CN106767905A - Separate double detector type optical fibre gyro light source and electronic noise correlation calculations method - Google Patents

Abstract

Double detector type optical fibre gyro light source and electronic noise correlation calculations method are separated the invention discloses one kind.Optical fibre gyro dead end not incoming fiber optic time delay ring, calculates the data signal that signalling channel analog-digital converter and light source channel modulus converter are exported the value for obtaining and not accessing lower two digital signal variances and Normalized Cross Correlation Function in zero moment；The dead end incoming fiber optic time delay ring of optical fibre gyro, calculates the data signal that signalling channel analog-digital converter and light source channel modulus converter are exported the value for obtaining and accessing lower two digital signal variances and Normalized Cross Correlation Function in zero moment again；Computing obtains light source and electronic noise cross-correlation function in zero moment ratio, and then can respectively try to achieve source noise and the respective Normalized Cross Correlation Function of electronic noise.The present invention can in the sense channel of accurate evaluation two source noise correlation it is strong and weak, without being disturbed by electronic noise, thus accurate evaluation double detector type optical fibre gyro by subtractive method to the inhibitory action of source noise.

Description

Separate double detector type optical fibre gyro light source and electronic noise correlation calculations method

Technical field

The present invention relates to signal correlation detection technique, a kind of more particularly to separation double detector type optical fibre gyro Light source and electronic noise correlation calculations method.

Background technology

Optical fibre gyro light source uses wide spectrum light source, and random beat frequency occurs between different frequency component in light source light extraction generates Relative intensity noise.In order to drop relative intensity noise of light source of fiber-optic gyroscope frequently with double detector type optical fibre gyro.Double detector Type optical fibre gyro is to increased fiber delay time ring and detector in the dead end of optical fibre gyro minimum reciprocal system, by two detectors Signal subtraction reduction light source relative intensity noise, its effect depends on source noise correlation in two paths of signals.Document《Pre- estimate Relative Intensity Noise Subtraction Performance of FOG by Using Signal Cross-Correlation》The source noise normalization in two paths of signals is mentioned in (Zhang Yonggang) related When coefficient is less than 0.5, subtractive method can not only reduce noise, can amplify source noise on the contrary.Measure two Air conduct measurements Signal correlation passes through inhibitory action of the subtractive method to light source relative intensity noise for evaluating double detector type optical fibre gyro, with And the main source of two sense channel sampled signal correlations is source noise or electricity in the different design of FOG schemes of determination Sub- noise is significant.

Actual conditions be in two sense channel detection signals in addition to source noise, further comprises electronic noise.Source noise With the noise that electronic noise together constitutes detection signal, source noise correlation by electronic noise correlation due to being disturbed nothing Method independent measurement, limits the desired value accuracy to double detector type optical fibre gyro noise reduction, also limit double detector The further optimization design of type optical fibre gyro.

The content of the invention

Electronic noise interference cannot be excluded for traditional double probe type optical fibre gyro, so as to source noise correlation list The present situation for solely measuring, the present invention proposes a kind of separation double detector type optical fibre gyro light source and electronic noise correlation calculations side Method can respectively obtain source noise Normalized Cross Correlation Function and electronic noise Normalized Cross Correlation Function.So that source noise The measurement of Normalized Cross Correlation Function is not disturbed by electronic noise, so that accurate evaluation double detector type optical fibre gyro is by subtracting each other Inhibitory action of the method to source noise.

The technical solution adopted by the present invention：

Step one, passed through successively in the dead end (i.e. the light signal output end of fiber coupler) of double detector type optical fibre gyro Digital signal processor, the light source channels connection of fiber coupler are connected to after ray detector, light source channel modulus converter Ray detector, now not incoming fiber optic time delay ring, respectively by signalling channel analog-digital converter and light source channels analog-to-digital conversion Device exports respective data signal, and two logical S roads moulds under obtaining non-incoming fiber optic time delay ring are calculated in digital signal processor Variance Var [the n of number converter output digit signals_A(t)] and Var [n_B(t)] and Normalized Cross Correlation Function in zero moment ValueVar[n_A(t)] represent signal sensor data signal variance, Var [n_B(t)] represent ray detector Data signal variance；

