A superconducting transient electromagnetic continuous measurement system and method

Abstract

The application discloses a superconducting transient electromagnetic continuous measurement system and method, and belongs to the technical field of transient electromagnetic prospecting. The method comprises the following steps: controlling a superconducting magnetometer to collect static geomagnetic field data of a current measurement point in real time; comparing the measured geomagnetic field value with a preset magnetic field compensation threshold value, performing geomagnetic field compensation according to the comparison result, and enabling the superconducting magnetometer to maintain a locked state; in the locked state, transmitting an excitation signal according to a preset time sequence, and continuously collecting transient electromagnetic field decay curve original data of each measurement period in a non-superimposed single original data collection mode; monitoring the locked state and the geomagnetic field fluctuation amplitude in real time during the collection process, and eliminating current period abnormal data when lock loss or fluctuation exceeding the threshold value is detected; collecting position movement data in real time, identifying a measurement point switching action according to the position movement data, automatically updating geomagnetic field compensation parameters, returning to the aforementioned steps to realize continuous measurement.

Description

Technical Field

[0001] This invention relates to the field of transient electromagnetic exploration technology, and in particular to a superconducting transient electromagnetic continuous measurement system and method. Background Technology

[0002] Transient electromagnetic (TEM) is one of the core geophysical exploration methods in the fields of geological exploration, mineral exploration, and hydrogeological detection. Conventional TEM equipment acquires signals by observing induced electromotive force. Due to the weakness of the late-stage induced signal, it typically relies on multiple data superpositions to suppress noise and improve the signal-to-noise ratio. With the development of superconducting technology, superconducting magnetometers are gradually being applied in the field of TEM exploration. Compared with conventional induction coil sensors, superconducting magnetometers can directly observe magnetic field signals and have outstanding advantages such as high sensitivity, good low-frequency response, and strong late-stage detection capability. They can compensate for the shortcomings of conventional TEM, such as weak late-stage data and insufficient accuracy in deep detection, and have high application value in the field of deep geological exploration.

[0003] Currently, superconducting transient electromagnetic field measurements have been gradually implemented and applied. However, due to the sensitivity of superconducting sensors to the working magnetic field environment and the need to maintain a locked state for stable output, the industry still uses the traditional point-based superposition acquisition mode, and a dedicated acquisition method adapted to the measurement characteristics of superconducting magnetic fields has not yet been developed. The current common measurement process is as follows: using a single-point independent measurement mode, after the operator moves the equipment to a single measurement point, they manually operate the controller to modulate the compensation signal to cancel the geomagnetic field at the current measurement point, causing the superconducting magnetometer to briefly enter a locked stable state; within a limited stability window, transient electromagnetic attenuation curves are acquired multiple times, and noise is suppressed by superimposing multiple curves to obtain the final attenuation data for that measurement point; after the single-point measurement is completed, the equipment is stopped and the equipment is moved to the next measurement point, and the manual modulation and superposition acquisition steps are repeated to complete the profile measurement point by point.

[0004] The aforementioned point-based superposition measurement scheme has several shortcomings in practical applications. Regarding acquisition efficiency, it relies entirely on manual point-by-point debugging, manual locking, and switching measurement points during shutdowns, making continuous operation impossible. Field exploration procedures are cumbersome and time-consuming, making it unsuitable for the rapid exploration needs of large areas and long profiles. Regarding data quality, the superposition acquisition strategy is incompatible with the operating characteristics of the superconducting magnetometer. The superconducting magnetometer directly acquires magnetic field signals, resulting in strong amplitude and high native signal-to-noise ratio in later data, eliminating the need for superposition. Blindly superimposing data can mix in abnormal data caused by unstable manual modulation and brief sensor lock-offs. The more superpositions, the more severe the attenuation curve distortion, leading to data distortion in later stages. Regarding equipment stability, geomagnetic field cancellation and sensor locking rely entirely on manual adjustment, resulting in strong lag, poor modulation accuracy, and high subjectivity. In complex field magnetic field environments, frequent sensor lock-offs occur, the stable measurement window is short and unstable, and data acquisition is highly random and has poor repeatability. Furthermore, traditional overlay models cannot distinguish between normal data and unlocked anomalous data. By simply overlaying and averaging, anomalous data is retained and amplified, ultimately causing deviations in geological inversion results and affecting the accuracy of exploration.

