching device 14 again.
- the counterclockwise light exits the optical splitter 14 and enters the other end of the optical fiber coil 16, propagates counterclockwise through the optical fiber coil 16, and after being phase-modulated by the phase modulator 15. Immediately after receiving, it reaches the optical splitter 14 again.
- the clockwise light and the counterclockwise light that have propagated through the optical fiber coil 16 meet and interfere with each other.
- the right-handed light and the left-handed light are subjected to a periodic phase shift by the phase modulator 15.Therefore, there is a periodic phase difference between the right-handed light and the left-handed light. Occurs.
- the frequency f m of the modulation signal driving the phase modulator 15 is 1 (2 ⁇ ) (where r is the time for light to propagate through the optical fiber coil 16)
- the right-handed light undergoes a phase shift cw by the phase modulator 15, passes through the optical fiber coil 16, and passes through the optical splitter 14.
- the phase shift ccw that the left-handed light receives at the phase modulator 15 is as shown in Fig. 2A. Since the time elapses by r with respect to the modulated signal, the phase becomes opposite to the phase shift ⁇ cw as shown in FIG. 2B.
- the phase difference CW — ccw between the clockwise light and the counterclockwise light synthesized by the optical branching device 14 changes in two cycles as shown by a curve 17 in FIG. Therefore, the interference light obtained by combining these two lights repeatedly strengthens and weakens each other with a period ⁇ , that is, light whose intensity changes periodically.
- the intensity of the interference light in response to both the phase difference of the light ⁇ 5 cw _ ccw is changed as shown by curve 1 8, hence the intensity change is repeated in a cycle manually as curve 1 9.
- the dry light from the optical splitter 14 reaches the optical splitter 12 through the polarizer 13 and is split into two lights, one of which is converted into an electric signal by the photodetector 21.
- This electric signal is a signal that changes at twice the frequency of the phase modulation frequency f m , as shown by the curve 19 in FIG. 2, that is, 1 Z ⁇ in the example of FIG.
- phase difference occurs between the clockwise and counterclockwise lights due to the sanitary effect according to the input angular velocity. . For this reason, a phase difference based on the input angular velocity is superimposed on the curve 17 in FIG.
- the good urchin phase difference is superimposed on a direct current, in accordance with the DC phase difference in the output electrical signal of the photodetector 2 1, it appears component of phase modulation frequency f m.
- the output of the photodetector 2 1 is the synchronous detection by the reference signal of the phase modulation frequency f m and the same frequency in the synchronous detection circuit 2 2.
- the output of the photodetector 21 is only an even-numbered component of the phase modulation frequency, and mainly only the doubled component, so the output of the synchronous detection circuit 22 is zero.
- the photodetector 2 1 Output occurs components of the phase modulation frequency f n and the same frequency, the output of the polarity and level corresponding to the direction and magnitude of the input angular velocity is obtained from the synchronous detection circuit 2 2, which is supplied to the output terminal 2 3
- the input angular velocity can be detected.
- the phase modulation signal supplied to the phase modulator 15 and the reference signal supplied to the synchronous detection circuit 22 are generated by a modulation signal generator 24.
- phase modulator 15 When light passes through the phase modulator 15, the light undergoes not only a phase shift in the modulated signal but also intensity modulation. 'This is because phase modulation is performed by changing the refractive index of the medium through which light propagates.When the refractive index of the medium changes, the confinement state of the light in that medium changes, so the medium is synchronized with the phase modulation signal. The light confinement state changes, and the intensity of the light passing therethrough is modulated.
- both the clockwise light and the counterclockwise light passing through the phase modulator 15 are subjected to intensity modulation at the frequency f m , and the clockwise light and the counterclockwise light subjected to the intensity modulation are separated by the optical splitter 1.
- the input angular rate is detected component of the frequency f m from the synchronous detection circuit 2 2 in the state of zero port, which is the offsets-error bi ⁇ scan values of the optical interference ⁇ speedometer. If this offset offset is large, the zero point will fluctuate at a fixed rate if any factor changes due to disturbance or the like, and the zero point stability will be poor.
- the interference light is subjected to intensity modulation at a frequency twice as high as the modulation signal frequency fn, and this interference light is split by the optical splitter 12 and one is supplied to the photodetector 21. And the other returns to light source 1 1.
- the returned interference light is detected by a photodiode for controlling the light intensity of the light emitted from the light source 11, and the automatic light intensity stabilizing circuit reduces the light intensity of the light source 11 by stopping this detection output.
- intensity modulation is applied to the light emitted from the light source 11 at twice the frequency of the modulation signal frequency ⁇ m .
