A method for calibrating absolute acceleration of gravity

Abstract

The application discloses an absolute gravity acceleration calibration method, relates to the field of acceleration calibration, and mainly has the following scheme: a plurality of candidate regions are preliminarily determined by collecting data of polar regions; bedrock stability data are collected to calculate a bedrock stability coefficient of each candidate region, and a candidate region meeting requirements is screened; a gravity standard platform is cast at a site target point; equipment guarantee reliability is calculated based on operation data, and whether the equipment state meets standards is judged according to the equipment guarantee reliability; when the equipment state meets the standards, gravity measurement data quality factors are calculated according to gravity measurement data, and whether the data collected by the gravity measurement equipment meets requirements is judged; when the collected data meets the requirements, gravity acceleration calibration values are further calculated; by systematically considering factors such as bedrock stability, equipment guarantee reliability, gravity data quality factors and interference suppression coefficients, the scheme can significantly improve the accuracy and reliability of absolute gravity acceleration calibration.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of acceleration calibration, in particular to an absolute gravity acceleration calibration method. BACKGROUND

[0002] Earth gravity field data is a country's basic data, strategic data. Precise measurement of the Earth's gravitational field has very important scientific significance to the fields of metrology science, earthquake prevention and disaster reduction, geodesy, geophysics, etc. The polar ocean rights have increasingly attracted the attention of many developed countries in the world, and gravity measurement, as a basic parameter, plays a crucial role in polar scientific investigation, navigation, resource exploration, etc. At present, gravity measurement is the basis for studying the Earth's gravitational field, crustal vertical movement, sea level change, height datum, climate change and geoid change, ice cover change, etc. in the Antarctic region.

[0003] The existing absolute gravity acceleration calibration method has some defects and deficiencies. First, in complex environments such as the polar region, the existing method lacks a comprehensive evaluation of the candidate area, especially the consideration of bedrock stability. This may lead to unreasonable site selection of the gravity standard platform, thereby introducing larger measurement errors and data instability.

[0004] Secondly, the existing technology is not comprehensive and accurate in evaluating the reliability of equipment operation, and lacks effective equipment reliability calculation methods. This makes it difficult to accurately judge the running state of the equipment in harsh environments, affecting the continuity of the calibration work and the reliability of the data.

[0005] Thirdly, the existing method has deficiencies in data quality control, and the quality evaluation of gravity measurement data is not detailed enough, which cannot effectively identify and exclude low-quality data, thereby affecting the accuracy of the calibration results. Finally, the existing technology is relatively rough in dealing with environmental interference, and fails to fully utilize comprehensive indicators such as interference suppression coefficients to make fine corrections on environmental factors, resulting in calibration results being easily disturbed by environmental factors and limited precision. SUMMARY

[0006] (I) Technical problems solved

[0007] In view of the deficiencies of the existing technology, the present application provides an absolute gravity acceleration calibration method to solve the technical problems that the existing absolute gravity acceleration calibration method has obvious defects in candidate area site selection, equipment operation reliability evaluation, data quality control, and environmental interference correction, etc., and is difficult to meet the high-precision calibration requirements in complex environments such as the polar region.

[0008] (II) Technical solutions

[0009] To achieve the above purpose, the present application is implemented by the following technical solutions: an absolute gravity acceleration calibration method, comprising:

[0010] Step 1: By collecting geological structure data, topographic data, and meteorological data of the polar regions, several candidate areas are initially identified within the existing station areas;

[0011] Step 2: Collect bedrock stability data for candidate areas and calculate the bedrock stability coefficient for each candidate area. ;

[0012] Step 3: Set a bedrock stability threshold and compare the bedrock stability coefficients of multiple candidate regions. The regions were compared with the bedrock stability threshold to select candidate regions that met the requirements.

[0013] Step 4: Construct a gravity standard platform at the selected target site and install gravity measurement equipment and outdoor safety system;

[0014] Step 5: Collect operational data from the gravity measurement equipment and outdoor support system using data acquisition devices, and calculate the equipment's reliability based on the operational data. And based on the equipment's reliability Determine whether the equipment status meets the standards;

[0015] Step Six: Once the equipment meets the standards, collect gravity measurement data from the gravity measuring equipment and calculate the gravity data quality factor based on the gravity measurement data. And based on gravity data quality factor Determine whether the data collected by the gravity measuring equipment meets the requirements;

[0016] Step 7: When the collected data meets the requirements, acquire the interference data, and through the interference data analysis model, obtain the solid tide correction residual value, the uncorrected amount of ice sheet mass change, and the pressure disturbance correction residual value, and further calculate the total environmental factor correction value. Interference suppression coefficient and equipment calibration correction items The gravitational acceleration calibration value was calculated based on the above parameters. .

[0017] In the preferred embodiment of the above-mentioned absolute gravity acceleration calibration method, in step one: the bedrock area surrounding the station area is selected based on geological structural data as the first selection criterion;

[0018] Based on topographic data, areas with a vertical elevation difference greater than 10m from the standard points of the original surveying and mapping bureau were selected as the second screening criterion.

[0019] Based on meteorological data, areas with wind force levels less than level 8 were selected as the third screening criterion.

[0020] Regions that simultaneously meet screening criteria one, screening criteria two, and screening criteria three are selected as candidate regions.

[0021] In a preferred embodiment of the aforementioned absolute gravitational acceleration calibration method, the bedrock stability data includes bedrock fracture density. and ice flow rate value Specifically:

[0022] Within the selected candidate area, several observation plots of unit area are delineated. Measuring tools are used to measure bedrock fissures within the plots. The bedrock fissure density is calculated by counting the number of fissures within each plot and dividing by the plot area. ;

[0023] Global Positioning System (GPS) monitoring points are installed on the surface of ice bodies in polar regions to record the position coordinates of the ice bodies at different times. The displacement distance of the ice bodies between two time points is calculated and divided by the time interval to obtain the ice flow velocity. The average of the acquired ice flow velocities is then calculated as the ice flow velocity value for the measurement cycle. .

