CN111580023B - Full-axis magnetic gradiometer, magnetic force operation system and operation method - Google Patents

Abstract

The invention provides a full-axis magnetic gradiometer, a magnetic operation system and an operation method. The gradiometer comprises: total field magnetic force sensing unit: the device comprises a first magnetometer, a second magnetometer, a third magnetometer and a fourth magnetometer, wherein the first magnetometer and the second magnetometer are transversely arranged at intervals, and the third magnetometer and the fourth magnetometer are longitudinally arranged at intervals; the first magnetometer and the second magnetometer are used for acquiring horizontal and horizontal total field gradients, the third magnetometer and the fourth magnetometer are used for acquiring vertical and horizontal total field gradients, and the first magnetometer, the second magnetometer and the fourth magnetometer are used for acquiring horizontal and longitudinal total field gradients; a data processing system: and the magnetic force data acquisition unit is communicated with the total field magnetic force sensing unit and is used for acquiring magnetic force data detected by the total field magnetic force sensing unit. A magnetic force operating system can be constructed by using one or more of the full-axis magnetometers. The magnetic force operation method synchronously collects a plurality of total field magnetic force sensing unit data, and can calculate and obtain magnetic field gradient tensor data.

Description

Full-axis magnetic gradiometer, magnetic operation system and operation method

Technical Field

The present invention relates to the field of magnetic prospecting technology, and in particular to a full-axis magnetic gradiometer, a magnetic operation system and an operation method.

Background Art

Conventional marine magnetic detection is usually geomagnetic total field measurement, the structure is shown in Figure 1. The tail end of the survey ship 1 tows a single total field magnetometer through a tow cable 2. This operation mode uses a single total field magnetometer for towing operation, towing the magnetometer in the seawater at the stern of the ship through a tow cable, which is powered and transmits signals to obtain the magnetic parameters of the geomagnetic field. This operation mode can only obtain geomagnetic total field data, and the amount of magnetic data obtained is small. The density of horizontal measurement points (typical horizontal measurement point spacing is greater than 1000m) is much lower than the density of vertical measurement points (typical vertical measurement point spacing is less than 5m), making geological interpretation difficult and the operation efficiency low. Conventional marine magnetic measurements are seriously disturbed by solar diurnal variations. Geomagnetic diurnal variation measurements are required at the same time as marine magnetic measurements, which is difficult to achieve in the open sea, resulting in low accuracy and low measurement efficiency of conventional marine magnetic measurements.

Summary of the invention

The purpose of the present invention is to provide a full-axis magnetic gradiometer, a magnetic operation system and an operation method that can measure multiple geomagnetic data in order to solve the problem of limited measurement data in the magnetic detection system in the prior art.

In order to achieve the above object, in some embodiments of the present invention, the following technical solutions are provided:

A full-axis magnetic gradiometer, comprising:

matrix;

Total field magnetic sensing unit: installed on the substrate, including a first magnetometer and a second magnetometer arranged in a transverse interval, and a third magnetometer and a fourth magnetometer arranged in a longitudinal interval; wherein the first magnetometer and the second magnetometer are used to collect the total field gradient in the horizontal transverse direction, the third magnetometer and the fourth magnetometer are used to collect the total field gradient in the vertical direction, and the first magnetometer, the second magnetometer and the fourth magnetometer are used to collect the total field gradient in the horizontal longitudinal direction;

Three-component magnetometer: installed on the substrate, used to measure the X-axis component, Y-axis component and Z-axis component of the geomagnetic field;

Data processing system: communicates with the total field magnetic sensing unit and the three-component magnetometer to collect magnetic data detected by the total field magnetic sensing unit and the three-component magnetometer.

In some embodiments of the present invention, the gradiometer further comprises a posture sensor mounted on the substrate, and the data acquisition unit further communicates with the posture sensor to acquire posture data of the gradiometer.

In some embodiments of the present invention, the directions of the three axes of the three-component magnetometer are consistent with the directions of the three axes of the attitude sensor.

In some embodiments of the present invention, the substrate includes: a non-magnetic counterweight frame, a buoyancy material arranged on the frame, and the data processing system, the total magnetic field sensing unit, and the three-component magnetometer are arranged on the buoyancy material.