Step 2, double detector type optical fibre gyro dead end successively through fiber delay time ring, ray detector, light source channels Digital signal processor is connected to after analog-digital converter, passes through signalling channel analog-digital converter and light source channels modulus respectively again Converter exports respective data signal, and two passage moulds under obtaining incoming fiber optic time delay ring are calculated in digital signal processor Variance Var [the n of number converter output digit signals_A' (t)] and Var [n_B' (t)] and Normalized Cross Correlation Function in zero moment Value

Step 3, closing light source power supply, now the signal sensor output electric signal of signalling channel is only comprising electronic noise And do not include source noise, the data signal n exported by signalling channel analog-digital converter_e(t), in digital signal processor Calculate the variance Var [n that signalling channel analog-digital converter output digit signals under light source are closed in acquisition_e(t)], Var [n_e(t)] it is real Matter is electronic noise variance；

Step 4, the variance with above-mentioned gained and Normalized Cross Correlation Function value carry out computing, obtain source noise mutual Function is closed in zero moment ratio R_optAnd electronic noise cross-correlation function is in zero moment ratio R (0)_ele(0), both ratio k=R_opt (0)/R_ele(0)；

Step 5, the variance with above-mentioned gained, Normalized Cross Correlation Function value and ratio k carry out computing, respectively obtain light Source noise Normalized Cross Correlation Function ρ_oWith electronic noise Normalized Cross Correlation Function ρ_e, it is each as source noise and electronic noise From correlation.

Source noise and electronic noise correlation refer to electronic noise and source noise to two sense channel sampled signal phases The ratio of closing property contribution.

Normalized Cross Correlation Function refer to gather the moment two channel modulus converter output digit signals between it is mutual It is related.

The n_A(t)、n_A′(t)、n_e(t)、n_B(t) and n_B' (t) represents the noise of respective channel output signal.Because optical fiber Gyro system is in stable state, and noise shows as the AC compounent on direct current signal, the output signal of sense channel is carried out Blocking filtering obtains noise signal.

Described double detector type optical fibre gyro is visited by light source, fiber coupler, Y waveguide, optical fiber sensing ring, signal Survey in the optical fibre gyro minimum reciprocal system-based of device, signalling channel analog-digital converter and digital signal processor composition, in light Fine coupler dead end connection fiber delay time ring, ray detector and light source channel modulus converter are formed.

The fiber coupler dead end is that fiber coupler does not make in double detector type optical fibre gyro minimum reciprocal system Port, is not connected during fiber coupler dead end first step collection data signal with fiber delay time ring, and fiber coupler is dead It is connected with fiber delay time ring during the second step collection data signal of end.

The fiber delay time ring is identical with optical fiber sensitivity ring length.

Normalization correlation function in the step one and step 2 is calculated using below equation, i.e., non-incoming fiber optic time delay The value of Normalized Cross Correlation Function during ring in zero momentNormalized crosscorrelation letter during with incoming fiber optic time delay ring Value of the number in zero momentBelow equation calculating is respectively adopted：

Wherein,WithWhen representing non-incoming fiber optic time delay ring respectively and incoming fiber optic time delay ring When two detector output signals in noise cross-correlation function.

Described source noise cross-correlation function is in zero moment ratio R_optAnd electronic noise cross-correlation function is at zero (0) Carve ratio R_ele(0) below equation calculating is respectively adopted：

Both ratio ks are calculated using below equation：

Wherein,Represent non-incoming fiber optic time delay ring when Normalized Cross Correlation Function zero moment value,Represent incoming fiber optic time delay ring when Normalized Cross Correlation Function zero moment value.

Described source noise Normalized Cross Correlation Function ρ_oWith electronic noise Normalized Cross Correlation Function ρ_eBe respectively adopted with Lower formula is calculated：

Wherein,Represent non-incoming fiber optic time delay ring when Normalized Cross Correlation Function zero moment value,Represent incoming fiber optic time delay ring when Normalized Cross Correlation Function zero moment value, Var [n_A(t)] and Var [n_B(t)] the analog-digital converter output digit signals of signalling channel and light source channels under non-incoming fiber optic time delay ring are represented respectively Variance, Var [n_A' (t)] and Var [n_B' (t)] respectively represent incoming fiber optic time delay ring under signalling channel and light source channels modulus The variance of converter output digit signals, Var [n_e(t)] represent and close signalling channel analog-digital converter output numeral letter under light source Number variance.