[0024] In the preferred embodiment of the above-mentioned absolute gravitational acceleration calibration method, based on the bedrock fracture density... and ice flow rate value Calculate the bedrock stability index The formula used is as follows:

[0025] ;

[0026] Where e is the base of the natural logarithm, The duration of the ice flow rate detection.

[0027] In a preferred embodiment of the above-mentioned absolute gravity acceleration calibration method, the bedrock stability coefficients of multiple candidate regions are compared with the bedrock stability threshold. When the bedrock stability coefficient... When the bedrock stability coefficient is ≥ the bedrock stability threshold, the corresponding candidate region meets the requirements; when the bedrock stability coefficient is ≥ the bedrock stability threshold, the corresponding candidate region meets the requirements. If the value is less than the bedrock stability threshold, then the corresponding candidate region does not meet the requirements;

[0028] When multiple candidate regions meet the requirements, the bedrock stability coefficients of these candidate regions are... Compare and select the bedrock stability coefficient The candidate region corresponding to the maximum value is used as the target point for site selection.

[0029] In the preferred embodiment of the above-mentioned absolute gravitational acceleration calibration method, the operating data includes at least the actual operating parameter values ​​of the gravity measuring equipment. And actual environmental parameter values; actual operating parameter values At least the operating voltage of the gravity measuring equipment, the operating temperature of the equipment components, and the power frequency of the power supply device in the outdoor support system are included. The actual environmental parameter values ​​include the ambient temperature and ambient air pressure of the environment where the gravity measuring equipment is located.

[0030] In the preferred embodiment of the above-mentioned absolute gravitational acceleration calibration method, reliability is ensured by operating data calculation equipment. The formula used is as follows:

[0031] ;

[0032] in, The first of the gravity measuring devices Actual operating parameter values; The first of the gravity measuring devices Parameter setting value; The first of the gravity measuring devices The allowed fluctuation range for this parameter; among which, The serial number represents the parameter of the gravity measuring equipment, and its value is a positive integer. This refers to the number of types of equipment parameters; It is the base of the natural logarithm. The standard deviation of temperature fluctuation in the area where the gravity measuring equipment is located; The threshold value representing the standard deviation of temperature fluctuation in the area where the gravity measuring equipment is located;

[0033] Ensure equipment reliability Compared with the equipment assurance reliability threshold, when the equipment assurance reliability... If the equipment status is ≥ the equipment reliability threshold, then the equipment status is considered to meet the standard.

[0034] In a preferred embodiment of the above-mentioned absolute gravitational acceleration calibration method, the gravity measurement data includes gravity value error. and vacuum deviation ;

[0035] The gravity data quality factor is calculated using gravity measurement data. The formula used is as follows:

[0036] ;

[0037] in, Indicates the first step in the measurement process Error in the gravity value measured in this instance; This represents the maximum permissible dispersion of gravitational acceleration; Indicates the first step in the measurement process Vacuum deviation in this measurement; Indicates the standard vacuum level value; This represents the sequence number of measurements during the measurement process, and its value is a positive integer. Indicates the maximum number of measurements;

[0038] Gravity data quality factor Compared with the gravity data quality threshold, when the gravity data quality factor When the data quality threshold is ≥, the data collected by the gravity measuring device is deemed to meet the requirements.

[0039] In the preferred embodiment of the above-mentioned absolute gravitational acceleration calibration method, the interference data includes solid tide interference data, ice sheet mass interference data, air pressure disturbance data, and equipment interference data.

[0040] Input solid tide interference data into solid tide modeling software to calculate solid tide correction values. The actual measured gravitational acceleration value is compared with the solid tide correction value calculated by the model. Subtracting the two yields the solid moisture correction residual. ;

[0041] The ice sheet mass disturbance data is input into the gravity effect calculation model to obtain the change value of gravitational acceleration. Subtracting the change in gravitational acceleration from the measured value of gravitational acceleration yields the uncorrected amount. ;

[0042] Input the air pressure disturbance data into the air pressure-gravity relationship model to calculate the theoretical value of the change in gravitational acceleration caused by the change in air pressure. The actual measured value of gravitational acceleration is subtracted from the theoretical value of the change in gravitational acceleration to obtain the residual value of the pressure disturbance correction. ;

[0043] Equipment interference data includes zero-point drift value Z and linear drift value L. A zero-point drift correction term Zcorrection is obtained based on the zero-point drift value Z, and Zcorrection = Z. The linear drift coefficient Lcorrection is calculated based on the linear drift value L, using the formula: Lcorrection = L * t, where t is the measurement time interval. Finally, the zero-point drift correction term Zcorrection and the linear drift coefficient Lcorrection are summed to obtain the equipment calibration correction term. .

[0044] In the preferred embodiment of the above-mentioned absolute gravitational acceleration calibration method, the solid tide correction residual value is... Uncorrected amount and pressure disturbance correction residuals Summation calculation yields the total environmental factor correction value. ;

[0045] Based on solid tide correction residuals Uncorrected amount and pressure disturbance correction residuals Calculate the interference suppression coefficient The formula used is as follows:

[0046] ;

[0047] The initial measurement value is obtained by averaging the gravitational acceleration values ​​obtained from multiple actual measurements. ;

[0048] Based on the total environmental factors correction value Interference suppression coefficient Equipment calibration correction items and initial measurement value Calculate the calibration value of gravitational acceleration The formula used is:

[0049] .

