A method and system for processing measurement data of a small platform gravimeter

Abstract

The present invention relates to the field of gravity measurement technology, and specifically discloses a method and system for processing measurement data of a small platform gravimeter, the method comprising: obtaining GNSS navigation data and gravimeter inertial measurement data; calculating gravity anomaly values ​​and vertical acceleration; respectively calculating the amplitude coherence function of the vertical acceleration and its square with the gravity anomaly value, taking the frequency points with the coherence function value greater than a threshold, obtaining a first frequency point set and a second frequency point set; setting the values ​​corresponding to the first frequency point set and the second frequency point set in the gravity anomaly frequency domain information to zero, and obtaining time domain gravity anomaly information with linear and nonlinear residual errors eliminated by inverse fast Fourier transform. The present invention can eliminate the linear and nonlinear coupling errors of motion acceleration remaining in conventional data processing of the gravimeter, realize high-precision extraction of gravity anomaly signals under small carrier and high dynamic conditions, and improve the dynamic environmental adaptability and measurement accuracy of the gravimeter.

Description

Technical Field

[0001] The present invention relates to the field of gravity measurement technology, and in particular to a method and system for processing measurement data of a small platform gravimeter. Background Art

[0002] The main measurement part of the gravimeter includes an inertial measurement unit and an inertial stabilization platform. The inertial measurement unit includes three single-axis fiber optic gyroscopes, two horizontal accelerometers and a vertical gravity sensor. Among them, the gravity sensor is also used as a vertical accelerometer. In order to adapt to the stringent requirements of small carriers such as unmanned boats, AUVs, and drones on the size and weight of instruments, the gravimeter does not adopt a three-ring inertial platform solution, but instead uses a more compact azimuth strapdown inertial platform solution. In terms of structural configuration, the gravimeter platform consists of two horizontal universal ring frames. There is no universal ring frame structure in azimuth. The inertial measurement unit is built into the two horizontal universal ring frames, thus forming an azimuth strapdown inertial platform. The mechanical part of the platform consists of a base, an outer frame and an inner frame. The outer frame is a pitch ring, the inner frame is a roll ring, and three gyroscopes and three accelerometers (gravity sensors) are orthogonally installed on the inner frame. Functionally, the platform's horizontal ring stabilization loop uses fiber optic gyro-based stabilization loop technology to achieve inertial system stabilization of the two horizontal degrees of freedom and isolate the horizontal angular motion of the carrier. The correction loop uses the results of the navigation solution to control the azimuth strapdown platform to track the local geographic level, so that the input axis of the gravity sensor is strictly parallel to the geographic vertical direction, and completes the direct measurement of vertical acceleration, that is, the measurement of raw gravity information. In the later stage of gravity data processing, the original gravity measurement values ​​are processed by Ertfos correction, normal gravity correction, zero drift correction, data filtering, etc. with the help of reference information such as GNSS satellite navigation information, and finally the free space gravity anomaly information is obtained.

[0003] During the movement of the carrier, the azimuth strapdown inertial platform dynamically tracks the local geographic level in real time, and the gravity sensor directly measures the original gravity information. In theory, during the data processing stage, the gravity anomaly signal can be extracted by performing standard error correction and data filtering on the original gravity measurement values. However, small platform gravimeters are usually installed on unmanned platforms such as unmanned boats, AUVs, and drones. Since such platforms are small in size, light in weight, and susceptible to interference from waves and gusts, they are often in a large amplitude heave motion condition in the vertical direction, resulting in a significant increase in the vertical motion acceleration excitation compared to shipborne gravity measurements.

[0004] Since the calibration value of the gravity sensor scale factor cannot be ideal and error-free, and the gravity sensor itself has nonlinear characteristics, the gravity measurement data of the unmanned platform is easily contaminated by motion acceleration excitation, which puts very high demands on the gravimeter error correction and data filtering.

