A method for underwater ferromagnetic target detection based on 50Hz power grid radiation source

Abstract

The present application belongs to the interdisciplinary technical field of non-acoustic underwater detection and multi-dimensional signal processing technology, and specifically discloses a method for detecting underwater ferromagnetic targets based on a 50Hz power grid radiation source, the method comprising: acquiring a magnetic field data set above the water area where the underwater ferromagnetic target is located; performing data processing on the magnetic field data set to obtain a 50Hz frequency domain signal; extracting the phase point number characteristics of the 50Hz frequency domain signal, and based on the phase point number characteristics, determining the target area and non-target area in the water area where the underwater ferromagnetic target is located, the target area being the area where the underwater ferromagnetic target is located, and the non-target area being the area outside the target area; reconstructing a phase waveform based on the phase peaks of the target area and the non-target area in each phase time window; and determining the position of the underwater ferromagnetic target based on the reconstructed phase waveform.

Description

Technical Field

[0001] The present application belongs to the interdisciplinary technical field of non-acoustic underwater detection and multi-dimensional signal processing technology, and more specifically, relates to a method for underwater ferromagnetic target detection based on a 50Hz power grid radiation source. Background Art

[0002] The underwater environment is complex and ever-changing. The high density of water significantly restricts the propagation of acoustic and electromagnetic waves. Signals are absorbed and scattered as they propagate through water, making the detected signal extremely weak or even drowned out by background noise. In particular, the speed of acoustic waves in water is affected by temperature, salinity, and pressure, making the signal path complex and unpredictable.

[0003] In addition, the background noise in the underwater environment comes from a wide range of sources, including the activities of marine life, the noise of ships, the natural noise of the ocean itself, etc. These noises will interfere with the detection signal and increase the difficulty of signal processing. The complexity of underwater terrain, such as seabed mountains, canyons and sediments, will also affect signal propagation, making detection more difficult. To overcome these challenges, traditional underwater detection methods such as improving sonar systems, developing new underwater sensors, and applying advanced signal processing algorithms are used to improve the accuracy and efficiency of underwater detection. However, traditional underwater detection methods often face problems such as low signal-to-noise ratio, poor resolution, and limited detection distance. The detection effect of underwater ferromagnetic targets is poor, and the reliability and accuracy are low. Summary of the Invention

[0004] In response to the defects of the existing technology, the purpose of this application is to provide a method for detecting underwater ferromagnetic targets based on a 50Hz power grid radiation source, aiming to solve the defects of the existing underwater detection means in the field, such as poor detection effect of underwater ferromagnetic targets, low reliability and accuracy due to problems such as low signal-to-noise ratio, poor resolution and limited detection distance.

[0005] To achieve the above objectives, in a first aspect, the present application provides a method for detecting underwater ferromagnetic targets based on a 50Hz power grid radiation source, comprising:

[0006] Obtain a magnetic field dataset above the waters where underwater ferromagnetic targets are located;

[0007] Processing the magnetic field data set to obtain a 50 Hz frequency domain signal;

[0008] Extracting a phase point number feature of the 50 Hz frequency domain signal, and determining a target area and a non-target area in the water area where the underwater ferromagnetic target is located based on the phase point number feature, wherein the target area is the area where the underwater ferromagnetic target is located, and the non-target area is the area outside the target area;

[0009] Reconstructing the phase waveform based on the phase peaks of the target area and the non-target area in each phase time window;

[0010] The position of the underwater ferromagnetic target is determined based on the reconstructed phase waveform.

[0011] This application separates the signals by performing phase angle decomposition of the 50Hz power frequency domain signal of the magnetic field in the water area of ​​the underwater ferromagnetic target, thereby accurately evaluating the strength and characteristics of each signal, and then reconstructing the phase waveform based on the phase peak to determine the position of the underwater ferromagnetic target. This not only helps to improve the accuracy of signal processing, but also can better understand and utilize signal information in complex environments, effectively reduce interference between signals, and improve the reliability and accuracy of underwater ferromagnetic target detection.

[0012] According to the underwater ferromagnetic target detection method based on a 50 Hz power grid radiation source provided by the present invention, the data processing of the magnetic field data set to obtain a 50 Hz frequency domain signal includes:

[0013] Performing Fourier transform on the magnetic field data set to obtain a frequency domain signal;

[0014] A 50 Hz frequency domain signal is extracted from the frequency domain signal.

[0015] This application performs Fourier transform on the acquired magnetic field time series data to convert it into a frequency domain signal, thereby extracting the frequency domain signal of the industrial frequency 50Hz, preparing for the subsequent extraction of phase point number features.

