A method and system for measuring an optical accelerometer

Abstract

The application discloses a kind of measurement method and system of optical accelerometer, it is related to acceleration measurement technical field, the method includes: based on optical accelerometer, the first reflection spectrum of phase shift Bragg grating of measured object under no vibration condition is acquired to determine first phase shift peak wavelength position;Second reflection spectrum is acquired under the condition of being subjected to external vibration to determine second phase shift peak wavelength position, determine phase change information;Based on first phase shift peak wavelength position, second phase shift peak wavelength position and phase change information, the initial acceleration of measured object is determined;Based on optical accelerometer, the wavelength position of Bragg grating resonance peak sideband is acquired to carry out ambient temperature analysis;Based on target ambient temperature, temperature drift compensation model is used for correction coefficient analysis to calibrate initial acceleration, obtain target acceleration.The application effectively improves the measurement precision of optical accelerometer, and constructs complete closed loop from temperature measurement to acceleration correction.

Description

Technical Field

[0001] This invention relates to the field of acceleration measurement technology, and in particular to a measurement method and system for an optical accelerometer. Background Technology

[0002] Optical accelerometers, due to their advantages such as resistance to electromagnetic interference, small size, and long-distance transmission capability, have shown broad application prospects in fields such as strong electromagnetic environments, large-scale structural health monitoring, and high-precision inertial navigation. However, the optical sensing materials of optical accelerometers are highly sensitive to temperature. Changes in ambient temperature directly cause characteristic peak wavelength shifts. This thermally induced drift and acceleration-induced drift are difficult to distinguish spectrally, leading to severe temperature cross-sensitivity errors and hindering the improvement of measurement accuracy. To address the temperature interference problem, current methods typically involve adding an optical reference unit near the sensing structure, unaffected by inertial forces and sensing only ambient temperature. Differential measurements are used to eliminate temperature influences. However, when the temperature field distribution is uneven, spatial differences exist between the reference unit and the sensing unit, meaning the sensed temperature does not equal the true temperature of the sensing unit, resulting in residual errors in compensation. Furthermore, this method fails to extract temperature-indicating information from the spectral response of the optical sensing structure itself, preventing the sensor from achieving self-sensing of temperature and thus hindering the construction of a complete closed loop from temperature measurement to acceleration correction. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a measurement method and system for an optical accelerometer, which effectively improves the measurement accuracy of the optical accelerometer and constructs a complete closed loop from temperature measurement to acceleration correction.

[0004] To address the aforementioned technical problems, the present invention provides a measurement method for an optical accelerometer, the method comprising: The first reflection spectrum of the phase-shifted Bragg grating of the object under test is obtained by an optical accelerometer under vibration-free conditions, and the wavelength position of the first phase-shifted peak is determined based on the first reflection spectrum. The second reflection spectrum of the phase-shifted Bragg grating of the measured object under external vibration is obtained by an optical accelerometer, and the wavelength position of the second phase-shifted peak is determined based on the second reflection spectrum, and the phase change information is determined based on the second reflection spectrum. Acceleration analysis is performed based on the wavelength positions of the first and second phase shift peaks and phase change information to obtain the initial acceleration of the object under test. The wavelength position of the Bragg grating resonance peak sideband is obtained by using an optical accelerometer, and the ambient temperature is analyzed using the temperature sideband drift function based on the wavelength position to obtain the target ambient temperature. A temperature drift compensation model is constructed. Based on the target ambient temperature, the temperature drift compensation model is used to perform correction coefficient analysis to obtain the target correction coefficient. Based on the target correction coefficient, the initial acceleration is calibrated to obtain the target acceleration of the measured object.

[0005] Optionally, determining the wavelength position of the first phase shift peak based on the first reflection spectrum includes: Perform a Fourier transform on the first reflection spectrum to obtain spatial frequency domain information, and determine the characteristic frequency components based on the spatial frequency domain information; Inverse Fourier transform is performed based on the characteristic frequency components to obtain spectral profile information, and the center wavelength of the phase shift peak energy distribution is analyzed based on the spectral profile information. The wavelength position of the first phase shift peak is determined based on the center wavelength.

[0006] Optionally, determining the phase change information based on the second reflectance spectrum includes: The first interference sideband region is analyzed based on the first reflection spectrum, and the spectral abscissa is mapped based on the first interference sideband region to obtain the first interferogram; The second interference sideband region is analyzed based on the second reflection spectrum, and the spectral abscissa is mapped based on the second interference sideband region to obtain the second interferogram; The static reference phase is determined based on the first interferogram, the instantaneous phase is determined based on the second interferogram, and a differential operation is performed based on the static reference phase and the instantaneous phase to obtain phase change information.

[0007] Optionally, the step of performing acceleration analysis based on the wavelength positions of the first and second phase shift peaks and phase change information to obtain the initial acceleration of the object under test includes: The wavelength shift is determined based on the wavelength positions of the first and second phase shift peaks, and the wavelength shift is then converted using a preset strain-wavelength conversion coefficient to obtain the average axial strain change of the optical fiber. The coarse acceleration value is determined based on the average axial strain change of the optical fiber. Phase unwrapping is performed on the phase change information to obtain the phase time history, and the cavity length displacement is determined based on the phase time history. Second-order numerical differentiation is performed based on the cavity length displacement to obtain the fine acceleration components. Acceleration analysis is performed based on the coarse acceleration measurement and the fine acceleration components to obtain the initial acceleration of the object being measured.

[0008] Optionally, the step of performing environmental temperature analysis based on the wavelength position using a temperature sideband drift function to obtain the target environmental temperature includes: Construct the temperature sideband drift function; The target reflected light power at the wavelength position is determined, and the target reflected light power is filtered to obtain the filtered target reflected light power. The target ambient temperature is obtained by analyzing the optical power ratio based on the filtered target reflected light power and using the temperature sideband drift function based on the optical power ratio.

[0009] Optionally, the construction of the temperature sideband drift function includes: The first reflected light power corresponding to the upper reference wavelength position and the second reflected light power corresponding to the lower reference wavelength position were obtained during the experiment of the optical accelerometer at each temperature step. Calculate the target ratio of the first reflected light power and the second reflected light power; Based on the target ratio and temperature step, a temperature-optical power ratio data point sequence is generated, and curve fitting is performed on the temperature-optical power ratio data point sequence to obtain a continuous mapping curve; The temperature sideband drift function is determined based on the continuous mapping curve.