In some embodiments of the present invention, it further comprises a first frame and a second frame mounted on the buoyancy material;

The first magnetometer and the second magnetometer are installed on the first frame at intervals and arranged on both sides of the buoyancy material;

The third magnetometer and the fourth magnetometer are installed on the second frame and arranged up and down.

In some embodiments of the present invention, the gradiometer further includes a power supply for supplying power to the magnetometer, the magnetometer and the data processing system; the base further includes a sealed cabin, and the power supply is arranged in the sealed cabin.

In some embodiments of the present invention, the data processing system is configured to calculate magnetic field gradient tensor data based on detection data of the total field magnetic sensing unit and the three-component magnetometer.

In some embodiments of the present invention, a magnetic operation system is also provided, comprising the above-mentioned full-axis magnetic gradiometer and a data terminal, wherein the data terminal is located on a survey ship, the full-axis magnetic gradiometer comprises a wireless transmission module, and the data terminal comprises a wireless receiving module, and the data terminal can perform wireless data communication with each full-axis magnetic gradiometer.

In some embodiments of the present invention, if the operating system includes multiple full-axis magnetic gradiometers, the multiple full-axis magnetic gradiometers are arranged in an array; the data processing system of a gradiometer is set as a master node, and the data processing systems of other gradiometers except the master node are slave nodes, the slave nodes wirelessly communicate with the master node, and the master node wirelessly communicates with the data terminal. During magnetic operation, a survey ship synchronously tows multiple full-axis magnetic gradiometers, and the multiple full-axis magnetic gradiometers are arranged in an array. The data processing system of a gradiometer is set as a master node, and the data processing systems of other gradiometers except the master node are slave nodes, and multiple towed magnetometers are towed in a self-organizing network, the slave nodes wirelessly communicate with the master node, and the master node wirelessly communicates with the survey ship data terminal.

In some embodiments of the present invention, a magnetic operation method is also provided, using the above-mentioned magnetic operation system, comprising:

Synchronously collect data from multiple total field magnetic sensing units, perform shaping processing on the data, generate a standard square wave signal, use digital interpolation to calculate the frequency of the square wave signal, and solve the magnetic field value;

Collect the three-component geomagnetic data, combine it with the attitude sensor data, and calculate it into the geodetic coordinate system;

The magnetic field gradient tensor data is calculated based on the detection data of the total field magnetic sensing unit and the three-component magnetometer.

Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

The full-axis magnetic gradiometer can simultaneously detect total magnetic field data and geomagnetic three-component data, and can calculate magnetic field gradient tensor data. Compared with the existing technology, it improves the system function, detection efficiency and information volume. The detection system constructed with the full-axis magnetic gradiometer can simultaneously tow multiple magnetic gradiometer tow bodies for magnetic detection. The self-organizing network data of multiple towed magnetometer tow bodies are synchronously collected and transmitted, which greatly improves the lateral data density of magnetic measurement and can improve the accuracy of magnetic detection.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG1 is a schematic diagram of a magnetic detection structure in the prior art;

FIG2 is a schematic structural diagram of a full-axis magnetic gradiometer according to the present invention;

FIG3 is a schematic diagram of the top view of the structure of the full-axis magnetic gradiometer of the present invention;

FIG4 is a schematic diagram of wireless data transmission of a magnetic detection system according to the present invention;

FIG5 is a schematic diagram of the logical structure of the magnetic detection system of the present invention;

FIG6 is a schematic diagram of the logical structure of a data processing system;

FIG7 is a schematic diagram of the logical structure of a data terminal;

Figure 8 is a schematic diagram of the structure of the ocean detection system;

1- Survey vessel;

2-tow cable;

3- Magnetometer;

401-non-magnetic counterweight frame, 4011-drag point, 402-buoyancy material, 403-sealed cabin, 404-first frame, 405-second frame;

501-first magnetometer, 502-second magnetometer, 503-third magnetometer, 504-fourth magnetometer,

6- Three-component magnetometer;

7- Data processing system;

8- attitude sensor;

9-GPS module;

10- Power supply;

1101-master node magnetometer, 1102-slave node magnetometer;

12-Earthquake source.

DETAILED DESCRIPTION

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

It should be noted that the terms "first" and "second" are only used for descriptive purposes and do not imply relative importance. "Connected" and "communicating" may refer to direct connection and direct communication between components, or indirect connection and indirect communication between components.

