RU2685795C1 - Method for compensation of slow meander effect on readings of laser gyroscope - Google Patents

Abstract

FIELD: instrument engineering.

SUBSTANCE: invention relates to instrument making and measurement equipment. Essence of the invention is that the method of compensating for the effect of the slow meander on the readings of the laser gyroscope comprises the steps at which the laser gyroscope is subjected to climatic tests and the coefficients of the n-th power of the dependence of the coefficient A(T)_Mode01 are determined from temperature at certain mode, current value of slow meander amplitude SM=A(T)_Mode01⋅S_cur is determined, where S_cur – current value of amplitude of frequency support, which is measured at each cycle of operation of three-axis laser gyroscope, determining current drift indicators Tdsq_x,y,z and magnetic drift Mdsq_x,y,z and determining the rotation angle value per cycle of operation of the laser gyroscope in radians Ω_x,y,z=Kq_x,y,z·(Rasn+SM)-(Tdsq_x,y,z+Mdsq_x,y,z), where Kq_x,y,z is scaling coefficient of laser gyroscope, Rasn is output characteristic of laser gyroscope.

EFFECT: high accuracy of compensating errors in measurement results.

1 cl, 5 dwg

Description

The invention relates to instrumentation and measurement technology and can be used to improve the accuracy of the readings of a laser gyroscope (LH) in the conditions of possible occurrence of dynamic capture zones and temperature changes in the amplitude of the periodic low-frequency stand.

The emergence of dynamic capture zones in LH with a periodic frequency support was first described in [Kuryatov VN, Landa PS, Lariontsev E.G. Frequency characteristics of a ring laser on an oscillating stand // Izv. Universities, Ser. Radio Physics. 1968. ETC. S. 1839].

There is a method of improving the accuracy of the readings of the measuring axes of angular displacement sensors in a laser gyroscope by introducing a substantially lower frequency periodic frequency support, the so-called “slow meander”, which allows, in particular, according to climatic tests of a laser gyroscope, to take into account the effect of temperature effects .

To improve the accuracy of measurements, an “noise” method is also used, according to which, instead of a signal of a slow meander, a desynchronizing noise signal is introduced [Yu. Golyaev, G.I. Telegin, K.A. Tolstenko, S.O. Yaremenko. Random error ring laser with alternating frequency stand and noise desynchronization signal. Laser technology and optoelectronics. 1990, 4 (56), p. 17-23].

The disadvantage of this method is the relatively low accuracy of the measurements, due to the fact that due to the asynchronous noise component of the signal relative to the frequency pedestal signal, an error occurs on each reverse of the mode and on the last cycle of the LG, affecting the resulting accumulated angle.

The closest in technical essence to the proposed is a method according to which, when measuring and processing their results, the effect of a slow meander is compensated by subtracting it as a constant, constant throughout the work of LG [Yu.Yu. Yu. Sausage, M.E. Grushin, V.N. Pots. The nonmagnetic component of the zero displacement of a Zeeman laser gyro. Quantum electronics. 2018, 48 (3), 283-289].

The disadvantage of the closest technical solution is the relatively low accuracy of compensation, due to the fact that when using it, it is impossible to take into account temperature changes in the amplitude of the slow-square wave signal and non-temperature changes in the stand amplitude, for example, when the sensor has run out immediately after starting the laser gyro.

The objective of the invention is to develop a method to improve the accuracy of compensation in the measurement results of errors caused by temperature changes in the amplitude of the signal of the slow meander and non-temperature changes in the amplitude of the stand, for example, when the sensor has run out immediately after starting the laser gyroscope.

The required technical result is to improve the accuracy of error compensation in the measurement results by taking into account temperature changes in the amplitude of the slow meander signal and non-temperature changes in the height of the stand, for example, when the laser gyroscope reads immediately after the gyroscope starts.

