CN109489686B - Method for testing bandwidth and angular resolution of four-frequency differential laser gyroscope - Google Patents
Method for testing bandwidth and angular resolution of four-frequency differential laser gyroscope Download PDFInfo
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Abstract
The invention discloses a method for testing the bandwidth and angular resolution of a four-frequency differential laser gyroscope, which applies a magnetic field to the four-frequency differential laser gyroscope by utilizing the magnetic zero offset of the four-frequency differential laser gyroscope through a broadband magnetic field generating device, simultaneously records output beat pulses, selects the signal type of the magnetic field and the sampling time of the beat pulses according to the measurement requirement, and then processes data to obtain the bandwidth and the resolution.
Description
Technical Field
The invention relates to a bandwidth and angular resolution test of a four-frequency differential laser gyroscope, belonging to the technical field of test.
Background
The laser gyro has the advantages of large dynamic range, no acceleration effect, simple structure and the like, is an ideal element of an inertial system, particularly a strapdown inertial system, and is widely applied to the fields of military affairs and civil use. The principle of a laser gyro is the Sagnac (Sagnac) effect, in which at least one pair of counter-propagating light waves runs within its optical cavity. When the laser gyro rotates around the sensitive axis relative to the inertial space, the frequency of opposite traveling waves is split to form a difference frequency proportional to the rotation rate, so that the rotation information of the laser gyro relative to the inertial space can be obtained by measuring the difference frequency.
Due to the back scattering of the reflector and other reasons, weak coupling can occur to energy between opposite traveling waves in the annular resonant cavity, so that the laser gyro has a locking effect, and a lower rotating speed cannot be measured. The most common method for overcoming the blocking effect is mechanical dithering offset frequency, and the principle is that a mechanical dithering device is used for providing high-frequency small-amplitude angular velocity input, namely 'dithering', for a laser gyro, and then the dithering angular velocity input is deducted from an output signal of the laser gyro by adopting a signal processing technology, so that the actually measured angular velocity is obtained. However, the mechanical shaking device increases the random walk of the laser gyro, reduces the signal bandwidth, and mechanical vibration can generate mechanical interference on other instruments in the inertial system, such as another gyro, an accelerometer, an optical sighting device and the like in the inertial system.
Another widely used scheme for overcoming latch-up is a four-frequency differential technology, which adopts an optical offset frequency method to overcome latch-up and has the advantages of large bandwidth, no mechanical interference and the like. Four traveling wave modes are operated in a resonant cavity of the four-frequency differential laser gyro, and the principle is as follows: frequency splitting of left-hand (LCP) and right-hand (RCP) traveling waves can be achieved using quartz optical rotators or non-planar ring cavities, and non-reciprocal frequency splitting can be created between opposite traveling waves of the same polarization to avoid the latch-up region using Faraday frequency-shifting devices or application of a longitudinal magnetic field to the gain medium. The left-hand polarized pair of traveling waves constitutes a left-hand polarized two-frequency single gyroscope (called a left-hand gyroscope), and the right-hand polarized pair of traveling waves constitutes a right-hand polarized two-frequency single gyroscope (called a right-hand gyroscope).
The gain curve of the four-frequency differential laser gyro is shown in fig. 1, the frequency division between the left-handed gyro and the right-handed gyro is called reciprocal division, and the typical value is hundreds of MHz; the frequency split between the two oppositely running traveling waves of each single gyroscope is called a nonreciprocal split, typically 1 MHz. The four-frequency differential laser gyro at least comprises four modes: the mode frequency for left hand polarization running clockwise is f1Amplitude of A1(ii) a The mode frequency for left hand polarization running counter-clockwise is f2Amplitude of A2(ii) a The mode frequency of the counterclockwise operation of the right-hand polarization is f3Amplitude of A3(ii) a The mode frequency of the clockwise operation of the right-hand polarization is f4Amplitude of A4. The frequency difference between the two modes of the left-handed gyroscope is:
fL＝f2-f1＝F+SΩ
(1)
where F is the Faraday offset frequency, S is the geometric scale factor of the ring cavity, and Ω is the input angular velocity.