[0005] In summary, existing point-based superposition measurement schemes are fundamentally incompatible with the working characteristics of superconducting magnetometers. Their acquisition efficiency, data accuracy, equipment stability, and automation levels are insufficient to meet the practical needs of deep geological exploration, thus hindering the large-scale field application of superconducting transient electromagnetic technology. Therefore, there is an urgent need for a superconducting transient electromagnetic measurement method that can automatically compensate for the geomagnetic field, employ a non-superposition acquisition mode, and support continuous switching of measurement points to overcome the aforementioned shortcomings of existing technologies. Summary of the Invention

[0006] The purpose of this invention is to provide a superconducting transient electromagnetic continuous measurement system and method. It addresses the shortcomings of existing superconducting transient electromagnetic point measurement and superposition methods, such as low acquisition efficiency, data distortion caused by superposition, and high dependence on manual intervention. By automatically compensating and locking the geomagnetic field, acquiring non-superposition continuous data, and automatically connecting continuous switching of measurement points, it achieves efficient, stable, and high-precision continuous measurement of superconducting transient electromagnetic field profiles.

[0007] To achieve the above objectives, the present invention provides a superconducting transient electromagnetic continuous measurement system, including a main controller, a superconducting magnetometer, a magnetic field compensation modulation module, a transient electromagnetic transmitter, a data acquisition and storage device, and an attitude monitoring device; The main controller is electrically connected to the magnetic field compensation modulation module, the transient electromagnetic transmitter, the data acquisition and storage device, and the attitude monitoring device, respectively; the superconducting magnetometer is connected to the magnetic field compensation modulation module and the data acquisition and storage device, respectively. The main controller is used to control the superconducting magnetometer to collect static geomagnetic field data of the current measuring point in real time. Based on the comparison result between the measured geomagnetic field value and the preset magnetic field compensation threshold, it generates a reverse compensation control command and sends it to the magnetic field compensation modulation module. The magnetic field compensation modulation module outputs a compensation signal to cancel the geomagnetic field of the measuring point so that the superconducting magnetometer remains in a locked state. The main controller is also used to control the transient electromagnetic transmitter to transmit an excitation signal when the superconducting magnetometer is in a locked state, and to control the data acquisition and storage device to continuously acquire the raw data of the transient electromagnetic magnetic field attenuation curve for each measurement cycle in a non-superimposed single raw data acquisition mode. The main controller is also used to identify the measurement point switching action based on the position data uploaded by the attitude monitoring device, and automatically update the geomagnetic field compensation parameters when the measurement point is switched, and control the magnetic field compensation modulation module to adapt to the geomagnetic field environment of the new measurement point so as to achieve continuous measurement.

[0008] A superconducting transient electromagnetic continuity measurement method, based on the system described above, comprises the following steps: S1 controls the superconducting magnetometer to collect static geomagnetic field data of the current measuring point in real time; S2, compare the measured geomagnetic field value with the preset magnetic field compensation threshold (generally set at around 50,000 nT), and perform geomagnetic field compensation according to the comparison result to keep the superconducting magnetometer in a locked state. S3. With the superconducting magnetometer locked, an excitation signal is transmitted according to a preset timing sequence. The fundamental frequency of transmission is generally less than 5Hz (corresponding to a time base of 50ms), the duty cycle is 50%, the side length of the transmission frame is selected from 200m to 1000m depending on the actual situation, and the transmission current is generally greater than 20A. At the same time, raw data of the transient electromagnetic field attenuation curve for each measurement cycle are continuously acquired in a non-superimposed single raw data acquisition mode, and the sampling rate is generally set to 1MHz. S4. During the data acquisition process, the locking status of the superconducting magnetometer and the amplitude of geomagnetic field fluctuations are monitored in real time. When a loss of lock or geomagnetic field fluctuations exceed a preset threshold are detected, abnormal data for the current period are removed. S5: Real-time acquisition of device position movement data; identification of measurement point switching actions based on the position movement data; automatic update of geomagnetic field compensation parameters when measurement point switching occurs; and return to execution steps S2 to S4 to achieve continuous measurement.

