CN108132062A - Fiber-optic gyroscope light path power detecting method and device based on four frequency dividing four states modulation - Google Patents
Fiber-optic gyroscope light path power detecting method and device based on four frequency dividing four states modulation Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C25/00—Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass
- G01C25/005—Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass initial alignment, calibration or starting-up of inertial devices
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
- G01J9/02—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
- G01J2001/4242—Modulated light, e.g. for synchronizing source and detector circuit
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
- G01J9/02—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods
- G01J2009/0226—Fibres
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
- G01J9/02—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods
- G01J2009/0249—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods with modulation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
- G01J9/02—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods
- G01J2009/0276—Stellar interferometer, e.g. Sagnac
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Abstract
The invention discloses a kind of fiber-optic gyroscope light path power detecting methods and device based on four frequency dividing four states modulation.Wherein, this method comprises the following steps：Using four four state modulated signals of frequency dividing to the light wave clockwise in fiber optic loop and Light Modulation counterclockwise；Light path power is obtained according to the intensity of interference signal after modulation.The present invention does not generate interference to signal of fiber optical gyroscope access, does not need to additionally increase the fiber-optic gyroscope light path power detecting method of device, so as in the case where not influencing fiber optic gyroscope performance, reduce the complexity of system, reduce the cost and volume of system.
Description
Technical field
The invention belongs to fiber-optics gyroscope field more particularly to a kind of optical fibre gyro light based on four frequency dividing four states modulation
Road power detecting method and device.
Background technology
Optical fibre gyro is a kind of angular-rate sensor based on Sagnac effects, have high-precision, it is all solid state, it is highly reliable etc.
Feature is widely used in the satel-lite at present.Critical component of the optical fibre gyro as measuring system of satellite attitude,
Its performance directly determines the control accuracy of satellite, and the failure of optical fibre gyro results even in the failure of satellite task.Light source
As optical fibre gyro core optical element, performance deterioration may occur under the environmental activities such as space radiation and even fail, and then
Optical fiber gyroscope precision is caused to deteriorate and fail.In order to ensure control accuracy of the satellite within phase projected life, satellite optical fiber top
Spiral shell usually sets backup light source, and performance of handoffs normally backs up light source in the performance deterioration of main light source.It completes effectively to cut
It changes, on condition that the reason of completing the interpretation to optical fibre gyro failure first, determining fiber optic gyroscope performance deterioration is light source failure, and
It is to judge that light source failure is most direct, effective approach by being monitored to source device output optical power.Due to signal of fiber optical gyroscope
The particularity of detection circuit scheme, at present the common luminous power detection method of optical fibre gyro have following two：
First method is one detection branch of parallel connection on the normal measure loop of optical fibre gyro photodetector rear end,
Pass through operational amplifier and A/D converter indirect detection luminous power.The shortcomings that this method is：(1) detection branch is directly connected to
On the photodetector in normal circuit, interference can be brought to normal measure loop, so as to influence the working performance of product；
(2) low-pass filter circuit and A/D converter are increased, improves product cost, and increase circuit size so that circuit is small-sized
Change is difficult to realize.
Second method is the 2X2 couplers bear end welding photodetector after optical fibre gyro light source, and is put with operation
Big device, low-pass filter circuit are connected with A/D converter, the Direct-detection Optical power from light path.The shortcomings that this method is：(1)
Level-one photodetector is increased, so as to increase the complexity of light path part design, reduces the reliability of product, and carry
High cost；(2) operational amplifier, low-pass filter circuit and A/D converter are increased, improves product cost, and increase
Circuit size so that circuit miniaturization is difficult to realize.
To sum up, existing luminous power detection method is all by increasing additional device from original signal of fiber optical gyroscope access
Middle extraction signal is detected, and on the one hand these methods can influence fiber optic gyroscope performance, on the other hand increase the complexity of system
Degree, so as to reduce the reliability of system, increases the cost and volume of system, is not particularly suited for performance, reliability, cost
Require higher space in optical fibre gyro with volume.
Invention content
Present invention solves the technical problem that it is：Overcome the deficiencies in the prior art, it is proposed that one kind is based on four four state tune of frequency dividing
The fiber-optic gyroscope light path power detecting method and device of system do not generate interference to signal of fiber optical gyroscope access, do not need to additionally increase
Add the fiber-optic gyroscope light path power detecting method of device, so as in the case where not influencing fiber optic gyroscope performance, reduce system
Complexity, reduce the cost and volume of system.
