WO1999056080A1 - Gyroscope a fibres optiques - Google Patents

Gyroscope a fibres optiques Download PDF

Info

Publication number
WO1999056080A1
WO1999056080A1 PCT/JP1999/002163 JP9902163W WO9956080A1 WO 1999056080 A1 WO1999056080 A1 WO 1999056080A1 JP 9902163 W JP9902163 W JP 9902163W WO 9956080 A1 WO9956080 A1 WO 9956080A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
modulation
optical fiber
phase
constant output
Prior art date
Application number
PCT/JP1999/002163
Other languages
English (en)
Japanese (ja)
Inventor
Yoshiyuki Okada
Yoshiaki Imamura
Mikio Morohoshi
Kanshi Yamamoto
Original Assignee
Tokimec Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP11711498A external-priority patent/JPH11304498A/ja
Application filed by Tokimec Inc. filed Critical Tokimec Inc.
Publication of WO1999056080A1 publication Critical patent/WO1999056080A1/fr

Links

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
    • G01C19/726—Phase nulling gyrometers, i.e. compensating the Sagnac phase shift in a closed loop system

Definitions

  • the present invention relates to an optical fiber gyro applied to, for example, an aircraft, a ship, an automobile, and the like, which detects a rotational angular velocity or a rotational angle, and in particular, cancels a sannyak phase shift by a stepped serodyne signal.
  • the present invention relates to a digital optical fiber gyro configured in a closed loop.
  • the light intensity change of the interference light obtained by recombining the two lights propagating in the optical fiber loop in the opposite directions is represented by d) S, the phase difference between the two lights. Then cos ((
  • a phase modulator that modulates the phase of two lights propagating through an optical fiber loop
  • the phase modulator has a phase shift of + ⁇ / 2 and - ⁇ / 2 as shown in Fig. 23.
  • T propagation time of light in an optical fiber loop
  • the light intensity change due to the saniac phase difference of the interference light is calculated by (PQ / 2 ) 'C 0 S ((/) S ⁇ ⁇ / 2) (where ⁇ is the peak value of the light intensity of the interference light) I'm trying.
  • the serodin signal which is a staircase signal whose duration is normally a staircase signal
  • the phase modulator performs phase modulation so as to generate a phase difference having the same amount and a different sign as that of the Sanyak phase difference corresponding to the input angular velocity to the optical fiber gyro.
  • a closed loop is configured to cancel the Sagnac phase difference between two lights propagating in the optical fiber loop.
  • the output of the serodyne signal cannot be increased indefinitely, it is normally reset when the phase shift due to the serodyne signal reaches ⁇ 2 ⁇ .
  • Digital optical fiber jar openings that solve this problem include those described in U.S. Pat. No. 5,141,316 and U.S. Pat. No. 4,948,252.
  • the former is a phase modulation signal input to the phase modulator.
  • the cycle of each step of the phase modulation signal is, for example, / 2 (2 in total).
  • A is 2.
  • the modulation phase difference is as shown in Fig. 24.
  • the latter uses a signal obtained by calculating a gain signal obtained from a phase difference electric signal and a total phase modulation signal as a phase modulation signal to be input to the phase modulator.
  • This total phase modulation signal is obtained by summing the following signals.
  • a velocity bias signal consisting of a periodic square wave with a first frequency.
  • a gain-bias signal consisting of a series of step voltages that transition at the end of a series of equally spaced periods equal to half the period of the serodin signal.
  • a continuous equal interval time is / j (j is an integer). If j is 2, the velocity bias signal will be at half the frequency. Also, the velocity bias signal is a square wave that transitions between ⁇ / 2 and - ⁇ / 2, and the gain bias signal has a series of induced phase shifts of 2 ⁇ , 0, -2 ⁇ , 0. . In this case, the modulation phase difference is, for example,
  • the gyro output generated by the serodin signal can be controlled.
  • the scale factor error can be reduced. Disclosure of the invention
  • the light intensity value of the detected interference light changes, and a stable cellodies Control and modulation control.
  • the change in the light intensity value of the above-mentioned sensation light causes the Sanyak phase difference ( ⁇ . / 2) 'cos ( ⁇ s ⁇ 7t / 2) (where P is the interference).
  • the detection gain of the peak light intensity of the light, ⁇ / 2 is the phase modulation amplitude value, changes, and the loop gain of serodin control changes.
  • the random walk value is a value indicating an S / N ratio of a light intensity signal of the interference light, and is defined by an execution value of a random noise component included in the signal.
  • this random walk value is a function in which the light intensity value of the interference light is a parameter, and if this light intensity value changes, the phase modulation amplitude for minimizing the random walk value also changes.
  • the two types of light propagating in the optical fiber loop in opposite directions are generated. No consideration is given to a change in the light intensity value of the interference light due to a change in the output characteristics of the light source used or other influences, and the phase modulation signal is generated so as to have a predetermined phase modulation amplitude. Therefore, if the light intensity value of the interference light changes, the random walk value cannot be sufficiently reduced.
  • the output wave passes through the peak point (brightest point) or bottom point (bottom point) of the light beam.
  • a spike-like noise occurs in the shape. If the detection light includes an error due to optical spikes, an error occurs in the modulation control, and the modulation gain of the phase modulation signal and the serodin signal cannot be optimized.As a result, the optical gyro A scale factor error at the output may occur.
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a high-precision digital optical fiber gyro capable of performing stable operation.
  • an object is to enable stable modulation control and cellodyne control by enabling detection of a modulation gain error and a change in light intensity of interference light.
  • the present invention provides a rotation angular velocity or rotation angle according to a saniac phase difference of interference light obtained by recombining two lights propagating in an optical fiber loop in directions opposite to each other.
  • Optical fiber mouth that detects
  • a light receiving unit that detects the light intensity of the interference light and converts the light intensity into an electric signal; and, based on a signal corresponding to the light intensity of the interference light detected by the light receiving unit, determines a sanyak phase difference of the interference light.
  • a signal phase calculating means for calculating a signal;
  • the saniae of the interference light generated by the saniae phase difference calculating means A cellodine signal generating means for generating a cellodine signal composed of a step-like wave for canceling the Saniyak phase difference of the interference light, according to a signal corresponding to the phase difference of the interference light;
  • the phase difference of the light is ⁇ ( ⁇ 0), soil ( ⁇ + 0 + and ⁇ ( ⁇ + 0 ⁇ (5)), or soil ( ⁇ + 0), ⁇ ( ⁇ and + ⁇ ) by synthesizing a bias modulation signal for performing phase modulation so as to repeat the six values in a predetermined time interval and in a predetermined order, and a serodin signal generated by the serodin signal generation means.
  • Synthetic signal generating means for generating a composite signal of various phase modulations
  • a phase modulator that phase-modulates each of the two lights according to the composite signal of various phase modulations generated by the composite signal generation unit
  • Modulation gain calculation for calculating a signal corresponding to a modulation gain error generated at the time of phase shift by the bias modulation signal based on a signal corresponding to the light intensity of the interference light detected by the light receiving unit.
  • Modulation gain control means for controlling the gain of the composite signal of the various phase modulations according to a signal corresponding to the modulation gain error generated by the modulation gain calculation means.
  • the synthesized signal generating means includes:
  • First constant output signal generation means for generating a first constant output signal having an output value necessary to perform the phase shift of ⁇
  • second constant output signal generating means for generating a second constant output signal having an output value necessary for performing the phase shift of ⁇
  • Third constant output signal generating means for generating a third constant output signal having an output value necessary for performing a phase shift of the
  • First adding means for adding the bias modulated signal generated by the bias modulated signal generating means and the serodin signal generated by the serodyne signal generating means to generate a composite signal of the various phase modulations And may have the following.
  • the bias modulation signal generating means modulates, for example, the first constant output signal generated by the first constant output signal generating means, so that the frequency l / ⁇ (where ⁇ is the optical signal First modulating means for generating a first phase modulation signal consisting of a rectangular wave having a propagation time of light in a fiber loop);
  • the second constant output signal generated by the second constant output signal generating means is modulated to form a second phase modulation signal in which a pulse having a pulse width of / 2 alternately appears at each time interval 2 in a positive and negative manner.
  • Second adding means for generating a signal by adding the constant output signal of
  • the phase difference of the interference light is represented by ⁇ + ⁇ + ⁇ , ⁇ - ⁇ ,- ⁇ __- ⁇ ,- r + ⁇ , ⁇ i ⁇ - ⁇ , ⁇ - ⁇ ⁇ - ⁇ - ⁇ ⁇ , -a + 0, a series of steps in the order,-- ⁇ , ⁇ ⁇ ⁇ ⁇ ,- ⁇ ⁇ , -j- ⁇ - ⁇ , ⁇ _ ⁇ , ⁇ i ⁇ - ⁇ , - ⁇ ⁇ ,- ⁇ -0 + ⁇ 3, a series of steps, a-0 _ ⁇ , a + 0, - ⁇ ⁇ ⁇ , ⁇ _ ⁇ , ⁇ - ⁇ 5, + + 0, ⁇ + 0-(5,- ⁇ - ⁇ Or a series of steps in the following order: a + 0, T- ⁇ - ⁇ ⁇ - ⁇ - ⁇ ,- ⁇ + ⁇ , a + ⁇ , ⁇ - ⁇ ⁇ ⁇
  • FIG. 1 shows an example of the modulation phase difference according to the present invention.
  • the phase difference of the interference light is ⁇ - ⁇ ,- ⁇ - ⁇ _ ⁇ , - ⁇ ,, r ⁇ ⁇ -6, ⁇ - ⁇ ,--- ⁇ . , -End + ⁇
  • the phase difference of the interference light is ⁇ - ⁇ ,- ⁇ - ⁇ _ ⁇ , - ⁇ ,, r ⁇ ⁇ -6, ⁇ - ⁇ ,--- ⁇ . , -End + ⁇
  • 3 shows a modulation phase difference when using a composite signal of various phase modulations obtained by (1) and (2).
  • 0 ⁇ / 2 t, and 0 ⁇ 10 degrees
  • the input angular velocity is set to 0 for simplicity.
  • the phase shift is a + 0 + ⁇ (or f is ⁇ , the light intensity of the interference light detected and the a ⁇ ( Or ⁇ + ⁇ ), the intensity difference from the light intensity of the interference light detected when ⁇ ⁇ -6 (or - ⁇ -0 + ⁇ 5).
  • ⁇ - ⁇ (or-) based on the intensity difference from the light intensity of the interference light detected at or-or (or -0- ⁇ 5). Indirectly propagates the optical fibers in opposite directions based on the difference between the light intensity of the interference light detected at the time of and + 0- ⁇ (or- ⁇ - ⁇ + ⁇ ).