The frequency difference between the two modes of the right-handed gyroscope is as follows:
fR＝f4-f3＝F-SΩ
(2)
the photoelectric detection device and the corresponding signal processing circuit are adopted to respectively measure the frequency difference between the two modes of the left-handed gyro and the right-handed gyro and then calculate the difference to obtain the final output difference frequency of the four-frequency differential laser gyro:
fout＝fL-fR＝2SΩ
(3)
namely, the scale factor of the four-frequency differential laser gyro is doubled compared with that of the two-frequency laser gyro;
in fact, the output difference frequency of the four-frequency differential laser gyro is related to the operating point and the magnetic field, [ wang, longxingwu, wangfei, null shift sensitivity of the four-frequency differential laser gyro [ J ]. infrared and laser engineering, 2011,40(9):1758-,
fout＝2SΩ+α(H-H0)(P-P0)
(4)
where α is the proportionality coefficient, H is the effective magnetic field acting on the gain region, P is the working point, H0And P0The two parameters are respectively, and can be regarded as constants when the gyroscope works stably. When Ω is 0, the gyro output difference frequency is called zero offset, and is denoted by b;
as can be seen from the formula (4), the operating point is not P0Otherwise the difference frequency must contain the influence of the magnetic field α can be compared with (P-P) by experiment0) Calibrated to obtain a magnetic difference frequency coefficient K- α (P-P)0) Therefore, the bandwidth and resolution of the four-frequency differential laser gyro can be tested by using the formula (4), and details are given in a specific embodiment;
the output signal of the four-frequency differential laser gyro is in a standard sinusoidal signal form, and a very high resolution and signal bandwidth can be obtained after a signal processing technology is adopted, so that the four-frequency differential laser gyro is very suitable for application of rapid attitude measurement and control, synthetic aperture radar imaging compensation, aerial remote sensing information compensation and the like. In these applications, the angular resolution and bandwidth of the gyroscope are important criteria. Theoretically, the angular resolution of the four-frequency differential laser gyroscope is better than 0.001 angular second, and the bandwidth is larger than 1KHz, but at present, no mature method is available for accurately testing and calibrating the angular resolution and the bandwidth. A report "Raytheon High resolution angular sensors" published by Raytheon corporation in 1981 suggests that a mechanical vibration table is used to measure the angular resolution of a four-frequency differential laser gyro, and since the High resolution measurement of the vibration amplitude is inherently difficult and the bandwidth and resolution of the mechanical vibration are not easy to control, the measurement method based on the mechanical vibration table has limited accuracy and is expensive;
the Allan variance analysis of the test data of the four-frequency differential laser gyro can also obtain a quantity characterization angular resolution theoretically, but because the method assumes the power law of the frequency signal adoption rate and performs data regrouping and accumulation, the evaluation accuracy of the angular resolution of the high-sampling-rate laser gyro is unreliable.
Disclosure of Invention
The invention provides a method for testing the bandwidth and the angular resolution of a four-frequency differential laser gyroscope, which utilizes the principle that the output difference frequency of the four-frequency differential laser gyroscope changes along with an external magnetic field and provides an accurate and reliable equivalent angle variable quantity for the four-frequency differential laser gyroscope through a broadband adjustable magnetic field generating device as a reference standard so as to calculate the bandwidth and the angular resolution;
a four-frequency differential laser gyro bandwidth and angular resolution testing device applies a magnetic field to a gyro to be tested by adopting a broadband adjustable magnetic field generating device, obtains output beat frequency information of the gyro to be tested by a photoelectric conversion and signal processing device, records and processes data by utilizing a computer, obtains the bandwidth and the resolution of the gyro to be tested after processing the data by generating a magnetic field and recording a corresponding pulse sequence, and comprises the following components:
(1) the constant temperature space, in order to reduce the influence of temperature variation to the test result, need arrange the top that awaits measuring in the constant temperature space, the constant temperature space can adopt the incubator that is used for the temperature test experiment specially, also can adopt air conditioning equipment to control by temperature change to the laboratory. The requirement of the constant temperature space is that the fluctuation of the environmental temperature is less than 0.5 ℃ in the whole test process, and the temperature is monitored by a thermometer;
(2) the gyroscope to be tested needs to be placed in the magnetic shield in order to eliminate the influence of an interference magnetic field in the environment on a test result, and the magnetic shield is usually processed into a required mechanical shape by adopting permalloy;
