CN106052670A - Active anti-radiation design method of interference type digital closed-loop fiber-optic gyroscope - Google Patents

Abstract

The invention provides an active anti-radiation design method of an interference type digital closed-loop fiber-optic gyroscope. The active anti-radiation design method is used in the technical field of interference type fiber-optic gyroscopes. The active anti-radiation design method firstly provides an improved random walk coefficient prediction model, and random walk coefficients under space radiation conditions are directly calculated by substituting radiation environment parameters into the model; then margin design is conducted on the three parameters of light source power, optical fiber length and phase modulation under the radiation condition based on the random walk coefficient prediction model, and reduction of the random walk coefficients of the interference type fiber-optic gyroscope is achieved. The active anti-radiation design method is based on an original structure of the interference type fiber-optic gyroscope, and the random walk coefficients of the interference type fiber-optic gyroscope can be reduced under the condition that no additional device is added, so that the fiber-optic gyroscope used in a space meets the system requirement for the random walk performance of the gyroscope within a whole life cycle, the active anti-radiation purpose is achieved, the gyroscope has high reliability, and the overall size and power consumption of the interference type fiber-optic gyroscope are reduced.

Description

A kind of interference formula digital closed-loop optic fiber gyroscope Active anti-radiation method for designing

Technical field

The present invention relates to interference type optical fiber gyroscope technical field, be specifically related to a kind of based on random walk coefficient forecast model Interference formula digital closed-loop optic fiber gyroscope Active anti-radiation method for designing.

Background technology

Interference type optical fiber gyroscope is a kind of low-power consumption, optical gauge highly reliable, high-precision, utilizes fiber optic loop sensitive Treat angular velocity, produce phase contrast that there is the advantages such as movement-less part, dynamic range be big, life-span length, shock resistance, resistant to overload, can It is widely used in space industry.Fig. 1 is the structural representation of typical interference type optical fiber gyroscope, mainly include light source, bonder, Y waveguide, fiber optic loop, detector and signal processing apparatus.In spatial environments, interference type optical fiber gyroscope is affected relatively big by space radiation, Cause fibre loss increase, light source power to decline and detector responsivity reduces, thus cause interference type optical fiber gyroscope performance Deterioration, shows that Gyro Random migration coefficient increases and output signal offset drift.Although spatial calibration can be to most Long-term offset drift compensates, but cannot reduce the random walk coefficient of gyro, causes the essence of the optical fibre gyro of Space-Work Degree deteriorates in time, it is impossible to meet under space radiation environment satellite to gyro long-life, the demand of high reliability, it is therefore desirable to right Gyro carries out radioprotective and Redundancy Design.

Impurity ion is focused primarily upon currently for the radiation-hardened design method interfering formula digital closed-loop optic fiber gyroscope The passive enforcement technology of the optical fiber such as method, photofading heart method, but in practical engineering application, there is cost height and be unfavorable in reinforcement technique Mass production, capability of resistance to radiation is weak is unfavorable for that space is applied, and extra device causes interference type optical fiber gyroscope volume and power consumption Raise, the problem such as reliability reduction.

Summary of the invention

For existing issue, the present invention devises a kind of interference formula digital closed loop optical fiber top that need not additionally increase device The Active anti-radiation method for designing of spiral shell.The inventive method is based on random walk coefficient forecast model, by right under radiation condition Light source power, fiber lengths, three parameters of phase modulation carry out margin design, make space with optical fibre gyro in life cycle management Meet the system requirement to Gyro Random migration performance.

A kind of interference formula digital closed-loop optic fiber gyroscope Active anti-radiation method for designing that the present invention provides, first provides a kind of The random walk coefficient forecast model improved, as follows:

$\begin{array}{c}RWC\\ =\frac{(\mathrm{\λ}c/2\mathrm{\π}LD)\sqrt{\left(2e{\left(1+\cos \mathrm{\φ}\right)}^2\right)/\left({\mathrm{\ηP}}_0{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/10}{\left(\sin \mathrm{\φ}\right)}^2\right)+\left({\left(1+\cos \mathrm{\φ}\right)}^2\right)/\left(\mathrm{\Δ}v{\left(\sin \mathrm{\φ}\right)}^2\right)}}{+\left(2{\mathrm{eI}}_d\right)/\left({\left({\mathrm{\ηP}}_0{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/10}\sin \mathrm{\φ}\right)}^2\right)+\left(4kT\right)/\left(R{\left({\mathrm{\ηP}}_0{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/10}\sin \mathrm{\φ}\right)}^2\right)}\end{array}$

Wherein, RWC represents the random walk coefficient of optical fibre gyro, and λ represents that optical wavelength, c represent light propagation in a vacuum Speed, L represents fiber optic loop length, and D represents fiber optic loop diameter, and e represents that electron charge, φ represent square-wave frequency modulation phase place, and η represents spy Survey the responsiveness of device, P₀Representing the light source power being coupled into light path, Δ v represents light source spectral bandwidth, I_dRepresent that detector is the most electric Stream, k represents that Boltzmann constant, T represent that absolute temperature, R represent that detector is across resistance, A_iRepresent the internal loss of fiber optic loop, A_cTable Show by optical path losses whole produced by fiber coupler, integrated optical circuit and weld；Q, b, f are constants, and d is radiation agent Amount, r is radiation dose rate.

