Large laser gyroscope calibration method based on multi-wavelength measurement

Abstract

The invention discloses a large laser gyroscope calibration method based on multi-wavelength measurement, and relates to the technical field of laser gyroscopes. The large laser gyroscope based on multi-wavelength measurement comprises a laser light source, an annular resonant cavity, a beam combining interference device and a signal detection device, the laser light source is used for outputting laser of various wavelengths, and the laser of any wavelength is divided into two paths which are injected into the annular resonant cavity in the clockwise direction and the anticlockwise direction respectively. The annular resonant cavity is used for simultaneously resonating multiple pairs of clockwise and anticlockwise lasers with different wavelengths; the beam combining interference device combines the laser emitted from the output cavity mirror of the annular resonant cavity and separates the combined laser according to different wavelengths; and a plurality of signal photoelectric detectors of the signal detection device are used for detecting beat frequency signals of clockwise and anticlockwise lasers with corresponding wavelengths. By measuring Sagnac frequency output under different laser wavelength conditions, real-time and accurate calibration of the large laser gyroscope can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of laser gyroscopes, and in particular to a large laser gyroscope calibration method based on multi-wavelength measurement. Background Art

[0002] The laser gyroscope is an inertial device that uses laser technology to measure the angular velocity of an object. It has the characteristics of high resolution, good stability, and wide dynamic range. It has broad application prospects and important strategic significance in aerospace, navigation, national defense, industrial production lines, physical experiments, astronomical observations and other fields.

[0003] The scale factor of a laser gyroscope is the ratio of the Sagnac frequency to the angular velocity of the annular cavity, which reflects the sensitivity of the laser gyroscope to the input angular velocity. The stability and accuracy of the scale factor directly affect the measurement accuracy of the laser gyroscope. The scale factor is related to the area and circumference of the gyroscope annular cavity, the wavelength of the laser, and the angle between the gyroscope area normal vector and the rotation axis. Usually, small laser gyroscopes can be calibrated using a turntable due to their small size. The turntable is rotated at a known angular velocity or angle, and the data output by the laser gyroscope is collected. The output data is mathematically processed to calculate the scale factor. However, for large laser gyroscopes installed on the ground and used to accurately monitor the angular velocity of the earth's rotation, their area and circumference are defined by the propagation path of the laser, which are difficult to measure accurately, and the turntable calibration method is not applicable. Therefore, the accurate calibration of their scale factors has become a difficult problem that needs to be solved urgently. Summary of the invention

[0004] The invention provides a large laser gyroscope calibration method based on multi-wavelength measurement, aiming to achieve high-precision calibration of the large laser gyroscope.

[0005] The large-scale laser gyroscope based on multi-wavelength measurement provided by the present invention comprises a laser light source, a ring resonant cavity, a beam combining interference device and a signal detection device;

[0006] The laser light source is used to output lasers of multiple wavelengths, and the lasers of any wavelength are divided into two paths, which are injected into the ring resonant cavity in a clockwise direction and a counterclockwise direction respectively;

[0007] The ring resonant cavity comprises an input cavity mirror and an output cavity mirror; lasers of various wavelengths output by the laser light source are injected into the ring resonant cavity through the input cavity mirror, and are emitted from the output cavity mirror after the ring resonant cavity resonates;

[0008] The beam combining interference device combines the laser beams emitted from the output cavity mirror and separates the combined laser beams according to different wavelengths;

[0009] The signal detection device includes a plurality of signal photodetectors corresponding to the number of wavelengths emitted by the laser light source; each signal photodetector is used to receive the laser light processed by the beam combining interference device to detect the beat frequency signal of the laser light of the corresponding wavelength propagating in the clockwise and counterclockwise directions in the ring resonant cavity.

[0010] Optionally, the ring resonator is a square resonator consisting of three input mirrors and one output mirror; the input mirror and the output mirror are high-reflectivity mirrors, so that the laser injected from one of the input mirrors propagates clockwise in the ring resonator, and the laser injected from the other input mirror propagates counterclockwise in the ring resonator.

[0011] Optionally, the laser output by the laser light source is coupled to the resonance mode of the ring resonator through mode matching.

[0012] Optionally, a gain medium is provided in the ring resonator;

[0013] The gain medium is used to excite lasers of multiple wavelengths that propagate in the ring resonant cavity in clockwise and counterclockwise directions.