Beneficial effects of the present invention：

The present invention for traditional double probe type optical fibre gyro cannot independent measurement source noise correlation so that cannot be accurate The deficiency and problem of subtractive method noise reduction are really evaluated, it is proposed that a kind of new method, in can accurately obtaining two sense channels Source noise Normalized Cross Correlation Function and electronic noise Normalized Cross Correlation Function.So that source noise normalized crosscorrelation letter Several measurements is not disturbed by electronic noise, so that accurate evaluation double detector type optical fibre gyro passes through subtractive method to source noise Inhibitory action.

Brief description of the drawings

Fig. 1 is optical fibre gyro minimum reciprocal system of the present invention.

Fig. 2 is system block diagram when double detector type optical fibre gyro of the invention does not add fiber delay time ring step.

Fig. 3 is system block diagram when double detector type optical fibre gyro of the invention adds fiber delay time ring step.

In figure：Light source 1, fiber coupler 2, Y waveguide 3, optical fiber sensing ring 4, fiber coupler dead end 5, signal sensor 6th, signalling channel analog-digital converter 7, digital signal processor 8, ray detector 9 and light source channel modulus converter 10, optical fiber Time delay ring 11.

Specific embodiment

The invention will be further described with reference to the accompanying drawings and examples.

As shown in figure 1, double detector type optical fibre gyro of the invention includes light source 1, fiber coupler 2, Y waveguide 3, optical fiber Sensing ring 4, signal sensor 6, signalling channel analog-digital converter 7 and digital signal processor 8, the signal of fiber coupler 2 lead to Road connects signal sensor 6, above-mentioned to constitute optical fibre gyro minimum reciprocal system.

Fiber coupler dead end 5 is that fiber coupler 2 is not used in double detector type optical fibre gyro minimum reciprocal system Port, specific experiment calculate correlation when, in the connection fiber delay time ring 11 or light source of the selectivity of fiber coupler dead end 5 Detector 9.Specifically, as shown in Fig. 2 the first step of fiber coupler dead end 5 collection data signal when not with fiber delay time ring Connection；As shown in figure 3, being connected with fiber delay time ring during the second step of fiber coupler dead end 5 collection data signal.

Operation principle of the invention and the course of work are：

Double detector type optical fibre gyro be by light source, fiber coupler, Y waveguide, optical fiber sensing ring, signal sensor, On the basis of the optical fibre gyro minimum reciprocal system of signalling channel analog-digital converter and digital signal processor composition, in optical fiber coupling Clutch dead end increases fiber delay time ring, ray detector and light source channel modulus converter and constitutes.Light source light extraction is through fiber coupling Device is divided into two light beams, and A light beams and B light beams are designated as respectively.It is quick that A light beams enter optical fiber through the two-beam that Y waveguide is divided into reverse transfer Sense ring, fiber coupler entering signal detector is passed through after then closing beam through Y waveguide again.Dead end not incoming fiber optic time delay ring When, B light beams are directly entered ray detector through fiber coupler, and now the passage of A, B two is sampled to two detectors simultaneously, sampling letter Comprising electronic noise in the same time and there is the source noise of time delay in number noise, time delay is the optical fiber sensing ring transition time.Dead end During incoming fiber optic time delay ring, B light beams enter fiber delay time ring through fiber coupler, subsequently into ray detector, fiber delay time Ring is identical with optical fiber sensitivity ring length, therefore is made an uproar comprising light source in the same time in sampled signal noise when being sampled to two detectors simultaneously Sound and mutually electronic noise in the same time.

