CN100580377C - Method for expanding open loop optical fiber gyroscope dynamic range - Google Patents

Abstract

The invention discloses a method for expanding dynamic range of a ring-opening optical fiber gyro, which adopts a periodical phase modulation for the ring-opening optical fiber gyro, wherein a phase modulating single comprises five modulating steps whose modulating amplitudes are different and duration is a transit time of the ring-opening optical fiber gyro. A system single output which is corresponded to the five modulating steps is obtained by a sample circuit, a correct resolving algorithm of a resolving interval is chose to solve, and a match standard naik phase is obtained after the system is expanded through the dynamic range. The resolving interval is chosen according to the matched standard naik phase which is demodulated by a former modulating period, and a selection of the resolving interval utilizes a recursive method, a common interval is introduced between adjacent resolving intervals, and the reliability of the optical fiber gyro can be improved when the dynamic range of the optical fiber gyro is expanding. The method need not to change hardware, namely the dynamic range of the optical fiber gyro is expanded to 23/8 times than the original optical fiber gyro, which can test angular speed which is faster than 1000 degrees, the range of the test is improved, and the invention has high practical value.

Description

The method of expanding open loop optical fiber gyroscope dynamic range

Technical field

The present invention relates to the signal processing method in the optical fibre gyro sensor, especially relate to a kind of method of expanding open loop optical fiber gyroscope dynamic range.

Background technology

Optical fibre gyro is a kind of novel angular rate measuring device, its principle of work is based on the fibre optic interferometer of optics match lattice Neck effect, promptly when ring interferometer rotates, produce a phase differential that is proportional to angular velocity of rotation, by detecting this phase differential, can obtain the angular velocity of ring interferometer place system.Because it is big and have the advantage of various protocols numeral output that optical fibre gyro has all solid state, bandwidth, is widely used in navigation and the attitude control system.

The intrinsic response function of optical fibre gyro is a cosine function, but for the linearity and the sensitivity that improves Optical Fiber Gyroscope, generally optical fibre gyro is carried out square-wave frequency modulation, on the phase bias of it is operated in the sensitiveest ± pi/2, this moment, the output of optical fibre gyro can be expressed as.

I wherein ₀Be system's average output signal, I is the output signal of system's reality, φ _SagFor rotating the match lattice Neck phase shift that produces, ± pi/2 is the dynamic phasing biasing.By can obtaining matching the size of lattice Neck phase shift to the demodulation of Optical Fiber Gyroscope, and the relation of match lattice Neck phase shift and angular velocity can be expressed as follows:

${\mathrm{\φ}}_{\mathrm{Sag}}=\frac{2\mathrm{\πLD}}{\mathrm{\λc}}\mathrm{\Ω}---\left(2\right)$

Wherein L is an optical fibre gyro fiber optic loop fiber lengths, and D is the fiber optic loop diameter, and the used optical source wavelength of λ optical fibre gyro, c are the light velocity in the vacuum, and Ω is a system angle speed.

The dynamic range of optical fibre gyro refers to the scope of the angular velocity that optical fibre gyro can be measured, because optical fibre gyro intrinsic response function is a cosine function, its monotony interval scope is π, and the angular velocity range of this monotony interval correspondence is the dynamic range of optical fibre gyro.Dynamic phasing biasing down dynamic range be corresponding to [pi/2, pi/2) angular velocity range of phase place, can calculate the dynamic range scope according to (2) and be $\mathrm{\&Omega;}\&Element;[-\frac{\mathrm{\&lambda;<figure-callout\; id="4"\; label="c"\; filenames="C2007101603670011H2.png"\; state="\{\{state\}\}">c</figure-callout>}}{4\mathrm{LD}},+\frac{\mathrm{\&lambda;<figure-callout\; id="4"\; label="c"\; filenames="C2007101603670011H2.png"\; state="\{\{state\}\}">c</figure-callout>}}{4\mathrm{LD}}).$