[0009] Preferably, before step S1, the method further includes: inputting preset measurement parameters and completing system initialization through a human-computer interaction terminal. The preset measurement parameters include field measurement profile path, sampling frequency, magnetic field compensation threshold, sensor lock-in state threshold, abnormal data discrimination threshold, and transient electromagnetic emission timing parameters.

[0010] Preferably, in step S2, the locking voltage of the superconducting magnetometer is monitored in real time as a locking state parameter, and when the locking voltage deviates from the preset range, the amplitude of the compensation signal is dynamically adjusted.

[0011] Preferably, in step S2, the locked state of the superconducting magnetometer is dynamically maintained by a closed-loop control method: the output signal of the superconducting magnetometer is collected in real time as a feedback quantity, the feedback quantity is compared with the locked target value, and the compensation signal is continuously adjusted according to the comparison result so that the working magnetic field of the superconducting magnetometer is always maintained within the locked range.

[0012] Preferably, in step S3, the non-overlay single raw data acquisition mode is as follows: each measurement cycle independently acquires complete raw data of the transient electromagnetic field decay curve and stores it directly, and the data from different measurement cycles are not overlaid and averaged.

[0013] Preferably, in step S4, only the raw measurement data collected when the superconducting magnetometer is in a stable locked state and the amplitude of the geomagnetic field fluctuation does not exceed the preset threshold is included in the valid dataset.

[0014] Preferably, in step S5, the latitude and longitude coordinates, heading angle, pitch angle and roll angle data of the device are collected in real time by the GPS positioning unit and the nine-axis attitude sensor, and the measurement point is determined to be switched based on the change of the latitude and longitude coordinates.

[0015] Preferably, after the measurement is completed, the collected effective transient electromagnetic attenuation data are batched, classified, and stored to generate a continuous measurement profile data file.

[0016] Preferably, in underwater or airborne transient electromagnetic exploration scenarios, depth or height data of the equipment is collected by a depth sensor or barometric altimeter, and the switching action of the measuring point in three-dimensional space is identified by combining the depth or height data with the planar position data.

[0017] Compared with the prior art, the present invention discloses the following technical effects: First, the present invention automatically collects static geomagnetic field data and generates reverse compensation control commands through the main controller, and dynamically cancels the geomagnetic field of the measuring point in conjunction with the magnetic field compensation modulation module. This replaces the traditional manual modulation and manual frequency locking operation, which can eliminate the shutdown and debugging steps after the measuring point switching, and realize continuous and uninterrupted measurement of the field profile. This is conducive to improving the efficiency of field measurement and shortening the exploration period.

[0018] Secondly, this invention addresses the characteristics of superconducting magnetometers, such as direct observation of magnetic fields, strong amplitude of late-stage data, and high native signal-to-noise ratio. It adopts a non-superimposed single-cycle raw data acquisition mode, which avoids the problem of attenuation curve distortion caused by mixing out-of-lock abnormal data with normal data in traditional superimposition strategies. This is beneficial for completely preserving the native high-precision late-stage data of superconducting magnetic field measurement and improving data authenticity.

[0019] Third, the present invention monitors the locking state parameters of the superconducting magnetometer in real time and dynamically fine-tunes the amplitude of the compensation signal through the main controller, forming a closed-loop control for geomagnetic field compensation. This can adapt to the complex and ever-changing geomagnetic field environment in real time, which is beneficial to maintaining the continuous locking state of the superconducting magnetometer and reducing the risk of frequent sensor loss of lock.

[0020] Fourth, this invention monitors the locking status and geomagnetic field fluctuations in real time during data acquisition, automatically marks and removes periodic data that is out of lock or whose fluctuations exceed the threshold, and retains only valid data under stable locking conditions. This can filter abnormal data from the source of data acquisition, which is beneficial to improving the consistency and reliability of measurement data.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the system structure of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the method flow of Embodiment 2 of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] Example 1 This embodiment provides a superconducting transient electromagnetic continuous measurement system for deep metal mineral geological exploration (detection depth 0-800m, complex geomagnetic field interference, etc.).