[0010] Optionally, the construction of the temperature drift compensation model includes: Construct a grating parameter thermochromic layer; The energy storage modulus and loss factor of the material sample of the optical accelerometer are obtained within the operating temperature range, and the stiffness reduction factor at each temperature point is analyzed based on the energy storage modulus. The temperature variation relationship of the structural damping factor is determined based on the loss factor, and a phase shift correction library is constructed based on the temperature variation relationship. A mechanical parameter temperature variation layer is constructed based on the phase shift correction library and the stiffness reduction coefficient at each temperature point. The wavelength splitting amount of the phase shift peak corresponding to the orthogonal polarization intrinsic mode in the reflection spectrum of the phase-shifted Bragg grating at different temperatures is obtained, and a relationship curve is constructed based on the wavelength splitting amount and the corresponding temperature point; A cross-sensitive decoupling layer is constructed based on the relationship curve, and a temperature drift compensation model is constructed based on the grating parameter temperature-varying layer, the mechanical parameter temperature-varying layer, and the cross-sensitive decoupling layer.

[0011] Optionally, the construction of the grating parameter temperature-varying layer includes: The thermo-optic coefficient and thermal expansion coefficient of the material sample of the optical accelerometer are obtained in the measurement temperature range, and a sensitivity temperature scaling factor table is constructed based on the thermo-optic coefficient and thermal expansion coefficient. The phase temperature change information of the reference optical fiber in the measurement temperature range is obtained, and the phase strain compensation factor change curve is determined based on the phase temperature change information. A temperature-varying grating parameter layer is constructed based on the sensitivity temperature scaling factor table and the phase strain compensation factor variation curve.

[0012] Optionally, the step of performing correction coefficient analysis based on the target ambient temperature using the temperature drift compensation model to obtain the target correction coefficient includes: The target ambient temperature is input into the temperature drift compensation model, and the output includes the sensitivity temperature scaling factor, phase strain compensation factor, stiffness reduction factor, dynamic response correction function, and polarization coupling perturbation correction factor. The target correction coefficient is obtained by weighted fusion of the sensitivity temperature scaling factor, phase strain compensation factor, stiffness reduction factor, dynamic response correction function and polarization coupling perturbation correction coefficient.

[0013] In addition, the present invention also provides a measurement system for an optical accelerometer, the system comprising: First information analysis module: used to acquire the first reflection spectrum of the phase-shifted Bragg grating of the object under test in the absence of vibration based on the optical accelerometer, and to determine the wavelength position of the first phase-shifted peak based on the first reflection spectrum; The second information analysis module is used to acquire the second reflection spectrum of the phase-shifted Bragg grating of the measured object under external vibration based on the optical accelerometer, determine the wavelength position of the second phase-shift peak based on the second reflection spectrum, and determine the phase change information based on the second reflection spectrum. Initial acceleration module: used to perform acceleration analysis based on the wavelength positions of the first phase shift peak and the second phase shift peak and phase change information to obtain the initial acceleration of the object under test; Ambient temperature analysis module: used to obtain the wavelength position of the Bragg grating resonance peak sideband based on the optical accelerometer, and to perform ambient temperature analysis based on the wavelength position using the temperature sideband drift function to obtain the target ambient temperature; Correction module: Used to construct a temperature drift compensation model, perform correction coefficient analysis based on the target ambient temperature using the temperature drift compensation model to obtain the target correction coefficient, and calibrate the initial acceleration based on the target correction coefficient to obtain the target acceleration of the measured object.

[0014] In this embodiment of the invention, the first reflection spectrum of the phase-shifted Bragg grating of the object under vibration-free conditions is obtained using an optical accelerometer to determine the wavelength position of the first phase-shift peak; the second reflection spectrum of the phase-shifted Bragg grating of the object under external vibration conditions is obtained using an optical accelerometer to determine the wavelength position of the second phase-shift peak, and the phase change information is determined based on the second reflection spectrum; acceleration analysis is performed based on the wavelength positions of the first and second phase-shift peaks and the phase change information to obtain the initial acceleration of the object under vibration, making full use of both wavelength and phase information of the phase-shift peaks, resulting in a more accurate initial acceleration. The wavelength position of the Bragg grating resonant peak sideband is obtained using an optical accelerometer, and the ambient temperature is analyzed using a temperature sideband drift function based on the wavelength position, realizing the sensor's own temperature self-sensing. A temperature drift compensation model is constructed, and correction coefficients are analyzed based on the target ambient temperature using the temperature drift compensation model. The initial acceleration is calibrated based on the target correction coefficient to obtain the target acceleration of the measured object. This avoids the occurrence of compensation errors, significantly reduces cross-interference caused by temperature, effectively improves the measurement accuracy of the optical accelerometer, and constructs a complete closed loop from temperature measurement to acceleration correction. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic flowchart of the measurement method of the optical accelerometer in an embodiment of the present invention; Figure 2 This is a flowchart illustrating the measurement method of an optical accelerometer according to another embodiment of the present invention; Figure 3 This is a schematic diagram of the structural composition of the optical accelerometer measurement system in an embodiment of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 Please see Figure 1 , Figure 1 This is a flowchart illustrating the measurement method of an optical accelerometer according to an embodiment of the present invention. The method includes: S11: Obtain the first reflection spectrum of the phase-shifted Bragg grating of the object under test in the absence of vibration based on the optical accelerometer, and determine the wavelength position of the first phase-shifted peak based on the first reflection spectrum; In the specific implementation of this invention, the first reflection spectrum of the phase-shifted Bragg grating of the measured object under vibration-free conditions is obtained based on the optical accelerometer. A Fourier transform is performed on the first reflection spectrum to obtain spatial frequency domain information, and characteristic frequency components are determined based on the spatial frequency domain information. An inverse Fourier transform is performed based on the characteristic frequency components to obtain spectral profile information, and the center wavelength of the phase-shifted peak energy distribution is analyzed based on the spectral profile information. The wavelength position of the first phase-shifted peak is determined based on the center wavelength. This eliminates the influence of individual sensor differences and initial conditions on the measurement results, making the acceleration calculation repeatable and interchangeable.

[0019] S12: Based on the optical accelerometer, the second reflection spectrum of the phase-shifted Bragg grating of the measured object under external vibration is obtained, and the wavelength position of the second phase-shifted peak is determined based on the second reflection spectrum, and the phase change information is determined based on the second reflection spectrum; In the specific implementation of this invention, the second reflection spectrum of the phase-shifted Bragg grating of the measured object under external vibration is obtained based on the optical accelerometer, and the wavelength position of the second phase-shift peak is determined based on the second reflection spectrum. The first interference sideband region is analyzed based on the first reflection spectrum, and the spectral abscissa is mapped based on the first interference sideband region to obtain the first interferogram. The second interference sideband region is analyzed based on the second reflection spectrum, and the spectral abscissa is mapped based on the second interference sideband region to obtain the second interferogram. The static reference phase is determined based on the first interferogram, the instantaneous phase is determined based on the second interferogram, and the phase change information is obtained by differential operation based on the static reference phase and the instantaneous phase. The phase information is used to improve the detection sensitivity of low-frequency or small vibrations and provide original dynamic data for high-precision initial acceleration calculation.