- the optical splitter 1 4 also exist intensity modulation of f m component synthesized interference light, synchronization input angular velocity in the same manner as described above even zero detection circuit 2 2
- the output is generated from the output, and the bias value is offset.
- An object of the present invention is to improve bias zero stability even when intensity modulation by a phase modulator is present or when light from a light source is subjected to intensity modulation, without causing an error in a bias value. It is to provide an optical interference gyro which can be used.
- the splitting ratio of the optical splitter 12 for splitting the light emitted from the light source 11 was set to 1 to 1, the loss of the optical element was set to zero, and the light from the light source 11 was incident. Assuming that the light quantity is 100, the light quantity of the light split into the polarizer 13 and the terminating element 20 becomes 50, and this 50 light quantity returns from the optical fiber coil 16 to the light source 11 The amount of returning light and the amount of signal light to the photodetector 21 are all 25 times, and the signal-to-noise ratio of the optical system can be increased, but the amount of returning light to the light source 11 also becomes the maximum. This has the disadvantage that the performance of the optical interference gyro deteriorates.
- the light source 11 used in the optical interference gyro often uses an optical resonator like a semiconductor laser.
- a semiconductor laser forms an optical resonator using cleavage planes at both ends of a laser chip as a reflecting mirror, and extracts light resonated by the resonator as laser light.
- reflected light from a portion other than the cleavage surface of the semiconductor laser chip is used.
- this reflected light or return light By being incident on one chip, another resonator is formed in addition to the resonator that constitutes the semiconductor laser.
- This other resonator is called an external resonator because it is configured outside the semiconductor laser.
- the spectrum shape, center wavelength, coherence, etc. of the light source fluctuate. It has been reported that such phenomena are also caused in the superluminescent diode (SLD), which is often used in optical gyros.
- SLD superluminescent diode
- Another object of the present invention is to reduce the scale factor fluctuation and the amount of return light to the light source which causes fluctuation of coherence, which reduces the scale factor fluctuation and the amount of bias error. To provide an improved light interference angular velocity.
- the first phase modulator is inserted in series between the optical branching means and one end of the loop-shaped optical transmission line, and the second phase modulator is connected in series with the first phase modulator. Insert the container.
- the characteristics of the second phase modulator are preferably the same as those of the first phase modulator, and a modulation signal of the same frequency and the same frequency as the modulation signal for the first phase modulator is transmitted to the second phase modulator.
- the light that has passed through the loop-shaped optical transmission path is received by the second phase modulator so that the light traveling around the same direction receives the phase shift received by the first phase modulator and the phase shift of the same direction received by the second phase modulator.
- the phase of the modulation signal to be supplied to the second phase modulator is selected. That is, the modulation supplied to the first phase modulator When the signal (2 f m t), a modulation signal supplied by the second phase modulator - and (2 ⁇ f m t 2 ⁇ ⁇ ⁇ ⁇ ).
- the period ⁇ (2 ⁇ ⁇ m t) sine wave, such as a rectangular wave is used.
- the clockwise light and the counterclockwise light are respectively subjected to an added phase shift in the first and second phase modulators, and the same operation and effect as the conventional phase modulation can be obtained.
- Each intensity modulation in the optical modulator is obtained by multiplying one of the intensity modulations by the other intensity modulation, that is, acts as frequency mixing. Therefore, during the intensity modulation of the light passing through the loop optical transmission line, The component of the phase modulation frequency f m is not blocked.
- the optical splitter that splits the returned light from the loop-shaped optical transmission path into the light detector and the light source is split into the light detector from the light amount split into the light source.
- the branching ratio is selected so that the amount of light to be emitted is large. That is, the branching ratio of this optical branching device is shifted from 1: 1.
- the light amount on the light source side: the light amount on the photodetector side is, for example, 5:95 to 40:60, preferably 20:80 to 30: Selected to be around 70.
- the light from the light source is more branched to the terminating element side than the loop-shaped optical transmission line side, the amount of light on the loop-shaped optical transmission line side is reduced, and the signal-to-noise of the optical system is reduced. Since the ratio becomes small, the light amount of the light source is made larger than before so that the signal-to-noise ratio becomes a required value or more as necessary. On the other hand, the amount of light returning to the light source such as signal light (driving light) propagating through the loop-shaped optical transmission line, Rayleigh scattered light from each point in the optical fiber, and reflected light from the fiber fusion point is measured.
- FIG. 1 is a block diagram showing a conventional optical interferometer
- Fig. 2 is the phase shift of right-handed and left-handed light, the phase difference between these two lights, and the interference light between the two lights.
