Aviation Magnetic Compensation Method and System for Suppressing Geological Magnetic Interference

Abstract

The present invention provides an airborne magnetic compensation method and system for suppressing geological magnetic interference, including: constructing a geological magnetic interference compensation model for the detection area by using a surface spline function; linearly expanding the traditional magnetic interference model by using the geological magnetic interference compensation model to establish a new airborne magnetic compensation model including the geological magnetic interference compensation model in the detection area; calibrating the flight of the detection platform, respectively collecting the total magnetic field, three components of the vector magnetoresistance, longitude, latitude and altitude information, and calculating and obtaining magnetic compensation coefficients; in actual detection, using the new airborne magnetic compensation model, magnetic compensation coefficients, the real-time total magnetic field of the magnetometer, three components of the vector magnetoresistance and the real-time position information of the detection platform to perform high-precision real-time compensation for platform maneuver magnetic interference, geomagnetic gradient magnetic interference and geological magnetic interference. Applying the technical solution of the present invention can solve the technical problem in the prior art that the geological magnetic interference in the actual detection area affects the effective discrimination of target signals.

Description

Technical Field

[0001] The present invention relates to the technical fields of aviation magnetic compensation and aviation magnetic detection, and particularly relates to an aviation magnetic compensation method and system for suppressing geological magnetic interference. Background Art

[0002] Aviation magnetic detection is currently the main non-acoustic means for underwater target detection. This technology uses an unmanned or manned aircraft equipped with a high-sensitivity aviation magnetometer to measure the Earth's magnetic field in real time in a complex magnetic field environment to detect and analyze ferromagnetic targets submerged therein. Usually, the signal intensity of the target to be detected is often much lower than the magnetic field interference existing in the surrounding environment, and the frequency bands of the two overlap. Therefore, the key to restricting the performance of aviation magnetic detection lies in the efficient compensation level for aviation magnetic interference.

[0003] In actual detection, the mobile magnetic interference of the airborne platform, the geomagnetic gradient magnetic interference, and the geological magnetic interference will all significantly affect the final detection result. Currently, the mainstream aviation magnetic compensation algorithm mainly adopts the traditional compensation model proposed by Tolles and Lawson (hereinafter referred to as the T-L model). However, this model only considered the interference magnetic field generated by ferromagnetic substances on the moving platform at the beginning of its design, and did not consider the geomagnetic gradient or geological magnetic interference. The geomagnetic field, that is, the Earth's main magnetic field, is relatively stable, and its intensity and direction change little on a relatively long time scale and approximately linearly change in the north-south direction in a small area. Therefore, if the detection area is small and the geological composition is simple, a first-order linear model constructed using the platform position information can be used to approximate the geomagnetic gradient magnetic interference in this area.

[0004] Geomagnetic interference in geology stems from the magnetic heterogeneity of different rock types in the Earth's crust. Areas in the lithosphere containing magnetic minerals such as iron ore exhibit stronger magnetism in the geomagnetic field. This magnetic heterogeneity is not only affected by the geomagnetic field but also becomes more prominent due to geological tectonic movements. Especially in fault zones, the stress and deformation of the crust trigger the fracture and dislocation of rocks, leading to abnormal distribution of magnetic minerals. At the same time, the magnetic anomalies in these fault zones are directly related to magmatic activities and rock fractures in geological structures. For example, during magmatic activities, the magnetic minerals in rocks are affected by the hydrothermal action of lava, resulting in magnetic changes. Therefore, in volcanic areas, the formation of abnormal crustal magnetic fields is not only regulated by the geomagnetic field but also directly affected by magmatic activities. In addition, the geological activities at the boundaries of tectonic plates cause the extrusion and uplift of the crust, which further triggers the formation of magnetic anomalies. Such geological tectonic activities not only change the characteristics of the abnormal crustal magnetic field but also have an important impact on its spatial distribution. Therefore, geomagnetic interference in geology is characterized by locality, distortion, and abnormality, and is not a simple approximately linear distribution. In actual detection, the regional scope is usually large, and the geological composition is complex and difficult to predict. The applicability of the first-order linear model constructed with platform position information to the geological magnetic interference generated by the lithosphere drops significantly, and the compensation result is not ideal, seriously affecting the effective discrimination of target signals. Summary of the Invention

[0005] The present invention provides an airborne magnetic compensation method and system for suppressing geological magnetic interference, which can solve the technical problem that the geological magnetic interference in the actual detection area in the prior art affects the effective discrimination of target signals.