[0050] (III) Beneficial Effects

[0051] This invention provides an absolute gravitational acceleration calibration method, which has the following beneficial effects:

[0052] (1) By collecting geological structure data, topographic data, and meteorological data of the polar regions, and combining them with the existing station area, several candidate areas were initially identified. Furthermore, bedrock stability data of the candidate areas were collected, and the bedrock stability coefficient of each candidate area was calculated. This coefficient was then compared with a set bedrock stability threshold to screen for suitable candidate areas. This process effectively avoids setting up gravity standard platforms in areas with poor geological conditions and unstable bedrock, thus ensuring that the installation foundation of gravity measurement equipment has sufficient stability and reliability. For example, in the complex geological environment of the polar regions, there may be areas with well-developed bedrock fissures and frequent glacial activity. The geological instability of these areas can adversely affect the long-term stable operation of gravity measurement equipment. Through this site selection process, areas with good geological conditions and stable bedrock can be accurately screened, laying a solid foundation for subsequent high-precision gravity acceleration calibration work.

[0053] (2) The operation data of the gravity measurement equipment and the outdoor support system are collected through a data acquisition device. The equipment support reliability is calculated based on the operation data, and the equipment status is judged to meet the standards based on the equipment support reliability. This measure can comprehensively and in real time monitor the operation status of the equipment and promptly detect potential problems in the operation process, such as voltage fluctuations, temperature changes, and frequency deviations. For example, in the harsh climate conditions of polar regions, the equipment may be affected by natural factors such as extreme low temperatures, blizzards, and strong winds, leading to a decline in equipment performance or even failure. By calculating the equipment support reliability, the operational stability and reliability of the equipment in such complex environments can be quantitatively assessed. When the reliability is lower than the set standard, maintenance measures are taken in a timely manner to ensure that the equipment is always in good operating condition, thereby ensuring the continuity and accuracy of gravity acceleration calibration work.

[0054] (3) Once the equipment meets the standards, gravity measurement data from the gravity measuring equipment is collected, and the gravity data quality factor is calculated based on the gravity measurement data. The gravity data quality factor is then used to determine whether the data collected by the gravity measuring equipment meets the requirements. This step allows for strict quality control of the collected gravity data, eliminating low-quality data caused by equipment errors, environmental interference, and other factors, ensuring that the gravity data used for calibration has high accuracy and high reliability. For example, during gravity measurement, factors such as surrounding electromagnetic interference and mechanical vibration may affect the collected data, causing abnormal fluctuations. By calculating the gravity data quality factor, the quality of the data can be quantitatively evaluated. For gravity data that does not meet the quality standards, the reasons can be analyzed in a timely manner and the data can be re-collected, thereby ensuring the accuracy and reliability of the final gravity acceleration calibration results.

[0055] (4) When the collected data meets the requirements, interference data is acquired, and through the interference data analysis model, the residual values ​​of solid tide correction, the uncorrected amount of ice sheet mass change, and the residual values ​​of air pressure disturbance correction are obtained. The total environmental factor correction value, interference suppression coefficient, and equipment calibration correction term are further calculated, and the gravity acceleration calibration value is calculated based on the above parameters. This process can comprehensively consider the influence of multiple environmental factors on gravity acceleration measurement and accurately correct them, thereby significantly improving the accuracy of the calibration results. For example, environmental factors such as solid tide, ice sheet mass change, and air pressure disturbance have a significant impact in polar regions, which can lead to small changes in gravity acceleration. By establishing an interference data analysis model, these environmental interference factors can be quantitatively analyzed and corrected, effectively eliminating their influence on gravity acceleration calibration results, making the calibrated gravity acceleration value closer to the true value, and providing high-precision gravity standard data for geoscience research and resource exploration in polar regions. Attached Figure Description

[0056] Figure 1This is a schematic diagram illustrating the steps of an absolute gravitational acceleration calibration method according to the present invention. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0058] Example 1

[0059] Please see Figure 1 This invention provides a method for calibrating absolute gravitational acceleration, comprising:

[0060] Step 1: By collecting geological structure data, topographic data and meteorological data of the polar region, several candidate areas are initially identified within the existing station area.

[0061] Step 101: Select bedrock areas around the station area based on geological structure data as screening criteria; for example, within a 10-kilometer radius of the existing station area, to facilitate the transportation of materials.

[0062] Step 102: Based on the terrain data, select areas with a vertical elevation difference greater than 10m from the standard points of the original surveying and mapping bureau as the second screening criterion; adjustments can be made with reference to industry standards in this field.

[0063] Step 103: Based on meteorological data, select areas with wind speeds less than level 8 as screening criterion three; adjustments can be made with reference to industry standards in this field.

[0064] Step 104: Select regions that simultaneously meet screening criteria one, screening criteria two, and screening criteria three as candidate regions.

[0065] Step 2: Collect bedrock stability data for candidate areas and calculate the bedrock stability coefficient for each candidate area. .

[0066] It should be noted that in calculating the bedrock stability coefficient... During the process, all parameters involved in each calculation step need to be normalized and preprocessed to eliminate the dimensions of different parameters, so as to facilitate subsequent formula calculations.

[0067] Bedrock stability data includes bedrock fracture density. and ice flow rate value ;

[0068] Step 201: Within the selected candidate area, delineate several observation plots with unit areas, such as 1 square meter, 2 square meters, etc. Using tools such as a geological hammer and measuring ruler, carefully observe and measure the bedrock fissures within the plots. Record the location, orientation, and length of the fissures. Calculate the bedrock fissure density by counting the number of fissures within each plot and dividing by the plot area. For example, if 8 cracks are observed in a 2-square-meter sample plot, then... Items per square meter.

