Scalar magnetic anomaly ground movement measurement system and magnetic map measurement method

Abstract

The invention belongs to the technical field of magnetic measurement, and particularly relates to a scalar magnetic anomaly ground movement measurement system and a standard magnetic map measurement method, and the method comprises the steps: vertically placing two scalar sensors at different heights; obtaining magnetic anomaly data after the two scalar sensors are leveled and three-dimensional position data of the corresponding measuring points; according to the elevations of the measurement data of the two scalar magnetic sensors, calculating the elevation of a calculation surface of upward continuation of the data after leveling of the lower scalar sensor; according to the upward continuation calculation surface elevation, continuating measurement data of a lower scalar sensor upwards to a calculation surface to obtain continuation magnetic anomaly data; calculating a Pearson's correlation coefficient of the continuation magnetic anomaly data and the anomaly data of the upper scalar magnetic sensor; obtaining a correlation threshold, and judging whether the Pearson's correlation coefficient is greater than or equal to the correlation threshold; if not, the continuation magnetic anomaly data is the measured magnetic map, and vibration errors caused by ground fluctuation can be effectively reduced through continuation calculation.

Description

Technical Field

[0001] This application belongs to the field of magnetic measurement technology, and in particular refers to a scalar magnetic anomaly ground movement measurement system and a standard magnetic map measurement method. Background Technology

[0002] Magnetic anomaly detection technology is an effective means of detecting magnetic targets. Due to its characteristics of being unaffected by weather and allowing for non-contact measurement, it is widely used in fields such as geological resource exploration, metal pipeline detection, and unexploded ordnance detection. Ground-based magnetic anomaly measurement uses mobile platforms to carry magnetic measuring equipment, offering low cost and high precision, and is a common form of magnetic anomaly measurement.

[0003] However, due to the limitations of the field environment, the measurement system inevitably introduces vibration errors caused by ground undulations during movement, thus reducing the accuracy of magnetic measurements. On the other hand, when a magnetic target is present, the magnetic anomaly signal generated by the target decays cubically with the distance from the target to the measurement point. Even small changes in measurement height will affect the accuracy of the magnetic map and may even lead to the generation of false targets. Summary of the Invention

[0004] To address the shortcomings of existing ground-based mobile measurement systems, particularly their vibration errors and inability to provide standard magnetic maps at the same measurement height on the same plane, thus failing to meet practical detection requirements, a scalar magnetic anomaly ground-based mobile measurement system and magnetic map measurement method are provided.

[0005] A magnetograph measurement method according to one aspect of an embodiment of this application includes: Place the two scalar sensors vertically at different heights; Obtain magnetic anomaly data after balancing two scalar sensors and the three-dimensional position data of the corresponding measuring points; Based on the elevation data measured by the two scalar magnetic sensors, calculate the elevation of the calculation surface extended upward from the data of the lower scalar sensor after leveling. Based on the elevation of the upward extension calculation surface, the measurement data of the lower scalar sensor is extended upward to the calculation surface to obtain the extended magnetic anomaly data; Calculate the Pearson correlation coefficient between the extended magnetic anomaly data and the anomaly data of the upper scalar magnetic sensor; Obtain a correlation threshold and determine whether the Pearson correlation coefficient between the extended magnetic anomaly data and the magnetic anomaly data of the upper scalar magnetic sensor is greater than or equal to the correlation threshold. If the Pearson correlation coefficient between the extended magnetic anomaly data and the magnetic anomaly data of the upper scalar magnetic sensor is greater than or equal to the correlation threshold, then the extended magnetic anomaly data is the measured magnetic map.

[0006] Furthermore, based on the elevation data from the two scalar magnetic sensors, the elevation of the calculation surface extending upwards from the leveled data of the lower scalar sensor is calculated, including: , This represents the total number of magnetic anomaly data. This provides the Z-axis position information of the magnetic anomaly data after leveling the scalar magnetic sensor above. The Z-axis position information for the magnetic anomaly data after leveling the scalar magnetic sensor is shown below. To calculate the surface elevation.