[0006] According to one aspect of the present invention, there is provided an airborne magnetic compensation method for suppressing geological magnetic interference. The airborne magnetic compensation method for suppressing geological magnetic interference includes: constructing a geological magnetic interference compensation model for the detection area using a surface spline function; linearly expanding the traditional magnetic interference model using the geological magnetic interference compensation model to establish a new airborne magnetic compensation model including the geological magnetic interference compensation model in the detection area; calibrating the detection platform by flying, using a scalar magnetometer, a vector magnetoresistor, and an airborne GPS to collect the total magnetic field, the three components of the vector magnetoresistor, longitude, latitude, and altitude information respectively, and calculating the magnetic compensation coefficient based on the total magnetic field, the three components of the vector magnetoresistor, longitude, latitude, and altitude information; in actual detection, using the new airborne magnetic compensation model, the magnetic compensation coefficient, the real-time total magnetic field of the magnetometer, the three components of the vector magnetoresistor, and the real-time position information of the detection platform to perform high-precision real-time compensation for platform maneuver magnetic interference, geomagnetic gradient magnetic interference, and geological magnetic interference.

[0007] Further, high-precision real-time compensation for platform maneuver magnetic interference, geomagnetic gradient magnetic interference, and geological magnetic interference is performed using a new aeromagnetic compensation model, magnetic compensation coefficients, the real-time total magnetic field of the magnetometer, the three components of the vector magnetoresistance, and the real-time position information of the detection platform, which specifically includes: reading the total magnetic field in real time using a scalar magnetometer; obtaining the position information of the moving platform through the airborne GPS, and constructing the magnetic field value h related to geological magnetic interference based on the position information of the moving platform s ; obtaining the three components of the vector magnetoresistance through the vector magnetoresistance, and calculating and obtaining the model function μ related to magnetic compensation according to the three components of the vector magnetoresistance i ; filtering the model function μ related to magnetic compensation i ; calculating and obtaining the total magnetic interference value B using the new aeromagnetic compensation model, magnetic compensation coefficients, the magnetic field value h related to geological magnetic interference s and the model function μ related to magnetic compensation i ; subtracting the total magnetic interference value B measured by the scalar magnetometer from the total magnetic field to obtain the compensated total magnetic field value t t

[0008] Further, the detection platform performs a calibration flight, and uses a scalar magnetometer, a vector magnetoresistance, and the airborne GPS to collect the total magnetic field, the three components of the vector magnetoresistance, longitude, latitude, and altitude information respectively. Calculating and obtaining the magnetic compensation coefficients based on the total magnetic field, the three components of the vector magnetoresistance, longitude, latitude, and altitude information specifically includes: the detection platform performs three maneuver actions of roll, pitch, and yaw for calibration flight, and uses a scalar magnetometer, a vector magnetoresistance, and the airborne GPS to collect the total magnetic field, the three components of the vector magnetoresistance, longitude, latitude, and altitude information respectively; substituting the total magnetic field, the three components of the vector magnetoresistance, longitude, latitude, and altitude information into the new aeromagnetic compensation model, and filtering the target frequency band at both ends of the new aeromagnetic compensation model using a Butterworth filter; solving the magnetic compensation coefficient a i and the compensation coefficient b for geological magnetic interference s .

[0009] Further, the detection platform performing three maneuver actions of roll, pitch, and yaw for calibration flight specifically includes: the detection platform moves from west to north, and sequentially performs multiple groups of roll maneuver actions, multiple groups of pitch maneuver actions, and multiple groups of yaw maneuver actions; the detection platform moves from north to east, and sequentially performs multiple groups of roll maneuver actions, multiple groups of pitch maneuver actions, and multiple groups of yaw maneuver actions; the detection platform moves from east to south, and sequentially performs multiple groups of roll maneuver actions, multiple groups of pitch maneuver actions, and multiple groups of yaw maneuver actions; the detection platform moves from south to west, and sequentially performs multiple groups of roll maneuver actions, multiple groups of pitch maneuver actions, and multiple groups of yaw maneuver actions

[0010] Further, the geological magnetic interference compensation model is B s =b s h​​s , where B s is the magnetic interference value calculated by the geological magnetic interference model in the detection area, b s is the geological magnetic interference compensation coefficient to be solved, h s is the magnetic field value related to geological magnetic interference fitted by the surface spline function.

[0011] Furthermore, the magnetic field value h related to geological magnetic interference fitted by the surface spline function s can be calculated according to , where W is the earth's latitude, J is the earth's longitude, c0 is the first undetermined coefficient, c1 is the second undetermined coefficient, c2 is the third undetermined coefficient, F i is the fourth undetermined coefficient, r i is the distance between the point to be fitted (J, W) and the i-th actual measurement point, ln is the logarithmic function, and ε is the curvature factor.