The problem is solved, and the required technical result is achieved by the fact that, in the method of compensating for the effect of a slow meander on the readings of the measuring axes of angular displacement sensors in a three-axis laser gyro, the compensation of the effect of a slow meander on the readings of the laser gyro is performed, According to the climatic tests of a laser gyro at a set of temperature values, determine the coefficient A _Mode01 on each mode:

where: MM _cpModa01 is the average value of the slow meander at temperature T on a certain mode, S _cpTModa01 is the average value of the frequency base at temperature T at a certain mode, then, according to the data obtained for the temperature range during climatic tests, the coefficients of the polynomial nth are determined the degree of dependence of the coefficient A (T) _0ModO01 on temperature at a certain mode

A (T) _Mode01 = A _0Mod01 + A _1Mod01 ⋅T + A _2Mod01 ⋅T ² + ... + A _nMod01 ⋅T ⁿ ,

At each step of the laser gyroscope, the current amplitude value of the slow meander MM = A (T) _Mode01 01S _{tech is} determined, where S _tech is the current amplitude value of the frequency base, which is measured on each laser gyro clock cycle, determine the current drift indicators Tdsq _{x, y , z} and magnetic drift Mdsq _{x, y, z} then determine the values of the angle of rotation per laser gyro cycle in radians

Ω _{x, y, z} = Kq _{x, y, z} ⋅ (Rasn + MM) - (Tdsq _{x, y, z} + Mdsq _{x, y, z} ),

where Kq _{x, y, z} is the scale factor of the laser gyroscope, Rasn is the output characteristic of the laser gyroscope.

The drawing shows:

in fig. 1 - signal of a periodic frequency support;

in fig. 2 - signal of a periodic frequency stand with a slow meander;

in fig. 3 - one period of frequency support;

in fig. 4 - accumulated angle (LH operation with a large stick out when using the slow meander compensation method - by subtracting the constant);

in fig. 5 - accumulated angle (LH operation with a large stick out using the proposed method).

The method of compensating for the effect of a slow meander on the readings of a laser gyro is implemented as follows.

Since the frequency of data acquisition of the laser gyroscope is much higher than the frequency of the slow meander, it is necessary to subtract (compensate) the amplitude of the slow meander from the readings of the sensors of the angular displacements of the axes of readings in the LG calculator.

In the analogs of the proposed method for this, the amplitude constant of the slow meander was used, which was subtracted at each step of the LH operation. However, it is not possible to take into account the current temperature changes in the amplitude of the signal of the slow meander and non-temperature changes in the amplitude of the stand, for example, when the sensor has run out immediately after starting the gyroscope.

The proposed method solves this problem, given the true change in the frequency base.

To implement the proposed method, it is necessary to know the true value of the frequency support at each step of reading the readings of the laser gyroscope. To obtain it, the laser gyro calculator uses rotation data for each half-period of switching the frequency base.

FIG. 3 shows one period of frequency support, where are indicated:

F _CW1 - laser gyro readings when rotated clockwise on the first half period of the frequency support;

F _CCW1 - laser gyro readings when rotating counterclockwise on the first half period of the frequency support;

F _CW2 - laser gyro readings when rotated clockwise on the second floor of the frequency base;

F _CCW2 - laser gyro readings during counterclockwise rotation on the second half period of the frequency support.

The true value of the amplitude of the frequency pedestal is determined from the relationship:

S = (F _cw1 -F _ccw1 ) - (F _cw2 -F _ccw2 )

Knowing the true, rotation-independent, amplitude value of the frequency base on each clock cycle, it is possible to take into account the change in the amplitude of the frequency base when correcting the amplitude of the slow meander.

For this, according to the climatic tests of a laser gyro at a set of temperature values, determine the coefficient A _Mode01 on each mode:

Where:

MM _cpModa01 - the average value of the slow meander at temperature T on a certain mode;

S _CPTMod01 - the average value of the frequency base at temperature T in a certain mode.

Then, data obtained at all temperatures during the environmental tests, are the coefficients of the polynomial of degree n-dependence of the coefficient A (T) _Moda01 the temperature at a particular fashion:

A (T) _mod01 = A _0moda01 + A _1moda01 ⋅Т + A ² _Moda01 ⋅Т ² + ... + A ⁿ _Moda01 ⋅Т ⁿ

The obtained coefficients are inserted into the internal long-term memory of the laser gyro calculator and are used to correct the amplitude value of the slow meander.

At each step of the laser gyro, the current value of the amplitude of the slow meander MM is calculated using the formula:

MM = A (T) _Mode01 ⋅S _tech,

Where:

A (T) _Mode01 - coefficient of temperature dependence of the amplitude of the slow meander on the amplitude of the frequency pedestal (due to the low relative to the frequency of data collection, the rate of temperature change, it is not advisable to calculate this coefficient for each step of the program, the calculation is performed once every few seconds);

S _tech - the current value of the amplitude of the frequency pedestal, which is calculated at each step of the triaxial laser gyro (to increase the accuracy of this value, it is advisable to impose a running filter with a window in a few seconds).