The object of the invention is achieved by the following technical programs：On the one hand, the present invention proposes a kind of based on four frequency dividings
The fiber-optic gyroscope light path power detecting method of four states modulation, the described method comprises the following steps：Use four frequency dividing four states modulation letters
Number to the light wave clockwise in fiber optic loop and Light Modulation counterclockwise；Light path work(is obtained according to the intensity of interference signal after modulation
Rate.
Further, it is above-mentioned based on four frequency dividing four states modulation fiber-optic gyroscope light path power detecting method in, further include with
Lower step：Optical fibre gyro speed error is obtained according to the intensity of interference signal after modulation.
Further, in the above-mentioned fiber-optic gyroscope light path power detecting method based on four frequency dividing four states modulation, four points are used
Frequently four state modulated signals include the light wave clockwise in fiber optic loop and Light Modulation counterclockwise：Use four frequency dividing four states modulation letters
Number to the light wave clockwise in each period in fiber optic loop and Light Modulation counterclockwise.
Further, in the above-mentioned fiber-optic gyroscope light path power detecting method based on four frequency dividing four states modulation, four points are used
Frequently four state modulated signals include the following steps the light wave clockwise in each period in fiber optic loop and Light Modulation counterclockwise：
Step 1：The phase-modulation of π/4 is carried out to the light wave clockwise in fiber optic loop, while π/4 are carried out to the light wave counterclockwise in fiber optic loop
Modulation, duration are a fiber optic loop transition time, and output signal is strong after extracting light wave clockwise and optical interference counterclockwise
Degree, is denoted as PA；Step 2：The phase-modulation of 3 π/4 is carried out, while to counterclockwise in fiber optic loop to the light wave clockwise in fiber optic loop
Light wave carries out π/4 and modulates, and the duration is a fiber optic loop transition time, after extracting light wave clockwise and optical interference counterclockwise
Output signal strength is denoted as PB；Step 3：The phase-modulation of 3 π/4 is carried out, while to fiber optic loop to the light wave clockwise in fiber optic loop
Interior light wave counterclockwise carries out 3 π/4 and modulates, and the duration is a fiber optic loop transition time, extracts light wave clockwise and inverse time
Output signal strength after needle optical interference, is denoted as PC；Step 4：To the phase-modulation of the light wave progress-π clockwise in fiber optic loop/4,
It carries out 3 π/4 to the light wave counterclockwise in fiber optic loop simultaneously to modulate, the duration is a fiber optic loop transition time, extracts up time
Output signal strength after needle light wave and optical interference counterclockwise, is denoted as PD；Step 5：Light wave clockwise in fiber optic loop is carried out-
The phase-modulation of π/4, while to the modulation of the light wave progress-π counterclockwise in fiber optic loop/4, when the duration gets over for a fiber optic loop
Between, output signal strength after light wave clockwise and optical interference counterclockwise is extracted, is denoted as PE；Step 6：To the up time in fiber optic loop
Needle light wave carries out the phase-modulation of -3 π/4, while to the modulation of the light wave progress-π counterclockwise in fiber optic loop/4, the duration is one
The fiber optic loop transition time extracts output signal strength after light wave clockwise and optical interference counterclockwise, is denoted as PF；Step 7：To light
Light wave clockwise in fine ring carries out the phase-modulation of -3 π/4, while the modulation of -3 π/4 is carried out to the light wave counterclockwise in fiber optic loop,
Duration is a fiber optic loop transition time, extracts output signal strength after light wave clockwise and optical interference counterclockwise, is remembered
For PG；Step 8：Carry out the phase-modulation of π/4 to the light wave clockwise in fiber optic loop, at the same to the light wave counterclockwise in fiber optic loop into
Row -3 π/4 are modulated, and the duration is a fiber optic loop transition time, is exported after extracting light wave clockwise and optical interference counterclockwise
Signal strength is denoted as PH。
Further, in the above-mentioned fiber-optic gyroscope light path power detecting method based on four frequency dividing four states modulation, according to modulation
The intensity of interference signal obtains light path power and includes afterwards：According to signal strength PA, signal strength PE, signal strength PDIt is strong with signal
Spend PHObtain light path power.