[0069] It should be noted that remote sensing imagery, such as aerial remote sensing imagery or satellite remote sensing imagery, such as QuickBird and WorldView satellite imagery, can also be used to analyze the bedrock surface in polar regions. Image processing software is used to preprocess the images to enhance their quality. Then, fracture identification algorithms, such as fracture extraction algorithms based on grayscale and texture features, are used to identify bedrock fractures in the images. After the extracted fractures are vectorized, GIS software is used to calculate the number of fractures per unit area, thereby obtaining... The more fissures there are, the worse the integrity of the bedrock and the lower its stability. This method is suitable for large-area regional surveys and can obtain a large amount of fissure information in a short time.

[0070] Step 202: Install GPS monitoring points on the ice surface in the polar region. These monitoring points can consist of GPS receivers, data storage devices, and power sources (such as solar panels or other power sources suitable for the polar environment). The GPS receivers can record the position coordinates of the ice body at different times. By periodically collecting data from the monitoring points, calculating the displacement distance of the ice body between two time points, and dividing by the time interval, the ice flow velocity can be obtained. The average of the acquired ice flow velocities is then calculated as the ice flow velocity value for the measurement cycle. Ice flow velocity reflects the speed at which ice masses such as glaciers or ice sheets move per unit time. In polar regions, the movement of ice masses can cause erosion and other effects on bedrock. The greater the ice flow velocity, the stronger the destructive effect on bedrock may be, thus affecting the stability of the bedrock.

[0071] For example, during a monitoring period of one year, if the ice body moves from location A to location B, with a displacement distance of 4 meters, then... Meters per year.

[0072] Step 203: Based on bedrock fracture density and ice flow rate value Calculate the bedrock stability index The formula used is as follows:

[0073] .

[0074] Where e is the base of the natural logarithm, The duration of the ice flow rate detection.

[0075] It should be noted that the bedrock fracture density in the formula... This reflects the integrity of the bedrock; the more fissures, the less stable the bedrock; ice flow velocity value The potential erosive and destructive effects of glacial activity on bedrock were considered; the greater the ice flow velocity and the longer the monitoring time... The longer the length, the greater the impact on bedrock stability. This can be expressed using an exponential function. and In summary, this is quantified as a bedrock stability index. The denominators 5 and 10 in the formula are used to calculate the bedrock fracture density. Ice flow velocity time term The coefficients are normalized. Their design is primarily based on empirical summaries of factors influencing bedrock stability and the standardization requirements of practical applications. By setting such a denominator, parameters of different dimensions and orders of magnitude can be normalized. and By unifying them to a suitable scale range, their combination can be used to calculate the bedrock stability index within a reasonable exponential function framework.

[0076] Extensive data has been accumulated regarding the impact of bedrock fracture density on rock mass stability in geological research and engineering practice. Studies have shown that when bedrock fracture density... When the number of fractures is less than 5 per square meter, the bedrock exhibits good stability. This is because at lower fracture densities, the rock mass maintains relatively good integrity, and the impact of fractures on stability-related factors such as the rock mass's bearing capacity is relatively small. Therefore, setting the denominator to 5 allows for... When it equals 5 strips / square meter, the formula is as follows: The denominator is set to 1 for ease of subsequent index calculations and standard comparisons; the erosive effect of ice flow velocity on bedrock is a long-term cumulative process. Ice flow velocity is measured in meters per year, and monitoring duration is typically measured in years. When comprehensively considering the cumulative effect of ice flow velocity on bedrock stability, a denominator of 10 is set to ensure that the ice flow velocity value... 5 meters / year, monitoring duration In the case of 1 year, This is related to the density of bedrock fissures. Setting the denominator to 5 establishes a relatively reasonable weighting distribution. This allows for a balance between the effects of fracture density and ice flow velocity-time terms on bedrock stability when constructing the bedrock stability index formula.

[0077] Step 3: Set a bedrock stability threshold, compare the bedrock stability coefficients of multiple candidate regions with the bedrock stability threshold, and select candidate regions that meet the requirements.

[0078] Step 301: Set the bedrock stability threshold.

[0079] It should be noted that the bedrock stability threshold can be determined by collecting geological survey data from a large number of areas with known bedrock stability, including parameters such as bedrock fracture density and ice flow velocity. Simultaneously, it's necessary to record whether these areas have experienced past geological disasters such as bedrock collapses or landslides. Through statistical analysis, a bedrock stability index threshold can be determined, such that areas below this threshold have a higher probability of experiencing geological disasters, while areas above this threshold are relatively stable. Specifically, this can be achieved by collecting data from multiple polar calibration points or areas with similar geological conditions. and Data, along with historical geological hazard records and engineering applications in these areas, is collected. A bedrock stability index is calculated for each area, and then statistical analysis methods, such as probability distribution analysis and regression analysis, are used to determine the thresholds corresponding to a stable state. For example, logistic regression analysis is used, with the occurrence of a geological hazard as the dependent variable, where 1 represents occurrence and 0 represents non-occurrence. Using this as the independent variable, a regression model is established, and a value is determined through the model. The critical value is such that above this critical value, the probability of geological disasters occurring is less than 5%, and this critical value is used as the bedrock stability threshold.

[0080] Step 302: Compare the bedrock stability coefficients of multiple candidate regions with the bedrock stability threshold. When the bedrock stability coefficient... When the bedrock stability coefficient is ≥ the bedrock stability threshold, the corresponding candidate region meets the requirements; when the bedrock stability coefficient is ≥ the bedrock stability threshold, the corresponding candidate region meets the requirements. If the value is less than the bedrock stability threshold, then the corresponding candidate region does not meet the requirements.