[0020] S13: Based on the wavelength positions of the first phase shift peak, the second phase shift peak, and the phase change information, perform acceleration analysis to obtain the initial acceleration of the object under test; In the specific implementation of this invention, the wavelength shift is determined based on the wavelength positions of the first and second phase shift peaks, and the wavelength shift is converted using a preset strain-wavelength conversion coefficient to obtain the average axial strain change of the optical fiber; the coarse acceleration value is determined based on the average axial strain change of the optical fiber; the phase change information is unwrapped to obtain the phase time history, and the cavity length displacement is determined based on the phase time history; the second-order numerical differentiation is performed based on the cavity length displacement to obtain the fine acceleration component; acceleration analysis is performed based on the coarse acceleration value and the fine acceleration component to obtain the initial acceleration of the measured object, making full use of the wavelength and phase information of the phase shift peaks to improve the accuracy of the initial acceleration.

[0021] S14: Obtain the wavelength position of the Bragg grating resonance peak sideband based on the optical accelerometer, and perform ambient temperature analysis based on the wavelength position using the temperature sideband drift function to obtain the target ambient temperature; In the specific implementation of this invention, the wavelength position of the Bragg grating resonant peak sideband is obtained based on an optical accelerometer, and a temperature sideband drift function is constructed; the target reflected light power at the wavelength position is determined, and the target reflected light power is filtered to obtain the filtered target reflected light power; the light power ratio is analyzed based on the filtered target reflected light power, and the ambient temperature is analyzed using the temperature sideband drift function based on the light power ratio to obtain the target ambient temperature, providing an accurate ambient temperature value for subsequent temperature compensation.

[0022] S15: Construct a temperature drift compensation model, perform correction coefficient analysis based on the target ambient temperature using the temperature drift compensation model to obtain the target correction coefficient, and calibrate the initial acceleration based on the target correction coefficient to obtain the target acceleration of the measured object.

[0023] In the specific implementation of this invention, a temperature-varying grating parameter layer is constructed; the storage modulus and loss factor of the material sample of the optical accelerometer are obtained within the operating temperature range, and the stiffness reduction coefficient at each temperature point is analyzed based on the storage modulus; the temperature-varying relationship of the structural damping factor is determined based on the loss factor, and a phase shift correction library is constructed based on the temperature-varying relationship; a mechanical parameter temperature-varying layer is constructed based on the phase shift correction library and the stiffness reduction coefficient at each temperature point; the wavelength splitting amount of the orthogonal polarization eigenmode corresponding to the phase shift peak in the reflection spectrum of the phase-shifted Bragg grating at different temperatures is obtained, and a relationship curve is constructed based on the wavelength splitting amount and the corresponding temperature point; a cross-sensitive decoupling layer is constructed based on the relationship curve, and a mechanical parameter temperature-varying layer is constructed based on the grating parameter temperature-varying layer and the mechanical parameter temperature-varying layer. A temperature drift compensation model is constructed using a temperature-varying parameter layer and a cross-sensitive decoupling layer. The target ambient temperature is input into the temperature drift compensation model, which outputs a sensitivity temperature scaling factor, a phase strain compensation factor, a stiffness reduction factor, a dynamic response correction function, and a polarization coupling perturbation correction factor. Based on the sensitivity temperature scaling factor, phase strain compensation factor, stiffness reduction factor, dynamic response correction function, and polarization coupling perturbation correction factor, a weighted fusion is performed to obtain a target correction factor. The initial acceleration is calibrated based on this target correction factor to obtain the target acceleration of the measured object. This ensures that the final acceleration output reflects the actual vibration state of the measured object and meets the stringent temperature robustness requirements of industrial environments and precision measurements.

[0024] In this embodiment of the invention, the first reflection spectrum of the phase-shifted Bragg grating of the object under vibration-free conditions is obtained using an optical accelerometer to determine the wavelength position of the first phase-shift peak; the second reflection spectrum of the phase-shifted Bragg grating of the object under external vibration conditions is obtained using an optical accelerometer to determine the wavelength position of the second phase-shift peak, and the phase change information is determined based on the second reflection spectrum; acceleration analysis is performed based on the wavelength positions of the first and second phase-shift peaks and the phase change information to obtain the initial acceleration of the object under vibration, making full use of both wavelength and phase information of the phase-shift peaks, resulting in a more accurate initial acceleration. The wavelength position of the Bragg grating resonant peak sideband is obtained using an optical accelerometer, and the ambient temperature is analyzed using a temperature sideband drift function based on the wavelength position, realizing the sensor's own temperature self-sensing. A temperature drift compensation model is constructed, and correction coefficients are analyzed based on the target ambient temperature using the temperature drift compensation model. The initial acceleration is calibrated based on the target correction coefficient to obtain the target acceleration of the measured object. This avoids the occurrence of compensation errors, significantly reduces cross-interference caused by temperature, effectively improves the measurement accuracy of the optical accelerometer, and constructs a complete closed loop from temperature measurement to acceleration correction.

[0025] Example 2 Please see Figure 2 , Figure 2 This is a flowchart illustrating a measurement method using an optical accelerometer according to another embodiment of the present invention, the method comprising: S201: Obtain the first reflection spectrum of the phase-shifted Bragg grating of the object under test in the absence of vibration based on the optical accelerometer, and determine the wavelength position of the first phase-shifted peak based on the first reflection spectrum; In a specific implementation of the present invention, determining the wavelength position of the first phase shift peak based on the first reflection spectrum includes: performing a Fourier transform on the first reflection spectrum to obtain spatial frequency domain information, and determining characteristic frequency components based on the spatial frequency domain information; performing an inverse Fourier transform on the characteristic frequency components to obtain spectral profile information, and analyzing the center wavelength of the phase shift peak energy distribution based on the spectral profile information; and determining the wavelength position of the first phase shift peak based on the center wavelength.

[0026] Specifically, the first reflection spectrum of the phase-shifted Bragg grating of the tested object under vibration-free conditions is obtained based on an optical accelerometer. This optical accelerometer integrates a novel composite structure of a fiber Fabry-Perot and a fiber Bragg grating. The phase-shifted Bragg grating formed by this composite structure is used to detect external vibration signals. This composite structure is created by first etching a uniform periodic Bragg grating in the core of a single-mode fiber using femtosecond laser point-by-point writing technology. Then, two local refractive index abrupt change points spaced several micrometers apart are introduced in the central region of the Bragg grating to construct a miniature Fabry-Perot interferometer cavity. This miniature Fabry-Perot interferometer cavity acts as a precise phase jump defect in the periodic refractive index modulation distribution of the Bragg grating, thus forming a phase-shifted Bragg grating with an extremely narrow transmission window. Under the condition that the tested object is completely stationary and free from any external vibration interference, a narrow-linewidth tunable laser is used to perform high-resolution wavelength scanning on the phase-shifted Bragg grating. Simultaneously, a high-sensitivity photodetector is used to synchronously collect the reflected light intensity, obtaining a set of discrete wavelength-to-reflected light intensity data, which constitutes the first reflection spectrum.

