CN101187559A

CN101187559A - Method of Extending Dynamic Range of Open-loop Fiber Optic Gyroscope

Info

Publication number: CN101187559A
Application number: CNA200710160367XA
Authority: CN
Inventors: 陈杏藩; 刘承; 舒晓武; 牟旭东; 胡慧珠
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2007-12-18
Filing date: 2007-12-18
Publication date: 2008-05-28
Anticipated expiration: 2027-12-18
Also published as: CN100580377C

Abstract

本发明公开了一种扩展开环光纤陀螺动态范围的方法。通过对开环光纤陀螺进行周期性的相位调制，相位调制信号包含调制幅度各异、持续时间为开环光纤陀螺渡越时间的五个调制步；由采样电路获得这五个调制步对应的系统信号输出，选取正确的解算区间的解算算法进行解算，得到系统经动态范围扩展后的赛格奈克相位；解算区间的选取根据上一调制周期解调得的赛格奈克相位，利用递归的方法进行，并在相邻的解算区间中引入了共同区间，在扩展光纤陀螺动态范围的同时提高光纤陀螺的可靠性；该方法不需改动硬件，即将开环光纤陀螺的动态范围扩展为原有的23/8倍，能够测试高于1000°/秒的角速度，提高了其测试的范围，具有很高的实用价值。The invention discloses a method for expanding the dynamic range of an open-loop fiber optic gyroscope. Through the periodic phase modulation of the open-loop fiber optic gyroscope, the phase modulation signal contains five modulation steps with different modulation amplitudes and the duration is the transit time of the open-loop fiber optic gyroscope; the system corresponding to the five modulation steps is obtained by the sampling circuit Signal output, select the correct calculation interval calculation algorithm for calculation, and obtain the SegNeck phase after the system has been expanded by the dynamic range; the selection of the solution interval is based on the SegNeck phase demodulated in the previous modulation cycle , using a recursive method, and introducing a common interval in the adjacent solution intervals, while expanding the dynamic range of the fiber optic gyroscope and improving the reliability of the fiber optic gyroscope; this method does not need to change the hardware, the dynamic The range is expanded to 23/8 times of the original, and it can test the angular velocity higher than 1000°/s, which improves the test range and has high practical value.

Description

Method of Extending Dynamic Range of Open-loop Fiber Optic Gyroscope

技术领域technical field

本发明涉及光纤陀螺传感器中的信号处理方法，尤其是涉及一种扩展开环光纤陀螺动态范围的方法。The invention relates to a signal processing method in an optical fiber gyroscope sensor, in particular to a method for expanding the dynamic range of an open-loop optical fiber gyroscope.

背景技术Background technique

光纤陀螺是一种新型的角速度测量仪，其工作原理是基于光学赛格奈克效应的光纤干涉仪，即当环形干涉仪旋转时，产生一个正比于旋转角速度的相位差，通过检测该相位差，即可得到环形干涉仪所在系统的角速度。由于光纤陀螺具有全固态、带宽大及具有多种协议数字输出的优点，被广泛的用于导航和姿态控制系统中。The fiber optic gyroscope is a new type of angular velocity measuring instrument. Its working principle is a fiber optic interferometer based on the optical Segneck effect, that is, when the ring interferometer rotates, a phase difference proportional to the rotational angular velocity is generated. By detecting the phase difference , the angular velocity of the system where the ring interferometer is located can be obtained. Fiber optic gyroscopes are widely used in navigation and attitude control systems due to their advantages of solid state, wide bandwidth and digital output with multiple protocols.

光纤陀螺的本征响应函数为余弦函数，但为了改善光纤陀螺输出信号的线性度和灵敏度，一般对光纤陀螺进行方波调制，使其工作在最灵敏的±π/2的相位偏置上，此时光纤陀螺的输出可表示为。The eigenresponse function of the fiber optic gyroscope is a cosine function, but in order to improve the linearity and sensitivity of the output signal of the fiber optic gyroscope, the square wave modulation is generally performed on the fiber optic gyroscope to make it work at the most sensitive ±π/2 phase offset, At this time, the output of the fiber optic gyroscope can be expressed as.

其中I₀为系统平均输出信号，I为系统实际的输出信号，φ_Sag为转动产生的赛格奈克相移，±π/2为动态相位偏置。通过对光纤陀螺输出信号的解调可得到赛格奈克相移的大小，而赛格奈克相移和角速度的关系可以表示如下：Among them, I ₀ is the average output signal of the system, I is the actual output signal of the system, φ _Sag is the Segneck phase shift generated by rotation, and ±π/2 is the dynamic phase offset. The magnitude of the Segneck phase shift can be obtained by demodulating the output signal of the fiber optic gyroscope, and the relationship between the Segneck phase shift and the angular velocity can be expressed as follows:

${φ φ}_{Sag Sag} = = \frac{22 πLD πLD}{λc λc} Ω Ω - - - - - - ((22))$

其中L为光纤陀螺光纤环光纤长度，D为光纤环直径，λ光纤陀螺所用光源波长，c为真空中光速，Ω为系统角速度。Where L is the fiber length of the fiber optic gyroscope, D is the diameter of the fiber optic ring, the wavelength of the light source used by the lambda fiber optic gyroscope, c is the speed of light in vacuum, and Ω is the angular velocity of the system.