Dynamic range and used fiber optic loop fiber lengths L and the long-pending of diameter D are inversely proportional to, for fiber optic loop length is 1 km, diameter is 0.1 meter, and optical source wavelength is 0.85 micron a typical high-precision optical fiber gyro, and dynamic range is [36 °/second, 36 °/second], for fiber optic loop length is 100 meters, and diameter is 0.06 meter, and optical source wavelength is 0.85 micron a middle low-precision optical fiber gyro, dynamic range is [600 °/second, 600 °/second].If need bigger dynamic range, then need to reduce fiber lengths or fiber optic loop diameter, but too small fiber optic loop diameter can cause system's bending loss to increase and signal to noise ratio (S/N ratio) reduces, and weakens the precision of optical fibre gyro output angle rate signal; And shorter fiber lengths requires modulation speed faster, requires the subsequent process circuit resolving ability more powerful, increases the complexity and the difficulty of circuit hardware system, introduces more electromagnetic coupled, has caused the increase in potential dead band.

As seen the method that reduces fiber optic loop length and diameter enlarges dynamic range and impracticable, in fact fiber optic loop length is less than 100 meters, diameter can't practicability because technical difficulty is excessive less than 0.06 meter optical fibre gyro, and in some high maneuverability motion carrier, the angular velocity of measuring 1000 °/second-time is again a current demand, thereby requirement can have a kind of new technical method, can not increase the existing hardware design difficulty and reduce system performance, dynamic range that can expanding optical fibre gyroscope, realization is measured accurate this of the big angular velocity of similar thousands of °/second-time, to satisfy the application demand of high maneuverability motion carrier.

Summary of the invention

In present optical fibre gyro research, the high maneuverability motion carrier needs accurately to measure up to thousands of °/angular velocity of second-time, and there is not a present situation of practical simple realization method, the object of the present invention is to provide the method for expanding open loop optical fiber gyroscope dynamic range, do not increasing the hardware design difficulty and reducing on the basis of precision, realization is accurately measured big angular velocity, to satisfy the application demand of high maneuverability motion carrier.

Inventive principle:

Optical fibre gyro is carried out the phase modulation (PM) of a plurality of different amplitudes, comprising original ± pi/2 dynamic phasing biasing, and the output signal of gyro under these phase modulation (PM) sampled, handle and combined method by suitable data, the monotony interval scope of expanding system, eliminate monotony interval be subject to [pi/2～pi/2) and the limited problem of dynamic range.

Change the phase bias signal of optical fibre gyro system, make a modulation cycle contain 5 modulation steps, the phase modulation (PM) amplitude of each modulation step is in turn :-7 π/8,-pi/2,0 ,+pi/2, + 7 π/8, be labeled as A, B, C, D, E modulation step respectively, the duration of each modulation step is the transit time τ of optical fibre gyro, also is that the expression formula of phase modulated signal mod (t) t variation in time is as follows:

$\mathrm{mod}\left(t\right)=\left\{\begin{array}{cc}+15\mathrm{\&pi;}/8& t\&Element;[5\mathrm{n\&tau;},5\mathrm{n\&tau;}+\mathrm{\&tau;})\\ +\mathrm{\&pi;}/2,& t\&Element;[5\mathrm{n\&tau;}+\mathrm{\&tau;},5\mathrm{n\&tau;}+2\mathrm{\&tau;})\\ 0,& t\&Element;[5\mathrm{n\&tau;}+2\mathrm{\&tau;},5\mathrm{n\&tau;}+3\mathrm{\&tau;})\\ -\mathrm{\&pi;}/2,& t\&Element;[5\mathrm{n\&tau;}+3\mathrm{\&tau;},5\mathrm{n\&tau;}+4\mathrm{\&tau;})\\ -15\mathrm{\&pi;}/8,& t\&Element;[5\mathrm{n\&tau;}+4\mathrm{\&tau;},5\mathrm{n\&tau;}+5\mathrm{\&tau;})\end{array}\right.---\left(3\right)$

Wherein n is a positive integer, the sequence number in expression modulation cycle, and τ is the transit time of optical fibre gyro.The output signal of optical fibre gyro is expressed as under the modulation of modulation phase signal mod (t):

I(t)＝I ₀{1+cos[mod(t)+φ _sag]} (4)