A full-axis magnetic gradiometer is used for magnetic detection operations. The magnetic gradiometer provides total geomagnetic field data and full-axis magnetic gradient data, and the measurement data information is richer. The structure of the magnetic gradiometer refers to Figures 2 and 3, including:

Substrate; in some embodiments, the substrate includes: a non-magnetic counterweight frame 401, a buoyancy material 402 arranged on the non-magnetic counterweight frame 401, and a front end of the frame 401 is provided.

Total field magnetic sensing unit: installed on the substrate, specifically installed on the buoyancy material 402, including a first magnetometer 501 and a second magnetometer 502 arranged in a transverse interval, and a third magnetometer 503 and a fourth magnetometer 504 arranged in a longitudinal interval; wherein the first magnetometer 501 and the second magnetometer 502 are used to collect the total field gradient in the horizontal transverse direction, the third magnetometer 503 and the fourth magnetometer 504 are used to collect the total field gradient in the vertical direction, and the first magnetometer 501, the second magnetometer 502 and the fourth magnetometer 504 are used to collect the total field gradient in the horizontal longitudinal direction; preferably, the four magnetometers are CS-3 high-precision cesium optical pump magnetometers produced by Canadian Scintrex Company;

Three-component magnetometer 6: installed on the substrate, specifically installed on the buoyancy material 402, for measuring the X-axis component, Y-axis component and Z-axis component of the geomagnetic field;

Data processing system 7: includes a data acquisition unit, specifically a total field magnetic data acquisition module and a three-component magnetometer data acquisition module, which communicate with the total field magnetic sensing unit and the three-component magnetometer 6 respectively to collect magnetic data detected by the total field magnetic sensing unit and the three-component magnetometer 6. The data processing system 7 includes a main controller for data processing and calculation.

Please refer to Figures 2 and 3 for further details.

The total field magnetic sensing unit includes four fixedly mounted magnetic sensors for measuring total magnetic field data and full-axis magnetic gradient data. The first frame 404 and the second frame 405 on the buoyancy material 402; the first magnetometer 501 and the second magnetometer 502 are installed on the first frame 404 at intervals, arranged on both sides of the buoyancy material 402, for measuring the vertical total field gradient; the third magnetometer 503 and the fourth magnetometer 504 are installed on the second frame 405, arranged up and down, for measuring the lateral total magnetic field gradient. The first magnetometer 501, the second magnetometer 502 and the fourth magnetometer 504 cooperate to measure the longitudinal aeromagnetic total field gradient. In the attached figure, dx, dy, and dz are the horizontal horizontal, horizontal longitudinal, and vertical baseline lengths, respectively.

Furthermore, the total field magnetic sensing unit is used to receive the main controller command in real time, synchronously collect the magnetic data of the four total field magnetometers and send the data to the main controller for processing. The total field magnetometer acquisition module first shapes the Larmor signal output by the magnetometer into a standard square wave signal, and then uses a digital interpolation method to collect and calculate the frequency of the square wave signal, and then calculates the corresponding magnetic field value, thereby ensuring the synchronous collection of data from each magnetometer. Preferably, the shaping module uses a 74HC14 Schmitt trigger.

The digital interpolation method is a further improvement to the problem that the gate time of the equal-precision frequency measurement method is not fixed, resulting in the inability to completely synchronize the frequency of the Larmor signals output by the magnetometer probes. When the main controller issues an acquisition instruction, the gate time is generated by the standard pulse signal inside the chip, and the measured signal and the standard signal are counted simultaneously. The measured signal frequency can be expressed as:

f _x =[(t ₂ -t ₁ +t ₃ )/t ₂ +n]/T (1)

The corresponding error expression is:

σ＝(2f _x f _G )/f _s (2)

Where _fx is the measured signal frequency, _fG is the sampling frequency, and _fs is the system standard pulse frequency. It can be seen that when the measured signal range and sampling rate are constant, the error can be reduced by appropriately increasing the standard pulse signal frequency. Although this method still has an error of ±1 of the standard signal, the time interval output can be stabilized due to the fixed gate time. When the signal acquisition channels of the four total field magnetometers use the same sampling control signal and gate time, synchronous acquisition between multiple channels can be achieved.