光纤陀螺的动态范围指光纤陀螺能够测量的角速度的范围，由于光纤陀螺本征响应函数为余弦函数，其单调区间范围为π，该单调区间对应的角速度范围即为光纤陀螺的动态范围。动态相位偏置下动态范围为对应于[-π/2，π/2)相位的角速度范围，根据(2)可计算动态范围范围为 $Ω &Element; [- \frac{λc}{4 L D}, + \frac{λc}{4 LD}) .$ The dynamic range of the fiber optic gyroscope refers to the range of angular velocity that the fiber optic gyroscope can measure. Since the eigenresponse function of the fiber optic gyroscope is a cosine function, its monotonic range is π, and the angular velocity range corresponding to the monotonic range is the dynamic range of the fiber optic gyroscope. The dynamic range under dynamic phase bias is the angular velocity range corresponding to the [-π/2, π/2) phase, and the dynamic range can be calculated according to (2) as $Ω &Element; [- \frac{λc}{4 L D.}, + \frac{λc}{4 LD}) .$

动态范围和所用光纤环光纤长度L和直径D的积成反比，对于光纤环长度为1千米，直径为0.1米，光源波长为0.85微米的典型高精度光纤陀螺，动态范围为[-36°/秒，36°/秒]，对于光纤环长度为100米，直径为0.06米，光源波长为0.85微米的中低精度光纤陀螺，动态范围为[-600°/秒，600°/秒]。若需要更大的动态范围，则需要减小光纤长度或者光纤环直径，但过小的光纤环直径会造成系统弯曲损耗增大和信噪比降低，削弱光纤陀螺输出角速度信号的精度；而更短的光纤长度要求更快速的调制解调速度，要求后续处理电路解算能力更强大，增大电路硬件系统的复杂度和难度，引入更多电磁耦合，造成了潜在死区的增大。The dynamic range is inversely proportional to the product of the fiber length L and the diameter D of the optical fiber ring used. For a typical high-precision fiber optic gyroscope with a fiber ring length of 1 km, a diameter of 0.1 m, and a light source wavelength of 0.85 microns, the dynamic range is [-36° /sec, 36°/sec], for medium and low-precision fiber optic gyroscopes with a fiber ring length of 100 meters, a diameter of 0.06 meters, and a light source wavelength of 0.85 microns, the dynamic range is [-600°/sec, 600°/sec]. If a larger dynamic range is required, the length of the fiber or the diameter of the fiber ring needs to be reduced, but too small a fiber ring diameter will cause an increase in system bending loss and a decrease in the signal-to-noise ratio, which will weaken the accuracy of the output angular velocity signal of the fiber optic gyroscope; The length of the optical fiber requires faster modulation and demodulation speed, and requires the subsequent processing circuit to be more powerful, which increases the complexity and difficulty of the circuit hardware system, and introduces more electromagnetic coupling, resulting in an increase in the potential dead zone.

可见减小光纤环长度和直径的方法扩大动态范围并不实用，实际上光纤环长度小于100米，直径小于0.06米的光纤陀螺由于技术难度过大而无法实用化，而在某些高机动性运动载体中，测量1000°/秒量级的角速度又是一个现实需求，从而要求能够有一种新的技术方法，能够不增加现有硬件设计难度及降低系统性能，即能扩展光纤陀螺的动态范围，实现对类似数千°/秒量级大角速度的准确此测量，以满足高机动性运动载体的应用需求。It can be seen that it is not practical to expand the dynamic range by reducing the length and diameter of the fiber optic ring. In fact, the fiber optic gyroscope with a length of fiber optic ring less than 100 meters and a diameter of less than 0.06 meters cannot be practical due to technical difficulties. In the motion carrier, measuring the angular velocity of the order of 1000°/s is a realistic demand, which requires a new technical method, which can expand the dynamic range of the fiber optic gyroscope without increasing the difficulty of the existing hardware design and reducing the system performance. , to achieve accurate measurement of large angular velocities on the order of thousands of degrees per second, so as to meet the application requirements of high-mobility motion carriers.

发明内容Contents of the invention

针对目前光纤陀螺研究中，高机动性运动载体需要准确测量高达数千°/秒量级的角速度，而又无实用简单实现方法的现状，本发明的目的在于提供扩展开环光纤陀螺动态范围的方法，在不增加硬件设计难度及降低精度的基础上，实现对大角速度准确测量，以满足高机动性运动载体的应用需求。Aiming at the present situation that in the current research of fiber optic gyroscopes, high-mobility moving carriers need to accurately measure angular velocities up to thousands of degrees per second, and there is no practical and simple implementation method. The method realizes accurate measurement of large angular velocity without increasing the difficulty of hardware design and reducing the precision, so as to meet the application requirements of high-mobility motion carriers.

发明原理：Invention principle:

对光纤陀螺进行多个不同幅度的相位调制，其中包括原有±π/2动态相位偏置，并对在这些相位调制下陀螺的输出信号进行采样，通过合适的数据处理和组合方法，扩展系统的单调区间范围，消除单调区间受限于[-π/2～π/2)而动态范围受限的问题。Perform multiple phase modulations of different amplitudes on the fiber optic gyroscope, including the original ±π/2 dynamic phase offset, and sample the output signals of the gyroscope under these phase modulations, and expand the system through appropriate data processing and combination methods The range of the monotone interval eliminates the problem that the monotone interval is limited by [-π/2～π/2) and the dynamic range is limited.