[0012] Furthermore, the new aviation magnetic compensation model is B t = B TLG + B s , where B t is the total magnetic interference value, B TLG is the total field of the magnetic interference generated by ferromagnetic substances in the moving platform and the magnetic interference generated by the geomagnetic gradient calculated by the traditional compensation model, B s is the magnetic interference value calculated by the geological magnetic interference model in the detection area.

[0013] Furthermore, the total field B of the magnetic interference generated by ferromagnetic substances in the moving platform and the magnetic interference generated by the geomagnetic gradient calculated by the traditional compensation model TLG is where a i is the magnetic compensation coefficient to be solved, μ i is the model function related to magnetic compensation.

[0014] Furthermore, the model function related to magnetic compensation is

[0015] where T g is the geomagnetic field, T X , T Y , T Z are the three components of the vector magnetoresistance, W is the earth's latitude, J is the earth's longitude, and G is the height at which the platform is currently located.

[0016] According to another aspect of the present invention, an aviation magnetic compensation system for suppressing geological magnetic interference is provided. The aviation magnetic compensation system for suppressing geological magnetic interference uses the aviation magnetic compensation method for suppressing geological magnetic interference as described above for aviation magnetic compensation.

[0017] Applying the technical solution of the present invention, an airborne magnetic compensation method for suppressing geological magnetic interference is provided. Based on the traditional magnetic compensation model, this method models the geological magnetic interference in the detection area using a surface spline function. This model consists of constant coefficients, the position information of the detection platform, and curvature factors. Then, it is combined with the traditional magnetic compensation model to form a new non-linear compensation model with superior performance. During the calibration flight, relevant compensation coefficients are obtained through linear regression. Then, during actual detection, by combining these coefficients with the compensation model, platform maneuver magnetic interference, geomagnetic gradient magnetic interference, and geological magnetic interference can be removed in real time, achieving high-precision airborne magnetic compensation. Therefore, compared with the prior art, the airborne magnetic compensation method for suppressing geological magnetic interference provided by the present invention can effectively solve the influence brought by geological magnetic interference in the actual detection area, improve the compensation accuracy of the airborne magnetic compensation algorithm, and thus enhance the detection performance of airborne magnetic detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings included are used to provide a further understanding of the embodiments of the present invention, and they form a part of the specification, used to illustrate the embodiments of the present invention, and together with the text description to explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It shows a flowchart of calculating magnetic compensation coefficients during calibration provided according to a specific embodiment of the present invention;

[0020] Figure 2 It shows a schematic diagram of the maneuvering actions of the calibration-type platform movement provided according to a specific embodiment of the present invention;

[0021] Figure 3 It shows a flowchart of the real-time airborne magnetic compensation process provided according to a specific embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way restrictive of the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0024] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that for the convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0025] As Figures 1 to 3 shown, according to a specific embodiment of the present invention, an airborne magnetic compensation method for suppressing geological magnetic interference is provided. The airborne magnetic compensation method for suppressing geological magnetic interference includes: constructing a geological magnetic interference compensation model for the detection area using a surface spline function; linearly expanding the traditional magnetic interference model using the geological magnetic interference compensation model to establish a new airborne magnetic compensation model including the geological magnetic interference compensation model in the detection area; calibrating the flight of the detection platform, using a scalar magnetometer, a vector magnetoresistor, and an airborne GPS to collect the total magnetic field, the three components of the vector magnetoresistor, longitude, latitude, and altitude information respectively, and calculating and obtaining magnetic compensation coefficients based on the total magnetic field, the three components of the vector magnetoresistor, longitude, latitude, and altitude information; in actual detection, using the new airborne magnetic compensation model, the magnetic compensation coefficients, the real-time total magnetic field of the magnetometer, the three components of the vector magnetoresistor, and the real-time position information of the detection platform to perform high-precision real-time compensation for the platform maneuver magnetic interference, geomagnetic gradient magnetic interference, and geological magnetic interference.

[0026] Using this configuration method, an airborne magnetic compensation method for suppressing geological magnetic interference is provided. Based on the traditional magnetic compensation model, this method models the geological magnetic interference in the detection area using a surface spline function. This model consists of constant coefficients, the position information of the detection platform, and curvature factors. Then, it is combined with the traditional magnetic compensation model to form a new non-linear compensation model with excellent performance. During the calibration flight, relevant compensation coefficients are obtained through linear regression. Then, during actual detection, by combining these coefficients with the compensation model, platform maneuver magnetic interference, geomagnetic gradient magnetic interference, and geological magnetic interference can be removed in real time, achieving high-precision airborne magnetic compensation. Therefore, compared with the prior art, the airborne magnetic compensation method for suppressing geological magnetic interference provided by the present invention can effectively solve the influence brought by geological magnetic interference in the actual detection area, improve the compensation accuracy of the airborne magnetic compensation algorithm, and thus enhance the detection performance of airborne magnetic detection.