[0014] Optionally, the ring resonator is a square resonator consisting of three input mirrors and one output mirror; both the input mirror and the output mirror are high-reflectivity mirrors, so that the laser emitted by the gain medium propagates in the clockwise direction or counterclockwise direction in the ring resonator.

[0015] Optionally, the beam combining interference device includes a first reflector, a second reflector, a beam combiner and a grating;

[0016] The first reflector and the second reflector are used to reflect the laser emitted from the output cavity mirror to the beam combiner; after the laser emitted from the output cavity mirror is combined by the beam combiner, the combined laser is separated according to different wavelengths by a grating.

[0017] Optionally, the beam combining interference device is an integrated beam combining prism.

[0018] The present invention proposes a large laser gyroscope calibration method based on multi-wavelength measurement, which is used to calibrate the large laser gyroscope mentioned above. The method comprises the following steps:

[0019] S1, injecting at least two lasers with different wavelengths into the ring resonator; wherein the laser of any wavelength is divided into two paths, and injected into the ring resonator in a clockwise direction and a counterclockwise direction respectively;

[0020] S2, measuring the beat frequency signals of lasers with the same wavelength propagating in the ring resonator in clockwise and counterclockwise directions;

[0021] S3, according to the earth's rotation angular velocity and the beat frequency signal, solving the scaling factors corresponding to the lasers with different wavelengths through linear regression.

[0022] Optionally, in step S3, the scaling factor is solved according to the Sagnac formula:

[0023]

[0024] In the formula, is the Sagnac frequency; is the angular velocity of the ring cavity; A is the surrounding area vector of the ring resonator, is the wavelength of the laser, P is the circumference of the ring resonator, 4A / is the scale factor K of the large laser gyroscope s .

[0025] The present invention also provides a large laser gyroscope calibration tool, comprising a computer device and the large laser gyroscope described above;

[0026] The computer device includes a memory and a processor;

[0027] The memory stores a computer program; when the processor executes the computer program, the steps of the large laser gyroscope calibration method described above are implemented.

[0028] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0029] The present invention injects or excites laser signals of multiple wavelengths in a ring resonant cavity, so that a large laser gyroscope fixed on the surface of the earth can operate in multiple laser wavelength modes at the same time, thereby outputting multiple Sagnac frequencies, that is, obtaining beat frequency signals of clockwise and counterclockwise lasers of different wavelengths; through the difference in the output Sagnac frequencies under different wavelength conditions, the accurate value of its scale factor can be calculated through linear regression, thereby realizing real-time calibration of the large laser gyroscope and solving the difficult problem of accurate calibration of the large laser gyroscope. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 It is a structural schematic diagram of Embodiment 1 of a large laser gyroscope based on multi-wavelength measurement of the present invention;

[0032] Figure 2 It is a structural schematic diagram of Embodiment 2 of a large laser gyroscope based on multi-wavelength measurement of the present invention;

[0033] Figure 3 It is a structural schematic diagram of Embodiment 3 of a large laser gyroscope based on multi-wavelength measurement of the present invention;

[0034] Figure 4 It is a structural schematic diagram of Embodiment 4 of a large laser gyroscope based on multi-wavelength measurement of the present invention;

[0035] Figure 5 It is a structural schematic diagram of Embodiment 5 of a large laser gyroscope based on multi-wavelength measurement of the present invention;

[0036] Figure 6 The present invention is a flowchart of a large laser gyroscope calibration method based on multi-wavelength measurement.

[0037] Figure Number:

[0038] 100, ring resonator; 200, beam combining interferometer; 300, signal detection device; 101, first input cavity mirror; 102, second input cavity mirror; 103, third input cavity mirror; 104, output cavity mirror; 105, gain medium; 201, first reflector; 202, second reflector; 203, beam combiner; 204, grating; 301, first signal photodetector; 302, second signal photodetector; 303, third signal photodetector; 304, fourth signal photodetector;

[0039] 1001, first resonant laser; 1002, second resonant laser; 1003, third resonant laser; 1004, fourth resonant laser; 1005, fifth resonant laser; 1006, sixth resonant laser; 1007, seventh resonant laser; 1008, eighth resonant laser. DETAILED DESCRIPTION