The three-component magnetometer 6 is a fluxgate magnetic sensor used to measure the three components of the earth's magnetic field X, Y, and Z. In some embodiments of the present invention, the gradiometer further includes a posture sensor installed on the substrate, and the data acquisition unit further communicates with the posture sensor 8 to collect posture data of the gradiometer. Furthermore, the three-component magnetometer 6 should be placed horizontally on the buoyancy material 402, and the placement position should be as close to the posture sensor 8 as possible to avoid other noise interference. The three-axis direction of the three-component magnetometer 6 should be consistent with the three-axis direction of the posture sensor 8.

Furthermore, in the data processing system, the acquisition module responsible for the data of the three-component magnetometer 6 includes an AD acquisition chip. When the main controller issues an acquisition instruction, the three-component magnetometer acquisition module acquires the three-axis linear analog voltage of the X-axis, Y-axis, and Z-axis output by the three-component magnetometer 6 and converts it into a digital signal and transmits it to the main controller for processing. Preferably, the AD acquisition chip uses the AD7791 chip of ADI Company, and the 24-bit high resolution and low power consumption characteristics can meet the operation needs.

Furthermore, the full-axis magnetic gradiometer also includes the following functional units.

GPS module 9: It is set on the buoyancy material and communicates with the main controller. It is used to receive the satellite 1pps timing signal and NEMA information, send it to the main controller, and provide a high-precision timing clock to the main controller. During operation, the GPS timing pulse signal is used as the reference clock to trigger the collection of each module. The main controller controls other collection modules to strictly carry out synchronous data collection of the total field magnetic sensor unit, the three-component magnetometer 6, the attitude sensor 8 and other units.

Power supply 10: used to supply power to the power-consuming equipment such as the magnetometer, magnetometer and data processing system; in order to solve the problem of placing the power supply 10, the base further includes a sealed cabin 403, and the power supply is arranged in the sealed cabin 403. The sealed cabin 430 can be arranged on the buoyancy material 402, or inside the buoyancy material 402. The data processing system includes a power management module, which is used to perform DC-DC step-down processing on the power supply in the sealed cabin 403 and provide stable power to each power-consuming module.

Data terminal: can be set up in a remote room or on a ship to monitor the data collected and calculated by the full-axis magnetic gradiometer. It is equipped with a wireless receiving module, a data storage module and a data display module. The data terminal parses and processes the data packets sent by the wireless module, and parses the data into the towed body number, total magnetic field data, magnetic gradient data, three-component magnetic data, attitude data, position data, time information, and sends it to the display module and storage module in the above data format. The display module is used to display the parsed data for real-time monitoring. The storage module is used to record the parsed data in real time for subsequent solution. Preferably, the storage module is an SD card (including an SD card management module) or a hard disk.

Wireless transmission module: configured in the data processing system to solve the data communication problem between full-axis magnetic gradiometers and between full-axis magnetic gradiometers and control terminals. The wireless transmission module is mainly used to wirelessly transmit the data packets collected and packaged by the main controller multiple times. Each data packet contains the total field magnetic sensor unit data, three-component magnetic data, attitude data, GPS positioning data, time information and the unique number of the corresponding magnetometer tow body. If the detection system is equipped with multiple full-axis magnetic gradiometers, each full-axis magnetic gradiometer tow body contains a data processing system, and each data processing system contains a wireless transmission module, which can be configured in the following form.

Example 1: When the detection system is configured with a full-axis magnetic gradiometer to perform full-axis magnetic gradient measurement, the wireless module should be configured to normal data transmission mode, that is, point-to-point data transmission, and the sending address should be the same as the wireless receiving module address of the data terminal, and after the communication rate, working frequency band, transceiver channel and other parameters are configured, the wireless transmission of single-packet data can be realized. Preferably, the wireless transmission module is selected as Siwei's LoRa6500pro, which has a maximum transmission distance of 10KM and a receiving sensitivity of -139dBm, so that the LoRa demodulation technology can still correctly demodulate data under noise, and has high anti-interference ability to meet the needs of the operation.