改变光纤陀螺系统的相位偏置信号，使一个调制解调周期内含有5个调制步，各个调制步的相位调制幅度顺次为：-7π/8，-π/2，0，+π/2，+7π/8，分别标记为A、B、C、D、E调制步，各调制步的持续时间为光纤陀螺的渡越时间τ，也即相位调制信号mod(t)随时间t变化的表达式如下：Change the phase bias signal of the fiber optic gyro system so that there are 5 modulation steps in a modulation and demodulation cycle, and the phase modulation amplitudes of each modulation step are: -7π/8, -π/2, 0, +π/2 , +7π/8, respectively marked as A, B, C, D, E modulation steps, the duration of each modulation step is the transit time τ of the fiber optic gyroscope, that is, the phase modulation signal mod(t) changes with time t The expression is as follows:

$mod mod ((t t)) = = \{\begin{matrix} + + 1515 π π / / 88,, & t t &Element; &Element; [[55 nτ nτ,, 55 nτ nτ + + τ τ)) \\ + + π π / / 22,, & t t &Element; &Element; [[55 nτ nτ + + τ τ,, 55 nτ nτ + + 22 τ τ)) \\ 00,, & t t &Element; &Element; [[55 nτ nτ + + 22 τ τ,, 55 nτ nτ + + 33 τ τ)) \\ - - π π / / 22,, & t t &Element; &Element; [[55 nτ nτ + + 33 τ τ,, 55 nτ nτ + + 44 τ τ)) \\ - - 1515 π π / / 88,, & t t &Element; &Element; [[55 nτ nτ + + 44 τ τ,, 55 nτ nτ + + 55 τ τ)) \end{matrix} - - - - - - ((33))$

其中n为正整数，表示调制解调周期的序号，τ为光纤陀螺的渡越时间。在调制相位信号mod(t)的调制下光纤陀螺的输出信号表示为：Among them, n is a positive integer, indicating the serial number of the modulation and demodulation cycle, and τ is the transit time of the fiber optic gyroscope. Under the modulation of the modulated phase signal mod(t), the output signal of the fiber optic gyroscope is expressed as:

I(t)＝I₀{1+cos[mod(t)+φ_sag]} (4)I(t)＝I ₀ {1+cos[mod(t)+φ _sag ]} (4)

其中I₀为光纤陀螺系统输出信号的平均值，φ_sag为光纤陀螺所在系统角速度所产生的赛格奈克相移。按照五个调制步为一个调制解调周期，通过光纤陀螺的采样电路采集在五个调制步中的信号分别为IA(n)、IB(n)、IC(n)、ID(n)、IE(n)。令O1(n)、O2(n)、O3(n)分别为三组调制步组合输出信号的差函数为：Among them, I ₀ is the average value of the output signal of the fiber optic gyroscope system, and φ _sag is the Segneck phase shift generated by the angular velocity of the system where the fiber optic gyroscope is located. According to five modulation steps as a modulation and demodulation cycle, the signals collected in the five modulation steps by the sampling circuit of the fiber optic gyroscope are IA(n), IB(n), IC(n), ID(n), IE (n). Let O1(n), O2(n), O3(n) be the difference function of the combined output signals of the three groups of modulation steps respectively:

$O o 11 ((n no)) = = IA IA ((n no)) - - IC IC ((n no)) = = {I I}_{00} [[cos cos ((+ + \frac{1515 π π}{88} + + {φ φ}_{sag sag})) - - cos cos (({φ φ}_{sag sag}))]] = = - - 22 {I I}_{00} sin sin ((\frac{1515 π π}{1616})) sin sin (({φ φ}_{sag sag} + + \frac{1515 π π}{1616}))$

O2(n)＝IB(n)-ID(n)＝I₀[cos(π/2+φ_sag)-cos(-π/2+φ_sag)]＝-2I₀ sin(φ_sag) (5)O2(n)＝IB(n)-ID(n)＝I ₀ [cos(π/2+φ _sag )-cos(-π/2+φ _sag )]＝-2I ₀ sin(φ _sag ) (5 )

$O o 33 ((n no)) = = IC IC ((n no)) - - IE IE ((n no)) = = {I I}_{00} [[cos cos (({φ φ}_{sag sag})) - - cos cos ((- - \frac{1515 π π}{88} + + {φ φ}_{sag sag}))]] = = - - 22 {I I}_{00} sin sin ((\frac{1515 π π}{1616})) sin sin (({φ φ}_{sag sag} - - \frac{1515 π π}{1616}))$

可知O1(n)、O2(n)、O3(n)三个函数各自的单调区间分别为：左区间：[-23π/16～-7π/16)，中区间：[-π/2～π/2)，右区间：[7π/16～23π/16)，其中O1(n)、O2(n)有共同区间[-π/2～-7π/16)，O2(n)、O3(n)有共同区间[7π/16～π/2)。也就是根据这三式可以分别解算得到对应于[-23π/16～-7π/16)、[-π/2～π/2)、[7π/16～23π/16)的赛格奈克相位区间的角速度，三者各自的解算的结果φ_sag1(n)、φ_sag2(n)、φ_sag3(n)分别如下：It can be seen that the monotone intervals of the three functions O1(n), O2(n), and O3(n) are: left interval: [-23π/16～-7π/16), middle interval: [-π/2～π /2), right interval: [7π/16～23π/16), where O1(n), O2(n) have a common interval [-π/2～-7π/16), O2(n), O3(n ) have a common interval [7π/16～π/2). That is to say, according to these three formulas, the Segneck corresponding to [-23π/16～-7π/16), [-π/2～π/2), and [7π/16～23π/16) can be obtained respectively. The angular velocity in the phase interval, the results of the three respective solutions φ _sag1 (n), φ _sag2 (n), φ _sag3 (n) are as follows:

$φ_{sag 1} (n) = - \frac{15 π}{16} + \sin^{- 1} \frac{IC (n) - IA (n)}{2 I_{0} \sin (15 π / 16)},$ φ_sag1(n)∈[-23π/16，-7π/16) $φ_{sag 1} (no) = - \frac{15 π}{16} + \sin^{- 1} \frac{IC (no) - IA (no)}{2 I_{0} \sin (15 π / 16)},$ φ _sag1 (n) ∈ [-23π/16, -7π/16)

$φ_{sag 2} (n) = \sin^{- 1} \frac{ID (n) - IB (n)}{2 I_{0}},$ φ_sag2(n)∈[-π/2，-π/2) (6) $φ_{sag 2} (no) = \sin^{- 1} \frac{ID (no) - IB (no)}{2 I_{0}},$ φ _sag2 (n)∈[-π/2,-π/2) (6)