[0026] This example is applicable to deep mineral exploration in mountainous and hilly areas. The static geomagnetic field fluctuation range at the measuring point is ±50,000 nT, and there is interference from industrial 50Hz power frequency and terrain undulations. The equipment is required to be able to continuously measure for 8 hours without interruption, with attitude adaptive correction and real-time geomagnetic field compensation. The core technical specifications of the system are: magnetic field measurement noise ≤10fT / √Hz@1kHz, signal bandwidth 0–200kHz, transmission current 0-50A, dynamic range 125dB, detection depth up to 800m, positioning attitude accuracy 0.01°, and data sampling rate 1KHz.

[0027] The system consists of seven core units: main controller, superconducting magnetometer, magnetic field compensation modulation module, transient electromagnetic transmitter, data acquisition and storage device, attitude monitoring device, and human-machine interface terminal. The detailed configuration of each module is as follows: like Figure 1 As shown, the system includes a main controller, a superconducting magnetometer, a magnetic field compensation modulation module, a transient electromagnetic transmitter, a data acquisition and storage device, an attitude monitoring device, and a human-machine interaction terminal.

[0028] (a) Main controller 1. The module consists of a core main control unit, a high-precision clock synchronization module, a multi-channel IO control module, a serial communication module, a power supply regulation module, and a fault self-test module, providing timing synchronization, logic control, data processing, and instruction issuance functions for the entire system.

[0029] 2. The model adopts an industrial-grade embedded main control STM32H743 + FPGA XC7A35T dual-core architecture, and is equipped with a GPS / BeiDou dual-mode clock synchronization module to achieve microsecond-level timing synchronization of the entire device, eliminating the problem of timing misalignment in transmission, acquisition and compensation.

[0030] 3. The main controller connects to each sub-device via RS485, Ethernet, and a high-precision analog interface. Upon power-up, it automatically completes system-wide hardware self-test, parameter initialization, and clock calibration. During measurement, it acquires attitude, magnetic field, and emission current data in real time, performs geomagnetic field compensation algorithm calculations, transient electromagnetic data preprocessing, and fault diagnosis, providing fully automatic closed-loop control without manual intervention. It supports adaptive parameter adjustment, automatically adjusting compensation output parameters based on on-site geomagnetic field fluctuations.

[0031] (II) Superconducting magnetometer 1. The module consists of a high-temperature superconducting SQUID sensing probe, a high-temperature cooling module, a signal preamplifier module, an impedance matching module, and a shielded protective shell. It is the core of the system for high-precision magnetic field signal acquisition, replacing traditional induction coil sensors and has the advantages of low noise, wide bandwidth, and high slew rate.

[0032] 2. The model can be the high-temperature superconducting SQUID magnetometer developed by the Institute of Geophysical and Geochemical Exploration, Chinese Academy of Geological Sciences. Its core parameters are: magnetic field noise 10fT / √Hz@1kHz, slew rate 5mT / s, system bandwidth 200kHz. It is fully adapted to the requirements of weak secondary field signal acquisition in deep exploration and its resistance to environmental magnetic field interference is far superior to that of traditional coil sensors.

[0033] 3. The equipment is equipped with a closed-loop low-temperature constant temperature refrigeration system to maintain the superconducting probe in a low-temperature working state throughout the process, ensuring the stability of the superconducting lock-in range; the input end is connected to the magnetic field compensation modulation module to receive compensation electrical signals to cancel the static geomagnetic field and stabilize the working magnetic field within the ±1000nT lock-in range; the output end is connected to the data acquisition and storage device through a low-noise shielded cable to output the original signals of the static geomagnetic field and transient electromagnetic attenuation secondary field in real time, without signal distortion or bandwidth limitation.

[0034] (iii) The magnetic field compensation modulation module is controlled by the main controller and is used to receive the reverse compensation control command issued by the main controller, output the compensation electrical signal to the superconducting magnetometer, cancel the geomagnetic field at the measuring point, and maintain the working magnetic field of the superconducting magnetometer within the locking range.