Embodiment 2: Referring to FIG4, when the detection system is configured with multiple full-axis magnetic gradiometers for full-axis magnetic gradient measurement, considering that the distance between the data terminal and the full-axis magnetic gradiometer is relatively far, if each data terminal transmits data to the measurement ship, on the one hand, it will increase the power consumption, and on the other hand, it cannot be guaranteed that the data terminal accurately receives the data of all floating bodies. Therefore, when the measurement ship tows multiple full-axis magnetic gradiometers for operation, each full-axis magnetic gradiometer communicates in a network, preferably using the ZigBee protocol, and the mode configuration is "one-to-many mode". ", that is, one master and multiple slaves mode, the networking module located in the middle full-axis magnetic gradiometer is set as the master node magnetometer 1101, and the networking modules on the other full-axis magnetic gradiometers are slave node magnetometers 1102. The serial port data received by the master node magnetometer 1101 can be transmitted to the serial port outputs of all other slave node magnetometers 1102, and the serial port data received by other slave node magnetometers 1102 are transmitted separately to the master node magnetometer 1101, so as to realize the data collection and control of the master node magnetometer 1101 on the other slave node magnetometers 1102.

Both the master node and the slave node have an automatic relay function, and each node forms a network. When the node signal cannot be directly reached, the data can also be automatically relayed to the master node. The master node collects the data transmitted from other nodes and outputs it to the main controller through the serial port for integration. Since the distance between the master node and the data terminal is several kilometers, preferably, after the master node receives the data from other nodes, the integrated data packet is transmitted point-to-point to the indoor acquisition system of the gradiometer through the LoRa6500pro communication module described in Example 1. In actual operation, the distance between two adjacent full-axis magnetic gradiometers is about 100m. Preferably, the ZigBee networking module in the wireless module on each full-axis magnetic gradiometer uses TI's high-performance and low-power 2.4G radio frequency transceiver core CC2530. The transmission distance of this chip in open areas can reach 200m, and the air rate is as high as 250Kbps. Meet the needs of networking communication transmission. (The wireless module of the above-mentioned master node includes a wireless transmission module and a networking module, and the wireless module of the slave node only has a networking module)

In the above implementation, the data terminal and the master node magnetometer 1101 have the same wireless transmission module model, preferably, both use LoRa6500pro communication module. The address of the wireless receiving module in the ship is the same as the target address of the floating body sending module, and other parameters can be the same. Then, the data packet sent by the floating body master node is received directionally, and the data packet is sent to the data processing module through the serial port.

In some embodiments of the present invention, the data processing system is configured to calculate magnetic field gradient tensor data based on detection data of the total field magnetic sensing unit and the three-component magnetometer.

The specific calculation method is as follows.

Wherein, G is the full-axis magnetic gradient, _Gx is the full-axis magnetic gradient component in the X-axis, _Gy is the full-axis magnetic gradient component in the Y-axis, and _Gz is the full-axis magnetic gradient component in the Z-axis. _{T h1} is the total magnetic field strength measured by the first magnetometer 501, T _h2 is the total magnetic field strength measured by the second magnetometer 502, T _v1 is the total magnetic field strength measured by the third magnetometer 503, and T _v2 is the total magnetic field strength measured by the fourth magnetometer 504. d _x is the horizontal transverse baseline length, _dy is the horizontal longitudinal baseline length, and d _z is the vertical baseline length.

The magnetic field gradient tensor g represents the spatial change rate of the three components (Bx, By, Bz) of the magnetic field vector along three mutually orthogonal coordinate axes. The magnetic field gradient tensor g contains a total of 9 components, as shown in Formula 5.

Among them, g _xx is the gradient of Bx along the x direction, g _xy is the gradient of Bx along the y direction, g _xz is the gradient of Bx along the z direction, g _yx is the gradient of By along the x direction, g _yy is the gradient of By along the y direction, g _yz is the gradient of By along the z direction, g _zx is the gradient of Bz along the x direction, g _zy is the gradient of Bz along the y direction, and g _zz is the gradient of Bz along the z direction.

Wherein, _Bex is the direction cosine of the geomagnetic field direction vector along the x direction, _Bey is the direction cosine of the geomagnetic field direction vector along the y direction, _Bez is the direction cosine of the geomagnetic field direction vector along the z direction, and _kx , _ky , and _kz are frequency domain wave numbers.

In some embodiments of the present invention, based on the full-axis magnetic gradiometer, a magnetic detection system is further provided. The magnetic detection system includes a data terminal and at least one full-axis magnetic gradiometer.

Further provided is an application of a magnetic detection system at sea.