Further, in the above-mentioned fiber-optic gyroscope light path power detecting method based on four frequency dividing four states modulation, light path power
Calculation formula be：|ΔP2|=| PA+PE–PD–PH|=2P0, wherein, P0For light path power.
Further, in the above-mentioned fiber-optic gyroscope light path power detecting method based on four frequency dividing four states modulation, according to modulation
The intensity of interference signal obtains optical fibre gyro speed error and includes afterwards：According to signal strength PB, signal strength PFIt is obtained with light path power
To optical fibre gyro speed error.
Further, in the above-mentioned fiber-optic gyroscope light path power detecting method based on four frequency dividing four states modulation, optical fibre gyro
The calculation formula of speed error is：|ΔP1|=| PB-PF|=| 2P0s inΔφs|, wherein, P0For light path power.
On the other hand, the invention also provides a kind of fiber-optic gyroscope light path power detection dresses based on four frequency dividing four states modulation
It puts, which includes：Light Modulation module, for using four frequency dividings, four state modulated signal to the light wave clockwise in fiber optic loop and
Light Modulation counterclockwise；Light path power computation module, for obtaining light path power according to the intensity of interference signal after modulation.
Further, it in the above-mentioned fiber-optic gyroscope light path power detection device based on four frequency dividing four states modulation, further includes：Light
Fine gyroscope speed error calculating module, for obtaining optical fibre gyro speed error according to the intensity of interference signal after modulation.
The present invention has the advantages that compared with prior art：
The present invention is not causing optical fibre gyro original signal access by designing four special four state modulation algorithms of frequency dividing
Under the premise of interfering and not increasing additional devices so that in optical fibre gyro output interference signal other than comprising angular speed error,
The signal of reflection light source output power size is also included, light extraction work(can be demodulated by acquiring particular state signal in modulation period
Rate information.Without additionally increasing the fiber-optic gyroscope light path power detecting method of device, fiber optic gyroscope performance is not being influenced
In the case of, the complexity of system is reduced, reduces the cost and volume of system.
Description of the drawings
By reading the detailed description of hereafter preferred embodiment, it is various other the advantages of and benefit it is common for this field
Technical staff will become clear.Attached drawing is only used for showing the purpose of preferred embodiment, and is not considered as to the present invention
Limitation.And throughout the drawings, the same reference numbers will be used to refer to the same parts.In the accompanying drawings：
Fig. 1 is the fiber-optic gyroscope light path power detecting method provided in an embodiment of the present invention based on four frequency dividing four states modulation
Flow chart；
Fig. 2 is fiber-optic gyroscope light path basic principle block diagram provided in an embodiment of the present invention；
Fig. 3 is the schematic diagram of ± pi/2 square-wave frequency modulation scheme waveform provided in an embodiment of the present invention；
Fig. 4 is the schematic diagram that ± pi/2 square-wave frequency modulation provided in an embodiment of the present invention obtains angular speed principle；
Fig. 5 is the schematic diagram of four frequency dividing provided in an embodiment of the present invention, four state modulation scheme waveforms；
Fig. 6 is the schematic diagram that four frequency dividing provided in an embodiment of the present invention, four states modulation obtains luminous power and angular speed principle；
Fig. 7 is the schematic diagram of luminous power detection method output and input optical power relationship provided in an embodiment of the present invention.
Specific embodiment
The exemplary embodiment of the disclosure is more fully described below with reference to accompanying drawings.Although the disclosure is shown in attached drawing
Exemplary embodiment, it being understood, however, that may be realized in various forms the disclosure without should be by embodiments set forth here
It is limited.On the contrary, these embodiments are provided to facilitate a more thoroughly understanding of the present invention, and can be by the scope of the present disclosure
Completely it is communicated to those skilled in the art.It should be noted that in the absence of conflict, embodiment in the present invention and
Feature in embodiment can be combined with each other.The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.
Embodiment of the method：
Referring to Fig. 1, Fig. 1 is the fiber-optic gyroscope light path power inspection provided in an embodiment of the present invention based on four frequency dividing four states modulation
The flow chart of survey method.As shown in the figure, an embodiment of the present invention provides a kind of optical fibre gyro light based on four frequency dividing four states modulation
Road power detecting method, this method include the following steps：
Using four four state modulated signals of frequency dividing to the light wave clockwise in fiber optic loop and Light Modulation counterclockwise；
Light path power is obtained according to the intensity of interference signal after modulation；
Optical fibre gyro speed error is obtained according to the intensity of interference signal after modulation.