[0007] Further, based on the elevation of the upwardly extended calculation surface, the measurement data from the lower scalar sensor is extended upwards to the calculation surface to obtain extended magnetic anomaly data, including: The corresponding spectrum data is obtained by performing a Fourier transform on the data after leveling the scalar sensor below; Multiply the spectral data by the upward extension factor to obtain the spectral data extended upward to the computational surface; The inverse Fourier transform of the spectral data of the computational surface is performed to obtain the extended magnetic anomaly data.

[0008] Furthermore, if the Pearson correlation coefficient between the extended magnetic anomaly data and the magnetic anomaly data of the upper scalar magnetic sensor is less than the correlation threshold, the upward extension calculation needs to be performed again.

[0009] A scalar magnetic anomaly ground movement measurement system according to a second aspect of an embodiment of this application includes: a lower scalar magnetic sensor and an upper scalar magnetic sensor, an RTK antenna, an inertial measurement unit, a data acquisition and recording device, and a connecting rod; wherein... The connecting rod is vertically connected to the instrument mounting platform. An RTK antenna is installed at the top of the connecting rod. A lower scalar magnetic sensor and an upper scalar magnetic sensor are installed at different heights of the connecting rod. The inertial measurement unit is installed on the instrument mounting platform. The data acquisition and recording device simultaneously collects data from the inertial measurement unit, the RTK antenna, and the lower and upper scalar magnetic sensors.

[0010] Furthermore, it also includes a host computer, which is used to obtain the magnetic anomaly data after the two scalar sensors are leveled and the three-dimensional position data of the corresponding measuring points, and to process the data to obtain a magnetic map.

[0011] Compared with the prior art, the advantages of this application are as follows: This application uses two scalar magnetic sensors as mutual references, extends the data of one scalar magnetic sensor upward to further reduce the vibration error of the system and create a magnetograph, and verifies the validity of the magnetograph by using the data of the two scalar magnetic sensors, thereby improving the accuracy of the measurement movement. Through extension calculation, the vibration error caused by ground undulation can be effectively reduced. Attached Figure Description

[0012] Figure 1 The scalar magnetic anomaly ground movement measurement system provided in the embodiments of this application; Figure 2 A flowchart of a method for creating a magnetogram provided in an embodiment of this application; Figure 3 This is a diagram showing the measurement data after the upper sensor has been leveled, provided in an embodiment of this application. Figure 4 The measurement data diagram of the sensor after leveling is provided in the embodiment of this application; Figure 5 The measurement data after leveling the lower sensor provided in the embodiments of this application is extended upwards (magnetogram). Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0014] like Figure 1 The diagram shows a scalar magnetic anomaly ground mobile measurement system, which includes a non-magnetic vehicle frame 1, a vibration damping device 2, an instrument mounting platform 3, an inertial measurement unit 4, a lower scalar magnetic sensor 5 and an upper scalar magnetic sensor 6, an RTK antenna 7, a data acquisition and recording device 8, and a connecting rod 9.

[0015] The non-magnetic vehicle frame 1 employs a three-wheel design to enhance the system's operability and flexibility. The detachable single front wheel is used for controlling the direction of movement during manual measurement; in towed measurement, it can be detached to connect the system to the towing platform. A vibration damping device 2 provides a damping connection between the instrument mounting platform 3 and the non-magnetic vehicle frame 1. When operating in field environments, the vibration damping device 2 absorbs vibrations generated by the non-magnetic vehicle frame 1 during movement, reducing or even eliminating the vibration amplitude of the magnetic measuring instrument, thereby reducing vibration errors and improving magnetic measurement accuracy.

[0016] The inertial measurement unit 4 and the data acquisition and recording device 8 are both mounted on the instrument platform 3. The connecting rod 9 is vertically connected to the instrument platform 3. The top of the connecting rod 9 is equipped with an RTK antenna 7. The lower scalar magnetic sensor 5 and the upper scalar magnetic sensor 6 are installed at different heights of the connecting rod 9.

[0017] A spatial rectangular coordinate system is established with the direction of movement of the ground mobile measurement system as the Y-axis, the right side of the forward direction as the X-axis, and the Z-axis pointing vertically upward.

