Miniaturized MEMS gravimeter and orthogonalization regression-based gravity measurement environment compensation method thereof

Abstract

The invention belongs to the technical field of instruments and meters, and discloses a miniaturized MEMS gravimeter and a gravity measurement environment compensation method based on orthogonalization regression. The miniaturized MEMS gravimeter provided by the invention adopts a compact structural design and has the characteristic of low power consumption. According to the method, a tidal component protecting group is constructed, strict orthogonalization processing is carried out on environmental variables, effective separation of tidal components and environmental disturbance in a mathematical space is achieved, and the problem that tidal signals are wrongly absorbed or weakened due to frequency spectrum overlapping in a traditional compensation method is solved. The characteristic ensures that the amplitude and the phase of the earth tide signal are kept in physical consistency, so that the gravity measurement result is more reliable and accurate, and the method is particularly suitable for long-term continuous observation tasks sensitive to tide characteristics.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of instruments and meters, and more particularly relates to a miniaturized MEMS gravimeter and a gravity measurement environment compensation method based on orthogonalization regression. BACKGROUND

[0002] As a key instrument in the fields of geological exploration, earthquake monitoring, mineral resource exploration, and underground water and oil detection, gravimeters are widely used in scientific research and engineering practice. Traditional gravimeters, such as cold atom gravimeters, superconducting gravimeters, and quartz spring gravimeters, have high precision and good stability, but they are bulky and usually require complex environmental isolation systems, and are high in cost, which limits their use in some special applications. For example, in underground exploration, deep well monitoring, and mobile device applications, the volume and weight of traditional gravimeters cannot meet the requirements.

[0003] In recent years, MEMS gravity sensors have gradually become a key technology in the fields of geophysical exploration and engineering measurement due to their small size, low power consumption, and ease of batch manufacturing. MEMS gravimeters can achieve portability while maintaining high sensitivity, greatly improving the efficiency of mineral resource exploration, oil and gas exploration, and earthquake monitoring, and are particularly suitable for low-cost, large-scale real-time monitoring networks. The small size and low power consumption of MEMS gravimeters make them have application potential in unmanned aerial vehicles, ocean probes, and space exploration missions. Therefore, MEMS gravimeters have become a key technology for promoting the development of gravity measurement towards miniaturization, low cost, and wide area.

[0004] However, despite the great potential of MEMS gravimeters in miniaturization and low cost, their application still faces some significant problems, especially in terms of miniaturization. Although the volume of MEMS gravity chips is much smaller than that of traditional gravimeters, the overall size of current MEMS gravimeters is still too large, failing to fully exploit the advantages of MEMS technology. This problem is particularly prominent in situations that require extreme miniaturization, such as deep well exploration, unmanned aerial vehicle mounting, portable devices, and arrayed gravity measurement, limiting the optimal application of MEMS gravimeters in these fields.

[0005] In addition, MEMS gravimeters are greatly affected by environmental factors, especially the interference of air pressure, temperature and tilt effect on the sensor output seriously affects its long-term stability and high-precision application. Specifically, air pressure changes cause changes in air density, affecting the buoyancy of the sensitive structure, producing an air pressure coefficient of about 5 μGal / Pa, resulting in mGal-level gravity fluctuations every day; temperature changes change the Young's modulus and thermal expansion coefficient of the sensitive structure material, change the stiffness and natural frequency of the beam, and its temperature coefficient is 64 μGal / mK, which requires precise temperature control; the tilt effect will make the gravity value measurement decrease, thereby affecting the precision.

[0006] Although the environmental suppression capability of small MEMS gravimeters is improved by sealing the tube shell, enhancing the temperature control structure, and adding a tilt monitoring unit, the existing hardware suppression technology still cannot completely isolate external disturbances, and its effect is particularly limited in the low frequency band. In order to further reduce the influence of the environment on gravity measurement, the existing environmental compensation method mainly relies on least squares linear regression, correlation analysis or multivariate linear modeling, and realizes compensation by regression fitting of environmental variables such as air pressure, temperature and tilt. However, due to the significant spectral overlap between environmental variables and real gravity signals such as solid tides in the low frequency band, such traditional methods have the following outstanding defects: (1) Tidal signal interference problem: solid tides are real signals in gravity measurement, and their main frequencies (such as 8, 12, 24 hours, etc.) are highly overlapped with the low-frequency drift of environmental variables such as air pressure and temperature. In the traditional linear regression model lacking of constraints, part of the tidal components will be wrongly attributed to environmental disturbances, resulting in phenomena such as amplitude weakening, phase shift and even period component leakage of main tidal frequencies, affecting the physical consistency of observation data.