[0035] 1. The module consists of a DSP modulation and control unit, a high-precision DA conversion module, a power amplifier output module, a compensation coil drive unit, a feedback sampling module, and a signal filtering module, enabling real-time monitoring and dynamic reverse compensation of the geomagnetic field.

[0036] 2. The model can be selected as a high-precision magnetic field dynamic compensation module, equipped with a three-component rectangular compensation coil, with a compensation accuracy of ±1nT and a response speed of 1μs, which can follow the dynamic fluctuations of the geomagnetic field in real time.

[0037] 3. The module is controlled by the main controller throughout the process and receives real-time reverse compensation control commands issued by the main controller; it collects the deviation of the working magnetic field of the superconducting magnetometer in real time through the feedback sampling module, forms a closed-loop adjustment, and dynamically outputs a reverse compensation electrical signal to drive the compensation coil, accurately canceling the static geomagnetic field, slow magnetic field drift and environmental stray magnetic field at the measurement point; it always keeps the working magnetic field of the superconducting magnetometer within the superconducting lock-in threshold range, avoids magnetometer lock-in and signal saturation, and ensures the stability of continuous measurement.

[0038] (iv) The transient electromagnetic transmitter is controlled by the main controller and is used to transmit excitation electromagnetic fields according to a preset timing sequence to stimulate the underground medium to generate transient electromagnetic response signals.

[0039] 1. The module consists of a voltage regulator power supply unit, a timing control unit, an inverter transmitter unit, a current detection feedback unit, a damping protection module, and a transmitter coil interface unit, which are used to output a stable and controllable excitation electromagnetic field.

[0040] 2. The model uses the CRONE PEM professional transient electromagnetic transmitter, which is suitable for deep ground exploration scenarios. It has a maximum transmission current of 50A, a transmission voltage of 120V, a turn-off time of 500μs, supports multiple time sequences and multiple frequency preset transmission modes, and is equipped with a 400m×900m rectangular transmission frame to meet the excitation requirements of 800m depth exploration.

[0041] 3. It operates strictly according to the exploration sequence preset by the main controller, supporting both single pulse and continuous pulse cyclic transmission modes; after power-on, it automatically calibrates the transmission current and timing parameters, and provides real-time feedback on the transmission status to the main control system; the primary field excitation of the underground rock strata and mineral layers generates an induced secondary transient electromagnetic field, providing an effective excitation source for magnetometer signal acquisition; the built-in damping protection module can suppress voltage spikes at the moment of transmission shutdown, avoiding equipment damage and signal interference.

[0042] (v) The data acquisition and storage device is used to acquire, cache and store the raw transient electromagnetic attenuation data output by the superconducting magnetometer in real time under the control of the main controller, and upload it to the main controller synchronously.

[0043] 1. The module includes a high-speed AD acquisition unit, a data cache module, a solid-state storage unit, a data transmission module, a signal noise reduction module, and a timing alignment module.

[0044] 2. The model adopts the CDR2 high-precision multi-channel data acquisition recorder with a maximum sampling rate of 1MHz, 24-bit AD conversion accuracy, dynamic range of 140dB, built-in 1TB industrial-grade solid-state drive, and supports real-time data caching, local storage and synchronous upload.

[0045] 3. Under the timing control of the main controller, the system synchronously acquires raw data of transient electromagnetic attenuation, magnetic field compensation parameters, and transmitter operating parameters output by the superconducting magnetometer; filters out 50Hz power frequency interference and high-frequency noise interference through the built-in noise reduction module; achieves real-time data caching and local persistent storage, and simultaneously uploads the data to the main controller via Ethernet for preprocessing; supports breakpoint resume, automatically resumes data acquisition after power failure and restart in the field, and ensures no data loss.

[0046] (vi) Attitude monitoring equipment is used to collect the attitude and position movement data of the equipment in real time and upload it synchronously to the main controller. The module consists of a high-precision gyroscope, tilt sensor, GPS / BeiDou positioning module, data synchronization transmission module, and attitude calculation unit. The model can be JY-901 high-precision attitude sensor, with an attitude measurement accuracy of 0.01°, a positioning accuracy of ±0.5m, and a data update frequency of 100Hz, suitable for field movement and terrain undulation measurement scenarios. Throughout the measurement process, the elevation angle, roll angle, azimuth angle of the superconducting magnetometer and transmitting coil, as well as the GPS position coordinates and displacement data of the measuring point are collected in real time; the data is uploaded to the main controller in real time. The main control system completes magnetic field signal attitude correction and position matching based on the attitude data, eliminating measurement errors caused by terrain undulation and slight equipment offset, and ensuring the consistency and accuracy of data in continuous movement measurement.

