A method and system for aeromagnetic compensation that integrates current magnetic interference suppression

Abstract

This application provides an aeromagnetic compensation method and system for fusing current magnetic interference suppression. The method includes determining a first interference term matrix that fuses aircraft maneuvering interference and geomagnetic gradient interference based on calibration flight data, and calculating a first compensation coefficient corresponding to the first interference term matrix based on a traditional aeromagnetic compensation model; performing aeromagnetic compensation on the aeromagnetic total field data generated during calibration flight based on the first compensation coefficient; extracting the target current interference signal from the compensated aeromagnetic total field data based on a mode decomposition method; fusing the target current interference signal to obtain a TLGI aeromagnetic compensation model based on the traditional aeromagnetic compensation model, and determining a second interference term matrix that fuses current magnetic interference based on the TLGI aeromagnetic compensation model; calculating a second compensation coefficient corresponding to the second interference term matrix, and performing aeromagnetic compensation on the aeromagnetic total field data generated during compensation flight based on the second compensation coefficient and the interference term generated during compensation flight.

Description

Technical Field

[0001] This application relates to the field of airborne magnetic measurement technology, and more specifically, to an airborne magnetic compensation method and system that integrates current magnetic interference suppression. Background Technology

[0002] Airborne magnetic surveying technology has been widely used in engineering surveys, military reconnaissance, and other fields. Currently, airborne magnetic surveying based on UAV platforms has advantages such as low site requirements, high mobility and flexibility, and long endurance, making it particularly advantageous for magnetic field measurement tasks with wide measurement ranges, complex terrain conditions, and hazardous measurement areas.

[0003] However, UAV-based airborne magnetic surveys are negatively affected by aircraft maneuvering interference, geomagnetic gradient interference, and current magnetic interference, making it difficult to distinguish abnormal target signals and diminishing the advantages of airborne magnetic surveys. Therefore, it is necessary to use airborne magnetic compensation technology to compensate for and suppress the aforementioned interferences.

[0004] Currently, commonly used aeromagnetic compensation models can only suppress the negative effects of aircraft maneuvering interference and geomagnetic gradient interference, with few studies addressing how to compensate for current magnetic interference. Current magnetic interference is generated by the electronic equipment within the UAV and the cables connecting the battery, servos, and rotor, and has a significant impact on the effectiveness of aeromagnetic measurements. Therefore, how to suppress current magnetic interference while improving the effectiveness of aeromagnetic compensation is the key problem addressed in this application. Summary of the Invention

[0005] The purpose of this application is to provide an aeromagnetic compensation method and system that integrates current magnetic interference suppression, which can more accurately and realistically reflect and suppress the magnetic interference experienced by the flight platform in actual flight tests, thereby improving the effect of aeromagnetic compensation.

[0006] This application also provides an aeromagnetic compensation method that integrates current magnetic interference suppression, including the following steps:

[0007] S1. Based on the corrected flight data, determine the first interference term matrix X, which integrates aircraft maneuvering interference and geomagnetic gradient interference, and calculate the first compensation coefficient corresponding to the first interference term matrix X based on the traditional aeromagnetic compensation model.

[0008] S2, based on the first compensation coefficient Correcting the aeromagnetic total field data H generated during flight M Perform aeromagnetic compensation to obtain the compensated total aeromagnetic field data.

[0009] S3. Based on the mode decomposition method, according to the selected optimal number of decomposition layers K i From the compensated aeromagnetic total field data Extract the target current interference signal h;

[0010] S4. Based on the traditional aeromagnetic compensation model, the target current interference signal h is fused to obtain the TLGI aeromagnetic compensation model, and based on the TLGI aeromagnetic compensation model, the second interference term matrix X of the fused current magnetic interference is determined. TLGI ;

[0011] S5. Calculate the second interference term matrix X. TLGI The corresponding second compensation coefficient The value of , and based on the second compensation coefficient The value of and the compensation for TLGI interference generated during flight The value of is used to integrate current magnetic interference suppression and compensate for the total aeromagnetic field data generated during flight. Perform aeromagnetic compensation

[0012] Secondly, embodiments of this application also provide an aeromagnetic compensation system that integrates current magnetic interference suppression. The system includes an interference fusion module, an aeromagnetic compensation module, and a current interference signal extraction module, wherein:

[0013] The interference fusion module is used to determine the first interference term matrix X, which fuses aircraft maneuvering interference and geomagnetic gradient interference, based on corrected flight data, and to calculate the first compensation coefficient corresponding to the first interference term matrix X based on a traditional aeromagnetic compensation model.

[0014] The aeromagnetic compensation module is used to base its calculations on the first compensation coefficient. Correcting the aeromagnetic total field data H generated during flight M Perform aeromagnetic compensation to obtain the compensated total aeromagnetic field data.

[0015] The current interference signal extraction module is used to extract the signal based on the mode decomposition method, according to the selected optimal decomposition level K. i From the compensated aeromagnetic total field data Extract the target current interference signal h;

[0016] The interference fusion module is further configured to fuse the target current interference signal h based on the traditional aeromagnetic compensation model to obtain a TLGI aeromagnetic compensation model, and based on the TLGI aeromagnetic compensation model, determine the second interference term matrix X of the fused current magnetic interference. TLGI ;

[0017] The aeromagnetic compensation module is also used to calculate the second interference term matrix X. TLGI The corresponding second compensation coefficient The value of , and based on the second compensation coefficient The value of and the compensation for TLGI interference generated during flight The value of is used to integrate current magnetic interference suppression and perform aeromagnetic compensation on the aeromagnetic total field data generated during compensation flight.