[0005] Actual experimental tests show that the error correction and data filtering schemes of conventional platform gravimeters cannot completely eliminate the linear and nonlinear residual errors related to motion acceleration, and the accuracy of gravity measurement under this condition will be significantly reduced. There is currently no effective solution and related research results for this problem. Therefore, it is urgent to study more advanced gravity measurement data processing methods to eliminate the linear and nonlinear residual errors related to motion acceleration in the output data of gravity sensors. Summary of the invention

[0006] The present invention aims to solve the problem that the small platform gravimeter is often in a large amplitude heave motion condition in the vertical direction, has large linear and nonlinear residual errors related to motion acceleration, and has low gravity measurement accuracy. To this end, the present invention provides a method and system for processing measurement data of a small platform gravimeter, which can eliminate the linear and nonlinear coupling errors of motion acceleration residual in conventional data processing of the gravimeter, realize high-precision extraction of gravity anomaly signals under small carrier and high dynamic conditions, and improve the dynamic environmental adaptability and measurement accuracy of the gravimeter.

[0007] The present invention provides a method for processing measurement data of a small platform gravimeter, and the technical solution adopted is as follows:

[0008] Obtain GNSS navigation data and gravimeter inertial measurement data;

[0009] The gravity anomaly value is calculated based on the GNSS navigation data and the gravimeter inertial measurement data;

[0010] According to the GNSS navigation data, the vertical acceleration is calculated;

[0011] Calculating the amplitude coherence function of the vertical acceleration and gravity anomaly value, taking the frequency points where the coherence function value is greater than a threshold, and obtaining a first frequency point set;

[0012] Calculating the amplitude coherence function of the square of the vertical acceleration and the gravity anomaly value, taking the frequency points where the coherence function value is greater than a threshold, and obtaining a second frequency point set;

[0013] Performing a fast Fourier transform on the gravity anomaly value to calculate the gravity anomaly frequency domain information; setting the values ​​corresponding to the first frequency point set and the second frequency point set in the gravity anomaly frequency domain information to zero, and then performing an inverse fast Fourier transform to calculate the time domain gravity anomaly information with linear and nonlinear residual errors eliminated.

[0014] Furthermore, the target frequency interval of the amplitude coherence function is 0.001 Hz to 1 Hz.

[0015] Furthermore, the threshold is 0.8.

[0016] Furthermore, the frequency range of the gravity anomaly frequency domain information is 0 to 1 Hz.

[0017] Furthermore, according to the GNSS navigation data, the process of calculating the vertical acceleration is: performing differential processing on the vertical velocity in the GNSS navigation data to obtain the vertical acceleration.

[0018] Furthermore, based on the GNSS navigation data and the gravimeter inertial measurement data, the process of calculating the gravity anomaly value is as follows:

[0019] Based on the longitude, latitude, altitude, easting speed, northing speed and vertical speed in the GNSS navigation data, the Eötvös correction value, the normal gravity correction value, the horizontal acceleration correction value and the vertical acceleration correction value at each sampling time are calculated; and then the FIR low-pass filter is used to filter them respectively to obtain the filtered value of the Eötvös correction value, the filtered value of the normal gravity correction value, the filtered value of the horizontal acceleration correction value and the filtered value of the vertical acceleration correction value;

[0020] The east specific force, north specific force and vertical specific force in the inertial measurement data of the gravimeter are extracted respectively, and the sampling rate thereof is adjusted to be the same as the sampling rate of the GNSS navigation data; and then the FIR low-pass filter is used to filter them respectively to obtain the filtered value of the east specific force, the filtered value of the north specific force and the filtered value of the vertical specific force;

[0021] The gravity anomaly value at each sampling moment is calculated based on the filtered value of the east specific force, the filtered value of the north specific force and the filtered value of the vertical specific force, as well as the filtered value of the Eertfus correction value, the filtered value of the normal gravity correction value, the filtered value of the horizontal acceleration correction value and the filtered value of the vertical acceleration correction value.

[0022] The present invention also provides a small platform gravimeter measurement data processing system, the technical solution adopted is as follows:

[0023] A data acquisition unit, a data calculation unit, a frequency calculation unit and a gravity anomaly calculation unit, wherein the data acquisition unit is connected to the data calculation unit, the data calculation unit is respectively connected to the frequency calculation unit and the gravity anomaly calculation unit, and the frequency calculation unit is connected to the gravity anomaly calculation unit.