(3) in the vibration isolation device, as can be seen from equation (4), the difference frequency output of the four-frequency differential laser gyro includes an angular velocity, and the angular component of the mechanical vibration causes a change in the difference frequency, which affects the measurement accuracy, so that the gyro to be measured is placed on the vibration isolation platform. The vibration isolation platform can adopt an air floatation optical platform or a sand-buried stable foundation platform;
(4) the broadband adjustable magnetic field generating device is used for generating a stable, high-bandwidth, low-noise and intensity adjustable magnetic field, loading the magnetic field on a gain region of the four-frequency differential laser gyro and generating magnetic difference frequency output as shown in a formula (4). The broadband adjustable magnetic field generating device consists of a current generating device and a conductive coil. The current generating device may employ a current calibration source table (e.g., 5720 manufactured by FLUKE, Inc.). The conductive coil can be wound on the gain area of the gyroscope to be tested, and the gyroscope to be tested can also be placed in the conductive coil. The requirement of the broadband adjustable magnetic field generating device is that the magnetic field noise is lower than one ten-thousandth of the set magnetic field. For the device for generating the magnetic field by electrifying the coil, the current is in direct proportion to the generated magnetic field intensity, so the magnetic field intensity H can be directly expressed by the current amplitude;
(5) the gyroscope to be tested is a four-frequency differential laser gyroscope finished product and is provided with necessary accessories such as a high-voltage power supply, a frequency stabilizing device, a photoelectric conversion and signal processing device, a computer, a test program and the like. The photoelectric conversion and signal processing device is composed of a photoelectric detector and a signal processor, and provides output difference frequency information of the four-frequency differential laser gyro at a certain time interval (update rate). To reduce quantization errors, resolution enhancement techniques are employed in the signal processor [ quote: ring laser enhanced resolution system, us patent 5485273, where square wave pulse resolution is better than 0.001, and a computer and related test programs are used to record and process difference frequency, and the difference frequency data update rate should meet the test requirements;
the broadband adjustable magnetic field generating device, the gyroscope to be tested and the constant temperature space are arranged in the magnetic shielding cover;
the magnetic shield is arranged on the vibration isolation device;
a method for testing the bandwidth and the angular resolution of a four-frequency differential laser gyroscope comprises the following steps:
preparing the testing device, fixing the gyroscope on the vibration isolation platform, electrifying the gyroscope and a computer, starting a testing program, and preheating the device for more than half an hour;
setting the magnetic field strength to H1Recording zero offset b (T) by using a test program of a four-frequency differential laser gyro, taking the acquisition time length as T, and calculating the average zero offset
Then the magnetic field strength is set to H2To find the corresponding average zero offset
The magnetic zero-bias coefficient is calculated as,
2.1, enabling the output magnetic field intensity of the precise broadband magnetic field generating device to be 0, enabling the corresponding current to be 0, and recording the sampling time to be Ts(TsSetting as required, taking a gyroscope with an angle random walk smaller than 0.0005deg/sqrt (h) as an example, when the data output time can be set to 1ms), outputting a zero offset sequence by a four-frequency differential laser gyroscope as b, and recording M points to obtain a data sequence b (n), wherein n is 1,2, …, M;
2.2, following step 2.1, preferably without interruption, changing the output magnetic field strength of the precise broadband magnetic field generating device to H1Corresponding current is I1Recording a sampling time of TsTime-four frequency differential laser gyro difference frequency output sequence, recording M1Point, obtaining data sequence b1(n)，n＝1,2,…,M1. Calculating the change of current from 0 to I according to the previously calibrated magnetic difference frequency coefficient K1The resulting magneto zero-bias change is Δ b1＝K×I1Halving to the sampling time TsHas a magnetic difference frequency of NH＝Δb1/Ts；
2.3, processing data: separately determining the data sequence b (n) and the data sequence b1(n) average value, and the absolute value of the difference is [ mu ]NData sequenceThe standard deviation of the column b (n) is denoted as σN. The angular resolution is
Where S is the scale factor of the gyroscope and has the unit [ °/h]Per Hz;
the sampling time, the number of data, and the like can be taken according to actual needs, but the principle is not changed. Theoretically, the angular resolution can also be obtained by solving the standard deviation of the pulse sequence and then multiplying the standard deviation by the scale factor, and the method provided by the invention has the advantages that more accurate test can be realized, and the angular resolution is measured by using the number of the magnetic pulses as a scale, so that the method is more suitable for the acceptance of users on products provided by suppliers. Since the filtering can reduce the standard deviation of the measured data sequence, the resolution measurement is preferably performed simultaneously with the bandwidth measurement;