[0018] The length of the connecting rod 9 needs to be set according to the measurement accuracy and the magnetic interference intensity of the measurement area. The inertial measurement unit 4 is fixed on the instrument mounting platform 3. It measures the pitch angle, yaw angle, roll angle and three-axis acceleration information during the movement of the ground mobile measurement system, and forms a strapdown inertial navigation device with the RTK antenna 7 to provide centimeter-level position positioning accuracy for the ground mobile measurement system.

[0019] The RTK antenna 7 is positioned above the scalar sensor along the Z-axis via a connecting rod 9. The length of the connecting rod must be greater than 0.4 meters (0.56 meters in this embodiment) to reduce the intensity of magnetic interference generated at the location of the scalar magnetic sensor. The data acquisition and recording device 8 simultaneously acquires data from the inertial measurement unit 4, the RTK antenna 7, and the lower and upper scalar magnetic sensors 5 and 6.

[0020] It also includes a host computer, which is used to obtain the magnetic anomaly data after the two scalar sensors are leveled and the three-dimensional position data of the corresponding measuring points, and to process the data to obtain a magnetic map.

[0021] See Figure 2 As shown, a magnetogram measurement method is characterized by comprising: Place the two scalar sensors vertically at different heights; Obtain magnetic anomaly data after balancing two scalar sensors and the three-dimensional position data of the corresponding measuring points; Based on the elevation data measured by the two scalar magnetic sensors, calculate the elevation of the calculation surface extended upward from the data of the lower scalar sensor after leveling. Based on the elevation of the upward extension calculation surface, the measurement data of the lower scalar sensor is extended upward to the calculation surface to obtain the extended magnetic anomaly data; Calculate the Pearson correlation coefficient between the extended magnetic anomaly data and the anomaly data of the upper scalar magnetic sensor; Obtain a correlation threshold and determine whether the Pearson correlation coefficient between the extended magnetic anomaly data and the magnetic anomaly data of the upper scalar magnetic sensor is greater than or equal to the correlation threshold. If the Pearson correlation coefficient between the extended magnetic anomaly data and the magnetic anomaly data of the upper scalar magnetic sensor is greater than or equal to the correlation threshold, then the extended magnetic anomaly data is the measured magnetic map.

[0022] In actual measurement, the calibrated magnetic anomaly data of the two scalar magnetic sensors and the corresponding three-dimensional position data of the measuring points are first obtained. as well as .in, , , These are the X-axis, Y-axis, and Z-axis position information of the magnetic anomaly data after the scalar magnetic sensor above has been leveled. , , The figures below show the X, Y, and Z axis position information of the magnetic anomaly data after the scalar magnetic sensor has been leveled. This represents the magnetic anomaly data measured by the scalar magnetic sensor above. This represents the magnetic anomaly data after balancing the scalar magnetic sensors below. Due to the synchronous acquisition method, the total number of magnetic anomaly data from both scalar magnetic sensors is equal. The magnetic anomaly data after leveling the upper and lower scalar sensors are as follows: Figure 3 and Figure 4 As shown.

[0023] Based on the elevation data measured by the two scalar magnetic sensors, the elevation of the upward extension calculation surface of the data after leveling the lower scalar sensor is obtained. In one example, it is 2.14 - 1.57 = 0.57m.

[0024] Based on the elevation of the upward extension calculation surface, the measurement data of the lower scalar sensor is extended upward to the calculation surface: First, the data of the lower scalar sensor after leveling is... Perform a Fourier transform to obtain the corresponding spectrum data Then, the spectral data is multiplied by the upward extension factor to obtain the spectral data extended upward to the computational surface: Finally, for Perform inverse Fourier transform to obtain extended magnetic anomaly data. .in, For continuum magnetic anomaly data, This provides the three-dimensional location information corresponding to the continuum magnetic anomaly data. This represents the total number of data points. Extension calculations can effectively reduce vibration errors caused by ground undulations, such as... Figure 5 As shown.