[0024] Data acquisition unit, used to obtain GNSS navigation data and gravimeter inertial measurement data;

[0025] A data calculation unit is used to calculate the gravity anomaly value according to the GNSS navigation data and the gravimeter inertial measurement data; and to calculate the vertical acceleration according to the GNSS navigation data;

[0026] A frequency point calculation unit is used to calculate the amplitude coherence function of the vertical acceleration and the gravity anomaly value, take the frequency point whose coherence function value is greater than the threshold, and obtain a first frequency point set; calculate the amplitude coherence function of the square of the vertical acceleration and the gravity anomaly value, take the frequency point whose coherence function value is greater than the threshold, and obtain a second frequency point set;

[0027] The gravity anomaly calculation unit is used to perform a fast Fourier transform on the gravity anomaly value to calculate the gravity anomaly frequency domain information; set the values ​​corresponding to the first frequency point set and the second frequency point set in the gravity anomaly frequency domain information to zero, and then perform an inverse fast Fourier transform to calculate the time domain gravity anomaly information with linear and nonlinear residual errors eliminated.

[0028] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0029] The present invention locates the frequency points with strong correlation between the vertical acceleration of the carrier and the gravity anomaly through amplitude coherence function analysis, and completely eliminates the linear and nonlinear residual errors related to the motion acceleration from the frequency domain by setting the values ​​of the frequency points corresponding to the gravity anomaly frequency domain information to "0", thereby solving the problem of residual errors related to the vertical motion acceleration of the carrier in the gravity anomaly information obtained by the existing conventional gravity measurement data processing method, and ensuring the gravity measurement accuracy under small carriers and high dynamic conditions.

[0030] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 It is a flow chart of the method provided by the present invention.

[0033] Figure 2 It is a comparison diagram of gravity anomalies of the survey lines of the traditional method provided by the present invention and the present method.

[0034] Figure 3 It is a structural block diagram of the system provided by the present invention.

[0035] Reference numerals:

[0036] 1. Data acquisition unit; 2. Data calculation unit; 3. Frequency calculation unit; 4. Gravity anomaly calculation unit. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0038] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0039] Small platform gravimeters are usually installed on unmanned platforms such as unmanned boats, AUVs, and drones. Since these platforms are small in size, light in weight, and easily affected by waves and gusts, they are often in a large amplitude heave motion condition in the vertical direction, resulting in a significant increase in vertical motion acceleration excitation compared to shipborne gravity measurements. Conventional platform gravimeter error correction and data filtering schemes cannot completely eliminate linear and nonlinear residual errors related to motion acceleration.

[0040] The gravity field is the basic physical field of the earth. The gravity anomaly is caused by the uneven density distribution of the earth's internal materials. Theoretically, the gravity anomaly information measured by the gravimeter is independent of the carrier's motion acceleration, and there should be no correlation between the two. Based on the above mechanism, the present invention analyzes the frequency points with strong correlation between the vertical motion acceleration of the positioning carrier and the gravity anomaly through the amplitude coherence function, and by setting the spectrum value of the frequency point corresponding to the gravity anomaly to "0", the influence of linear and nonlinear residual errors related to motion acceleration is completely eliminated from the frequency domain, ensuring the accuracy of gravity measurement under small carrier and high dynamic conditions.

[0041] Combine the following Figures 1 to 3 The present invention is further described in detail, and a method and system for processing measurement data of a small platform gravimeter of the present invention are described as follows:

[0042] In this embodiment, Figure 1 As shown, a method for processing measurement data of a small platform gravimeter is provided, comprising the following steps:

[0043] Step 1: Obtain GNSS navigation data and gravimeter inertial measurement data.

[0044] During the gravity measurement phase of the unmanned platform, the GNSS navigation data output by the GNSS satellite navigation system is obtained. The GNSS navigation data includes longitude, latitude, altitude, eastward speed, northward speed and vertical speed, and the sampling rate is 2Hz. At the same time, the gravimeter inertial measurement data output by the gravimeter inertial measurement unit is obtained. The gravimeter inertial measurement data includes eastward specific force, northward specific force and vertical specific force, and the sampling rate is 100Hz. The GNSS navigation data and the gravimeter inertial measurement data are obtained synchronously. Generally, the synchronization error is no more than 10ms.

[0045] Step 2: Calculate the gravity anomaly value based on the GNSS navigation data and the gravimeter inertial measurement data.