[0016] According to the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source provided by the present invention, the target area and non-target area in the water area where the underwater ferromagnetic target is located are determined based on the phase point number feature, including:

[0017] The area with the corresponding phase peak relationship in the phase point number feature is determined as the non-target area, and the area without the corresponding phase peak relationship in the phase point number feature is determined as the target area.

[0018] Since the phase changes of industrial frequency electromagnetic waves are different in areas far away from the target area and those close to the target area, this application determines the area with corresponding phase peak relationship in the phase point number characteristics as a non-target area, and determines the area without corresponding phase peak relationship in the phase point number characteristics as a target area, thereby improving the accuracy of target area determination.

[0019] According to the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source provided by the present invention, the phase waveform is reconstructed based on the phase peaks of the target area and the non-target area in each phase time window, including:

[0020] Comparing the phase peaks of the target area and the non-target area in each phase time window, and performing phase superposition on the phases with a changed number of phase points;

[0021] The phase waveform is reconstructed based on the superimposed phase.

[0022] According to the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source provided by the present invention, the phase waveform reconstructed based on the superimposed phase includes:

[0023] Based on the superimposed phase, the time corresponding to the phase with the changed number of phase points is obtained;

[0024] Based on the corresponding time, extracting the amplitude at the corresponding time;

[0025] The phase waveform is reconstructed based on the phase with a changing number of phase points and the amplitude at the corresponding time.

[0026] According to the underwater ferromagnetic target detection method based on a 50 Hz power grid radiation source provided by the present invention, determining the position of the underwater ferromagnetic target based on the reconstructed phase waveform includes:

[0027] Count all the reconstructed phase waveforms obtained, and count the windows with the highest waveform peak change;

[0028] Take out all overlapping windows and record the location and time of their occurrence;

[0029] Performing target matching on the overlapping window portions to obtain a matching window overlap ratio;

[0030] If the matching window overlap rate is greater than a preset threshold, the position and time of the window overlap portion are determined as the position of the underwater ferromagnetic target.

[0031] In a second aspect, the present application provides an underwater ferromagnetic target detection device based on a 50Hz power grid radiation source, comprising:

[0032] An acquisition module is used to obtain a magnetic field dataset above the waters where the underwater ferromagnetic target is located;

[0033] a processing module, configured to process the magnetic field data set to obtain a 50 Hz frequency domain signal;

[0034] A first determination module is configured to extract a phase point number feature of the 50 Hz frequency domain signal, and determine a target area and a non-target area in the water area where the underwater ferromagnetic target is located based on the phase point number feature, wherein the target area is the area where the underwater ferromagnetic target is located, and the non-target area is the area outside the target area;

[0035] A reconstruction module, for reconstructing a phase waveform based on the phase peaks of the target area and the non-target area in each phase time window;

[0036] The second determination module is used to determine the position of the underwater ferromagnetic target based on the reconstructed phase waveform.

[0037] In a third aspect, the present application provides an electronic device comprising: at least one memory for storing programs; and at least one processor for executing the programs stored in the memory. When the programs stored in the memory are executed, the processor is used to execute the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source described in the first aspect or any possible implementation of the first aspect.

[0038] In a fourth aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source described in the first aspect or any possible implementation of the first aspect.

[0039] In a fifth aspect, the present application provides a computer program product, which, when running on a processor, enables the processor to execute the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source described in the first aspect or any possible implementation of the first aspect.

[0040] It can be understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0041] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies:

[0042] By performing phase angle decomposition of the 50Hz frequency domain signal of the magnetic field in the water area of ​​the underwater ferromagnetic target, these signals are separated to accurately evaluate the strength and characteristics of each signal. Then, based on the phase peak, the phase waveform is reconstructed to determine the position of the underwater ferromagnetic target. This not only helps to improve the accuracy of signal processing, but also better understand and utilize signal information in complex environments, effectively reduce interference between signals, and improve the reliability and accuracy of underwater ferromagnetic target detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 1 is a flow chart of a method for detecting underwater ferromagnetic targets based on a 50Hz power grid radiation source provided in an embodiment of the present application;

[0045] Figure 2 This is a schematic diagram of the phase superposition process provided in an embodiment of the present application;

[0046] Figure 3 This is a schematic diagram of the waveform reconstruction process provided by an embodiment of the present application;

[0047] Figure 4 This is one of the schematic diagrams of the relationship between the starting position of longitude and latitude of the test provided in the embodiment of the present application;

[0048] Figure 5 This is one of the schematic diagrams of the relationship between the test latitude and longitude termination positions provided in the embodiments of the present application;

