MEMS oscillator taming and holding system and method based on double-bridge structure

Abstract

The invention discloses a taming and holding system and method based on a double-bridge structure MEMS oscillator, and the system comprises a GNSS receiver and the double-bridge structure MEMS oscillator, the output ends of the GNSS receiver and the double-bridge structure MEMS oscillator are connected to a high-precision phase measurement module, the output end of the high-precision phase measurement module is connected to an MCU, the output end of the MCU is connected to a DAC conversion module, and the output end of the DAC conversion module is connected to a digital-to-analog converter. The output end of the DAC conversion module is connected to the double-bridge structure MEMS oscillator, the double-bridge structure MEMS oscillator outputs a signal to the high-precision phase measurement module through the phase-locked frequency division module, the MCU is connected with a temperature acquisition module, and the system further comprises a power supply module for supplying power to the system. Wherein the MCU comprises an EEPROM (Electrically Erasable Programmable Read-Only Memory) chip, and temperature compensation and aging time compensation model fitting data are stored in the EEPROM chip. And the frequency accuracy and the long-term frequency stability of the MEMS oscillator are effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of crystal oscillators, in particular to a taming and maintaining system and method of a MEMS oscillator based on a double-bridge structure. Background Art

[0002] Traditional crystal oscillators have problems such as insufficient accuracy, weak vibration resistance, and susceptibility to environmental interference in some scenarios with extremely high frequency requirements. At the same time, the trend of miniaturization of modern electronic devices is becoming more and more obvious. With the development of micro-electromechanical systems (MEMS) technology, MEMS oscillators have emerged. Compared with traditional oscillators, MEMS oscillators have some significant advantages, such as smaller size, can be integrated into small electronic devices, enhance the integration and portability of equipment, in addition, MEMS oscillators have low power consumption, can effectively reduce the energy consumption of the overall equipment, and also have the advantages of strong shock resistance and impact resistance. However, its frequency stability is still affected by many factors.

[0003] In a complex working environment, factors such as temperature changes, mechanical stress, and power supply voltage fluctuations can cause the frequency of the MEMS oscillator to drift. Especially for the dual-bridge MEMS oscillator, its unique dual-bridge structure brings some performance advantages, but also makes it more sensitive to environmental factors. For example, a slight change in temperature may cause thermal expansion or contraction of the dual-bridge material, causing uneven stress distribution inside the structure, and thus changing the resonant frequency of the oscillator.

[0004] Some existing oscillator taming methods are mainly designed for traditional quartz crystal oscillators, and have poor adaptability to MEMS oscillators; some can be used for general MEMS oscillators, but cannot effectively solve the frequency drift problem caused by the special structure of the dual-bridge structure MEMS oscillator. These methods have shortcomings in accuracy, complexity and cost, and cannot meet the needs of modern electronic systems for high-precision frequency output based on dual-bridge structure MEMS oscillators. Therefore, there is an urgent need for a taming method specifically for the unique dual-bridge structure MEMS oscillator to improve its frequency stability and ensure the reliable operation of the electronic system. Summary of the invention

[0005] The embodiment of the present invention provides a taming and maintaining system and method based on a dual-bridge structure MEMS oscillator, wherein the piezoelectric layer of the dual-bridge structure MEMS oscillator adopts a unique dual-bridge design and uses materials with high stability and low temperature coefficient, so that the frequency of the resonator changes very little under different temperature environments, greatly improving the stability of the natural frequency; based on this, an EEPROM chip storing temperature compensation and aging time compensation model fitting data is configured in its taming and maintaining system, and other measures are taken to effectively improve the frequency accuracy and long-term frequency stability of the MEMS oscillator.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] In a first aspect, an embodiment of the present invention provides a taming and maintaining system based on a dual-bridge structure MEMS oscillator, comprising: a GNSS receiver and a dual-bridge structure MEMS oscillator, wherein the output ends of the GNSS receiver and the dual-bridge structure MEMS oscillator are connected to a high-precision phase measurement module, the output end of the high-precision phase measurement module is connected to an MCU, the output end of the MCU is connected to a DAC conversion module, the output end of the DAC conversion module is connected to the dual-bridge structure MEMS oscillator through a signal conditioning circuit, the dual-bridge structure MEMS oscillator outputs a signal to the high-precision phase measurement module through a phase-locked frequency division module, the MCU is connected to a temperature acquisition module, and also includes a power supply module to power the system; wherein the MCU includes an EEPROM chip, and the EEPROM chip stores temperature compensation and aging time compensation model fitting data.

[0008] In some possible embodiments, the temperature compensation model fitting data is obtained by:

[0009] Establish a temperature compensation mathematical model, use a polynomial compensation algorithm to use a high-order polynomial to fit the frequency y-temperature x curve, and specifically use the fourth-order polynomial y=a0+a1x+a2x 2 +a3x 3 +a4x, where a0=0.4688, a1=-0.0733, a2=-0.0022, a3=0.00025, a4=-0.0000015. By measuring the frequency of the dual-bridge MEMS oscillator at different temperature points, a large number of experimental data points are obtained to fit a good fourth-order polynomial. At the same time, the fitted adjustment frequency y-temperature x data is stored in the EEPROM chip of the MCU.

[0010] In some possible embodiments, the aging time compensation model fitting data is obtained by:

[0011] Establish the mathematical model of aging time compensation, specifically adopt f(t)-f0=aln(t+t0)

[0012] f(t) is the frequency at time t, f0 is the initial frequency, and a is a constant related to the aging rate;

[0013] By measuring the frequency of the dual-bridge MEMS oscillator at different time points, a large number of test data points are obtained to fit the aging time compensation mathematical formula. At the same time, the fitted adjustment frequency (f(t)-f0)-time t data is stored in the EEPROM chip of the MCU.

[0014] In some possible embodiments, the dual-bridge structure MEMS oscillator includes a dual-bridge structure MEMS resonator, a piezoelectric layer is arranged in the dual-bridge structure MEMS resonator, the piezoelectric layer is a symmetrical structure with the center line of the square central anchor as the longitudinal symmetry axis, the two sides of the central anchor are respectively connected in sequence to the first connecting beam and the first circular ring, and the second connecting beam and the second circular ring, the first connecting beam, the second connecting beam, the center of the first circular ring and the center of the second circular ring are on the same straight line, the same straight line is also the transverse symmetry axis of the piezoelectric layer, the longitudinal symmetry axis and the transverse symmetry axis are perpendicular to each other. The height of the piezoelectric layer structure is relatively uniform, showing a rectangular shape, the height of the structure is related to the vibration characteristics of the dual-ring structure, and the uniform height helps to ensure the stability of the structure during vibration.

[0015] In some possible embodiments, the inner radius and the outer radius of the first circular ring and the second circular ring are determined by a preset frequency threshold f0, and the preset frequency threshold is approximately:

[0016]

[0017] Wherein R1 and R2 represent the inner radius and outer radius of the first circular ring and the second circular ring, E is the Young's modulus of the material used, and ρ is the density of the material used.

[0018] In some possible embodiments, the lengths of the first connecting beam and the second connecting beam are determined by a quarter-wavelength coupling method, the breathing mode frequencies f0 of the first circular ring and the second circular ring are matched with the extension mode frequencies of the first connecting beam and the second connecting beam, and the lengths L of the first connecting beam and the second connecting beam are calculated by the formula:

[0019]

[0020] Wherein, Vl represents the speed of sound waves in the direction of the piezoelectric layer.

[0021] In some possible embodiments, the piezoelectric layer uses single crystal silicon, and the electrode portion uses gold as the electrode material.

[0022] In some possible embodiments, a phase-locked frequency division module is further included, wherein an input end of the phase-locked frequency division module is connected to an output end of the GNSS receiver, and an output end of the phase-locked frequency division module is connected to the high-precision phase measurement module.

[0023] In some possible embodiments, the MCU further includes taming and maintaining frequency control software for controlling the dual-bridge structure MEMS oscillator to tame and maintain a preset frequency threshold.

[0024] In a second aspect, an embodiment of the present invention provides a method for taming and maintaining a MEMS oscillator based on a dual-bridge structure, the method comprising the following steps:

[0025] The system is powered on and a frequency threshold is preset when the system starts. The MCU reads a preset initial reference first adjustment frequency and configuration parameters from the EEPROM chip according to the initial frequency value of the dual-bridge structure MEMS oscillator. The configuration parameters include the setting of internal registers, port initialization, clock configuration, etc.

[0026] The MCU inputs the read preset initial reference first adjustment frequency into the DAC conversion module, and adjusts the frequency of the dual-bridge structure MEMS oscillator through the DAC to convert the initial frequency into the second frequency;

[0027] The second frequency is input into the high-precision phase measurement module after being processed by the phase-locked frequency division processing module; the GNSS receiver receives the standard frequency, and after being processed by the phase-locked frequency multiplication module, it is also input into the high-precision phase measurement module; the high-precision phase measurement module compares the second frequency with the standard frequency to obtain phase difference data;

[0028] The temperature acquisition module starts to collect ambient temperature data and transmits the ambient temperature data to the MCU;

[0029] The MCU receives the phase difference data for calculating the adjustment frequency data; at the same time, the MCU reads the corresponding temperature compensation data from the EEPROM chip according to the ambient temperature data, and reads the corresponding aging compensation data from the EEPROM chip according to the aging time data; the MCU obtains the second adjustment frequency data through calculation, and adjusts the frequency of the dual-bridge structure MEMS oscillator through the DAC to change the second frequency into the third frequency;

[0030] Repeat the processing of the second frequency for the third frequency, and repeat N times until the Nth frequency is adjusted to meet the preset frequency threshold;

[0031] During system operation, the MCU continuously monitors the data and temperature data of the high-precision phase measurement module and adjusts the frequency of the MEMS oscillator in real time;

[0032] EEPROM regularly updates and stores data such as temperature and aging to ensure the stability of the system in long-term operation.

[0033] The advantages of the present invention are:

[0034] The present invention provides a dual-bridge structure MEMS oscillator taming and holding system and method, and a dual-bridge structure MEMS oscillator taming and holding system, wherein the piezoelectric layer of the dual-bridge structure MEMS oscillator adopts a unique dual-bridge design, a symmetrical structure with the center line of a square central anchor as the longitudinal symmetry axis, two symmetrical independent rings are connected on both sides of the central anchor by two bridges, and the two independent rings and the strip structure are excited in an extended vibration mode, and the mode shows complete symmetry with respect to the central anchor point, thereby effectively suppressing the anchor point loss transmitted to the substrate; in addition, the extended vibration mode presented in the ring and strip structure has an extremely low strain gradient Characteristics, this characteristic significantly reduces the energy loss caused by the thermoelastic dissipation effect; moreover, the piezoelectric layer uses single crystal silicon, and the electrode part uses gold as the electrode material. The material has a low temperature coefficient, which makes the frequency of the resonator change very little under different temperature environments. These factors combined greatly improve the stability of the natural frequency, that is, provide a stable frequency reference for high-precision crystal oscillators; based on this, an EEPROM chip storing the fitting data of the temperature compensation and aging time compensation models is configured in its taming and maintenance system, which greatly improves the calculation speed of the MCU. Specifically, the fourth-order polynomial y=a0+a1x+a2x is used. 2 +a3x 3 +a4x compensation algorithm is used to fit and adjust the frequency y-temperature x curve. By measuring the frequency of the dual-bridge structure MEMS oscillator at different temperature points, a large number of test data points are obtained to fit a well-fitted fourth-order polynomial, which effectively improves the frequency accuracy and long-term frequency stability of the MEMS oscillator. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of a taming and holding system based on a double-bridge structure MEMS oscillator according to an embodiment of the present invention;

[0036] Figure 2a 2b and 2c are the front view, top view, and left (right) view of the piezoelectric layer of the taming and holding system based on the double-bridge structure MEMS oscillator according to an embodiment of the present invention;

[0037] Figure 3 It is a flow chart of a taming and maintaining method based on a double-bridge structure MEMS oscillator according to an embodiment of the present invention;

[0038] Figure 4 This is an oscillation circuit diagram of a MEMS oscillator based on a double-bridge structure according to an embodiment of the present invention.

[0039] In the figure, 1-central anchor, 21-first circular ring, 22-second circular ring, 31-first connecting beam, 32-second connecting beam, 4-height of piezoelectric layer structure, 100-temperature control circuit, 200-frequency signal generating circuit (where G1 is a double-bridge structure MEMS resonator), 300-oscillation circuit of the frequency signal generating circuit, 400-two-stage discharge circuit of the frequency signal generating circuit. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. At the same time, in the description of the embodiments of the present application, the terms "first", "second", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0041] Embodiment 1

[0042] The embodiment of the present invention provides a MEMS oscillator taming and holding system based on a double-bridge structure, see Figure 1 ,include:

[0043] GNSS receiver and dual-bridge structure MEMS oscillator, the output end of the GNSS receiver and the dual-bridge structure MEMS oscillator are connected to a high-precision phase measurement module, the output end of the high-precision phase measurement module is connected to an MCU, the output end of the MCU is connected to a DAC conversion module, the output end of the DAC conversion module is connected to the dual-bridge structure MEMS oscillator through a signal conditioning circuit, the dual-bridge structure MEMS oscillator outputs a signal to the high-precision phase measurement module through a phase-locked frequency division module, the MCU is connected to a temperature acquisition module, and also includes a power supply module to power the system; wherein the MCU includes an EEPROM chip, and the EEPROM chip stores temperature compensation and aging time compensation model fitting data. In this embodiment, it also includes a phase-locked frequency division module, the input end of the phase-locked frequency division module is connected to the output end of the GNSS receiver, and the output end is connected to the high-precision phase measurement module. In this embodiment, the MCU also includes taming and maintaining frequency control software, which is burned into the flash chip of the MCU, and is used to control the taming and maintenance of the preset frequency threshold based on the dual-bridge structure MEMS oscillator.

[0044] The dual-bridge structure MEMS oscillator of the present embodiment includes a dual-bridge structure MEMS resonator and an oscillation circuit. A piezoelectric layer is arranged in the dual-bridge structure MEMS resonator, and the piezoelectric layer is a symmetrical structure with the center line of the square central anchor as the longitudinal symmetry axis. The central anchor in the present embodiment is rectangular, and the center line in the length direction is the longitudinal symmetry axis. The first connecting beam and the first circular ring, as well as the second connecting beam and the second circular ring are sequentially connected on both sides of the central anchor. The center of the first connecting beam, the second connecting beam, the first circular ring and the center of the second circular ring are on the same straight line, which is also the transverse symmetry axis of the piezoelectric layer, and the longitudinal symmetry axis and the transverse symmetry axis are perpendicular to each other; the first circular ring and the second circular ring have exactly the same structure; the first connecting beam and the second connecting beam are also exactly the same rectangular strip structure, and the center line in the length direction coincides with the transverse symmetry axis. The height of the piezoelectric layer structure is relatively uniform, showing a rectangular shape. The height of the structure is related to the vibration characteristics of the dual-ring structure. The uniform height helps to ensure the stability of the structure during vibration. The two independent circular rings and the strip structure are excited in the extended vibration mode. The mode shows complete symmetry relative to the central anchor (point), thereby effectively suppressing the anchor loss transmitted to the substrate. In addition, the extended vibration mode presented in the circular ring and the strip structure has an extremely low strain gradient characteristic, which significantly reduces the energy loss caused by the thermoelastic dissipation effect and plays an extremely important role in improving the stability of its natural frequency. In short, the symmetry of the dual-ring structure has an important influence on its performance. Ensuring the symmetry of the dual rings in shape, size and material can reduce the complexity of the vibration mode and frequency splitting caused by asymmetry. By optimizing the design, the dual rings can be made as symmetrical as possible, which can improve the singleness and stability of the frequency, which is conducive to the MEMS oscillator outputting a pure frequency signal. In this embodiment, the inner radius and outer radius of the first circular ring and the second circular ring are determined by a preset frequency threshold f0, and the preset frequency threshold is approximately:

[0045]

[0046] Wherein R1 and R2 represent the inner radius and outer radius of the first circular ring and the second circular ring, E is the Young's modulus of the material used, and ρ is the density of the material used;

[0047] In this embodiment, the lengths of the first connecting beam and the second connecting beam are determined by a quarter-wavelength coupling method, and the breathing mode frequencies f0 of the first circular ring and the second circular ring are matched with the extension mode frequencies of the first connecting beam and the second connecting beam. The lengths L of the first connecting beam and the second connecting beam are calculated by the formula:

[0048]

[0049] Among them, V l represents the speed of sound waves in the direction of the piezoelectric layer.

[0050] In this embodiment, the piezoelectric layer uses single crystal silicon, and the electrode part uses gold as the electrode material. The material has a low temperature coefficient, so that the frequency of the resonator changes very little under different temperature environments.

[0051] Oscillator circuits, such as Figure 3 As shown, the circuit uses a low-noise amplifier, which can effectively amplify the signal while minimizing the introduction of additional noise to ensure signal purity, further improving the quality of the output frequency signal of the dual-bridge structure MEMS oscillator, and providing a high-quality input frequency signal for the frequency comparison and control adjustment of the subsequent high-precision phase measurement module.

[0052] The oscillation circuit is divided into temperature control circuit ( Figure 4 100) and the frequency signal generating circuit ( Figure 4 200) in two parts.

[0053] The temperature control circuit controls the circuit temperature through the power transistor V2. It controls the collector current by adjusting the base current, thereby controlling the temperature of the heat sink chip. The base current is determined by the voltage division of thermistor R10. At the same time, the current from the base is enhanced through the two-stage discharge circuit (amplifiers N2 and N3), thereby enhancing the sensitivity of the power transistor to the circuit.

[0054] The signal generating circuit consists of an oscillating circuit ( Figure 4 The oscillator circuit is a three-point capacitor oscillator circuit. L4 is connected in series with C23 and in parallel with L6 to suppress the resonance of the crystal oscillator at other frequencies. At the same time, the two-stage discharge circuit ( Figure 4 400) in the figure amplifies the signal generated by the crystal oscillator, N5 is an inverter, and the signal generates a square wave signal through the inverter.

[0055] In this embodiment, a temperature compensation model is used to fit data, and a method for obtaining the fitting data includes:

[0056] Establish a temperature compensation mathematical model, use a polynomial compensation algorithm to use a high-order polynomial to fit the frequency y-temperature x curve, and specifically use the fourth-order polynomial y=a0+a1x+a2x 2 +a3x 3+a4x, where a0=0.4688, a1=-0.0733, a2=-0.0022, a3=0.00025, a4=-0.0000015. By measuring the frequency of the dual-bridge structure MEMS oscillator at different temperature points, a large number of test data points are obtained to fit a good fourth-order polynomial with high data accuracy. At the same time, the fitted adjustment frequency y-temperature x data is stored in the EEPROM chip of the MCU, and the MCU can use it at any time during calculation. The temperature acquisition module has multiple high-sensitivity temperature sensors, which are distributed around the MEMS resonator and key circuit parts. Thermistors are used for temperature acquisition. Thermistors have leads and can be flexibly placed in any position. The MCU receives ambient temperature data, accurately predicts the impact of temperature on frequency, and adjusts the output frequency in time to ensure that the crystal oscillator maintains high precision in a wide temperature range, greatly improving the control efficiency of MCU taming and maintaining frequency stability.

[0057] The aging time compensation model fitting data is obtained by:

[0058] Establish a mathematical model for aging time compensation, specifically using f(t)-f0=aln(t+t0), where f(t) is the frequency at the moment, f0 is the initial frequency, and a is a constant related to the aging rate;

[0059] By measuring the frequency of the dual-bridge MEMS oscillator at different time points, a large number of test data points are obtained to fit the fitted mathematical formula for aging time compensation. At the same time, the fitted adjustment frequency (f(t)-f0)-time t data is stored in the EEPROM chip of the MCU and can be used at any time during MCU calculation, which greatly improves the control efficiency of MCU taming and maintaining frequency stability.

[0060] According to the technical solution of this embodiment, the inventor has specifically designed a dual-bridge structure MEMS oscillator, in which the specific parameters of the dual-bridge structure MEMS resonator and the piezoelectric layer set therein are introduced here. The operating frequency of the dual-bridge structure MEMS resonator is about 10.6MHz, and the piezoelectric layer of the resonator consists of two symmetrical rings, which are connected by two identical beams centrally anchored at the central node. The MEMS structure presents two interconnected annular structures (a first circular ring and a second circular ring) in the top view. Each annular structure is a circular ring with an inner diameter of 115μm and an outer diameter of 125μm. The two annular structures are connected together by a rectangular connecting beam (a first connecting beam and a second connecting beam), and the length of the connecting beam is about 200μm and the width is 12μm. The two annular structures are symmetrically distributed in the longitudinal direction, and the connecting beam is located on the horizontal axis to connect the two rings together. The entire structure is also symmetrical in the horizontal direction. The main view Figure 2 (a) shows the thickness distribution of the dual-ring structure. The dual-ring structure extends in the horizontal direction and is about 620μm long. The front view of Figure 2(c) shows the height distribution of the dual-ring structure. The dual-ring structure extends in the horizontal direction, with a length of about 620μm and a height of about 20μm. The height of the structure is relatively uniform, showing a rectangular shape. The height of the structure is related to the vibration characteristics of the dual-ring structure, and the uniform height helps to ensure the stability of the structure during vibration; the size of the dual ring: the size of the ring in the dual-ring structure is a key parameter. Optimizing the diameter, width and other dimensions of the ring can affect the frequency characteristics of MEMS; connection structure: There is a connection structure between the dual rings in the figure, and the design of this connection structure needs to be optimized. Optimizing the shape, size and position of the connection structure can improve the coupling strength between the dual rings. A reasonable connection structure can ensure efficient and stable energy transfer between the two loops, which helps to improve the frequency stability and the overall performance of the oscillator; symmetry: The symmetry of the dual-ring structure has an important influence on its performance. Ensuring the symmetry of the dual rings in shape, size and material can reduce the complexity of the vibration mode and frequency splitting caused by asymmetry. By optimizing the design to make the dual rings as symmetrical as possible, the singleness and stability of the frequency can be improved, which is conducive to the MEMS oscillator outputting a pure frequency signal.

[0061] Embodiment 2

[0062] The embodiment of the present invention provides a method for taming and maintaining a MEMS oscillator based on a dual-bridge structure, comprising the following steps:

[0063] Power on and start the system. When the system starts, the MCU reads a preset initial reference first adjustment frequency and configuration parameters from the EEPROM chip according to the initial frequency value of the dual-bridge structure MEMS oscillator;

[0064] The MCU inputs the read preset initial reference first adjustment frequency into the DAC conversion module, and adjusts the frequency of the dual-bridge structure MEMS oscillator through the DAC to convert the initial frequency into the second frequency;

[0065] The second frequency is input into the high-precision phase measurement module after being processed by the phase-locked frequency division processing module; the GNSS receiver receives the standard frequency, and after being processed by the phase-locked frequency multiplication module, it is also input into the high-precision phase measurement module; the high-precision phase measurement module compares the second frequency with the standard frequency to obtain phase difference data;

[0066] The temperature acquisition module starts to collect ambient temperature data and transmits the ambient temperature data to the MCU;

[0067] The MCU receives the phase difference data for calculating the adjustment frequency data; at the same time, the MCU reads the corresponding temperature compensation data from the EEPROM chip according to the ambient temperature data, and reads the corresponding aging compensation data from the EEPROM chip according to the aging time data; the MCU obtains the second adjustment frequency data through calculation, and adjusts the frequency of the dual-bridge structure MEMS oscillator through the DAC to change the second frequency into the third frequency;

[0068] Repeat the processing of the second frequency for the third frequency, and repeat N times until the Nth frequency is adjusted to meet the preset frequency threshold;

[0069] During system operation, the MCU continuously monitors the data and temperature data of the high-precision phase measurement module and adjusts the frequency of the MEMS oscillator in real time;

[0070] The EEPROM periodically updates and stores temperature compensation data and aging data.

Claims

1. A MEMS oscillator taming and holding system based on a dual-bridge structure, characterized in that: include: A GNSS receiver and a dual-bridge structure MEMS oscillator, wherein the output ends of the GNSS receiver and the dual-bridge structure MEMS oscillator are connected to a high-precision phase measurement module, the output end of the high-precision phase measurement module is connected to an MCU, the output end of the MCU is connected to a DAC conversion module, the output end of the DAC conversion module is connected to a dual-bridge structure MEMS oscillator, the dual-bridge structure MEMS oscillator outputs a signal to the high-precision phase measurement module through a phase-locked frequency division module, the MCU is connected to a temperature acquisition module, and also includes a power supply module to power the system; wherein the MCU includes an EEPROM chip, and the EEPROM chip stores temperature compensation and aging time compensation model fitting data.

2. The dual-bridge structure MEMS oscillator taming and holding system according to claim 1 is characterized in that: The method for obtaining the temperature compensation model fitting data includes: Establish a temperature compensation mathematical model, use a polynomial compensation algorithm to use a high-order polynomial to fit the frequency y-temperature x curve, and specifically use the fourth-order polynomial y=a0+a1x+a2x 2 +a3x 3 +a4x, where a0=0.4688, a1=-0.0733, a2=-0.0022, a3=0.00025, a4=-0.0000015. By measuring the frequency of the dual-bridge MEMS oscillator at different temperature points, a large number of experimental data points are obtained to fit a good fourth-order polynomial. At the same time, the fitted adjustment frequency y-temperature x data is stored in the EEPROM chip of the MCU.

3. The dual-bridge structure MEMS oscillator taming and holding system according to claim 1 or 2, characterized in that: The aging time compensation model fitting data is obtained by: Establish a mathematical model for aging time compensation, specifically using f(t)-f0=aln(t+t0), where f(t) is the frequency at the moment, f0 is the initial frequency, and a is a constant related to the aging rate; By measuring the frequency of the dual-bridge MEMS oscillator at different time points, a large number of test data points are obtained to fit the aging time compensation mathematical formula. At the same time, the fitted adjustment frequency (f(t)-f0)-time t data is stored in the EEPROM chip of the MCU.

4. The dual-bridge structure MEMS oscillator taming and holding system according to claim 3 is characterized in that: The double-bridge structure MEMS oscillator includes a double-bridge structure MEMS resonator, in which a piezoelectric layer is arranged, and the piezoelectric layer is a symmetrical structure with the center line of the square central anchor as the longitudinal symmetry axis, and the first connecting beam and the first circular ring, as well as the second connecting beam and the second circular ring are connected in sequence on both sides of the central anchor, and the centers of the first connecting beam, the second connecting beam, the first circular ring and the second circular ring are on the same straight line, and the same straight line is also the transverse symmetry axis of the piezoelectric layer, and the longitudinal symmetry axis and the transverse symmetry axis are perpendicular to each other.

5. The dual-bridge structure MEMS oscillator taming and holding system according to claim 4 is characterized in that: The inner radius and outer radius of the first circular ring and the second circular ring are determined by a preset frequency threshold f0, which is approximately: Wherein R1 and R2 represent the inner radius and outer radius of the first circular ring and the second circular ring, E is the Young's modulus of the material used, and ρ is the density of the material used.

6. The dual-bridge structure MEMS oscillator taming and holding system according to claim 5 is characterized in that: The lengths of the first connecting beam and the second connecting beam are determined by a quarter-wavelength coupling method, and the breathing mode frequencies f0 of the first circular ring and the second circular ring are matched with the extension mode frequencies of the first connecting beam and the second connecting beam, and the lengths L of the first connecting beam and the second connecting beam are calculated by the formula: Among them, V l represents the speed of sound waves in the direction of the piezoelectric layer.

7. The dual-bridge structure MEMS oscillator taming and holding system according to any one of claims 4 to 6, characterized in that: The piezoelectric layer uses single crystal silicon, and the electrode portion uses gold as electrode materials.

8. The dual-bridge structure MEMS oscillator taming and holding system according to claim 7 is characterized in that: It also includes a phase-locked frequency division module, the input end of the phase-locked frequency division module is connected to the output end of the GNSS receiver, and the output end is connected to the high-precision phase measurement module.

9. The dual-bridge structure MEMS oscillator taming and holding system according to any one of claim 8, characterized in that: The MCU also includes taming and maintaining frequency control software, which is used to control the dual-bridge structure MEMS oscillator to tame and maintain a preset frequency threshold.

10. A method for taming and maintaining a MEMS oscillator based on a dual-bridge structure, characterized in that: Based on the dual-bridge structure MEMS oscillator taming and holding system according to claim 9, the method comprises the following steps: Power on and start the system. When the system starts, the MCU reads a preset initial reference first adjustment frequency and configuration parameters from the EEPROM chip according to the initial frequency value of the dual-bridge structure MEMS oscillator; The MCU inputs the read preset initial reference first adjustment frequency into the DAC conversion module, and adjusts the frequency of the dual-bridge structure MEMS oscillator through the DAC to convert the initial frequency into the second frequency; The second frequency is processed by phase-locked frequency division and then input into the high-precision phase measurement module; The GNSS receiver receives the standard frequency, which is then processed by the phase-locked frequency multiplication module and then input into the high-precision phase measurement module. The high-precision phase measurement module compares the second frequency with the standard frequency to obtain phase difference data; The temperature acquisition module starts to collect ambient temperature data and transmits the ambient temperature data to the MCU; The MCU receives the phase difference data for calculating the adjustment frequency data; at the same time, the MCU reads the corresponding temperature compensation data from the EEPROM chip according to the ambient temperature data, and reads the corresponding aging compensation data from the EEPROM chip according to the aging time data; the MCU obtains the second adjustment frequency data through calculation, and adjusts the frequency of the dual-bridge structure MEMS oscillator through the DAC to change the second frequency into the third frequency; Repeat the processing of the second frequency for the third frequency, and repeat N times until the Nth frequency is adjusted to meet the preset frequency threshold; During system operation, the MCU continuously monitors the data and temperature data of the high-precision phase measurement module and adjusts the frequency of the MEMS oscillator in real time; The EEPROM periodically updates and stores temperature compensation data and aging data.

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