the bandwidth measuring method can use a sine function magnetic field or a square wave magnetic field, and firstly takes the sine function magnetic field as an example: the magnetic field generating device sends out a constant-strength sinusoidal magnetic field with frequency from direct current to high-frequency alternating current, simultaneously records a magnetic difference frequency sequence caused by the sinusoidal magnetic field corresponding to each frequency at set sampling time, calculates a change sequence of the magnetic difference frequency amplitude along with the alternating current magnetic field frequency, and can calculate the bandwidth;
generation of H by using broadband precision magnetic field generator1sin (ω t) alternating magnetic field with amplitude H1The angular frequency is ω, which results in a difference frequency of B1sin (ω t). ω increases from 0 up to ωc，(ωcSet according to application requirements) to record the magnetic zero-offset amplitude corresponding to each angular frequency to obtain B1And the curve is an amplitude-frequency response curve of the four-frequency differential laser gyro. Parameters such as 3dB bandwidth can be obtained by utilizing a signal processing technology. Since the amplitude-frequency response only requires a relative change of zero-bias with the frequency of the magnetic field, H does not need to be known1A specific value of (a);
according to the signal processing theory, as long as the response curve of the system to the sinusoidal signal is obtained, the response of the system to all the signals can be obtained, so that the bandwidth of the four-frequency differential laser gyro measured by using the square wave magnetic field is consistent with that of the sinusoidal magnetic field except for slightly different data processing. Therefore, a person skilled in the signal processing knowledge can develop other bandwidth measurement methods based on the method, such as a square wave magnetic field, a delta function magnetic field and the like.
The invention has the technical effects that: the invention provides an accurate and reliable angular resolution and bandwidth measuring method for the four-frequency differential laser gyroscope, which can be used for factory calibration of the angular resolution and the bandwidth of the four-frequency differential laser gyroscope and can also be used for national standard reference of the laser gyroscope.
Drawings
FIG. 1 is a block diagram of a four-frequency differential laser gyroscope;
FIG. 2 is a schematic diagram of a frequency spectrum of a traveling wave in a cavity of a four-frequency differential laser gyroscope;
fig. 3 is a schematic diagram of a bandwidth and resolution measuring device.
Detailed Description
The following detailed description is provided in conjunction with the accompanying drawings:
fig. 1 and fig. 2 are schematic diagrams of a four-frequency differential laser gyro structure and mode distribution on a gain curve thereof. An air inflation and light transmission pipeline is processed on the low expansion cavity 1, four reflectors 5, 6, 7 and 8 are arranged at four corners of the cavity, wherein 7 is an output mirror. Two anodes 2, 3 and one cathode 4 are used to provide gain. The reciprocal frequency offset element is realized by a non-planar space structure of the low expansion cavity 1 (the optical path in the low expansion cavity 1 is processed into the non-planar space structure, see the reference document: Dorschner TA. Nonplanr rings for laser gyros [ C ] Proc SPIE 487:192-202.), and provides frequency offset between the gyros I and II (the gyros I and II are a left-handed gyro and a right-handed gyro respectively) of the four-frequency differential laser gyro to avoid mode competition. 9 is a nonreciprocal offset frequency device, which generates nonreciprocal offset frequency between two modes with the same polarization of the four-frequency differential laser gyro to avoid locking. The four-frequency differential laser gyro operates in 4 modes in the cavity, wherein the modes 12 and 13 form a gyro I, and the modes 14 and 15 form a gyro II (see figure 2);
the device for measuring bandwidth and resolution according to the present invention is shown in fig. 3, and five parts of a light-combining prism 50, a photoelectric conversion and signal processing device 51, a computer 52, a current generating device 61 and a conductive coil 63 are added on the basis of fig. 1. The laser in the four-frequency differential laser gyro cavity partially penetrates out of the reflector 7, light is combined through the light combining prism 50, an optical signal is converted into an electric signal through the photoelectric detector, information such as difference frequency and light intensity is obtained after data processing is carried out through the photoelectric conversion and signal processing device 51 and then input into the computer 52, the difference frequency comprises sum frequency and difference frequency of frequency difference of the gyro I and the gyro II, and the difference frequency of the gyro is used as required difference frequency. The obtained difference frequency information is collected into the computer 52 for processing, and the pulses are subdivided by using a resolution enhancement technique [ see the reference: wang Fei, Husha people, FPGA-based four-frequency laser gyro high-resolution counting circuit [ J ]. laser journal, 2009,30(1):30-31 ]. The current generating device 61 and the conductive coil 62 together form a broadband magnetic field generating device for applying a magnetic field to the four-frequency differential laser gyro;