[0027] A Fourier transform is performed on the first reflection spectrum to obtain spatial frequency domain information. The Fourier transform converts the first reflection spectrum from the wavelength domain to the spatial frequency domain. Based on the spatial frequency domain information, characteristic frequency components are determined. Based on the unique interference envelope frequency introduced by the miniature Fabry-Perot interferometer cavity in the composite structure and the characteristic frequency components generated by the phase jump defect, a digital bandpass filter is designed to filter out the fundamental frequency component originating from the uniform Bragg grating and the low-frequency noise formed by stray reflections from the fiber optic link, while retaining the characteristic frequency components generated by the phase jump defect.

[0028] Based on the characteristic frequency components, an inverse Fourier transform is performed to obtain spectral profile information. This involves converting the characteristic frequency components from the spatial frequency domain to the wavelength domain, reconstructing a spectral profile without background tilt and containing only a pure line shape of the phase-shift peak. Based on this spectral profile information, the center wavelength of the phase-shift peak energy distribution is analyzed. Using the local minima and global statistical characteristics of the spectral profile as references, an intensity threshold located at the half-height of the phase-shift peak is generated. Within the spectral range above the intensity threshold, the reflected light intensity at each wavelength point is considered as a weighting factor for the energy distribution. Energy centroid calculation is then performed, i.e., traversing all discrete wavelength points within this range, accumulating the product of the wavelength value and the corresponding intensity value, and then dividing by the accumulated total intensity value. The resulting weighted average wavelength is the center wavelength of the phase-shift peak energy distribution, and this center wavelength is determined as the wavelength position of the first phase-shift peak.

[0029] S202: Based on the optical accelerometer, the second reflection spectrum of the phase-shifted Bragg grating of the measured object under external vibration is obtained, and the wavelength position of the second phase-shifted peak is determined based on the second reflection spectrum, and the phase change information is determined based on the second reflection spectrum; In a specific implementation of this invention, determining the phase change information based on the second reflection spectrum includes: analyzing the first interference sideband region based on the first reflection spectrum, and mapping the spectral abscissa based on the first interference sideband region to obtain a first interferogram; analyzing the second interference sideband region based on the second reflection spectrum, and mapping the spectral abscissa based on the second interference sideband region to obtain a second interferogram; determining the static reference phase based on the first interferogram, determining the instantaneous phase based on the second interferogram, and performing a difference operation based on the static reference phase and the instantaneous phase to obtain the phase change information.

[0030] Specifically, the second reflection spectrum of the phase-shifted Bragg grating of the measured object under external vibration is obtained based on an optical accelerometer. When the measured object is excited by external vibration, the sensitive mass block inside the optical accelerometer undergoes a slight displacement under the action of inertial force, directly stretching or compressing the composite structure rigidly connected to the sensitive mass block, causing dynamic changes in the Bragg grating period and the cavity length of the miniature Fabry-Perot interferometer cavity. A dual-channel synchronous acquisition mechanism is adopted: in the first channel, a tunable laser maintains a rapid wavelength scan to acquire the instantaneous reflection spectrum of the phase-shifted peak region, which is the second reflection spectrum. The wavelength position of the second phase-shifted peak is determined based on the second reflection spectrum. The analysis method for the wavelength position of the second phase-shifted peak is the same as that for the first phase-shifted peak, and will not be repeated here.

[0031] Based on the first reflection spectrum, the first interference sideband region is analyzed, that is, the fine wavy interference sideband region generated by the modulation of the micro Fabry-Perot interferometer cavity on both sides of the phase shift peak is extracted from the second reflection spectrum. Based on the first interference sideband region, the spectral abscissa is mapped to obtain the first interferogram. Based on the first interference sideband region, the spectral abscissa is linearly mapped from wavelength to the equivalent wavenumber space to obtain an approximately equiperiodic interferogram, which is the first interferogram.

[0032] The second interference sideband region is analyzed based on the second reflection spectrum, and the spectral abscissa is mapped based on the second interference sideband region to obtain the second interferogram. The acquisition methods of the second interference sideband region and the second interferogram are the same as those of the first interference sideband region and the first interferogram.

[0033] Based on the first interferogram, a static reference phase is determined. A Hilbert transform is performed on the first interferogram to extract the static reference phase. Based on the second interferogram, an instantaneous phase is determined. A Hilbert transform is also performed on the second interferogram to extract the instantaneous phase. A difference operation is performed on the static reference phase and the instantaneous phase to obtain phase change information. A phase unwrapping operation is then applied to eliminate ambiguity, obtaining continuous information directly corresponding to the length variation of the micro Fabry-Perot interferometer cavity. This continuous information is the phase change information.

[0034] S203: Based on the wavelength positions of the first phase shift peak, the second phase shift peak, and the phase change information, perform acceleration analysis to obtain the initial acceleration of the object under test; In the specific implementation of this invention, the step of performing acceleration analysis based on the wavelength positions of the first and second phase shift peaks and phase change information to obtain the initial acceleration of the object under test includes: determining the wavelength shift based on the wavelength positions of the first and second phase shift peaks, and performing conversion processing based on the wavelength shift using a preset strain-wavelength conversion coefficient to obtain the average axial strain change of the optical fiber; determining a coarse acceleration value based on the average axial strain change of the optical fiber; performing phase unwrapping on the phase change information to obtain the phase time history, and determining the cavity length displacement based on the phase time history, performing second-order numerical differentiation based on the cavity length displacement to obtain the fine acceleration component; and performing acceleration analysis based on the coarse acceleration value and the fine acceleration component to obtain the initial acceleration of the object under test.

[0035] Specifically, the wavelength shift is determined based on the wavelength positions of the first and second phase shift peaks. The wavelength shift is obtained by subtracting the wavelength positions of the second and first phase shift peaks. Based on this wavelength shift, a preset strain-wavelength conversion coefficient is used to convert the wavelength shift into the average axial strain change of the fiber. Finally, using a pre-calibrated strain-wavelength conversion coefficient of the fiber Bragg grating, the wavelength shift is converted into the average axial strain change of the fiber.

[0036] The coarse acceleration value is determined based on the average axial strain change of the optical fiber. Based on the average axial strain change of the optical fiber, and according to the mechanical transmission model of the sensitive mass block and the elastic support structure inside the optical accelerometer, it is converted into the displacement of the sensitive mass block relative to the base. The acceleration sequence is obtained by performing a second differential on the displacement. Then, a low-pass filter is applied to output the primary coarse acceleration value covering a large dynamic range.