  • the light intensity of the interference light detected when the phase shift is ⁇ + 0 + (5 (or ⁇ )? ), And the difference between the light intensity of the interference light detected at the time of + 0-(5 (or---0 + ⁇ 5)) and the intensity of the interference light.
  • the modulation that occurs during phase shift by the combined signal of various phase modulations Gain error can be detected Therefore, it is possible to control the modulation gain of the composite signal of various phase modulations so that the detected modulation gain error becomes zero, thereby performing accurate modulation control and cellodyne control.
  • the scale factor error in the gyro output can be reduced.
  • the composite signal generating means has the above-described configuration.
  • the modulation gain control means adjusts an output value of the first addition means in accordance with a signal corresponding to a modulation gain error generated by the modulation gain calculation means, so that the various The gain of the composite signal of the phase modulation may be controlled.
  • the first constant output signal generation means, the second constant output signal generation means, and the third constant output signal By adjusting the output value of each constant output signal generated by the signal generation means and the output value of the serodin signal generated by the serodin signal generation means, the gain of the composite signal of the various phase modulations is adjusted. It may be controlled.
  • the output value of the first addition means that is, the amplitude of the synthesized signal itself of various phase modulations generated by the synthesized signal generation means is adjusted. Therefore, it is required to perform arithmetic processing using a multiplier or the like within the time width of each step ( ⁇ / 2 in the example shown in FIG. 1) of the composite signal of various phase modulations.
  • the first constant output signal generation means may change the value according to a change in the light intensity value of the detected interference light.
  • the output value of the first constant output signal may be changed. For example, show the correspondence between light intensity and 0 A table is provided, and by referring to the table, a first constant output signal having an output value necessary for performing a phase shift of ⁇ ⁇ corresponding to the light intensity value of the detected interference light is generated. You may.
  • the random walk value is a function in which the light intensity value of the interference light is a parameter, and if this light intensity value changes, the phase modulation amplitude for minimizing the random walk value also changes. I do. Therefore, by performing the above, it is possible to reduce the influence of the random walk regardless of the change in the light intensity value of the interference light.
  • a switch means connected to an output side of the light receiving means, and a holding means connected to an output side of the switching means are further provided, wherein the switch means
  • the output of the signal detected by the light receiving unit is cut off for a predetermined period in synchronization with the rise and fall of the composite signal of various phase modulations generated by the composite signal generation unit, and the switch is switched by the hold unit.
  • the value of the signal sent from the light receiving means via the means may be maintained for a predetermined time.
  • the switch means and the hold means further, it is possible to remove an error due to an optical spike contained in a signal output from the light receiving means. Can be. Further, during a period in which the switch means blocks the signal sent from the light receiving means (that is, a period in which the error is removed), the signal immediately before the cutoff held in the holding means is held. Output, it is possible to reduce the influence of discontinuous operation due to the interruption of the switch means and to prevent external electromagnetic noise or the like from being mixed in, thereby providing a stable detection signal. Therefore, the operations of the modulation control and the serodin control can be further stabilized.
  • the switch means does not necessarily output the output of the signal sent from the light receiving means in synchronization with all rises and falls of the composite signals of various phase modulations generated by the composite signal generation means. There is no need to shut off for a specified period.
  • the output of the electrical signal may be cut off for a predetermined period in synchronization with only one of the rising and falling of the combined signal that performs a phase shift accompanied by an optical spike.
  • the serrodyne signal generating means when the accumulation result of the modulation phase difference due to the serrodyne signal reaches a first threshold value, the serrodyne signal generating means is reset so as to generate a phase shift of -2 ⁇ , and When the accumulation result of the modulation phase difference due to the cellodyne signal reaches a second threshold which is 27 ° lower than the first threshold, the cellodyne signal generation is performed so as to generate a phase shift of + 2 ⁇ . Reset the means. May be provided.
  • the first threshold value for example, by setting the first threshold value to + ⁇ and the second threshold value to - ⁇ , it is possible to use a serodyne signal as in the digital optical fiber gyro described in the background art above.
  • the peak peak value of the cellodyne signal can be made smaller than when resetting to 0 when the phase shift reaches ⁇ 2 ⁇ . As a result, power consumption can be reduced.
  • a single power supply can be used as a power supply for generating a serodin signal.
  • FIG. 1 is a diagram for explaining the relationship between the light intensity of the interference light and the modulation phase difference in the first embodiment of the present invention.
  • FIG. 2 is a schematic configuration diagram of a digital optical fiber jar opening to which the first embodiment of the present invention is applied.
  • FIG. 3 is a schematic configuration diagram of the spike remover 24 shown in FIG.
  • FIG. 4 is a schematic configuration diagram of the digital signal processor 100 shown in FIG.
  • FIG. 5 is a schematic configuration diagram of the signal processing unit 110 shown in FIG.
  • FIG. 6 is a diagram for explaining a modulation phase difference when an angular velocity is input to the optical fiber loop 6 and a Sannyak phase difference ⁇ s occurs in the phase modulation operation shown in FIG.
  • FIG. 7 is a diagram for explaining a modulation phase difference when an error is included in the modulation gain G of the phase modulation by the phase modulator 5 in the phase modulation operation shown in FIG.
  • FIG. 8 is a diagram illustrating a relationship between a deviation signal (a signal corresponding to a modulation gain error) of a modulation control system and a modulation gain G.
  • FIG. 9 is a schematic configuration diagram of the serodyne control unit 140 shown in FIG.
  • FIG. 10 is a diagram showing an operation flow of the comparator 150 when the first threshold is set to + 2 ⁇ and the second threshold is set to ⁇ 2 ⁇ in FIG.
  • FIG. 11 is a diagram showing an operation flow of the comparator 150 when the first threshold is set to + 2 ⁇ and the second threshold is set to 0 in FIG.
  • FIG. 12 is a diagram showing an operation flow of the comparator 150 when the first threshold is set to + ⁇ and the second threshold is set to ⁇ in FIG.
  • FIG. 13 is a diagram showing a waveform of a serrodyne signal generated by the third computing unit 146 shown in FIG.
  • FIG. 14 is a schematic configuration diagram of the modulation control section 170 shown in FIG.
  • FIG. 15 is a diagram showing a waveform of an output signal in each section of the modulation control section 170 shown in FIG.
  • FIG. 16 is a schematic configuration diagram of the light intensity calculation unit 210 shown in FIG. Figure 17 shows the relative intensity noise RIN of light source 1 at -115 [dB / Hz] and the peak value P of the light intensity of the interference light.
  • FIG. 9 is a diagram showing random walk value phase modulation amplitude value characteristics when the value is set to 2 to 50 aW.
  • FIG. 18 is a schematic configuration diagram of the gyro output operation unit 240 shown in FIG.
  • FIG. 19 is a schematic configuration diagram of a digital signal processor 100a used in an optical fiber jar opening to which the second embodiment of the present invention is applied.
  • FIG. 20 is a schematic configuration diagram of the serodyne control unit 140a shown in FIG. 2
  • t Figure 2 2 is a schematic configuration diagram of a modulation control unit 1 7 0 a shown in FIG. 1 9 is a schematic diagram of a gyro output computing part 2 4 0 a shown in FIG 9.
  • FIG. 23 is a diagram for explaining a modulation phase difference by a conventional gyro.
  • FIG. 24 is a diagram for explaining a modulation phase difference by a conventional gyro.
  • FIG. 25 is a diagram for explaining a modulation phase difference by a conventional gyro.
  • FIG. 2 is a schematic configuration diagram of a digital optical fiber gyro to which the first embodiment of the present invention is applied.
  • reference numeral 500 denotes a light meter.
  • the optical interferometer 500 is composed of a light source 1, a power bra 2, a polarizer 3, a power bra 4, a phase modulator 5, and an optical fiber loop 6 formed by winding an optical fiber a plurality of times. I have.
  • a single palmescent diode (SLD) with a long coherence length or an erbium-doped optical fiber light source (EDFS) with a higher output intensity than the SLD is used.
  • the polarizer 3, the power blur 4, and the phase modulator 5 are integrated on one substrate as an optical integrated circuit (IOC). Also, in Figure 2, one end of the optical fiber loop 6 Although the phase modulator 5 is provided, it may be provided at both ends to perform phase modulation on the optical fiber 6 in directions opposite to each other.
  • the light emitted from the light source 1 passes through the power blur 2 and the polarizer 3 and enters the camera 4 where it is split into two lights.
  • One of these two lights propagates clockwise in the optical fiber loop 6, is phase-modulated by the phase modulator 5, and returns to the power blur 4.
  • the other propagates counterclockwise through the optical fiber loop 6, is phase-modulated by the phase modulator 5, and returns to the power blur 4.
  • both are combined by the force bra 4. Thereby, interference light is formed.
  • ⁇ s (2 ⁇ DL / ⁇ c) ⁇ (1)
  • D is the diameter of the optical fiber loop 6
  • L is the length of the optical fiber
  • ⁇ is the wavelength of light emitted from the light source 1
  • c is the speed of light It is.
  • the light intensity ⁇ ⁇ of the interference light and the Sagnac phase difference ⁇ s have the following relationship.
  • ⁇ ( ⁇ 0/2) (Hcos ⁇ s) (2) where ⁇ . Is the peak value of the light intensity of the interference light.
  • the interference light formed by the force blur 4 is received by the light receiver 7 and converted into a current signal corresponding to the light intensity of the interference light.
  • This current signal is converted into a voltage signal by a current / voltage (I / V) converter 8 and then amplified by a wideband amplifier 9.
  • the voltage signal amplified by the amplifier 9 is removed by a DC remover 20 composed of a high-pass filter and a DC offset adder, and then amplified by a wide-band amplifier 22. .
  • the spike remover 24 removes the component due to the optical spike contained in the signal.