[0040] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and drawings of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0042] The laser gyroscope measures the angular velocity of an object based on the Sagnac effect. The Sagnac effect was proposed by French scientist G. Sagnac in 1913. In a ring resonator, if the system rotates in the light propagation plane, the actual optical path of the light propagating in the clockwise direction is not equal to that of the light propagating in the counterclockwise direction. If two beams of light propagating in opposite directions in the cavity resonate with the same longitudinal mode resonance peak of the ring resonator at the same time, their resonance frequencies will have a difference due to the rotation. This phenomenon satisfies the Sagnac formula:

[0043]

[0044] in, It is called Sagnac frequency, which is the frequency difference between the resonant laser in the clockwise and counterclockwise directions. This frequency difference phenomenon is also called beat frequency. A is the surrounding area of ​​the ring cavity. is the wavelength of the laser, P is the circumference of the ring cavity, is the angular velocity of the ring cavity; in the laser gyroscope, the output Sagnac frequency is proportional to the rotation felt by the ring cavity, 4A / It is called the scale factor K of the laser gyro S .

[0045] Laser gyroscopes include small laser gyroscopes and large laser gyroscopes. Small laser gyroscopes are smaller in size, usually in the order of a few centimeters to more than ten centimeters, and are suitable for navigation and attitude control in aerospace, ships, vehicles, missiles, etc. Large laser gyroscopes are larger than meters in size and are usually installed on the ground. The gyroscope ring cavity must be strapped to the earth, and are used in large scientific research facilities, geodetic surveying, and professional fields with extremely high precision requirements, such as large observatories and geophysical research institutions.

[0046] Among them, the small laser gyroscope is small in size and can be calibrated using a turntable. The process of experimentally calibrating the scale factor of a small laser gyroscope is a precise and complex task, which aims to ensure the accurate correspondence between the data output by the laser gyroscope and the actual rotation speed or angle. First, preparatory work is carried out, including environmental stabilization and equipment status inspection. Then, the parameters of the laser gyroscope and turntable are set to ensure that they meet the experimental requirements. After the equipment is installed, the laser gyroscope is calibrated for zero bias and sensitivity to ensure data accuracy. Then, the experiment is started, and the laser gyroscope is rotated at a known angular velocity or angle through the turntable, while collecting The collected data is processed, including denoising, filtering and correction, to ensure its accuracy and reliability. Then, a mathematical model or fitting algorithm is used to calculate the scale factor, which reflects the proportional relationship between the output data of the laser gyroscope and the actual rotation speed or angle. After the scale factor is calculated, it is verified and adjusted, usually by comparing it with other measuring equipment of known accuracy or performing multiple calibration experiments to verify its accuracy, and necessary adjustments are made to improve the calibration accuracy. Finally, the determined scale factor and detailed information of the experimental process are recorded and saved as a reference value for future measurements using the laser gyroscope.

[0047] The entire calibration process of a small laser gyroscope requires strict operating procedures and precise data processing to ensure the reliability and accuracy of the laser gyroscope in high-precision applications.

[0048] However, the area and circumference of a large laser gyroscope installed on the ground are defined by the propagation path of the laser, which is difficult to measure accurately, and the turntable calibration method is not applicable. The high-precision calibration of large laser gyroscopes is still a problem that needs to be solved urgently.

[0049] The present invention proposes a large laser gyroscope based on multi-wavelength measurement and a calibration method thereof, aiming to solve the above problems.

[0050] See also Figures 1 to 5 In one embodiment, a large laser gyroscope based on multi-wavelength measurement includes a laser light source, a ring resonator 100 , a beam combining interferometer 200 and a signal detection device 300 .

[0051] The laser light source is used to output lasers of various wavelengths. Lasers of any wavelength are divided into two paths and injected into the ring resonator 100 in a clockwise direction and a counterclockwise direction respectively.

[0052] The ring resonator 100 includes an input cavity mirror and an output cavity mirror; lasers of various wavelengths output by the laser light source are injected into the ring resonator 100 through the input cavity mirror, and are emitted from the output cavity mirror after resonating in the ring resonator 100.

[0053] The beam combining interference device 200 combines the laser beams emitted from the output cavity mirrors and separates the combined laser beams according to different wavelengths.

[0054] The signal detection device 300 includes a plurality of signal photodetectors corresponding to the number of wavelengths emitted by the laser light source; each signal photodetector is used to receive the laser processed by the beam combining interference device 200 to detect the beat frequency signal of the laser of the corresponding wavelength propagating in the clockwise and counterclockwise directions in the ring resonator 100.