[0007] (2) Multiple collinearity leads to unstable regression coefficients: there is significant correlation and coupling between environmental variables such as air pressure, temperature, tilt and structural response caused by material thermal stress, forming a typical multiple collinearity problem. In this case, the traditional least squares regression is highly sensitive to the correlation structure between variables, leading to unstable regression coefficients, significant changes in amplitude over time, and even sign reversal, and may produce overfitting. The compensation model constructed in this way is difficult to maintain consistency and repeatability across time periods, resulting in a lack of robustness of the compensation effect.

[0008] (3) Ignoring the time delay effect of environmental response: the influence of environmental factors on the gravimeter is not an instant response. For example, thermal conduction has a physical delay, the deformation of the shell caused by air pressure loading has a slow response process, and the change in inclination may also be in the form of hysteresis in the structure. If the compensation model does not consider these time delay effects, the true correspondence between the environmental variables and the gravity response will be deviated, resulting in increased fitting error, decreased compensation effect, and difficulty in achieving high-precision long-term gravity measurement.

[0009] In summary, the traditional environmental compensation method is difficult to simultaneously solve the key problems of tidal component protection, multiple collinearity inhibition and environmental time delay modeling, which limits the application of miniaturized gravimeters in long-term stable observation. Therefore, there is an urgent need for a more robust, physically meaningful and universally applicable environmental compensation method. SUMMARY

[0010] In view of the above defects or improvement needs of the prior art, the present application provides a miniaturized MEMS gravimeter and a gravity measurement environmental compensation method based on orthogonal regression, which aims to solve the technical problem that the traditional environmental compensation method is difficult to simultaneously solve the problems of tidal component protection, multiple collinearity inhibition and environmental time delay modeling.

[0011] To achieve the above-mentioned purpose, the present application provides a miniaturized MEMS gravimeter, which comprises a gravity sensing chip, a tube shell, a multi-stage temperature control system, a processor, an electromagnetic shielding shell, an inclinometer, a leveling foot, and a barometer. The gravity sensing chip and the barometer are packaged together inside the tube shell. The barometer is used to detect the air pressure information in the tube shell. The multi-stage temperature control system is arranged outside the tube shell and is used to actively control the temperature of the gravity sensing chip. The electromagnetic shielding shell is arranged at the outermost side and is used to suppress external electromagnetic interference. The leveling foot is arranged at the bottom and is used to level the MEMS gravimeter. The inclinometer is arranged below the gravity sensing chip and is mounted on the same mechanical reference structure as the gravity sensing chip, so that the attitude change measured by the inclinometer is consistent with the attitude change of the gravity sensing chip, and the inclinometer is used to detect the attitude inclination information of the MEMS gravimeter. The processor is electrically connected with the gravity sensing chip, the multi-stage temperature control system, the inclinometer and the barometer, and is used to receive the temperature signal obtained by the multi-stage temperature control system, the air pressure signal obtained by the barometer and the attitude inclination signal obtained by the inclinometer, and to perform error compensation processing on the gravity measurement signal output by the gravity sensing chip according to the above environmental information.

[0012] Preferably, the material of the tube shell is ceramic or Kovar alloy, and the tube shell is a sealed packaging structure, which can be a vacuum packaging or normal pressure packaging.