[0081] Step 303: When multiple candidate regions meet the requirements, the bedrock stability coefficients of the multiple candidate regions are calculated. Compare and select the bedrock stability coefficient The candidate region corresponding to the maximum value is used as the target point for site selection.

[0082] Step 4: Construct a gravity standard platform at the selected target site and install gravity measurement equipment and outdoor safety system.

[0083] It should be noted that the gravity standard platform was constructed using techniques known in the art; the gravity measuring equipment is known in the art and installed using known installation methods. The outdoor support system uses known support devices and is installed at the selected target point using known installation methods to ensure the normal operation of the gravity measuring equipment.

[0084] It should be noted that the outdoor protection system mainly consists of an outdoor insulated tent, an electric heating device, a temperature control box, a power supply, and cables.

[0085] Step 5: Collect operational data from the gravity measurement equipment and outdoor support system using data acquisition devices, and calculate the equipment's reliability based on the operational data. And based on the equipment's reliability Determine whether the equipment status meets the standards.

[0086] It should be noted that the reliability of computing equipment is guaranteed. During the process, all parameters involved in each calculation step need to be normalized and preprocessed to eliminate the dimensions of different parameters, so as to facilitate subsequent formula calculations.

[0087] The operational data should include at least the actual operating parameter values ​​of the gravity measuring equipment. And actual environmental parameter values; actual operating parameter values At least the operating voltage of the gravity measuring equipment, the operating temperature of the equipment components, and the power frequency of the power supply device in the outdoor support system are included. The actual environmental parameter values ​​include the ambient temperature and ambient air pressure of the environment where the gravity measuring equipment is located.

[0088] Step 501: Measure the operating voltage of the gravity measuring device by connecting a digital voltmeter to the device's power output port.

[0089] Step 502: By installing multiple thermocouple temperature sensors in the concentrated area of ​​electronic components inside the equipment, temperature data is collected as the operating temperature of the equipment components.

[0090] Step 503: Connect a frequency meter to the power supply output of the device, measure the power frequency value and record it as the power frequency.

[0091] Subsidy 504: By installing barometric pressure sensors and negative temperature sensors inside the protective housing of the outdoor protection system, the ambient temperature and air pressure of the area where the gravity measurement equipment is located are collected, and the standard deviation of temperature fluctuation is calculated based on the ambient temperature. .

[0092] Step 505: Ensure reliability by running data calculation equipment The formula used is as follows:

[0093] .

[0094] in, The first of the gravity measuring devices Actual operating parameter values; The first of the gravity measuring devices The parameter settings can be obtained by consulting the equipment specifications and operation manual. The first of the gravity measuring devices The allowed fluctuation range for this parameter; among which, The serial number represents the parameter of the gravity measuring equipment, and its value is a positive integer. This refers to the number of types of equipment parameters; the value can be 1-4, representing operating voltage, operating temperature of equipment components, power supply frequency, and ambient air pressure, respectively. It is the base of the natural logarithm. The standard deviation of temperature fluctuation in the area where the gravity measuring equipment is located; This represents the threshold value for the standard deviation of temperature fluctuation in the area where the gravity measuring device is located.

[0095] It should be noted that the linear term in the formula The stability of equipment parameters is assessed. Specifically, for each equipment parameter, the proportion of its actual value deviating from the set value to the allowable fluctuation range is calculated. This proportion is then subtracted from 1 to obtain the parameter's stability contribution. The average stability contribution of all parameters is then calculated. The logic behind this calculation is that the closer the actual value of a equipment parameter is to the set value, and the smaller the fluctuation range, the higher the equipment's stability. Through equipment parameter stability assessment techniques, the operating status of equipment can be comprehensively and in real-time monitored, and potential problems during operation can be detected promptly. This is achieved using the exponential term in the formula. Assessing the impact of ambient temperature fluctuations on equipment operational stability reveals that the exponential function's properties mean that the contribution of temperature fluctuations to equipment stability decreases rapidly when the standard deviation exceeds a threshold, highlighting the significant impact of temperature fluctuations on equipment stability. Temperature fluctuation impact assessment quantifies the effect of temperature fluctuations on equipment stability, prompting operators to pay attention to and optimize the equipment's operating environment.

[0096] Step 506: Set the equipment assurance reliability threshold and set the equipment assurance reliability... Compared with the equipment assurance reliability threshold, when the equipment assurance reliability... If the equipment status is ≥ the equipment reliability threshold, then the equipment status is considered to meet the standard.

[0097] It should be noted that the equipment reliability threshold can be determined by collecting historical data of the equipment under different operating conditions, including the actual values ​​of the equipment parameters. ), set value ( ), allowable fluctuation range ( ) and the standard deviation of temperature fluctuation ( Simultaneously, the operating status of the equipment under these conditions is recorded, such as whether a fault or performance degradation occurs, and the equipment reliability is calculated for each condition. , calculate Compare and analyze the values ​​with the actual operating conditions of the equipment, and statistically analyze the values ​​during periods of trouble-free or high-performance operation. Value distribution, determine a reasonable threshold, for example, to ensure that 90% of the data points operate stably. The value is higher than this threshold. Alternatively, refer to the relevant technical specifications of the equipment manufacturer to ensure that the threshold meets the equipment design and operational requirements.

[0098] Step Six: Once the equipment meets the standards, collect gravity measurement data from the gravity measuring equipment and calculate the gravity data quality factor based on the gravity measurement data. And based on gravity data quality factor Determine whether the data collected by the gravity measuring equipment meets the requirements.