[0055] In this embodiment, the lasers of multiple wavelengths refer to lasers of at least two different wavelengths. The lasers of the same wavelength propagating in the clockwise direction and the counterclockwise direction in the ring resonator respectively constitute a pair of clockwise and counterclockwise lasers. The lasers injected into the ring resonator 100 for resonance at the same time include at least four laser beams. In the following description, the lasers injected into the ring resonator 100 for resonance are collectively referred to as resonant lasers.

[0056] In one feasible implementation, the laser light source uses a supercontinuum light source to generate laser light covering a wider wavelength range, and is combined with a wavelength selection device such as a grating, a filter or a tunable filter to select a specific wavelength range or a single wavelength.

[0057] In another feasible implementation, the laser light source uses multiple independent lasers to generate lasers of different wavelengths, and then combines the multiple laser beams of different wavelengths through a beam combining device and injects them into the ring resonator.

[0058] In another feasible implementation, the laser light source uses a tunable laser to continuously or discretely adjust the output wavelength within a certain wavelength range, and cooperates with control technology to achieve switching or simultaneous output of multiple wavelengths.

[0059] In another feasible implementation, the laser light source can also generate new wavelengths by injecting one or more fundamental frequency lasers into a nonlinear crystal; and the generation and injection of multiple wavelengths can be achieved by combining different fundamental frequency lasers and nonlinear crystals.

[0060] In this embodiment, the resonant laser is coupled to the resonant mode of the ring resonator 100 through mode matching; the coupling adopts conventional optical elements, such as a reflector, a beam splitter, a convex lens, a concave lens, etc.

[0061] In this embodiment, the ring resonator 100 generally includes a multi-faceted input cavity mirror and an output cavity mirror; by injecting the resonant laser from different input cavity mirrors, that is, injecting the resonant laser into the ring resonator 100 from different rotation directions, the clockwise laser or counterclockwise laser mentioned above is obtained, and the resonated laser is emitted through the output cavity mirror.

[0062] In this embodiment, the beam combining interference device 200 generally includes at least a beam combiner and a grating. The beam combiner first completes the beam combining of the outgoing lasers, and the clockwise laser and the counterclockwise laser of the same wavelength are accurately superimposed to produce an interference effect. The grating is then used to separate the laser beams with different wavelength components. The separated laser beams are received by the corresponding signal photodetectors to analyze the beat frequency signals of the clockwise and counterclockwise lasers of different wavelengths, that is, to obtain the Sagnac frequency outputs of the clockwise and counterclockwise lasers of different wavelengths.

[0063] In this embodiment, when the large laser gyroscope rotates with the earth, due to the Sagnac effect, the optical path lengths of the clockwise laser and the counterclockwise laser through the circular optical path in the ring resonator will be different, resulting in different phases when they are superimposed at the beam combining interference device, resulting in a frequency difference, that is, generating beat frequency signals of the clockwise and counterclockwise lasers of corresponding wavelengths.

[0064] Furthermore, in this embodiment, the scale factors corresponding to different wavelengths may be calculated according to the Sagnac formula.

[0065] Furthermore, this embodiment can reduce the calculation error of the scale factor by using a linear regression mathematical method based on the Sagnac formula by measuring different simultaneous equations of Sagnac frequencies and wavelengths.

[0066] Therefore, the embodiment of the present invention measures the Sagnac frequency output under different laser wavelength conditions, thereby solving the scale factor of the large laser gyroscope and completing the calibration of the instrument; the embodiment of the present invention converts the measurement of area and circumference into the measurement of frequency, which can overcome the difficulty of high-precision determination of the photon path, and realizes real-time and accurate calibration of the large laser gyroscope.

[0067] Based on the above embodiments, refer to Figure 1 and Figure 2 In a specific embodiment, the ring resonator 100 is a square resonator consisting of three input mirrors and one output mirror; the input mirror and the output mirror are high-reflectivity mirrors, so that the resonant laser beam injected from one of the input mirrors propagates clockwise in the ring resonator 100, and the resonant laser beam injected from the other input mirror propagates counterclockwise in the ring resonator 100.

[0068] In this embodiment, the ring resonator is a passive resonator, and an external laser beam is injected into the ring resonator to excite oscillation. The frequency of the resonant laser beam is locked with the resonant frequency of the ring resonator, and the difference between the two is equal to the Sagnac frequency. The resonant laser beam is emitted from the output cavity mirror after being enhanced by the resonance of the ring resonator. The passive laser gyroscope using a passive resonator can reduce the shot noise limit of the system by increasing the injected laser power, and has a better potential limit level.