The light wave clockwise in fiber optic loop and Light Modulation counterclockwise are included using four four state modulated signals of frequency dividing：It uses
Four four state modulated signals of frequency dividing are to the light wave clockwise in each period in fiber optic loop and Light Modulation counterclockwise.
Further, using four four state modulated signals of frequency dividing to the light wave clockwise in each period in fiber optic loop and inverse
Hour hands Light Modulation includes the following steps：
Step 1：The phase-modulation of π/4 is carried out, while to the light counterclockwise in fiber optic loop to the light wave clockwise in fiber optic loop
Wave carries out the modulation of π/4, and the duration is a fiber optic loop transition time, extracts defeated after light wave clockwise and optical interference counterclockwise
Go out signal strength, be denoted as PA；
Step 2：The phase-modulation of 3 π/4 is carried out, while to the light counterclockwise in fiber optic loop to the light wave clockwise in fiber optic loop
Wave carries out the modulation of π/4, and the duration is a fiber optic loop transition time, extracts defeated after light wave clockwise and optical interference counterclockwise
Go out signal strength, be denoted as PB；
Step 3：The phase-modulation of 3 π/4 is carried out, while to the light counterclockwise in fiber optic loop to the light wave clockwise in fiber optic loop
Wave carries out 3 π/4 and modulates, and the duration is a fiber optic loop transition time, after extracting light wave clockwise and optical interference counterclockwise
Output signal strength is denoted as PC；
Step 4：To the phase-modulation of the light wave progress-π clockwise in fiber optic loop/4, while to the light counterclockwise in fiber optic loop
Wave carries out 3 π/4 and modulates, and the duration is a fiber optic loop transition time, after extracting light wave clockwise and optical interference counterclockwise
Output signal strength is denoted as PD；
Step 5：To the phase-modulation of the light wave progress-π clockwise in fiber optic loop/4, while to the light counterclockwise in fiber optic loop
Wave progress-π/4 are modulated, and the duration is a fiber optic loop transition time, after extracting light wave clockwise and optical interference counterclockwise
Output signal strength is denoted as PE；
Step 6：The phase-modulation of -3 π/4 is carried out, while to counterclockwise in fiber optic loop to the light wave clockwise in fiber optic loop
Light wave progress-π/4 are modulated, and the duration is a fiber optic loop transition time, extracts light wave clockwise and optical interference counterclockwise
Output signal strength afterwards is denoted as PF；
Step 7：The phase-modulation of -3 π/4 is carried out, while to counterclockwise in fiber optic loop to the light wave clockwise in fiber optic loop
Light wave carries out -3 π/4 and modulates, and the duration is a fiber optic loop transition time, extracts light wave clockwise and optical interference counterclockwise
Output signal strength afterwards is denoted as PG；
Step 8：The phase-modulation of π/4 is carried out, while to the light counterclockwise in fiber optic loop to the light wave clockwise in fiber optic loop
Wave carries out -3 π/4 and modulates, and the duration is a fiber optic loop transition time, after extracting light wave clockwise and optical interference counterclockwise
Output signal strength is denoted as PH。
It should be noted that step 1 is realized successively sequentially in time to step 8, it is, continuing in step 1
It is carved at the beginning of the finish time of time i.e. step 2 duration, and so on, until step 8, step 1 is total to step 8
Duration is a cycle altogether.
Light path power is obtained according to the intensity of interference signal after modulation to include：According to signal strength PA, signal strength PE, letter
Number intensity PDWith signal strength PHObtain light path power.Further, the calculation formula of light path power is：|ΔP2|=| PA+PE–
PD–PH|=2P0, wherein, P0For light path power.
Optical fibre gyro speed error is obtained according to the intensity of interference signal after modulation to include：According to signal strength PB, signal
Intensity PFOptical fibre gyro speed error is obtained with light path power.Further, the calculation formula of optical fibre gyro speed error is：|
ΔP1|=| PB-PF|=| 2P0s inΔφs|, wherein, P0For light path power.