- FIG. 3 shows a change in light intensity
- FIG. 3 is a block diagram showing an embodiment in which the present invention is applied to an open-loop type optical interference gyro
- FIGS. Block diagram showing an embodiment applied to an optical interference gyro with a system
- Fig. 7 shows an example in which the phase modulators 15, 26, 28, 31 in Fig. 6 are integrated.
- FIG. 8 is a perspective view showing another embodiment in which the present invention is applied to an open-loop optical tachometer.
- FIG. 3 shows an embodiment of the present invention, in which parts corresponding to those in FIG. 1 are denoted by the same reference numerals.
- the light from the light source 11 has a branching ratio.
- the light that enters the 1: 4 optical branching device 25 and is split by the optical branching device 25 into two light beams having a smaller amount of light is polarized.
- the light is incident on the element 13 side, and the larger one is incident on the termination element 20.
- the dry light returned from the optical fiber coil 17 enters the optical splitter 25 and is split into the light source 11 side and the photodetector 21 side.
- a phase modulator 15 is further inserted in series between the optical splitter 14 and one end of the optical fiber coil 16, and the optical splitter 14 and the optical fiber coil 16 are connected to each other.
- a phase modulator 26 is inserted in series with the other end. In this case, the phase modulator 26 is connected in series to the phase modulator 15 via the optical fiber coil 16.
- the phase modulator 26 has the same characteristics as the phase modulator 15, and the clockwise rotation of the right-handed light has the same phase shift as the phase shift received by the phase modulator 15.
- the phase modulator 26 is driven by a modulation signal having the same periodic function and the same frequency as the modulation signal for the phase modulator 15 and having a phase delayed by 2 ⁇ .
- This modulation signal is also generated by the modulation signal generator 24.
- the modulation signal for the phase modulator 15 is (2 ⁇ f n t), and as shown in FIG. Assuming that 1 / (2), the modulation signal to the phase modulator 26 is ⁇ (2
- clockwise light undergoes an additional phase shift in phase modulators 15 and 26, and left-handed light also undergoes an additional phase shift in phase modulators 15 and 26.
- a clockwise light and Hidarigari light synthesized by the optical splitter 1 4 there is a phase difference that varies a periodic function (2 ⁇ ⁇ m t). Therefore, the interference light obtained by combining these two lights is converted into an electric signal by the photodetector 21 and the electric signal is synchronously detected to detect the angular velocity input to the optical fiber coil i 6 in the same manner as before. be able to.
- the frequency component of the intensity modulation of the counterclockwise light passing through the phase modulator 15 has no fm component.
- the amount of return light to the light source 11 is 4 and the amount of signal light to the photodetector 21 is 16 Becomes In this way, the amount of light returning to the light source 11 becomes considerably smaller than before, and the spectrum shape, center wavelength, and dryness of the light source 11 are less likely to fluctuate, and the optical fiber In addition, the fluctuations in the sour factor and bias at least are also reduced.
- the present invention is applied to an open-loop optical interference gyro, but can also be applied to a closed-loop optical interference gyro.
- An example of this is shown in FIG. 4 with the same reference numerals assigned to parts corresponding to FIG. 3, that is, the output of the synchronous detection circuit 22 is supplied to the sawtooth wave generation circuit 27, and the sawtooth wave generation circuit 27 Generates a sawtooth wave signal (sometimes a staircase sawtooth wave) at an inclination direction according to the polarity of the input and at an inclination angle according to the magnitude of the input.
- a sawtooth wave signal sometimes a staircase sawtooth wave
- the phase modulation 28 may be omitted, and the feedback saw-tooth wave signal from the saw-tooth wave generation circuit 27 may be added to the phase modulator 26 as shown in FIG. Alternatively, this feedback sawtooth signal may be applied to the phase modulator 15.
- an additional phase modulator 31 is inserted between the optical branching device 14 and one end of the optical fiber coil 16.
- the phase modulator 31 may be driven by the saw-tooth wave signal R that drives the phase modulator 28 and the sawtooth signal R having the opposite polarity. In the configurations shown in FIGS.
- the peak value of the feedback sawtooth signal is a voltage value required to cause a phase shift of 2 ⁇ radian in the light, but in the configuration shown in FIG.
- the peak value of the wave signal need only be a voltage required to cause a phase shift of ⁇ radian in the light, and a low voltage is sufficient, and the design of the sawtooth wave generation circuit 27 becomes easy.
- phase modulators 15, 26, 28, 31 can be integrated on one substrate. That is, as shown in FIG. 7, an optical waveguide 33 is formed in an L-shape on an electro-optic crystal substrate 32 such as lithium niobate to form an optical splitter 14, and one of the split optical waveguides is formed.