Referring to FIG8 , a survey vessel 1 is included, and a data terminal is configured in the survey vessel 1. A seismic source 12 is provided at the stern for performing seismic detection tasks. The full-axis magnetic gradiometer is towed at the rear end of the survey vessel 1 via a towline 2 and is towed in the seawater at the tail of the towline. During the operation, the navigation speed of the survey vessel is controlled at 4-5 knots; marine seismic detection is performed simultaneously with the magnetic detection task according to the operation task.

During the operation, the main controller receives the high-precision timing pulse and GPRMC data of the GPS module. The main controller uses the high-precision timing pulse signal of GPS as the control signal to trigger the acquisition of each module. At the same time, the main controller synchronously issues acquisition instructions to each data acquisition unit. After receiving the instruction, the total field magnetometer acquisition module synchronously collects the magnetic data of the four total field magnetometers, and then collects it every 100ms and sends the data to the main controller. After receiving the instruction, the three-component magnetometer acquisition module collects the three-component magnetic data, and then collects it every 100ms and sends the data to the main controller. After receiving the instruction, the attitude module collects the attitude data of the floating body, and then collects it every 100ms and sends the data to the main controller. During the operation, the main controller will package the data collected each time into a data frame format according to the magnetometer tow body number, four total field magnetic data, three-component magnetic data, attitude data, position information, and time information, and temporarily store it in RAM. After collecting ten times, it will be sent to the wireless transmission module through the serial port, and further sent to the data terminal.

In this embodiment, five full-axis magnetic gradiometers are towed at the rear end of the survey vessel 1. The magnetic gradiometer in the middle is set as the master node gradiometer 1101, and the other four nodes are set as slave node gradiometers 1102. As a simplification of the present invention, one full-axis magnetic gradiometer can also be selected according to the survey requirements. The networking communication mode of the master node and the slave node refers to Example 1 and Example 2, and will not be repeated.

In some embodiments of the present invention, a magnetic operation method is also provided, using the above-mentioned magnetic operation system, comprising:

The data of multiple total field magnetic force sensing units are collected synchronously, the data is shaped, a standard square wave signal is generated, the frequency of the square wave signal is calculated by digital interpolation, and the magnetic field value is solved; the specific calculation method is referred to the previous embodiment and will not be repeated here;

Collect the three-component geomagnetic data, combine it with the attitude sensor data, and calculate it into the geodetic coordinate system to improve the data accuracy;

The magnetic field gradient tensor data can be further calculated based on the total field magnetic sensor unit data and the geomagnetic three-component data; the specific calculation method refers to the previous embodiment and will not be repeated here.