Not during incoming fiber optic time delay ring, source noise and electronic noise are divided into and are designated as n in A paths detection signals_oA(t) and n_eAT (), overall noise is designated as n_A(t).Source noise and electronic noise are divided into and are designated as n in B paths detection signals_oB(t) and n_eB T (), overall noise is designated as n_B(t).During incoming fiber optic time delay ring, source noise and electronic noise are divided into A paths detection signals It is designated as n_oA' (t) and n_eA' (t), overall noise is designated as n_A′(t).Source noise and electronic noise are divided into note in B paths detection signals It is n_oB' (t) and n_eB' (t), overall noise is designated as n_B′(t).Fiber delay time ring is decayed negligible to source noise.Each noise is expired The following equilibrium relationships of foot：

n_A(t)=n_oA(t)+n_eA(t)

n_B(t)=n_oB(t)+n_eB(t)

n_A' (t)=n_oA′(t)+n_eA′(t)

n_B' (t)=n_oB′(t)+n_eB′(t)

Wherein, t represents the time.

All noises are white noise, and average is 0, i.e.,：

Calculate B paths in non-incoming fiber optic time delay ring, the Normalized Cross Correlation Function of the access detection signal of A, B two

Wherein, τ represents normalization correlation function independent variable, is two time serieses in normalization correlation function calculating process Between time delay.

It is 0 with reference to all noise signal averages because source noise and electronic noise are independent mutually,τ= Value when 0：

Now because light source light extraction does not reach two detectors in the same time, so source noise in amount detector detection signal Correlation function is 0, i.e.,：

E[n_oA(t)n_oB(t)]=0

SoCan abbreviation be：

Same method calculate B paths in incoming fiber optic time delay ring, the normalized crosscorrelation of the access detection signal of A, B two Value of the function at τ=0

Electronic noise is adding fiber delay time ring and is being added without time delay in signal sensor and ray detector detection signal It is identical in the case of two kinds of ring, i.e.,：

E[n_eA′(t)n_eB' (t)]=E [n_eA(t)n_eB(t)]

Therefore,It is changed into：

Thus, source noise and electronic noise correlation k are calculated using below equation：

Source noise Normalized Cross Correlation Function ρ_oWith electronic noise Normalized Cross Correlation Function ρ_eBelow equation is respectively adopted Calculate：

Embodiments of the invention and its implementation process are as follows：

Embodiment verifies that experiment primary condition is as follows by emulation experiment：Two channel source noise variances are 400, return One change cross-correlation function is 0.7 in the value of zero moment；Two channel source noise variances are 200, and Normalized Cross Correlation Function exists The value of zero moment is 0.9, and fiber delay time ring acts through host computer the Realization of Simulation.

First, according to connection system shown in Fig. 2, now fiber delay time ring is not accessed.To signal sensor and light source detection Device is sampled simultaneously, and sample sequence is { n_A(t) } and { n_B(t) }, calculate its variance Var [n_A(t)] and Var [n_B(t)] be：

And calculate signal sensor and ray detector sampled data normalization correlation function beFor：

Then, as shown in figure 3, adding fiber delay time ring, sample sequence is { n_A' (t) } and { n_B' (t) }, calculate its variance Var[n_A' (t)] and Var [n_B' (t)] be：

And calculate signal sensor and ray detector sampled data normalization correlation function beFor：

Electronic noise and source noise correlation k are：

Source noise Normalized Cross Correlation Function ρ_oWith electronic noise Normalized Cross Correlation Function ρ_eBelow equation is respectively adopted Calculate：

Embodiment result compared with setting value 0.7 and 0.9 set in advance is emulated, it can be seen that phase in computational accuracy Deng the inventive method accuracy thus can be explained high.

And if being with the two access detection signal correlations of data calculating collected when adding fiber optic loop directly nowWherein contain electronic noise and source noise collective effect, it is impossible to respectively obtain source noise and The respective Normalized Cross Correlation Function of electronic noise.As can be seen here, light source is made an uproar during the present invention can accurately obtain two sense channels Acoustic correlation is strong and weak, and without being disturbed by electronic noise, accurate acquisition double detector type optical fibre gyro is made an uproar by subtractive method to light source The inhibitory action of sound.