Specifically, optical fibre gyro is the angular rate measurement device based on Sagnac effects, light path basic principle such as Fig. 2 institutes
Show.The light that light source is sent out enters electrooptic modulator by 2 × 2 couplers, and light is divided into two beams in electrooptic modulator, respectively edge
Fiber optic loop transmits a circle and returns electrooptic modulator clockwise and anticlockwise, and two-beam wave closes beam at electrooptic modulator end, generates
The phase of interference signal, wherein interference signal is the difference of phase that two-beam wave respectively contains, and interference signal enters through coupler
Detector is detected.Electrooptic modulator can also carry out light wave suitable, counterclockwise while carrying out light wave beam splitting and closing beam
Phase-modulation.Detector end interference signal luminous power P meets following relationship：P=P0(1+cos(Δφs+ΦDM)), wherein P0For
Light source output power, Δ φsFor the Sagnac phase differences as caused by angular speed, ΦDMIt is poor for phase modulation.Optical fibre gyro is more at present
Using complete-digital closed-loop scheme, the detection of small-signal is realized based on modulation-demodulation technique, in order to obtain peak response one
As phase modulation difference is set as ± pi/2.Modulation waveform is as shown in figure 3, Φ in figureDM-CWFor to light wave modulation phase clockwise
Position, modulation waveform frequency is optical fiber gyroscope eigenfrequency, i.e., using 2 times of optical fibre gyro transition time τ as the period, with ± π/4 for width
The square wave of value；ΦDM-CCWFor the phase modulation to square wave counterclockwise, modulation waveform and clockwise modulation waveform cycle phase
Together, amplitude is opposite.To the difference that the phase modulation difference of interference signal is Light Modulation phase suitable, counterclockwise, i.e. ΦDM=ΦDM-CW-
ΦDM-CCW, modulation waveform and detector output waveform it is as shown in Figure 3.Left side reference axis top is more than optical fibre gyro in Fig. 3
String interference signal, lower part are phase modulation difference waveform, and modulated rear detector output interference signal waveform is shown on the right side of Fig. 4.
Since ± pi/2 modulated two transition time corresponding luminous power is respectively PA=P0*(1+cos(Δφs+ pi/2)), PB=
P0*(1+cos(ΔφsPi/2)), after demodulation | Δ P |=| PA-PB|=| 2P0s inΔφs|, therefore in normal closed loop work shape
Under state, P as shown in Figure 5A-PBThe angular speed error amount of optical fibre gyro is corresponded to, is the angular speed pair of optical fibre gyro after integration
It should be worth.But since square-wave frequency modulation is subtracted each other by adjacent periods, a demodulation value only can be obtained, the change of demodulation value, which cannot be distinguished, is
Caused by changing still luminous power change due to rotating speed, luminous power detection can not be carried out.This patent devises four points thus
Frequently four state modulation scheme, modulation scheme waveform are as shown in Figure 5.Light Modulation phase Φ clockwiseDM-CWPeriod is 8 τ, is divided into four
A state, each state duration are 2 τ, and corresponding phase modulation is followed successively by π/4,3 π/4,-π/4, -3 π/4.Light counterclockwise
Wave phase modulation ΦDM-CCWOne τ of Light Modulation phase delay more clockwise, after optical interference suitable, counterclockwise, obtained modulation
Waveform and corresponding detector output interference signal waveform are as shown in Figure 6.Left side reference axis top half is optical fibre gyro in figure
Cosine interference signal, lower half portion are four four state modulation waveforms of frequency dividing, right in corresponding optical fibre gyro interference signal output such as figure
Shown in side.It can be seen from the figure that after using four frequency dividing four states modulation, in an internal modulation modulation period signal to the suitable, inverse time
The phase modulation of needle light wave is followed successively by there are 8 combinations of states：(1) to the phase modulation of light wave π clockwise/4, to light counterclockwise
The phase modulation of wave π/4, the total phase of interference signal are 0；(2) to the phase modulation of 3 π of light wave clockwise/4, light wave π counterclockwise/4 are adjusted
Phase processed, the total phase of interference signal are pi/2；(3) to the phase modulation of 3 π of light wave clockwise/4, to the modulation phase of 3 π of light wave counterclockwise/4
Position, the total phase of interference signal are 0；(4) it to the phase modulation of light wave-π clockwise/4, to the phase modulation of 3 π of light wave counterclockwise/4, does
The total phase of signal is related to as-π；(5) to the phase modulation of light wave-π clockwise/4, to the phase modulation of light wave-π counterclockwise/4, interference letter
Number total phase is 0；(6) to the phase modulation of -3 π of light wave clockwise/4, to the phase modulation of light wave-π counterclockwise/4, interference signal is total
Phase is-pi/2；(7) to the phase modulation of -3 π of light wave clockwise/4, to the phase modulation of -3 π of light wave counterclockwise/4, interference signal is total
Phase is 0；(8) to the phase modulation of light wave π clockwise/4, to the phase modulation of -3 π of light wave counterclockwise/4, the total phase of interference signal is
π；Obtained interference signal is followed successively by PA~PH.According to optical fibre gyro basic principle it is found that passing through calculation formula | Δ P1|=| PB-
PF|=| 2P0s inΔφs| the angular speed error of optical fibre gyro can be obtained, and passes through calculation formula | Δ P2|=| PA+PE–
PD–PH|=2P0Light source output power can be obtained.Therefore, it after using four frequency dividing four states modulation, does not need to increase additional device
And signal path is generated to interfere to export in interference signal from detector and extract optical power value.The side proposed using this patent
Method extracts optical power value, has obtained the relationship of output digital quantity and input optical power as shown in fig. 7, it can be seen from the figure that defeated
There are preferable linear relationships between output and input optical power, it was demonstrated that the validity of institute's extracting method.
The present embodiment is not being made optical fibre gyro original signal access by designing four special four state modulation algorithms of frequency dividing
Under the premise of interference and not increasing additional devices so that in addition to including angular speed error in optical fibre gyro output interference signal
Outside, the signal of reflection light source output power size is also included, can be demodulated by acquiring particular state signal in modulation period
Op-tical power information.Without additionally increasing the fiber-optic gyroscope light path power detecting method of device, optical fibre gyro is not being influenced
In the case of performance, the complexity of system is reduced, reduces the cost and volume of system.
Device embodiment：
The present embodiment also proposed a kind of fiber-optic gyroscope light path power detection device based on four frequency dividing four states modulation, the dress
It puts including Light Modulation module and light path power computation module.Wherein, Light Modulation module, for four frequency dividings, four state to be used to modulate
Signal is to the light wave clockwise in fiber optic loop and Light Modulation counterclockwise；Light path power computation module, for being done according to after modulation
The intensity for relating to signal obtains light path power.
In above-described embodiment, the fiber-optic gyroscope light path power detection device based on four frequency dividing four states modulation further includes：Optical fiber
Gyroscope speed error calculating module, for obtaining optical fibre gyro speed error according to the intensity of interference signal after modulation.
The present embodiment by Light Modulation module, light path power computation module and optical fibre gyro speed error computing module,
Under the premise of not interfered to optical fibre gyro original signal access and not increasing additional devices so that optical fibre gyro output is dry
It relates in signal other than comprising angular speed error, also includes the signal of reflection light source output power size, by acquiring modulation week
Particular state signal can demodulate op-tical power information in phase.Without additionally increasing the fiber-optic gyroscope light path power of device
Detection method in the case where not influencing fiber optic gyroscope performance, reduces the complexity of system, reduces the cost and body of system
Product.
Embodiment described above is the present invention more preferably specific embodiment, and those skilled in the art is in this hair
The usual variations and alternatives carried out in the range of bright technical solution should all include within the scope of the present invention.
Claims (10)
- A kind of 1. fiber-optic gyroscope light path power detecting method based on four frequency dividing four states modulation, which is characterized in that the method packet Include following steps：Using four four state modulated signals of frequency dividing to the light wave clockwise in fiber optic loop and Light Modulation counterclockwise；Light path power is obtained according to the intensity of interference signal after modulation.
- 2. the fiber-optic gyroscope light path power detecting method according to claim 1 based on four frequency dividing four states modulation, feature It is, it is further comprising the steps of：Optical fibre gyro speed error is obtained according to the intensity of interference signal after modulation.
- 3. the fiber-optic gyroscope light path power detecting method according to claim 1 or 2 based on four frequency dividing four states modulation, special Sign is：The light wave clockwise in fiber optic loop and Light Modulation counterclockwise are included using four four state modulated signals of frequency dividing：It uses Four four state modulated signals of frequency dividing are to the light wave clockwise in each period in fiber optic loop and Light Modulation counterclockwise.