The full-axis magnetic gradiometer provided by the present invention is used in the detection system for three-dimensional magnetic detection, which can simultaneously detect total field magnetic data and geomagnetic three-component data, and can calculate and obtain magnetic field gradient tensor data, which improves the function of the system compared with the prior art. The detection system can simultaneously tow multiple magnetometer towing bodies for magnetic detection, and multiple towed magnetometer towing bodies self-organizing network data synchronously collect and transmit, greatly improving the lateral data density of magnetic measurement, and the lateral measurement point density reaches 100m or even higher, which can increase the lateral data density by more than 10 times compared with the prior art. Orthogonal re-measurement of the face element of magnetic data can be realized, and the number of re-measurements of all face elements can reach more than 2 times, which reduces the measurement error caused by single acquisition in traditional marine magnetic detection and improves the accuracy of magnetic measurement by more than 20%. In particular, it can be synchronized with three-dimensional seismic detection to obtain three-dimensional magnetic detection data synchronously, greatly improving the efficiency and information volume of geophysical detection.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. A full-axis magnetic gradiometer, characterized in that it comprises: matrix; Total field magnetic sensing unit: installed on the substrate, including a first magnetometer and a second magnetometer arranged in a transverse interval, and a third magnetometer and a fourth magnetometer arranged in a longitudinal interval; wherein the first magnetometer and the second magnetometer are used to collect the total field gradient in the horizontal transverse direction, the third magnetometer and the fourth magnetometer are used to collect the total field gradient in the vertical direction, and the first magnetometer, the second magnetometer and the fourth magnetometer are used to collect the total field gradient in the horizontal longitudinal direction; Three-component magnetometer: installed on the substrate, used to measure the X-axis component, Y-axis component and Z-axis component of the geomagnetic field; the data processing system further collects the magnetic data detected by the three-component magnetometer; The data processing system communicates with the total field magnetic sensing unit to collect magnetic data detected by the total field magnetic sensing unit, and calculates magnetic field gradient tensor data according to the detection data of the total field magnetic sensing unit and the three-component magnetometer; the calculation method of the magnetic field gradient tensor data includes: G = [ _Gx , _Gy , _Gz ]; Wherein, G is the full-axis magnetic gradient, _Gx is the full-axis magnetic gradient in the X-axis component, _Gu is the full-axis magnetic gradient in the Y-axis component, _Gz is the full-axis magnetic gradient in the Z-axis component; T _h1 is the total magnetic field intensity measured by the first magnetometer, T _h2 is the total magnetic field intensity measured by the second magnetometer, T _v1 is the total magnetic field intensity measured by the third magnetometer, T _v2 is the total magnetic field intensity measured by the fourth magnetometer; _dx is the horizontal transverse baseline length, _dy is the horizontal longitudinal baseline length, and _dz is the vertical baseline length. 2. The full-axis magnetic gradiometer as described in claim 1 is characterized in that the gradiometer further includes a posture sensor installed on a substrate, and the data processing system further communicates with the posture sensor to collect posture data of the gradiometer; the directions of the three axes of the three-component magnetometer are consistent with the directions of the three axes of the posture sensor. 3. The full-axis magnetic gradiometer as described in claim 1 is characterized in that the base includes: a non-magnetic counterweight frame, a buoyancy material arranged on the frame, and the data processing system, the total magnetic field sensor unit, and the three-component magnetometer are arranged on the buoyancy material. 4. The full-axis magnetic gradiometer according to claim 3, further comprising a first frame and a second frame mounted on the buoyancy material; The first magnetometer and the second magnetometer are installed on the first frame at intervals and arranged on both sides of the buoyancy material; The third magnetometer and the fourth magnetometer are installed on the second frame and arranged up and down. 5. The full-axis magnetic gradiometer as described in claim 3 is characterized in that the gradiometer further includes a power supply for supplying power to the magnetometer, magnetometer and data processing system; the base further includes a sealed cabin, and the power supply is arranged in the sealed cabin. 6. A magnetic operation system, characterized in that it comprises at least one full-axis magnetic gradiometer as described in any one of claims 1 to 5, and a data terminal, the full-axis magnetic gradiometer comprising a wireless transmitting module, the data terminal comprising a wireless receiving module, and the data terminal can perform wireless data communication with each full-axis magnetic gradiometer. 7. The magnetic operation system as described in claim 6 is characterized in that if it includes multiple full-axis magnetic gradiometers, the multiple full-axis magnetic gradiometers are distributed in an array; the data processing system of a gradiometer is set as a master node, and the data processing systems of other gradiometers except the master node are slave nodes, the slave node wirelessly communicates with the master node, and the master node wirelessly communicates with the data terminal. 8. A magnetic operation method, using the magnetic operation system according to claim 6 or 7, characterized in that it comprises: Synchronously collect data from multiple total field magnetic sensing units, perform shaping processing on the data, generate a standard square wave signal, use digital interpolation to calculate the frequency of the square wave signal, and solve the magnetic field value; Collect the three-component geomagnetic data, combine it with the attitude sensor data, and calculate it into the geodetic coordinate system; Calculate magnetic field gradient tensor data based on detection data from the total field magnetic sensing unit and the three-component magnetometer; The method for calculating the magnetic field gradient tensor data includes: G = [ _Gx , _Gy , _Gz ]; Wherein, G is the full-axis magnetic gradient, _Gx is the full-axis magnetic gradient in the X-axis component, _Gy is the full-axis magnetic gradient in the Y-axis component, _Gz is the full-axis magnetic gradient in the Z-axis component; T _h1 is the total magnetic field intensity measured by the first magnetometer, T _h2 is the total magnetic field intensity measured by the second magnetometer, T _v1 is the total magnetic field intensity measured by the third magnetometer, T _v2 is the total magnetic field intensity measured by the fourth magnetometer; _dx is the horizontal transverse baseline length, _dy is the horizontal longitudinal baseline length, and _dz is the vertical baseline length.