$φ_{sag 3} (n) = + \frac{15 π}{16} + \sin^{- 1} \frac{IE (n) - IC (n)}{2 I_{0} \sin (15 π / 16)},$ φ_sag3(n)∈[7π/16，23 π/16) $φ_{sag 3} (no) = + \frac{15 π}{16} + \sin^{- 1} \frac{IE (no) - IC (no)}{2 I_{0} \sin (15 π / 16)},$ φ _sag3 (n)∈[7π/16, 23π/16)

根据上个解调周期的解调结果φ_sag(n-1)，确定φ_sag(n)的解算区间是左区间[-23π/16～-7π/16)或者中区间[-π/2～π/2)或者是右区间[7π/16～23π/16)，然后选择相应的解算结果，则可扩展实际可以测量的角速度。而根据(5)和(6)式还可知，相邻区间如左区间和中区间、中区间和右区间间分别拥有共同区间，共同区间[-π/2～-7π/16)有解算式子φ_sag1(n)和φ_sag2(n)，共同区间[-π/2～-7π/16)有解算式子φ_sag2(n)和φ_sag3(n)，共同区间两个解算式子的解算结果相同，共同区间起到史密斯触发器的作用，用于避免角速度产生的赛格奈克相移处于在区间分界处频繁切换解算区间，使系统在大加速度下解算区间不需频繁变化，减小计算量和提高系统的可靠性。According to the demodulation result φ _sag (n-1) of the last demodulation cycle, it is determined that the solution interval of φ _sag (n) is the left interval [-23π/16～-7π/16) or the middle interval [-π/2 ~π/2) or the right interval [7π/16～23π/16), and then select the corresponding calculation result, the angular velocity that can be actually measured can be expanded. According to (5) and (6), it can also be known that adjacent intervals such as the left interval and the middle interval, the middle interval and the right interval have a common interval, and the common interval [-π/2～-7π/16) has a solution formula Sub φ _sag1 (n) and φ _sag2 (n), the common interval [-π/2～-7π/16) has solution formulas φ _sag2 (n) and φ _sag3 (n), common interval two solution formulas The solution results are the same, and the common interval acts as a Smith trigger, which is used to prevent the Segneck phase shift generated by the angular velocity from frequently switching the solution interval at the interval boundary, so that the system does not need to frequently solve the interval under high acceleration Changes, reduce the amount of calculation and improve the reliability of the system.

具体解算区间的选择方法如下：若φ_sag(n-1)不在共同区间中，则根据φ_sag(n-1)实际大小选择解算区间为左区间、中区间或右区间；若共同区间中，则φ_sag(n)的解算区间沿用φ_sag(n-1)的解算区间。也即选择过程为递归过程，递归初始值由系统开机初始化程序确定。对在静止状态启动的光纤陀螺，初始解算区间为中区间，这是绝大部分系统的启动情况。The specific calculation interval selection method is as follows: if φ _sag (n-1) is not in the common interval, then select the calculation interval as the left interval, middle interval or right interval according to the actual size of φ _sag (n-1); if the common interval , the calculation interval of φ _sag (n) follows the calculation interval of φ _sag (n-1). That is, the selection process is a recursive process, and the recursive initial value is determined by the system startup initialization program. For the fiber optic gyroscope started in the static state, the initial solution interval is the middle interval, which is the startup situation of most systems.

确定φ_sag(n)的解算区间后按解算区间对应的φ_sag(n)的解算式子解算，将φ_sag(n)的单调区间扩展到[-23π/16～23π/16)，比原来的单调区间[-π/2～π/2)扩展了23/8倍，接近3倍，等效于将光纤陀螺可测量角速度的动态范围扩展了23/8倍。After determining the calculation interval of φ _sag (n), calculate according to the calculation formula of φ _sag (n) corresponding to the calculation interval, and extend the monotone interval of φ _sag (n) to [-23π/16～23π/16) , which is 23/8 times larger than the original monotonic interval [-π/2～π/2), nearly 3 times, which is equivalent to extending the dynamic range of the optical fiber gyroscope's measurable angular velocity by 23/8 times.

本发明所采用的技术方案的步骤如下：The steps of the technical solution adopted in the present invention are as follows:

在一个调制解调周期内，通过一个固定的相位调制信号对光纤陀螺进行相位调制，同时由光纤陀螺的采样电路采样获得该调制解调周期内不同调制步的陀螺输出信号大小；由上一个调制解调周期的解调结果递归选择正确的解算区间，根据选择解算区间的解算公式解算得到这个调制解调周期内光纤陀螺的赛格奈克相移，并得到系统的角速度，实现对开环光纤陀螺动态范围的扩展。In a modulation and demodulation cycle, the phase modulation of the fiber optic gyroscope is carried out through a fixed phase modulation signal, and at the same time, the sampling circuit of the fiber optic gyroscope is used to sample the output signal size of the gyroscope at different modulation steps in the modulation and demodulation cycle; by the previous modulation The demodulation result of the demodulation cycle recursively selects the correct solution interval, and calculates the Segneck phase shift of the fiber optic gyroscope in this modulation and demodulation cycle according to the solution formula of the selected solution interval, and obtains the angular velocity of the system to realize Expansion of the dynamic range of an open-loop fiber optic gyroscope.