- a phase modulator 15 is formed by forming the electrodes 34 and 35 with the waveguide interposed therebetween, and a phase modulator 31 is formed by forming the electrodes 36 and 37 with the branch optical waveguide interposed therebetween.
- phase modulators 26 and 28 are formed by forming two pairs of electrodes with the other branch optical waveguide interposed therebetween.
- the phase modulators 28 and 31 may be omitted, and the feedback sawtooth signal, 1 "may be supplied to the phase modulators 15 and 26, respectively.
- phase modulator 26 is connected in series with the phase modulator 15 via the optical fiber coil 16, but the phase modulator 26 may be directly connected in series with the phase modulator 15 .
- the same reference numerals are given to the portions corresponding to FIG. 3 in FIG. 8, and the description is omitted.
- the optical branching device 25 As the optical branching device 25, a so-called bulk type using a prism, an optical fiber power braider in which two optical fiber clads are polished and joined to each other and bonded to each other, 2 Optical fiber power brass obtained by fusing and extending this optical fiber, an optical directional coupler composed of an optical waveguide, a double ⁇ -shaped branch composed of an optical waveguide, and the like can be used. 3 to 6, and 8, the 1: 1 optical splitter 12 shown in FIG. 1 may be used instead of the optical splitter 25. 3 to 6 and 8, the phase modulator 26 may be omitted. As described above, according to the present invention, the optical splitter and one end of the loop-shaped optical transmission line are connected to each other.
- the bias value is based on the light intensity modulation generated by the phase modulator.
- the offset error of the light source can be reduced to zero, and similarly, when the light from the light source is intensity-modulated, the offset error of the bias value does not occur based on this. Therefore, the light emission amount of the light source can be increased, and the S / N can be increased. As a result, a highly stable optical tachometer with a small bias value offset can be obtained.
- the light from the light source is branched to the loop-shaped optical transmission line side, and the interference light of the left and right-handed light returning from the loop-shaped optical transmission line is branched to the photodetector side and the light source side.
- the splitting ratio is selected so that the amount of interfering light split off from the light source side to the photodetector side is small, so the amount of return light to the light source is small and the light source Fluctuations in the light source characteristics such as the ram shape, center wavelength, and coherence are smaller than before, and as a result, the scale factor fluctuation and bias error of the optical interference gyro are reduced.
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Optics & Photonics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
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Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP91915269A EP0502196B1 (en) | 1990-08-31 | 1991-08-29 | Optical interference angular velocity meter |
DE69115877T DE69115877T2 (de) | 1990-08-31 | 1991-08-29 | Gerät zum messen der winkelgeschwindigkeit durch optische interferenz |
US07/848,967 US5327214A (en) | 1990-08-31 | 1991-08-29 | Optical interferometric gyro having reduced return light to the light source |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP23082290A JPH04110718A (ja) | 1990-08-31 | 1990-08-31 | 光干渉角速度計 |
JP2/230822 | 1990-08-31 | ||
JP2324013A JP2548044B2 (ja) | 1990-11-27 | 1990-11-27 | 光干渉角速度計 |
JP2/324013 | 1990-11-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1992004597A1 true WO1992004597A1 (fr) | 1992-03-19 |
Family
ID=26529557
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1991/001149 WO1992004597A1 (fr) | 1990-08-31 | 1991-08-29 | Appareil de mesure de la vitesse angulaire par interference optique |
Country Status (5)
Country | Link |
---|---|
US (1) | US5327214A (ja) |
EP (1) | EP0502196B1 (ja) |
CA (1) | CA2071882C (ja) |
DE (1) | DE69115877T2 (ja) |
WO (1) | WO1992004597A1 (ja) |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5459600A (en) * | 1994-03-08 | 1995-10-17 | Optimux Systems Corporation | Optical telecommunications system employing multiple phase-compensated optical signals |