I wherein ₀Be the mean value of optical fibre gyro system output signal, φ _SagThe match lattice Neck phase shift that is produced for optical fibre gyro place system angle speed.According to five modulation steps is a modulation cycle, and the sample circuit by optical fibre gyro is captured in five signals in the modulation step and is respectively IA (n), IB (n), IC (n), ID (n), IE (n).The difference function that makes O1 (n), O2 (n), O3 (n) be respectively three groups of modulation step array output signals is:

$O1\left(n\right)=\mathrm{IA}\left(n\right)-\mathrm{IC}\left(n\right)=I_0[\cos (+\frac{15\mathrm{\&pi;}}{8}+{\mathrm{\&phi;}}_{\mathrm{sag}})-\cos \left({\mathrm{\&phi;}}_{\mathrm{sag}}\right)]=-2I_0\sin \left(\frac{15\mathrm{\&pi;}}{16}\right)\sin ({\mathrm{\&phi;}}_{\mathrm{sag}}+\frac{15\mathrm{\&pi;}}{16})$

O2(n)＝IB(n)-ID(n)＝I ₀[cos(π/2+φ _sag)-cos(-π/2+φ _sag)]＝-2I ₀sin(φ _sag) (5)

$O3\left(n\right)=\mathrm{IC}\left(n\right)-\mathrm{IE}\left(n\right)=I_0[\cos \left({\mathrm{\&phi;}}_{\mathrm{sag}}\right)-\cos (-\frac{15\mathrm{\&pi;}}{8}+{\mathrm{\&phi;}}_{\mathrm{sag}})]=-2I_0\sin \left(\frac{15\mathrm{\&pi;}}{16}\right)\sin ({\mathrm{\&phi;}}_{\mathrm{sag}}-\frac{15\mathrm{\&pi;}}{16})$

O1 (n), O2 (n), three functions of O3 (n) monotony interval separately are respectively as can be known: a left side is interval: [23 π/16～-7 π/16), middle interval: [pi/2～pi/2), right interval: [7 π/16～23 π/16), wherein O1 (n), O2 (n) have common interval [pi/2～-7 π/16), O2 (n), O3 (n) have common interval [7 π/16～pi/2).Just according to this three formula can resolve respectively obtain corresponding to [23 π/16～-7 π/16), [pi/2～pi/2), [7 π/16～23 π/16) match lattice Neck phase region between angular velocity, the three φ as a result that resolves separately _Sag1(n), φ _Sag2(n), φ _Sag3(n) as follows respectively:

${\mathrm{\&phi;}}_{\mathrm{sag}1}\left(n\right)=-\frac{15\mathrm{\&pi;}}{16}+{\sin }^{-1}\frac{\mathrm{IC}\left(n\right)-\mathrm{IA}\left(n\right)}{2I_0\sin (15\mathrm{\&pi;}/16)},$ φ _sag1(n)∈[-23π/16，-7π/16)

${\mathrm{\&phi;}}_{\mathrm{sag}2}\left(n\right)={\sin }^{-1}\frac{\mathrm{ID}\left(n\right)-\mathrm{IB}\left(n\right)}{2I_0},$ φ _sag2(n)∈[-π/2，-π/2) (6)

${\mathrm{\&phi;}}_{\mathrm{sag}3}\left(n\right)=+\frac{15\mathrm{\&pi;}}{16}+{\sin }^{-1}\frac{\mathrm{IE}\left(n\right)-\mathrm{IC}\left(n\right)}{2I_0\sin (15\mathrm{\&pi;}/16)},$ φ _sag3(n)∈[7π/16，23π/16)

Demodulation result φ according to the last demodulation cycle _Sag(n-1), determine φ _Sag(n) resolve the interval be a left side interval [23 π/16～-7 π/16) or middle interval [pi/2～pi/2) or right interval [7 π/16～23 π/16), select then to resolve the result accordingly, then can expand the actual angular velocity that can measure.And according to (5) and (6) formula also as can be known, have common interval respectively between between adjacent region as left interval and middle interval, middle interval and right interval, common interval [pi/2～-7 π/16) resolve formula φ _Sag1(n) and φ _Sag2(n), common interval [pi/2～-7 π/16) resolve formula φ _Sag2(n) and φ _Sag3(n), two in common interval is resolved resolving of formula and is come to the same thing, the effect of smith trigger is played in common interval, the match lattice Neck phase shift that is used to avoid angular velocity to produce is in frequent switching of interval boundary and resolves the interval, make system under high acceleration, resolve the interval and do not need frequent variations, reduce the reliability of calculated amount and raising system.