[0018] Thirdly, embodiments of this application also provide a readable storage medium, which includes a program for an aeromagnetic compensation method for fused current magnetic interference suppression. When the program for the fused current magnetic interference suppression aeromagnetic compensation method is executed by a processor, it implements the steps of an aeromagnetic compensation method for fused current magnetic interference suppression as described in any of the preceding claims.

[0019] As can be seen from the above, the aeromagnetic compensation method, system, and readable storage medium for fusing current magnetic interference suppression provided in this application embodiment determine a first interference term matrix that fuses aircraft maneuvering interference and geomagnetic gradient interference based on correction flight data, and calculate a first compensation coefficient corresponding to the first interference term matrix based on a traditional aeromagnetic compensation model; perform aeromagnetic compensation on the aeromagnetic total field data generated during correction flight based on the first compensation coefficient; extract the target current interference signal from the compensated aeromagnetic total field data based on the mode decomposition method; fuse the target current interference signal to obtain a TLGI aeromagnetic compensation model based on the traditional aeromagnetic compensation model, and determine a second interference term matrix that fuses current magnetic interference based on the TLGI aeromagnetic compensation model; calculate the second compensation coefficient corresponding to the second interference term matrix, and perform aeromagnetic compensation on the aeromagnetic total field data generated during compensation flight based on the second compensation coefficient and the interference term generated during compensation flight. This application, on the one hand, establishes a TLGI aeromagnetic compensation model by integrating target current interference signals on the basis of traditional aeromagnetic compensation models, and extracts current interference signals based on mode decomposition methods and at the selected optimal number of decomposition layers, which can further avoid mode aliasing and improve the accuracy of signal extraction. On the other hand, by combining effective estimation of compensation coefficients, it can effectively compensate for current interference present in aeromagnetic data, significantly improve the improvement ratio of aeromagnetic compensation, and enhance the quality of airborne geophysical exploration.

[0020] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing embodiments of this application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A flowchart illustrating an aeromagnetic compensation method that integrates current magnetic interference suppression, provided as an embodiment of this application;

[0023] Figure 2 This application provides an overall implementation flowchart of an aeromagnetic compensation method that integrates current magnetic interference suppression.

[0024] Figure 3 This is an example diagram illustrating the application of the mode decomposition method;

[0025] Figure 4 The total field image before aeromagnetic compensation;

[0026] Figure 5 The image shows the total field after compensation based on the traditional aeromagnetic compensation model.

[0027] Figure 6 The image shows the total field image after compensation based on the TLGI aeromagnetic compensation model.

[0028] Figure 7 This is a schematic diagram of an aeromagnetic compensation system that integrates current magnetic interference suppression, provided as an embodiment of this application. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0030] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] Please refer to Figure 1 , Figure 1 This is a flowchart of an aeromagnetic compensation method that integrates current magnetic interference suppression in some embodiments of this application (which can also be combined with...) Figure 2 (Understanding the overall implementation process). This method includes the following steps:

[0032] Step S1: Based on the corrected flight data, determine the first interference term matrix X, which integrates aircraft maneuvering interference and geomagnetic gradient interference, and calculate the first compensation coefficient corresponding to the first interference term matrix X based on the traditional aeromagnetic compensation model.

[0033] Specifically, the corrected flight data includes the aircraft magnetic interference H obtained by bandpass filtering the total aeromagnetic field data measured by the optical magnetometer. TLG And a first interference term matrix X calculated from fluxgate measurement data, wherein the first interference term matrix X is composed of aircraft maneuver interference term and geomagnetic gradient interference term.

[0034] It should be noted that in step S1, the traditional aeromagnetic compensation model includes:

[0035] H TLG =Xβ; (1)

[0036] Wherein, β is the 21 compensation coefficients corresponding to the first interference term matrix.

[0037] Furthermore, given H TLG When determining the value of X, in this embodiment, the value of the compensation coefficient β will be calculated based on the least squares estimation method, that is, the first compensation coefficient corresponding to the first interference term matrix X will be calculated.

[0038] Step S2, based on the first compensation coefficient Correcting the aeromagnetic total field data H generated during flight M Perform aeromagnetic compensation to obtain the compensated total aeromagnetic field data.

[0039] Specifically, after solving for the first compensation coefficient... Then, the first interference term matrix X and Substituting into formula (1), the corresponding aircraft magnetic interference is estimated.

[0040] In one specific embodiment, the raw aeromagnetic total field data H generated during the correction flight is used. M minus The compensated aeromagnetic total field data can then be obtained.

[0041] Step S3, based on the mode decomposition method, according to the selected optimal number of decomposition layers K i From the compensated aeromagnetic total field data The target current interference signal h is extracted from it.