[0046] Specifically, based on the longitude, latitude, altitude, easting speed, northing speed and vertical speed in the GNSS navigation data, the Eötvös correction value, the normal gravity correction value, the horizontal acceleration correction value and the vertical acceleration correction value at each sampling time are calculated; and then a FIR low-pass filter is used to filter them respectively to obtain the filtered value of the Eötvös correction value, the filtered value of the normal gravity correction value, the filtered value of the horizontal acceleration correction value and the filtered value of the vertical acceleration correction value;

[0047] The east specific force, north specific force and vertical specific force in the inertial measurement data of the gravimeter are extracted respectively, and the sampling rates thereof are adjusted to be the same as the sampling rate of the GNSS navigation data, that is, the sampling rates of the east specific force, the north specific force and the vertical specific force are adjusted to 2 Hz; and then the FIR low-pass filter is used to filter them respectively to obtain the filtered values ​​of the east specific force, the north specific force and the vertical specific force;

[0048] The gravity anomaly value at each sampling time is calculated based on the filtered values ​​of the east specific force, the north specific force and the vertical specific force, as well as the filtered values ​​of the Eertvous correction value, the normal gravity correction value, the horizontal acceleration correction value and the vertical acceleration correction value. .

[0049] The specific calculation process of gravity anomaly values ​​can be referred to "Theoretical Methods and Applications of Airborne Gravity Exploration" compiled by Xiong Shengqing et al. and published by Geological Publishing House in 2010.

[0050] The cutoff frequency of the FIR low-pass filter is related to the carrier speed and spatial resolution, and the calculation formula is:

[0051]

[0052] in, Indicates the cutoff frequency, in Hz; Indicates the carrier speed, in m / s; Indicates the spatial resolution, in meters.

[0053] Step 3: Calculate the vertical acceleration based on the GNSS navigation data.

[0054] Specifically, the vertical velocity in the GNSS navigation data is differentially processed to obtain the vertical acceleration In order to ensure the accuracy of the acceleration information in the frequency band above 0.1 Hz after differentiation, a Newton-Coates differentiator is used to calculate the vertical acceleration.

[0055] Step 4: Calculate the amplitude coherence function of the vertical acceleration and gravity anomaly value, take the frequency points where the coherence function value is greater than the threshold, and obtain the first frequency point set.

[0056] Specifically, the vertical acceleration is calculated in the gravity information sensitive frequency band of the target frequency range 0.001Hz to 1Hz. and gravity outliers Amplitude coherence function , the calculation formula is:

[0057]

[0058] in, express The autopower spectrum of ; Indicated Autopower spectrum, units ; express and The cross power spectrum, in units ; Indicates the signal frequency, unit Hz, .

[0059] Record The frequency points whose coherence function value is greater than 0.8 in the first frequency point set are obtained. The threshold value of 0.8 is an empirical value obtained through processing a large amount of measured data.

[0060] Step 5: Calculate the amplitude coherence function of the square of the vertical acceleration and the gravity anomaly value, take the frequency points where the coherence function value is greater than the threshold, and obtain the second frequency point set.

[0061] Specifically, first, the vertical acceleration Take the square and calculate the square of the vertical acceleration , then calculate the square of the vertical acceleration within the target frequency range of 0.001Hz to 1Hz and gravity outliers Amplitude coherence function , the calculation formula is:

[0062]

[0063] in, express The autopower spectrum of ; express and The cross power spectrum, in units .

[0064] Last Record The frequency points whose coherence function value is greater than 0.8 in the second frequency point set are obtained. .

[0065] Step 6: Perform a fast Fourier transform on the gravity anomaly value to calculate the gravity anomaly frequency domain information; set the values ​​corresponding to the first frequency point set and the second frequency point set in the gravity anomaly frequency domain information to zero, and then perform an inverse fast Fourier transform to calculate the time domain gravity anomaly information with linear and nonlinear residual errors eliminated.

[0066] Specifically, for gravity anomalies Perform fast Fourier transform (FFT) processing to obtain frequency domain information of gravity anomaly in the frequency range of 0 to 1 Hz , the calculation formula is:

[0067]

[0068] in, stands for Fast Fourier Transform.

[0069] Then, the frequency domain information of gravity anomaly in the frequency range of 0 to 1 Hz is Corresponding to the first frequency set and the second frequency set The amplitude at is set to zero, and the inverse fast Fourier transform (IFFT) is performed to calculate the time-domain gravity anomaly information with linear and nonlinear residual errors eliminated. .