It is as follows specifically to resolve interval system of selection: if φ _Sag(n-1) not in common interval, then according to φ _Sag(n-1) actual size selects to resolve interval be left interval, middle interval or right interval; If in the common interval, φ then _Sag(n) φ is continued to use in the interval of resolving _Sag(n-1) resolve the interval.Also be that selection course is a recursive procedure, the recurrence initial value is determined by the system boot initialize routine.To the optical fibre gyro that starts in stationary state, initially resolve the interval middle interval that is, this is the startup situation of most systems.

Determine φ _SagResolving (n) is interval back by resolving interval corresponding φ _Sag(n) the formula of resolving is resolved, with φ _Sag(n) monotony interval expand to [23 π/16～23 π/16), than original monotony interval [pi/2～pi/2) expanded 23/8 times, near 3 times, but be equivalent to the dynamic range expansion of optical fibre gyro measured angular speed 23/8 times.

The step of the technical solution adopted in the present invention is as follows:

In a modulation cycle, by a fixing phase modulated signal optical fibre gyro is carried out phase modulation (PM), obtain the gyro output signal size in different modulating step in this modulation cycle simultaneously by the sample circuit sampling of optical fibre gyro; Selected the correct interval of resolving by the demodulation result recurrence in a last modulation cycle, resolve the match lattice Neck phase shift that obtains this modulation cycle inner fiber gyro according to selecting to resolve interval solution formula, and obtain the angular velocity of system, realize the expansion of divided ring optical fiber gyroscope dynamic range.

Described phase modulated signal is made up of five different modulation step A, B, C, D and E, the phase modulation (PM) amplitude of these five modulation steps is-7 π/8 in turn,-pi/2,0 ,+pi/2 ,+7 π/8, the duration of each modulation step is the transit time τ of optical fibre gyro, optical fibre gyro corresponding output signal under each modulation step is designated as IA (n), IB (n), IC (n), ID (n) and IE (n) respectively, and n is an integer, the sequence number in expression modulation cycle.

Output signal IA (n), IB (n), IC (n), ID (n) and the IE (n) of the optical fibre gyro in described different modulating step, the interval of resolving of optical fibre gyro is divided into three and resolves the interval, be respectively: a left side interval [23 π/16～-7 π/16), middle interval [pi/2～pi/2) and right interval [7 π/16～23 π/16), there is common interval in the wherein adjacent interval of resolving, a left side interval and middle interval have common interval [pi/2～-7 π/16), middle interval and right interval have common interval [7 π/16～pi/2); Three are resolved and resolve the result in the interval separately and be designated as φ _Sag1(n), φ _Sag2(n), φ _Sag3(n), it is as follows respectively to resolve formula, wherein I ₀Mean value for the optical fibre gyro system output signal:

${\mathrm{\&phi;}}_{\mathrm{sag}1}\left(n\right)=-\frac{15\mathrm{\&pi;}}{16}+{\sin }^{-1}\frac{\mathrm{IC}\left(n\right)-\mathrm{IA}\left(n\right)}{2I_0\sin (15\mathrm{\&pi;}/16)},$ φ _sag1(n)∈[-23π/16，-7π/16)

${\mathrm{\&phi;}}_{\mathrm{sag}2}\left(n\right)={\sin }^{-1}\frac{\mathrm{ID}\left(n\right)-\mathrm{IB}\left(n\right)}{2I_0},$ φ _sag2(n)∈[-π/2，-π/2)

${\mathrm{\&phi;}}_{\mathrm{sag}3}\left(n\right)=+\frac{15\mathrm{\&pi;}}{16}+{\sin }^{-1}\frac{\mathrm{IE}\left(n\right)-\mathrm{IC}\left(n\right)}{2I_0\sin (15\mathrm{\&pi;}/16)},$ φ _sag3(n)∈[7π/16，23π/16)

Described common interval has two to resolve formula, common interval [pi/2～-7 π/16) resolve formula φ _Sag1(n) and φ _Sag2(n), common interval [pi/2～-7 π/16) resolve formula φ _Sag2(n) and φ _Sag3(n), common interval two are resolved resolving of formula and come to the same thing; Smith trigger is played in common interval, and the match lattice Neck phase shift that can avoid angular velocity to produce is resolved the interval frequent switching of the interval boundary of clearing, makes system not needing frequent the switching to resolve the interval under the angular acceleration greatly, reduces calculated amount and improves reliability.