the current generating device 61 employs a function generator (e.g., Tek 3102F), a current power amplifier (e.g., NF4510), and an electrically conductive coil (e.g., helmholtz coil). When the Helmholtz coil is manufactured, the inductance is reduced as much as possible so as to ensure that the relative current output delay of the magnetic field generated by the broadband magnetic field generating device is less than 1 ms;
in order to reduce the influence of environmental vibration and temperature, the whole system is placed on a vibration isolation platform. The shock insulation platform is composed of a sandy soil foundation, a cement support and a marble platform, and the central axis direction of the four-frequency differential laser gyro is perpendicular to the ground. In order to reduce the influence of an environmental magnetic field, the four-frequency differential laser gyro is placed in a magnetic shielding box, and the shielding coefficient is superior to 10;
firstly, performing bandwidth test: recording the difference frequency pulse number sequence with the sampling time of 1ms, outputting a sinusoidal alternating current magnetic field with constant peak intensity and frequency of omega in the range of 0.1-1Hz by taking 0.1Hz as step length, and measuring the peak value N of the corresponding same-frequency difference frequency sequencepp(ii) a Respectively measuring the peak value of the difference frequency sequence at each frequency point by using the step length of 1Hz at 1Hz to 10Hz, the step length of 10Hz at 10Hz to 100Hz and the step length of 100Hz to 1000Hz, thereby obtaining Npp 
And (4) making a baud graph by using an omega data sequence, and solving the bandwidth of 3 dB. In fact, it is possible that the bandwidth of a four-frequency differential laser gyro is much greater than 1KHz, N in the frequency range of 0.1-1000HzppThe obvious reduction does not occur, and whether the shorter sampling time and the wider magnetic field frequency range are adopted can be determined according to actual needs;
then a resolution test at 1ms sampling is performed. The four-frequency differential laser gyro is preheated for half an hour to eliminate the influence of temperature transients. The output voltage of the function generator is 0, and the pulse number in 100s is recorded by 1s sampling time to obtain a pulse sequence N1s(n),n＝1,2,..100，N1sThe average value of (n), n is 1,2,. 100 is the measured zero-offset Ba0. The output voltage of the function generator is 1V, and then the zero offset B is measured by the same methoda1The absolute value of the difference is Delta B1＝|Ba1-Ba0|；
Recording pulse number in 1ms sampling time, firstly, the output voltage of function generator is 0, and recording 100 pulse sequences N1ms0(n), n ═ 1,2,. 100; then the output voltage of the function generator is 1V, and 100 pulse sequences N are recorded1ms1(n), n is 1,2,. 100. the average of these two sequences is determined
The absolute value of the difference between the two is
N1ms0(N), N ═ 1,2,. 100, and has a standard deviation Δ N1rms. The resolution is
Claims (5)
1. Four-frequency differential laser gyro bandwidth and angular resolution testing arrangement includes: the gyroscope comprises a constant temperature space, a magnetic shield, a vibration isolation device, a broadband adjustable magnetic field generating device and a gyroscope to be tested, wherein the broadband adjustable magnetic field generating device is adopted to apply a magnetic field on the gyroscope to be tested, output beat frequency information of the gyroscope to be tested is obtained through a photoelectric conversion and signal processing device, recording and data processing are carried out through a computer, and bandwidth and resolution ratio of the gyroscope to be tested are obtained after data processing is carried out through a generated magnetic field and a recorded corresponding pulse sequence; it is characterized in that the preparation method is characterized in that,
the adjustable magnetic field generating device in broadband is placed in the magnetic shield cover, includes: a conductive coil and a current generating device;
the gyroscope to be detected is arranged in a constant temperature space;
the broadband adjustable magnetic field generating device, the gyroscope to be tested and the constant temperature space are arranged in the magnetic shielding cover;
the magnetic shield is arranged on the vibration isolation device;
the broadband adjustable magnetic field generating device sends out a constant-strength sinusoidal magnetic field with frequency from direct current to high-frequency alternating current, records a magnetic beat frequency pulse sequence caused by the sinusoidal magnetic field corresponding to each frequency at set sampling time, calculates a data sequence of the variation of the magnetic beat frequency amplitude along with the frequency, and then calculates the bandwidth;
the broadband adjustable magnetic field generating device sends out at least 2 stable magnetic fields with different intensities, then corresponding magnetic zero offsets are recorded respectively, then beat frequency pulse sequences corresponding to different magnetic field intensities are recorded according to set sampling time, and the number of pulses distributed to the sampling time by the magnetic zero offsets is used as a scale so as to calculate the resolution.