- 4. the fiber-optic gyroscope light path power detecting method according to claim 3 based on four frequency dividing four states modulation, feature It is：Using four four state modulated signals of frequency dividing to the light wave clockwise in each period in fiber optic loop and Light Modulation counterclockwise Include the following steps：Step 1：Carry out the phase-modulation of π/4 to the light wave clockwise in fiber optic loop, at the same to the light wave counterclockwise in fiber optic loop into Row π/4 are modulated, and the duration is a fiber optic loop transition time, and letter is exported after extracting light wave clockwise and optical interference counterclockwise Number intensity, is denoted as PA；Step 2：Carry out the phase-modulation of 3 π/4 to the light wave clockwise in fiber optic loop, at the same to the light wave counterclockwise in fiber optic loop into Row π/4 are modulated, and the duration is a fiber optic loop transition time, and letter is exported after extracting light wave clockwise and optical interference counterclockwise Number intensity, is denoted as PB；Step 3：Carry out the phase-modulation of 3 π/4 to the light wave clockwise in fiber optic loop, at the same to the light wave counterclockwise in fiber optic loop into 3 π of row/4 are modulated, and the duration is a fiber optic loop transition time, is exported after extracting light wave clockwise and optical interference counterclockwise Signal strength is denoted as PC；Step 4：To the phase-modulation of the light wave progress-π clockwise in fiber optic loop/4, at the same to the light wave counterclockwise in fiber optic loop into 3 π of row/4 are modulated, and the duration is a fiber optic loop transition time, is exported after extracting light wave clockwise and optical interference counterclockwise Signal strength is denoted as PD；Step 5：To the phase-modulation of the light wave progress-π clockwise in fiber optic loop/4, at the same to the light wave counterclockwise in fiber optic loop into Row-π/4 are modulated, and the duration is a fiber optic loop transition time, is exported after extracting light wave clockwise and optical interference counterclockwise Signal strength is denoted as PE；Step 6：The phase-modulation of -3 π/4 is carried out, while to the light wave counterclockwise in fiber optic loop to the light wave clockwise in fiber optic loop The modulation of progress-π/4, duration are a fiber optic loop transition time, are extracted defeated after light wave clockwise and optical interference counterclockwise Go out signal strength, be denoted as PF；Step 7：The phase-modulation of -3 π/4 is carried out, while to the light wave counterclockwise in fiber optic loop to the light wave clockwise in fiber optic loop The modulation of -3 π/4 is carried out, the duration is a fiber optic loop transition time, is extracted defeated after light wave clockwise and optical interference counterclockwise Go out signal strength, be denoted as PG；Step 8：Carry out the phase-modulation of π/4 to the light wave clockwise in fiber optic loop, at the same to the light wave counterclockwise in fiber optic loop into Row -3 π/4 are modulated, and the duration is a fiber optic loop transition time, is exported after extracting light wave clockwise and optical interference counterclockwise Signal strength is denoted as PH。
- 5. the fiber-optic gyroscope light path power detecting method according to claim 4 based on four frequency dividing four states modulation, feature It is：Light path power is obtained according to the intensity of interference signal after modulation to include：According to signal strength PA, signal strength PE, signal it is strong Spend PDWith signal strength PHObtain light path power.
- 6. the fiber-optic gyroscope light path power detecting method according to claim 5 based on four frequency dividing four states modulation, feature It is：The calculation formula of light path power is：|ΔP2|=| PA+PE–PD–PH|=2P0, wherein, P0For light path power.
- 7. the fiber-optic gyroscope light path power detecting method according to claim 6 based on four frequency dividing four states modulation, feature It is：Optical fibre gyro speed error is obtained according to the intensity of interference signal after modulation to include：According to signal strength PB, signal strength PFOptical fibre gyro speed error is obtained with light path power.
- 8. the fiber-optic gyroscope light path power detecting method according to claim 7 based on four frequency dividing four states modulation, feature It is：The calculation formula of optical fibre gyro speed error is：|ΔP1|=| PB-PF|=| 2P0sinΔφs|, wherein, P0For light path power.
- 9. a kind of fiber-optic gyroscope light path power detection device based on four frequency dividing four states modulation, it is characterised in that including：Light Modulation module, for using four frequency dividings, four state modulated signal to the light wave clockwise in fiber optic loop and light wave counterclockwise Modulation；Light path power computation module, for obtaining light path power according to the intensity of interference signal after modulation.
- 10. the fiber-optic gyroscope light path power detection device according to claim 9 based on four frequency dividing four states modulation, feature It is, further includes：Optical fibre gyro speed error computing module, for obtaining optical fibre gyro according to the intensity of interference signal after modulation Speed error.
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