Described to resolve interval system of selection specific as follows: optical fibre gyro is resolved φ as a result _Sag(n) resolve the interval recursive procedure that is chosen as, if the demodulation result φ in last modulation cycle _Sag(n-1) not in common interval, then according to φ _Sag(n-1) actual size is selected to resolve interval and solution formula, works as φ _Sag(n-1) ∈ [23 π/16 ,-7 π/16) choose φ _Sag1(n) resolve formula, work as φ _Sag(n-1) ∈ [pi/2 ,-pi/2) time choose φ _Sag2(n) resolve formula, work as φ _Sag(n) ∈ [7 π/16,23 π/16) time choose φ _Sag3(n) resolve formula; If φ _Sag(n-1) in common interval, φ then _Sag(n) φ is continued to use in the interval of resolving _Sag(n-1) resolve the interval; Determine by the system boot initialize routine and resolve interval initial value; For the optical fibre gyro that starts in stationary state, the initial interval of resolving is middle interval.

The expansion of described divided ring optical fiber gyroscope dynamic range need not changed system hardware, is original 23/8 times with its testable angular velocity dynamic range expansion on original optical fibre gyro basis.

The beneficial effect that the present invention has is:

A kind of expanding open loop optical fiber gyroscope dynamic approach is proposed first, by optical fibre gyro being carried out periodic many modulation steps phase modulation (PM), select the different intervals of resolving by recursion method, optical fiber gyroscope dynamic range is expanded to original 23/8 times, make 100 meters of fiber optic loop degree, diameter is 0.06 meter, optical source wavelength is that the dynamic range of 0.85 micron fiber gyro is from [+600 °/second,-600 °/second] expand to [+1725 °/second,-1725 °/second], thereby satisfying high maneuverability motion carrier needs accurately measures up to thousands of °/requirement of the angular velocity of second-time, and this method need not changed hardware, improve the performance of optical fibre gyro, had high practical value.

Description of drawings

Fig. 1 is the modulation signal and the corresponding output signal of open-loop optical fiber gyro.

Fig. 2 is the process flow diagram of dynamic range expanded optical fibre gyro signal Processing.

Embodiment

The invention will be further described below in conjunction with drawings and Examples:

Fig. 1 is the modulation signal and the corresponding output signal of open-loop optical fiber gyro, the periodic phase modulation signal that curve 1 is subjected to for optical fibre gyro among the figure, the output signal when Fig. 2 is the optical fibre gyro stationary state under modulation signal 1.Modulation signal 1 is a periodic signal, 5 modulation steps in the one-period, i.e. modulation step A, B, C, D and E among the figure, the duration of each modulation step is the transit time τ of one times of optical fibre gyro, thus i.e. 5 τ of the transit time that an actual modulation cycle is five times of optical fibre gyros.The phase modulation (PM) amplitude of five modulation steps has nothing in common with each other, and is respectively-7 π/8 ,-pi/2,0 ,+pi/2 ,+7 π/8 according to the order of A, B, C, D, E.

Optical Fiber Gyroscope 2 is the output corresponding to the open-loop optical fiber gyro of modulation signal 1, for five different modulation step A, B, C, D and E, its corresponding output signal is respectively IA, IB, IC, ID and IE, the output signal in five different modulating steps of actual optical fibre gyro obtains by the digital simulation sample circuit sampling of gyro, can be designated as IA (n), IB (n), IC (n), ID (n) and IE (n) to output signal respectively corresponding to the different modulation cycles, wherein n is a positive integer, the sequence number in expression modulation cycle.