  • the spike remover 24 includes a switch and a low-pass filter (LPF). The details will be described later.
  • the voltage signal from which the optical spike component has been removed by the spike remover 24 is input to the A / D converter 26 for serodyne control and modulation control, where the sampling from the reference signal generator 300 is performed. According to the signal D, it is sampled and converted to a digital signal.
  • the sampling period of the sampling signal differs depending on the time constant of the LPF constituting the spike remover 24, but at least the duration of each step of the composite signal of various phase modulations described later (in this embodiment, / 2) must be shorter.
  • ⁇ is the propagation time of light in the optical fiber loop 6, which is the optical fiber length of the optical fiber loop 6, the refractive index ⁇ 0 of the optical fiber constituting the optical fiber loop 6, and the light speed c. Is expressed by the following equation.
  • the digital signal processor 100 uses the gyro output (rotation Angular velocity or rotation angle) is calculated.
  • the digital signal processor 100 determines that the phase difference of the interference light is ( ⁇ + ⁇ ) ⁇ ( ⁇ ) ⁇ ( ⁇ ) ⁇ ⁇ - ⁇ ⁇ ⁇ ) ⁇ ⁇ ⁇ - ⁇ ) ⁇ ( ⁇ - ⁇ ) ⁇ (-7- ⁇ ⁇ ) ⁇ (- ⁇ ⁇ ⁇ ) (Repeat a series of steps in D order (period 4 and the duration of each step / 2) Do phase modulation And a stepped cellodyne signal with the same duration as the calculated Sanyak phase difference ⁇ s and the duration of each step ⁇ or ⁇ / 2 to produce a phase difference of the opposite sign. Generates composite signals of various phase modulations.
  • k is an odd number: 0 ⁇ 0 ⁇ ⁇ / 2
  • k is an even number: 7T / 2 ⁇ 0 ⁇ 7 ⁇
  • the amplitude 0 of the phase shift of the bias modulation signal is determined in accordance with the light intensity value of the interference light so that the random walk value is minimized.
  • the phase modulation amplitude for minimizing the random walk value is said to be in the range of ⁇ / 2 to less than 7 °.
  • the random walk value is a function that makes the light intensity value of the light beam a parameter over time, and if this light intensity value changes, the phase modulation amplitude for minimizing the random walk value also changes. .
  • a table showing the relationship between the light intensity value of the interference light and the phase modulation amplitude for minimizing the random walk value is prepared, and referring to the table, the detection of the interferometer 500 is performed. The amplitude ⁇ corresponding to the light intensity value of the interference light obtained from the result is determined.
  • the phase difference of the interference light is changed.
  • a first threshold value for example, + ⁇
  • the phase difference of the interference light is changed.
  • -Modulation phase by serodin signal reset to 2 ⁇ phase shift
  • the phase difference of the interference light is reset to a phase shift of + 2 ⁇ . This prevents the output of the serodin signal from increasing indefinitely.
  • the composite signal of various phase modulations generated in the digital signal processor 100 is converted into an analog signal in the D / A converter 10 and then transmitted to the phase modulator 5 through the driver 11. Is entered.
  • the phase modulator 5 performs phase modulation on the two lights propagating in the optical fiber loop 6 in opposite directions, respectively, according to the composite signal of various phase modulations.
  • the modulation phase difference generated between two lights propagating in the optical fiber loop 6 in opposite directions to each other and the light intensity of the interference light obtained by recombining the two lights. explain the relationship.
  • FIG. 1 shows a modulation phase difference by the optical fiber gyro of the present embodiment.
  • ⁇ ⁇ 6 10 degrees.
  • the phase shift is equal to the optical intensity of the interference light detected when a + ⁇ + ⁇ (or-
  • the serodin control system including the digital signal processor 100, the optical interferometer 500, the light receiver 7, etc.
  • AGC Automatic Gain Control 1
  • the light intensity of the interference light detected when the phase shift is 7 + ⁇ + ⁇ (or ⁇ 0 ⁇ ) and ⁇ (Or -a + 0), the difference between the light intensity of the interference light detected at the time of (a + 0), and the light intensity of the interference light detected at a + ⁇ (or- Based on the intensity difference from the light intensity of the interference light detected at (+0), a modulation gain error generated at the time of phase shift by the bias phase modulation signal can be detected.
  • a table showing the relationship between the light intensity value of the interference light and the phase modulation amplitude for minimizing the random walk value refer to the table to determine the interference light obtained from the detection result of the interferometer 500.
  • the above-described bias modulation signal is generated so that the amplitude becomes 0 corresponding to the light intensity value.
  • the spike remover 24 is provided to remove an erroneous difference due to an optical spike included in the detection signal of the interference light output from the light receiver 7.
  • FIG. 3 is a schematic configuration diagram of the spike remover 24.
  • the spike remover 24 includes a switch 40, a low-pass filter (LPF) / hold circuit 42 including a resistor and a capacitor, and an amplifier 46.
  • LPF low-pass filter
  • the switch 40 cuts off the output of the voltage signal sent from the amplifier 22 for a predetermined period according to the signal E generated by the reference signal generator 300.
  • the signal E has a frequency of 1 / This is a reference signal synchronized with the composite signal of various phase modulations generated by the signal processor 100.
  • the cutoff period is set in consideration of the time of occurrence of the optical spike of the interference light.
  • the LPF / hold circuit 42 removes white noise components and other high-frequency electromagnetic noise contained in the voltage signal sent via the switch 40. I do.
  • the switch 40 is off (cut off)
  • the voltage signal immediately before the cutoff is held by the electric charge stored in the capacitor constituting the LPF / hold circuit 42. This voltage signal is output to the A / D converter 26 via the amplifier 46.
  • the LPF / hold circuit 42 can reduce the influence of discontinuous operation due to the ON / OFF of the switch 40, and can prevent external noise such as electromagnetic noise from being mixed. Can be. As a result, stable signal detection can be performed, so that the operations of modulation control and port din control can be further stabilized.
  • the A / D converter 26 achieves the best gyro output with the minimum number of samplings. Can be obtained. In other words, since it is not necessary to perform extreme oversampling, the processing speed of the A / D converter 26 and the digital signal processor 100 can be reduced compared to conventional optical fiber gyros. This makes it possible to configure the optical fiber jar opening with less expensive parts.
  • the voltage signal is sufficiently converted by the amplifier 22. After amplification, the optical spike is removed by the spike remover 24. In this configuration, since the voltage signal is sufficiently amplified, the effect of noise generated by turning on / off the switch 40 can be effectively reduced, and more stable signal detection can be performed. This is a favorable configuration.
  • the amplifier 46 has a buffer configuration, the output of the LPF / hold circuit 42 may be directly input to the / 0 converter 26 without using the amplifier 46.
  • the spike remover 24 has been described above.
  • FIG. 4 is a schematic configuration diagram of the digital signal processor 100.
  • the digital signal processor 100 includes a signal processing unit 110, a serrodyne control unit 140, a modulation control unit 170, and a light intensity calculation unit 210. And a gyro output operation unit 240.
  • a signal processing unit 110 a serrodyne control unit 140, a modulation control unit 170, and a light intensity calculation unit 210.
  • a gyro output operation unit 240 Each of these configurations may be realized by an integrated logic IC such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA), or It may be realized by software using a computer such as a DSP (Digital Signal Processor). Further, the specific processing in each configuration is not limited to those described below, and may be any processing as long as the same function can be realized.
  • ASIC application specific integrated circuit
  • FPGA field programmable gate array
  • DSP Digital Signal Processor
  • the signal processing unit 110 adjusts the gain of the signal output from the A / D converter 26 and demodulates it.
  • FIG. 5 is a schematic configuration diagram of the signal processing unit 110 shown in FIG.
  • the multiplier 1 3 4 is composed of the output signal of the A / D converter 26 and the light intensity calculator 2 1 0 Multiplication with AGC (Automatic Gain Control) signal from Thereby, the gain of the output signal of the A / D converter 26 is adjusted so as to be always constant. By doing so, it is possible to stabilize the operations of the serodyne control unit 140, the modulation control unit 170, and the light intensity calculation unit 210, and, consequently, the rotation angular velocity or rotation angle of the gyro. It can output stably.
  • AGC Automatic Gain Control
  • an analog multiplier may be used in place of the multiplier 134.
  • the analog multiplier is placed before the A / D converter 26.
  • the AGC signal from the light intensity calculator 210 is converted to an analog signal by the D / A converter, and then input to the analog multiplier, where it is input to the A / D converter 26. It is adjusted so that the gain of the voltage signal is always constant.
  • the first demodulator 1 1 2 uses the reference signal B (frequency signal 1 /, for example, a pulse signal having two values of ⁇ 1) generated by the reference signal generator 3 0 0 to generate a multiplier 13 4. Demodulate the output signal of 4.
  • This demodulator is composed of, for example, a multiplier.
  • the sampling interval at the A / D converter 26 is shorter than / 2, that is, when the sampling point is at two or more places during the / 2 period, the A / D converter 26 and A filter for performing an averaging process is provided between the first demodulator 112 and the first demodulator 112 so that the input signal to the first demodulator 112 is output at an interval of ⁇ / 2.
  • the second demodulator 1 14 generates the first demodulator by the reference signal ⁇ (pulse signal having a frequency of 1/2 and having a binary value of ⁇ 1, for example) generated by the reference signal generator 300. Demodulate the output signal of 1 1 2.
  • This demodulator is composed of, for example, a multiplier.
  • the first computing unit 1 16 averages and outputs the output of the second demodulator 114 at every time 2 or 4 by taking the sum of the outputs shifted by time. This output is a deviation signal of a closed-loop serodyne control system including the serodyne controller 140.
  • the output (detection signal) of the / 0 converter 26 is demodulated at the frequency 1 / by the first demodulator 112, and the demodulation result is obtained by the second demodulator 114.
  • the sign of the demodulated detection signal changes from (+) to (-) to (-) to (+) at every ⁇ in the two periods. Therefore, by taking the sum of the deviated outputs, it is possible to extract a signal (deviation signal of the serodyne control system) corresponding to the saniac phase difference ⁇ s required for generating the serodyne signal. .