Secondly, in the production process of gyro, for parameter light source power P₀, fiber optic loop length L and phase modulation φ enter Row margin design, it is achieved the reduction of the random walk coefficient of interference type optical fiber gyroscope.

According to the function expression of fiber optic loop length L under the conditions of space radiationSolve letter Number extreme value carries out margin design to fiber optic loop length, obtains optimum fiber optic loop length L_op。

Light source power and phase modulation are carried out margin design, including step (1)～step (4)；

Step (1) is by calculated optimum fiber optic loop length L_opThe random trip improved is substituted into space radiation parameter r, d Walk coefficient prediction model, obtain light source power and phase modulation relational expression, and carry out fitting of a polynomial；

The light source power P that step (2) will set₀Initial value substitute into matching multinomial in, solve optimal modulation phase place；

Step (3) sets Max (RWC) as currently meeting the maximum of the random walk coefficient of space tasks, if Max (RWC) required random walk coefficient RWC properly functioning more than or equal to interference type optical fiber gyroscope_q, perform step (4)；If Max (RWC) less than RWC_q, now random walk coefficient meets space tasks requirement, method ends；

Step (4) increases light source power, substitutes in the multinomial of matching and solves optimal modulation phase place, enters back into step (3) Perform.

It is an advantage of the current invention that:

(1) present invention original structure based on interference type optical fiber gyroscope, under conditions of without any additional devices i.e. The random walk coefficient of optical fibre gyro can be reduced, and then reach the purpose of design of Active anti-radiation；

(2) a kind of novel random walk coefficient model is proposed, and based on this model, the side designed by Stability margin of parameter Method, meets the interior requirement to random walk performance of optical fibre gyro life cycle management；

(3) present invention need not add extra Flouride-resistani acid phesphatase device, existing higher reliability, also reduces interference formula light The volume of fine gyro entirety and power consumption.

Accompanying drawing explanation

Fig. 1 is the structural representation of typical interference type optical fiber gyroscope；

Fig. 2 is present invention Stability margin of parameter design flow diagram based on novel random walk coefficient model；

Fig. 3 is to use Active anti-radiation method of the present invention and be provided without the experiment interference type optical fiber gyroscope of radioprotective method Random walk coefficient comparison diagram.

Detailed description of the invention

Below in conjunction with accompanying drawing, the present invention is described in further detail.

The random walk coefficient (RWC) of optical fibre gyro is by shot noise, light source intensity noise, the warm of explorer load resistance Noise and detector dark current noise are constituted, and use the random walk system of the interference formula digital closed-loop optic fiber gyroscope of square-wave frequency modulation Number RWC can be expressed as:

$RWC=\frac{\mathrm{\λ}c}{2\mathrm{\π}LD}\sqrt{\frac{2e{(1+cos\mathrm{\φ})}^2}{I{\left(sin\mathrm{\φ}\right)}^2}+\frac{{(1+cos\mathrm{\φ})}^2}{\mathrm{\Δ}v{\left(sin\mathrm{\φ}\right)}^2}+\frac{2{\mathrm{eI}}_d}{{\left(Isin\mathrm{\φ}\right)}^2}+\frac{4kT}{R{\left(Isin\mathrm{\φ}\right)}^2}}---\left(1\right)$

Wherein, k represents that Boltzmann constant, T represent that absolute temperature, e represent that electron charge, Δ v represent light source spectral band Width, λ represents that optical wavelength, c represent light spread speed in a vacuum, and R represents that detector is across resistance, I_dRepresent detector dark current, L Representing fiber optic loop length, D represents fiber optic loop diameter, and φ represents square-wave frequency modulation phase place, and I is the photoelectric current arriving detector, permissible It is expressed as:

$I=\mathrm{\η}{P}_0{10}^{-[A_c+(A_i+A)L]/10}---\left(2\right)$

Wherein, P₀Representing the light source power being coupled into light path, η represents the responsiveness of detector, and A represents the radiation of fiber optic loop Induced attenuation, A_iRepresent the internal loss of fiber optic loop, A_cRepresent and produced by other parts such as fiber coupler, integrated optical circuit and weldings Raw whole optical path losses.Between radiation induced attenuation and radiation dose and radiation dose rate in known fiber optic ring, relation is as follows:

A=qr^bd^f (3)

Wherein, q, b, f are constants, and d is radiation dose, and r is radiation dose rate.Expression formula (2) and (3) are substituted into formula (1) In, obtain a kind of novel random walk coefficient model, as shown in formula (4), the model describe interference type optical fiber gyroscope random Migration coefficient Changing Pattern under radiation condition.