Fig. 2 is the process flow diagram of dynamic range expanded optical fibre gyro signal Processing, wherein 3 is sample circuits of optical fibre gyro, it carries out digital analogue signal by the signal to optical fibre gyro output and is converted to digital signal IA (n), IB (n), IC (n), ID (n) and IE (n), and output to dynamic range expanded resolving in the module 13, and dynamic range expanded resolve in the module 13 realize the dynamic range expanded demodulation of optical fibre gyro after, angular velocity information is outputed to communication module 8 offers application system and use.The dynamic range expanded module 13 of resolving is sent to three parallel operator module 4,5,6 of separating behind the open loop gyro signal that receives from sample circuit 3, in separating operator module 4,5,6, realize the resolving of match lattice Neck phase place of different monotony intervals, separate operator module 4,5,6 and independently resolve separately by following formula according to signal and obtain matching the phase shift of lattice Neck from sample circuit 3:

${\mathrm{\&phi;}}_{\mathrm{sag}1}\left(n\right)=-\frac{15\mathrm{\&pi;}}{16}+{\sin }^{-1}\frac{\mathrm{IC}\left(n\right)-\mathrm{IA}\left(n\right)}{2I_0\sin (15\mathrm{\&pi;}/16)},$ φ _sag1(n)∈[-23π/16，-7π/16)

${\mathrm{\&phi;}}_{\mathrm{sag}2}\left(n\right)={\sin }^{-1}\frac{\mathrm{ID}\left(n\right)-\mathrm{IB}\left(n\right)}{2I_0},$ φ _sag2(n)∈[-π/2，-π/2)

${\mathrm{\&phi;}}_{\mathrm{sag}3}\left(n\right)=+\frac{15\mathrm{\&pi;}}{16}+{\sin }^{-1}\frac{\mathrm{IE}\left(n\right)-\mathrm{IC}\left(n\right)}{2I_0\sin (15\mathrm{\&pi;}/16)},$ φ _sag3(n)∈[7π/16，23π/16)

Separating operator module 4,5,6 will resolve the result and be input in multiplier 9,10 and 11 after independently resolving separately, what multiplier 9,10 and an in addition input signal of 11 derived from that module resolves interval selection device 7 resolves interval selection signal S1, S2, S3, resolve interval selection signal S1, S2, S3 produces by resolving interval selection device 7, wherein has only one to be 1; Multiplier 9,10 and 11 output signal are input in the totalizer 12; Because S1, S2 has only one to be 1 among the S3, thus totalizer be output as corresponding with resolve interval selection signal S1, S2 is the output of 1 multiplier among the S3, also promptly exports φ _Sag(n) be: φ _Sag(n)=S1* φ _Sag1(n)+S2* φ _Sag2(n)+S3* φ _Sag3(n).The output φ of totalizer 12 _Sag(n) promptly be proportional to the match lattice Neck phase shift of system's rotational angular velocity, this phase shift passed out to communication module 8 offer application system.Totalizer also outputs to the output phase shift in this modulation cycle simultaneously and resolves interval selection device 7, is produced according to following principle by it and resolves interval selection signal S1, S2, S3: if the demodulation in last demodulation cycle output φ _Sag(n-1) scope [23 π/16～-pi/2), then resolve interval selection signal S1, S2, S3 are 1,0,0, output from the output φ that resolves unit 4 _Sag1(n); If the demodulation in last demodulation cycle output φ _Sag(n-1) scope [pi/2～pi/2) then resolve interval selection signal S1, S2, S3 are 1,0,0, output from the output φ that resolves unit 5 _Sag2(n); If the demodulation in last demodulation cycle output φ _Sag(n-1), [pi/2～23 π/16) then resolve interval selection signal S1, S2, S3 are 0,0,1, output is from the output φ that resolves unit 6 _Sag3(n); If last demodulation cycle demodulation output φ _Sag(n-1) in common interval, then continue to use the formula of resolving in a modulation cycle.By such method with the dynamic range of optical fibre gyro from original [pi/2～pi/2) expand to [23 π/16～23 π/16).