[0027] Specifically, in the present invention, in order to achieve airborne magnetic compensation for suppressing geological magnetic interference, it is first necessary to use a surface spline function to construct a geological magnetic interference compensation model for the detection area. In the present invention, the geological magnetic interference compensation model is B s =b s h s , where B s is the magnetic interference value calculated by the geological magnetic interference model in the detection area, b s is the geological magnetic interference compensation coefficient to be solved, and h s is the magnetic field value related to geological magnetic interference fitted by the surface spline function.

[0028] The magnetic field value h s related to geological magnetic interference fitted by the surface spline function can be calculated according to , where W is the earth's latitude, J is the earth's longitude, c0 is the first undetermined coefficient, c1 is the second undetermined coefficient, c2 is the third undetermined coefficient, F i is the fourth undetermined coefficient, r i is the distance between the point to be fitted (J, W) and the i-th actual measurement point, and ε is the curvature factor.

[0029] c0, c1, c2, and F i are undetermined coefficients, which can be solved by substituting multiple actual measurement points into the above two formulas according to the constraint conditions and .

[0030] After establishing the geological magnetic interference compensation model, the traditional magnetic interference model can be linearly extended using the geological magnetic interference compensation model to establish a new airborne magnetic compensation model including the geological magnetic interference compensation model in the detection area. In the present invention, the new airborne magnetic compensation model is B t =B TLG +Bs , where B t is the total magnetic interference value, and B TLG is the total field of the magnetic interference generated by ferromagnetic substances in the moving platform and the magnetic interference generated by the geomagnetic gradient calculated by the traditional compensation model, and B s is the magnetic interference value calculated by the geological magnetic interference model in the detection area.

[0031] The total field B of the magnetic interference generated by ferromagnetic substances in the moving platform and the magnetic interference generated by the geomagnetic gradient calculated by the traditional compensation model TLG is where a i is the magnetic compensation coefficient to be solved, and μ i is the model function related to magnetic compensation.

[0032] In the present invention, the model function related to magnetic compensation is

[0033] where T g is the geomagnetic field, T X , T Y , T Z are the three components of the vector magnetoresistance, W is the earth's latitude, J is the earth's longitude, and G is the altitude at which the platform is located at the current moment.

[0034] Furthermore, after establishing a new airborne magnetic compensation model including the geological magnetic interference compensation model in the detection area, the detection platform performs a calibration flight, and uses a scalar magnetometer, a vector magnetoresistance, and an airborne GPS to collect the total magnetic field, the three components of the vector magnetoresistance, longitude, latitude, and altitude information respectively, and calculates and obtains the magnetic compensation coefficient based on the total magnetic field, the three components of the vector magnetoresistance, longitude, latitude, and altitude information.

[0035] Specifically, in the present invention, the detection platform performs a calibration flight, and uses a scalar magnetometer, a vector magnetoresistance, and an airborne GPS to collect the total magnetic field, the three components of the vector magnetoresistance, longitude, latitude, and altitude information respectively. Calculating and obtaining the magnetic compensation coefficient based on the total magnetic field, the three components of the vector magnetoresistance, longitude, latitude, and altitude information specifically includes: the detection platform performs three maneuvering actions of roll, pitch, and yaw for calibration flight, and uses a scalar magnetometer, a vector magnetoresistance, and an airborne GPS to collect the total magnetic field, the three components of the vector magnetoresistance, longitude, latitude, and altitude information respectively; substituting the total magnetic field, the three components of the vector magnetoresistance, longitude, latitude, and altitude information into the new airborne magnetic compensation model, and filtering the target frequency band at both ends of the new airborne magnetic compensation model using a Butterworth filter; solving the magnetic compensation coefficient a i and the compensation coefficient b of the geological magnetic interference s .

[0036] Among them, the calibration flight of the detection platform by performing three maneuvering actions of roll, pitch, and yaw specifically includes: the detection platform moves from west to north, and successively performs multiple groups of roll maneuvering actions, multiple groups of pitch maneuvering actions, and multiple groups of yaw maneuvering actions; the detection platform moves from north to east, and successively performs multiple groups of roll maneuvering actions, multiple groups of pitch maneuvering actions, and multiple groups of yaw maneuvering actions; the detection platform moves from east to south, and successively performs multiple groups of roll maneuvering actions, multiple groups of pitch maneuvering actions, and multiple groups of yaw maneuvering actions; the detection platform moves from south to west, and successively performs multiple groups of roll maneuvering actions, multiple groups of pitch maneuvering actions, and multiple groups of yaw maneuvering actions. In this configuration mode, by performing multiple groups of maneuvering actions in different directions, the equation multicollinearity can be effectively avoided, and at the same time, all directions and attitudes of the aircraft during flight are traversed.