  • the second computing unit 122 sets the phase shift of the output signal of the multiplier 1334 to a + 0 + ⁇ (or ⁇ a ⁇ ) in the first 2r period. 0- ⁇ ) and the signal corresponding to the light intensity of the interference light detected at a-0 (or- ⁇ + 0). X is detected, and the average Xave of the detection results is obtained.
  • the phase shift force the signal corresponding to the light intensity of the interference light detected when r + ⁇ -(5 (a certain value is-a-6 »+ ⁇ ), and the a-0 ( Alternatively, the difference ⁇ from the signal corresponding to the light intensity of the interference light detected at ⁇ ) is detected, and the average Z ave of the detection result is obtained.
  • the output of 2 2 alternates every two periods, such as X ave , Z ave , X tract,,, Z ,,.
  • the third computing unit 124 generates a signal satisfying the following expression based on the output signals X ave and Z ave of the second computing unit 122.
  • This signal is a deviation signal of a modulation control system which is a closed loop including the modulation control section 170. This deviation signal is output to modulation control section 170.
  • the modulation gain G of the phase modulation by the phase modulator 5 includes an error.
  • the modulation phase difference is as shown in FIG.
  • the gain of the composite signal can be adjusted.
  • FIG. 8 shows the relationship between the above equation (4) and the modulation gain G, and the relationship between the differences X and Z and the modulation gain G. As can be seen from this figure, when the above equation (4) is 0, the modulation gain G becomes 1.
  • this deviation signal is generated by a modulation controller 170 described later when the gain of the phase modulator 5 or the D / A converter 10 changes due to temperature change or aging. This is for adjusting the gain of the phase modulation composite signal. Therefore, the control loop of the modulation control system operates at high speed. There is no need to be. Further, the arithmetic processing in the third arithmetic unit 124 may be performed in the msec order.
  • the fourth computing unit 1336 generates a signal satisfying the following expression based on the output signals X ave and Z ave of the second computing unit 122.
  • Signal X ave -Z ave (5)
  • the signal calculated by the above equation (5) is the peak value P of the light intensity of the interference light. Becomes a signal proportional to. This signal is sent to the light intensity calculator 210 as a signal Yave .
  • the serodyne control unit 140 generates a mouth din signal in accordance with the signal corresponding to the saniac phase difference ⁇ s output from the first computing unit 116 of the signal processing unit 110.
  • FIG. 9 is a schematic configuration diagram of the serrodyne controller 140 shown in FIG.
  • the first computing unit 142 integrates the signal corresponding to the saniac phase difference ⁇ s sent from the signal processing unit 110 at two or four time intervals. The result is a signal proportional to the input angular velocity to the optical fiber loop 6.
  • the second computing unit 144 functions as an amplifier or a single pass filter.
  • the gain or filter constants are set according to the design of the serodyne control loop.
  • the third computing unit 146 integrates the output signal of the first computing unit 142 sent through the second computing unit 144 at a time interval of 1/2.
  • the output signal of the first computing unit 142 is a signal proportional to the input angular velocity to the optical fiber 6. If the input angular velocity is constant, the output signal of the first computing unit 142 also becomes constant.
  • the third The output result of the arithmetic unit 146 is a staircase signal having a constant height with a duration of each staircase of / 2. This staircase signal is output to the modulation control section 170 as a serrodyne signal.
  • the comparator 150 outputs the first threshold value or the second threshold value which is lower by 2 t than the first threshold value, when the accumulation result of the modulation phase difference by the serodin signal output from the third computing unit 146 is obtained. It is determined whether the threshold has been reached. Then, when the first threshold value is reached, the third computing unit 146 is reset so that the phase difference of the light is a phase shift of ⁇ 2 ⁇ . When the second threshold value is reached, the third computing unit 146 is reset so that the phase difference of the light beam becomes a phase shift of + 2 ⁇ .
  • FIG. 10 shows an operation flow of the comparator 150 when the first threshold is set to + 2 ⁇ and the second threshold is set to ⁇ 2 ⁇ .
  • the comparator 1500 determines whether or not the accumulation result of the modulation phase difference due to the serodyne signal generated by the third computing unit 144 has reached 2 ⁇ (step 1001). .
  • step 1002 When the value reaches 2 ⁇ , it is determined that a phase shift (negative reset) of -2 ⁇ is performed (step 1002). Thereafter, a command is issued to the third computing unit 144 so that the phase difference of the interference light becomes a phase shift of -2 ⁇ (step 1003). In response to this, the third computing unit 146 adjusts the output of the serodyne signal so that the phase difference of the interference light becomes a phase shift of -2 ⁇ .
  • step 1004 it is determined whether or not the accumulation result of the modulation phase difference by the serodin signal has reached ⁇ 2 ⁇ (step 1004) ;
  • Step 1 0 5
  • a command is issued to the third computing unit 146 so that the phase difference of the interference light becomes a phase shift of + 27T (step 106).
  • the third computing unit 146 adjusts the output of the cellodyne signal so that the phase difference of the interference light becomes a phase shift of + 2 ⁇ .
  • step 107 if the temperature has not reached -27C, it is determined that reset is not necessary (step 107). In this case, no phase shift command is output to the third computing unit 144.
  • FIG. 11 shows an operation flow of the comparator 150 when the first threshold is set to + 2 ⁇ and the second threshold is set to 0.
  • step 1004a is provided instead of step 104, where the accumulation result of the modulation phase difference due to the serrodyne signal is obtained.
  • FIG. 12 shows an operation flow of the comparator 150 when the first threshold is set to + 7t and the second threshold is set to ⁇ 7t. This flow differs from the flow shown in FIG. 10 in that steps 1001 a and 1004 b are provided instead of steps 1001 and 104.
  • step 1001a it is determined whether or not the accumulation result of the modulation phase difference by the serodin signal has reached + ⁇ . If the value has reached + ⁇ , the process proceeds to step 1002; otherwise, the process proceeds to step 104b.
  • step 104b the accumulation of the modulation phase difference by the serodin signal Determine whether the product result has reached - ⁇ . -If it has reached ⁇ , go to step 1005; otherwise, go to step 1007.
  • FIG. 13 shows the waveform of the serrodyne signal generated by the third computing unit 146.
  • FIG. 13 (a) shows the waveform of the serrodyne signal generated by the third computing unit 146 according to the flow shown in FIG. 10
  • FIG. 13 (b) shows the waveform of FIG.
  • FIG. 13 (c) shows the waveform of the serrodyne signal generated by the third computing unit 146 according to the flow shown in FIG.
  • a serodin signal can be generated with a single polarity regardless of the polarity of the input angular velocity to the optical fiber loop 6. This makes it possible to configure a D / A converter and driver for generating serodin signals with a single power supply.
  • the digital signal processor 100 and the reference signal generator 300 operate on a single power supply such as +5 V, so if the D / A converter 10 can operate on a single power supply, This makes it possible to reduce the size and cost of the equipment.
  • step 1001 it is determined whether or not the accumulation result of the modulation phase difference due to the serodin signal has become larger than 0. The same effect can be obtained by judging whether or not the accumulation result of the modulation phase difference due to the signal has become ⁇ 2 ⁇ or less.
  • the peak-to-peak value of the serodyne signal is reduced by half compared to the flow shown in FIG. This allows The power consumption at the terminating resistor of the phase modulator 5 can be reduced to 1/4.
  • the fourth computing unit 152 includes a reference signal (a signal corresponding to the modulation gain error specified by the above equation (4)) for the modulation gain control generated by the modulation control unit 170 described later. Is set to 0, that is, based on the reference signal whose output value is corrected so that the modulation gain G becomes 1), the first and second threshold values used in the comparator 150 are specified. And outputs a value for specifying the amount of phase shift due to the reset in the third calculator 146. For example, if the reference signal has an output value necessary to perform a phase shift of 2 ⁇ , a value for specifying the first and second thresholds from the output value of this reference signal and a phase shift due to reset are used. Calculate and output the value to specify the quantity.
  • a reference signal a signal corresponding to the modulation gain error specified by the above equation (4)
  • the fourth computing unit 152 outputs, to the gyro output computing unit 240, a scale factor correction value required for gyro output computation required for controlling the modulation gain by the reference signal.
  • the modulation control section 170 performs the first constant output signal having a value necessary to perform the phase shift of 0 by modulating the first constant output signal.
  • a pulse with a pulse width of / 2 obtained by modulating a phase modulation signal and a second constant output signal having a value required to perform a phase shift of ⁇ alternates between positive and negative at every time interval of 2.
  • the second phase-modulated signal appearing in the signal and the third constant output signal having a value necessary for performing the phase shift of the signal are synthesized, and this is modulated at half the frequency to obtain the interference light.
  • phase difference force ( ⁇ ( ⁇ ⁇ ⁇ )) ⁇ ( ⁇ - ⁇ ) ⁇ (- ⁇ - ⁇ - ⁇ ) ⁇ (- ⁇ ) ⁇ ( ⁇ ⁇ ⁇ - ⁇ ) ⁇ ( ⁇ -(- ⁇ - ⁇ + ⁇ 5) ⁇ (-
  • a bias modulation signal for performing phase modulation so as to repeat the duration of each step / 2) is generated.
  • the bias modulation signal generated as described above and the serodin signal generated by the serrodyne control unit 140 are combined to generate a combined signal of various phase modulations.
  • FIG. 14 is a schematic configuration diagram of the modulation control section 170 shown in FIG.
  • the reference value storage unit 196 stores a reference value (for example, 2 ⁇ phase shift) for generating an output value required for performing phase shifts of ⁇ , ⁇ , and ⁇ 5. Output value necessary for this) is stored, and this value is output as a reference signal.
  • a reference value for example, 2 ⁇ phase shift
  • the first computing unit 172 integrates the deviation signal of the modulation control system (the signal corresponding to the modulation gain error specified by the above equation (4)) sent from the signal processing unit 110. Integrator.
  • the second computing unit 174 is an amplifier or a low-pass filter. Design the gain or fill constant according to the design of the modulation loop control system.