Output signal IA (n), IB (n), IC (n), ID (n) and IE (n) according to the optical fibre gyro in described different modulating step, the interval of resolving of optical fibre gyro is divided into three and resolves the interval, be respectively: a left side interval [23 π/16～-7 π/16), middle interval [pi/2～pi/2) and right interval [7 π/16～23 π/16), there is common interval in the wherein adjacent interval of resolving, a left side interval and middle interval have common interval [pi/2～-7 π/16), middle interval and right interval have common interval [7 π/16～pi/2); Three are resolved and resolve the result in the interval separately and be designated as φ _Sag1(n), φ _Sag2(n), φ _Sag3(n), the difference formula that resolves is as follows, wherein I ₀Mean value for the optical fibre gyro system output signal:

${\mathrm{\&phi;}}_{\mathrm{sag}1}\left(n\right)=-\frac{15\mathrm{\&pi;}}{16}+{\sin }^{-1}\frac{\mathrm{IC}\left(n\right)-\mathrm{IA}\left(n\right)}{2I_0\sin (15\mathrm{\&pi;}/16)},$ φ _sag1(n)∈[-23π/16，-7π/16)

${\mathrm{\&phi;}}_{\mathrm{sag}2}\left(n\right)={\sin }^{-1}\frac{\mathrm{ID}\left(n\right)-\mathrm{IB}\left(n\right)}{2I_0},$ φ _sag2(n)∈[-π/2，-π/2)

${\mathrm{\&phi;}}_{\mathrm{sag}3}\left(n\right)=+\frac{15\mathrm{\&pi;}}{16}+{\sin }^{-1}\frac{\mathrm{IE}\left(n\right)-\mathrm{IC}\left(n\right)}{2I_0\sin (15\mathrm{\&pi;}/16)},$ φ _sag3(n)∈[7π/16，23π/16)

Common interval has two to resolve formula, common interval [pi/2～-7 π/16) resolve formula φ _Sag1(n) and φ _Sag2(n), common interval [pi/2～-7 π/16) resolve formula φ _Sag2(n) and φ _Sag3(n), common interval two are resolved resolving of formula and come to the same thing; Smith trigger is played in common interval, and the match lattice Neck phase shift that can avoid angular velocity to produce is resolved the interval frequent switching of the interval boundary of clearing, makes system not needing frequent the switching to resolve the interval under the angular acceleration greatly, reduces calculated amount and improves reliability.

It is specific as follows to resolve interval system of selection: optical fibre gyro is resolved φ as a result _Sag(n) resolve the interval recursive procedure that is chosen as, if the demodulation result φ in last modulation cycle _Sag(n-1) not in common interval, then according to φ _Sag(n-1) actual size is selected to resolve interval and solution formula, works as φ _Sag(n-1) ∈ [23 π/16 ,-7 π/16) choose φ _Sag1(n) resolve formula, work as φ _Sag(n-1) ∈ [pi/2 ,-pi/2) time choose φ _Sag2(n) resolve formula, work as φ _Sag(n) ∈ [7 π/16,23 π/16) time choose φ _Sag3(n) resolve formula; If φ _Sag(n-1) in common interval, φ then _Sag(n) φ is continued to use in the interval of resolving _Sag(n-1) resolve the interval; Determine by the system boot initialize routine and resolve interval initial value; For the optical fibre gyro that starts in stationary state, the initial interval of resolving is middle interval.

The method of the dynamic range of described expanding optical fibre gyroscope angular velocity measurement need not changed system hardware, is original 23/8 times with the testable angular velocity dynamic range expansion of optical fibre gyro on original hardware foundation.

Claims (2)

1, the method for expanding open loop optical fiber gyroscope dynamic range, in a modulation cycle, by a fixing phase modulated signal optical fibre gyro is carried out phase modulation (PM), obtain the gyro output signal size in different modulating step in this modulation cycle simultaneously by the sample circuit sampling of optical fibre gyro; Selected the correct interval of resolving by the demodulation result recurrence in a last modulation cycle, resolve the match lattice Neck phase shift that obtains this modulation cycle inner fiber gyro according to selecting to resolve interval solution formula, and obtain the angular velocity of system, realize the expansion of divided ring optical fiber gyroscope dynamic range; It is characterized in that:

Described phase modulated signal is made up of five different modulation step A, B, C, D and E, the phase modulation (PM) amplitude of these five modulation steps is-7 π/8 in turn,-pi/2,0 ,+pi/2 ,+7 π/8, the duration of each modulation step is the transit time τ of optical fibre gyro, optical fibre gyro corresponding output signal under each modulation step is designated as IA (n), IB (n), IC (n), ID (n) and IE (n) respectively, and n is an integer, the sequence number in expression modulation cycle; Output signal IA (n), IB (n), IC (n), ID (n) and the IE (n) of the optical fibre gyro in described different modulating step, the interval of resolving of optical fibre gyro is divided into three and resolves the interval, be respectively: a left side interval [23 π/16～-7 π/16), middle interval [pi/2～pi/2) and right interval [7 π/16～23 π/16), there is common interval in the wherein adjacent interval of resolving, a left side interval and middle interval have common interval [pi/2～-7 π/16), middle interval and right interval have common interval [7 π/16～pi/2); Three are resolved and resolve the result in the interval separately and be designated as φ _Sag1(n), φ _Sag2(n), φ _Sag3(n), it is as follows respectively to resolve formula, wherein I ₀Mean value for the optical fibre gyro system output signal:

${\mathrm{\&phi;}}_{\mathrm{sag}1}\left(n\right)=-\frac{15\mathrm{\&pi;}}{16}+{\sin }^{-1}\frac{\mathrm{IC}\left(n\right)-\mathrm{IA}\left(n\right)}{2I_0\sin (15\mathrm{\&pi;}/16)},$ φ _sag1(n)∈[-23π/16，-7π/16)

${\mathrm{\&phi;}}_{\mathrm{sag}2}\left(n\right)={\sin }^{-1}\frac{\mathrm{ID}\left(n\right)-\mathrm{IB}\left(n\right)}{2I_0},$ φ _sag2(n)∈[-π/2，+π/2)

${\mathrm{\&phi;}}_{\mathrm{sag}3}\left(n\right)=+\frac{15\mathrm{\&pi;}}{16}+{\sin }^{-1}\frac{\mathrm{IE}\left(n\right)-\mathrm{IC}\left(n\right)}{2I_0\sin (15\mathrm{\&pi;}/16)},$ φ _sag3(n)∈[7π/16，23π/16)；

Described common interval has two to resolve formula, common interval [pi/2～-7 π/16) resolve formula φ _Sag1(n) and φ _Sag2(n); Common interval [+7 π/16～+ pi/2) resolve formula φ _Sag2(n) and φ _Sag3(n), common interval two are resolved resolving of formula and come to the same thing; Common interval play smith trigger, avoid match lattice Neck phase shift that angular velocity produces to resolve the interval resolving frequent switching of interval boundary, make system under big angular acceleration, not need frequent the switching to resolve the interval, reduce calculated amount and raising reliability;

Described to resolve interval system of selection specific as follows: optical fibre gyro is resolved φ as a result _Sag(n) resolve the interval recursive procedure that is chosen as, if the demodulation result φ in last modulation cycle _Sag(n-1) not in common interval, then according to φ _Sag(n-1) actual size is selected to resolve interval and solution formula, works as φ _Sag(n-1) ∈ [23 π/16 ,-7 π/16) choose φ _Sag1(n) resolve formula, work as φ _Sag(n-1) ∈ [pi/2 ,+pi/2) time choose φ _Sag2(n) resolve formula, work as φ _Sag(n) ∈ [7 π/16,23 π/16) time choose φ _Sag3(n) resolve formula; If φ _Sag(n-1) in common interval, φ then _Sag(n) φ is continued to use in the interval of resolving _Sag(n-1) resolve the interval; Determine by the system boot initialize routine and resolve interval initial value; For the optical fibre gyro that starts in stationary state, the initial interval of resolving is middle interval.

2, the method for expanding open loop optical fiber gyroscope dynamic range according to claim 1, it is characterized in that: the expansion of described divided ring optical fiber gyroscope dynamic range, need not change system hardware, be original 23/8 times with its testable angular velocity dynamic range expansion on original optical fibre gyro basis.

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