所述的相位调制信号由五个不同的调制步A、B、C、D、和E组成，这五个调制步的相位调制幅度顺次为-7π/8，-π/2，0，+π/2，+7π/8，各调制步的持续时间为光纤陀螺的渡越时间τ，光纤陀螺在各个调制步下对应的输出信号分别记为IA(n)、IB(n)、IC(n)、ID(n)、和IE(n)，n为整数，表示调制解调周期的序号。The phase modulation signal is composed of five different modulation steps A, B, C, D, and E, and the phase modulation amplitudes of these five modulation steps are -7π/8, -π/2, 0, + π/2, +7π/8, the duration of each modulation step is the transit time τ of the fiber optic gyroscope, and the corresponding output signals of the fiber optic gyroscope in each modulation step are denoted as IA(n), IB(n), IC( n), ID(n), and IE(n), n is an integer, indicating the serial number of the modulation and demodulation cycle.

所述的不同调制步的光纤陀螺的输出信号IA(n)、IB(n)、IC(n)、ID(n)、和IE(n)，将光纤陀螺的解算区间分为三个解算区间，分别为：左区间[-23π/16～-7π/16)、中区间[-π/2～π/2)及右区间[7π/16～23π/16)，其中相邻解算区间有共同区间，左区间和中区间有共同区间[-π/2～-7π/16)，中区间和右区间有共同区间[7π/16～π/2)；三个解算区间内各自解算结果记为φ_sag1(n)、φ_sag2(n)、φ_sag3(n)，解算式子分别如下所示，其中I₀为光纤陀螺系统输出信号的平均值：The output signals IA(n), IB(n), IC(n), ID(n) and IE(n) of the fiber optic gyroscopes with different modulation steps divide the solution interval of the fiber optic gyroscope into three solutions Calculation intervals, respectively: left interval [-23π/16～-7π/16), middle interval [-π/2～π/2) and right interval [7π/16～23π/16), among which adjacent calculation The intervals have a common interval, the left interval and the middle interval have a common interval [-π/2～-7π/16), the middle interval and the right interval have a common interval [7π/16～π/2); each of the three calculation intervals The calculation results are recorded as φ _sag1 (n), φ _sag2 (n), and φ _sag3 (n), and the calculation formulas are as follows, where I ₀ is the average value of the output signal of the fiber optic gyro system:

$φ_{sag 2} (n) = \sin^{- 1} \frac{ID (n) - IB (n)}{2 I_{0}},$ φ_sag2(n)∈[-π/2，-π/2) $φ_{sag 2} (no) = \sin^{- 1} \frac{ID (no) - IB (no)}{2 I_{0}},$ φ _sag2 (n)∈[-π/2,-π/2)

$φ_{sag 3} (n) = + \frac{15 π}{16} + \sin^{- 1} \frac{IE (n) - IC (n)}{2 I_{0} \sin (15 π / 16)},$ φ_sag3(n)∈[7π/16，23π/16) $φ_{sag 3} (no) = + \frac{15 π}{16} + \sin^{- 1} \frac{IE (no) - IC (no)}{2 I_{0} \sin (15 π / 16)},$ φ _sag3 (n)∈[7π/16, 23π/16)

所述的共同区间有两个解算式子，共同区间[-π/2～-7π/16)有解算式子φ_sag1(n)和φ_sag2(n)，共同区间[-π/2～-7π/16)有解算式子φ_sag2(n)和φ_sag3(n)，共同区间两个解算式子的解算结果相同；共同区间起史密斯触发器的作用，可避免角速度产生的赛格奈克相移在结算区间分界处频繁切换解算区间，使系统在大角加速度下不需频繁切换解算区间，减小计算量和提高可靠性。The common interval has two solution formulas, and the common interval [-π/2～-7π/16) has solution formulas φ _sag1 (n) and φ _sag2 (n), and the common interval [-π/2～- 7π/16) has solution formulas φ _sag2 (n) and φ _sag3 (n), and the solution results of the two solution formulas in the common interval are the same; the common interval plays the role of Smith trigger, which can avoid the Segney generated by angular velocity Gram phase shift frequently switches the calculation interval at the boundary of the settlement interval, so that the system does not need to frequently switch the calculation interval under high angular acceleration, reducing the amount of calculation and improving reliability.

所述的解算区间的选择方法具体如下：光纤陀螺解算结果φ_sag(n)解算区间的选择为递归过程，若上个调制解调周期的解调结果φ_sag(n-1)不在共同区间中，则根据φ_sag(n-1)实际大小选择解算区间及解算公式，当φ_sag(n-1)∈[-23π/16，-7π/16)选取φ_sag1(n)的解算式子，当φ_sag(n-1)∈[-π/2，-π/2)时选取φ_sag2(n)的解算式子，当φ_sag(n)∈[7π/16，23π/16)时选取φ_sag3(n)的解算式子；若φ_sag(n-1)在共同区间中，则φ_sag(n)的解算区间沿用φ_sag(n-1)的解算区间；而解算区间的初始值由系统开机初始化程序确定；对于在静止状态启动的光纤陀螺，初始的解算区间为中区间。The selection method of the described solution interval is specifically as follows: the selection of the fiber optic gyroscope solution result φ _sag (n) solution interval is a recursive process, if the demodulation result φ _sag (n-1) of the last modulation and demodulation cycle is not in In the common interval, the calculation interval and calculation formula are selected according to the actual size of φ _sag (n-1). When φ _sag (n-1)∈[-23π/16, -7π/16) select φ _sag1 (n) When φ _sag (n-1) ∈ [-π/2, -π/2), select the solution formula of φ _sag2 (n), when φ _sag (n) ∈ [7π/16, 23π /16), select the solution formula of φ _sag3 (n); if φ _sag (n-1) is in the common interval, then the solution interval of φ _sag (n) follows the solution interval of φ _sag (n-1) ; while the initial value of the solution interval is determined by the system startup initialization program; for the fiber optic gyroscope started in a static state, the initial solution interval is the middle interval.