[0037] As a specific embodiment of the present invention, as Figure 2 shown, the detection platform moves from west to north, and successively performs three groups of roll maneuvering actions, three groups of pitch maneuvering actions, and three groups of yaw maneuvering actions, and the period of each group of actions is 4 to 12 seconds; the detection platform moves from north to east, and successively performs three groups of roll maneuvering actions, three groups of pitch maneuvering actions, and three groups of yaw maneuvering actions, and the period of each group of actions is 4 to 12 seconds; the detection platform moves from east to south, and successively performs three groups of roll maneuvering actions, three groups of pitch maneuvering actions, and three groups of yaw maneuvering actions, and the period of each group of actions is 4 to 12 seconds; the detection platform moves from south to west, and successively performs three groups of roll maneuvering actions, three groups of pitch maneuvering actions, and three groups of yaw maneuvering actions, and the period of each group of actions is 4 to 12 seconds.

[0038] Furthermore, after obtaining the magnetic compensation coefficient, in actual detection, the new aviation magnetic compensation model, the magnetic compensation coefficient, the real-time total magnetic field of the magnetometer, the three components of the vector magnetoresistance, and the real-time position information of the detection platform are used to perform high-precision real-time compensation for the platform maneuvering magnetic interference, the geomagnetic gradient magnetic interference, and the geological magnetic interference.

[0039] In the present invention, using the new aviation magnetic compensation model, the magnetic compensation coefficient, the real-time total magnetic field of the magnetometer, the three components of the vector magnetoresistance, and the real-time position information of the detection platform to perform high-precision real-time compensation for the platform maneuvering magnetic interference, the geomagnetic gradient magnetic interference, and the geological magnetic interference specifically includes: using a scalar magnetometer to read the total magnetic field in real time; obtaining the position information of the moving platform through the airborne GPS, and constructing the magnetic field value h related to the geological magnetic interference based on the position information of the moving platform s ; obtaining the three components of the vector magnetoresistance through the vector magnetoresistance, and calculating and obtaining the model function μ related to magnetic compensation according to the three components of the vector magnetoresistance i , and filtering the model function μ related to magnetic compensation i ; using the new aviation magnetic compensation model, the magnetic compensation coefficient, the magnetic field value h related to the geological magnetic interference s and the model function μ related to magnetic compensation iCalculate to obtain the total magnetic interference value B t ; Subtract the total magnetic interference value B from the total magnetic field measured by the scalar magnetometer t to obtain the compensated total magnetic field value

[0040] According to another aspect of the present invention, there is provided an airborne magnetic compensation system for suppressing geological magnetic interference, and this airborne magnetic compensation system for suppressing geological magnetic interference uses the airborne magnetic compensation method for suppressing geological magnetic interference as described above for airborne magnetic compensation

[0041] Applying this configuration method, there is provided an airborne magnetic compensation system for suppressing geological magnetic interference. Based on the traditional magnetic compensation model, for the geological magnetic interference in the detection area, a surface spline function is used for modeling. This model consists of constant coefficients, the position information of the detection platform, and curvature factors, and then it is combined with the traditional magnetic compensation model to form a new non-linear compensation model with excellent performance. During the calibration flight, the relevant compensation coefficients are obtained through linear regression, and then in actual detection, by combining these coefficients with the compensation model, the platform maneuver magnetic interference, geomagnetic gradient magnetic interference, and geological magnetic interference can be removed in real time, achieving high-precision airborne magnetic compensation. Therefore, compared with the prior art, the airborne magnetic compensation system for suppressing geological magnetic interference provided by the present invention can effectively solve the influence brought by geological magnetic interference in the actual detection area, improve the compensation accuracy of the airborne magnetic compensation algorithm, and thus improve the detection performance of airborne magnetic detection

[0042] For a further understanding of the present invention, the following will be combined with Figures 1 to 3 to elaborate in detail on the airborne magnetic compensation method for suppressing geological magnetic interference provided by the present invention

[0043] As Figures 1 to 3 shown, in order to overcome the influence brought by geological magnetic interference in the actual detection area in the prior art, it is urgently necessary to introduce an airborne magnetic compensation algorithm with more excellent performance, deeply model the geological magnetic interference, and expand the existing compensation model into a non-linear compensation model with higher precision, so as to more accurately and comprehensively consider the influence of different types of magnetic interference on the detection results