[0037] Phase unwrapping is performed on the phase change information to obtain the phase time history. By detecting phase jumps between adjacent sampling points and applying compensation at integer multiples of the period, abrupt changes caused by the periodic entanglement of the interference phase are eliminated, resulting in a phase time history that changes continuously and monotonically on the time axis. Based on this phase time history, the cavity length displacement is determined. Using the known linear transformation relationship between the cavity length change and phase change of the miniature Fabry-Perot interferometer cavity, the phase value at each moment is converted into the corresponding cavity length expansion / contraction, forming a cavity length displacement sequence reflecting the fine displacement at the connection point between the sensitive mass block and the optical fiber. Second-order numerical differentiation is performed based on the cavity length displacement. Using a bandpass filter with an adjustable center frequency, high-frequency dynamic components directly related to the vibration excitation are extracted from the differentiation results, obtaining fine acceleration components capable of characterizing minute instantaneous changes in acceleration.

[0038] Acceleration analysis is performed based on the coarse acceleration measurement and the fine acceleration components to obtain the initial acceleration of the object under test. Time-frequency analysis is then performed on the coarse acceleration measurement and the fine acceleration components to obtain their respective time-varying power spectra. Based on the time-varying power spectra corresponding to the coarse acceleration measurement and the fine acceleration components, weighting coefficients are automatically assigned within each time window according to the local signal-to-noise ratio and sensitivity boundaries. The coarse acceleration measurement is given a larger weight in the low-frequency band, and the fine acceleration components are given a larger weight in the high-frequency band. The mid-frequency band is fused using a transition strategy of coherent superposition and cross-attenuation to obtain the weighted fused spectrum. Based on the weighted fused spectrum, the time-domain acceleration signal is reconstructed through inverse transformation. This time-domain acceleration signal is the initial acceleration of the object under test.

[0039] S204: Obtain the wavelength position of the Bragg grating resonance peak sideband based on the optical accelerometer, and perform ambient temperature analysis based on the wavelength position using the temperature sideband drift function to obtain the target ambient temperature; In a specific implementation of this invention, the step of analyzing the ambient temperature based on the wavelength position using a temperature sideband drift function to obtain the target ambient temperature includes: constructing a temperature sideband drift function; determining the target reflected light power at the wavelength position and filtering the target reflected light power to obtain the filtered target reflected light power; analyzing the light power ratio based on the filtered target reflected light power, and analyzing the ambient temperature based on the light power ratio using the temperature sideband drift function to obtain the target ambient temperature.

[0040] Specifically, based on the wavelength position of the Bragg grating resonant peak sideband obtained by the optical accelerometer, the region with the largest linear slope and smallest curvature on the short-wavelength side of the main resonant peak of the Bragg grating in the composite structure is selected as the temperature sensing sideband. Two narrow-linewidth lasers are selected, and their output wavelengths are aligned with pre-marked upper and lower reference wavelength positions on the temperature sensing sideband, respectively. The two laser beams are injected into the composite structure through a coupler. At the reflection end, a wave demultiplexer is used to separate the reflected light at the upper and lower reference wavelength positions, which are then received by two independent photodetectors. The reflected light power corresponding to the upper and lower reference wavelength positions is recorded in real time. The upper and lower reference wavelength positions constitute the wavelength position of the Bragg grating resonant peak sideband. The temperature sideband drift function is constructed by obtaining the first reflected light power corresponding to the upper reference wavelength position and the second reflected light power corresponding to the lower reference wavelength position during the experiment of the optical accelerometer at each temperature step.

[0041] The target reflected light power at the wavelength position is determined, that is, the reflected light power corresponding to the upper reference wavelength position and the reflected light power corresponding to the lower reference wavelength position are determined, and the target reflected light power is filtered, that is, the two optical power signals are subjected to digital low-pass filtering or sliding window averaging with extremely low cutoff frequency to filter out the instantaneous sideband jitter caused by vibration and retain the slowly varying components caused by temperature change, thereby obtaining the filtered target reflected light power.

[0042] The optical power ratio is analyzed based on the filtered target reflected light power. Specifically, the ratio between the reflected light power at the upper reference wavelength position and the reflected light power at the lower reference wavelength position is calculated. Based on this ratio, the ambient temperature is analyzed using the temperature sideband drift function to obtain the target ambient temperature. The optical power ratio is input into the temperature sideband drift function, and linear or spline interpolation is performed in the currently stored ratio-temperature inverse table to directly resolve the current temperature value. If the optical power ratio is within the calibration range, the resolved temperature is directly output. If the optical power ratio exceeds the calibration boundary due to extreme conditions, an extrapolation estimate is performed using the fitting polynomial of the temperature sideband drift function, and an extrapolation confidence flag is attached to the extrapolated estimate. The resolved current temperature value is the target ambient temperature.

[0043] Furthermore, the construction of the temperature sideband drift function includes: acquiring the first reflected light power corresponding to the upper reference wavelength position and the second reflected light power corresponding to the lower reference wavelength position during the experiment of the optical accelerometer at each temperature step; calculating the target ratio of the first reflected light power and the second reflected light power; generating a temperature-light power ratio data point sequence based on the target ratio and the temperature step, and performing curve fitting on the temperature-light power ratio data point sequence to obtain a continuous mapping curve; and determining the temperature sideband drift function based on the continuous mapping curve.

[0044] Specifically, during the experiment at each temperature step, the first reflected optical power at the upper reference wavelength position and the second reflected optical power at the lower reference wavelength position were obtained. On a constant-temperature calibration platform, the composite structure of the optical accelerometer was placed in a programmable temperature-controlled chamber. The temperature was set to gradually increase from the lower limit of the measurement range to the upper limit in increments not exceeding 0.1 degrees Celsius, maintaining this temperature for a sufficient duration at each temperature step to ensure thermal equilibrium was reached within the optical fiber. At each temperature step, the reflected optical power at the upper reference wavelength position and the reflected optical power at the lower reference wavelength position were simultaneously recorded during the experiment. The target ratio of the first reflected optical power to the second reflected optical power was calculated.

[0045] Based on the target ratio and temperature steps, a temperature-optical power ratio data point sequence is generated. This sequence iterates through all temperature steps, forming a temperature-optical power ratio data point sequence based on each temperature step and its corresponding target ratio. Curve fitting is then performed on this temperature-optical power ratio data point sequence to obtain a continuous mapping curve. Piecewise cubic spline interpolation or higher-order polynomial fitting can be used to generate a smooth and strictly monotonic continuous mapping curve, which is the temperature sideband drift function. Simultaneously, the temperature sideband drift function can be stored in the signal processing unit's memory in the form of a lookup table, and its inverse function lookup table or inverse interpolation algorithm can be generated for online real-time calculation.

[0046] S205: Constructing a thermochromic grating parameter layer; In a specific implementation of this invention, the construction of the grating parameter temperature-varying layer includes: obtaining the thermo-optic coefficient and thermal expansion coefficient of the material sample of the optical accelerometer in the measurement temperature region, and constructing a sensitivity temperature scaling factor table based on the thermo-optic coefficient and thermal expansion coefficient; obtaining the phase temperature change information of the reference optical fiber in the measurement temperature region, and determining the phase strain compensation factor change curve based on the phase temperature change information; and constructing the grating parameter temperature-varying layer based on the sensitivity temperature scaling factor table and the phase strain compensation factor change curve.