[0069] In another specific embodiment, see Figure 3 , a gain medium is provided in the ring resonator.

[0070] In this embodiment, the ring resonator is an active resonator, and the gain medium is used to excite monochromatic laser beams that propagate clockwise and counterclockwise in the ring resonator, respectively, and emit from the output cavity mirror after resonance of the ring resonator. The difference between the two frequencies is also equal to the Sagnac frequency. The active laser gyroscope using the active resonator has a relatively simple structure, and complex problems such as high-precision optical cavity mode and laser feedback locking can be avoided in the design.

[0071] Furthermore, in a specific embodiment, in order to facilitate adjustment and optimization of the device to adapt to different experimental environments and conditions, the beam combining interference device can be constructed using split optical elements.

[0072] Specifically, see Figure 1 The beam combining interference device 200 includes a first reflecting mirror 201, a second reflecting mirror 202, a beam combiner 203 and a grating 204.

[0073] The first reflector 201 and the second reflector 202 are used to reflect the outgoing laser of the ring resonator 100 to the beam combiner 203; the beam combiner 203 combines the outgoing laser of the ring resonator 100; and the grating separates the combined lasers of different wavelengths.

[0074] In another specific embodiment, in order to improve the accuracy, stability and compactness of the device, the beam combining interference device may also use an integrated beam combining prism.

[0075] Based on the large laser gyroscope based on multi-wavelength measurement described above, see Figure 6 In one embodiment, the large laser gyroscope calibration method based on multi-wavelength measurement proposed by the present invention comprises the steps of:

[0076] S1, injecting at least two lasers with different wavelengths into the ring resonator; wherein the laser of any wavelength is divided into two paths, and injected into the ring resonator in a clockwise direction and a counterclockwise direction respectively.

[0077] S2, measure the beat frequency signal of each pair of clockwise and counterclockwise lasers.

[0078] S3, according to the angular velocity of the earth's rotation and the beat frequency signals of clockwise and counterclockwise lasers with different wavelengths, the scaling factors corresponding to the lasers with different wavelengths are solved by linear regression.

[0079] In step S3, the scaling factor is solved according to the Sagnac formula:

[0080]

[0081] In the formula, is the Sagnac frequency, i.e., the beat frequency of the resonant laser in both clockwise and counterclockwise directions; is the angular velocity of the annular cavity, that is, the angular velocity of the earth's rotation; A is the surrounding area vector of the annular resonator, is the wavelength of the laser, P is the circumference of the ring resonator, 4A / is the scale factor K of the large laser gyroscope s .

[0082] By determining the difference in Sagnac frequency output under different wavelength conditions, the angular velocity of the earth's rotation can be determined. The accurate value of its scale factor can be calculated by combining the Sagnac formulas corresponding to different wavelengths, thereby realizing real-time calibration of large laser gyroscopes.

[0083] Based on the aforementioned embodiment of a large laser gyroscope based on multi-wavelength measurement and a calibration method thereof, the present invention proposes the following specific embodiments:

[0084] Example 1

[0085] See also Figure 1 The large laser gyroscope based on multi-wavelength measurement includes a ring resonator 100, a beam combining interferometer 200 and a signal detection device 300.

[0086] Among them, the ring resonator 100 includes a first input cavity mirror 101, a second input cavity mirror 102, a third input cavity mirror 103 and an output cavity mirror 104 arranged in a square; the beam combining interference device 200 includes a first reflector 201, a second reflector 202, a combiner 203 and a grating 204; the signal detection device 300 includes a first signal photodetector 301 and a second signal photodetector 302.

[0087] Four resonant laser beams (1001, 1002, 1003, 1004) are injected into the ring resonant cavity, where the wavelengths of the first resonant laser 1001 and the second resonant laser 1002 are 1. The wavelengths of the third resonance laser 1003 and the fourth resonance laser 1004 are 2; wherein the first resonant laser 1001 and the third resonant laser 1003 are injected into the ring resonant cavity 100 from the first input cavity mirror 101 in a clockwise direction, and the second resonant laser 1002 and the fourth resonant laser 1004 are injected into the ring resonant cavity 100 from the second input cavity mirror 102 in a counterclockwise direction.