Claims (7)

1. it is a kind of to separate double detector type optical fibre gyro light source and electronic noise correlation calculations method, double detector type optical fiber top Spiral shell includes light source (1), fiber coupler (2), Y waveguide (3), optical fiber sensing ring (4), signal sensor (6), signalling channel modulus Converter (7) and digital signal processor (8), it is characterised in that：

Step one, double detector type optical fibre gyro dead end successively through ray detector (9), light source channel modulus converter (10) digital signal processor (8) is connected to after, respectively by signalling channel analog-digital converter (7) and light source channels analog-to-digital conversion Device (10) exports respective data signal, is calculated in digital signal processor (8) two under obtaining non-incoming fiber optic time delay ring Variance Var [the n of channel modulus converter output digit signals_A(t)] and Var [n_B(t)] and Normalized Cross Correlation Function zero The value at momentVar[n_A(t)] represent signal sensor data signal variance, Var [n_B(t)] represent light source The variance of the data signal of detector；

Step 2, double detector type optical fibre gyro dead end successively through fiber delay time ring (11), ray detector (9), light source Digital signal processor (8) is connected to after channel modulus converter (10), passes through signalling channel analog-digital converter (7) respectively again Respective data signal is exported with light source channel modulus converter (10), is calculated in digital signal processor (8) and is accessed Two variance Var [n of channel modulus converter output digit signals under fiber delay time ring_A' (t)] and Var [n_B' (t)] and return One changes value of the cross-correlation function in zero moment

Step 3, close light source power supply, now signalling channel signal sensor output electric signal only comprising electronic noise without Comprising source noise, the data signal n exported by signalling channel analog-digital converter (7)_e(t), in digital signal processor (8) It is middle to calculate the variance Var [n that signalling channel analog-digital converter (7) output digit signals under light source are closed in acquisition_e(t)]；

Step 4, the variance with above-mentioned gained and Normalized Cross Correlation Function value carry out computing, obtain source noise cross-correlation letter Number is in zero moment ratio R_optAnd electronic noise cross-correlation function is in zero moment ratio R (0)_ele(0), both ratio k=R_opt(0)/ R_ele(0)；

Step 5, the variance with above-mentioned gained, Normalized Cross Correlation Function value and ratio k carry out computing, respectively obtain light source and make an uproar Sound Normalized Cross Correlation Function ρ_oWith electronic noise Normalized Cross Correlation Function ρ_e。

2. one kind according to claim 1 separates double detector type optical fibre gyro light source and electronic noise correlation calculations side Method, it is characterised in that：Described double detector type optical fibre gyro is by light source (1), fiber coupler (2), Y waveguide (3), light The optical fiber of fine sensing ring (4), signal sensor (6), signalling channel analog-digital converter (7) and digital signal processor (8) composition In gyro minimum reciprocal system-based, fiber coupler dead end (5) connect fiber delay time ring (11), ray detector (9) and Light source channel modulus converter (10) is formed.

3. one kind according to claim 1 separates double detector type optical fibre gyro light source and electronic noise correlation calculations side Method, it is characterised in that：The fiber coupler dead end (5) is the optical fiber coupling in double detector type optical fibre gyro minimum reciprocal system The port that clutch (2) is not used, does not connect during fiber coupler dead end (5) first step collection data signal with fiber delay time ring Connect, be connected with fiber delay time ring during fiber coupler dead end (5) second step collection data signal.

4. one kind according to claim 1 separates double detector type optical fibre gyro light source and electronic noise correlation calculations side Method, it is characterised in that：The fiber delay time ring (11) is identical with optical fiber sensing ring (4) length.

5. one kind according to claim 1 separates double detector type optical fibre gyro light source and electronic noise correlation calculations side Method, it is characterised in that：In the step one and step 2, i.e., non-incoming fiber optic time delay ring when Normalized Cross Correlation Function zero The value at momentThe value of Normalized Cross Correlation Function during with incoming fiber optic time delay ring in zero momentPoint Cai Yong not below equation calculating：

${\mathrm{\ρ}}_{n_A\left(t\right)n_B\left(t\right)}\left(0\right)=\frac{R_{n_A\left(t\right)n_B\left(t\right)}\left(0\right)}{\sqrt{Var\[n_A\left(t\right)\]\·Var\[n_B\left(t\right)\]}}$

${\mathrm{\ρ}}_{{n_A}^{\′}\left(t\right){n_B}^{\′}\left(t\right)}\left(0\right)=\frac{R_{{n_A}^{\′}\left(t\right){n_B}^{\′}\left(t\right)}\left(0\right)}{\sqrt{Var\[{n_A}^{\′}\left(t\right)\]\·Var\[{n_B}^{\′}\left(t\right)\]}}$

Wherein,WithWhen representing non-incoming fiber optic time delay ring respectively and during incoming fiber optic time delay ring The cross-correlation function of noise in two detector output signals.

6. one kind according to claim 1 separates double detector type optical fibre gyro light source and electronic noise correlation calculations side Method, it is characterised in that：Described source noise cross-correlation function is in zero moment ratio R_optAnd electronic noise cross-correlation function (0) In zero moment ratio R_ele(0) below equation calculating is respectively adopted：

$R_{opt}\left(0\right)={\mathrm{\ρ}}_{{n_A}^{\′}\left(t\right){n_B}^{\′}\left(t\right)}\left(0\right)\sqrt{Var\[{n_A}^{\′}\left(t\right)\]\·Var\[{n_B}^{\′}\left(t\right)\]}-{\mathrm{\ρ}}_{n_A\left(t\right)n_B\left(t\right)}\left(0\right)\sqrt{Var\[n_A\left(t\right)\]\·Var\[n_B\left(t\right)\]}$

$R_{ele}\left(0\right)={\mathrm{\ρ}}_{n_A\left(t\right)n_B\left(t\right)}\left(0\right)\sqrt{Var\[n_A\left(t\right)\]\·Var\[n_B\left(t\right)\]}$

Both ratio ks are calculated using below equation：

$k=\frac{R_{opt}\left(0\right)}{R_{ele}\left(0\right)}=\frac{{\mathrm{\ρ}}_{{n_A}^{\′}\left(t\right)n_B^{\′}\left(t\right)}\left(0\right)\sqrt{Var\[{n_A}^{\′}\left(t\right)\]\·Var\[{n_B}^{\′}\left(t\right)\]}}{{\mathrm{\ρ}}_{n_A\left(t\right)n_B\left(t\right)}\left(0\right)\sqrt{Var\[n_A\left(t\right)\]\·Var\[n_B\left(t\right)\]}}-1$

Wherein,Represent non-incoming fiber optic time delay ring when Normalized Cross Correlation Function zero moment value,Represent incoming fiber optic time delay ring when Normalized Cross Correlation Function zero moment value.

7. one kind according to claim 1 separates double detector type optical fibre gyro light source and electronic noise correlation calculations side Method, it is characterised in that：Described source noise Normalized Cross Correlation Function ρ_oWith electronic noise Normalized Cross Correlation Function ρ_eRespectively Calculated using below equation：

${\mathrm{\ρ}}_o=\frac{k}{k+1}\·\frac{{\mathrm{\ρ}}_{{n_A}^{\′}\left(t\right)n_B^{\′}\left(t\right)}\left(0\right)\sqrt{Var\[{n_A}^{\′}\left(t\right)\]\·Var\[{n_B}^{\′}\left(t\right)\]}}{Var\[{n_A}^{\′}\left(t\right)\]-Var\[n_e\left(t\right)\]}$

${\mathrm{\ρ}}_e=\frac{1}{k+1}\·\frac{{\mathrm{\ρ}}_{{n_A}^{\′}\left(t\right)n_B^{\′}\left(t\right)}\left(0\right)\sqrt{Var\[{n_A}^{\′}\left(t\right)\]\·Var\[{n_B}^{\′}\left(t\right)\]}}{Var\[n_e\left(t\right)\]}$

Wherein,Represent non-incoming fiber optic time delay ring when Normalized Cross Correlation Function zero moment value,Represent incoming fiber optic time delay ring when Normalized Cross Correlation Function zero moment value, Var [n_A(t)] and Var [n_B(t)] the analog-digital converter output digit signals of signalling channel and light source channels under non-incoming fiber optic time delay ring are represented respectively Variance, Var [n_A' (t)] and Var [n_B' (t)] respectively represent incoming fiber optic time delay ring under signalling channel and light source channels modulus The variance of converter output digit signals, Var [n_e(t)] represent and close signalling channel analog-digital converter (7) output number under light source The variance of word signal.