[0070]

[0071] in, represents the inverse fast Fourier transform, Represents the frequency domain information of gravity anomaly after the amplitude is set to zero.

[0072] Taking a drone-mounted gravity measurement operation as an example, the gravity anomaly comparison chart of the survey line obtained by the traditional method and this method is as follows: Figure 2 As shown, the gravity anomaly curve obtained according to this method is smoother as a whole, indicating that the residual error related to the carrier motion in the gravity anomaly is greatly reduced and the accuracy of the gravity information is significantly improved.

[0073] In this embodiment, Figure 3 As shown, a processing system for measuring data of a small platform gravimeter is also provided, and the technical scheme adopted is as follows: comprising: a data acquisition unit 1, a data calculation unit 2, a frequency point calculation unit 3 and a gravity anomaly calculation unit 4, wherein the data acquisition unit 1 is connected to the data calculation unit 2, and the data calculation unit 2 is respectively connected to the frequency point calculation unit 3 and the gravity anomaly calculation unit 4, and the frequency point calculation unit 3 is connected to the gravity anomaly calculation unit 4.

[0074] A data acquisition unit 1, used to obtain GNSS navigation data and gravimeter inertial measurement data;

[0075] The data calculation unit 2 is used to calculate the gravity anomaly value according to the GNSS navigation data and the gravimeter inertial measurement data; and to calculate the vertical acceleration according to the GNSS navigation data;

[0076] The frequency point calculation unit 3 is used to calculate the amplitude coherence function of the vertical acceleration and the gravity anomaly value, take the frequency point whose coherence function value is greater than the threshold, and obtain the first frequency point set; calculate the amplitude coherence function of the square of the vertical acceleration and the gravity anomaly value, take the frequency point whose coherence function value is greater than the threshold, and obtain the second frequency point set;

[0077] The gravity anomaly calculation unit 4 is used to perform fast Fourier transform on the gravity anomaly value to calculate the gravity anomaly frequency domain information; set the values ​​corresponding to the first frequency point set and the second frequency point set in the gravity anomaly frequency domain information to zero, and then perform inverse fast Fourier transform to calculate the time domain gravity anomaly information with linear and nonlinear residual errors eliminated.

[0078] The data acquisition unit 1 acquires GNSS navigation data and gravimeter inertial measurement data, and then transmits the GNSS navigation data and gravimeter inertial measurement data to the data calculation unit 2 .

[0079] The data calculation unit 2 calculates the gravity anomaly value based on the GNSS navigation data and the gravimeter inertial measurement data using conventional methods, and also performs differential processing on the vertical velocity information in the GNSS navigation data to calculate the vertical acceleration; then the gravity anomaly value and the vertical acceleration are transmitted to the frequency point calculation unit 3, and the gravity anomaly value is transmitted to the gravity anomaly calculation unit 4.

[0080] The frequency point calculation unit 3 calculates the amplitude coherence function of the vertical acceleration and the gravity anomaly value, takes the frequency points whose coherence function values ​​are greater than the threshold, and obtains a first frequency point set; it also calculates the square of the vertical acceleration, and then calculates the amplitude coherence function of the square of the vertical acceleration and the gravity anomaly value, takes the frequency points whose coherence function values ​​are greater than the threshold, and obtains a second frequency point set; finally, the first frequency point set and the second frequency point set are transmitted to the gravity anomaly calculation unit 4.

[0081] The gravity anomaly calculation unit 4 first performs a fast Fourier transform on the gravity anomaly value to calculate the gravity anomaly frequency domain information; then sets the values ​​corresponding to the first frequency point set and the second frequency point set in the gravity anomaly frequency domain information to zero, and then performs an inverse fast Fourier transform to calculate the time domain gravity anomaly information with linear and nonlinear residual errors eliminated.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for processing measurement data of a small platform gravimeter, characterized in that: include: Obtain GNSS navigation data and gravimeter inertial measurement data; The gravity anomaly value is calculated based on the GNSS navigation data and the gravimeter inertial measurement data; According to the GNSS navigation data, the vertical acceleration is calculated; Calculating the amplitude coherence function of the vertical acceleration and gravity anomaly value, taking the frequency points where the coherence function value is greater than a threshold, and obtaining a first frequency point set; Calculating the amplitude coherence function of the square of the vertical acceleration and the gravity anomaly value, taking the frequency points where the coherence function value is greater than a threshold, and obtaining a second frequency point set; Performing a fast Fourier transform on the gravity anomaly value to calculate the frequency domain information of the gravity anomaly; The values ​​corresponding to the first frequency point set and the second frequency point set in the gravity anomaly frequency domain information are set to zero, and then an inverse fast Fourier transform is performed to calculate the time domain gravity anomaly information with linear and nonlinear residual errors eliminated.