[0044] According to a specific embodiment of the present invention, there is provided an airborne magnetic compensation method for suppressing geological magnetic interference. This method establishes a new airborne magnetic compensation model including a geological magnetic interference compensation model, and performs real-time airborne magnetic interference compensation according to the total magnetic field obtained by the surface spline function, scalar magnetometer, the position information of the detection platform, and the three components of the vector magnetoresistance, and can simultaneously compensate for the platform maneuver magnetic interference, geomagnetic gradient interference, and geological magnetic interference; it includes the following steps

[0045] 1) Establish a geological magnetic interference compensation model, expressed as

[0046] B s =bs h s

[0047] where B s is the magnetic interference value calculated by the geological magnetic interference model in the detection area, b s is the geological magnetic interference compensation coefficient to be solved, h s is the magnetic field value related to the geological magnetic interference fitted by the surface spline function, expressed as:

[0048]

[0049] where W is the Earth's latitude, J is the Earth's longitude, r i is the distance between the point to be fitted (J, W) and the i-th actual measurement point, and they have r i 2 =(J - J i ) 2 +(W - W i ) 2 relationship, ln is the logarithmic function, J i is the abscissa of the i-th actual measurement point, W i is the ordinate of the i-th actual measurement point, ε is the curvature factor, which controls the maximum difference between the surface fitting value and the original value, and its value is generally in the range of 10 -6 to 10 -4 range. c0, c1, c2 and F i are undetermined coefficients, which can be solved through the following constraints and the above formula

[0050]

[0051] where N is the number of measurement points.

[0052] 2) Establish a new airborne magnetic compensation model including the geological magnetic interference compensation model in the detection area, which is hereinafter referred to as the total model for short, and is expressed as:

[0053] B t = B TLG + B s

[0054] where, B t is the total magnetic interference value, B TLG is the total field of the magnetic interference generated by ferromagnetic substances in the moving platform and the magnetic interference generated by the geomagnetic gradient calculated by the traditional compensation model, and is expressed as:

[0055]

[0056] where, a i is the magnetic compensation coefficient to be solved, μ iThe model function related to magnetic compensation is expressed as:

[0057] μ1 = cosα X , μ2 = cosα Y , μ3 = cosα Z ,

[0058] μ4 = T g cosα X cosα X , μ5 = T g cosα X cosα Y , μ6 = T g cosα X cosα Z ,

[0059] μ7 = T g cosα Y cosα Y , μ8 = T g cosα Y cosα Z ,

[0060] μ9 = T g cosα X (cosα X )', μ 10 = T g cosα X (cosα Y )', μ 11 = T g cosα X (cosα Z )',

[0061] μ 12 = T g cosα Y (cosα X )', μ 13 = T g cosα Y (cosα Y )', μ 14 = T g cosα Y (cosα Z )',

[0062] μ 15 = T g cosα Z (cosα X )', μ 16 = T g cosα Z(cosα Y )',

[0063] μ 17 =W, μ 18 =J, μ 19 =G

[0064] where T g represents the geomagnetic field, which can be obtained by low-pass filtering the measured total magnetic field. (cosα X )', (cosα Y )', (cosα Z )' represent the differentials of cosα X , cosα Y , cosα Z respectively. The angles between the geomagnetic field and the three axes of the moving platform coordinate system are denoted as α X , α Y , α Z , and their cosine values are expressed as:

[0065]

[0066] where T X , T Y , T Z are the three components of the vector magnetoresistance; G is the height at which the platform is currently located.

[0067] 3) The platform performs a calibration flight to obtain the magnetic compensation coefficients a i , b s ; Figure 1 The following shows the process of calculating the magnetic compensation coefficients during the calibration flight of the present invention, and the specific operations are as follows:

[0068] 3A. The moving platform performs three maneuvering actions to obtain all the required data information. The maneuvering actions are roll, pitch, and yaw, and the peak-to-peak angles are 10°, 5°, and 5° respectively. Each maneuvering action has 3 groups, and each group has a period of 4 - 12 seconds. As Figure 2 shown, this can avoid equation multicollinearity and simultaneously traverse all directions and attitudes of the aircraft during flight.

[0069] 3B. Use the obtained data to construct a new model, and filter the two ends of the new model with a Butterworth filter for the target frequency band;

[0070] 3C. Solve the magnetic compensation coefficient a i and the compensation coefficient b s for the geomagnetic interference of the filtered new model by the method of linear regression. When solving the magnetic compensation coefficient a i and the compensation coefficient b s for the geomagnetic interference, the total magnetic interference value Bt It can be obtained by measuring with a scalar magnetometer in a target - free environment.