所述的对开环光纤陀螺动态范围的扩展，不需改动系统硬件，在原有光纤陀螺基础上将其可测试的角速度动态范围扩展为原来的23/8倍。The expansion of the dynamic range of the open-loop fiber optic gyroscope does not need to change the system hardware, and the dynamic range of the testable angular velocity is extended to 23/8 times of the original on the basis of the original fiber optic gyroscope.

本发明具有的有益效果是：The beneficial effects that the present invention has are:

首次提出一种扩展开环光纤陀螺动态方法，通过对光纤陀螺进行周期性的多调制步相位调制，通过递归方法选择不同的解算区间，将光纤陀螺动态范围扩展为原有的23/8倍，使光纤环程度100米，直径为0.06米，光源波长为0.85微米的光纤陀螺的动态范围从[+600°/秒，-600°/秒]扩展到[+1725°/秒，-1725°/秒]，从而满足高机动性运动载体需要准确测量高达数千°/秒量级的角速度的要求，并且该方法不需改动硬件，提高了光纤陀螺的性能，具有高的实用价值。For the first time, an extended open-loop fiber optic gyroscope dynamic method is proposed. Through periodic multi-step phase modulation of the fiber optic gyroscope, different solution intervals are selected through a recursive method, and the dynamic range of the fiber optic gyroscope is extended to 23/8 times of the original. , so that the fiber optic ring has a degree of 100 meters, a diameter of 0.06 meters, and a fiber optic gyroscope with a light source wavelength of 0.85 microns. The dynamic range extends from [+600°/sec, -600°/sec] to [+1725°/sec, -1725° /sec], so as to meet the high-mobility motion carrier needs to accurately measure the angular velocity of thousands of degrees per second, and this method does not need to change the hardware, improves the performance of the fiber optic gyroscope, and has high practical value.

附图说明Description of drawings

图1是开环光纤陀螺的调制信号和对应的输出信号。Figure 1 is the modulation signal and the corresponding output signal of the open-loop fiber optic gyroscope.

图2是扩展动态范围的光纤陀螺信号处理的流程图。Figure 2 is a flow chart of fiber optic gyroscope signal processing for extended dynamic range.

具体实施方式Detailed ways

下面结合附图和实施例对本发明作进一步说明：Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

图1是开环光纤陀螺的调制信号和对应的输出信号，图中曲线1为光纤陀螺受到的周期相位调制信号，图2是光纤陀螺静止状态时在调制信号1下的输出信号。调制信号1为周期信号，一个周期内5个调制步，即图中的调制步A、B、C、D和E，各个调制步的持续时间为一倍光纤陀螺的渡越时间τ，从而实际一个调制解调周期为五倍光纤陀螺的渡越时间即5τ。五个调制步的相位调制幅度各不相同，按照A、B、C、D、E的顺序分别为-7π/8，-π/2，0，+π/2，+7π/8。Figure 1 is the modulation signal and the corresponding output signal of the open-loop fiber optic gyroscope. Curve 1 in the figure is the periodic phase modulation signal received by the fiber optic gyroscope, and Figure 2 is the output signal of the fiber optic gyroscope under the modulation signal 1 when it is in a static state. The modulation signal 1 is a periodic signal, and there are 5 modulation steps in one cycle, that is, the modulation steps A, B, C, D, and E in the figure. The duration of each modulation step is twice the transit time τ of the fiber optic gyroscope, so that the actual A modulation and demodulation cycle is five times the transit time of the fiber optic gyroscope, that is, 5τ. The phase modulation amplitudes of the five modulation steps are different, and they are -7π/8, -π/2, 0, +π/2, +7π/8 in the order of A, B, C, D, and E, respectively.

光纤陀螺输出信号2是对应于调制信号1的开环光纤陀螺的输出，对于五个不同的调制步A、B、C、D和E，其对应的输出信号分别为IA、IB、IC、ID和IE，实际的光纤陀螺五个不同调制步的输出信号通过陀螺的数字模拟采样电路采样得到，对应于不同的调制解调周期可以把输出信号分别记为IA(n)、IB(n)、IC(n)、ID(n)和IE(n)，其中n为正整数，表示调制解调周期的序号。The fiber optic gyroscope output signal 2 is the output of the open-loop fiber optic gyroscope corresponding to the modulation signal 1. For five different modulation steps A, B, C, D and E, the corresponding output signals are IA, IB, IC, ID and IE, the output signals of five different modulation steps of the actual fiber optic gyroscope are sampled by the digital analog sampling circuit of the gyroscope, and corresponding to different modulation and demodulation cycles, the output signals can be recorded as IA(n), IB(n), IC(n), ID(n) and IE(n), where n is a positive integer, represents the serial number of the modulation and demodulation cycle.

图2是扩展动态范围的光纤陀螺信号处理的流程图，其中3是光纤陀螺的采样电路，其通过对光纤陀螺输出的信号进行数字模拟信号转换为数字信号IA(n)、IB(n)、IC(n)、ID(n)和IE(n)，并输出到扩展动态范围解算模块13中，并在扩展动态范围解算模块13中实现光纤陀螺扩展动态范围的解调后，将角速度信息输出到通信模块8提供给应用系统使用。扩展动态范围解算模块13在接受到来自采样电路3的开环陀螺信号后送入到三个并行解算子模块4、5、6，在解算子模块4、5、6中实现不同单调区间的赛格奈克相位的解算，解算子模块4、5、6根据来自采样电路3的信号按下式各自独立解算得到赛格奈克相移：Fig. 2 is the flow chart of the fiber optic gyroscope signal processing of extended dynamic range, wherein 3 is the sampling circuit of the fiber optic gyroscope, and it converts the signal of the fiber optic gyroscope output into digital signal IA(n), IB(n), IC(n), ID(n) and IE(n), and output in the extended dynamic range calculation module 13, and after realizing the demodulation of the fiber optic gyroscope extended dynamic range in the extended dynamic range calculation module 13, the angular velocity The information is output to the communication module 8 for use by the application system. After receiving the open-loop gyro signal from the sampling circuit 3, the extended dynamic range calculation module 13 sends it to three parallel solution sub-modules 4, 5, 6, and realizes different monotonous For the calculation of the Segnec phase in the interval, the solution sub-modules 4, 5, and 6 independently calculate the Segnec phase shift according to the signal from the sampling circuit 3 according to the following formula:

$φ_{sag 1} (n) = - \frac{15 π}{16} \sin^{- 1} \frac{IC (n) - IA (n)}{2 I_{0} \sin (15 π / 16)},$ φ_sag1(n)∈[-23π/16，-7π/16) $φ_{sag 1} (no) = - \frac{15 π}{16} \sin^{- 1} \frac{IC (no) - IA (no)}{2 I_{0} \sin (15 π / 16)},$ φ _sag1 (n) ∈ [-23π/16, -7π/16)

$φ_{sag 2} (n) = s {in}^{- 1} \frac{ID (n) - IB (n)}{2 I_{0}},$ φ_sag2(n)∈[-π/2，-π/2) $φ_{sag 2} (no) = the s {in}^{- 1} \frac{ID (no) - IB (no)}{2 I_{0}},$ φ _sag2 (n)∈[-π/2,-π/2)

解算子模块4、5、6在各自独立解算后将解算结果输入到乘法器9、10和11中，乘法器9、10和11的另外个输入信号来源于模块解算区间选择器7的解算区间选择信号S1，S2，S3，解算区间选择信号S1，S2，S3由解算区间选择器7产生，其中只有一个为1；乘法器9、10和11的输出信号输入到加法器12中；由于S1，S2，S3中只有一个为1，从而加法器的输出为对应与解算区间选择信号S1，S2，S3中为1的乘法器的输出，也即输出φ_sag(n)为：φ_sag(n)＝S1*φ_sag1(n)+S2*φ_sag2(n)+S3*φ_sag3(n)。加法器12的输出φ_sag(n)即正比于系统转动角速度的赛格奈克相移，将这个相移送出到通信模块8提供给应用系统。加法器同时还将本调制解调周期的输出相移输出到解算区间选择器7，由其按照下面的原则产生解算区间选择信号S1、S2、S3：若上个解调周期的解调输出φ_sag(n-1)范围在[-23π/16～-π/2)，则解算区间选择信号S1，S2，S3为1，0，0，输出来自解算单元4的输出φ_sag1(n)；若上个解调周期的解调输出φ_sag(n-1)范围在[-π/2～π/2)则解算区间选择信号S1，S2，S3为1，0，0，输出来自解算单元5的输出φ_sag2(n)；若上个解调周期的解调输出φ_sag(n-1)，[π/2～23π/16)则解算区间选择信号S1，S2，S3为0，0，1，输出来自解算单元6的输出φ_sag3(n)；若上个解调周期解调输出φ_sag(n-1)在共同区间内，则沿用上一个调制解调周期的解算式子。通过这样的方法将光纤陀螺的动态范围从原来的[-π/2～π/2)扩展到[-23π/16～23π/16)。The solving sub-modules 4, 5 and 6 input the solving results into the multipliers 9, 10 and 11 after independent solving, and another input signal of the multipliers 9, 10 and 11 comes from the module solving interval selector 7's resolution interval selection signal S1, S2, S3, resolution interval selection signal S1, S2, S3 is produced by resolution interval selector 7, wherein only one is 1; the output signals of multipliers 9, 10 and 11 are input to In the adder 12; Since only one is 1 in S1, S2, and S3, the output of the adder is corresponding to the output of the multiplier that is 1 in the solution interval selection signal S1, S2, and S3, that is, the output φ _sag ( n) is: φ _sag (n)=S1*φ _sag1 (n)+S2*φ _sag2 (n)+S3*φ _sag3 (n). The output φ _sag (n) of the adder 12 is the Segneck phase shift proportional to the rotational angular velocity of the system, and this phase shift is sent to the communication module 8 for the application system. The adder also outputs the output phase shift of this modulation and demodulation cycle to the resolution interval selector 7, which generates the resolution interval selection signals S1, S2, and S3 according to the following principles: if the demodulation of the previous demodulation cycle The range of output φ _sag (n-1) is [-23π/16～-π/2), then the solution interval selection signals S1, S2, S3 are 1, 0, 0, and the output φ _sag1 from the solution unit 4 is output (n); if the range of the demodulation output φ _sag (n-1) of the last demodulation cycle is in [-π/2～π/2), then the resolution interval selection signals S1, S2, and S3 are 1, 0, 0 , output the output φ _sag2 (n) from the resolution unit 5; if the demodulation output φ _sag (n-1) of the last demodulation cycle, [π/2～23π/16) then resolve the interval selection signal S1, S2, S3 are 0, 0, 1, and output the output φ _sag3 (n) from the solving unit 6; if the demodulation output φ _sag (n-1) of the previous demodulation cycle is in the common interval, the previous modulation will be used The solution formula of the demodulation period. Through this method, the dynamic range of the fiber optic gyroscope is extended from the original [-π/2～π/2) to [-23π/16～23π/16).