[0047] Specifically, the thermo-optic coefficient and thermal expansion coefficient of the material sample of the optical accelerometer are obtained within the measurement temperature range. The fiber material used in the Bragg grating and the miniature Fabry-Perot interferometer in the composite structure of the optical accelerometer is used as a standard material sample. The precise values ​​of its thermo-optic coefficient and thermal expansion coefficient within the measurement temperature range are determined using a thermo-optic coefficient measuring device and a thermal dilatometer. A sensitivity temperature scaling factor table is constructed based on these thermo-optic coefficients and thermal expansion coefficients. Based on the measured thermo-optic coefficients and thermal expansion coefficients, and according to coupled-mode theory and the Fabry-Perot cavity phase condition, the functional relationship between fiber strain-wavelength shift sensitivity and temperature under unit acceleration is calculated. A sensitivity temperature scaling factor table indexed by temperature is then generated based on this functional relationship.

[0048] To obtain the phase temperature change information of the reference fiber in the measurement temperature region, a section of reference fiber containing only a miniature Fabry-Perot interferometer cavity and decoupled from strain is placed in the same measurement temperature region. By precisely measuring the change of the interference phase with temperature, the phase temperature change information of the reference fiber in the measurement temperature region is obtained. Based on the phase temperature change information, the phase strain compensation factor variation curve is determined. The independent influence of refractive index thermal change on the phase-strain conversion coefficient is separated according to the phase temperature change information, generating a correction curve of the phase-strain compensation factor as a function of temperature, which is the phase strain compensation factor variation curve.

[0049] Based on the sensitivity temperature scaling factor table and the phase strain compensation factor variation curve, a temperature-varying grating parameter layer is constructed. The sensitivity temperature scaling factor table and the phase strain compensation factor variation curve are then integrated to form the complete output of the temperature-varying grating parameter layer.

[0050] S206: Obtain the storage modulus and loss factor of the material sample of the optical accelerometer within the operating temperature range, and analyze the stiffness reduction factor at each temperature point based on the storage modulus. In the specific implementation of this invention, the energy storage modulus and loss factor of the material sample of the optical accelerometer are obtained within the operating temperature range. Based on the energy storage modulus, the stiffness reduction coefficient at each temperature point is analyzed. Material samples identical to the sensitive mass block and cantilever beam structure inside the optical accelerometer are disassembled and subjected to frequency sweep excitation at different frequencies within the operating temperature range using a dynamic mechanical analyzer. The energy storage modulus and loss factor are accurately measured. The energy storage modulus is converted into the structural stiffness of the cantilever beam, and the stiffness reduction coefficient at each temperature point is calculated based on the stiffness value at room temperature.

[0051] S207: Determine the temperature variation relationship of the structural damping factor based on the loss factor, construct a phase shift correction library based on the temperature variation relationship, and construct a mechanical parameter temperature variation layer based on the phase shift correction library and the stiffness reduction coefficient at each temperature point. In the specific implementation of this invention, the temperature-dependent relationship of the structural damping factor is determined based on the loss factor. A phase shift correction library is constructed based on this temperature-dependent relationship; that is, the temperature-dependent relationship of the structural damping factor is derived from the loss factor curve, and a correction library for the amplitude and phase shift of the acceleration frequency response function at different temperatures is constructed. A temperature-dependent layer of mechanical parameters is constructed based on the phase shift correction library and the stiffness reduction coefficient at each temperature point. Micro-samples containing fiber coating and encapsulating colloid are cut from the encapsulated composite structure, and stress transfer efficiency calibration experiments are conducted under temperature control. A known strain is applied to the fiber, and the ratio of the actual strain response to the theoretical strain of the Bragg grating and the micro Fabry-Perot interferometer cavity is measured to obtain the variation law of stress transfer efficiency with temperature. This variation law is fitted into an empirical correction coefficient, which is incorporated into the correction amount for strain distribution drift and combined with the stiffness reduction coefficient to constitute the output of the temperature-dependent layer of mechanical parameters.

[0052] S208: Obtain the wavelength splitting amount of the phase shift peak corresponding to the orthogonal polarization intrinsic mode in the reflection spectrum of the phase-shifted Bragg grating at different temperatures, and construct a relationship curve based on the wavelength splitting amount and the corresponding temperature point; In the specific implementation of this invention, the wavelength splitting amount of the phase shift peaks corresponding to the orthogonal polarization eigenmodes in the reflection spectrum of the phase-shifted Bragg grating at different temperatures is obtained. The composite structure is fixed in the polarization state analysis optical path. Under precise temperature control, a polarization controller is used to scan the polarization state of the input light, and a spectrometer is used to record the wavelength splitting amount of the phase shift peaks corresponding to the two orthogonal polarization eigenmodes in the reflection spectrum of the phase-shifted Bragg grating at different temperatures. Based on the wavelength splitting amount and the corresponding temperature points, a relationship curve is constructed. By analyzing the change data of wavelength splitting amount with temperature, a polarization wavelength splitting amount-temperature relationship curve is established.

[0053] S209: Construct a cross-sensitive decoupling layer based on the relationship curve, and construct a temperature drift compensation model based on the grating parameter temperature-varying layer, the mechanical parameter temperature-varying layer, and the cross-sensitive decoupling layer. Analyze the correction coefficients using the temperature drift compensation model based on the target ambient temperature to obtain the target correction coefficients. Then, calibrate the initial acceleration based on the target correction coefficients to obtain the target acceleration of the measured object.

[0054] In the specific implementation of this invention, the step of performing correction coefficient analysis based on the target ambient temperature using the temperature drift compensation model to obtain the target correction coefficient includes: inputting the target ambient temperature into the temperature drift compensation model, outputting a sensitivity temperature scaling factor, a phase strain compensation factor, a stiffness reduction factor, a dynamic response correction function, and a polarization coupling perturbation correction coefficient; and performing weighted fusion based on the sensitivity temperature scaling factor, phase strain compensation factor, stiffness reduction factor, dynamic response correction function, and polarization coupling perturbation correction coefficient to obtain the target correction coefficient.

[0055] Specifically, a cross-sensitive decoupling layer is constructed based on the aforementioned relationship curve. A table showing the variation of the polarization coupling perturbation correction coefficient with temperature is calculated based on the relationship curve. This coefficient is used to compensate for the cross-sensitive errors in wavelength and phase detection caused by thermal stress birefringence. For potentially higher-order perturbation terms, a secondary correction is performed using finite element thermal stress simulation combined with measured data, resulting in the final polarization state-related correction factor output. A temperature drift compensation model is constructed based on the aforementioned grating parameter temperature-varying layer, mechanical parameter temperature-varying layer, and cross-sensitive decoupling layer; that is, the drift compensation model consists of the grating parameter temperature-varying layer, mechanical parameter temperature-varying layer, and cross-sensitive decoupling layer.