2. The device for testing the bandwidth and the angular resolution of the four-frequency differential laser gyro of claim 1, wherein the current generation device adopts a function generator or a current power amplifier, and the conductive coil is a Helmholtz coil.
3. The device for testing the bandwidth and the angular resolution of the four-frequency differential laser gyro of claim 1, wherein the conductive coil is wound on a gain area of the gyro to be tested, or the gyro to be tested is placed inside the conductive coil.
4. The method for testing the bandwidth and the angular resolution of the four-frequency differential laser gyroscope of the device of claim 1, which comprises the following steps:
step 1, calibrating a magnetic difference frequency coefficient;
setting the magnetic field strength to H1Recording zero offset b (T) by using a test program of a four-frequency differential laser gyro, taking the acquisition time length as T, and calculating the average zero offset
Then the magnetic field strength is set to H2To find the corresponding average zero offset
The magnetic zero-bias coefficient is calculated as,
step 2, measuring resolution;
2.1, making the output magnetic field intensity of the broadband adjustable magnetic field generating device be 0, the corresponding current be 0, and recording the sampling time as TsWhen the gyroscope to be tested outputs a zero offset sequence b, recording M points to obtain a data sequence b (n), wherein n is 1,2, … and M;
2.2, following the step 2.1, continuously changing the output magnetic field intensity of the broadband adjustable magnetic field generating device into H1Corresponding current is I1Recording a sampling time of TsThen, the difference frequency output sequence of the gyroscope to be tested is recorded1Point, obtaining data sequence b1(n)，n＝1,2,…,M1The change of current from 0 to I is obtained according to the previously calibrated magnetic difference frequency coefficient K1The resulting magneto zero-bias change is Δ b1＝K×I1Halving to the sampling time TsHas a magnetic difference frequency of NH＝Δb1/Ts；
2.3, processing data: separately determining the data sequence b (n) and the data sequence b1(n) average value, and the absolute value of the difference is [ mu ]NStandard deviation of data sequence b (n)Is expressed as sigmaNThen the angular resolution is
Where S is the scale factor of the gyroscope and has the unit [ °/h]Per Hz;
step 3, bandwidth measurement;
the bandwidth measuring method uses a sine function magnetic field or a square wave magnetic field, taking the sine function magnetic field as an example: sending out a constant-strength sinusoidal magnetic field with frequency from direct current to high-frequency alternating current by a broadband adjustable magnetic field generating device, recording a magnetic difference frequency sequence caused by the sinusoidal magnetic field corresponding to each frequency at set sampling time, and calculating a change sequence of magnetic difference frequency amplitude along with the frequency of the alternating current magnetic field, namely calculating the bandwidth;
generation of H by using broadband adjustable magnetic field generator1sin (ω t) alternating magnetic field with amplitude H1The angular frequency is ω, which results in a difference frequency of B1sin (ω t), ω increasing from 0 up to ωcRecording the magnetic zero-offset amplitude corresponding to each angular frequency to obtain B1Omega curve, the curve is the amplitude-frequency response curve of the four-frequency differential laser gyro, 3dB bandwidth parameter is obtained by using signal processing technology, and because the amplitude-frequency response only needs the relative change of zero offset along with the frequency of the magnetic field, H does not need to be known1Specific values of (a).
5. The method of claim 4, wherein T is the bandwidth and angular resolution of the four-frequency differential laser gyrosAccording to the requirement, taking a gyro with an angle random walk smaller than 0.0005deg/sqrt (h) as an example, the data output time is set to be 1 ms.
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| CN105091844B (en) * | 2014-05-07 | 2017-10-31 | 中国航空工业第六一八研究所 | A kind of Dynamic High-accuracy angle-measuring equipment and method |
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| CN101008568A (en) * | 2006-01-27 | 2007-08-01 | 泰勒斯公司 | No-blind-area four-mode stable solid state laser gyroscope |
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| RU2794241C1 (en) * | 2022-07-26 | 2023-04-13 | Акционерное общество "ЛАЗЕКС" | Method for control of perimeter of cavity of four-frequency laser gyroscope |
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