[0088] The first resonant laser 1001 and the second resonant laser 1002 constitute a first group of clockwise and counterclockwise lasers for measuring Sagnac frequency, and the third resonant laser 1003 and the fourth resonant laser 1004 constitute a second group of clockwise and counterclockwise lasers for measuring Sagnac frequency.

[0089] After the four resonant laser beams are resonated by the ring resonator 100, the laser beams with the same wavelength are combined by the beam combiner 203 to interfere with each other, and then the laser beams with different wavelengths are separated by the grating 204; then the beat signal of the first resonant laser beam 1001 and the second resonant laser beam 1002 is detected by the first signal photoelectric detector 301 The beat frequency signal of the third resonant laser 1003 and the fourth resonant laser 1004 is detected by the second signal photodetector 302 .

[0090] Based on the obtained beat frequency signal and the angular velocity of the earth's rotation, the simultaneous equations are obtained through the Sagnac formula:

[0091]

[0092] Individual measurements to determine different wavelengths 1. 2, different wavelengths can be calculated 1. 2 The scale factor K of the large laser gyroscope is S1 , K S2 .

[0093] Example 2

[0094] See also Figure 2 The implementation process of this embodiment refers to that of Embodiment 1, and the difference from Embodiment 1 is that the first resonant laser 1001 and the third resonant laser 1003 of this embodiment are injected into the ring resonant cavity 100 from the third input cavity mirror 103 in a clockwise direction.

[0095] Example 3

[0096] See also Figure 3 The implementation process of this embodiment refers to that of Embodiment 1, and the difference from Embodiment 1 is that the ring resonator 100 of this embodiment is an active resonator, and a gain medium 105 is provided in the ring resonator 100. The gain medium 105 generates gain through electrical excitation to make the ring resonator 100 a ring helium-neon laser, and emits a first resonant laser 1001 and a third resonant laser 1003 in a clockwise direction, and emits a second resonant laser 1002 and a fourth resonant laser 1004 in a counterclockwise direction.

[0097] Example 4

[0098] See also Figure 4The implementation process of this embodiment refers to that of Embodiment 1. The difference from Embodiment 1 is that in this embodiment, six resonant laser beams (1001, 1002, 1003, 1004, 1005, 1006) are injected into the ring resonant cavity 100, wherein the wavelengths of the first resonant laser beam 1001 and the second resonant laser beam 1002 are 1. The wavelengths of the third resonance laser 1003 and the fourth resonance laser 1004 are 2. The wavelengths of the fifth resonant laser 1005 and the sixth resonant laser 1006 are 3.

[0099] Among them, the first resonant laser 1001, the third resonant laser 1003 and the fifth resonant laser 1005 are injected into the ring resonator 100 from the first input cavity mirror 101 along the clockwise direction, and the second resonant laser 1002, the fourth resonant laser 1004 and the sixth resonant laser 1006 are injected into the ring resonator 100 from the second input cavity mirror 102 along the counterclockwise direction.

[0100] The first resonant laser 1001 and the second resonant laser 1002 constitute a first group of clockwise and counterclockwise lasers for measuring Sagnac frequency, the third resonant laser 1003 and the fourth resonant laser 1004 constitute a second group of clockwise and counterclockwise lasers for measuring Sagnac frequency, and the fifth resonant laser 1005 and the sixth resonant laser 1006 constitute a third group of clockwise and counterclockwise lasers for measuring Sagnac frequency.

[0101] Accordingly, the signal detection device 300 includes a first signal photodetector 301, a second signal photodetector 302 and a third signal photodetector 303, which respectively detect 1. 2. 3 The Sagnac frequencies corresponding to the three pairs of clockwise and counterclockwise lasers with different wavelengths can be calculated based on the simultaneous equations of the Sagnac formula to obtain the frequencies of the three pairs of clockwise and counterclockwise lasers with different wavelengths. 1. 2. 3 The scale factor K of the large laser gyroscope S1 , K S2 , K S3 .

[0102] Furthermore, the calculation error can be reduced by using a linear regression method to obtain a more accurate value of the scale factor.