[0056] The target ambient temperature is input into the temperature drift compensation model, which outputs the sensitivity temperature scaling factor, phase strain compensation factor, stiffness reduction factor, dynamic response correction function, and polarization coupling perturbation correction factor. The temperature drift compensation model takes the target ambient temperature as input and outputs the sensitivity temperature scaling factor, phase strain compensation factor, stiffness reduction factor, dynamic response correction function, and polarization coupling perturbation correction factor through three-layer parallel operation.

[0057] The target correction coefficient is obtained by weighted fusion based on the sensitivity temperature scaling factor, phase strain compensation factor, stiffness reduction factor, dynamic response correction function, and polarization coupling perturbation correction coefficient. Specifically, the target correction coefficient is calculated by weighted summation based on the sensitivity temperature scaling factor, phase strain compensation factor, stiffness reduction factor, dynamic response correction function, and polarization coupling perturbation correction coefficient and their weights. The weights can be matched in the database.

[0058] The initial acceleration is calibrated based on the target correction coefficient to obtain the target acceleration of the measured object. The time history signal of the initial acceleration is synchronized with the target ambient temperature on the time axis. The amplitude of the initial acceleration is multiplied by the amplitude correction component contained in the target correction coefficient to obtain the amplitude-corrected acceleration signal. The amplitude-corrected acceleration signal is converted into the frequency domain through Fourier transform. Based on the dynamic response correction function contained in the target correction coefficient, the amplitude and phase of each frequency component are finely reshaped to compensate for the frequency response distortion caused by temperature changes, resulting in a frequency-domain compensated acceleration signal. The frequency-domain compensated acceleration signal is then converted back to the time domain through inverse Fourier transform, outputting the acceleration signal after eliminating the influence of ambient temperature. This acceleration signal is the target acceleration of the measured object.

[0059] In this embodiment of the invention, the first reflection spectrum of the phase-shifted Bragg grating of the object under vibration-free conditions is obtained using an optical accelerometer to determine the wavelength position of the first phase-shift peak; the second reflection spectrum of the phase-shifted Bragg grating of the object under external vibration conditions is obtained using an optical accelerometer to determine the wavelength position of the second phase-shift peak, and the phase change information is determined based on the second reflection spectrum; acceleration analysis is performed based on the wavelength positions of the first and second phase-shift peaks and the phase change information to obtain the initial acceleration of the object under vibration, making full use of both wavelength and phase information of the phase-shift peaks, resulting in a more accurate initial acceleration. The wavelength position of the Bragg grating resonant peak sideband is obtained using an optical accelerometer, and the ambient temperature is analyzed using a temperature sideband drift function based on the wavelength position, realizing the sensor's own temperature self-sensing. A temperature drift compensation model is constructed, and correction coefficients are analyzed based on the target ambient temperature using the temperature drift compensation model. The initial acceleration is calibrated based on the target correction coefficient to obtain the target acceleration of the measured object. This avoids the occurrence of compensation errors, significantly reduces cross-interference caused by temperature, effectively improves the measurement accuracy of the optical accelerometer, and constructs a complete closed loop from temperature measurement to acceleration correction.

[0060] Example 3 Please see Figure 3 , Figure 3 This is a schematic diagram of the structural composition of the optical accelerometer measurement system in an embodiment of the present invention. The system includes: First information analysis module 31: used to acquire the first reflection spectrum of the phase-shifted Bragg grating of the object under test in the absence of vibration based on the optical accelerometer, and to determine the wavelength position of the first phase-shifted peak based on the first reflection spectrum; The second information analysis module 32 is used to acquire the second reflection spectrum of the phase-shifted Bragg grating of the measured object under external vibration based on the optical accelerometer, and to determine the wavelength position of the second phase-shifted peak based on the second reflection spectrum, and to determine the phase change information based on the second reflection spectrum. Initial acceleration module 33: used to perform acceleration analysis based on the wavelength position of the first phase shift peak, the wavelength position of the second phase shift peak, and phase change information to obtain the initial acceleration of the object under test; Ambient temperature analysis module 34: used to obtain the wavelength position of the Bragg grating resonance peak sideband based on the optical accelerometer, and to perform ambient temperature analysis based on the wavelength position using the temperature sideband drift function to obtain the target ambient temperature; Correction module 35: Used to construct a temperature drift compensation model, perform correction coefficient analysis based on the target ambient temperature using the temperature drift compensation model to obtain the target correction coefficient, and calibrate the initial acceleration based on the target correction coefficient to obtain the target acceleration of the measured object.

[0061] In the specific implementation of this invention, the specific implementation methods of the system items can be referred to the implementation methods of the above-mentioned method items, and will not be repeated here.

[0062] In this embodiment of the invention, the first reflection spectrum of the phase-shifted Bragg grating of the object under vibration-free conditions is obtained using an optical accelerometer to determine the wavelength position of the first phase-shift peak; the second reflection spectrum of the phase-shifted Bragg grating of the object under external vibration conditions is obtained using an optical accelerometer to determine the wavelength position of the second phase-shift peak, and the phase change information is determined based on the second reflection spectrum; acceleration analysis is performed based on the wavelength positions of the first and second phase-shift peaks and the phase change information to obtain the initial acceleration of the object under vibration, making full use of both wavelength and phase information of the phase-shift peaks, resulting in a more accurate initial acceleration. The wavelength position of the Bragg grating resonant peak sideband is obtained using an optical accelerometer, and the ambient temperature is analyzed using a temperature sideband drift function based on the wavelength position, realizing the sensor's own temperature self-sensing. A temperature drift compensation model is constructed, and correction coefficients are analyzed based on the target ambient temperature using the temperature drift compensation model. The initial acceleration is calibrated based on the target correction coefficient to obtain the target acceleration of the measured object. This avoids the occurrence of compensation errors, significantly reduces cross-interference caused by temperature, effectively improves the measurement accuracy of the optical accelerometer, and constructs a complete closed loop from temperature measurement to acceleration correction.

[0063] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, etc.

[0064] Furthermore, the measurement method and system of an optical accelerometer provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A measurement method for an optical accelerometer, characterized in that, The method includes: The first reflection spectrum of the phase-shifted Bragg grating of the object under test is obtained by an optical accelerometer under vibration-free conditions, and the wavelength position of the first phase-shifted peak is determined based on the first reflection spectrum. The second reflection spectrum of the phase-shifted Bragg grating of the measured object under external vibration is obtained by an optical accelerometer, and the wavelength position of the second phase-shifted peak is determined based on the second reflection spectrum, and the phase change information is determined based on the second reflection spectrum. Acceleration analysis is performed based on the wavelength positions of the first and second phase shift peaks and phase change information to obtain the initial acceleration of the object under test. The wavelength position of the Bragg grating resonance peak sideband is obtained by using an optical accelerometer, and the ambient temperature is analyzed using the temperature sideband drift function based on the wavelength position to obtain the target ambient temperature. A temperature drift compensation model is constructed. Based on the target ambient temperature, the temperature drift compensation model is used to perform correction coefficient analysis to obtain the target correction coefficient. Based on the target correction coefficient, the initial acceleration is calibrated to obtain the target acceleration of the measured object.