$\begin{array}{c}RWC\\ =\frac{(\mathrm{\λ}c/2\mathrm{\π}LD)\sqrt{\left(2e{\left(1+\cos \mathrm{\φ}\right)}^2\right)/\left({\mathrm{\ηP}}_0{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/10}{\left(\sin \mathrm{\φ}\right)}^2\right)+\left({\left(1+\cos \mathrm{\φ}\right)}^2\right)/\left(\mathrm{\Δ}v{\left(\sin \mathrm{\φ}\right)}^2\right)}}{+\left(2{\mathrm{eI}}_d\right)/\left({\left({\mathrm{\ηP}}_0{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/10}\sin \mathrm{\φ}\right)}^2\right)+\left(4kT\right)/\left(R{\left({\mathrm{\ηP}}_0{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/10}\sin \mathrm{\φ}\right)}^2\right)}\end{array}---\left(4\right)$

Space radiation is to increase fiber optic loop loss to the main impact of random walk coefficient, therefore by known optical fiber radiation Sensitive parameter q, b, f and radiation environment parameter r, d substitute into formula (4), i.e. can get gyro random walk under radiation environment Coefficient.Wherein, radiation environment parameter r, d can be according to orbit altitude, effective time of launch and equivalence aluminum ball protective cover thickness estimations Obtain.

The most existing formula (1), the formula (4) that the present invention provides, give interference type optical fiber gyroscope at space radiation ring The expression formula of random walk coefficient under border, and can by substitute into radiation environment parameter, directly calculating space radiation under the conditions of with Machine migration coefficient.

Traditional interference type optical fiber gyroscope is mainly affected by shot noise and light source intensity noise.Space radiation causes Fiber optic loop loss increases, thus causes the increase of shot noise, and it is too small to ultimately result in the luminous power that photodetector detects. From formula (1) it can be seen that the light source intensity noise interference type optical fiber gyroscope is unrelated with fibre loss.Therefore, according to formula (4) The novel random walk coefficient model proposed, under the conditions of space radiation, the random walk coefficient of interference type optical fiber gyroscope is mainly joined Number η, Δ v, D, λ P₀, the impact of L and φ, wherein in the production process of gyro, for parameter light source power P₀, fiber optic loop length L and phase modulation φ carries out margin design, can realize the reduction of the random walk coefficient of interference type optical fiber gyroscope.

The interference formula digital closed-loop optic fiber gyroscope based on random walk coefficient forecast model that the present invention provides actively anti-spoke Penetrate method for designing, specifically comprise the following steps that

Step 1: fiber optic loop length margin design, specifically:

According to novel random walk coefficient forecast model, in space radiation environment, random walk coefficient is mainly by shot Effect of noise, to simplify the analysis, ignores the impact of intensity noise, dark current noise and thermal noise, and random walk coefficient can To be expressed as:

$RWC\≈\frac{\mathrm{\λ}c}{2\mathrm{\π}LD}\sqrt{\frac{2e{(1+cos\mathrm{\φ})}^2}{{\mathrm{\ηP}}_0{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/10}{\left(\sin \mathrm{\φ}\right)}^2}}---\left(5\right)$

Known shot noise is relevant to fiber optic loop length, and in formula (5), the function about fiber optic loop length L can represent For:

$F\left(L\right)=L{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/20}---\left(6\right)$

Fiber optic loop length is the unique variable in formula (5), therefore can obtain random noise by seeking F (L) maximum The minima of coefficient, optimum fiber optic loop length L_opCan be expressed as:

$\frac{dF\left(L\right)}{dL}\left(L_{op}\right)=0---\left(7\right)$

Final result can be expressed as:

$L_{op}=\frac{8.68}{A_i+{\mathrm{qr}}^b{d}^f}---\left(8\right)$

Step 2: the margin design of phase modulation numerical solution, specifically:

Step 2.1, by calculated for step 1 optimum fiber optic loop length, space radiation parameter r that estimation obtains, d and Interference type optical fiber gyroscope other have determined that parameter (η, Δ v, D, λ P₀、T、R、I_d、q、b、f、A_iAnd φ) substitute into shown in formula (4) Novel random walk coefficient forecast model, obtains light source power and phase modulation relational expression, and it is many to fit to a quadravalence Item formula.