[0099] It should be noted that in calculating the quality factor of gravity data... During the process, all parameters involved in each calculation step need to be normalized and preprocessed to eliminate the dimensions of different parameters, so as to facilitate subsequent formula calculations.

[0100] Gravity measurement data includes gravity value error. and vacuum deviation .

[0101] Step 601: During the measurement process of the gravity measuring equipment, the gravitational acceleration value of each fall is recorded by the sensor and data acquisition system, and the standard gravitational acceleration value of this location is obtained. This value can be obtained from a known gravity standard point. The absolute value of the result obtained by subtracting the gravitational acceleration value obtained from each measurement from the standard gravitational acceleration value is used as the gravity value error. .

[0102] It should be noted that when there is no known gravity standard point, gravity measurement equipment can be used to continuously measure the gravity standard platform for 12 hours, and then the average value of the gravitational acceleration measured during this period can be taken as the standard gravitational acceleration value.

[0103] Step 602: A vacuum gauge installed inside the vacuum chamber of the gravity measuring device monitors the actual vacuum level in real time during the measurement process. The actual vacuum level value is subtracted from the standard vacuum level value, and the absolute value of the result is taken as the vacuum level deviation. The standard vacuum value can be determined based on the design requirements of the absolute gravimeter and the equipment technical specifications.

[0104] Step 603: Calculate the gravity data quality factor using gravity measurement data. The formula used is as follows:

[0105] .

[0106] in, Indicates the first step in the measurement process Error in the gravity value measured in this instance; This represents the maximum permissible dispersion of gravitational acceleration; Indicates the first step in the measurement process Vacuum deviation in this measurement; Indicates the standard vacuum level value; This represents the sequence number of measurements during the measurement process, and its value is a positive integer. Indicates the maximum number of measurements.

[0107] It should be noted that the exponent term in the formula Using a Gaussian function, the impact of gravity error on data quality is quantified as a value between 0 and 1. The smaller the error, the larger the exponent, indicating higher data quality. Vacuum deviation is also considered. The effect on gravity measurement, compared with the standard vacuum value. In comparison, through linear relationships The impact of vacuum deviation on data quality was assessed. A smaller vacuum deviation results in a ratio closer to 1, indicating a lower degree of influence of vacuum on data quality; conversely, a larger vacuum deviation results in a smaller ratio, indicating a worse data quality assessment. Finally, the average of multiple measurements was taken as the final value. This is to reduce the impact of random errors and comprehensively evaluate data quality.

[0108] Step 604: Set the gravity data quality threshold and adjust the gravity data quality factor. Compared with the gravity data quality threshold, when the gravity data quality factor When the data quality threshold is ≥, the data collected by the gravity measuring device is deemed to meet the requirements.

[0109] It should be noted that the gravity data quality threshold can be determined by collecting a large number of known high-quality and low-quality gravity data samples. High-quality data samples refer to data collected under favorable conditions using high-precision instruments, and which have undergone rigorous quality control and verification. Low-quality data samples refer to data with significant errors or interference. The quality threshold is calculated separately for each of these samples. Value. For example, if 1000 sets of high-quality data and 1000 sets of low-quality data are collected, calculate the value for each set of data. Value; Analysis of high-quality and low-quality data Value distribution. For example, statistical analysis reveals that high-quality data... 90% of the values ​​are concentrated above 0.8. A reasonable threshold should be determined based on this distribution. For example, setting the threshold to 0.7 can ensure that most of the data is of high quality. The value is above the threshold, while most of the data is of low quality. The value is below the threshold. This threshold can be adjusted appropriately according to the specific requirements of the application. For example, if extremely high data quality is required, the threshold can be increased to 0.85. At the same time, the determined threshold needs to be verified, which can be done by using newly collected gravity data... The value is compared with this threshold to verify the accuracy of its judgment on data quality. For example, in practical applications, for 200 newly collected data sets (of which 100 sets are known to be high quality and 100 sets to be low quality), the following calculations are performed. The values ​​are analyzed, and their compliance with the threshold is statistically evaluated. The compliance rate is used to verify the reasonableness of the threshold. If the compliance rate is low (e.g., below 80%), the threshold needs to be readjusted.

[0110] Step 7: When the collected data meets the requirements, acquire the interference data, and through the interference data analysis model, obtain the solid tide correction residual value, the uncorrected amount of ice sheet mass change, and the pressure disturbance correction residual value, and further calculate the total environmental factor correction value. Interference suppression coefficient and equipment calibration correction items The gravitational acceleration calibration value was calculated based on the above parameters. .

[0111] It should be noted that when calculating the calibration value of gravitational acceleration... During the process, all parameters involved in each calculation step need to be normalized and preprocessed to eliminate the dimensions of different parameters, so as to facilitate subsequent formula calculations.

[0112] Interference data includes solid tide interference data, ice sheet mass interference data, air pressure disturbance data, and equipment interference data.

[0113] Step 701: Acquire solid tide interference data, including the latitude, longitude, elevation, and corresponding measurement time data of the selected target point; input the above data into solid tide modeling software, such as the tide software provided by IERS, to calculate the solid tide correction value for this location and time. Subtract the actual measured gravitational acceleration value from the correction value calculated by the model to obtain the solid tide correction residual value. .

[0114] Step 702: Obtain ice sheet mass disturbance data, such as information on ice sheet mass changes in the measurement area from GRACE satellite data. This data is typically provided in grid form, representing the mass change per unit area. Input this data into a gravity effect calculation model, such as the STIM satellite gravity measurement model, to obtain the change in gravitational acceleration. Subtracting the change in gravitational acceleration from the measured value of gravitational acceleration yields the uncorrected amount. .