[0042] Specifically, in the current embodiment, the optimal decomposition layer number K will be combined. i The compensated aeromagnetic total field data Decompose into K i -1 modal component, and record the center frequency of each modal component. For the specific decomposition form, please refer to [reference needed]. Figure 3 To understand this, in the current embodiment, the frequency of the current interference signal will be used as a basis, starting from this K... i Multiple target modal components are selected from one modal component, wherein the center frequencies of the multiple target modal components are all less than or equal to the frequency of the current interference signal.

[0043] For example, please refer to... Figure 3 Since the center frequency of the first modal component obtained from the decomposition reaches its maximum value of 3.2789 for the first time when the decomposition level is 8, the optimal decomposition level can be determined to be 8. Furthermore, since the frequency of current interference signals is typically less than 1 Hz, it is possible to select multiple target modal components with frequencies less than 1 Hz from the 7 modal components included in the 8th level. Because the center frequencies of the 4th to 7th modal components in the 8th level are all less than 1 Hz, the current interference signal can be constructed based on these 4th to 7th modal components.

[0044] Step S4: Based on the traditional aeromagnetic compensation model, the target current interference signal h is fused to obtain the TLGI aeromagnetic compensation model, and based on the TLGI aeromagnetic compensation model, the second interference term matrix X of the fused current magnetic interference is determined. TLGI .

[0045] Specifically, the combined second interference term matrix Where u1, u2, and u3 represent the cosine values ​​of the direction angles formed by the geomagnetic field and the three axes of the flight platform, respectively; g1, g2, and g3 are the location information of the flight platform, representing longitude, latitude, and altitude, respectively.

[0046] It should be noted that the Biot-Savart law is used in the current embodiment to determine the static magnetic field generated by the quasi-static current. According to the Biot-Savart law, the current-magnetic interference experienced by the optically pumped magnetometer is expressed as:

[0047]

[0048] Where μ0 is the free permeability and I is the current. Let be the unit vector pointing from the current element to the optically pumped magnetometer, and r be the difference between the vector positions of the current element and the optically pumped magnetometer. Let The magnetic interference of the current measured by the optically pumped magnetometer can be further expressed as:

[0049]

[0050] Since the positions of the cable and the optical pump magnetometer are fixed in the same flight experiment, therefore in formula (2) Since neither r nor r will change, then in formula (3) This term can be considered a constant coefficient. Therefore, based on formula (3), the current disturbance compensation model can be transformed into:

[0051] B I =qh; (4)

[0052] Where q is the compensation coefficient in the current disturbance compensation model, and... Proportional. h is a signal that is proportional to the current I.

[0053] It should be noted that in the current embodiment, the current compensation model (i.e., Equation 4) is combined with the traditional aeromagnetic compensation model (i.e., Equation 1) to obtain the TLGI aeromagnetic compensation model:

[0054]

[0055] Among them, H TLGI To account for aircraft magnetic interference caused by current interference, X TLGI Let β be the matrix of the second interference term. TLGI It is X TLGI The corresponding compensation coefficients. It should be noted that subsequent work will use the TLGI aeromagnetic compensation model to compensate for current interference in aeromagnetism and evaluate the aeromagnetic compensation effect.

[0056] Step S5, calculate the second interference term matrix X TLGI The corresponding second compensation coefficient The value of , and based on the second compensation coefficient The value of and the compensation for TLGI interference generated during flight The value of is used to integrate current magnetic interference suppression and compensate for the total aeromagnetic field data generated during flight. Perform aeromagnetic compensation.

[0057] Specifically, after obtaining the second compensation coefficient The value of and the compensation for TLGI interference generated during flight After determining the value of , the estimated value of magnetic interference under compensated flight can be calculated using the following formula (6).

[0058]

[0059] Furthermore, the total field data measured by the optically pumped magnetometer during flight will be compensated. minus This allows for the completion of aeromagnetic compensation for the suppression of fused current magnetic interference.

[0060] Based on formula (6), it should be noted that in order to suppress multicollinearity in the TLGI interference term during correction flight, while ensuring low bias in coefficient estimation, the stability of aeromagnetic compensation is improved. In the current embodiment, a ridge parameter k and a bias parameter d are introduced based on least squares to perform a second compensation coefficient calculation. The calculation method is described in subsequent embodiments.

[0061] As can be seen from the above, the aeromagnetic compensation method for fusing current magnetic interference suppression disclosed in this application determines a first interference term matrix that fuses aircraft maneuvering interference and geomagnetic gradient interference based on calibration flight data, and calculates a first compensation coefficient corresponding to the first interference term matrix based on a traditional aeromagnetic compensation model; performs aeromagnetic compensation on the aeromagnetic total field data generated during calibration flight based on the first compensation coefficient; extracts the target current interference signal from the compensated aeromagnetic total field data based on mode decomposition; fuses the target current interference signal to obtain a TLGI aeromagnetic compensation model based on the traditional aeromagnetic compensation model, and determines a second interference term matrix that fuses current magnetic interference based on the TLGI aeromagnetic compensation model; calculates a second compensation coefficient corresponding to the second interference term matrix, and performs aeromagnetic compensation on the aeromagnetic total field data generated during compensation flight based on the second compensation coefficient and the interference term generated during compensation flight. This application, on the one hand, establishes a TLGI aeromagnetic compensation model by fusing the target current interference signal on the basis of a traditional aeromagnetic compensation model, and on the other hand, extracts the current interference signal based on the selected optimal decomposition level using a mode decomposition method, which can further avoid mode aliasing and improve the accuracy of signal extraction. On the other hand, by combining effective estimation of the compensation coefficient, it is possible to effectively compensate for the current interference present in aeromagnetic data, significantly improve the improvement ratio of aeromagnetic compensation, and improve the quality of airborne geophysical exploration.