[0049] Figure 6 This is one of the schematic diagrams of the distance relationship between the drone and the underwater ferromagnetic target at each moment provided in the embodiment of the present application;

[0050] Figure 7 This is one of the target area phase peak relationship diagrams provided in the embodiments of the present application;

[0051] Figure 8 This is one of the non-target area phase peak relationship diagrams provided in the embodiments of the present application;

[0052] Figure 9 This is one of the schematic diagrams of the X-axis matching results provided in the embodiment of the present application;

[0053] Figure 10 This is one of the Y-axis matching result diagrams provided in the embodiments of the present application;

[0054] Figure 11 This is one of the Z-axis matching result diagrams provided in the embodiments of the present application;

[0055] Figure 12 This is one of the X-axis automatic matching positioning signal diagrams provided in the embodiment of the present application;

[0056] Figure 13 This is one of the Y-axis automatic matching positioning signal diagrams provided in the embodiment of the present application;

[0057] Figure 14 This is one of the Z-axis automatic matching positioning signal diagrams provided in the embodiment of the present application;

[0058] Figure 15 This is the second schematic diagram of the relationship between the starting position of longitude and latitude of the test provided in the embodiment of the present application;

[0059] Figure 16 This is the second schematic diagram of the relationship between the test latitude and longitude termination positions provided in the embodiment of this application.

[0060] Figure 17 This is the second schematic diagram of the distance relationship between the drone and the underwater ferromagnetic target at each moment provided by the embodiment of the present application;

[0061] Figure 18 This is the second target area phase peak relationship diagram provided in the embodiment of the present application;

[0062] Figure 19 This is the second schematic diagram of the relationship between the phase peak values ​​of the non-target area provided in the embodiment of the present application;

[0063] Figure 20 This is the second schematic diagram of the X-axis matching result provided in the embodiment of the present application;

[0064] Figure 21 This is the second schematic diagram of the Y-axis matching result provided in the embodiment of the present application;

[0065] Figure 22 This is the second schematic diagram of the Z-axis matching result provided in the embodiment of the present application;

[0066] Figure 23 This is the second X-axis automatic matching positioning signal diagram provided in the embodiment of the present application;

[0067] Figure 24 This is the second Y-axis automatic matching positioning signal diagram provided in the embodiment of the present application;

[0068] Figure 25 This is the second Z-axis automatic matching positioning signal diagram provided in an embodiment of the present application;

[0069] Figure 26 This is a schematic structural diagram of an underwater ferromagnetic target detection device based on a 50Hz power grid radiation source provided in an embodiment of the present application;

[0070] Figure 27 It is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0072] The term "and / or" as used herein describes an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. The symbol " / " as used herein indicates that the related objects are in an "or" relationship, for example, A / B means either A or B.

[0073] The terms "first" and "second" in this specification and claims are used to distinguish different objects rather than to describe a specific order of objects. For example, "first response message" and "second response message" are used to distinguish different response messages rather than to describe a specific order of response messages.

[0074] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0075] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more, for example, multiple processing units means two or more processing units, etc.; multiple elements means two or more elements, etc.

[0076] First, let's introduce the following:

[0077] It's generally believed that the signals from underwater targets are weak, posing numerous challenges for underwater detection. However, experimental results show that the signals emitted by power grids are actually quite strong. This discovery overturns the commonly held belief about power grid signal strength. Specifically, as the power-frequency electromagnetic waves emitted by power grids in various countries propagate through the Earth's surface, their phase shifts due to differences in geological structure, propagation distance, and the geographic location of power grids. When these waves with different phases meet in space, they can interfere and cancel each other out. This mutual interference and cancellation is what causes the apparent weak signal strength we measure.

[0078] This phenomenon demonstrates a significant discrepancy between the actual strength of power grid signals and the signal strength measured on the surface. When multiple signals from different directions reach the same location, they can cancel each other out, causing the overall signal to appear weaker. However, if these signals are separated, each individual signal is actually not weaker. For example, a signal with a strength of -100 times greater plus a signal with a strength of 99 times greater results in a signal strength of -1. While the overall signal strength may appear to be weaker, the individual signals remain strong.

[0079] Next, combine Figure 1-Figure 25 The underwater ferromagnetic target detection method based on a 50Hz power grid radiation source provided in an embodiment of the present application is introduced.

[0080] Figure 1 FIG. 1 is a flow chart of an underwater ferromagnetic target detection method based on a 50Hz power grid radiation source provided in an embodiment of the present application. Figure 1 As shown, the method includes the following steps:

[0081] Step 100, obtaining a magnetic field dataset above the water area where the underwater ferromagnetic target is located;

[0082] Optionally, the present application does not limit the method for obtaining the magnetic field data set, and the data can be obtained by using a drone carrying a magnetic field data collection device, etc.

[0083] Step 110, processing the magnetic field data set to obtain a 50 Hz frequency domain signal;

[0084] After obtaining the raw data of the underwater ferromagnetic target passing through the magnetic detector, the raw data is the raw data of the aliasing of various frequencies, so it can be processed to obtain the frequency domain signal of the power frequency of 50 Hz.

[0085] Step 120, extracting the phase point number feature of the 50 Hz frequency domain signal, and determining the target area and non-target area in the water area where the underwater ferromagnetic target is located based on the phase point number feature, where the target area is the area where the underwater ferromagnetic target is located, and the non-target area is the area outside the target area;

[0086] Optionally, the phase point number feature may be a change in the number of phase points of a 50 Hz frequency domain signal in each time window.

[0087] After extracting the phase point number features, the target area and non-target area, as well as their corresponding phases and phase number windows can be determined.

[0088] Step 130 , reconstructing a phase waveform based on the phase peaks of the target area and the non-target area in each phase time window;

[0089] Step 140: Determine the position of the underwater ferromagnetic target based on the reconstructed phase waveform.

[0090] The underwater ferromagnetic target detection method based on a 50Hz power grid radiation source provided by the present invention performs phase angle decomposition of the 50Hz power frequency domain signal of the magnetic field in the water area of ​​the underwater ferromagnetic target, separates these signals, and accurately evaluates the strength and characteristics of each signal. Then, based on the phase peak, the phase waveform is reconstructed to determine the position of the underwater ferromagnetic target. This not only helps to improve the accuracy of signal processing, but also can better understand and utilize signal information in complex environments, effectively reduce interference between signals, and improve the reliability and accuracy of underwater ferromagnetic target detection.

[0091] In some embodiments, step 110 specifically includes:

[0092] Step 1101, performing Fourier transform on the magnetic field data set to obtain a frequency domain signal;

[0093] Step 1102: extract the 50 Hz frequency domain signal from the frequency domain signal.

[0094] Specifically, the magnetic field data set d[n] is subjected to FFT transformation to obtain the frequency domain signal D[k], as shown in the following formula:

[0095]

[0096] Among them, d[n] is the original function, which is the time domain signal of the original magnetic field data set; and the transformed frequency domain signal D[k] is called the image function of Fourier transform. The original function and the image function constitute a Fourier transform pair.

[0097] In some embodiments, step 120 specifically includes:

[0098] In step 1202, the region with a corresponding phase peak relationship in the phase point number feature is determined as a non-target region, and the region without a corresponding phase peak relationship in the phase point number feature is determined as a target region.

[0099] In the phase, a peak represents a major emission source, and the emission source will enhance these peaks. When there is an emission source nearby, these peak characteristics will be enhanced. Therefore, this application determines the target area by whether there is a corresponding phase peak relationship in the phase point number characteristics.

[0100] Specifically, the area with a corresponding phase peak relationship in the phase point number feature is determined as a non-target area, and the area without a corresponding phase peak relationship in the phase point number feature is determined as a target area.

[0101] In some embodiments, step 130 specifically includes:

[0102] Step 1301 , comparing the phase peaks of the target area and the non-target area in each phase time window, and performing phase superposition on the phases with a changed number of phase points;

[0103] Step 1302: reconstruct the phase waveform based on the superimposed phase.

[0104] Figure 2 This is a schematic diagram of the phase superposition process provided in the embodiment of the present application. Figure 2 As shown in the figure, for the obtained phase point information of the target area and non-target area windows, the phase point trough corresponding to each pair of phase point peaks is compared, the phase with no change in point count is eliminated, and the phase with changed point count is phase superimposed. The phase change θ of 50Hz is counted separately. i Number.

[0105] In some embodiments, step 1302 specifically includes:

[0106] Step 13021: Based on the superimposed phase, obtain the time corresponding to the phase where the number of phase points changes;

[0107] Step 13022: extracting the amplitude at the corresponding time based on the corresponding time;

[0108] Step 13023, reconstructing the phase waveform based on the phase with the changed number of phase points and the amplitude at the corresponding time.

[0109] Figure 3 This is a schematic diagram of the waveform reconstruction process provided by the embodiment of the present application. Figure 3 As shown, first, the superimposed phase is returned to the original phase spectrum to find the time corresponding to the changed phase. Then, specifically, the original data is returned through time to extract the amplitude at the corresponding time, and finally the waveform is reconstructed through Acos.

[0110] Specifically, the Acos waveform reconstruction formula is: the initial phase of the reflected wave = the initial phase of the origin vibration. Phase delay = path delay + half-wave loss. The incident wave function is expressed in the general form y = Acos [wt - kx + phi]. If the reflection end is fixed, the reflected wave has half-wave loss, expressed as y' = Acos [wt + kx + phi + Pi]. If the reflection end is free, the reflected wave has no half-wave loss, expressed as y' = Acos [wt + kx + phi], where A is the amplitude at the corresponding time, t is the corresponding time, w is the angular frequency, k is the wave number, phi is the initial phase, and Pi is radians.

[0111] The wave function is a probability wave, and the square of its modulus represents the probability density of the particle appearing at that location. Since it is a probability wave, it naturally has normalization, that is, it is integrated over the entire space.

[0112] However, in most cases, the wave function obtained by the Schrödinger equation is not normalized. It needs to be multiplied by a coefficient N in front, that is, it needs to be brought into the normalization condition and solved for N. Only then is the normalized wave function obtained, where N is not unique.

[0113] In some embodiments, step 140 specifically includes:

[0114] Step 1401: Count all the reconstructed phase waveforms obtained, and count the windows with the highest waveform peak change;

[0115] Step 1402: remove all overlapping windows and record their locations and times.

[0116] Step 1403: performing target matching on the overlapping window portions to obtain a matching window overlap ratio;

[0117] Specifically, the matching window overlap rate is obtained, that is, the phase peaks of the selected target area and non-target area are compared. At the same frequency, the X, Y, and Z axis reconstructed waveform data are used for target matching and voting, that is, the window with the maximum waveform fluctuation is matched with the window determined under the longitude and latitude. Through the automatic matching mechanism, the position area of ​​the underwater ferromagnetic target can be located.

[0118] Step 1404: If the matching window overlap ratio is greater than a preset threshold, the position and time of the window overlap portion are determined as the position of the underwater ferromagnetic target.

[0119] Optionally, the preset threshold can be flexibly set according to demand or actual conditions. In one embodiment of the present application, it is set to 40%.

[0120] In one embodiment of the present application, the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source of the present application was verified by using a drone to detect underwater ferromagnetic targets in the Zhanghe Reservoir. The underwater ferromagnetic target detected weighed 10 tons, was made of Q235 steel, had a steel wall thickness of 1 cm, was about 8 meters long, and had a diameter of about 1 meter. The steps were as follows:

[0121] 1. Hovering test

[0122] The test conditions are that the UUV theoretically flies at a height of 70m, the UUV is hovering, the UUV is navigating underwater with a ferromagnetic target, the theoretical navigation depth is 10m, and the navigation speed is 13 knots.

[0123] Figure 4 This is one of the schematic diagrams of the relationship between the starting longitude and latitude of the test provided in the embodiment of the present application. The relationship between the starting longitude and latitude of the drone and the underwater ferromagnetic target is as follows: Figure 4 shown.

[0124] Figure 5This is one of the schematic diagrams of the relationship between the test longitude and latitude termination positions provided in the embodiment of the present application. The relationship between the longitude and latitude termination positions of the drone and the underwater ferromagnetic target is as follows: Figure 5 shown.

[0125] The red dots in the figure represent the test start positions of the drone and the underwater ferromagnetic target at the same time, corresponding to Beijing time. The underwater ferromagnetic target's translational motion period starts at 140 seconds and ends at 400 seconds.

[0126] Figure 6 This is one of the schematic diagrams of the distance relationship between the drone and the underwater ferromagnetic target at each moment provided by the embodiment of the present application. The distance relationship between the drone and the underwater ferromagnetic target at each moment is as follows: Figure 6 As shown in the red box, the time relationship between the UAV and the underwater ferromagnetic target during the test period.

[0127] Figure 7 This is one of the target area phase peak relationship diagrams provided in the embodiment of the present application, such as Figure 7 As shown, based on the relationship between the test latitude and longitude and distance, with a 20s window, the 50Hz target area is 300s-320s.

[0128] Figure 8 This is one of the non-target area phase peak relationship diagrams provided in the embodiment of the present application, such as Figure 8 As shown, based on the relationship between the test latitude and longitude and distance, with a 20s window, the 50Hz non-target area is 80s-100s.

[0129] A 50Hz emission source will enhance these peaks. Based on the UAV flight test, the phase number characteristics of the non-target area of ​​the 50Hz industrial frequency electromagnetic wave extracted show that 20 peaks and valleys can be selected. At the same time, the phase of the target area at the corresponding time is selected, and the phase with changes is compared as the part of the phase change in the target area.

[0130] The phase peaks of the selected target and non-target areas are compared. At the same frequency, the X, Y, and Z axes reconstruct waveform data for target matching and voting. This involves matching the window with the maximum waveform fluctuation with the window determined by the longitude and latitude. Through this automatic matching mechanism, the location of the underwater ferromagnetic target can be located.

[0131] Figure 9 This is one of the X-axis matching result diagrams provided in the embodiment of the present application. Figure 9 As shown in the figure, the green box is the final overlapping result, and the red dotted box is the matching result. The window is reduced from the original 30s to 7s, which further improves the positioning accuracy.

[0132] Figure 10 This is one of the Y-axis matching result diagrams provided in the embodiment of the present application. Figure 10As shown in the figure, the red dotted box is the matching result. The original 30s window is reduced to a 3s window, and the positioning accuracy is further improved. However, due to the system error, it deviates from the target window and has a certain degree of advance.

[0133] Figure 11 This is one of the Z-axis matching result diagrams provided in the embodiment of the present application. Figure 11 As shown in the figure, the red dotted box is the matching result. The original 30s window is reduced to 1s window, and the positioning accuracy is further improved.

[0134] Figure 12 This is one of the X-axis automatic matching positioning signal diagrams provided in the embodiment of the present application. Figure 13 This is one of the Y-axis automatic matching positioning signal diagrams provided in the embodiment of the present application. Figure 14 This is one of the Z-axis automatic matching positioning signal diagrams provided in the embodiment of the present application. The test data of the 50Hz X-axis, Y-axis and Z-axis phase angle automatic matching are as follows: Figure 12-14 shown.

[0135] The results show that the automatic matching of reconstructed waveforms at different phase angles, voting for different HZ numbers and different X, Y, and Z axes, and a detection rate exceeding 40% indicates that the target has been detected, preliminarily verifying the feasibility of this algorithm.

[0136] 2. Scanning test

[0137] Test conditions: The UUV theoretical flight altitude is 25m, the UUV is hovering, the UUV is sailing underwater with an underwater ferromagnetic target, the theoretical sailing depth is 10m, and the sailing speed is 13 knots.

[0138] Figure 15 This is the second schematic diagram of the relationship between the starting longitude and latitude of the test provided in the embodiment of the present application. The relationship between the starting longitude and latitude of the drone and the underwater ferromagnetic target is as follows: Figure 15 shown.

[0139] Figure 16 This is the second schematic diagram of the relationship between the test longitude and latitude termination positions provided in the embodiment of the present application. The relationship between the longitude and latitude termination positions of the drone and the underwater ferromagnetic target is as follows: Figure 16 shown.

[0140] The red dot in the figure represents the starting position of the UAV and the underwater ferromagnetic target at the same time, corresponding to Beijing time. The underwater ferromagnetic target's underwater navigation translation time period starts at 60 seconds and ends at 120 seconds.

[0141] Figure 17 This is a second schematic diagram of the distance relationship between the drone and the underwater ferromagnetic target at each moment provided by the embodiment of the present application. The distance relationship between the drone and the underwater ferromagnetic target at each moment is as follows: Figure 17As shown in the red box, the time relationship between the UAV and the underwater ferromagnetic target during the test period.

[0142] Figure 18 This is the second target area phase peak relationship diagram provided in the embodiment of the present application. Figure 18 As shown, based on the relationship between the test latitude and longitude and distance, with a 20s window, the 50Hz target area is 90s-100s.

[0143] Figure 19 This is the second schematic diagram of the non-target area phase peak relationship provided in the embodiment of the present application, such as Figure 19 As shown, based on the relationship between the test latitude and longitude and distance, with a 20s window, the 50Hz non-target area is 20s-40s.

[0144] A 50Hz emission source will enhance these peaks. Based on the UAV flight test, the phase number characteristics of the non-target area of ​​the 50Hz industrial frequency electromagnetic wave extracted show that 20 peaks and valleys can be selected. At the same time, the phase of the target area at the corresponding time is selected, and the phase with changes is compared as the part of the phase change in the target area.

[0145] The phase peaks of the selected target and non-target areas are compared. At the same frequency, the X, Y, and Z axes reconstruct waveform data for target matching and voting. This involves matching the window with the maximum waveform fluctuation with the window determined by the longitude and latitude. Through this automatic matching mechanism, the location of the underwater ferromagnetic target can be located.

[0146] Figure 20 This is the second schematic diagram of the X-axis matching result provided in the embodiment of the present application. Figure 20 As shown, the green box is the final overlapping result, and the red dotted box is the matching result. The positioning accuracy is further improved by reducing the original 30s window to a 3s window. In the flight scanning test, the UAV and the underwater ferromagnetic target are moving towards each other, so the positioning window has an advanced feature.

[0147] Figure 21 This is the second schematic diagram of the Y-axis matching result provided in the embodiment of the present application. Figure 21 As shown in the figure, the red dotted box is the matching result. The original 30s window is reduced to 1s window, and the positioning accuracy is further improved. Due to the system error, it deviates from the target window and has a certain degree of advance.

[0148] Figure 22 This is the second schematic diagram of the Z-axis matching result provided in the embodiment of the present application. Figure 22 As shown in the figure, the red dotted box is the matching result. The window is reduced from the original 30s to 5s, and the positioning accuracy is further improved.

[0149] Figure 23This is the second X-axis automatic matching positioning signal diagram provided in the embodiment of the present application. Figure 24 This is the second Y-axis automatic matching positioning signal diagram provided in the embodiment of the present application. Figure 25 This is the second Z-axis automatic matching positioning signal diagram provided by the embodiment of the present application. The test data of the 50Hz X-axis, Y-axis and Z-axis phase angle automatic matching are as follows: Figure 23-25 shown.

[0150] In one embodiment of the present application, based on the Zhanghe Reservoir experiment, the phase vector relationship in the 50Hz family of original signals was obtained, and a global 50Hz power grid model was established. It was found that at different times, the number of phases of the 50Hz family (three-axis X, Y, and Z) signals had a clear relationship. The original signals of the three axes are composed of signals with different initial phases, and the formula is as follows:

[0151]

[0152] in:

[0153] m x : Amplitude of the x-axis signal, m y : Amplitude of the y-axis signal, m z : The amplitude of the z-axis signal, cos x (ωt+θ i ): x-axis signal waveform, cos y (ωt+θ i ): y-axis signal waveform, cos z (ωt+θ i ): z-axis signal waveform; θ i : The number of different initial phases decomposed from the phase relationship.

[0154] The following combination Figure 26 The underwater ferromagnetic target detection device based on a 50Hz power grid radiation source provided by the present invention is described. The underwater ferromagnetic target detection device based on a 50Hz power grid radiation source described below and the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source described above can be referenced to each other.

[0155] Figure 26 : is a structural diagram of an underwater ferromagnetic target detection device based on a 50Hz power grid radiation source provided in an embodiment of the present application, such as Figure 26 As shown, the apparatus includes an acquisition module 2610, a processing module 2620, a first determination module 2630, a reconstruction module 2640, and a second determination module 2650, wherein:

[0156] An acquisition module 2610 is used to acquire a magnetic field dataset above the water area where the underwater ferromagnetic target is located;

[0157] The processing module 2620 is used to process the magnetic field data set to obtain a 50 Hz frequency domain signal;

[0158] A first determination module 2630 is configured to extract a phase point number feature of the 50 Hz frequency domain signal and determine a target area and a non-target area in the water area where the underwater ferromagnetic target is located based on the phase point number feature, where the target area is the area where the underwater ferromagnetic target is located, and the non-target area is the area outside the target area.

[0159] A reconstruction module 2640 is configured to reconstruct a phase waveform based on the phase peaks of the target region and the non-target region in each phase time window;

[0160] The second determination module 2650 is configured to determine the position of the underwater ferromagnetic target based on the reconstructed phase waveform.

[0161] It should be understood that the above-mentioned device is used to execute the method in the above-mentioned embodiment. The implementation principle and technical effect of the corresponding program module in the device are similar to those described in the above-mentioned method. The working process of the device can refer to the corresponding process in the above-mentioned method and will not be repeated here.

[0162] Based on the method in the above embodiment, Figure 27 An example of a physical structure diagram of an electronic device is shown below. Figure 27 As shown, an embodiment of the present application provides an electronic device, which may include: a processor (processor) 2710, a communication interface (CommunicationsInterface) 2720, a memory (memory) 2730 and a communication bus 2740, wherein the processor 2710, the communication interface 2720, and the memory 2730 communicate with each other through the communication bus 2740. The processor 2710 can call the logic instructions in the memory 2730 to execute the underwater ferromagnetic target detection method based on the 50Hz power grid radiation source in the above embodiment.

[0163] In addition, the logic instructions in the above-mentioned memory 2730 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source described in each embodiment of the present application.

[0164] Based on the method in the above embodiment, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source in the above embodiment.

[0165] Based on the method in the above embodiment, an embodiment of the present application provides a computer program product. When the computer program product runs on a processor, the processor executes the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source in the above embodiment.

[0166] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0167] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC.

[0168] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted via the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state drive (SSD)).

[0169] It will be understood that the various numerical numbers involved in the embodiments of the present application are merely distinctions for the convenience of description and are not intended to limit the scope of the embodiments of the present application.

[0170] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for detecting underwater ferromagnetic targets based on a 50Hz power grid radiation source, characterized in that: include: Obtain a magnetic field dataset above the waters where underwater ferromagnetic targets are located; Processing the magnetic field data set to obtain a 50 Hz frequency domain signal; Extracting a phase point number feature of the 50 Hz frequency domain signal, and determining a target area and a non-target area in the water area where the underwater ferromagnetic target is located based on the phase point number feature, wherein the target area is the area where the underwater ferromagnetic target is located, and the non-target area is the area outside the target area; Reconstructing the phase waveform based on the phase peaks of the target area and the non-target area in each phase time window; The position of the underwater ferromagnetic target is determined based on the reconstructed phase waveform.

2. The underwater ferromagnetic target detection method based on a 50Hz power grid radiation source according to claim 1 is characterized in that: The processing of the magnetic field data set to obtain a 50 Hz frequency domain signal includes: Performing Fourier transform on the magnetic field data set to obtain a frequency domain signal; A 50 Hz frequency domain signal is extracted from the frequency domain signal.

3. The underwater ferromagnetic target detection method based on a 50Hz power grid radiation source according to claim 1 is characterized in that: The determining, based on the phase point number feature, the target area and the non-target area in the water area where the underwater ferromagnetic target is located, includes: The area with the corresponding phase peak relationship in the phase point number feature is determined as the non-target area, and the area without the corresponding phase peak relationship in the phase point number feature is determined as the target area.

4. The underwater ferromagnetic target detection method based on a 50Hz power grid radiation source according to claim 1, characterized in that: The reconstructing the phase waveform based on the phase peaks of the target area and the non-target area in each phase time window includes: Comparing the phase peaks of the target area and the non-target area in each phase time window, and performing phase superposition on the phases with a changed number of phase points; The phase waveform is reconstructed based on the superimposed phase.

5. The underwater ferromagnetic target detection method based on a 50Hz power grid radiation source according to claim 4 is characterized in that: The phase waveform reconstructed based on the superimposed phase includes: Based on the superimposed phase, the time corresponding to the phase with the changed number of phase points is obtained; Based on the corresponding time, extracting the amplitude at the corresponding time; The phase waveform is reconstructed based on the phase with a changing number of phase points and the amplitude at the corresponding time.

6. The underwater ferromagnetic target detection method based on a 50Hz power grid radiation source according to claim 1, characterized in that: The determining the position of the underwater ferromagnetic target based on the reconstructed phase waveform includes: Count all the reconstructed phase waveforms obtained, and count the windows with the highest waveform peak change; Take out all overlapping windows and record the location and time of their occurrence; Performing target matching on the overlapping window portions to obtain a matching window overlap ratio; If the matching window overlap rate is greater than a preset threshold, the position and time of the window overlap portion are determined as the position of the underwater ferromagnetic target.

7. An underwater ferromagnetic target detection device based on a 50Hz power grid radiation source, characterized in that: include: An acquisition module is used to obtain a magnetic field dataset above the waters where the underwater ferromagnetic target is located; a processing module, configured to process the magnetic field data set to obtain a 50 Hz frequency domain signal; A first determination module is configured to extract a phase point number feature of the 50 Hz frequency domain signal, and determine a target area and a non-target area in the water area where the underwater ferromagnetic target is located based on the phase point number feature, wherein the target area is the area where the underwater ferromagnetic target is located, and the non-target area is the area outside the target area; A reconstruction module, for reconstructing a phase waveform based on the phase peaks of the target area and the non-target area in each phase time window; The second determination module is used to determine the position of the underwater ferromagnetic target based on the reconstructed phase waveform.

8. An electronic device, characterized in that: include: at least one memory for storing a computer program; At least one processor is used to execute the program stored in the memory. When the program stored in the memory is executed, the processor is used to execute the underwater ferromagnetic target detection method based on a 50Hz power grid radiation source as described in any one of claims 1-6.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program runs on a processor, the processor is enabled to execute the underwater ferromagnetic target detection method based on a 50 Hz power grid radiation source as described in any one of claims 1 to 6.

10. A computer program product, characterized in that When the computer program product runs on a processor, the processor is enabled to execute the underwater ferromagnetic target detection method based on a 50 Hz power grid radiation source as described in any one of claims 1 to 6.

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