2. A method for processing measurement data of a small platform gravimeter as claimed in claim 1, characterized in that: The target frequency range of the amplitude coherence function is 0.001 Hz to 1 Hz.

3. A method for processing measurement data of a small platform gravimeter as claimed in claim 1 or 2, characterized in that: The threshold is 0.

8.

4. A method for processing measurement data of a small platform gravimeter as claimed in claim 1 or 2, characterized in that: The frequency range of the gravity anomaly frequency domain information is 0 to 1 Hz.

5. The method for processing measurement data of a small platform gravimeter as claimed in claim 1, characterized in that: The process of calculating the vertical acceleration according to the GNSS navigation data is as follows: performing differential processing on the vertical velocity in the GNSS navigation data to obtain the vertical acceleration.

6. The method for processing measurement data of a small platform gravimeter according to claim 1, characterized in that: According to the GNSS navigation data and the gravimeter inertial measurement data, the process of calculating the gravity anomaly value is as follows: Based on the longitude, latitude, altitude, easting speed, northing speed and vertical speed in the GNSS navigation data, the Eötvös correction value, the normal gravity correction value, the horizontal acceleration correction value and the vertical acceleration correction value at each sampling time are calculated; and then the FIR low-pass filter is used to filter them respectively to obtain the filtered value of the Eötvös correction value, the filtered value of the normal gravity correction value, the filtered value of the horizontal acceleration correction value and the filtered value of the vertical acceleration correction value; Extracting the east specific force, north specific force and vertical specific force from the gravimeter inertial measurement data respectively, and adjusting the sampling rate thereof to be the same as the sampling rate of the GNSS navigation data; Then use FIR low-pass filter to filter respectively to obtain the filtering value of east specific force, the filtering value of north specific force and the filtering value of vertical specific force; The gravity anomaly value at each sampling moment is calculated based on the filtered value of the east specific force, the filtered value of the north specific force and the filtered value of the vertical specific force, as well as the filtered value of the Eertfus correction value, the filtered value of the normal gravity correction value, the filtered value of the horizontal acceleration correction value and the filtered value of the vertical acceleration correction value.

7. A small platform gravimeter measurement data processing system, characterized in that: A method for processing measurement data of a small platform gravimeter according to any one of claims 1 to 6, comprising: a data acquisition unit, a data calculation unit, a frequency calculation unit and a gravity anomaly calculation unit, wherein the data acquisition unit is connected to the data calculation unit, the data calculation unit is respectively connected to the frequency calculation unit and the gravity anomaly calculation unit, and the frequency calculation unit is connected to the gravity anomaly calculation unit. Data acquisition unit, used to obtain GNSS navigation data and gravimeter inertial measurement data; A data calculation unit is used to calculate the gravity anomaly value according to the GNSS navigation data and the gravimeter inertial measurement data; and to calculate the vertical acceleration according to the GNSS navigation data; A frequency point calculation unit is used to calculate the amplitude coherence function of the vertical acceleration and the gravity anomaly value, take the frequency point whose coherence function value is greater than the threshold, and obtain a first frequency point set; calculate the amplitude coherence function of the square of the vertical acceleration and the gravity anomaly value, take the frequency point whose coherence function value is greater than the threshold, and obtain a second frequency point set; The gravity anomaly calculation unit is used to perform a fast Fourier transform on the gravity anomaly value to calculate the gravity anomaly frequency domain information; set the values ​​corresponding to the first frequency point set and the second frequency point set in the gravity anomaly frequency domain information to zero, and then perform an inverse fast Fourier transform to calculate the time domain gravity anomaly information with linear and nonlinear residual errors eliminated.

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