[0115] Step 703: Acquiring air pressure disturbance data includes collecting air pressure change data by installing air pressure sensors at the measurement location, and inputting the air pressure change data into an air pressure-gravity relationship model, such as an air load model, to calculate the theoretical value of the change in gravitational acceleration caused by air pressure changes. The actual measured value of gravitational acceleration is subtracted from the theoretical value of the change in gravitational acceleration to obtain the residual value of the pressure disturbance correction. .

[0116] It should be noted that the solid tide model software, the gravity effect calculation model, and the pressure-gravity relationship model can all use calculation models known in the field.

[0117] Step 704: Correct the solid moisture residual value Uncorrected amount and pressure disturbance correction residuals Summation calculation yields the total environmental factor correction value. .

[0118] Step 705: Correcting residuals based on solid tides Uncorrected amount and pressure disturbance correction residuals Calculate the interference suppression coefficient The formula used is as follows:

[0119] .

[0120] It should be noted that the formula first corrects the residual value for solid moisture. Uncorrected amount and pressure disturbance correction residuals Each value is normalized to its respective theoretical change value to form a dimensionless ratio. This step eliminates the influence of different units and dimensions, facilitating comprehensive evaluation. Then, the formula takes the square root of the sum of the squares of these normalized values ​​and uses the Euclidean norm method to measure the vector length in multidimensional space, thereby comprehensively evaluating the interference intensity of multiple environmental factors. Finally, the formula calculates the ratio by subtracting the normalized value from 1. This design makes The closer the value is to 1, the better the suppression effect of environmental interference.

[0121] Step 706: Obtain the equipment calibration parameters from the absolute gravimeter's calibration certificate, including the zero-point drift value Z and the linear drift value L. Calculate the zero-point drift correction term Zcorrection based on the zero-point drift value Z, where Zcorrection = Z. Calculate the linear drift coefficient Lcorrection based on the linear drift value L, using the formula: Lcorrection = L * t, where t is the measurement time interval. Finally, sum the zero-point drift correction term Zcorrection and the linear drift coefficient Lcorrection to obtain the equipment calibration correction term. .

[0122] Step 707: Calculate the average value of the gravitational acceleration values ​​obtained from multiple actual measurements to obtain the initial measurement value. .

[0123] Step 708: Adjust based on total environmental factors Interference suppression coefficient Equipment calibration correction items and initial measurement value Calculate the calibration value of gravitational acceleration The formula used is:

[0124] .

[0125] It should be noted that the total environmental factors correction item This represents the total impact of environmental factors on gravitational acceleration, but directly using... The actual impact may be overestimated or underestimated because environmental disturbances are often impossible to measure and correct for completely accurately in actual measurements. This reflects the mitigating effect of the corrective measures on environmental disturbances. Multiplying the two means dynamically adjusting the total environmental factor correction term to better reflect the actual residual disturbance level after correction. For example, if A lower value (close to 0) indicates a poor correction effect; after multiplication... A smaller adjustment for environmental factors means that the final result requires less adjustment, suggesting that the initial revised model's estimation of environmental factors may be significantly biased and requires careful consideration; conversely, if... A higher value (close to 1) indicates a good correction effect; after multiplication... near The final result adequately considers the correction for environmental factors. This multiplicative relationship comprehensively reflects the roles of environmental factor correction and correction effect evaluation. On the one hand, the total environmental factor correction term provides a basic quantification of the impact of environmental factors; on the other hand, the interference suppression coefficient evaluates the actual effect of these correction measures. Multiplying the two not only corrects the initial measurement value but also adjusts the magnitude of the correction based on the correction effect, making the final result more scientific and reasonable, taking into account both the impact of environmental factors and the reliability of the correction measures.

[0126] When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0127] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0128] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for calibrating absolute gravitational acceleration, characterized in that, include: Step 1: By collecting geological structure data, topographic data, and meteorological data of the polar regions, several candidate areas are initially identified within the existing station areas; Step 2: Collect bedrock stability data for candidate areas and calculate the bedrock stability coefficient for each candidate area. ; Step 3: Set a bedrock stability threshold and compare the bedrock stability coefficients of multiple candidate regions. The regions were compared with the bedrock stability threshold to select candidate regions that met the requirements. Step 4: Construct a gravity standard platform at the selected target site and install gravity measurement equipment and outdoor safety system; Step 5: Collect operational data from the gravity measurement equipment and outdoor support system using data acquisition devices, and calculate the equipment's reliability based on the operational data. And based on the equipment's reliability Determine whether the equipment status meets the standards; Step Six: Once the equipment meets the standards, collect gravity measurement data from the gravity measuring equipment and calculate the gravity data quality factor based on the gravity measurement data. And based on gravity data quality factor Determine whether the data collected by the gravity measuring equipment meets the requirements; Step 7: When the collected data meets the requirements, acquire the interference data, and through the interference data analysis model, obtain the solid tide correction residual value, the uncorrected amount of ice sheet mass change, and the pressure disturbance correction residual value, and further calculate the total environmental factor correction value. Interference suppression coefficient and equipment calibration correction items And based on the total environmental factors correction value Interference suppression coefficient Equipment calibration correction items and initial measurement value The calculated calibration value of gravitational acceleration is obtained. .

2. The absolute gravitational acceleration calibration method according to claim 1, characterized in that, In step one: the bedrock area surrounding the station area is selected based on geological structural data, which is used as the first selection criterion; Based on topographic data, areas with a vertical elevation difference greater than 10m from the standard points of the original surveying and mapping bureau were selected as the second screening criterion. Based on meteorological data, areas with wind force levels less than level 8 were selected as the third screening criterion. Regions that simultaneously meet screening criteria one, screening criteria two, and screening criteria three are selected as candidate regions.