  • the third computing unit 190 adjusts the reference signal outputted from the reference value storage unit 196 according to the deviation signal of the modulation control system outputted from the second computing unit 174. For example, if the deviation signal of the modulation control system has a positive value, the output value of the reference signal (for example, the value required to perform a 2 ⁇ phase shift) is adjusted to be small, and modulation control is performed. If the deviation signal of the system has a negative value, adjust so that the output value of the reference signal increases.
  • the deviation signal of the modulation control system becomes zero by the operation of the modulation control system (servo loop), that is, the modulation gain Generate a reference signal whose output value is corrected so that G becomes 1.
  • the third computing unit 190 for example, an adder is used.
  • the amplitude 0 generator 202 Based on the reference signal whose output value has been corrected by the third computing unit 190, the amplitude 0 generator 202 has the phase of the phase modulation amplitude value 0 sent from the light intensity computing unit 210. Generates a constant output signal with the value needed to perform the shift. For example, if the reference signal has an output value necessary to perform a phase shift of 2 ⁇ , it is necessary to perform the phase shift of ⁇ determined by the light intensity calculator 210 from the output value of this reference signal. Calculate and output necessary values.
  • the amplitude ⁇ generator 180 is a constant output signal having a value necessary for performing a phase shift of ⁇ 5 based on the reference signal whose output value has been corrected by the third computing unit 190. Generate For example, if the reference signal has an output value required to perform a 2 ⁇ phase shift, the value required to perform a ⁇ phase shift is calculated from the output value of the reference signal and output.
  • the amplitude generator 208 generates a constant output signal having a value necessary for performing a phase shift of the key based on the reference signal whose output value has been corrected by the third arithmetic unit 190. Generate. For example, if the reference signal has an output value necessary for performing a 2 ⁇ phase shift, a value necessary for performing a phase shift of the key is calculated from the output value of the reference signal and output.
  • the phase modulation generator 204 generates an amplitude 0 generator 204 according to the reference signal generated by the reference signal generator 300 (pulse signal having a binary value of 1 / frequency, for example, ⁇ 1).
  • the constant output signal generated in step 2 is modulated, thereby generating a first phase modulation signal having a rectangular wave having a frequency of 1 /.
  • This phase modulation generator 204 is constituted by, for example, a multiplier.
  • ⁇ 3 Modulation generator 18 2 is the same as that generated by reference signal generator 300
  • a pulse signal that repeats a series of steps, 1 ⁇ 0—0 ⁇ 0, with a duration of each step of / 2 is generated by the reference signal generator 300.
  • Modulated with the reference signal C (frequency 1/4 ⁇ , for example, a binary pulse signal of ⁇ 1).
  • a pulse signal that repeats a series of steps 1 ⁇ 0 ⁇ 0 ⁇ 0 ⁇ ⁇ 1 ⁇ 0 ⁇ 0 ⁇ ⁇ 0 with a duration of / 2 for each step is generated.
  • the modulation generator 182 modulates the constant output signal generated by the amplitude ⁇ generator 180 according to the generated pulse signal, and thereby, the pulse width /
  • a second phase modulation signal is generated in which two pulses alternate in the positive and negative directions at every two time intervals.
  • the adder 206 includes a first phase modulation signal generated by the phase modulation generator 204, a second phase modulation signal generated by the ⁇ modulation generator 18 2, and an amplitude generator 2 0 Adds the constant output signal generated in step 8 in synchronization.
  • Modulation generator 200 uses the reference signal ⁇ (pulse signal that takes two values of ⁇ 1 at the operating point switching frequency 1/2 of the phase modulation) generated by reference signal generator 300. Then, the output signal of the adder 206 is modulated. As a result, the phase difference of the interference light becomes ( ⁇ + ( ⁇ ⁇ ⁇ 5)
  • the adder 176 generates a bias modulation signal for performing phase modulation so as to repeatedly take the duration of / 2) of the bias modulation signal generated by the modulation generator 200.
  • the adder 176 By adding the serodin signal generated by the serodin control unit 140 to generate a composite signal of various phase modulations.
  • FIG. 15 shows the output signal waveforms at each section of the modulation control section 170.
  • Fig. 15 (a) shows the waveform of the output signal (first phase modulation signal) of the phase modulation generator 204
  • Fig. 15 (b) shows the waveform of the output signal of the 5 modulation generator 182 (second signal).
  • Figure 15 (c) shows the output signal waveform of the adder 206
  • Figure 15 (d) shows the output signal of the modulation generator 200 (bias modulation signal). Shows the waveform.
  • the first phase-modulated signal shown in FIG. 15 (a) has a symmetric waveform with respect to time ⁇ , and the difference between signals shifted by ⁇ is zero. Since the phase difference between two lights propagating in the optical fiber loop 6 in opposite directions occurs between the two lights that are shifted in time, the first phase modulation signal shown in Fig. 15 (a) No phase difference can be generated in light. That is, no phase modulation is applied.
  • the bias modulation signal shown in Fig. 15 (d) is composed of the first phase modulation signal shown in Fig. 15 (a), the second phase modulation signal shown in Fig. 15 (b), and the amplitude generator 208.
  • This signal is a signal obtained by synchronizing and adding the constant output signal generated in (1) (the signal shown in Fig. 15 (c)) at half the frequency. By modulating at a frequency of 1/2, the polarity of the bias-modulated signal alternates every time and generates a phase difference of interference light generated between the signals shifted by ⁇ time.
  • phase difference of the interference light is changed by (a + 0 + ⁇ ) ⁇ (a- ⁇ ) ⁇ (- ⁇ - ⁇ - ⁇ ) ⁇ ( - ⁇ ⁇ ⁇ ) ⁇ ( ⁇ ⁇ ⁇ - ⁇ ) ⁇ ( ⁇ - ⁇ ) ⁇ (- ⁇ + ⁇ )
  • the phase modulation can be performed so that the duration / 2) is repeated.
  • phase difference between two lights propagating in the optical fiber loop 6 in opposite directions occurs between the two lights that are shifted in time.
  • the phase modulator 5 By setting the phase modulator 5 to perform the phase shift of S / 2 as the phase modulation signal of the phase shifter, the phase shift of the amplitude 0 is generated in the phase difference of the interference light. be able to.
  • the phase difference of the interference light is (+ ⁇ ) ⁇ 0 ⁇
  • a series of phase shifts of ( ⁇ ) ⁇ 0 ⁇ ( ⁇ ⁇ 5) ⁇ 0 ⁇ (+ ⁇ ) ⁇ 0 can be repeatedly generated.
  • phase modulator 5 by setting the phase modulator 5 to perform the phase shift of a / 2 as a constant output signal necessary for performing the phase shift of the above a, The phase shift of the amplitude can be generated in the phase difference of the light.
  • the light intensity calculator 210 is a peak value ⁇ of the light intensity of the interference light obtained by the fourth calculator 136 of the signal processor 110.
  • the interference light based on the signal Y avt , which is proportional to, and the constant output signals output from the modulation control unit 170 and having the values required to perform the phase shifts of 0, ⁇ , and ⁇ .
  • Peak light intensity ⁇ . Ask for.
  • the peak value ⁇ obtained by referring to a table prepared in advance showing the correspondence between the peak value of the light intensity of the interference light and the optimal phase modulation amplitude that minimizes the random walk value. Determine the amplitude value 0 of phase modulation according to.
  • the light intensity calculator 210 calculates the obtained peak value ⁇ . Based on this, an AGC signal is generated to keep the loop gain of the cellodyne control system constant. This AGC signal is output to the multiplier 13 4 of the signal processing unit 110 described above. It is.
  • the light intensity calculator 210 calculates the peak value of the light intensity of the interference light and the scale factor correction coefficient for correcting the input / output scale factor error of the optical fiber gyro prepared in advance. Peak value P obtained by referring to the table showing the correspondence between Determine the scale factor correction coefficient according to.
  • FIG. 16 is a schematic configuration diagram of the light intensity calculation unit 210 shown in FIG.
  • the first computing unit 2 1 2 is the peak value P of the light intensity of the interference light obtained by the fourth computing unit 1 36 of the signal processing unit 110.
  • ⁇ 0 Y ave / (-sin ⁇ ⁇ sin ( ⁇ + 0)) (6)
  • ⁇ ⁇
  • This arithmetic processing does not need to be performed at high speed. Processing may be performed at intervals of about msec. Therefore, the signal Y ave obtained by the fourth computing unit 1336 of the signal processing unit 110 is averaged, and the peak value of the light intensity of the interference light is calculated by the above equation (6) using the averaged value. Value P. You may ask for
  • the second computing unit 2 14 stores a table indicating the correspondence between the peak value of the light intensity of the interference light and the optimal phase modulation amplitude that minimizes the random walk value. Then, the peak value P of the light intensity of the light beam calculated by the first computing unit 2 12. The optimum phase modulation amplitude according to the above is searched from the table, and this is set as the phase modulation amplitude value 0, and Outputs to the amplitude 0 generator 202 of the controller 170.
  • the resister 216 stores, as an initial value, the peak value of the light intensity of the interference light first calculated by the first computing unit 212 when the interferometer 500 is assembled.
  • the third computing unit 218 is a peak value P of the light intensity of the interference light obtained by the first computing unit 221. And the initial value stored in Regis 2 16 are calculated.
  • the fourth computing unit 220 integrates the result of the third computing unit 218.
  • the result of the integration is output as an AGC signal to the multiplier 1334 of the signal processing unit 110.
  • the fifth computing unit 222 has a correspondence relationship between the peak value of the light intensity of the interference light and the scale factor correction coefficient for correcting the input / output scale factor error of the optical fiber gyro. Is stored. Then, the peak value P of the light intensity of the interference light calculated by the first computing unit 2 12. The scale factor correction coefficient corresponding to the above is retrieved from the table and output to the gyro output operation unit 240.
  • the relationship between the peak value of the light intensity of the interference light and the optimal phase modulation amplitude that minimizes the random walk value will be described.
  • the relationship between the peak value of the light intensity of the interference light and the scale factor correction coefficient for correcting the input / output scale factor error of the optical fiber gyro will be described later.