US5493623A (en) * | 1994-06-28 | 1996-02-20 | Honeywell Inc. | PZT fiber optic modulator having a robust mounting and method of making same |
US5598489A (en) * | 1994-07-27 | 1997-01-28 | Litton Systems, Inc. | Depolarized fiber optic rotation sensor with low faraday effect drift |
US8446589B2 (en) * | 2009-03-06 | 2013-05-21 | Honeywell International Inc. | Residual intensity modulation (RIM) control loop in a resonator fiber-optic gyroscope (RFOG) |
US8294900B2 (en) | 2009-04-01 | 2012-10-23 | Honeywell International Inc. | Systems and methods for resonator fiber optic gyroscope intensity modulation control |
WO2012048448A1 (zh) * | 2010-10-15 | 2012-04-19 | 北京大学 | 干涉型全光纤陀螺仪的零点漂移抑制方法以及相应的干涉型全光纤陀螺仪 |
RU2497077C1 (ru) * | 2012-05-03 | 2013-10-27 | Федеральное государственное унитарное предприятие "Научно-производственный центр автоматики и приборостроения имени академика Н.А. Пилюгина" (ФГУП "НПЦАП") | Волоконно-оптический измеритель угловой скорости |
US20150022818A1 (en) * | 2012-06-08 | 2015-01-22 | The Board Of Trustees Of The Leland Stanford Junior University | Laser-driven optical gyroscope with push-pull modulation |
US9207082B2 (en) * | 2012-08-15 | 2015-12-08 | Honeywell International Inc. | Fiber resonator gyroscope with low round trip loss and high output power |
US9008221B2 (en) | 2013-04-01 | 2015-04-14 | Honeywell International Inc. | Spurious frequency attenuation servo |
EP3516333B1 (en) | 2016-09-20 | 2023-05-03 | The Board of Trustees of the Leland Stanford Junior University | Optical system and method utilizing a laser-driven light source with white noise modulation |
US11566900B2 (en) * | 2019-03-06 | 2023-01-31 | Purdue Research Foundation | MEMS rotation rate sensor |
US11231278B1 (en) | 2020-10-15 | 2022-01-25 | The Board Of Trustees Of The Leland Stanford Junior University | System and method for generating broadband spectrum by phase modulation of multiple wavelengths |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59195220A (ja) * | 1983-04-20 | 1984-11-06 | Masayuki Izutsu | 光学的検出装置 |
JPS62239011A (ja) * | 1986-04-11 | 1987-10-19 | Agency Of Ind Science & Technol | 光フアイバジヤイロ |
JPH02262006A (ja) * | 1989-03-20 | 1990-10-24 | British Aerospace Plc <Baf> | 光フアイバジヤイロスコープ |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3123163A1 (de) * | 1981-06-10 | 1983-01-05 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | "verfahren und anordnung zur messung absoluter drehungen" |
GB2100855B (en) * | 1981-06-18 | 1984-10-10 | Standard Telephones Cables Ltd | Sideband modulating/demodulating fibre optic gyroscope |
DE3533695A1 (de) * | 1985-09-21 | 1987-03-26 | Teldix Gmbh | Verfahren zur messung der drehgeschwindigkeit |
US4712306A (en) * | 1985-12-27 | 1987-12-15 | Mcdonnell Douglas Corporation | Fiber optic earth rotation gyro compass |
GB2216652B (en) * | 1988-03-09 | 1992-09-02 | British Aerospace | Apparatus and method for determining the wavelength of optical radiation and optical apparatus employing said apparatus and method |
US5018860A (en) * | 1989-01-26 | 1991-05-28 | Honeywell Inc. | Fiber optic gyroscope balanced plural serrodyne generators combined signal phase difference control |
US5018859A (en) * | 1989-01-26 | 1991-05-28 | Honeywell Inc. | Fiber optic gyroscope balanced plural serrodyne modulators phase difference control |
-
1991
- 1991-08-29 US US07/848,967 patent/US5327214A/en not_active Expired - Fee Related
- 1991-08-29 DE DE69115877T patent/DE69115877T2/de not_active Expired - Fee Related
- 1991-08-29 WO PCT/JP1991/001149 patent/WO1992004597A1/ja active IP Right Grant
- 1991-08-29 CA CA002071882A patent/CA2071882C/en not_active Expired - Fee Related
- 1991-08-29 EP EP91915269A patent/EP0502196B1/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59195220A (ja) * | 1983-04-20 | 1984-11-06 | Masayuki Izutsu | 光学的検出装置 |
JPS62239011A (ja) * | 1986-04-11 | 1987-10-19 | Agency Of Ind Science & Technol | 光フアイバジヤイロ |
JPH02262006A (ja) * | 1989-03-20 | 1990-10-24 | British Aerospace Plc <Baf> | 光フアイバジヤイロスコープ |
Non-Patent Citations (1)
Title |
---|
See also references of EP0502196A4 * |
Also Published As
Publication number | Publication date |
---|---|
DE69115877T2 (de) | 1996-09-05 |
EP0502196B1 (en) | 1995-12-27 |
CA2071882A1 (en) | 1992-03-01 |
CA2071882C (en) | 1996-02-13 |
EP0502196A1 (en) | 1992-09-09 |
EP0502196A4 (en) | 1993-05-05 |
DE69115877D1 (de) | 1996-02-08 |
US5327214A (en) | 1994-07-05 |
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