3. The absolute gravitational acceleration calibration method according to claim 2, characterized in that, Bedrock stability data includes bedrock fracture density. and ice flow rate value Specifically: Within the selected candidate area, several observation plots of unit area are delineated. Measuring tools are used to measure bedrock fissures within the plots. The bedrock fissure density is calculated by counting the number of fissures within each plot and dividing by the plot area. ; Global Positioning System (GPS) monitoring points are installed on the surface of ice bodies in polar regions to record the position coordinates of the ice bodies at different times. The displacement distance of the ice bodies between two time points is calculated and divided by the time interval to obtain the ice flow velocity. The average of the acquired ice flow velocities is then calculated as the ice flow velocity value for the measurement cycle. .

4. The absolute gravitational acceleration calibration method according to claim 3, characterized in that, Based on bedrock fracture density and ice flow rate value Calculate the bedrock stability index The formula used is as follows: ； Where e is the base of the natural logarithm, The duration of the ice flow rate detection.

5. The absolute gravitational acceleration calibration method according to claim 4, characterized in that, The bedrock stability coefficients of multiple candidate regions were compared with the bedrock stability threshold. When the bedrock stability coefficient is ≥ the bedrock stability threshold, the corresponding candidate region meets the requirements; when the bedrock stability coefficient is ≥ the bedrock stability threshold, the corresponding candidate region meets the requirements. If the value is less than the bedrock stability threshold, then the corresponding candidate region does not meet the requirements; When multiple candidate regions meet the requirements, the bedrock stability coefficients of these candidate regions are... Compare and select the bedrock stability coefficient The candidate region corresponding to the maximum value is used as the target point for site selection.

6. The absolute gravitational acceleration calibration method according to claim 5, characterized in that, The operational data should include at least the actual operating parameter values ​​of the gravity measuring equipment. And actual environmental parameter values; actual operating parameter values At least the operating voltage of the gravity measuring equipment, the operating temperature of the equipment components, and the power frequency of the power supply device in the outdoor support system are included. The actual environmental parameter values ​​include the ambient temperature and ambient air pressure of the environment where the gravity measuring equipment is located.

7. The absolute gravitational acceleration calibration method according to claim 6, characterized in that, Reliability is ensured by operating data computing equipment. The formula used is as follows: ； in, The first of the gravity measuring devices Actual operating parameter values; The first of the gravity measuring devices Parameter setting value; The first of the gravity measuring devices The allowed fluctuation range for this parameter; among which, The serial number represents the parameter of the gravity measuring equipment, and its value is a positive integer. This refers to the number of types of equipment parameters; It is the base of the natural logarithm. The standard deviation of temperature fluctuation in the area where the gravity measuring equipment is located; The threshold value representing the standard deviation of temperature fluctuation in the area where the gravity measuring equipment is located; Ensure equipment reliability Compared with the equipment assurance reliability threshold, when the equipment assurance reliability... If the equipment status is ≥ the equipment reliability threshold, then the equipment status is considered to meet the standard.

8. The absolute gravitational acceleration calibration method according to claim 7, characterized in that, Gravity measurement data includes gravity value error. and vacuum deviation ; The gravity data quality factor is calculated using gravity measurement data. The formula used is as follows: ； in, Indicates the first step in the measurement process Error in the gravity value measured in this instance; This represents the maximum permissible dispersion of gravitational acceleration; Indicates the first step in the measurement process Vacuum deviation in this measurement; Indicates the standard vacuum level value; This represents the sequence number of measurements during the measurement process, and its value is a positive integer. Indicates the maximum number of measurements; Gravity data quality factor Compared with the gravity data quality threshold, when the gravity data quality factor When the data quality threshold is ≥, the data collected by the gravity measuring device is deemed to meet the requirements.

9. The absolute gravitational acceleration calibration method according to claim 8, characterized in that, Interference data includes solid tide interference data, ice sheet mass interference data, air pressure disturbance data, and equipment interference data; Input solid tide interference data into solid tide modeling software to calculate solid tide correction values. The actual measured gravitational acceleration value is compared with the solid tide correction value calculated by the model. Subtracting the two yields the solid moisture correction residual. ; The ice sheet mass disturbance data is input into the gravity effect calculation model to obtain the change value of gravitational acceleration. Subtracting the change in gravitational acceleration from the measured value of gravitational acceleration yields the uncorrected amount. ; Input the air pressure disturbance data into the air pressure-gravity relationship model to calculate the theoretical value of the change in gravitational acceleration caused by the change in air pressure. The actual measured value of gravitational acceleration is subtracted from the theoretical value of the change in gravitational acceleration to obtain the residual value of the pressure disturbance correction. ; The equipment interference data includes zero drift value Z and linear drift value L. The zero drift correction term Zcorrection is obtained based on the zero drift value Z, and Zcorrection = Z. The linear drift coefficient Lcorrection is calculated based on the linear drift value L using the formula: Lcorrection = L * t, where t is the measurement time interval. The zero-point drift correction term Zcorrection and the linear drift coefficient Lcorrection are then summed to obtain the equipment calibration correction term. .

10. The absolute gravitational acceleration calibration method according to claim 9, characterized in that, Correcting the residual value of solid tide Uncorrected amount and pressure disturbance correction residuals Summation calculation yields the total environmental factor correction value. ; Based on solid tide correction residuals Uncorrected amount and pressure disturbance correction residuals Calculate the interference suppression coefficient The formula used is as follows: ； The initial measurement value is obtained by averaging the gravitational acceleration values ​​obtained from multiple actual measurements. ; Based on the total environmental factors correction value Interference suppression coefficient Equipment calibration correction items and initial measurement value Calculate the calibration value of gravitational acceleration The formula used is: 。

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