[0071] 4) After that, when the moving platform conducts magnetic detection, the magnetic compensation coefficients a i , b s and μ obtained from the fluxgate magnetometer i (model function related to magnetic compensation) and h s (magnetic field value related to geological magnetic interference) can be used to calculate the total magnetic interference value brought by the magnetic interference of the moving platform, the geomagnetic gradient magnetic interference and the geological magnetic interference. Removing the total magnetic interference value from the detection magnetometer can obtain the compensated total magnetic field value. Figure 3 The real - time compensation process flow of the algorithm of the present invention is shown as follows, and the specific operations are as follows:

[0072] 4A. The detection magnetometer reads the total magnetic field in real time;

[0073] 4B. Obtain the position information of the moving platform through GPS, that is, longitude, latitude and altitude, and construct h s ;

[0074] 4C. Obtain the three perpendicular components T X , T Y , T Z of the magnetic field through the vector magnetoresistance. Through the above formula, calculate μ i (model function related to magnetic compensation), and filter the model function related to magnetic compensation using the same band - pass filter (i.e., the Butterworth filter in 3B);

[0075] 4D. Utilize a new airborne magnetic compensation model including the current magnetic interference compensation model in the moving platform. The magnetic compensation coefficient a i solved in step 3C and the compensation coefficient b s of the geological magnetic interference, μ i (model function related to magnetic compensation) solved in step 4C, h s (magnetic field value related to geological magnetic interference) solved in step 4B, and use the formula to calculate B t .

[0076] 4F. Subtract B t obtained in step 4E from the total magnetic field obtained in step 4A to obtain the compensated total magnetic field value.

[0077] Through the above steps, a new airborne magnetic compensation model including the geological magnetic interference compensation model of the detection area can be realized.

[0078] In summary, the present invention provides an airborne magnetic compensation method for suppressing geological magnetic interference. Based on the traditional magnetic compensation model, this method models the geological magnetic interference in the detection area using a surface spline function. This model consists of constant coefficients, the position information of the detection platform, and curvature factors. Then, it is combined with the traditional magnetic compensation model to form a new non-linear compensation model with superior performance. During the calibration flight, relevant compensation coefficients are obtained through linear regression. Then, in actual detection, by combining these coefficients with the compensation model, the platform maneuver magnetic interference, geomagnetic gradient magnetic interference, and geological magnetic interference can be removed in real time, achieving high-precision airborne magnetic compensation. Therefore, compared with the prior art, the airborne magnetic compensation method for suppressing geological magnetic interference provided by the present invention can simultaneously compensate for geological, geomagnetic gradient magnetic interference, and the maneuver magnetic interference of the moving platform, and can further improve the airborne magnetic detection ability.

[0079] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "upper" etc. can be used here to describe the spatial position relationship between one device or feature and other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figure is inverted, the device described as "above" or "over" other devices or structures will then be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used here.

[0080] In addition, it should be noted that using terms such as "first", "second" to limit components is only for the convenience of differentiating the corresponding components. Without additional statements, the above terms have no special meanings, and thus should not be construed as limiting the protection scope of the present invention.

[0081] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An airborne magnetic compensation method for suppressing geological magnetic interference, characterized in that, The aviation magnetic compensation method for suppressing geological magnetic interference includes: Constructing a geological magnetic interference compensation model for the detection area by using a surface spline function; Linearly expanding the traditional magnetic interference model by using the geological magnetic interference compensation model, and establishing a new aviation magnetic compensation model including the geological magnetic interference compensation model in the detection area; The detection platform conducts a calibration flight, and uses a scalar magnetometer, a vector magnetoresistance, and an airborne GPS to collect the total magnetic field, three components of the vector magnetoresistance, longitude, latitude, and altitude information respectively. Based on the total magnetic field, three components of the vector magnetoresistance, longitude, latitude, and altitude information, magnetic compensation coefficients are calculated; During actual detection, the new aviation magnetic compensation model, the magnetic compensation coefficients, the real-time total magnetic field of the magnetometer, three components of the vector magnetoresistance, and the real-time position information of the detection platform are used to perform high-precision real-time compensation for platform maneuver magnetic interference, geomagnetic gradient magnetic interference, and geological magnetic interference.

2. The airborne magnetic compensation method for suppressing geological magnetic interference according to claim 1, wherein Using the new aviation magnetic compensation model, the magnetic compensation coefficients, the real-time total magnetic field of the magnetometer, three components of the vector magnetoresistance, and the real-time position information of the detection platform to perform high-precision real-time compensation for platform maneuver magnetic interference, geomagnetic gradient magnetic interference, and geological magnetic interference specifically includes: Using a scalar magnetometer to read the total magnetic field in real time; Obtain the position information of the moving platform through the on-board GPS, and construct the magnetic field value h related to geological magnetic interference based on the position information of the moving platform s ; Obtain three components of vector magnetoresistance through vector magnetoresistance, and calculate and obtain a model function μ related to magnetic compensation according to the three components of the vector magnetoresistance i , for the model function μ related to the magnetic compensation i Perform filtering; Using the new aviation magnetic compensation model, the magnetic compensation coefficient, and the magnetic field value h related to geological magnetic interference s and the model function μ related to magnetic compensation i calculate and obtain the total magnetic interference value B t ; Subtract the total magnetic interference value B from the total magnetic field measured by the scalar magnetometer t to obtain the compensated total magnetic field value.