根据所述的不同调制步的光纤陀螺的输出信号IA(n)、IB(n)、IC(n)、ID(n)、和IE(n)，将光纤陀螺的解算区间分为三个解算区间，分别为：左区间[-23π/16～-7π/16)、中区间[-π/2～π/2)及右区间[7π/16～23π/16)，其中相邻解算区间有共同区间，左区间和中区间有共同区间[-π/2～-7π/16)，中区间和右区间有共同区间[7π/16～π/2)；三个解算区间内各自解算结果记为φ_sag1(n)、φ_sag2(n)、φ_sag3(n)，解算的分别公式如下所示，其中I₀为光纤陀螺系统输出信号的平均值：According to the output signals IA(n), IB(n), IC(n), ID(n), and IE(n) of the fiber optic gyroscopes with different modulation steps, the solution interval of the fiber optic gyroscope is divided into three The solution intervals are: left interval [-23π/16～-7π/16), middle interval [-π/2～π/2) and right interval [7π/16～23π/16), among which adjacent solutions The calculation interval has a common interval, the left interval and the middle interval have a common interval [-π/2～-7π/16), the middle interval and the right interval have a common interval [7π/16～π/2); within the three calculation intervals The respective calculation results are denoted as φ _sag1 (n), φ _sag2 (n), and φ _sag3 (n), and the respective formulas of the calculation are as follows, where I ₀ is the average value of the output signal of the fiber optic gyro system:

共同区间有两个解算式子，共同区间[-π/2～-7π/16)有解算式子φ_sag1(n)和φ_sag2(n)，共同区间[-π/2～-7π/16)有解算式子φ_sag2(n)和φ_sag3(n)，共同区间两个解算式子的解算结果相同；共同区间起史密斯触发器的作用，可避免角速度产生的赛格奈克相移在结算区间分界处频繁切换解算区间，使系统在大角加速度下不需频繁切换解算区间，减小计算量和提高可靠性。The common interval has two solution formulas, the common interval [-π/2～-7π/16) has the solution formulas φ _sag1 (n) and φ _sag2 (n), the common interval [-π/2～-7π/16 ) has the solution formulas φ _sag2 (n) and φ _sag3 (n), and the solution results of the two solution formulas in the common interval are the same; the common interval acts as a Smith trigger, which can avoid the Segneck phase shift generated by the angular velocity Frequently switch the calculation interval at the boundary of the settlement interval, so that the system does not need to frequently switch the calculation interval under high angular acceleration, reducing the amount of calculation and improving reliability.

解算区间的选择方法具体如下：光纤陀螺解算结果φ_sag(n)解算区间的选择为递归过程，若上个调制解调周期的解调结果φ_sag(n-1)不在共同区间中，则根据φ_sag(n-1)实际大小选择解算区间及解算公式，当φ_sag(n-1)∈[-23π/16，-7π/16)选取φ_sag1(n)的解算式子，当φ_sag(n-1)∈[-π/2，-π/2)时选取φ_sag2(n)的解算式子，当φ_sag(n)∈[7π/16，23π/16)时选取φ_sag3(n)的解算式子；若φ_sag(n-1)在共同区间中，则φ_sag(n)的解算区间沿用φ_sag(n-1)的解算区间；而解算区间的初始值由系统开机初始化程序确定；对于在静止状态启动的光纤陀螺，初始的解算区间为中区间。The selection method of the solution interval is as follows: the selection of the solution interval of the optical fiber gyroscope solution result φ _sag (n) is a recursive process, if the demodulation result φ _sag (n-1) of the last modulation and demodulation cycle is not in the common interval , then select the solution interval and solution formula according to the actual size of φ _sag (n-1), when φ _sag (n-1)∈[-23π/16, -7π/16) select the solution formula of φ _sag1 (n) When φ _sag (n-1) ∈ [-π/2, -π/2), select the solution formula of φ _sag2 (n), when φ _sag (n) ∈ [7π/16, 23π/16) When φ _sag3 (n) is selected; if φ _sag (n-1) is in the common interval, then the calculation interval of φ _sag (n) follows the calculation interval of φ _sag (n-1); and the solution The initial value of the calculation interval is determined by the system startup initialization program; for the fiber optic gyroscope started in a static state, the initial calculation interval is the middle interval.

所述扩展光纤陀螺角速度测量的动态范围的方法不需改动系统硬件，在原有硬件基础上将光纤陀螺可测试的角速度动态范围扩展为原来的23/8倍。The method for expanding the dynamic range of the optical fiber gyroscope angular velocity measurement does not need to change the system hardware, and on the basis of the original hardware, the testable angular velocity dynamic range of the optical fiber gyroscope is expanded to 23/8 times of the original.

Claims

1. the method for expanding open loop optical fiber gyroscope dynamic range, it is characterized in that: 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.

2. the method for expanding open loop optical fiber gyroscope dynamic range according to claim 1, 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, n is an integer, the sequence number in expression modulation cycle.

3. the method for expanding open loop optical fiber gyroscope dynamic range according to claim 2, it is characterized in that: the output signal IA (n) of the optical fibre gyro in described different modulating step, IB (n), IC (n), ID (n), and IE (n), the interval of resolving of optical fibre gyro is divided into three and resolves the interval, be respectively: interval, a left side [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:

φ_{sag 1} (n) = - \frac{15 π}{16} + \sin^{- 1} \frac{IC (n) - IA (n)}{2 I_{0} \sin (15 π / 16)},

φ _sag1(n)∈[-23π/16，-7π/16)

φ_{sag 2} (n) = \sin^{- 1} \frac{ID (n) - IB (n)}{2 I_{0}},

φ _sag2(n)∈[-π/2，-π/2)

φ_{sag 3} (n) = + \frac{15 π}{16} + \sin^{- 1} \frac{IE (n) - IC (n)}{2 I_{0} \sin (15 π / 16)},

φ _sag3(n)∈[7π/16，23π/16)

4. the method for expanding open loop optical fiber gyroscope dynamic range according to claim 3, it is characterized in that: 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.

5. the method for expanding open loop optical fiber gyroscope dynamic range according to claim 1 is characterized in that: 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.

6. 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.