  • a signal corresponding to the light intensity of the interference light detected by the optical fiber gyro is superimposed with several types of random noise as described below.
  • RIN relative intensity noise
  • the output light of the interferometer 500 with the RIN superimposed thereon is converted into a current signal by the photodetector 7, and at this time, the shot noise correlated with the output value of the converted signal is superimposed. You.
  • This shot noise is defined as follows.
  • N '"[Vrms Pas Hz 1/2)] ⁇ ( 4 ⁇ k ⁇ R ⁇ T) 1/2 (12) N' VN [Vrms / (Hz 1, 2)] ⁇ (V ,. 2 + ( ⁇ R) 2 ) 1 , 2 (13) where k is the Boltzmann constant ( 1.38X10 [] / "K]), R is the resistance [ ⁇ ] of the current-Z voltage converter 8, and T Represents the absolute temperature [° K], and N 'is the effective value of noise defined only in the real number domain. Is the voltage noise of the operational amplifier, and is the current noise. N 'v, is the effective value of the noise that is defined only in the real domain.
  • the angular velocity ⁇ [rad / s] is input to the optical fiber loop 6, and that a saniac phase difference ⁇ s [rad] is generated.
  • the light intensity of the interference light according to the phase difference ⁇ s is Detection is performed by phase-modulating two lights propagating in the fiber loop 6 in opposite directions with amplitude ⁇ [rad].
  • ⁇ ⁇ 1 ( ⁇ (+ ⁇ ) - ⁇ (- ⁇ ))
  • the random walk value is the peak value P of the light intensity of the interference light.
  • the phase modulation amplitude as a parameter.
  • the peak value P of the light intensity of the interference light If the value changes, the phase modulation amplitude that minimizes the random walk value also changes.
  • Figure 17 shows the random walk value versus the phase modulation amplitude value when the relative intensity noise RIN of light source 1 is -115 [dB / Hz] and the peak value P Q of the interference light is 2 to 50 W. Is shown.
  • the above equation (20) The peak value P of the light intensity of the interference light obtained from the equation (21).
  • a table indicating the correspondence between the random phase value and the optimum phase modulation amplitude that minimizes the random peak value is stored in advance, and the peak value P of the light intensity of the interference light calculated by the first computing unit 221. Is searched from the table for the optimum phase modulation amplitude corresponding to.
  • the gyro output operation unit 240 sends the signal to the optical fiber loop 6 according to the signal corresponding to the saniac phase difference ⁇ s sent from the first calculator 142 of the serodyne control unit 140. Calculate the input rotation angular velocity or rotation angle of.
  • FIG. 18 is a schematic configuration diagram of the gyro output operation unit 240 shown in FIG.
  • the first computing unit 242 calculates the phase difference ⁇ s of the saniac transmitted from the first computing unit 142 of the serrodyne control unit 140, that is, the input rotation angular velocity to the optical fiber pump 6.
  • the corresponding signal is integrated over time. This result is proportional to the rotation angle of the optical fiber loop 6.
  • the integration result may be further divided by the integration time.
  • the register 244 stores the input / output scale factor value in the initial state of the optical fiber gyro.
  • the second computing unit 246 stores the scale factor value stored in the register 244, the scale factor correction coefficient sent from the fifth computing unit 222 of the light intensity computing unit 210, Signal generated by the third computing unit 190 of the modulation control unit 170 sent from the fourth computing unit 152 of the control unit 140 (the reference signal whose output value has been correctly corrected) ) By The output of the first computing unit 242 is corrected using the scale factor correction value required for the modulation gain control. Thereby, the input rotation angular velocity or rotation angle to the optical fiber loop 6 is calculated.
  • the second computing unit 246 is constituted by, for example, a multiplier.
  • the output value of the optical fiber gyro (specifically, the rotation angular velocity or rotation angle calculated by the gyro output calculation unit 240) is the peak value P of the light intensity of the interference light. Changes in correlation with the change in This is thought to be due to the following reasons.
  • Gyro output with respect to the input rotational angular velocity ⁇ to the optical fiber loop 6
  • the angle increment in the calculation unit 240 is set to 0 angle
  • the angle when a phase shift of 2 ⁇ occurs due to the reset of the serodin signal The increment 0 sngle is expressed by the following equation.
  • Anganglc c ⁇ ⁇ ⁇ and can be expressed as / D / L (23).
  • the peak value of the light intensity of the interference light ⁇ Changes occur when the loss in the optical path from the light source 1 to the optical receiver 7 via the optical fiber loop 6 changes, and their loss characteristics differ depending on the wavelength of light.
  • the light source 1 used for the optical fiber gyro has a short coherence length and a short wavelength as described above.
  • the vector characteristics are widely distributed over tens to hundreds of nm. Therefore, the light intensity changes due to the change in loss, and the effective center-of-gravity wavelength value of the light changes.
  • the value of the center-of-gravity wavelength ⁇ in the above equations (2 2) and (2 3) changes, and the angle increment 0 angle changes. This is considered to be an input / output scale factor error.
  • the present inventors have confirmed that the sensitivity of the scale factor was about several tens to several hundreds of ppm for a change of the light intensity value of 10%. Light intensity values easily change due to temperature, aging, and the like. This cannot be used for high-performance optical fiber gyros that require a scale factor error of several to several tens of ppm or less.
  • the peak value of the light intensity of the interference light and the scale factor correction coefficient (registration coefficient 24 (A correction coefficient of the scale factor value stored in the optical intensity calculator) is stored in advance, and the peak of the light intensity of the interference light calculated by the first calculator 212 of the light intensity calculator 210 is stored.
  • the scale factor correction coefficient corresponding to the value is retrieved from the table.
  • the second computing unit 246 of the gyro output computing unit 240 the scale factor value stored in the register is corrected using the searched correction coefficient (specifically, the register factor is used).
  • the result obtained by multiplying the scale factor value stored in the gyro by the correction coefficient is converted to the result corresponding to the rotation angle or the average angular velocity output from the first computing unit 242 of the gyro output computing unit 240. Multiply).
  • the phase difference of the interference light is ( ⁇ ⁇ ⁇ ) ⁇ ( ⁇ ) ⁇ ( ⁇ - ⁇ ⁇ ) ⁇ ( ⁇ ) ⁇ ⁇ ⁇ - ⁇ ) ⁇ ( ⁇ -0) ⁇ (- ⁇ -0 + (5) ⁇ (- ⁇ + 0))
  • Repeat a series of steps (period 4, duration of each step / 2)
  • the duration of each staircase which produces a bias modulation signal for performing phase modulation and a phase difference of the same amount and opposite sign as the phase difference ⁇ s of the saniac phase according to the input angular velocity to the optical fiber jar opening
  • the signal is combined with a / 2 step-like serodyne signal to generate a combined signal of various phase modulations, which is input to the phase modulator 5.
  • the signal processing section 110 what is the light intensity of the 1,000 m light detected when the phase shift is ⁇ + 0 + ⁇ 5 (or ⁇ 0 ⁇ )? ⁇ - ⁇ (or the intensity difference X from the light intensity of the interference light detected at-, and + 0- ⁇ 5 (or the light intensity of the interference light detected at- Based on the intensity difference ⁇ of the light intensity of the interference light detected at ⁇ 0 (or ⁇ ), or the light intensity of the interference light detected at ⁇ + 0 + ⁇ 5 (or ⁇ )
  • the light source 1 and other light sources constituting the optical interferometer 500 are determined based on the intensity difference ⁇ from the light intensity of the interference light detected at the time of ⁇ + 0- ⁇ (or--0 + ⁇ 5).
  • the AGC control is performed so that the output signal gain from the optical interferometer 500 becomes constant in response to this.Specifically, when the output signal from the optical interferometer 500 decreases, the electrical The output signal gain is controlled to be constant by making the signal larger.
  • the light intensity calculation unit 210 refers to a table showing the correspondence between the peak value of the light intensity of the interference light and the optimal phase modulation amplitude that minimizes the random walk value, as described above.
  • the peak value P of the light intensity of the interference light obtained by The table is searched for the optimum phase modulation amplitude corresponding to the amplitude, and this is output to the amplitude 0 generator 202 of the modulation control section 170 as the phase modulation amplitude value 0.
  • the peak value P of the light intensity of the interference light is obtained.
  • the light intensity of the interference light detected when the phase shift is a + 0 + ⁇ 5 (or ⁇ 0 ⁇ ) and the light intensity detected when the phase shift is a ⁇ ⁇ (or ⁇ )
  • the intensity difference X from the light intensity of the interference light, and the light intensity of the interference light detected when - ⁇ (or -0 + ⁇ 5) and the interference light detected when - ⁇ (or-) Based on the intensity difference Z from the light intensity of the phase modulation, the modulation gain error of the phase modulation by the composite signal of the various phase modulations is detected, and the various phase modulations are performed so that the detected modulation gain error becomes zero. Controls the gain of the composite signal.
  • the output of the A / D converter 26 is demodulated at the frequency 1 / by the first demodulator 112, and the demodulation result is subjected to the second demodulation.
  • Demodulation at the frequency 1/2 by the At 2 a detection signal is generated that changes polarity from (+) to (-)-(-) to (+) every / 2.
  • the above-mentioned detection signals are averaged by the first computing unit 1 16 at every time 2 or 4 times, and are summed up by the sum of the skewed signals.
  • the signal (deviation signal of the cellodyne control system) corresponding to the saniyak phase difference ⁇ s required for the operation is extracted.
  • the phase difference of the interference light is generated by the bias modulation signal, and the light intensity value of the interference light detected at this time is used to determine the phase difference of the saniac and the modulation gain. Since the detection error and the change in the light intensity value of the interference light can be detected, the detection signals for serodin control, modulation control, and light intensity calculation can be shared. For this reason, only one A / D converter is required for cellodyne control, modulation control, and detection signal generation for light intensity calculation.
  • the signal reaches 27T for a serodin signal (digital step lamp). Then, the phase shift is reset so that the phase shift of -2 ⁇ is performed. When the signal reaches 2 ⁇ , the phase shift of -2 ⁇ is performed on the synthesized signal of the serodin signal and the phase modulation signal. Reset to perform a reset.