[0013] Preferably, the multi-stage temperature control system is provided with at least two layers of temperature control structures, each layer of temperature control structure is provided with a heating film and a temperature detection device, and a heat insulation layer is arranged between adjacent temperature control structures to reduce the heat coupling between layers and inhibit the transmission of external temperature disturbance, and the temperature control precision is improved step by step from outside to inside, so as to realize the miniaturization of the system while ensuring the temperature control performance. The application also provides a gravity measurement environment compensation method based on orthogonal regression, which comprises the following steps: Step 1, collecting original gravity measurement data and environment variable data of the miniaturized MEMS gravity meter, wherein the environment variable data comprises air pressure data, temperature data and inclination data; Step 2, constructing a tide protection base for representing the main variation characteristics of the solid tide in the original gravity measurement data; Step 3, performing orthogonalization processing on the environment variable data, and removing the projection components of each environment variable on the tide protection base from the original environment variable to obtain environment variables orthogonal to the tide protection base in the mathematical sense; Step 4, based on the orthogonalized environment variables, establishing an environment response model by using ridge regression analysis to calculate the influence of environmental disturbance on gravity measurement; Step 5, compensating the original gravity measurement data according to the gravity variation caused by the environmental disturbance to obtain the compensated gravity measurement result.

[0014] By constructing a tide component protection base, orthogonalizing the environment variables and introducing a regularization regression mechanism, the tide component is fundamentally avoided from being misabsorbed in the compensation process, the stability of the regression coefficient is significantly improved, and the time lag effect of the environmental disturbance is fully considered. The method is suitable for various gravity measurement devices including miniaturized gravity meters, and can realize high-precision and long-term stable gravity observation in complex environments.

[0015] Preferably, in step 3, the orthogonalization processing on the environment variable data comprises Gram-Schmidt orthogonalization of the environment variables, so that the orthogonalized environment variables satisfy the mutual orthogonality in the inner product sense.

[0016] Preferably, in step 4, the ridge regression analysis introduces a regularization constraint term in the least square regression objective function to suppress the multicollinearity between the environment variables and improve the stability of the regression coefficient in the environment response model.

[0017] Preferably, before step 3 or step 4, a time delay term is introduced to the environment variables, and the optimal time delay corresponding to each environment variable is determined through correlation analysis or regression error minimization criterion.

[0018] Overall, compared with the prior art, the above technical solutions conceived by the present application have the following beneficial effects: 1. The present application realizes the effective separation of tidal components and environmental disturbances in mathematical space by constructing a tidal component protection base and performing strict orthogonalization processing on environmental variables, avoiding the problem that tidal signals are incorrectly absorbed or weakened due to spectral overlap in traditional compensation methods. This feature ensures that the amplitude and phase of the Earth tide signal remain physically consistent, making the gravity measurement results more reliable and accurate, especially for long-term continuous observation tasks that are sensitive to tidal characteristics.

[0019] 2. After orthogonalization regression, the present application further introduces a ridge regression (L2 regularization) method to address the problem of multicollinearity among environmental variables. By adding an L2 regularization term (λ) during regression, the regression coefficients are effectively constrained, avoiding problems such as coefficient instability, sign reversal, and overfitting in traditional least squares methods. Ridge regression ensures the stability of the regression coefficients through regularization, significantly improving the stability and repeatability of the model under different observation periods and environmental conditions.

[0020] 3. The present application introduces an adaptive time lag search mechanism, which analyzes the correlation between environmental variables and gravity measurement data to automatically identify the optimal time lag of environmental factors such as air pressure loading, heat conduction, and tilt changes affecting gravity measurement, thereby establishing an environmental compensation model that better conforms to the actual physical process. Compared with traditional compensation methods that assume immediate response of environmental influences, the present application can effectively avoid systematic compensation bias caused by neglecting environmental response time lag, especially for gravity measurement systems with slow environmental control processes, significant structural thermal response, or obvious inertia characteristics.

[0021] 4. The orthogonalization regression compensation method proposed by the present application has good universality and can be applied to various gravity measurement systems, including MEMS gravimeters, quartz spring gravimeters, and absolute gravimeters. By establishing a unified mathematical constraint mechanism for environmental variables, this method is suitable for instruments of different structures and packaging forms, facilitating the development of a universal gravity measurement environmental compensation scheme.

[0022] 5. The miniaturized MEMS gravimeter of the present application embodiment adopts a compact structure design and has low power consumption characteristics. Combined with the environmental compensation method of the present application, its long-term stability and tidal tracking capability in complex environments are significantly improved, making it suitable for applications such as unmanned aerial vehicle carrying, portable measurement, deep well monitoring, and other scenarios sensitive to size and weight. The results show that this method not only improves the compensation accuracy but also fully releases the application potential of miniaturized gravimeters.

[0023] 6. Through the synergistic effect of key technologies such as tidal component separation, multicollinearity suppression, and environmental time delay correction, this invention effectively overcomes the systematic defects of traditional environmental compensation methods, significantly improves the long-term stability, compensation accuracy, and environmental adaptability of gravity measurement, and provides a solid technical foundation for the promotion and application of gravity measuring instruments in multiple fields. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a miniaturized MEMS gravimeter; Figure 2 This is a flowchart of environmental compensation methods; Figure 3 It is a comparison of gravity data before and after environmental compensation: (a) Comparison of gravity data before compensation with theoretical tides; (b) Comparison of gravity data after compensation with theoretical tides. In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, including: 1, gravity sensor chip; 2, housing; 3, multi-stage temperature control system; 4, processor; 5, electromagnetic shielding housing; 6, inclinometer; 7, leveling feet; 8, barometer. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0026] This invention provides a compact, miniaturized MEMS gravimeter, such as Figure 1As shown, the device includes a gravity sensor chip 1, a housing 2, a multi-stage temperature control system 3, a processor 4, an electromagnetic shielding shell 5, a tiltmeter 6, leveling feet 7, and a barometer 8. The gravity sensor chip 1 and the barometer 8 are encapsulated together inside the housing 2. The barometer 8 is used to detect the air pressure information inside the housing. The multi-stage temperature control system 3 is installed outside the housing 2 for graded active temperature control of the gravity sensor chip 1. The electromagnetic shielding shell 5 is located on the outermost side to suppress external electromagnetic interference. The leveling feet 7 are located at the bottom for leveling the MEMS gravimeter. The tiltmeter 6 is located on the gravity sensor chip. Below 1, and mounted on the same mechanical reference structure as the gravity sensing chip 1, so that the attitude change measured by the inclinometer 6 is consistent with the attitude change of the gravity sensing chip 1, for detecting the attitude tilt information of the MEMS gravimeter. The processor 4 is electrically connected to the gravity sensing chip 1, the multi-level temperature control system 3, the inclinometer 6 and the barometer 8, for receiving the temperature signal obtained by the multi-level temperature control system 3, the air pressure signal obtained by the barometer 8 and the attitude tilt signal obtained by the inclinometer 6, and performing error compensation processing on the gravity measurement signal output by the gravity sensing chip 1 according to the above environmental information.

[0027] Specifically, the casing material is either ceramic or Kova alloy. Ceramic materials possess a low coefficient of thermal expansion, good insulation, and extremely low gas permeability; their thermal expansion behavior is similar to that of sensitive structures, reducing stress accumulation caused by temperature changes. Kova alloy materials, on the other hand, exhibit excellent airtightness, high mechanical strength, and good weldability, forming a stable and reliable encapsulation interface. Encapsulation methods can include hermetically sealed encapsulation or vacuum encapsulation to meet the pressure isolation requirements of different application scenarios. Furthermore, this gravimeter can integrate a pressure detection element within the encapsulation to monitor internal and external pressure changes, providing auxiliary information for subsequent environmental compensation algorithms.

[0028] To further enhance thermal stability, this invention employs a multi-layered temperature control structure arranged from the inside out. An external temperature control system precisely regulates the operating temperature of the MEMS gravimeter, ensuring temperature stability under complex environmental conditions. Through the synergistic effect of different temperature control layers, the multi-layered temperature control stabilizes the operating temperature of the sensing chip under varying external temperatures, effectively suppressing the impact of external temperature changes on the internal sensitive structure of the instrument. This prevents structural stress or stiffness mismatch caused by temperature differences, thereby improving thermal stability. Each temperature control layer can be set with progressively increasing small temperature differences, forming a temperature buffer zone between adjacent layers to prevent sudden temperature changes from being directly transmitted to the sensitive structure. Each temperature control layer can employ different temperature control circuits, thermal management materials, or insulation structures to achieve a combination of precision and buffered temperature control, further reducing the transmission of temperature disturbances within the device. The number of layers in the multi-layered temperature control system and the temperature differences between layers can be flexibly configured according to actual application requirements to achieve a balance between different accuracy requirements and energy consumption indicators.

[0029] To suppress tilt errors caused by attitude changes, this gravimeter can integrate a tilt detection unit for real-time monitoring of the instrument's attitude. This tilt detection unit provides tilt angle information for tilt compensation during data processing. For mechanical leveling, this invention can utilize adjustable structures such as leveling legs, long platforms, or tripods to mechanically adjust the instrument's attitude, thereby reducing measurement deviations caused by tilt and improving the system's measurement reliability in different terrains and deployment environments. The aforementioned tilt detection and leveling methods are not limited to specific structures and have wide applicability. Furthermore, the gravimeter's signal processing circuitry and high-precision temperature control circuitry are all fixedly installed within an electromagnetic shielding housing to improve mechanical stability and reduce external interference.

[0030] The gravimeter of this invention features a compact design, small size, and light weight, making it easy to carry and deploy quickly. This design is suitable for various applications such as portable geological exploration, deep well monitoring, and UAV-borne applications, and exhibits excellent low power consumption, making it particularly suitable for long-term field operations or monitoring tasks requiring extended operation. This compact design not only optimizes the size and weight of the device but also ensures high efficiency and stability, providing great flexibility for different application environments. The overall structure can be designed within a volume range of approximately 10 cm (e.g., no larger than approximately 10 × 10 × 10 cm³), and the overall weight can be controlled to within approximately 1 kg. This compact structure gives the device the characteristics of small size, light weight, and low power consumption, facilitating rapid deployment and long-term operation in various scenarios such as deep well observation, geological exploration, UAV payload platforms, and portable field measurements. Those skilled in the art can adjust the size and weight according to different application requirements; this embodiment does not constitute a limitation of the invention.

[0031] To improve the accuracy and long-term stability of gravity measurement systems in complex environments, this invention proposes a gravity measurement environment compensation method based on orthogonal regression, such as... Figure 2 As shown, it includes the following steps: S1, First, synchronous data acquisition is performed on the MEMS gravimeter to obtain raw gravity measurement data and corresponding environmental variable data. The raw gravity measurement data is represented as follows: G (t), environmental variables include air pressure data. P ( t Temperature data T ( t ) and tilt data θ ( t The above data is sampled and recorded according to a unified time benchmark to ensure time consistency between data.

[0032] S2. After data acquisition is completed, in order to avoid the low-frequency tidal signal being mistakenly absorbed by environmental variables during the environmental compensation process, this invention constructs a tidal protection basis before environmental compensation modeling. This basis is used to characterize the main variation characteristics of solid tides in gravity observation data and to serve as the reference basis space for subsequent orthogonalization processing.

[0033] When theoretical solid tide data is available, this invention uses the theoretical tide sequence calculated by the theoretical tide model as the tidal reference signal. Let the theoretical tide sequence be represented as: Tide( t To further enhance the ability to characterize tidal variation trends and phase information, this invention also introduces the first-order time derivative of the theoretical tidal sequence as a component of the tidal protection basis, the expression of which is: Therefore, the tidal protection basis can be represented as a set of the following basis functions: .

[0034] Among them, Tide ( t The first basis function is used to characterize the main amplitude variation characteristics of the tidal signal, while its first time derivative is used to characterize the phase variation and rate of change characteristics of the tidal signal. By introducing the above two basis functions simultaneously, the amplitude and phase of the tidal signal can be jointly protected during the compensation modeling process, thereby avoiding amplitude attenuation or phase distortion of the tidal signal during environmental compensation.

[0035] In situations where theoretical solid tidal data is unavailable, this invention constructs a tidal protection basis by selecting multiple typical tidal cycles. Specifically, based on the main periodic characteristics of tidal signals, typical tidal cycles with periods of 8 hours, 12 hours, 12.4206 hours, and 24 hours are selected, and the corresponding sine and cosine functions are used as basis functions to construct an orthogonal trigonometric function form of the tidal protection basis.

[0036] Let the i-th tidal period be Ti, and the corresponding angular frequency be:

[0037] The tidal basis function corresponding to this period can be expressed as:

[0038] By constructing the above sine and cosine functions for the selected multiple tidal periods respectively, the set of tidal protection bases can be obtained:

[0039] The Ti includes 8 hours, 12 hours, 12.4206 hours, and 24 hours, and the corresponding basis functions are used to characterize the main periodic components of the tidal signal and their phase information.

[0040] To improve the orthogonality between basis functions, under discrete sampling conditions, the trigonometric function basis can be normalized or orthogonalized to reduce the correlation between different tidal period components. The tidal protection basis constructed in this way can effectively model and protect the main tidal components in gravity measurement data without the input of theoretical tidal sequences.

[0041] S3. After constructing the tidal protection basis, this invention orthogonalizes the environmental variables. Using the Gram-Schmidt orthogonalization method, environmental variables such as air pressure, temperature, and tilt are projected onto the orthogonal complement space of the tidal protection basis, making them mathematically completely independent of the tidal signal, thereby avoiding the tidal component being mistakenly absorbed by the environmental variables in the subsequent regression compensation process.

[0042] With any environment variable X (t) (wherein) X (t) can represent P (t), T (t) or θ (t) is first projected onto the tidal protection base B to obtain its tidal-related components:

[0043] By subtracting the projected components from the original environment variables, the orthogonalized environment variables are obtained:

[0044] This ensures that the orthogonalized environment variables satisfy:

[0045] That is, after the above processing, the resulting environmental variables It is mathematically orthogonal to the tidal signal, providing a foundation for subsequent environmental compensation models based on orthogonalized regression.

[0046] S4. Considering that the influence of environmental factors on gravity measurements usually has a time lag, a time delay correction is introduced for each environmental variable after orthogonalization.

[0047] Specifically, by searching environment variables within a preset time window. With gravity measurement data G ( t The time delay value with the highest correlation is used to perform time shift processing on environmental variables to more realistically reflect the actual impact of environmental factors on gravity measurement.

[0048] S5. After completing orthogonalization and time delay correction, an expression model for the impact of environmental disturbances on gravity measurements is established. The change in gravity caused by environmental disturbances is expressed as:

[0049] in, as well as These represent the compensation coefficients for air pressure, temperature, and tilt on the gravity measurement, respectively.

[0050] In addition, to address the instrument zero-point drift and nonlinear variations observed in long-term observations, orthogonal polynomial trend terms and necessary environmental quadratic terms (such as barometric quadratic terms) can be added to the regression model. P ², Temperature quadratic term T ², Inclined quadratic term ²), used to model the slow drift of the instrument and the nonlinear response to environmental factors. All additional items have been tidal-protected orthogonalized to ensure that the integrity of the tidal waveform is not compromised.

[0051] S6. To address the instability of regression coefficients caused by multicollinearity, this invention employs ridge regression (L2 regularization) to solve for the environmental response coefficients. This is achieved by adding a regularization term to the least squares solution. This can effectively suppress unstable behaviors such as regression coefficient divergence and sign reversal. The ridge regression objective function is defined as:

[0052] in G These are the values ​​measured by the gravimeter. These are the environment variables after orthogonalization. The coefficients to be compensated for by gravity for environmental variables. This is a regularization parameter used to suppress multicollinearity among environmental variables.

[0053] Its analytical solution is:

[0054] By utilizing singular value decomposition (SVD) and Tikhonov regularization techniques, the numerical stability of the regression solution can be further improved, ensuring that the compensation model remains consistent across different observation periods.

[0055] S7. Based on the established environmental disturbance compensation model, the original gravity measurement data is compensated to obtain the compensated gravity measurement results.

[0056]

[0057] Meanwhile, by analyzing the linear relationship between the compensated gravity data and the theoretical tides, robust regression is performed within the large tidal range to adaptively correct the scaling factor of gravity measurements, thereby further improving measurement accuracy.

[0058] S8, Figure 3 The comparison of gravity data before and after environmental compensation is shown. (a) shows the gravity data before compensation. G ( t ) and theoretical tidal Tide ( t (a) shows a correlation of only 0.514. (b) shows the gravity data after orthogonal regression and environmental compensation. After compensation, the correlation between gravity data and theoretical tides was significantly improved to 0.978, which significantly improved the accuracy of gravity measurement.

[0059] Through the above steps, the environmental compensation method of the present invention can effectively solve the problems that traditional methods cannot overcome, such as tidal component misabsorption, multicollinearity and environmental time delay, and is applicable to various gravity measurement systems, including MEMS gravimeters.

[0060] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. It should be noted that the terms "in one embodiment," "for example," and "again" in this invention are intended to illustrate the invention and are not intended to limit the invention.

[0061] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A miniaturized MEMS gravimeter, characterized in that, The system includes a gravity sensor chip (1), a housing (2), a multi-stage temperature control system (3), a processor (4), an electromagnetic shielding shell (5), a tiltmeter (6), leveling feet (7), and a barometer (8). The gravity sensor chip (1) and the barometer are encapsulated together inside the housing (2). The barometer is used to detect the air pressure information inside the housing (2). The multi-stage temperature control system (3) is set on the outside of the housing (2) to perform graded active temperature control on the gravity sensor chip (1). The electromagnetic shielding shell (5) is set on the outermost side to suppress external electromagnetic interference. The leveling feet are set on the bottom side to... The MEMS gravimeter is leveled. The inclinometer (6) is located below the gravity sensing chip (1) and is used to detect the attitude tilt information of the MEMS gravimeter. The processor (4) is electrically connected to the gravity sensing chip (1), the multi-level temperature control system (3), the inclinometer (6) and the barometer (8). It is used to receive the temperature signal obtained by the multi-level temperature control system (3), the air pressure signal obtained by the barometer (8) and the attitude tilt signal obtained by the inclinometer (6), and to perform error compensation processing on the gravity measurement signal output by the gravity sensing chip (1) according to the above environmental information.

2. The MEMS gravimeter as described in claim 1, characterized in that, The shell (2) is made of ceramic or Kova alloy, and the shell is vacuum-sealed or atmospheric pressure-sealed.

3. The MEMS gravimeter as described in claim 1, characterized in that, The multi-level temperature control system includes at least two temperature control structures. Each temperature control structure is equipped with a heating film and a temperature detection device, and a heat insulation layer is provided between adjacent temperature control structures. The temperature control accuracy is gradually improved from the outside to the inside, so as to achieve system miniaturization while ensuring temperature control performance.

4. The MEMS gravimeter as described in claim 1, characterized in that, The gravity sensor chip, housing, multi-stage temperature control system, and processor are arranged around the same central axis and form a multi-layer integrated arrangement in the axial direction.

5. A gravity measurement environment compensation method based on orthogonal regression, characterized in that, Includes the following steps: Step 1: Collect raw gravity measurement data and environmental variable data of the miniaturized MEMS gravimeter according to any one of claims 1-4, wherein the environmental variable data includes air pressure data, temperature data and tilt data; Step 2: Construct a tidal protection base to characterize the main variation features of solid tides in the original gravity measurement data; Step 3: Perform orthogonalization processing on the environmental variable data. Remove the projection components of each environmental variable onto the tidal protection base from the original environmental variables to obtain environmental variables that are mathematically orthogonal to the tidal protection base. Step 4: Based on the orthogonalized environmental variables, ridge regression analysis is used to establish an environmental response model and calculate the impact of environmental disturbances on gravity measurements. Step 5: Based on the change in gravity caused by the environmental disturbance, compensate the original gravity measurement data to obtain the compensated gravity measurement result.

6. The gravity measurement environment compensation method as described in claim 5, characterized in that, The tidal protection base is composed of a theoretical solid tidal sequence and its time derivative, or of orthogonal trigonometric functions corresponding to multiple preset tidal periods.

7. The gravity measurement environment compensation method as described in claim 5, characterized in that, In step 3, the orthogonalization process performed on the environmental variable data includes Gram-Schmidt orthogonalization of the environmental variables.

8. The gravity measurement environment compensation method as described in claim 5, characterized in that, In step 4, the environmental response model is established using ridge regression analysis. By introducing a regularization constraint term into the least squares regression objective function, multicollinearity among environmental variables is suppressed.

9. The gravity measurement environment compensation method as described in claim 5, characterized in that, Before step 3 or step 4, a time delay term is introduced for the environmental variables, and the optimal time delay for each environmental variable is determined by correlation analysis or regression error minimization criteria.

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