A polar motion measurement system and method based on high-precision fiber interferometer

Abstract

The application relates to a polar motion measurement system and method based on a high-precision fiber interferometer, which comprises multi-point distributed fiber interferometer units, a data transmission module, a data processing center and an error compensation module. Each fiber interferometer unit uses the Sagnac interference principle to monitor the change of the earth rotation angular velocity of different observation stations in real time and outputs the angular velocity data. The data processing center adopts a multi-station data joint least square method to analyze and process the collected angular velocity data, and inverses the polar motion change curve of the earth. The error compensation module monitors the system error source in real time, and based on the pre-established error compensation model, the measurement result is dynamically compensated in real time to ensure the accuracy of the measurement result. Through multi-station cooperative measurement, intelligent data joint least square inversion algorithm and real-time error model compensation, the precision and reliability of the polar motion measurement are improved, and technical support is provided for the research and application in the fields of earth science, navigation, astronomical observation and the like.

Description

Technical Field

[0001] This invention belongs to the field of geophysical measurement technology, specifically relating to a system and method for measuring Earth polar motion based on a high-precision fiber optic interferometer. Background Technology

[0002] Polar motion, the movement of the Earth's axis of rotation relative to a solid surface, is of significant research value in Earth science, navigation, astronomical observation, and many other fields. Traditional measurement methods, such as Very Long Baseline Interferometry (VLBI) and Global Navigation Satellite Systems (GNSS), while widely used, suffer from limitations in equipment complexity, high cost, and accuracy. High-precision fiber optic interferometers, with their advantages of high sensitivity, strong anti-interference capability, miniaturization, and easy integration, offer a new technical approach to measuring polar motion and demonstrate enormous application potential. Currently, the accuracy and reliability of fiber optic interferometers in polar motion measurement still need further improvement, particularly in multi-station collaborative measurement, data processing algorithms, and error compensation techniques, where optimization is still possible to fully realize their effectiveness in monitoring Earth's polar motion. Summary of the Invention

[0003] The purpose of this invention is to provide a system and method for measuring Earth's polar motion based on a high-precision fiber optic interferometer. Fiber optic interferometer units are set up at multiple different locations to monitor Earth's polar motion from multiple angles in all directions. The system uses a multi-station data joint least squares method and utilizes the angular velocity data from each observation station to identify and select the optimal combination of observation data.

[0004] The above-mentioned objectives of the present invention are mainly achieved through the following technical solutions: A system for measuring the polar motion of the Earth based on a high-precision fiber optic interferometer includes multiple fiber optic interferometer units, a data transmission module, a data processing center, and an error compensation module. Multiple fiber optic interferometer units are set up at observation stations at different geographical latitudes and longitudes to monitor the changes in angular velocity caused by the Earth's rotation in real time and output the corresponding Earth angular velocity data. The data transmission module is used to transmit the Earth's angular velocity data collected by the fiber optic interferometer unit to the data processing center; The data processing center is used to receive and process Earth's angular velocity data, and to derive the Earth's polar motion variation curve by using a joint least squares method based on multi-station data. The error compensation module is used to compensate and correct measurement errors in the fiber optic interferometer unit and the data processing center in real time.

[0005] It includes at least three fiber optic interferometer units.

[0006] The fiber optic interferometer unit includes a light source driving circuit, a self-stabilized erbium-doped fiber light source, a spectral shaping module, a nonlinear amplifier, a polarization suppressor, a Y-waveguide, a fiber ring, a fiber coupler, a detector, and a signal processing module. The light source driving circuit provides power. The light emitted from the self-stabilized erbium-doped fiber light source is split, combined, polarized, and phase-modulated by the Y-waveguide, and then passes through the fiber ring to generate a Sagnac phase difference. The spectral shaping module filters the spectrum and controls the linewidth. The nonlinear amplifier amplifies the optical signal. The polarization suppressor eliminates polarization-related noise and phase shift. The fiber coupler outputs the interference signal. The detector converts the interference signal into an electrical signal. The signal processing module processes and analyzes the electrical signal.

[0007] The signal processing module includes a time-domain filter, a signal conditioning circuit, an A / D converter, a digital signal processing logic chip, a D / A converter, and a switching switch. The time-domain filter is used to receive the electrical signal output by the detector, filter out high-frequency interference and random noise, and improve the signal-to-noise ratio. The signal conditioning circuit is used to amplify, adjust the DC bias, impedance match, and adjust the amplitude of the time-domain filtered electrical signal. The A / D converter is used to convert the analog signal output by the signal conditioning circuit into a digital signal. The digital signal processing logic chip is used to demodulate, calculate the phase, correct the data, extract features, and perform calculations on the digital signal output by the A / D converter, and output the processing results. The D / A converter is used to convert the processed signal output by the digital signal processing logic chip into an analog signal. The switching switch is used to select the signal path and switch between multiple channels.

[0008] The multi-station data joint least squares method is solved by... Obtain the polar motion parameter vector ,in This is the weighting matrix, used to weight the Earth's angular velocity data from different fiber optic interferometer units. The matrix is ​​designed based on the geographical location of the fiber optic interferometer units. This is the difference vector between the observed value and the theoretical value of zero pole shift.

[0009] The weight matrix For a diagonal matrix, the diagonal elements The observation variance of the corresponding fiber optic interferometer unit at the observation station Inversely proportional.

[0010] The data transmission module transmits data via fiber optic link or satellite link. The data transmission module is equipped with a high-speed data channel, protocol converter and temporary buffer storage. The data processing center is equipped with functional modules for data reception, format conversion, filtering, outlier removal and visualization, and clock synchronization.

[0011] The error compensation module includes a temperature modeling compensation model and an installation error modeling compensation model. The error compensation module is pre-calibrated by measuring the output drift characteristics of the fiber optic interferometer under different temperature conditions to establish a corresponding temperature modeling compensation model. Through test calibration, a modeling compensation model for the installation error of the fiber optic interferometer is established. In actual operation, the error compensation module automatically adjusts the compensation parameters and correction coefficients based on the real-time collected environmental parameters and installation error information, and compensates for the Earth's angular velocity data output by the fiber optic interferometer unit.

[0012] After obtaining the Earth's polar motion variation curve, the data processing center compares and analyzes it with the standard polar motion data published by the International Earth Rotation Service to verify the system's measurement accuracy and reliability. It also conducts short-term and long-term statistical analyses of polar motion variations, evaluates the system's response capability to signals in different frequency bands, and optimizes the measurement algorithm.

[0013] A method for measuring the polar motion of the Earth based on a high-precision fiber optic interferometer, employing the aforementioned measurement system, specifically includes the following steps: (1) The Earth’s rotation angular velocity changes at different observation stations are monitored in real time by multiple fiber optic interferometer units to obtain Earth’s angular velocity data at each location; (2) The Earth's angular velocity data is transmitted to the data processing center via the data transmission module; (3) The data processing center preprocesses the collected Earth angular velocity data, constructs a system of linear equations, and solves the Earth polar motion variation curve by using the joint least squares method with multi-station data. (4) Use the error compensation module to compensate and correct the measurement results in real time to ensure the accuracy of the measurement curve.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The present invention sets up fiber optic interferometer units at multiple different locations to monitor the Earth's polar motion from multiple angles and in all directions. This layout effectively improves the accuracy and reliability of the measurement results and reduces the uncertainty and error impact of single-station measurements.

[0015] (2) The data processing center of this invention adopts the multi-station data joint least squares method, directly using the angular velocity data of each observation station to automatically identify and select the optimal combination of observation data. This process can suppress noise interference, enhance polar motion signal characteristics, and further improve the accuracy and resolution of Earth polar motion measurement.

[0016] (3) The error compensation module of the present invention can monitor the main error sources of the system in real time. Based on the real-time error situation, the module automatically adjusts the compensation parameters and dynamically compensates the measurement results based on the pre-established error model to ensure the stability of the measurement results. Attached Figure Description

[0017] Figure 1 This is a flowchart of the Earth polar motion measurement process of the present invention; Figure 2 This is a schematic diagram of the composition of the Earth polar motion measurement system based on a high-precision fiber optic interferometer according to the present invention; Figure 3 This is a schematic diagram of the fiber optic interferometer unit of the present invention; Figure 4 This is a flowchart of the method for measuring Earth's polar motion based on a high-precision fiber optic interferometer according to the present invention; Figure 5 This is a schematic diagram of the Earth's polar motion model of the present invention; Figure 6 This is a flowchart of the multi-station data joint least squares method solution of the present invention. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments: System Composition: This invention proposes a high-precision fiber optic interferometer-based Earth polar motion measurement system, comprising the following key components: multiple distributed fiber optic interferometer units, a data transmission module, a data processing center, and an error compensation module. Each fiber optic interferometer unit is deployed at observation stations at different geographical latitudes and longitudes, enabling real-time monitoring of angular velocity changes caused by the Earth's rotation and directly outputting angular velocity data for the corresponding acquisition location. The data transmission module is responsible for transmitting the angular velocity data measured by each unit to the data processing center. The data processing center uses a multi-station data joint least squares method to analyze and process the acquired angular velocity data, accurately reproducing the Earth's polar motion variation curve, thus achieving precise measurement of Earth's polar motion. The error compensation module monitors and compensates for potential measurement errors in the fiber optic interferometer units and the data processing center in real time, ensuring the accuracy of the measurement results.

[0019] Measurement Method: This invention utilizes the Sagnac interferometry principle to detect minute phase changes caused by the Earth's rotation using a fiber optic interferometer. A model of Earth's polar motion, incorporating annual and Chandler wobble components, is established. Based on the output signals from the fiber optic interferometers at each observation station, the variation curve of Earth's polar motion is derived using mathematical methods such as the least squares method. During the measurement process, an error compensation mechanism is introduced to compensate for and correct measurement errors caused by system noise and environmental interference in real time, thereby improving measurement accuracy.

[0020] System Setup To achieve high-precision measurement of Earth's polar motion, the first step is to lay out and install the system hardware. System setup mainly includes the following steps: Site selection and installation of observation stations: For example Figure 1As shown, multiple observation stations were selected at different geographical latitudes and longitudes to meet the requirements of Earth polar motion measurement. These stations should cover as many different regions of the globe as possible to provide comprehensive information on changes in Earth's angular velocity. Each observation station is equipped with a high-precision fiber optic interferometer unit (see [link to observation station]). Figure 2 The system includes a light source driving circuit (comprising a first light source driving circuit 1 and a second light source driving circuit 2), a self-stabilizing erbium-doped fiber light source 3, a spectral shaping module 4, and a nonlinear amplifier 5 to provide a highly stable broadband light source. A polarization suppressor 6, a fiber coupler 7, a high-performance Y-waveguide 8, and an ultra-long fiber ring 9 are used to polarize and modulate the interference light. A high-sensitivity detector 10, a time-domain filter 11, a signal conditioning circuit 12, an A / D converter 13, a digital signal processing logic chip 14, a D / A converter 15, and a switching switch 16 are responsible for processing the signals received by the detector, ultimately obtaining the angular velocity output 17. According to... Figure 2 The structure shown is used to assemble the fiber optic interferometer, and the equipment is installed and initially debugged according to the design requirements. During installation, key components such as the light source 3, fiber optic ring 9, and detector 10 should be correctly aligned and securely connected to ensure signal quality during measurement. During on-site installation, it is also necessary to adjust the light source power, monitor the detector voltage, adjust the parameters of the digital circuit to match the half-wave voltage of the Y-waveguide, and ensure the correct zero-point and noise characteristics of the fiber optic interferometer output. After installation, basic calibration is required to determine the zero bias and scale factor of the fiber optic interferometer, and to model and compensate for temperature and installation errors in the output data, ultimately ensuring that each unit can stably output accurate angular velocity data.

[0021] Data transmission and processing center deployment: The data transmission module transmits the angular velocity data collected by each site to the data processing center in real time via communication methods such as fiber optic links or satellite links (e.g., Figure 5 The data transmission process is illustrated. The data transmission module needs to be configured with a high-speed data channel, protocol converter, and temporary buffer storage to ensure efficient and reliable data delivery to the center. The data processing center is equipped with a high-performance computer cluster and large-capacity storage devices to execute algorithms such as multi-station joint least squares inversion (e.g.,...). Figure 6 (As shown). The data processing center deploys professional data processing software, including modules for data reception, format conversion, filtering, outlier removal, and visualization. It also features a user interface for real-time system monitoring. To ensure stable system operation, uninterruptible power supplies and redundant network connections are required, along with clock synchronization (e.g., using GPS synchronization technology) to ensure all observation data have a unified time reference. Furthermore, the center's database should archive and store historical measurement data for subsequent analysis and verification.

[0022] Error Compensation Module Deployment and Calibration: Error compensation modules are installed near the data processing center and various observation stations. Their function is to monitor system error sources in real time and perform modeling compensation. This module integrates environmental sensors (such as temperature and humidity sensors), installation error sensors, and incorporates a feedback control algorithm. The compensation module requires pre-calibration: for example, measuring the output drift characteristics of the fiber optic interferometer under different temperature conditions to establish a corresponding temperature modeling compensation model; simultaneously, through test calibration, establishing a modeling compensation model for the installation error of the fiber optic interferometer. In actual operation, the compensation module automatically adjusts the compensation parameters and correction coefficients based on real-time collected environmental parameters (such as temperature) and installation error information, and compensates for the output data of the fiber optic interferometer to reduce the impact of measurement errors caused by temperature fluctuations, inaccurate equipment installation, etc., on the results. Through the dynamic compensation of this module, the accuracy and stability of the final measurement results can be ensured to meet design requirements.

[0023] Measurement process After the system was set up, polar motion measurements were performed according to the predetermined procedure. The measurement process is as follows: Figure 3 As shown, the main steps include: Angular velocity detection and acquisition: High-precision fiber optic interferometer units at each observation station detect minute changes in angular velocity caused by the Earth's rotation based on the Sagnac interference principle (see...). Figure 2 Specifically, the light emitted by the light source is polarized by the Y-waveguide and split into two beams, which propagate clockwise and counterclockwise within the fiber optic ring, respectively. The output signal is then received by the detector after passing through a coupler and a beam splitter. Due to the Earth's rotation, the optical path length varies slightly in each direction, resulting in a measurable phase difference. This phase difference is then demodulated to obtain the local angular velocity value. Each interferometer unit acquires angular velocity data in real time and adds a precise timestamp, providing the foundational data for subsequent data processing. To improve measurement resolution, the fiber optic ring can be made of a high-refractive-index material, and a closed-loop temperature control device can be used to maintain a stable operating temperature and reduce environmental interference.

[0024] Data Acquisition and Transmission: During the measurement process, each fiber optic interferometer unit transmits the detected angular velocity data to the data processing center in real time via the data transmission module. For example... Figure 3 As shown, data transmission can utilize reliable methods such as wired fiber optic networks or satellite links to ensure high timeliness and data integrity. During transmission, the system can use time synchronization protocols (such as GPS synchronization) to timestamp the data, ensuring that data from all stations has a unified time reference. To ensure data security and integrity, data verification and encryption technologies can also be used to verify and encrypt the transmitted content. Upon arrival at the data processing center, the data first enters the data storage system, preparing it for subsequent processing.

[0025] Polar motion inversion calculation: At the data processing center, multi-station joint inversion is performed on the angular velocity data from various stations. First, a set of linear observation equations including polar motion parameters is established by combining the geographical location (latitude and longitude) of each observation station and the measured angular velocity.

[0026] Earth's instantaneous rotational angular velocity In the Earth-Fixed Coordinate System (CTS), it can be represented as:

[0027] in, It is the Earth's average angular rate of rotation; and It is a certain instant. The coordinate components of Earth's polar motion.

[0028] For the There are several observation stations, and their geographical locations are... ( Latitude (where longitude is 1), the sensitive axis direction vector of the fiber optic interferometer is 1. :

[0029] Then the first Theoretical angular velocity observations at each observation station for exist Projection on:

[0030] set up For the first Based on the angular velocity data measured at each observation station, an equation is established to determine the deviation between the observed and calculated values:

[0031] All At the same time, several observation stations By combining the collected data, we can construct the matrix form of the joint least squares method:

[0032] in For a moment The instantaneous polar shift parameter vector, For a moment The difference vector between the observed value and the theoretical value of zero pole shift, for The design matrix is ​​determined by the geographical location of each observation station.

[0033] The solution is obtained using a joint least squares method with multi-station data, and a weight matrix is ​​introduced. By weighting the accuracy of different observation stations, the optimal estimate of the polar motion parameter at that instant is obtained:

[0034] in, for Furthermore, to emphasize the independence of measurement errors among different observation stations, this invention adopts a diagonal weight matrix, the structure of which is as follows:

[0035] The diagonal elements of the weight matrix For the first The observation weights of each observation station are determined based on the observation accuracy of that station and the variance of the measurements taken by the fiber optic interferometer unit at that station. Inversely proportional:

[0036] in, Through the first Each fiber optic interferometer unit undergoes pre-experimental calibration or observation variance obtained through residual analysis during actual operation, thereby achieving optimized weighted processing of data with different observation qualities. This least-squares solution process is repeated continuously and at different time intervals, i.e., for... Solving for a series of time points will yield the results. By connecting the sequences, a continuous curve of Earth's polar motion over time can be accurately derived. Earth polar motion models typically include an annual component, a Chandler oscillation component, random noise, and long-term drift (see [link to relevant documentation]). Figure 4 Solving the equations using the least squares method yields a relatively definite time series curve of polar motion changes. For time series where a definite pattern is difficult to find, a compensation method is used for fitting. Specifically, the polar motion variable is treated as an unknown parameter, and a deviation equation between the observed and theoretical values ​​of angular velocity at each station is established. Then, the least squares iterative algorithm is used to solve this equation system. In actual calculations, reference can be made to... Figure 5 The data processing flowchart shown first obtains the measured angular velocity values ​​from the fiber optic interferometer and the theoretical angular velocity values ​​at different latitudes. Then, based on the polar motion observation model, a least-squares solution model is constructed, and data fitting and parameter estimation are completed step by step. An error compensation term is added to the solved model to make the final polar motion curve closer to the actual change. To improve the stability of the solution, the original data can also be filtered or subjected to Fourier analysis to suppress noise interference and extract significant polar motion signal components, thereby enhancing measurement accuracy and robustness.

[0037] Real-time error compensation: The error compensation module continuously monitors the environmental and device parameters of the entire measurement system and dynamically corrects the calculation results. For example, by acquiring information such as temperature and installation errors in real time, this module automatically adjusts the signal output or algorithm parameters according to a pre-established error compensation model. When a change in ambient temperature or instrument installation tilt angle is detected, the system can correct the corresponding measured values ​​through the compensation module, reducing the impact of errors on polar motion calculations. The final output polar motion curve is the result after error compensation correction, ensuring that the stability and accuracy of the measurement curve meet design requirements.

[0038] Results Verification and Analysis: After obtaining the polar motion variation curve, it can be compared and analyzed with standard polar motion data published by the International Earth Rotation and Reference Systems Service (IERS) to verify the system's measurement accuracy and reliability. Furthermore, short-term (daily scale) and long-term (monthly and yearly scale) statistical analyses of polar motion variations are performed to evaluate the system's response capability to signals in different frequency bands, and the measurement algorithm is optimized accordingly. For example, the spectral characteristics of the output curve can be analyzed to confirm whether the Chandler oscillation and annual periodic components are consistent with theory. Through comparative testing and error analysis, system performance is continuously optimized to achieve high-precision monitoring of Earth's polar motion.

[0039] The fiber optic interferometer unit also has self-diagnosis and fault alarm functions, which can promptly issue alarms and take corresponding measures when the equipment malfunctions, ensuring the normal operation of the system.

[0040] The data processing center also includes a database for storing and managing measurement data, and a user interface for visually displaying the measurement results.

[0041] The error compensation module can also compensate for long-term drift errors caused by environmental factors, such as polar shift changes caused by factors such as glacier melting and mantle flow.

[0042] The Earth polar motion model includes an annual component and a Chandler oscillation component, and the model parameters can be dynamically updated and optimized based on actual measurement data.

[0043] The fiber optic interferometer unit also has self-diagnosis and fault alarm functions, which can promptly issue alarms and take corresponding measures when the equipment malfunctions, ensuring the normal operation of the system.

[0044] The above description is only the best specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

[0045] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A system for measuring the polar motion of the Earth based on a high-precision fiber optic interferometer, characterized in that: It includes multiple fiber optic interferometer units, a data transmission module, a data processing center, and an error compensation module, among which, Multiple fiber optic interferometer units are set up at observation stations at different geographical latitudes and longitudes to monitor the changes in angular velocity caused by the Earth's rotation in real time and output the corresponding Earth angular velocity data. The data transmission module is used to transmit the Earth's angular velocity data collected by the fiber optic interferometer unit to the data processing center; The data processing center is used to receive and process Earth's angular velocity data, and to derive the Earth's polar motion variation curve by using a joint least squares method based on multi-station data. The error compensation module is used to compensate and correct measurement errors in the fiber optic interferometer unit and the data processing center in real time.

2. The Earth polar motion measurement system based on a high-precision fiber optic interferometer according to claim 1, characterized in that: It includes at least three fiber optic interferometer units.

3. The Earth polar motion measurement system based on a high-precision fiber optic interferometer according to claim 1, characterized in that: The fiber interferometer unit includes a light source driving circuit, a self-stabilized erbium-doped fiber light source (3), a spectrum shaping module (4), a nonlinear amplifier (5), a polarization suppressor (6), a fiber coupler (7), a Y-waveguide (8), a fiber ring (9), a detector (10), and a signal processing module. The light source driving circuit is used to provide power. The light emitted by the self-stabilized erbium-doped fiber light source (3) is split, combined, polarized, and phase-modulated by the Y-waveguide (8), and then generates a Sagnac phase difference through the fiber ring (9). The spectrum shaping module (4) is used to filter the spectrum and control the linewidth. The nonlinear amplifier (5) is used to amplify the optical signal. The polarization suppressor (6) is used to eliminate polarization-related noise and phase shift. The fiber coupler (7) is used to output the interference optical signal. The detector (10) is used to convert the interference signal into an electrical signal. The signal processing module is used to process and analyze the electrical signal.

4. The Earth polar motion measurement system based on a high-precision fiber optic interferometer according to claim 3, characterized in that: The signal processing module includes a time-domain filter (11), a signal conditioning circuit (12), an A / D converter (13), a digital signal processing logic chip (14), a D / A converter (15), and a switching switch (16). The time-domain filter (11) is used to receive the electrical signal output by the detector (10), filter out high-frequency interference and random noise, and improve the signal-to-noise ratio. The signal conditioning circuit (12) is used to amplify, DC bias adjust, impedance match and amplitude adjust the electrical signal after time domain filtering (11); the A / D converter (13) is used to convert the analog signal output by the signal conditioning circuit (12) into a digital signal; the digital signal processing logic chip (14) is used to demodulate, phase solve, data correct, feature extract and process the digital signal output by the A / D converter (13) and output the processing result; the D / A converter (15) is used to convert the processed signal output by the digital signal processing logic chip (14) into an analog signal; and the switching switch (16) is used to select the signal path and switch between multiple channels.

5. The Earth polar motion measurement system based on a high-precision fiber optic interferometer according to claim 1, characterized in that: The multi-station data joint least squares method is solved by... Obtain the polar motion parameter vector ,in This is the weighting matrix, used to weight the Earth's angular velocity data from different fiber optic interferometer units. The matrix is ​​designed based on the geographical location of the fiber optic interferometer units. This is the difference vector between the observed value and the theoretical value of zero pole shift.

6. The Earth polar motion measurement system based on a high-precision fiber optic interferometer according to claim 5, characterized in that: The weight matrix For a diagonal matrix, the diagonal elements The observation variance of the corresponding fiber optic interferometer unit at the observation station Inversely proportional.

7. The Earth polar motion measurement system based on a high-precision fiber optic interferometer according to claim 1, characterized in that: The data transmission module transmits data via fiber optic link or satellite link. The data transmission module is equipped with a high-speed data channel, protocol converter and temporary buffer storage. The data processing center is equipped with functional modules for data reception, format conversion, filtering, outlier removal and visualization, and clock synchronization.

8. The Earth polar motion measurement system based on a high-precision fiber optic interferometer according to claim 1, characterized in that: The error compensation module includes a temperature modeling compensation model and an installation error modeling compensation model. The error compensation module is pre-calibrated by measuring the output drift characteristics of the fiber optic interferometer under different temperature conditions to establish a corresponding temperature modeling compensation model. Through test calibration, a modeling compensation model for the installation error of the fiber optic interferometer is established. In actual operation, the error compensation module automatically adjusts the compensation parameters and correction coefficients based on the real-time collected environmental parameters and installation error information, and compensates for the Earth's angular velocity data output by the fiber optic interferometer unit.

9. The Earth polar motion measurement system based on a high-precision fiber optic interferometer according to claim 1, characterized in that: After obtaining the Earth's polar motion variation curve, the data processing center compares and analyzes it with the standard polar motion data published by the International Earth Rotation Service to verify the system's measurement accuracy and reliability. It also conducts short-term and long-term statistical analyses of polar motion variations, evaluates the system's response capability to signals in different frequency bands, and optimizes the measurement algorithm.

10. A method for measuring the polar motion of the Earth based on a high-precision fiber optic interferometer, characterized in that: The measurement system according to any one of claims 1 to 9 specifically includes the following steps: (1) The Earth’s rotation angular velocity changes at different observation stations are monitored in real time by multiple fiber optic interferometer units to obtain Earth’s angular velocity data at each location; (2) The Earth's angular velocity data is transmitted to the data processing center via the data transmission module; (3) The data processing center preprocesses the collected Earth angular velocity data, constructs a system of linear equations, and solves the Earth polar motion variation curve by using the joint least squares method with multi-station data. (4) Use the error compensation module to compensate and correct the measurement results in real time to ensure the accuracy of the measurement curve.

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