  • the reset is repeatedly performed from the time when the combined signal of the serodin signal and the phase modulation signal reaches 2 ⁇ until the serodin signal reaches 27U.
  • the reset is repeated over a long period of time. Will occur.
  • the reset is performed only for the serodyne signal, so that the reset is repeatedly performed when the input angular velocity to the optical fiber gyro is extremely low. None. Therefore, it is possible to prevent the lock-in phenomenon at a low input angular velocity.
  • the amplitude 0 generator 202, the amplitude ⁇ generator 180, and the amplitude ⁇ generator 180 of the modulation controller 170 are used as the modulation gain control so that the detected modulation gain error is set to zero.
  • the output value of each constant output signal generated by the amplitude generator 208 is adjusted, and the first and second comparators 150 and the third computing unit 144 of the serodyne control unit 152 are used.
  • the second threshold ⁇ The gain of the composite signal of various phase modulations was controlled by adjusting the amount of phase shift by resetting the serodyne signal.
  • the modulation gain control adjusts the amplitude of the generated composite signal of various phase modulations so that the detected modulation gain error becomes zero.
  • FIG. 19 is a schematic configuration diagram of a digital signal processor 100a used in an optical fiber jar opening to which the second embodiment of the present invention is applied.
  • the other configuration of the optical fiber gyroscope of the present embodiment is the same as that of the first embodiment shown in FIG.
  • a digital signal processor 100a used in the present embodiment shown in FIG. 19 is different from the digital signal processor 100a used in the first embodiment shown in FIG. Instead of the modulation control section 170 and the gyro output operation section 240, the serodin control section 140a, the modulation control section 170a and the gyro output operation section 240a, respectively. Is used. Other configurations are the same as those of the digital signal processor 100 shown in FIG.
  • FIG. 20 is a schematic configuration diagram of the serodyne control unit 140a shown in FIG.
  • the same components as those of the serrodyne control unit 140 shown in FIG. 9 are denoted by the same reference numerals.
  • the difference between the serodyne control unit 140a shown in FIG. 20 and the serodyne control unit 140 shown in FIG. 9 is that a reference value storage unit 148 is provided instead of the fourth computing unit 152. That is.
  • the reference value storage unit 148 is used to specify values for specifying the first and second threshold values used in the comparator 150 and the amount of phase shift due to reset in the third computing unit 146. The value of is stored.
  • the generated various phase modulations are performed as modulation gain control so that the detected modulation gain error is set to zero.
  • the amplitude of the synthesized signal itself is adjusted. Therefore, as in the first embodiment, the values for specifying the first and second thresholds used in the comparator 150 and the reset in the third computing unit 144 are used for the modulation gain control. There is no need to adjust the gain for the serodyne signal by adjusting the value to specify the amount of phase shift due to the signal.
  • a value for specifying the first and second threshold values used in the comparator 150 and a value for specifying the phase shift amount due to the reset in the third computing unit 146 are used.
  • a predetermined constant value is stored in the reference value storage unit 148.
  • FIG. 21 is a schematic configuration diagram of the modulation control section 170a shown in FIG. In this figure, the same components as those in the modulation control 140 shown in FIG. 14 are denoted by the same reference numerals.
  • the difference between the modulation control unit 170a shown in FIG. 21 and the modulation control unit 170 shown in FIG. 14 is that the first arithmetic unit 172, the second arithmetic unit 174, and the third arithmetic unit 1 In place of 90, a first computing unit 17 2 a, a second computing unit 17 4 a, and a multiplier 1 78 are provided.
  • the first computing unit 17 2 a integrates the deviation signal (signal corresponding to the modulation gain error specified by the above equation (4)) of the modulation control system sent from the signal processing unit 110. It is an integrator.
  • the second computing unit 174a is an amplifier or a mouth-to-pass filter. Design the gain or fill constant according to the design of the modulation loop control system.
  • the multiplier 178 controls the gain of the combined signals of various phase modulations output from the adder 176 so that the deviation signal of the modulation control system output from the second arithmetic unit 174 becomes zero. Adjust As described above, in the present embodiment, the modulation gain control is performed by adjusting the amplitude of the generated composite signal of various phase modulations so that the detected modulation gain error becomes zero. Therefore, as in the first embodiment, a constant output signal and an amplitude ⁇ generator 18 necessary for performing a phase shift of ⁇ ⁇ output from the generator 102 for the modulation gain control are provided.
  • FIG. 22 is a schematic configuration diagram of the gyro output operation unit 240a shown in FIG. In this figure, the same components as those of the gyro output operation unit 240 shown in FIG. 18 are denoted by the same reference numerals.
  • the second calculator 246a calculates the scale factor value stored in the register 244 and the scale factor correction coefficient sent from the fifth calculator 222 of the light intensity calculator 210. To correct the output of the first computing unit 242. Thereby, the input rotation angular velocity or rotation angle to the optical fiber loop 6 is calculated.
  • the second embodiment of the present invention has been described above.
  • the modulation gain can be controlled so that the detected modulation gain error becomes zero.
  • the multiplier 178 is provided on the output side, and the multiplier 178 adjusts the amplitude of the composite signal of each phase modulation output from the adder 176 so that the detected modulation gain error becomes zero.
  • the modulation gain is controlled.
  • the multiplier 176 is required to perform the arithmetic processing every time width of each step of the composite signal of various phase modulations, that is, every half time. For example, if the optical fiber length L of the optical fiber loop 6 is 100 ⁇ !
  • the light propagation time in the optical fiber loop 6 is about 500 nsec to 10 tsec from the above equation (3).
  • a calculation every ⁇ / 2, that is, a calculation every 250 nsec to 5 sec is required.
  • the amplitude S generator 202 and the amplitude ⁇ generator 1 of the modulation controller 170 are used as the modulation gain control so that the detected modulation gain error is set to zero.
  • the comparator 150 of the cellodyne control unit 152 and the third computing unit 144 The gain of the combined signal of various phase modulations is controlled by adjusting the amount of phase shift by resetting the first and second threshold values ⁇ serodin signal used.
  • the calculation may be performed at a processing speed necessary to correct the modulation gain error.
  • the modulation gain error is caused by changes in temperature, which is a disturbance source, and does not depend on the length of the optical fiber loop. For this reason, usually, if the processing speed of about several milliseconds is calculated, sufficient modulation gain control becomes possible.
  • the speed of the arithmetic processing required for the modulation gain control can be made lower than in the present embodiment.
  • the first embodiment is more advantageous.
  • the three computing units 124 generate a signal (deviation signal of the modulation control system) corresponding to the modulation gain error by the above equation (4).
  • the light intensity of the interference light detected when the phase shift is ++ 0 + ⁇ 5 (or ⁇ ⁇ ) by the second arithmetic unit 122 of the signal processing unit 110 and the -- ⁇ (Or -a +)) Intensity difference X from the light intensity of the stellar light detected during phase shift and a + 0 + 6 (or detected when- ⁇ - ⁇ - ⁇
  • the third arithmetic unit 1 2 4 is obtained by calculating the intensity difference ⁇ between the light intensity of the detected interference light and the light intensity of the interference light detected when ⁇ + 0 ⁇ (or ⁇ 0 + ⁇ 5).
  • the modulation control section 170, 170a modulates the first constant output signal having a value necessary for performing the phase shift of ⁇ . And a second constant output signal having a value necessary for performing a phase shift of ⁇ .
  • a second phase modulation signal in which a pulse having a pulse width of / 2 alternates between positive and negative at a time interval of 2 ⁇ is synthesized with a third constant output signal having a value necessary for performing a phase shift of ⁇ .
  • the bias modulation signal is not limited to the above.
  • the bias modulation signal has a phase difference of the interference light of six values of ⁇ ( ⁇ 0), soil ( ⁇ + 0 + 5), and soil ( ⁇ + 0 ⁇ ), or soil ( ⁇ + 0). , ⁇ ( ⁇ 0 ⁇ ), and ⁇ ( ⁇ 0 + ⁇ ) as long as the phase modulation is performed so as to be repeated at predetermined time intervals and in a predetermined order.
  • a first phase modulation signal consisting of a square wave of frequency l / ⁇ obtained by modulating a first constant output signal having a value necessary to perform a phase shift of ⁇
  • the second one with the value required to perform the phase shift The second phase modulation signal obtained by modulating the constant output signal of (2) and having a pulse width of / 2 that alternates positive and negative at every time interval (2) is used to shift the phase of (a).
  • the phase difference of the interference light becomes ( ⁇ - ⁇ ) ⁇ ( ⁇ ⁇ ⁇ ⁇ ⁇ ) ⁇ (- ⁇ + ⁇ ) ⁇ (- ⁇ - ⁇ - ⁇ ) ⁇ ( ⁇ - ⁇ ) ⁇ ( ⁇ + ⁇ - ⁇ ) ⁇ (--A series of steps in the order, or (a- ⁇ - ⁇ ) ⁇ ( ⁇ ⁇ ) ⁇ (- ⁇ + ⁇ + ⁇ ) ⁇ (- ⁇ - ⁇ ) ⁇ ( ⁇ + ⁇ ) ⁇ (- ⁇ - ⁇ ) ⁇ ( ⁇ + ⁇ ) ⁇ (- ⁇ + 0- ⁇ ) ⁇ (-? ”- ⁇ ⁇ ⁇ ⁇ ⁇ ) or a series of steps,
  • a first phase modulation signal, a second phase modulation signal, and a third constant output signal are generated, and these are added by an adder 206.
  • the modulation generator 200 modulates with the modulation signal of the frequency 1/2 and generates the bias modulation signal, the first phase modulation signal, the second phase modulation signal, and This can be achieved by adjusting the phase (synchronization) relationship between the modulated signals at half the frequency.
  • a change in the light intensity value of the interference light can be detected from the phase difference of the interference light.
  • the loop gain of the serodyne control system can always be kept constant, and this enables stable serodyne control and, consequently, the gyro rotation angular velocity or angle. It is possible to output stably.
  • the modulation gain error can be detected from the phase difference of the interference light, accurate phase modulation can be performed by controlling the modulation so that the detected modulation gain error becomes zero.
  • the scale factor error in the gyro output can be reduced.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Optics & Photonics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Gyroscopes (AREA)