[0062] In one embodiment, step S1, determining the first interference term matrix X, which fuses aircraft maneuvering interference and geomagnetic gradient interference, based on corrected flight data, includes:

[0063] Step S11: Based on the corrected flight data, determine the aircraft maneuvering interference term x. i ,in, u1, u2, u3 represent the cosine values ​​of the direction angles formed by the geomagnetic field and the three axes of the flight platform, respectively, and du1 / dt, du2 / dt, du3 / dt represent the time derivatives of u1, u2, u3, respectively.

[0064] Step S12: Based on the corrected flight data, determine the geomagnetic gradient disturbance term x. j , where x j = (g1, g2, g3), where g1, g2, and g3 represent the longitude, latitude, and altitude of the flight platform, respectively.

[0065] Step S13, combine the aircraft maneuvering interference item x i and the geomagnetic gradient disturbance term x j The first interference term matrix X = (x) is obtained by integrating aircraft maneuvering interference and geomagnetic gradient interference. i x j ).

[0066] Based on steps S11 and S13, it should be noted that the specific calculation form of the traditional aeromagnetic compensation model can be referenced based on the following formula (7):

[0067]

[0068] Based on formula (7), it should be noted that after expanding each term in formula (7), H can be obtained. TLG =Xβ. Where, Let β be the matrix of the first interference term, where β = [a i ,b ij ,c ij ,d i ] T These are the 22 compensation coefficients corresponding to the interference term matrix X.

[0069] It should be further noted that the aircraft maneuvering interference item x in steps S11 and S12 i and the geomagnetic gradient disturbance term x j This can be understood based on the expansion of the above formula (2), and will not be explained further at this time.

[0070] In one embodiment, in step S1, the calculation of the first compensation coefficient corresponding to the first interference term matrix X is performed. include:

[0071] Step S14: Based on the traditional aeromagnetic compensation model, the first compensation coefficient corresponding to the first interference term matrix X is calculated through least squares estimation.

[0072]

[0073] Among them, H TLG To analyze the measured total aeromagnetic field data H M The magnetic field value obtained after bandpass filtering.

[0074] In the above embodiments, the advantages of least squares regression are utilized to improve the robustness of the fitting algorithm and further ensure the stability and reliability of the compensation coefficients.

[0075] In one embodiment, in step S2, the first compensation coefficient is used... Correcting the aeromagnetic total field data H generated during flight M Perform aeromagnetic compensation to obtain the compensated total aeromagnetic field data. include:

[0076] Step S21, based on the first compensation coefficient And the first interference term matrix X, from which the first aircraft magnetic interference term is estimated.

[0077] Specifically, based on the first compensation coefficient And the first interference term matrix X, through The magnetic interference term of the first aircraft can then be calculated and estimated.

[0078] Step S22, calibrating the aeromagnetic total field data H generated during flight. M Based on this, remove the first aircraft magnetic interference term. Compensated aeromagnetic total field data

[0079] Specifically, the raw aeromagnetic total field data H generated during the correction flight is used. M minus The compensated aeromagnetic total field data can then be obtained.

[0080] In one embodiment, in step S3, the mode decomposition method, based on the selected optimal number of decomposition layers K, i From the compensated aeromagnetic total field data The target current interference signal h is extracted, including:

[0081] Step S31: Using the variational mode decomposition method, select successively increasing decomposition mode numbers K to analyze the compensated aeromagnetic total field data. Perform several decomposition processes, where K is a natural number greater than 1.

[0082] Specifically, variational mode decomposition (VMD) refers to a method that uses iterative search for the optimal solution of a variational model to determine the center frequency and bandwidth of each decomposed component. It is a completely non-recursive model, effectively avoiding problems such as mode aliasing, over-envelope, under-envelope, and boundary effects. It has advantages such as good accuracy in filtering out target anomalous signals from complex data and good resistance to noise interference. The number of decomposed modes, K, is a key parameter of the variational decomposition method; the optimal number of decomposition levels, K, needs to be determined before extracting current interference signals. i .

[0083] In the current embodiment, the center frequency method is considered to determine the optimal number of decomposition layers K. i Specifically, starting with K=2, the value of K will be continuously increased, and the center frequencies of each modal component obtained from the decomposition under different K values ​​will be calculated (the specific decomposition form can be found in [reference]). Figure 3 (To understand).

[0084] Step S32, after determining the number of decomposition modes to be K i When the center frequency of the first module component obtained from the decomposition reaches its maximum value for the first time, the K value of the current decomposition mode number is set. i As the optimal number of decomposition layers.

[0085] Specifically, in this embodiment, the trend of the center frequency of the first module component in each layer is used to determine when the center frequency of the first module component first reaches its maximum value, and the decomposition layer number corresponding to the maximum value is taken as the optimal decomposition layer number. The specific analysis method can also be found in the aforementioned embodiments, and will not be repeated here.

[0086] Step S33, based on the signal frequency range of the current interference signal, from the K contained in the optimal decomposition layer i From one modal component, multiple target modal components are selected.

[0087] Step S34: Based on the multiple target modal components, construct the target current interference signal h.

[0088] Based on steps S33 and S34, it should be noted that in the current embodiment, K included within the optimal decomposition layer will be... i From the -1 modal components, select multiple target modal components with center frequencies lower than the target signal frequency, and construct the target current interference signal h based on these target modal components.

[0089] In the above embodiments, the mode decomposition method is used to decompose the signal containing current interference from the compensated aeromagnetic total field signal. By selecting the optimal number of decomposition layers, mode aliasing can be avoided and the accuracy of signal extraction can be improved.

[0090] In one embodiment, step S34, which involves constructing the target current interference signal h based on the plurality of target mode components, includes:

[0091] Step S341: Based on the multiple target mode components, an initial current interference signal h' is constructed.

[0092] Step S342: When it is determined that there is a target abnormal signal with overlapping frequency bands in the initial current interference signal h', the target current interference signal h is decomposed from the initial current interference signal h' based on the singular spectrum analysis method.

[0093] Specifically, since the frequency bands of the target abnormal signal and the current interference signal overlap, the initial current interference signal h' extracted by the variational mode decomposition method may simultaneously contain both the target abnormal signal and the current interference signal. Therefore, in this embodiment, singular spectrum analysis is considered to further separate the initial current interference signal h' to extract the pure current interference signal and suppress the abnormal signal.

[0094] In the above embodiments, considering that the frequency bands of the abnormal signal and the current interference signal overlap, the initial current interference signal h' is further denoised using the singular spectrum analysis method to ensure the accuracy and reliability of the current interference signal extraction.

[0095] In one embodiment, step S342, whereby the target current interference signal h is obtained from the initial current interference signal h' based on the singular spectrum analysis method, includes:

[0096] Step S3421: Preset the number of sampling points N and the optimal window length L for singular spectrum analysis.

[0097] Specifically, in the current embodiment, the preset number of sampling points is N, and the optimal window length L for singular spectrum analysis is selected as 70. In a specific implementation case, during compensated flight, the value of this sampling point can be set to 2000-3000. This application does not limit the specific value of the sampling point, and it can be set according to the actual application requirements.

[0098] Step S3422: Based on the number of sampling points N and the optimal window length L, the initial current interference signal h' is converted into an L×k trajectory matrix M, where k=N-l+1.

[0099] Step S3423, let G = MM T Based on matrix G, eigenvalue decomposition is performed to obtain the eigenvalue set λ1, λ2, ..., λ3. L and the feature vector set v1, v2, ..., v L .

[0100] Step S3424, based on the feature vector set v1, v2, ..., v L The trajectory matrix M contains L components M1, M2, ..., M. L .

[0101] For example, the i-th component of the trajectory matrix M is expressed as follows: The calculation methods for the remaining components can be found in M. i The calculation method is not explained further at this time.

[0102] Step S3425, transfer these L components M1, M2, ..., M L Each of these time series is converted into its corresponding one-dimensional time series, and the resulting one-dimensional time series are combined to obtain an L×N reconstruction matrix Y.

[0103] For example, the i-th component M of the trajectory matrix M i One-dimensional time series S n It can be calculated using the following formula:

[0104]

[0105] The calculation methods for the one-dimensional time series of the remaining components can be referred to the above S. n The calculation method is not explained further at this time.

[0106] Step S3426, based on the eigenvalue set λ1, λ2, ..., λ L The contribution rate R is calculated. When the contribution rate R obtained at the p-th order is greater than the preset contribution rate threshold, the target current interference signal h is reconstructed based on the multiple target one-dimensional time series of the p-th to L-th orders in the reconstruction matrix Y.

[0107] Specifically, in the current embodiment, the following formula will be used to calculate the eigenvalues ​​based on the feature set λ1, λ2, ..., λ L Calculate the contribution rate R:

[0108]

[0109] In a specific embodiment, this application sets the contribution rate threshold to 0.8. When the contribution rate R≥0.8, the one-dimensional time series of the first to pth order in the reconstruction matrix Y will be reconstructed into the target abnormal signal, and the remaining part (i.e., the pth to Lth order) of multiple target one-dimensional time series will be reconstructed into the target current interference signal h.

[0110] In the above embodiments, by selecting an appropriate window length L and contribution rate threshold, the reliability of extracting the target current interference signal h is further ensured, providing an important reference for subsequent effective compensation for current interference in aeromagnetic systems.

[0111] In one embodiment, in step S5, the second interference term matrix X is calculated. TLGI The corresponding second compensation coefficient The possible values ​​for include:

[0112] Step S51, based on matrix The smallest eigenvalue λ min and the largest eigenvalue λ max Determine the value of the ridge parameter k.

[0113] Specifically, in the current embodiment, in order to make the matrix The condition number decreases to 10 (at which point multicollinearity has little effect on coefficient estimation), and the matrix is ​​determined. The smallest eigenvalue λ min and the largest eigenvalue λ max The value of the ridge parameter k will be calculated according to the following formula:

[0114]

[0115] It should be noted that the aforementioned condition number is an indicator for measuring the degree of multicollinearity of a matrix. The higher the condition number, the more severe the multicollinearity of the matrix, which will lead to unstable results in operations such as matrix inversion, and consequently, unstable calculated compensation coefficients.

[0116] Step S52: Introduce the unknown bias parameter d and the value of the ridge parameter k, and construct the second compensation coefficient using the following formula. Mathematical calculation model:

[0117]

[0118] Where I is the identity matrix.

[0119] Specifically, in order to suppress multicollinearity in the interference terms of TLGI during correction flight and improve the stability of aeromagnetic compensation while ensuring low bias in coefficient estimation, the current embodiment considers introducing ridge parameter k and bias parameter d based on least squares.

[0120] Step S53: Based on the mathematical calculation model, determine the second compensation coefficient. The mean square error is calculated, and the value of the bias parameter d is obtained based on the mean square error.

[0121] Specifically, The mean squared error (MSE) is expressed as follows:

[0122]

[0123] Where σ is the standard deviation of the aeromagnetic data; λ i For matrix The i-th eigenvalue; α i The compensation coefficient regularization form is α = P Τ Let β be the i-th element, and P be the orthogonal matrix after orthogonal decomposition. To determine the bias parameter d under minimum MSE, find the derivative of h(d) with respect to d, then we have:

[0124]

[0125] It can be observed that when d equals When h(d) reaches its minimum value, the value of the bias parameter d can be calculated using the following formula:

[0126]

[0127] Step S54: Substitute the values ​​of the bias parameter d and the ridge parameter k into the mathematical calculation model to calculate the second interference term matrix X. TLGI The corresponding second compensation coefficient The value of .

[0128] Specifically, when determining the value of the bias parameter d based on formula (15) and the value of the ridge parameter k based on formula (11), substituting the values ​​of these two parameters into formula (12) yields the second interference term matrix X. TLGI The corresponding second compensation coefficient The value of .

[0129] In the above embodiments, the ridge parameter k and the bias parameter d are introduced on the basis of least squares, which can improve the stability of aeromagnetic compensation while ensuring low bias in coefficient estimation.

[0130] Please refer to Figure 4 To verify the effectiveness of the aeromagnetic compensation method proposed in this application, comparative experiments were also conducted on the compensated flight data during implementation. Figure 4 It is known that in the total field image before compensation, the aeromagnetic total field is greatly negatively affected by magnetic interference, making it difficult to observe the true trend of the aeromagnetic total field. Therefore, this application uses the traditional aeromagnetic compensation model (as shown in formula (1)) and the TLGI model proposed in this application (as shown in formula (5)) for aeromagnetic compensation, respectively. The total field images after compensation by the two models are as follows: Figures 5-6 As shown. By Figures 5-6It is evident that, compared to traditional aeromagnetic compensation models, the total magnetic field curve after compensation by the TLGI model is smoother and better reflects the trend of magnetic field changes. This also indicates that the TLGI model proposed in this application can more accurately reflect and suppress the magnetic interference experienced by the flight platform during actual flight tests, thereby improving the effectiveness of aeromagnetic compensation.

[0131] Please refer to Figure 7 This application discloses an aeromagnetic compensation system that integrates current magnetic interference suppression. The system includes an interference fusion module, an aeromagnetic compensation module, and a current interference signal extraction module, wherein:

[0132] The interference fusion module is used to determine the first interference term matrix X, which fuses aircraft maneuvering interference and geomagnetic gradient interference, based on corrected flight data, and to calculate the first compensation coefficient corresponding to the first interference term matrix X based on a traditional aeromagnetic compensation model.

[0133] The aeromagnetic compensation module is used to base its calculations on the first compensation coefficient. Correcting the aeromagnetic total field data H generated during flight M Perform aeromagnetic compensation to obtain the compensated total aeromagnetic field data.

[0134] The current interference signal extraction module is used to extract the signal based on the mode decomposition method, according to the selected optimal decomposition level K. i From the compensated aeromagnetic total field data The target current interference signal h is extracted from it.

[0135] The interference fusion module is further configured to fuse the target current interference signal h based on the traditional aeromagnetic compensation model to obtain a TLGI aeromagnetic compensation model, and based on the TLGI aeromagnetic compensation model, determine the second interference term matrix X of the fused current magnetic interference. TLGI .

[0136] The aeromagnetic compensation module is also used to calculate the second interference term matrix X. TLGI The corresponding second compensation coefficient The value of , and based on the second compensation coefficient The value of and the compensation for TLGI interference generated during flight The value of is used to integrate current magnetic interference suppression and perform aeromagnetic compensation on the aeromagnetic total field data generated during compensation flight.

[0137] In one embodiment, the modules in the system are also used to perform the methods in any optional implementation of the above embodiments.

[0138] As can be seen from the above, the aeromagnetic compensation system for integrating current magnetic interference suppression disclosed in this application determines a first interference term matrix that integrates aircraft maneuvering interference and geomagnetic gradient interference based on calibration flight data, and calculates a first compensation coefficient corresponding to the first interference term matrix based on a traditional aeromagnetic compensation model; performs aeromagnetic compensation on the aeromagnetic total field data generated during calibration flight based on the first compensation coefficient; extracts the target current interference signal from the compensated aeromagnetic total field data based on the mode decomposition method; integrates the target current interference signal to obtain a TLGI aeromagnetic compensation model based on the traditional aeromagnetic compensation model, and determines a second interference term matrix that integrates current magnetic interference based on the TLGI aeromagnetic compensation model; calculates a second compensation coefficient corresponding to the second interference term matrix, and performs aeromagnetic compensation on the aeromagnetic total field data generated during compensation flight based on the second compensation coefficient and the interference term generated during compensation flight. This application, on the one hand, establishes a TLGI aeromagnetic compensation model by integrating the target current interference signal based on the traditional aeromagnetic compensation model, and on the other hand, extracts the current interference signal based on the selected optimal decomposition level using the mode decomposition method, which can further avoid mode aliasing and improve the accuracy of signal extraction. On the other hand, by combining effective estimation of the compensation coefficient, it is possible to effectively compensate for the current interference present in aeromagnetic data, significantly improve the improvement ratio of aeromagnetic compensation, and improve the quality of airborne geophysical exploration.

[0139] This application provides a readable storage medium. When the computer program is executed by a processor, it performs the method in any optional implementation of the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0140] The aforementioned readable storage medium, based on calibration flight data, determines a first interference term matrix that integrates aircraft maneuvering interference and geomagnetic gradient interference, and calculates a first compensation coefficient corresponding to the first interference term matrix based on a traditional aeromagnetic compensation model; based on the first compensation coefficient, performs aeromagnetic compensation on the aeromagnetic total field data generated during calibration flight; based on mode decomposition, extracts the target current interference signal from the compensated aeromagnetic total field data; based on the traditional aeromagnetic compensation model, fuses the target current interference signal to obtain a TLGI aeromagnetic compensation model, and based on the TLGI aeromagnetic compensation model, determines a second interference term matrix that integrates current magnetic interference; calculates a second compensation coefficient corresponding to the second interference term matrix, and performs aeromagnetic compensation on the aeromagnetic total field data generated during compensation flight based on the second compensation coefficient and the interference term generated during compensation flight. This application, on the one hand, establishes a TLGI aeromagnetic compensation model by fusing the target current interference signal on the basis of a traditional aeromagnetic compensation model, and on the other hand, extracts the current interference signal based on a mode decomposition method at a selected optimal decomposition level, which can further avoid mode aliasing and improve the accuracy of signal extraction. On the other hand, by combining effective estimation of the compensation coefficient, it is possible to effectively compensate for the current interference present in aeromagnetic data, significantly improve the improvement ratio of aeromagnetic compensation, and improve the quality of airborne geophysical exploration.

[0141] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0142] Furthermore, 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.

[0143] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0144] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0145] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An aeromagnetic compensation method integrating current magnetic interference suppression, characterized in that, Includes the following steps: S1. Based on the corrected flight data, determine the first interference term matrix X, which integrates aircraft maneuvering interference and geomagnetic gradient interference, and calculate the first compensation coefficient corresponding to the first interference term matrix X based on the traditional aeromagnetic compensation model. S2, based on the first compensation coefficient Correcting the aeromagnetic total field data H generated during flight M Perform aeromagnetic compensation to obtain the compensated total aeromagnetic field data. S3. Based on the mode decomposition method, according to the selected optimal number of decomposition layers K i From the compensated aeromagnetic total field data Extract the target current interference signal h; S4. Based on the traditional aeromagnetic compensation model, the target current interference signal h is fused to obtain the TLGI aeromagnetic compensation model, and based on the TLGI aeromagnetic compensation model, the second interference term matrix X of the fused current magnetic interference is determined. TLGI ; S5. Calculate the second interference term matrix X. TLGI The corresponding second compensation coefficient The value of , and based on the second compensation coefficient The value of and the compensation for TLGI interference generated during flight The value of is used to integrate current magnetic interference suppression and compensate for the total aeromagnetic field data generated during flight. Perform aeromagnetic compensation.

2. The method according to claim 1, characterized in that, In step S1, determining the first interference term matrix X, which integrates aircraft maneuvering interference and geomagnetic gradient interference, based on the corrected flight data, includes: S11. Based on the corrected flight data, determine the aircraft maneuvering interference term x. i ,in, u1, u2, u3 represent the cosine values ​​of the direction angles formed by the geomagnetic field and the three axes of the flight platform, respectively; du1 / dt, du2 / dt, du3 / dt represent the time derivatives of u1, u2, u3, respectively. S12. Based on the corrected flight data, determine the geomagnetic gradient disturbance term x. j , where x j = (g1, g2, g3), where g1, g2, and g3 represent the longitude, latitude, and altitude of the flight platform, respectively; S13, Combining the aforementioned aircraft maneuvering interference item x i and the geomagnetic gradient disturbance term x j The first interference term matrix X = (x) is obtained by integrating aircraft maneuvering interference and geomagnetic gradient interference. i ,x j ).

3. The method according to claim 2, characterized in that, In step S1, the calculation of the first compensation coefficient corresponding to the first interference term matrix X is performed. include: S14. Based on the traditional aeromagnetic compensation model, the first compensation coefficient corresponding to the first interference term matrix X is calculated through least squares estimation. Among them, H TLG To analyze the measured total aeromagnetic field data H M The magnetic field value obtained after bandpass filtering.

4. The method according to claim 1, characterized in that, In step S2, the compensation coefficient is based on the first compensation coefficient. Correcting the aeromagnetic total field data H generated during flight M Perform aeromagnetic compensation to obtain the compensated total aeromagnetic field data. include: S21, Based on the first compensation coefficient And the first interference term matrix X, from which the first aircraft magnetic interference term is estimated. S22, Total aeromagnetic field data H generated during correction flight M Based on this, remove the first aircraft magnetic interference term. Compensated aeromagnetic total field data 5. The method according to claim 1, characterized in that, In step S3, the mode decomposition method, based on the selected optimal number of decomposition layers K, i From the compensated aeromagnetic total field data The target current interference signal h is extracted, including: S31. Using the variational mode decomposition method, select successively increasing decomposition mode numbers K to analyze the compensated aeromagnetic total field data. Perform several decomposition processes, where K is a natural number greater than 1; S32, When determining the number of decomposition modes, take K i When the center frequency of the first module component obtained from the decomposition reaches its maximum value for the first time, the K value of the current decomposition mode number is set. i As the optimal number of decomposition levels; S33. Based on the signal frequency range of the current interference signal, from the K contained in the optimal decomposition layer. i From one modal component, select multiple target modal components; S34. Based on the multiple target modal components, the target current interference signal h is constructed.

6. The method according to claim 5, characterized in that, In step S34, constructing the target current interference signal h based on the multiple target mode components includes: S341. Based on the multiple target modal components, an initial current interference signal h' is constructed; S342. When it is determined that there is a target abnormal signal with overlapping frequency bands in the initial current interference signal h', the target current interference signal h is decomposed from the initial current interference signal h' based on the singular spectrum analysis method.

7. The method according to claim 6, characterized in that, In step S342, the decomposition of the initial current interference signal h from the singular spectrum analysis method to obtain the target current interference signal h includes: S3421, preset number of sampling points N, and optimal window length L for singular spectrum analysis; S3422. Based on the number of sampling points N and the optimal window length L, the initial current interference signal h' is converted into an L×k trajectory matrix M, where k=N-L+1; S3423, Let G = MM T Based on matrix G, eigenvalue decomposition is performed to obtain the eigenvalue set λ1,λ2,K,λ. L and the set of feature vectors v1, v2, K, v L ; S3424, Based on the feature vector set v1, v2, K, v L The trajectory matrix M contains L components M1, M2, ..., M. L ; S3425, Let these L components M1, M2, ..., M L Each of these is converted into a corresponding one-dimensional time series, and the resulting one-dimensional time series are combined to obtain an L×N reconstruction matrix Y. S3426. Based on the eigenvalue set λ1, λ2, K, λ L The contribution rate R is calculated. When the contribution rate R obtained at the p-th order is greater than the preset contribution rate threshold, the target current interference signal h is reconstructed based on the multiple target one-dimensional time series of the p-th to L-th orders in the reconstruction matrix Y.

8. The method according to claim 1, characterized in that, In step S5, the second interference term matrix X is calculated. TLGI The corresponding second compensation coefficient The possible values ​​for include: S51, Matrix-based The smallest eigenvalue λ min and the largest eigenvalue λ max Determine the value of the ridge parameter k; S52. Introducing the unknown bias parameter d and the value of the ridge parameter k, the second compensation coefficient is constructed using the following formula. Mathematical calculation model: Where I is the identity matrix; S53. Based on the mathematical calculation model, determine the second compensation coefficient. The mean square error is calculated, and the value of the bias parameter d is obtained based on the mean square error. S54. Substitute the values ​​of the bias parameter d and the ridge parameter k into the mathematical calculation model to calculate the second interference term matrix X. TLGI The corresponding second compensation coefficient The value of .

9. An aeromagnetic compensation system integrating current magnetic interference suppression, characterized in that, The system includes an interference fusion module, an aeromagnetic compensation module, and a current interference signal extraction module, wherein: The interference fusion module is used to determine the first interference term matrix X, which fuses aircraft maneuvering interference and geomagnetic gradient interference, based on corrected flight data, and to calculate the first compensation coefficient corresponding to the first interference term matrix X based on a traditional aeromagnetic compensation model. The aeromagnetic compensation module is used to base its calculations on the first compensation coefficient. Correcting the aeromagnetic total field data H generated during flight M Perform aeromagnetic compensation to obtain the compensated total aeromagnetic field data. The current interference signal extraction module is used to extract the signal based on the mode decomposition method, according to the selected optimal decomposition level K. i From the compensated aeromagnetic total field data Extract the target current interference signal h; The interference fusion module is further configured to fuse the target current interference signal h based on the traditional aeromagnetic compensation model to obtain a TLGI aeromagnetic compensation model, and based on the TLGI aeromagnetic compensation model, determine the second interference term matrix X of the fused current magnetic interference. TLGI ; The aeromagnetic compensation module is also used to calculate the second interference term matrix X. TLGI The corresponding second compensation coefficient The value of , and based on the second compensation coefficient The value of and the compensation for TLGI interference generated during flight The value of is used to integrate current magnetic interference suppression and perform aeromagnetic compensation on the aeromagnetic total field data generated during compensation flight.

10. A readable storage medium, characterized in that, The readable storage medium includes a program for aeromagnetic compensation method that integrates current magnetic interference suppression, which, when executed by a processor, implements the steps of the method as described in any one of claims 1 to 8.

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