Step 2.2, the primary light source power P of setting₀Substitute in matching quartic polynomial, solve optimal modulation phase place.

Step 2.3, if the maximum that Max (RWC) is the random walk coefficient currently meeting space tasks, can be according to space Task condition calculates and obtains, if random walk coefficient maximum Max (RWC) is more than or equal to RWC_q, perform step 2.4；RWC_q Represent the value of the properly functioning required random walk coefficient of interference type optical fiber gyroscope.When Max (RWC) is less than RWC_qTime, random walk Coefficient meets space tasks requirement, terminates margin design.

Step 2.4, increases light source power, again substitutes in the quartic polynomial of matching, resolve new optimal modulation phase place, Perform subsequently into step 2.3, until random walk coefficient maximum Max (RWC) is less than RWC_q。

As it is shown on figure 3, under the conditions of for using Active anti-radiation method and being provided without radioprotective method, experiment interference formula light Fine Gyro Random migration index contrast figure.In Fig. 3, abscissa represents that radiation dose, vertical coordinate represent random walk coefficient RWC.From In figure it can be seen that by use the present invention provide Active anti-radiation method, to fiber lengths, phase modulation and light source power Carry out margin design, reduced the random walk coefficient of interference type optical fiber gyroscope, and then can reach the purpose of Active anti-radiation.

Claims (1)

1. interfere formula digital closed-loop optic fiber gyroscope Active anti-radiation method for designing for one kind, it is characterised in that realize step as follows:

(1) the random walk coefficient forecast model of a kind of improvement is provided, is shown below:

$\begin{array}{c}RWC\\ =\frac{(\mathrm{\λ}c/2\mathrm{\π}LD)\sqrt{\left(2e{\left(1+\cos \mathrm{\φ}\right)}^2\right)/\left({\mathrm{\ηP}}_0{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/10}{\left(\sin \mathrm{\φ}\right)}^2\right)+\left({\left(1+\cos \mathrm{\φ}\right)}^2\right)/\left(\mathrm{\Δ}v{\left(\sin \mathrm{\φ}\right)}^2\right)}}{+\left(2{\mathrm{eI}}_d\right)/\left({\left({\mathrm{\ηP}}_0{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/10}\sin \mathrm{\φ}\right)}^2\right)+\left(4kT\right)/\left(R{\left({\mathrm{\ηP}}_0{10}^{-\[A_c+(A_i+{\mathrm{qr}}^b{d}^f)L\]/10}\sin \mathrm{\φ}\right)}^2\right)}\end{array}$

Wherein, RWC represents the random walk coefficient of optical fibre gyro, and λ represents that optical wavelength, c represent light spread speed in a vacuum, L represents fiber optic loop length, and D represents fiber optic loop diameter, and e represents that electron charge, φ represent square-wave frequency modulation phase place, and η represents detector Responsiveness, P₀Representing the light source power being coupled into light path, Δ v represents light source spectral bandwidth, I_dRepresent detector dark current, k table Show that Boltzmann constant, T represent that absolute temperature, R represent that detector is across resistance；A_iRepresent the internal loss of fiber optic loop, A_cRepresent by light Whole optical path losses produced by fine bonder, integrated optical circuit and weld, q, b, f are constants, and d is radiation dose, and r is spoke Penetrate close rate；

(2) in the production process of gyro, for parameter light source power P₀, fiber optic loop length L and phase modulation φ carry out nargin and set Meter, it is achieved the reduction of the random walk coefficient of interference type optical fiber gyroscope；

According to the function expression of fiber optic loop length L under the conditions of space radiationSolved function pole Value carries out margin design to fiber optic loop length, obtains optimum fiber optic loop length L_op；

Light source power and phase modulation are carried out margin design, including step (1)～step (4)；

Step (1) is by calculated optimum fiber optic loop length L_opThe random walk system improved is substituted into space radiation parameter r, d Number forecast model, obtains light source power and phase modulation relational expression, and carries out fitting of a polynomial；

The light source power P that step (2) will set₀Initial value substitute into matching multinomial in, solve optimal modulation phase place；

Step (3) sets Max (RWC) as currently meeting the maximum of the random walk coefficient of space tasks, if Max (RWC) is big In or required random walk coefficient RWC properly functioning equal to interference type optical fiber gyroscope_q, perform step (4)；If Max (RWC) is little In RWC_q, now random walk coefficient meets space tasks requirement, method ends；

Step (4) increases light source power, substitutes in the multinomial of matching and solves optimal modulation phase place, enters back into step (3) and performs.