Further, the obtained value of MM is used to calculate the value of the rotation angle per cycle of operation of the sensor of angular displacements in radians using the formula:

Ω _{x, y, z} = Kq _{x, y, z} ⋅ (Rasn + MM) - (Tdsq _{x, y, z} + Mdsq _{x, y, z} )

Where:

Kq _{x, y, z} - scale factor of the sensor of angular movements;

MM is the amplitude value of the slow meander, taking into account the sign of the phase of the slow meander;

Rasn - output characteristic of the sensor of angular movements;

Tdsq _{x, y, z} - current drift;

Mdsq _{x, y, z} - magnetic drift.

Thus, the proposed method achieves the required technical result, which is to improve the accuracy of error compensation in the measurement results by taking into account temperature changes in the amplitude of the signal of the slow meander and non-temperature changes in the amplitude of the stand, for example, when the sensor is run out immediately after starting the gyroscope. This is ensured by the fact that, in the proposed method, it is possible to take into account the current change in the amplitude of the frequency pedestal when calculating the amplitude of the slow meander, which makes it possible to more accurately calculate the amplitude of the slow meander when the angular displacement sensors are being watched for several minutes after the triaxial laser gyroscope is activated.

The best result of the proposed method is given for sensors with a large initial overrun of the amplitude of the frequency pedestal. Changes in the amplitude of the frequency stand and, accordingly, the meander in the first 10 minutes of operation in such sensors can exceed 2%. In the prototype method, such changes cannot be corrected, since the constant recorded in the memory of the LG calculator is set as the average value of the slow meander and, accordingly, it is impossible to compensate for the distance with it.

FIG. 4 shows a graph of the accumulated angle for 50 seconds of operation of the laser gyro while compensating for the slow meander by a constant. With an amplitude of a slow meander of 1.5 pulses, a switching frequency of a slow meander of 0.5 Hz and a data acquisition rate of 1 kHz with a residual slow meander of 38 pulses (see FIG. 4), the compensation error of a slow meander is:

FIG. 5 shows a graph of the accumulated angle for 50 seconds of operation of the laser gyroscope in the same climatic conditions while compensating for the slow meander by the proposed method. With an amplitude of a slow meander of 1.5 pulses, a switching frequency of a slow meander of 0.5 Hz and a data acquisition rate of 1 kHz with a residual slow meander of 7 pulses (see FIG. 5), the compensation error of a slow meander is:

Thus, the proposed method allows to reduce the spread of the readings of the laser gyro more than 5 times, thereby increasing its accuracy.

Claims (7)

A way to compensate for the effect of a slow meander on the readings of a laser gyro, which consists in compensating for the effects of a slow meander on the readings of a laser gyroscope, characterized in that they preliminarily perform climatic tests of the laser gyroscope on a set of temperatures and determine the coefficient A of _Mode01 on each mode:

where MM _cpModa01 is the average value of the slow meander at temperature T on a certain mode, S _cpTModa01 is the average value of the frequency base at temperature T at a certain mode, then, according to data obtained for the temperature range during climatic tests, determine the coefficients of the nth degree polynomial coefficient A (T) _Mode01 on the temperature at a certain mode A (T) _Mode01 = A _0Mod01 + A _1Mod01 ⋅T + A _2Mod01 ⋅T ² + ... + A _nMod01 ⋅T ⁿ , At each step of the laser gyroscope, the current value of the amplitude of the slow meander MM = A (T) _Mode01 текS _{tech is} determined, where S _tech is the current value of the amplitude of the frequency base, which is measured on each clock of the laser gyroscope, determine the current drift indicators Tdsq _{x, y , z} and magnetic drift Мdsq _{x, v, z} and determine the values of the angle of rotation per cycle of the sensor of angular displacements in radians Ω _{x, y, z} = Kq _{x, y, z} ⋅ (Rasn + MM) - (Tdsq _x , _{y, z} + Mdsq _{x, y, z} ), where Kq _{x, y, z} is the scale factor of the laser gyroscope, Rasn is the output characteristic of the laser gyroscope.

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