[0103] Example 5

[0104] See also Figure 5The implementation process of this embodiment refers to that of Embodiment 1. The difference from Embodiment 1 is that in this embodiment, eight resonant laser beams (1001, 1002, 1003, 1004, 1005, 1006, 1007, 1008) are injected into the ring resonant cavity 100, wherein the wavelengths of the first resonant laser beam 1001 and the second resonant laser beam 1002 are 1. The wavelengths of the third resonance laser 1003 and the fourth resonance laser 1004 are 2. The wavelengths of the fifth resonant laser 1005 and the sixth resonant laser 1006 are 3. The wavelengths of the seventh resonance laser 1007 and the eighth resonance laser 1008 are 4.

[0105] Among them, the first resonant laser 1001, the third resonant laser 1003, the fifth resonant laser 1005 and the seventh resonant laser 1007 are injected into the ring resonator 100 from the first input cavity mirror 101 along the clockwise direction, and the second resonant laser 1002, the fourth resonant laser 1004, the sixth resonant laser 1006 and the eighth resonant laser 1008 are injected into the ring resonator 100 from the second input cavity mirror 102 along the counterclockwise direction.

[0106] The first resonant laser 1001 and the second resonant laser 1002 constitute a first group of clockwise and counterclockwise lasers for measuring Sagnac frequency, the third resonant laser 1003 and the fourth resonant laser 1004 constitute a second group of clockwise and counterclockwise lasers for measuring Sagnac frequency, the fifth resonant laser 1005 and the sixth resonant laser 1006 constitute a third group of clockwise and counterclockwise lasers for measuring Sagnac frequency, and the seventh resonant laser 1007 and the eighth resonant laser 1008 constitute a fourth group of clockwise and counterclockwise lasers for measuring Sagnac frequency.

[0107] Accordingly, the signal detection device 300 includes a first signal photodetector 301, a second signal photodetector 302, a third signal photodetector 303 and a fourth signal photodetector 304, which respectively detect 1. 2. 3. 4 The Sagnac frequencies corresponding to the four pairs of clockwise and counterclockwise lasers with different wavelengths can be calculated based on the simultaneous equations of the Sagnac formula to obtain the frequencies of the four pairs of clockwise and counterclockwise lasers with different wavelengths. 1. 2. 3. 4 The scale factor K of the large laser gyroscope S1 , K S2 , K S3 , K S4 .

[0108] Furthermore, the calculation error can be reduced by using a linear regression method to obtain a more accurate value of the scale factor.

[0109] As can be seen from the above, the embodiment of the large-scale laser gyroscope and its calibration method based on multi-wavelength measurement of the present invention aims at the calibration difficulty of the large-scale laser gyroscope due to the difficulty in accurately measuring the area and circumference. A scheme using wavelength modulation is proposed to measure the Sagnac frequency output under different laser wavelength conditions, thereby obtaining the scale factor value of the large-scale laser gyroscope in real time, and completing the high-precision calibration of the instrument; this scheme converts the measurement of area and circumference into the measurement of frequency, which can overcome the problem that the photon path is difficult to determine with high precision, and is helpful to use a large-scale laser gyroscope to complete the high-precision measurement of the earth's rotation, and provides certain theoretical and experimental guidance for the high-precision calibration of large-scale laser gyroscopes in the future.

[0110] The present invention further proposes a large laser gyroscope calibration tool. In one embodiment, the calibration tool includes a computer device and the large laser gyroscope based on multi-wavelength measurement provided by the above embodiment.

[0111] In this embodiment, the computer device includes a memory and a processor; the memory stores a computer program; when the processor executes the computer program, the steps of the embodiment of the aforementioned large laser gyroscope calibration method are implemented. Therefore, the computer device can achieve the technical effects that can be achieved by the method provided in the aforementioned embodiment, which will not be repeated here.

[0112] In this embodiment, when the processor executes the computer program, it communicates and controls other instruments and equipment of the calibration tooling, such as lasers, signal detection devices, etc., through various interfaces to realize an automated testing process; in addition, the computer equipment also includes modules such as data storage and management, and data visualization, which are convenient for operators to query and analyze.

[0113] Those skilled in the art will appreciate that the computer program may be stored in a readable storage medium, and any reference to memory, storage, database, or other storage medium used in this embodiment may include at least one of non-volatile and volatile memory.

[0114] It can be understood that the large-scale laser gyroscope calibration tool proposed in the present invention can be used as a large-scale laser gyroscope measurement system to perform real-time measurement of the earth's rotation angular velocity after completing the calibration of the scale factor; in this case, the computer equipment is also used to calculate the earth's rotation angular velocity through the Sagnac formula based on the beat frequency signal and the scale factor calibrated by the above method.

[0115] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A large laser gyroscope based on multi-wavelength measurement, characterized in that: It includes a laser light source, a ring resonator, a beam combining interference device and a signal detection device; The laser light source is used to output lasers of multiple wavelengths; the laser of any wavelength is divided into two paths, and injected into the ring resonant cavity in a clockwise direction and a counterclockwise direction respectively; The ring resonant cavity comprises an input cavity mirror and an output cavity mirror; lasers of various wavelengths output by the laser light source are injected into the ring resonant cavity through the input cavity mirror, and are emitted from the output cavity mirror after the ring resonant cavity resonates; The beam combining interference device combines the laser beams emitted from the output cavity mirror and separates the combined laser beams according to different wavelengths; The signal detection device includes a plurality of signal photoelectric detectors corresponding to the number of wavelengths emitted by the laser light source; Each signal photoelectric detector is used to receive the laser light processed by the beam combining interference device to detect the beat frequency signal of the laser light of corresponding wavelength propagating in the clockwise direction and the counterclockwise direction in the ring resonant cavity.

2. The large laser gyroscope based on multi-wavelength measurement as claimed in claim 1, characterized in that: The ring resonator is a square resonator consisting of three input mirrors and one output mirror; both the input mirror and the output mirror are high-reflectivity mirrors, so that the laser injected from one of the input mirrors propagates clockwise in the ring resonator, and the laser injected from the other input mirror propagates counterclockwise in the ring resonator.

3. The large laser gyroscope based on multi-wavelength measurement as claimed in claim 2, characterized in that: The laser light outputted by the laser light source is coupled to the resonance mode of the ring resonator through mode matching.

4. The large laser gyroscope based on multi-wavelength measurement as claimed in claim 1, characterized in that: A gain medium is provided in the ring resonant cavity; The gain medium is used to excite lasers of multiple wavelengths that propagate in the ring resonant cavity in clockwise and counterclockwise directions.

5. The large laser gyroscope based on multi-wavelength measurement as claimed in claim 4, characterized in that: The ring resonator is a square resonator consisting of three input mirrors and one output mirror; both the input mirror and the output mirror are high-reflectivity mirrors, so that the laser emitted by the gain medium propagates in the clockwise direction or counterclockwise direction in the ring resonator.

6. The large laser gyroscope based on multi-wavelength measurement as claimed in claim 1, characterized in that: The beam combining interference device comprises a first reflector, a second reflector, a beam combiner and a grating; The first reflector and the second reflector are used to reflect the laser emitted from the output cavity mirror to the beam combiner; after the laser emitted from the output cavity mirror is combined by the beam combiner, the combined laser is separated according to different wavelengths by a grating.

7. The large laser gyroscope based on multi-wavelength measurement as claimed in claim 1, characterized in that: The beam combining interference device is an integrated beam combining prism.

8. A large laser gyroscope calibration method based on multi-wavelength measurement, characterized in that: Used to calibrate a large laser gyroscope according to any one of claims 1 to 7, the method comprising the steps of: S1, injecting at least two lasers with different wavelengths into the ring resonator; wherein the laser of any wavelength is divided into two paths, and injected into the ring resonator in a clockwise direction and a counterclockwise direction respectively; S2, measuring the beat frequency signals of lasers with the same wavelength propagating in the ring resonator in clockwise and counterclockwise directions; S3, according to the earth's rotation angular velocity and the beat frequency signal, solving the scaling factors corresponding to the lasers with different wavelengths through linear regression.

9. The large laser gyroscope calibration method based on multi-wavelength measurement as claimed in claim 8, characterized in that: In step S3, the scaling factor is solved according to the Sagnac formula: In the formula, is the Sagnac frequency; is the angular velocity of the ring cavity; A is the surrounding area vector of the ring resonator, is the wavelength of the laser, P is the circumference of the ring resonator, 4A / is the scale factor K of the large laser gyroscope s .

10. A large laser gyroscope calibration tool, characterized in that: A computer device and a large laser gyroscope based on multi-wavelength measurement according to any one of claims 1 to 7; The computer device includes a memory and a processor; The memory stores a computer program; when the processor executes the computer program, the steps of the large laser gyroscope calibration method based on multi-wavelength measurement described in claim 8 or 9 are implemented.

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