3. The airborne magnetic compensation method for suppressing geological magnetic interference according to claim 1, wherein, The detection platform conducts a calibration flight, and using a scalar magnetometer, a vector magnetoresistance, and an airborne GPS to collect the total magnetic field, three components of the vector magnetoresistance, longitude, latitude, and altitude information respectively. Based on the total magnetic field, three components of the vector magnetoresistance, longitude, latitude, and altitude information, calculating the magnetic compensation coefficients specifically includes: The detection platform conducts a calibration flight by performing three maneuver actions of roll, pitch, and yaw, and uses a scalar magnetometer, a vector magnetoresistance, and an airborne GPS to collect the total magnetic field, three components of the vector magnetoresistance, longitude, latitude, and altitude information respectively; Substitute the total magnetic field, three components of the vector magnetoresistance, longitude, latitude, and altitude information into the new aviation magnetic compensation model, and use a Butterworth filter to filter the target frequency band at both ends of the new aviation magnetic compensation model; Solve the magnetic compensation coefficient a by linear regression i and the compensation coefficient b for geological magnetic interference s .

4. The method for suppressing geological magnetic interference in airborne magnetic compensation according to claim 3, wherein The detection platform conducts a calibration flight by performing three maneuver actions of roll, pitch, and yaw specifically includes: The detection platform moves from west to north, and sequentially performs multiple groups of roll maneuver actions, multiple groups of pitch maneuver actions, and multiple groups of yaw maneuver actions; The detection platform moves from north to east, and sequentially performs multiple groups of roll maneuver actions, multiple groups of pitch maneuver actions, and multiple groups of yaw maneuver actions; The detection platform moves from east to south, and sequentially performs multiple groups of roll maneuver actions, multiple groups of pitch maneuver actions, and multiple groups of yaw maneuver actions; The detection platform moves from south to west, and sequentially performs multiple groups of roll maneuver actions, multiple groups of pitch maneuver actions, and multiple groups of yaw maneuver actions.

5. The method for suppressing geological magnetic interference in airborne magnetic compensation according to any one of claims 1 to 4, characterized in that, The geological magnetic interference compensation model is B s = b s h s , where B s is the magnetic interference value calculated by the geological magnetic interference model in the detection area, b s is the geological magnetic interference compensation coefficient to be solved, and h s is the magnetic field value related to the geological magnetic interference fitted by the surface spline function.

6. The airborne magnetic compensation method for suppressing geological magnetic interference according to claim 5, wherein The magnetic field value h related to geological magnetic interference fitted by a surface spline function s can be obtained according to where W is the earth's latitude, J is the earth's longitude, c0 is the first undetermined coefficient, c1 is the second undetermined coefficient, c2 is the third undetermined coefficient, F i is the fourth undetermined coefficient, r i is the distance between the point to be fitted (J, W) and the i-th actual measurement point, ln is the logarithmic function, and ε is the curvature factor.

7. The method for suppressing geological magnetic interference in airborne magnetic compensation according to claim 6, characterized in that, The new model of aviation magnetic compensation is B t = B TLG + B s , where B t is the total magnetic interference value, B TLG is the total field of the magnetic interference generated by ferromagnetic substances in the moving platform and the magnetic interference generated by the geomagnetic gradient calculated by the traditional compensation model, and B s is the magnetic interference value calculated by the geological magnetic interference model in the detection area.

8. The method for suppressing geological magnetic interference in airborne magnetic compensation according to claim 7, wherein The total field B of the magnetic interference generated by ferromagnetic substances in the moving platform and the magnetic interference generated by the geomagnetic gradient calculated by the traditional compensation model TLG is where a i is the magnetic compensation coefficient to be solved, and μ i is the model function related to magnetic compensation 9. The method for suppressing geological magnetic interference in aviation magnetic compensation according to claim 8, characterized in that The model function related to magnetic compensation is where T g is the geomagnetic field, and T X , T Y , T Z are the three components of vector magnetoresistance, W is the earth's latitude, J is the earth's longitude, and G is the altitude at the current moment of the platform.

10. An airborne magnetic compensation system for suppressing geological magnetic interference, characterized in that, The aviation magnetic compensation system for suppressing geological magnetic interference uses the aviation magnetic compensation method for suppressing geological magnetic interference as described in any one of claims 1 to 9 to perform aviation magnetic compensation.

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