Abstract

L'invention concerne un gyroscope à fibres optiques numérique qui permet d'éliminer des effets d'erreurs de modulation de gain et des changements d'intensité de lumière d'interférence. Un processeur (100) de signaux numériques produit un signal composite contenant divers signaux modulés en phase en combinant un signal de modulation de polarisation et un signal de dynamisation pour supprimer une différence de phase du type Sagnac. Le signal de modulation de polarisation effectue une modulation de phase de sorte que la différence de phase de la lumière d'interférence répète une séquence prédéterminée de six valeurs, c.-à-d. soit ±(η-υ), ±(η+υ+δ) et ±(η+υ-δ), soit ±(η+υ), ±(η-υ-δ) et ±(η-υ+δ), la durée de chaque étape étant de τ/2, τ représentant le temps de propagation de la lumière dans une boucle (6) de fibres optiques. Le signal composite est fourni à un modulateur (5) de phase par un convertisseur (10) N/A.
PCT/JP1999/002163 1998-04-27 1999-04-23 Gyroscope a fibres optiques WO1999056080A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP10/117114 1998-04-27
JP11711498A JPH11304498A (ja) 1998-04-27 1998-04-27 光ファイバジャイロ
JP26305698 1998-09-17
JP10/263056 1998-09-17

Publications (1)

Publication Number Publication Date
WO1999056080A1 true WO1999056080A1 (fr) 1999-11-04

Family

ID=26455288

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP1999/002163 WO1999056080A1 (fr) 1998-04-27 1999-04-23 Gyroscope a fibres optiques

Country Status (1)

Country Link
WO (1) WO1999056080A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1219926A1 (fr) 2000-11-28 2002-07-03 Politecnico di Bari Capteur optique de vitesse de rotation intégré
CN102650526A (zh) * 2012-04-25 2012-08-29 北京航空航天大学 一种基于相位比较调频连续波光纤陀螺的开环检测电路

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63255613A (ja) * 1987-03-27 1988-10-21 リットン・システムズ・インコーポレーテッド 光ファイバ回転センサから出力される光信号を処理する装置
JPH03170869A (ja) * 1989-11-30 1991-07-24 Japan Aviation Electron Ind Ltd デジタルフェイズランプ方式光干渉角速度計
JPH03239911A (ja) * 1990-02-15 1991-10-25 Litton Syst Inc 位相変調、強度復調、および回転検知干渉計の制御のための装置
JPH06129861A (ja) * 1992-10-21 1994-05-13 Tokimec Inc 光ファイバジャイロ
JPH0942976A (ja) * 1995-07-28 1997-02-14 Tokimec Inc 光ファイバジャイロ
JPH0942974A (ja) * 1995-07-28 1997-02-14 Tokimec Inc 光ファイバジャイロ

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63255613A (ja) * 1987-03-27 1988-10-21 リットン・システムズ・インコーポレーテッド 光ファイバ回転センサから出力される光信号を処理する装置
JPH03170869A (ja) * 1989-11-30 1991-07-24 Japan Aviation Electron Ind Ltd デジタルフェイズランプ方式光干渉角速度計
JPH03239911A (ja) * 1990-02-15 1991-10-25 Litton Syst Inc 位相変調、強度復調、および回転検知干渉計の制御のための装置
JPH06129861A (ja) * 1992-10-21 1994-05-13 Tokimec Inc 光ファイバジャイロ
JPH0942976A (ja) * 1995-07-28 1997-02-14 Tokimec Inc 光ファイバジャイロ
JPH0942974A (ja) * 1995-07-28 1997-02-14 Tokimec Inc 光ファイバジャイロ

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1219926A1 (fr) 2000-11-28 2002-07-03 Politecnico di Bari Capteur optique de vitesse de rotation intégré
CN102650526A (zh) * 2012-04-25 2012-08-29 北京航空航天大学 一种基于相位比较调频连续波光纤陀螺的开环检测电路

Similar Documents

Publication Publication Date Title
FR2618545A1 (fr) Gyroscope a fibre optique
EP2827100B1 (fr) Suppression d'erreur de bande morte de gyroscope à fibre optique
JPH03210417A (ja) ファイバー光測定装置、ジャイロメータ、セントラルナビゲーション、及び安定化システム
JP5175129B2 (ja) 閉ループセンサにおける高精度フィードバック制御のためのシステムおよび方法
EP2593749B1 (fr) Modulation de différence de phase d'étalonnage par intermittence pour interféromètre de sagnac
JP2011247891A (ja) 共振器光ファイバージャイロスコープの信号対雑音比を高めるためのシステム及び方法
EP2841877B1 (fr) Dispositif de mesure à fibre optique, gyromètre, centrale de navigation et de stabilisation inertielle
WO2013124584A1 (fr) Dispositif de mesure à fibre optique, gyromètre, centrale de navigation et de stabilisation inertielle
KR101069244B1 (ko) 오차 교정을 이용한 광섬유 자이로스코프의 위상변조 안정화 방법 및 광섬유 자이로스코프
WO1999056080A1 (fr) Gyroscope a fibres optiques
US7006542B2 (en) System and method for stabilizing a laser output frequency
JP3272333B2 (ja) 光ファイバジャイロ
JP2008271028A (ja) 光受信器およびそれに用いる光干渉計の動作点安定化方法
JP4109757B2 (ja) 光ファイバジャイロ
JPH11108669A (ja) 光ファイバジャイロ
JP2000146597A (ja) 光ファイバジャイロ
JP2021081334A (ja) 光ファイバジャイロ並びにその制御方法及び制御装置
JPH11257971A (ja) 光ファイバジャイロ
JPH11304498A (ja) 光ファイバジャイロ
JP3245796B2 (ja) 光ファイバジャイロ
JPH10132578A (ja) 光ファイバジャイロ
JPH04369421A (ja) 光ファイバジャイロ
JP2003004452A (ja) 光干渉角速度計
JP2969212B2 (ja) 光干渉角速度計
JPH11351882A (ja) 光干渉角速度計

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): NO US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase