Method and system for detecting submarine underground cable through Rydberg electric field meter electromagnetic induction method

Abstract

The invention relates to the technical field of electromagnetic detection, in particular to a method and a system for detecting a submarine underground cable by an electromagnetic induction method of a Rydberg electric field meter. In the invention, direct measurement of a radio frequency electric field is introduced into a detection process, high-sensitivity sensing is carried out on a weak electric field by utilizing atomic energy level displacement, and the weak electric field is converted into an optical signal to be transmitted and demodulated, so that the problems of serious signal attenuation and noise interference of traditional electromagnetic induction equipment under deep water or complex geological conditions are effectively solved; a submarine cable which is buried deeper or has a weaker current signal can be detected, meanwhile, electric field response data containing multi-dimensional physical characteristics are constructed through electric field response amplitude and phase information obtained through pilot frequency demodulation in combination with spatial position information, a single criterion mode that positioning is carried out only by depending on a signal intensity peak value is changed, and the positioning accuracy is improved. By importing the multi-dimensional data into a neural network model for electric field image reconstruction, finer spatial distribution of the electric field around the cable can be restored.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic detection technology, and in particular to a method and system for detecting submarine underground cables using the electromagnetic induction method with a Rydberg electric field meter. Background Technology

[0002] The field of electromagnetic detection technology refers to related technologies that utilize the generation, propagation, and response characteristics of electromagnetic fields to detect underground or underwater targets, including identifying the distribution of underground structures and the presence of metals or dielectric bodies through the interaction of electric and magnetic fields.

[0003] Among them, the method of detecting submarine underground cables refers to obtaining the electric or magnetic field signals generated by the cable in the seawater environment by means of electromagnetic induction to determine its location. Common methods include detecting the magnetic field distribution formed by the transmission current through coil induction and capturing the electric field signal formed by the cable current in the seawater by electrode measurement.

[0004] Existing technologies mainly rely on coil induction to measure magnetic fields or electrode measurement to capture potential differences. In coil induction, the sensor is highly susceptible to interference from other electromagnetic sources in the environment. When the target cable is buried deep or has a thick external shielding layer, the magnetic field signal it generates is very weak by the time it reaches the seabed surface and is often drowned out by environmental background noise, making it impossible for the detector to identify effectively. In electrode measurement, electrochemical noise is generated at the contact surface between the electrode and the seawater, and the conductivity of the seawater is locally uneven due to changes in temperature and salinity. These factors all introduce measurement errors, making the measurement results of the electric field signal unstable. In addition, both methods usually rely on finding the maximum signal strength to determine the cable position. When there are multiple parallel cables or other metal conductors nearby causing electromagnetic field distortion, the position of the signal peak may deviate from directly above the cable. Positioning based solely on the field strength amplitude will result in positioning errors or even incorrect judgments. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and proposes a method and system for detecting submarine underground cables using the electromagnetic induction method of the Rydberg electric field meter.

[0006] To achieve the above objectives, the present invention employs the following technical solution: a method for detecting submarine underground cables using the electromagnetic induction method with a Rydberg electric field meter, comprising the following steps: S1: By applying an alternating electrical signal to the target pipeline through the transmitter, electromagnetic radiation signals are generated in the underground metal pipeline on the seabed. The amplitude of the radiated electromagnetic field signal is matched with the frequency of the corresponding applied excitation signal to construct a target excitation parameter set. S2: The target excitation parameter set is used to excite the induced current in the seabed subsurface target detection area, and the changes in atomic energy levels caused by the alternating electric field are measured to form a transmission electrical signal sequence; S3: Use the optical excitation signal group to irradiate the alkali metal vapor pool in the underwater probe to excite the Rydberg state atoms to sense the energy level shift caused by the radio frequency electric field and output the perturbation phase data set. S4: Perform frequency conversion and demodulation processing on the transmitted electrical signal sequence and the disturbance phase dataset, and bind the three-dimensional spatial position of the underwater probe after frequency conversion and demodulation processing with the transmission parameters to form an electric field response spatial data table. S5: Based on the three-dimensional spatial position of each underwater probe in the electric field response spatial data table, the amplitude, phase and angle of arrival of the underwater probe are collected sequentially according to the position order, imported into the neural network model to reconstruct the electric field image, and output the direction coordinate sequence of the metal pipeline.

[0007] As a further embodiment of the present invention, the target excitation parameter set includes the amplitude of the radiated electromagnetic field signal and the frequency of the excitation signal; the transmitted electrical signal sequence specifically includes atomic energy level change data, electric field induction characteristic quantities, and signal transmission amplitude; the perturbation phase dataset includes the transmission phase change caused by energy level displacement, phase drift characteristics, and interference fringe position information; the electric field response spatial data table specifically includes the underwater probe spatial coordinates, electric field response amplitude, electric field response phase, and electric field response frequency; and the direction coordinate sequence of the metal pipeline specifically represents the spatial path of the metal pipeline.

[0008] As a further aspect of the present invention, the step of obtaining the target excitation parameter set specifically includes: S111: Apply an alternating electrical signal with a frequency range of 10kHz to 10MHz to the target pipeline through the transmitter, collect the instantaneous power waveform sequence generated by the metal pipeline after excitation, calculate the amplitude of the radiated electromagnetic field signal corresponding to the instantaneous power waveform sequence, and combine it with the frequency of the currently applied excitation signal to obtain the amplitude of the excitation frequency response signal. S112: Set the frequency adjustment step size in the frequency range of 10kHz to 10MHz, cyclically adjust the frequency of the excitation signal output by the transmitter source and repeatedly perform signal application and amplitude calculation, integrate the amplitude values ​​of multiple excitation frequency response signals obtained at each excitation frequency, and establish a multi-frequency electromagnetic radiation sequence. S113: Call up all excitation signal frequencies and corresponding radiated electromagnetic field signal amplitudes in the multi-frequency electromagnetic radiation sequence, arrange them in numerical order according to the excitation signal frequencies, and form a target excitation parameter set.

[0009] As a further aspect of the present invention, the step of obtaining the transmission electrical signal sequence specifically comprises: S211: The target excitation parameter set is called to excite the induced current in the seabed underground target detection area. The underwater probe with a sealed alkali metal steam pool and an optical window is deployed in the target detection area to measure the atomic energy level changes caused by the alternating electric field. The transmitted light signal output by the atomic transition behavior in the steam pool window is quantified to obtain the atomic transition response light intensity. S212: The intensity of the atomic transition response light is output from the optical window of the underwater probe and transmitted to the photoelectric detection end through the optical fiber path. The optical signal is continuously monitored during the transmission process, and all signal forms of the optical signal at the photoelectric detection end are recorded to obtain the optical fiber back-transmitted optical signal spectrum. S213: Based on the optical signal spectrum transmitted back through the optical fiber, photoelectric conversion processing is performed at the photoelectric detection end to convert the change relationship of the received optical signal intensity over time into an amplitude sequence of electrical signals, thereby obtaining a transmission electrical signal sequence.

[0010] As a further aspect of the present invention, the underwater probe is filled with rubidium atoms or cesium atoms.

[0011] As a further aspect of the present invention, the step of obtaining the perturbation phase dataset specifically includes: S311: Using an optical excitation signal group, the pump light and the probe light are used to irradiate the alkali metal vapor cell in the underwater probe, which sequentially excites the alkali metal atoms to transition from the ground state to the excited state and then to the Rydberg state, forming a transmission spectrum; S312: The transmission spectrum is transmitted to the photodetector and sampled to obtain multiple time-series transmission spectrum data. Multiple characteristic parameters such as the position of the electromagnetic induction transparent window, peak shift, and Autler-Townes split width in the spectrum are extracted to establish a spectral response sequence. S313: Analyze the mapping relationship between each characteristic parameter in the spectral response sequence and the atomic energy level displacement, calculate the intensity and phase of the external electric field, and construct a perturbation phase dataset.

[0012] As a further aspect of the present invention, the step of obtaining the electric field response spatial data table specifically includes: S411: Call the transmitted electrical signal sequence and the disturbance phase dataset, use a local reference signal source to perform frequency mixing processing on the transmitted electrical signal sequence to construct a different frequency detection path, and perform demodulation on the processed signal and the disturbance phase dataset to extract the electric field response amplitude and electric field response phase of each underwater probe at the excitation frequency to obtain the demodulated transmission component. S412: Acquire the three-dimensional spatial position information of each underwater probe, and according to the demodulated transmission components, pair the position information of each probe with the corresponding amplitude response value and instantaneous phase value of the transmission electrical signal, bind the position information with the transmission parameters, and generate position-bound transmission parameters. S413: Based on the positions of all underwater probes, bind the transmission parameters and the three-dimensional spatial positions of the underwater probes after frequency conversion and demodulation processing to form an electric field response spatial data table.

[0013] As a further aspect of the present invention, the step of obtaining the routing coordinate sequence of the metal pipeline specifically includes: S511: Collect the amplitude, phase, and angle of arrival between the incident direction of the electromagnetic wave and the internal reference direction of the sensor for each underwater probe in the electric field response spatial data table; combine the amplitude, phase, and angle of arrival for each probe to construct an input sample vector set. S512: Import the data in the input sample vector set into the neural network model to reconstruct the electric field image, and perform image interpolation on the spatial region with a sampling interval greater than 10 cm in the image to complete the signal between sparse measurement points and obtain a complete reconstructed electric field image. S513: Identify the continuous response region of the metal pipeline in the complete reconstructed electric field map where the electric field strength is higher than the preset discrimination threshold, aggregate the coordinates of all spatial reconstruction data in the response region, arrange the aggregated coordinate points in order, and output the direction coordinate sequence of the metal pipeline.

[0014] As a further aspect of the present invention, the process of coordinate aggregation of all spatial reconstruction data within the response area specifically involves calculating the geometric center points of the response area on multiple cross-sections and connecting the coordinates of all geometric center points to form the direction coordinate sequence of the metal pipeline.

[0015] A Rydberg electric field meter electromagnetic induction method submarine underground cable detection system, wherein the Rydberg electric field meter electromagnetic induction method submarine underground cable detection system is used to perform the above-mentioned Rydberg electric field meter electromagnetic induction method submarine underground cable detection method, the system comprising: The alternating excitation parameter construction module applies an alternating electrical signal to the target pipeline through a transmitter, causing electromagnetic radiation signals to be generated in the underground metal pipeline on the seabed. The amplitude of the radiated electromagnetic field signal is matched with the frequency of the corresponding applied excitation signal to construct the target excitation parameter set. The transmission electrical signal acquisition module excites the induced current in the seabed subsurface target detection area through the target excitation parameter set, and uses underwater probes deployed in the target detection area to measure the changes in atomic energy levels caused by the alternating electric field, forming a transmission electrical signal sequence. The atomic energy level sensing module uses a group of optical excitation signals to irradiate the alkali metal vapor pool in the underwater probe, which excites the energy level shift caused by the radio frequency electric field of the Rydberg state atoms and outputs a perturbation phase dataset. The electric field response data processing module performs frequency conversion and demodulation processing on the transmitted electrical signal sequence and the disturbance phase dataset, and binds the three-dimensional spatial position of the underwater probe after frequency conversion and demodulation processing with the transmission parameters to form an electric field response spatial data table. The electric field image reconstruction module obtains the amplitude, phase, and angle of arrival of each underwater probe in the electric field response spatial data table, and imports them as input sample vectors into the neural network model to reconstruct the electric field image, outputting the direction coordinate sequence of the metal pipeline.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are as follows: In this invention, by introducing direct measurement of the radio frequency electric field into the detection process, the weak electric field is sensed with high sensitivity using atomic energy level displacement and converted into an optical signal for transmission and demodulation. This effectively overcomes the problems of severe signal attenuation and noise interference in deep water or complex geological conditions of traditional electromagnetic induction equipment. It can detect submarine cables buried deeper or with weaker current signals. At the same time, the electric field response amplitude and phase information obtained through heterodyne demodulation are combined with spatial location information to construct electric field response data containing multi-dimensional physical characteristics. This changes the single criterion mode of relying solely on signal strength peak for positioning. By importing this multi-dimensional data into a neural network model for electric field image reconstruction, a more detailed spatial distribution of the electric field around the cable can be restored. Even with sparse measurement points, a continuous pipeline route can be generated, significantly improving the accuracy of cable positioning and the continuity of path tracking. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the workflow of the present invention; Figure 2 This is a flowchart of step S1 of the present invention; Figure 3 This is a flowchart of step S2 of the present invention; Figure 4 This is a flowchart of step S3 of the present invention; Figure 5 This is a flowchart of step S4 of the present invention; Figure 6 This is a flowchart of step S5 of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] Please see Figure 1This invention provides a technical solution: a method for detecting submarine underground cables using the electromagnetic induction method with a Rydberg electric field meter, comprising the following steps: S1: By applying an alternating electrical signal to the target pipeline through the transmitter, electromagnetic radiation signals are generated in the underground metal pipeline on the seabed. The amplitude of the radiated electromagnetic field signal is matched with the frequency of the corresponding applied excitation signal to construct a target excitation parameter set. S2: The induced current in the seabed subsurface target detection area is excited by the target excitation parameter set, and the changes in atomic energy levels caused by the alternating electric field are measured to form a transmission electrical signal sequence; S3: Use the optical excitation signal group to irradiate the alkali metal vapor pool in the underwater probe to excite the Rydberg state atoms to sense the energy level shift caused by the radio frequency electric field and output the perturbation phase data set. S4: Perform frequency conversion and demodulation processing on the transmitted electrical signal sequence and the disturbance phase dataset, and bind the three-dimensional spatial position of the underwater probe after frequency conversion and demodulation processing with the transmission parameters to form an electric field response spatial data table; S5: Based on the three-dimensional spatial position of each underwater probe in the electric field response spatial data table, the amplitude, phase and angle of arrival of the underwater probe are collected in sequence according to the position order, imported into the neural network model to reconstruct the electric field image, and output the direction coordinate sequence of the metal pipeline. The target excitation parameter set includes the amplitude of the radiated electromagnetic field signal and the frequency of the excitation signal. The transmitted electrical signal sequence specifically includes atomic energy level change data, electric field induction characteristics, and signal transmission amplitude. The perturbation phase dataset includes the transmission phase change caused by energy level displacement, phase drift characteristics, and interference fringe position information. The electric field response spatial data table specifically includes the underwater probe spatial coordinates, electric field response amplitude, electric field response phase, and electric field response frequency. The metal pipeline routing coordinate sequence specifically includes the spatial path of the metal pipeline.

[0020] Please see Figure 2 The specific steps for obtaining the target stimulus parameter set are as follows: S111: Apply an alternating electrical signal with a frequency range of 10kHz to 10MHz to the target pipeline through the transmitter, collect the instantaneous power waveform sequence generated by the metal pipeline after excitation, calculate the amplitude of the radiated electromagnetic field signal corresponding to the instantaneous power waveform sequence, and combine it with the frequency of the currently applied excitation signal to obtain the amplitude of the excitation frequency response signal. The transmitter applies a pure sinusoidal alternating electrical signal to the target pipeline via a contact probe holder. The initial signal frequency is 10 kHz. After the signal is applied, a magnetic field induction coil deployed at a predetermined monitoring location on the pipeline begins to collect the electromagnetic field radiated outward by the pipeline after excitation, and converts the induced magnetic field intensity change into a continuous voltage signal. The voltage signal is sampled by an analog-to-digital converter at a sampling rate much higher than the excitation signal frequency to ensure that the complete shape of the voltage waveform is captured without distortion, thereby generating a sequence composed of discrete voltage values ​​arranged in chronological order. Then, the sequence is analyzed... The voltage values ​​are squared to obtain a sequence of values ​​proportional to the instantaneous power, which is the instantaneous power waveform sequence. To calculate the amplitude of the radiated electromagnetic field signal corresponding to the instantaneous power waveform sequence, a portion corresponding to at least one complete signal period is extracted from the sequence. All instantaneous power ratio values ​​in this portion are summed and then divided by the total number of values ​​to obtain the average value. Finally, the square root operation is performed on the average value, and the result is the amplitude of the radiated electromagnetic field signal. Finally, the calculated amplitude of the radiated electromagnetic field signal is combined with the currently applied 10 kHz excitation frequency to form a data pair to obtain the excitation frequency response signal amplitude.

[0021] S112: Set the frequency adjustment step size in the frequency range of 10kHz to 10MHz, cyclically adjust the frequency of the excitation signal output by the transmitter, and repeatedly perform signal application and amplitude calculation. Integrate the amplitude values ​​of multiple excitation frequency response signals obtained at each excitation frequency to establish a multi-frequency electromagnetic radiation sequence. A frequency adjustment step size is set within the 10kHz to 10MHz frequency range. This step size is based on prior analysis of the pipeline material, diameter, and electromagnetic parameters of the surrounding soil medium. This analysis is used to predict the frequency bands where electromagnetic response peaks may occur. A fine-grained step size is set near the predicted peak frequency band to accurately capture response changes. A coarse-grained step size is set in frequency bands with gentle responses. If no prior analysis is available, a rapid frequency sweep with a large step size is performed first to identify frequency bands where the rate of change in response amplitude exceeds a preset threshold. This threshold is set above the average fluctuation level of the measured background noise to ensure that the identified changes are significant signal responses. For non-random noise, the identified frequency bands are then scanned with small step sizes. After setting the step size, the frequency of the excitation signal output by the transmitter is cyclically adjusted and the signal application and amplitude calculation are repeatedly performed. Specifically, after completing the measurement of the 10 kHz frequency, the excitation frequency is increased by one step value, and the complete signal application, power waveform sequence acquisition, and radiated electromagnetic field signal amplitude calculation are performed again to obtain a new excitation frequency response signal amplitude. This cyclic operation is repeated until the excitation frequency reaches and the measurement of the 100 kHz frequency point is completed. Then, the excitation frequency response signal amplitude data obtained at each different excitation frequency are collected to establish a multi-frequency electromagnetic radiation sequence.

[0022] S113: Call up all excitation signal frequencies and corresponding radiated electromagnetic field signal amplitudes in the multi-frequency electromagnetic radiation sequence, arrange them in numerical order according to the excitation signal frequencies, and form a target excitation parameter set; The multi-frequency electromagnetic radiation sequence is invoked. This sequence contains disordered data pairs consisting of excitation frequencies and corresponding electromagnetic field signal amplitudes. To form the target excitation parameter set, all data pairs in the sequence need to be arranged according to the numerical order of the excitation signal frequencies. The arrangement process is as follows: First, search for the data pair with the lowest frequency value in the sequence and take it as the first element of the new sequence; then, continue to search for the data pair with the lowest frequency value in the remaining data pairs and take it as the second element of the new sequence; repeat this search and placement process until all data pairs in the original sequence are placed into the new sequence in order of frequency value from low to high. The final ordered data set with monotonically increasing frequency is the target excitation parameter set.

[0023] Please see Figure 3 The specific steps for obtaining the transmission electrical signal sequence are as follows: S211: The target excitation parameter set is called to excite the induced current in the seabed underground target detection area. The underwater probe, which is set up in the target detection area and contains a sealed alkali metal steam pool and an optical window, measures the changes in atomic energy levels caused by the alternating electric field. The transmitted light signal output by the atomic transition behavior in the steam pool window is quantified to obtain the atomic transition response light intensity. The underwater probe is filled with rubidium atoms or cesium atoms. The target excitation parameter set is invoked, and the transmitters are driven sequentially according to their frequency order to apply excitation to the pipeline in the seabed subsurface target detection area. The resulting induced current forms an alternating electric field around the pipeline with the same excitation frequency. At this point, the underwater probe begins to operate. When the rubidium or cesium atoms filling the probe sense the external alternating electric field, their inherent atomic energy levels undergo a Stark effect shift. Simultaneously, a beam of probe light with a frequency precisely locked to a specific atomic transition spectral line passes through the steam pool (this spectral line is pre-selected based on the type of alkali metal atoms used, and its corresponding transition is highly sensitive to external electric fields and easily achievable using commercial lasers). The shift in atomic energy levels changes the probability of the atoms absorbing the probe light, thus altering the intensity of the transmitted light after passing through the steam pool. This transmitted light, carrying information about the atomic transitions, is the atomic transition response light intensity, which is output from the optical window of the underwater probe.

[0024] S212: The light intensity of the atomic transition response is output from the optical window of the underwater probe and transmitted to the photoelectric detection end through the optical fiber path. The optical signal is continuously monitored during the transmission process, and all signal forms of the optical signal at the photoelectric detection end are recorded to obtain the optical signal spectrum transmitted back through the optical fiber. The light intensity of the atomic transition response, carrying information about atomic transitions, is exported from the optical window of the underwater probe and coupled into a connected optical fiber. The optical signal travels along the fiber path from the seabed to a photodetector on the surface. At the photodetector, a highly sensitive detector, such as a photodiode, continuously monitors the transmitted optical signal, converting the number of received photons into a specific current or voltage value in real time. Data acquisition equipment records the instantaneous values ​​of the electrical signals output by the photodetector at fixed high-frequency time intervals (the time interval is set to be much smaller than one-tenth of the fastest change period of the measured signal to ensure sufficient sampling of the signal's dynamic process). By collecting all the time-series recorded signal values, the complete waveform and spectral characteristics of the signal intensity changing over time can be depicted, thus obtaining the optical fiber-returned signal spectrum.

[0025] S213: Based on the optical fiber back-transmitted optical signal spectrum, photoelectric conversion processing is performed at the photoelectric detection end to convert the change relationship of the received optical signal intensity over time into an amplitude sequence of electrical signals, thereby obtaining a transmission electrical signal sequence; This process precisely converts the change in optical signal intensity over time into an amplitude sequence of electrical signals. Specifically, the optical signal in the optical fiber's back-transmitted optical signal spectrum first illuminates the photosensitive surface of a photomultiplier tube or avalanche photodiode. The photoelectric device linearly converts the light intensity value at each moment into a current signal with a larger amplitude range through an internal multiplication amplification process. Subsequently, a high-speed analog-to-digital converter samples this continuously changing current signal at equal intervals, converting the analog current quantity at each sampling moment into a binary number with a specific bit width. The bit width of the binary number is determined based on the expected dynamic range of the signal and the required signal-to-noise ratio to maximize quantization accuracy without signal clipping. All these binary numbers arranged in chronological order together form the final transmitted electrical signal sequence.

[0026] Please see Figure 4 The specific steps for obtaining the perturbation phase dataset are as follows: S311: Using an optical excitation signal group, the pump light and the probe light are used to irradiate the alkali metal vapor cell in the underwater probe, which sequentially excites the alkali metal atoms to transition from the ground state to the excited state and then to the Rydberg state, forming a transmission spectrum; Using an optically excited signal array, the process begins with precise frequency locking of the probe laser. A 780.24 nm laser beam is stabilized at the resonant frequency of the transition of rubidium (Rb) atoms from the ground state 5S1 / 2 to the intermediate excited state 5P3 / 2 using saturable absorption spectroscopy. The intensity of this probe laser is maintained at a low level to avoid saturation. Subsequently, the frequency of another strongly coupled laser beam with a wavelength of 480.15 nm is locked at the transition from the intermediate excited state 5P3 / 2 to the target highly excited Rydberg state 50D5 / 2. Both laser beams are then passed through the same polarization-maintaining electrode. The optical fiber transmits the light to the underwater probe. Inside the probe, in an alkali metal vapor cell, the probe light and the coupling light are precisely spatially superimposed in a counter-propagation manner, forming a three-level ladder atomic system. Under the influence of the strong coupling light field, quantum interference occurs between the ground state and the Rydberg state. This results in a transmission window with an extremely narrow width appearing at the center of the absorption peak that originally corresponds to the transition from the ground state to the excited state in the absorption spectrum of the probe light. This is the electromagnetic induction transparent window. At this time, the atoms are effectively prepared in a coherent dark state, and the absorption of the probe light is suppressed. The intensity of the probe light after passing through the atomic vapor is the transmission spectrum.

[0027] S312: Transmit the transmission spectrum to the photodetector and sample it to obtain transmission spectrum data of multiple time series. Extract multiple characteristic parameters in the spectrum, such as the position of the electromagnetic induction transparent window, peak shift, and Autler–Townes split width, and establish a spectral response sequence. The transmission spectral signal carrying atomic response information is fed back to the photodetector. After photoelectric conversion and analog-to-digital conversion, it is discretized at a sampling rate of 1 MS / s to obtain a series of discrete voltage values ​​characterizing the transmitted light intensity, i.e., sequential transmission spectral data. To extract spectral feature parameters, a reference transmission spectrum is first obtained by scanning the probe laser frequency under conditions without an external radio frequency electric field. The Lorentz linear fitting algorithm is then applied to this spectral data to determine the center frequency of the fitted peak as the initial position of the electromagnetic induction transparent window. And store it, at each sampling time after the applied radio frequency electric field to be measured. The transmission spectrum was reacquired, and the Lorentz linear fitting algorithm was used again to determine the new peak center position. Peak drift is calculated as Simultaneously, multi-peak detection is performed on the current spectral data. Specifically, the first and second derivatives of the spectral data are calculated, and the number of peaks is determined based on the correspondence between the zeros of the second derivative and the extrema of the first derivative. If a single peak is detected, the Autler–Townes splitting width is determined. If the value is assigned to zero, and two peaks are detected, the data is fitted using a double Lorentz peak fitting function to extract the center frequencies of the two sub-peaks. and And the Autler–Townes split width is calculated as The three parameters acquired at each moment—the position of the electromagnetic induction transparent window, the peak drift, and the Autler–Townes split width—are integrated into a feature vector and arranged in time sequence to establish a spectral response sequence.

[0028] S313: Analyze the mapping relationship between each characteristic parameter in the analytical spectral response sequence and the atomic energy level displacement, calculate the intensity and phase of the external electric field, and construct a perturbation phase dataset; By analyzing the optical harmonic response sequence and the close relationship between the characteristic parameters at each time point and the atomic energy level positions, the intrinsic correlation of the electric field effect is revealed. The peak shift of the electromagnetic response window, the Autler-Townes effect, is perceived and converted into a delta-level quantization quantity, which is positively correlated with the average value of the external electric field. The index phase position generated by the external electric field is interpreted using frequency detection technology. The phase information of the microwave signal under test is additionally obtained by referencing the local oscillator signal. The optical signal (microwave band) provided by the local oscillator is mixed with the microwave signal under test at near-in-phase frequencies. The intensity of the mixed microwave signal carries the phase difference between the signal under test and the local signal. This signal carrying the phase difference information is converted into an electrical signal by a photodetector and then further processed based on the in-phase components of the electrical signal. and orthogonal components The following phase analysis function is called to calculate the value of the perturbation phase change: ,in, To be at the sampling time Radiated electric field of submarine cables The perturbation phase caused by this perturbation, demodulated in the atomic ensemble response, is the core parameter to be solved. (The letter is...) Represents the phase angle, subscript This indicates that the phase is induced by an external electric field, as specified in parentheses. This indicates that the phase is time. The function corresponds to each discrete sampling time point in step S312 when the time-series spectral data is acquired. The amplitude of the in-phase component signal is represented by the letter. Represents signal, subscript Representing in-phase, it is obtained by directly mixing the electrical signal output from the photodetector with the reference local oscillator signal, and then passing it through a low-pass filter to obtain a DC or slowly varying voltage signal. The amplitude of the quadrature component signal is indicated by the subscript. The orthogonality is represented by the following method: the electrical signal output from the photodetector is mixed with a reference local oscillator signal that has undergone a 90-degree phase shift, and then the result is a voltage signal obtained by passing it through a low-pass filter. The arctangent function is calculated based on the x-coordinate of a point in a rectangular coordinate system. ) and ordinate ( Calculate the angle between the line connecting this point and the origin along the positive horizontal axis. This angle is used here to recover the phase information of the original signal from two mutually orthogonal signal components, at a given sampling time. For example, after mixing and low-pass filtering, the actual measured amplitude of the in-phase component signal... The amplitude of the quadrature component signal is 0.351V. The value is 0.192V. Substituting the measured value into the phase analysis function, the calculation is performed first. and The ratio: Then, an arctangent operation is performed on this ratio to solve for the phase angle: The advantage of the rad formula is that by performing orthogonal demodulation in classical signal processing on the optical readout signal of the atomic quantum state, the direct measurement of the phase of the weak electric field is transformed into the measurement of two DC voltage components. This phase analysis function is repeatedly executed on the spectral response sequence data at each sampling time point to generate a series of discrete perturbation phase change values ​​and construct a perturbation phase dataset.

[0029] Please see Figure 5 The specific steps for obtaining the electric field response spatial data table are as follows: S411: Call the transmitted electrical signal sequence and the disturbance phase dataset, use the local reference signal source to perform frequency mixing processing on the transmitted electrical signal sequence to construct the heterogeneous frequency detection path, and perform demodulation on the processed signal and disturbance phase dataset to extract the electric field response amplitude and electric field response phase of each underwater probe at the excitation frequency to obtain the demodulated transmission component. First, a local reference signal source is activated. This source generates a sinusoidal electrical signal with a frequency higher than the current excitation signal frequency by a fixed difference. The fixed difference is chosen to shift the signal to a low-noise frequency band. The frequency needs to be low enough for subsequent digital filtering, while also being high enough to avoid the sensor's zero-frequency drift region; for example, it is set to 1 kHz. Next, frequency conversion and demodulation are performed. The process is as follows: First, the transmission electrical signal sequence from the photoelectric conversion module and the sinusoidal electrical signal from the local reference signal source are simultaneously input to two ports of an electronic mixer. The electronic mixer multiplies the instantaneous voltage values ​​of the two input signals. According to the trigonometric function product rule, its output signal will simultaneously contain two new frequency components: one is the sum of the input signal frequency and the local reference signal frequency (sum frequency), and the other is the difference between the two frequencies (difference frequency). The frequency of the difference frequency is the preset 1 kHz, thus completing the frequency conversion. Demodulation is then performed. The signal output from the mixer is fed into a low-pass filter with a cutoff frequency set slightly above 1 kHz, such as 1100 Hz. This setting ensures that the 1 kHz difference frequency signal can pass through without attenuation, while sum frequency components and other high-frequency noise at frequencies much higher are effectively filtered out. After filtering, only the difference frequency signal carrying the original signal amplitude information and stable at 1 kHz is retained. Finally, envelope detection is performed on this clean difference frequency signal. The envelope detector uses a fast-response rectifier circuit and a slow-response smoothing filter circuit to extract the slowly changing profile of the difference frequency signal amplitude. This profile is the amplitude response value of the transmitted electrical signal at the excitation frequency. Simultaneously, the instantaneous phase value that perfectly matches the current demodulation time point is found and extracted from the perturbation phase dataset. Finally, the amplitude response value of the transmitted electrical signal and the instantaneous phase value are combined as a data pair to obtain the demodulated transmitted component.

[0030] S412: Acquire the three-dimensional spatial position information of each underwater probe, and pair the position information of each probe with the corresponding amplitude response value and instantaneous phase value of the transmitted electrical signal according to the demodulated transmission components, bind the position information with the transmission parameters, and generate position-bound transmission parameters. By deploying a network of underwater acoustic positioning base stations in the detection area, acoustic interrogation signals are transmitted to each underwater probe and its response signals are received. The three-dimensional spatial position information of each underwater probe relative to the origin of the preset seabed coordinate system is calculated based on the time difference of signal propagation. The positioning process needs to achieve a high accuracy sufficient to resolve minute changes in the pipeline path. Based on the demodulated transmission components obtained in the previous step, the three-dimensional spatial position information of each probe is paired with the amplitude response value and instantaneous phase value of the transmitted electrical signal demodulated from the probe signal. The specific pairing operation is to create a data record containing five fields: three fields are used to store the x, y, and z coordinate values ​​of the probe, and the other two fields are used to store the corresponding amplitude response value and instantaneous phase value of the transmitted electrical signal, respectively. By generating such a data record for each probe, the binding of position information and transmission parameters is realized, generating position-bound transmission parameters.

[0031] S413: Bind transmission parameters according to the position of all underwater probes, bind the three-dimensional spatial position of the underwater probes after frequency conversion and demodulation processing with transmission parameters to form an electric field response spatial data table; Based on the location-bound transmission parameters of all underwater probes, these scattered data records are aggregated and organized. Specifically, a data processing program initializes a structured dataset with a logical structure of a two-dimensional table. The column headers are predefined as: Probe ID, X-coordinate, Y-coordinate, Z-coordinate, amplitude response, and phase response. The program then iterates through all location-bound transmission parameter records generated in the previous step. For each probe's record, the program reads its five core data points (x, y, z coordinates, amplitude, and phase) and creates a new row in the table, sequentially filling these data into the corresponding columns. This process is repeated until all probe data has been added. In this way, the originally scattered data records, each representing a single probe, are integrated into a single, well-organized data table. Each row in the table completely describes all the information of a spatial detection point. This dataset closely links the geometric location information of all probes with their measured electric field response physical quantities, forming a comprehensive spatial data table describing the spatial distribution characteristics of the electric field.

[0032] Please see Figure 6 The specific steps for obtaining the coordinate sequence of the metal pipeline's routing are as follows: S511: Collect the amplitude, phase, and angle of arrival between the incident direction of the electromagnetic wave and the internal reference direction of the sensor for each underwater probe in the electric field response spatial data table. Combine the amplitude, phase, and angle of arrival for each probe to construct an input sample vector set. The angle of arrival is obtained by setting up a miniaturized triaxial orthogonal magnetic field antenna array inside each probe. By comparing the amplitude and phase difference of the signals received by the antennas along different axes, the azimuth and elevation angles between the incident direction of the electromagnetic wave and the preset reference coordinate axis inside the probe are resolved. The four values ​​of amplitude, phase, azimuth and elevation angle corresponding to each probe are combined to form a four-dimensional vector. The four-dimensional vectors generated by all probes are collected together to construct an input sample vector set for subsequent processing.

[0033] S512: Import the data in the input sample vector set into the neural network model to reconstruct the electric field image, and perform image interpolation on the spatial region with a sampling interval greater than 10 cm in the image to complete the signal between sparse measurement points and obtain a complete reconstructed electric field image; The data from the input sample vector set is imported into a pre-trained deep neural network model to reconstruct the electric field image. The neural network model adopts an encoder-decoder structure. Its training dataset is a pre-set library generated by performing extensive finite element simulations on the electromagnetic field distribution of various possible pipeline routes, depths, and materials in a simulated seabed environment. Structurally, the encoder consists of a series of convolutional and pooling layers, used to compress the input sparse probe data vector and extract deep spatial feature maps. The decoder consists of a series of deconvolutional layers (or transposed convolutional layers) and upsampling layers, progressively enlarging the feature map output by the encoder to restore it to the full grid resolution of the target 3D space. Skip connections are set between decoders to directly pass the shallow feature maps of the encoder to the corresponding layers of the decoder to preserve fine electric field details. During model execution, the input sample vector set is fed into the encoder for forward propagation, and after feature extraction and compression, it is upsampled and fused by the decoder. Finally, a complete reconstructed electric field map with predicted electric field intensity values ​​at each point on a fine three-dimensional grid is output. Subsequently, image interpolation is performed on regions in the image where the distance between any two adjacent valid data points is greater than the preset target spatial resolution. The interpolation process is based on the physical laws of electromagnetic fields. The signals between sparse measurement points are supplemented by solving the Laplace equation or Helmholtz equation for the region between measurement points to obtain a complete reconstructed electric field map.

[0034] S513: Identify the continuous response region of the metal pipeline where the electric field strength in the complete reconstructed electric field map is higher than the preset discrimination threshold, aggregate the coordinates of all spatial reconstruction data in the response region, arrange the aggregated coordinate points in order, and output the direction coordinate sequence of the metal pipeline. Specifically, the process of aggregating the coordinates of all spatial reconstruction data in the response region is to calculate the geometric center point of the response region on multiple cross sections and connect the coordinates of all geometric center points to form the direction coordinate sequence of the metal pipeline. The identification process begins by statistically analyzing all electric field intensity values ​​in the fully reconstructed electric field map, calculating their mean and standard deviation. The electric field intensity discrimination threshold is set to the mean plus three times the standard deviation, based on the 3-sigma principle of normal distribution. This setting can separate abnormally strong signal regions from background noise with high confidence. All continuous spatial voxels with electric field intensity values ​​exceeding this threshold are aggregated to form a three-dimensional response region. Next, the coordinates of all spatial reconstruction data within the response region are aggregated. Specifically, the aggregation process involves first determining the approximate extension direction of the response region as the principal axis, and then generating a series of two-dimensional cross-sections at fixed intervals along a direction perpendicular to the principal axis. The interval must be smaller than the expected minimum radius of curvature of the pipeline path to ensure that no curved sections of the pipeline are missed. For each cross-section, the coordinates of the geometric center points of all voxels at the intersection of the response region and the cross-section are calculated using the formula... To execute, in this formula, Representing the The three-dimensional coordinates of the geometric center point on each cross section are a point in the final pipeline routing coordinate sequence; It is an index that counts all cross sections, starting from 1 and incrementing; Indicates the first Within a cross-section, the total number of voxels whose field strength values ​​are higher than the preset field strength discrimination threshold; It is in the Inside the cross-section, for this An index for counting individual voxels; It is the summation symbol, indicating that the summation of the first and second hexagrams is performed. Within each cross section, from the first to the second... The coordinate components of all high field strength voxels are summed separately. , , Representing respectively in the The first cross-section The x, y, and z components of the three-dimensional spatial coordinates of each high-field-strength voxel are derived from the three-dimensional spatial grid of the fully reconstructed electric field map. The calculation logic of the entire formula is as follows: for each cross section, the average values ​​of the x, y, and z coordinates of all high-response voxels within it are calculated independently. These three average values ​​together constitute the best estimate of the pipeline position on the cross section, i.e., the geometric center point. Finally, the coordinates of the calculated geometric center points on all cross sections are arranged and connected according to their order on the principal axes. The output ordered set of coordinate points is the direction coordinate sequence of the metal pipeline. Calculation process demonstration: To illustrate the specific calculation process, a demonstration scenario is set: Step 1: Based on the analysis results of the fully reconstructed electric field map. Assume that the 8th cross section (i.e., After filtering by the field strength threshold, it was found that the field strength values ​​of 3 spatial voxels within this cross-section exceeded the threshold, therefore the total number of voxels was [not specified]. The value is 3. These three high-field-strength voxels completely reconstruct the electric field. Figure 3 The coordinates in the 1D space grid are as follows: voxel 1 ( ):( , , ) = (25.2, 80.5, -15.4), voxel 2 ( ):( , , =(24.9, 80.5, -15.7), voxel 3 ( ):( , , = (25.5, 80.5, -15.6). Second step: Summate the x, y, and z coordinate components separately: Sum of x coordinates = The sum of the y-coordinates = The sum of the z coordinates = Step 3: Divide the sum of each component by the total number of voxels. Center point x-coordinate = The y-coordinate of the center point = The z-coordinate of the center point = Calculate the coordinates of the geometric center point of the 8th cross-section. The coordinates are (25.2, 80.5, -15.57). This coordinate point is considered as an estimate of the center position of the pipeline on the cross-section and is added to the coordinate sequence of the pipeline's orientation.

[0035] A Rydberg electric field meter electromagnetic induction method submarine underground cable detection system, used to perform the aforementioned Rydberg electric field meter electromagnetic induction method for submarine underground cable detection, the system includes: The alternating excitation parameter construction module applies an alternating electrical signal to the target pipeline through a transmitter, causing electromagnetic radiation signals to be generated in the underground metal pipeline on the seabed. The amplitude of the radiated electromagnetic field signal is matched with the frequency of the corresponding applied excitation signal to construct the target excitation parameter set. The transmission electrical signal acquisition module excites the induced current in the seabed subsurface target detection area through the target excitation parameter set, and uses underwater probes deployed in the target detection area to measure the changes in atomic energy levels caused by the alternating electric field, forming a transmission electrical signal sequence; The atomic energy level sensing module uses a group of optical excitation signals to irradiate the alkali metal vapor pool in the underwater probe, which excites the energy level shift caused by the radio frequency electric field of the Rydberg state atoms and outputs a perturbation phase dataset. The electric field response data processing module performs frequency conversion and demodulation processing on the transmitted electrical signal sequence and the disturbance phase dataset, and binds the three-dimensional spatial position of the underwater probe after frequency conversion and demodulation processing with the transmission parameters to form an electric field response spatial data table. The electric field image reconstruction module obtains the amplitude, phase, and angle of arrival of each underwater probe in the electric field response spatial data table. These are used as input sample vectors to import into the neural network model to reconstruct the electric field image, and output the direction coordinate sequence of the metal pipeline.

[0036] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method of detecting a subsea buried cable by the method of electromagnetic induction of a Rydberg electric field meter, characterised in that, The method comprises the following steps: S1: applying an alternating electric signal to the target pipeline through a transmitting source to generate an electromagnetic radiation signal in the metal pipeline under the seabed, pairing the amplitude of the radiation electromagnetic field signal with the corresponding applied excitation signal frequency to construct a target excitation parameter set; S2: exciting the induced current of the target detection area under the seabed through the target excitation parameter set, and measuring the atomic energy level change caused by the alternating electric field to form a transmission electric signal sequence; S3: irradiating the alkali metal vapor cell in the underwater probe with a light excitation signal group to excite the Rydberg state atom to perceive the energy level displacement change caused by the radio frequency electric field, and output a perturbation phase data set; S4: performing heterodyne conversion and demodulation processing on the transmission electric signal sequence and the perturbation phase data set, binding the three-dimensional spatial position of the underwater probe after heterodyne conversion and demodulation processing with the transmission parameters to form an electric field response spatial data table; S5: according to the three-dimensional spatial position of each underwater probe in the electric field response spatial data table, sequentially collecting the amplitude, phase and arrival angle of the position where the underwater probe is located in the order of position, importing the neural network model to reconstruct the electric field image, and outputting the coordinate sequence of the metal pipeline.

2. The Rydberg field-meter electromagnetic induction method subsea buried cable detection method of claim 1, wherein, The target excitation parameter set comprises the radiation electromagnetic field signal amplitude and the excitation signal frequency, the transmission electric signal sequence specifically comprises the atomic energy level change data, the electric field induction characteristic quantity and the signal transmission amplitude, the perturbation phase data set comprises the transmission phase change caused by the energy level displacement, the phase drift characteristic and the interference fringe position information, the electric field response spatial data table specifically comprises the underwater probe spatial coordinates, the electric field response amplitude, the electric field response phase and the electric field response frequency, and the coordinate sequence of the metal pipeline specifically comprises the spatial path of the metal pipeline.

3. The Rydberg field-meter electromagnetic induction method subsea buried cable detection method of claim 1, wherein, The acquisition step of the target excitation parameter set specifically comprises: S111: applying a frequency alternating electric signal with a frequency range of 10 kHz to 10 MHz to the target pipeline through a transmitting source, collecting the instantaneous power waveform sequence generated after the metal pipeline is excited, calculating the radiation electromagnetic field signal amplitude corresponding to the instantaneous power waveform sequence, and combining the excitation signal frequency to obtain the excitation frequency response signal amplitude; S112: setting a frequency adjustment step in the frequency interval of 10 kHz to 10 MHz, cyclically adjusting the excitation signal frequency output by the transmitting source and repeatedly executing the signal application and amplitude calculation, integrating the excitation frequency response signal amplitudes obtained under each excitation frequency to establish a multi-frequency point electromagnetic radiation sequence; S113: calling all excitation signal frequencies and corresponding radiation electromagnetic field signal amplitudes in the multi-frequency point electromagnetic radiation sequence, arranging them in numerical order according to the excitation signal frequency to form a target excitation parameter set.

4. The Rydberg field-meter electromagnetic induction method subsea buried cable detection method of claim 3, wherein, The acquisition step of the transmission electric signal sequence specifically comprises: S211: calling the target excitation parameter set to excite the induced current of the target detection area under the seabed, using the underwater probe with a sealed alkali metal vapor cell and an optical window arranged in the target detection area to measure the atomic energy level change caused by the alternating electric field, and quantifying the transmission light signal output by the atomic transition behavior at the vapor cell window to obtain the atomic transition response light intensity; S212: output the atomic transition response light intensity from the optical window of the underwater probe, transmit it to the photodetection probe end through the optical fiber path, continuously monitor the optical signal in the transmission process, record the entire signal form of the optical signal at the photodetection probe end, and obtain the optical fiber backhaul optical signal spectrum; S213: based on the optical fiber backhaul optical signal spectrum, perform photoelectric conversion processing at the photodetection probe end, convert the received light signal intensity-time variation relationship into an amplitude sequence of an electric signal, and obtain a transmission electric signal sequence.

5. The Rydberg field-meter electromagnetic induction method subsea buried cable detection method according to claim 4, characterized in that, The underwater probe is filled with rubidium atoms or cesium atoms.

6. The Rydberg field-meter electromagnetic induction method subsea buried cable detection method of claim 4, wherein, The obtaining step of the perturbation phase data set is specifically: S311: Use the optical excitation signal group to irradiate the alkali metal vapor cell in the underwater probe with pump light and probe light, sequentially excite the alkali metal atoms from the ground state to the excited state and then to the Rydberg state, and form a fiber transmission spectrum; S312: transmit the fiber transmission spectrum to the photodetector and sample it to obtain a plurality of time-series fiber transmission spectrum data, extract the electromagnetic induced transparency window position, peak shift, Autler-Townes splitting width and other characteristic parameters in the spectrum, and establish a spectrum response sequence; S313: analyze the mapping relationship between each characteristic parameter in the spectrum response sequence and the atomic energy level displacement, calculate the perturbation phase change value caused by the external electric field, and construct a perturbation phase data set.

7. The Rydberg field-meter electromagnetic induction method subsea buried cable detection method according to claim 6, characterized in that, The obtaining step of the electric field response space data table is specifically: S411: call the transmission electric signal sequence and the perturbation phase data set, use a local reference signal source to mix the transmission electric signal sequence to construct a heterodyne detection channel, demodulate the processed signal and the perturbation phase data set, extract the electric field response amplitude and the electric field response phase of each underwater probe at the excitation frequency, and obtain a demodulation transmission component; S412: obtain the three-dimensional spatial position information of each underwater probe, and according to the demodulation transmission component, pair the position information of each probe with the corresponding transmission electric signal amplitude response value and instantaneous phase value, bind the position information with the transmission parameters, and generate position-bound transmission parameters; S413: according to the position-bound transmission parameters of all underwater probes, bind the three-dimensional spatial position of the underwater probe after heterodyne conversion and demodulation processing with the transmission parameters to form an electric field response space data table.

8. The Rydberg field-meter electromagnetic induction method subsea buried cable detection method according to claim 7, characterized in that, The obtaining step of the metal pipeline orientation coordinate sequence is specifically: S511: collect the amplitude, phase and angle of arrival between the electromagnetic wave incident direction and the internal reference direction of the sensor at the spatial position of each underwater probe in the electric field response space data table, combine the amplitude, phase and angle of arrival corresponding to each probe, and construct an input sample vector set; S512: import the data in the input sample vector set into a neural network model to reconstruct an electric field image, perform image interpolation on the spatial regions with a sampling interval greater than 10 cm in the image, complete the signals between sparse measurement points, and obtain a complete reconstructed electric field image. S513: identifying a metal pipeline continuous area response region in which the electric field intensity in the complete reconstructed electric field map is higher than a preset discrimination threshold, aggregating the coordinates of all spatial reconstruction data in the response region, arranging the aggregated coordinate points in order, and outputting a coordinate sequence of the metal pipeline.

9. The Rydberg field-meter electromagnetic induction method subsea buried cable detection method according to claim 8, characterized in that, The process of aggregating the coordinates of all spatial reconstruction data in the response region is specifically that geometric center points of the response region on multiple cross sections are calculated, and the coordinates of all the geometric center points are connected to form the coordinate sequence of the metal pipeline.

10. A Rydberg electric field meter electromagnetic induction method subsea buried cable detection system characterized by, The method for detecting a subsea underground cable by a Rydberg electric field meter electromagnetic induction method according to any one of claims 1-9, wherein the system comprises: An alternating excitation parameter construction module, which applies an alternating electric signal to the target pipeline through a transmission source to generate an electromagnetic radiation signal in the metal pipeline underground, pairs the amplitude of the radiated electromagnetic field signal with the corresponding applied excitation signal frequency to construct a target excitation parameter set; A transmission electric signal acquisition module, which excites an induced current in a target detection area underground by the target excitation parameter set, and measures the atomic energy level change caused by the alternating electric field by using an underwater probe arranged in the target detection area to form a transmission electric signal sequence; An atomic energy level sensing module, which irradiates an alkali metal vapor cell in the underwater probe with a light excitation signal group to excite Rydberg state atoms to sense the energy level displacement change caused by the radio frequency electric field and output a perturbation phase data set; An electric field response data processing module, which performs heterodyne conversion and demodulation processing on the transmission electric signal sequence and the perturbation phase data set, binds the three-dimensional spatial position of the underwater probe after the heterodyne conversion and demodulation processing with the transmission parameters to form an electric field response spatial data table; An electric field image reconstruction module, which obtains the amplitude, phase and angle of arrival of the spatial position of each underwater probe in the electric field response spatial data table as an input sample vector to import a neural network model to reconstruct an electric field image and output a coordinate sequence of the metal pipeline.

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