2. The measurement method of the optical accelerometer according to claim 1, characterized in that, Determining the wavelength position of the first phase shift peak based on the first reflection spectrum includes: Perform a Fourier transform on the first reflection spectrum to obtain spatial frequency domain information, and determine the characteristic frequency components based on the spatial frequency domain information; Inverse Fourier transform is performed based on the characteristic frequency components to obtain spectral profile information, and the center wavelength of the phase shift peak energy distribution is analyzed based on the spectral profile information. The wavelength position of the first phase shift peak is determined based on the center wavelength.

3. The measurement method of the optical accelerometer according to claim 1, characterized in that, The determination of phase change information based on the second reflectance spectrum includes: The first interference sideband region is analyzed based on the first reflection spectrum, and the spectral abscissa is mapped based on the first interference sideband region to obtain the first interferogram; The second interference sideband region is analyzed based on the second reflection spectrum, and the spectral abscissa is mapped based on the second interference sideband region to obtain the second interferogram; The static reference phase is determined based on the first interferogram, the instantaneous phase is determined based on the second interferogram, and a differential operation is performed based on the static reference phase and the instantaneous phase to obtain phase change information.

4. The measurement method of the optical accelerometer according to claim 1, characterized in that, The acceleration analysis based on the wavelength positions of the first and second phase shift peaks and phase change information to obtain the initial acceleration of the object under test includes: The wavelength shift is determined based on the wavelength positions of the first and second phase shift peaks, and the wavelength shift is then converted using a preset strain-wavelength conversion coefficient to obtain the average axial strain change of the optical fiber. The coarse acceleration value is determined based on the average axial strain change of the optical fiber. Phase unwrapping is performed on the phase change information to obtain the phase time history, and the cavity length displacement is determined based on the phase time history. Second-order numerical differentiation is performed based on the cavity length displacement to obtain the fine acceleration components. Acceleration analysis is performed based on the coarse acceleration measurement and the fine acceleration components to obtain the initial acceleration of the object being measured.

5. The measurement method of the optical accelerometer according to claim 1, characterized in that, The step of performing environmental temperature analysis based on the wavelength position using a temperature sideband drift function to obtain the target environmental temperature includes: Construct the temperature sideband drift function; The target reflected light power at the wavelength position is determined, and the target reflected light power is filtered to obtain the filtered target reflected light power. The target ambient temperature is obtained by analyzing the optical power ratio based on the filtered target reflected light power and using the temperature sideband drift function based on the optical power ratio.

6. The measurement method of the optical accelerometer according to claim 5, characterized in that, The construction of the temperature sideband drift function includes: The first reflected light power corresponding to the upper reference wavelength position and the second reflected light power corresponding to the lower reference wavelength position were obtained during the experiment of the optical accelerometer at each temperature step. Calculate the target ratio of the first reflected light power and the second reflected light power; Based on the target ratio and temperature step, a temperature-optical power ratio data point sequence is generated, and curve fitting is performed on the temperature-optical power ratio data point sequence to obtain a continuous mapping curve; The temperature sideband drift function is determined based on the continuous mapping curve.

7. The measurement method of the optical accelerometer according to claim 1, characterized in that, The construction of the temperature drift compensation model includes: Construct a grating parameter thermochromic layer; The energy storage modulus and loss factor of the material sample of the optical accelerometer are obtained within the operating temperature range, and the stiffness reduction factor at each temperature point is analyzed based on the energy storage modulus. The temperature variation relationship of the structural damping factor is determined based on the loss factor, and a phase shift correction library is constructed based on the temperature variation relationship. A mechanical parameter temperature variation layer is constructed based on the phase shift correction library and the stiffness reduction coefficient at each temperature point. The wavelength splitting amount of the phase shift peak corresponding to the orthogonal polarization intrinsic mode in the reflection spectrum of the phase-shifted Bragg grating at different temperatures is obtained, and a relationship curve is constructed based on the wavelength splitting amount and the corresponding temperature point; A cross-sensitive decoupling layer is constructed based on the relationship curve, and a temperature drift compensation model is constructed based on the grating parameter temperature-varying layer, the mechanical parameter temperature-varying layer, and the cross-sensitive decoupling layer.

8. The measurement method of the optical accelerometer according to claim 7, characterized in that, The construction of the temperature-varying grating parameter layer includes: The thermo-optic coefficient and thermal expansion coefficient of the material sample of the optical accelerometer are obtained in the measurement temperature range, and a sensitivity temperature scaling factor table is constructed based on the thermo-optic coefficient and thermal expansion coefficient. The phase temperature change information of the reference optical fiber in the measurement temperature range is obtained, and the phase strain compensation factor change curve is determined based on the phase temperature change information. A temperature-varying grating parameter layer is constructed based on the sensitivity temperature scaling factor table and the phase strain compensation factor variation curve.

9. The measurement method of the optical accelerometer according to claim 1, characterized in that, The step of performing correction coefficient analysis based on the target ambient temperature using the temperature drift compensation model to obtain the target correction coefficient includes: The target ambient temperature is input into the temperature drift compensation model, and the output includes the sensitivity temperature scaling factor, phase strain compensation factor, stiffness reduction factor, dynamic response correction function, and polarization coupling perturbation correction factor. The target correction coefficient is obtained by weighted fusion of the sensitivity temperature scaling factor, phase strain compensation factor, stiffness reduction factor, dynamic response correction function and polarization coupling perturbation correction coefficient.

10. A measurement system for an optical accelerometer, characterized in that, The system includes: First information analysis module: used to acquire the first reflection spectrum of the phase-shifted Bragg grating of the object under test in the absence of vibration based on the optical accelerometer, and to determine the wavelength position of the first phase-shifted peak based on the first reflection spectrum; The second information analysis module is used to acquire the second reflection spectrum of the phase-shifted Bragg grating of the measured object under external vibration based on the optical accelerometer, determine the wavelength position of the second phase-shift peak based on the second reflection spectrum, and determine the phase change information based on the second reflection spectrum. Initial acceleration module: used to perform acceleration analysis based on the wavelength positions of the first phase shift peak and the second phase shift peak and phase change information to obtain the initial acceleration of the object under test; Ambient temperature analysis module: used to obtain the wavelength position of the Bragg grating resonance peak sideband based on the optical accelerometer, and to perform ambient temperature analysis based on the wavelength position using the temperature sideband drift function to obtain the target ambient temperature; Correction module: Used to construct a temperature drift compensation model, perform correction coefficient analysis based on the target ambient temperature using the temperature drift compensation model to obtain the target correction coefficient, and calibrate the initial acceleration based on the target correction coefficient to obtain the target acceleration of the measured object.

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