[0025] Calculate the Pearson correlation coefficient between the extended magnetic anomaly data and the anomaly data of the upper scalar magnetic sensor: ; ; ; in, This represents the mean of the leveling magnetic anomaly data from the scalar magnetic sensor above. This represents the mean of the extended magnetic anomaly data.

[0026] Obtain the correlation threshold Determine the Pearson correlation coefficient between the extended magnetic anomaly data and the magnetic anomaly data from the upper variable magnetic sensor. Is it greater than or equal to the correlation threshold? .like This indicates that the upward extension of the data after leveling the scalar sensor below converges reliably and can be considered a magnetogram result. If This indicates that the relevant continuation results are unreliable and that upward continuation calculations need to be performed again until the requirements are met.

[0027] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for measuring magnetograms, characterized in that, The method includes: Place the two scalar sensors vertically at different heights; Obtain magnetic anomaly data after balancing two scalar sensors and the three-dimensional position data of the corresponding measuring points; Based on the elevation data measured by the two scalar magnetic sensors, calculate the elevation of the calculation surface extended upward from the data of the lower scalar sensor after leveling. Based on the elevation of the upward extension calculation surface, the measurement data of the lower scalar sensor is extended upward to the calculation surface to obtain the extended magnetic anomaly data; Calculate the Pearson correlation coefficient between the extended magnetic anomaly data and the anomaly data of the upper scalar magnetic sensor; Obtain a correlation threshold and determine whether the Pearson correlation coefficient between the extended magnetic anomaly data and the magnetic anomaly data of the upper scalar magnetic sensor is greater than or equal to the correlation threshold. If the Pearson correlation coefficient between the extended magnetic anomaly data and the magnetic anomaly data of the upper scalar magnetic sensor is greater than or equal to the correlation threshold, then the extended magnetic anomaly data is the measured magnetic map.

2. The magnetogram measurement method according to claim 1, characterized in that, Based on the elevation data from the two scalar magnetic sensors, the elevation of the calculation surface extending upwards from the leveled data of the lower scalar sensor is calculated as follows: , This represents the total number of magnetic anomaly data. This provides the Z-axis position information of the magnetic anomaly data after leveling the scalar magnetic sensor above. The Z-axis position information for the magnetic anomaly data after leveling the scalar magnetic sensor is shown below. To calculate the surface elevation.

3. The magnetogram measurement method according to claim 1, characterized in that, Based on the elevation of the upwardly extended calculation surface, the measurement data from the lower scalar sensor is extended upwards to the calculation surface to obtain extended magnetic anomaly data, including: The corresponding spectrum data is obtained by performing a Fourier transform on the data after leveling the scalar sensor below; Multiply the spectral data by the upward extension factor to obtain the spectral data extended upward to the computational surface; The inverse Fourier transform of the spectral data of the computational surface is performed to obtain the extended magnetic anomaly data.

4. The magnetogram measurement method according to claim 1, characterized in that, If the Pearson correlation coefficient between the extended magnetic anomaly data and the magnetic anomaly data of the upper scalar magnetic sensor is less than the correlation threshold, the upward extension calculation needs to be performed again.

5. A scalar magnetic anomaly ground movement measurement system, used to implement the magnetic map measurement method according to any one of claims 1-4, characterized in that, include: The system includes a lower scalar magnetic sensor, an upper scalar magnetic sensor, an RTK antenna, an inertial measurement unit, a data acquisition and recording device, and a connecting rod; among which, The connecting rod is vertically connected to the instrument mounting platform. An RTK antenna is installed at the top of the connecting rod. A lower scalar magnetic sensor and an upper scalar magnetic sensor are installed at different heights of the connecting rod. The inertial measurement unit is installed on the instrument mounting platform. The data acquisition and recording device simultaneously collects data from the inertial measurement unit, the RTK antenna, and the lower and upper scalar magnetic sensors.

6. The scalar magnetic anomaly ground movement measurement system according to claim 5, characterized in that, It also includes a host computer, which is used to obtain the magnetic anomaly data after the two scalar sensors are leveled and the three-dimensional position data of the corresponding measuring points, and to process the data to obtain a magnetic map.

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