[0047] (vii) The human-machine interface terminal is used for parameter initialization settings, measurement status display, and abnormal alarms. Initial configuration is only required before measurement starts, and no manual intervention is needed throughout the measurement process. The module consists of an industrial touchscreen display, parameter configuration module, status display module, audible and visual alarm module, and data query module. A 7-inch industrial-grade touchscreen all-in-one machine is available as an option, with wide operating temperature (-20℃~+50℃), dustproof and waterproof, suitable for harsh outdoor environments. Manual initialization configuration is only required before the measurement operation starts, including core parameters such as exploration depth, transmission sequence, compensation threshold, sampling frequency, and alarm threshold. The system's operating status, magnetic field data, equipment attitude, and remaining storage capacity are displayed in real time throughout the measurement process. Audible and visual alarms are automatically triggered for hardware failures, magnetic field loss of lock, signal abnormalities, and power supply abnormalities. No manual operation is required during the measurement process, achieving fully automated continuous measurement.

[0048] Example 2 This embodiment provides a superconducting transient electromagnetic continuous measurement method, implemented using the superconducting transient electromagnetic continuous measurement system described in Embodiment 1. It is suitable for continuous exploration scenarios of deep metallic mineral profiles in mountainous areas, targeting gold-bearing polymetallic veins at depths of 0–1500m. Addressing the pain points of frequent geomagnetic field fluctuations, large terrain undulations, slight equipment misalignment, frequent downtime for debugging in traditional measurements, data superposition distortion, and difficulty in identifying abnormal data, this method achieves unattended, seamless, continuous, and high-precision raw data acquisition. The process is as follows: Figure 2 As shown, the specific steps and corresponding actual measurement details are as follows: This field exploration project pre-planned a north-south oriented measurement profile with a total length of 2000m, with measuring points spaced 10m apart, totaling 200 continuous measuring points. The exploration equipment moved at a speed of 0.5m / s, with no downtime or manual adjustments required throughout the entire process, achieving full coverage continuous measurement of the profile. The specific implementation steps are as follows: S1: Real-time acquisition of raw static geomagnetic field data at the measuring point In the initial stage of the measurement, system parameters were initialized via a human-computer interaction terminal. The preset superconducting magnetometer locking range was ±1000nT, the geomagnetic field compensation threshold was ±5000nT, the measurement period was 100ms, and the sampling rate was 1MHz. After the device completed its power-on self-test, the main controller drove the superconducting magnetometer to start the global geomagnetic field acquisition in real time.

[0049] For complex electromagnetic environments in mountainous areas, the superconducting magnetometer collects real-time raw data of the three-component static geomagnetic field at the current measurement point with a sampling rate of 1MHz. In a single measurement cycle, it can output 10,000 sets of raw magnetic field sampling points, fully recording the real-time geomagnetic field amplitude and fluctuation trend at the measurement point. It accurately captures small magnetic field distortion and drift data in the field, providing full raw data support for subsequent dynamic compensation and precise positioning, and completely avoiding the shortcomings of traditional equipment's single-point fixed value compensation that cannot adapt to dynamic fluctuations of the magnetic field.

[0050] The core function of this step is to acquire real-time geomagnetic field environment parameters at each measuring point, establish a database of the magnetic field environment at each measuring point, and provide a precise input basis for the closed-loop dynamic compensation algorithm.

[0051] S2: Dynamic Comparison of Geomagnetic Magnetic Field and Adaptive Locking of Superconducting Magnetometer The main controller reads the measured geomagnetic field values ​​collected by S1 in real time and performs high-speed differential comparison calculations with the preset ±5000nT magnetic field compensation threshold. The measured static geomagnetic field value at the initial measurement point in this experiment was 48200nT, which far exceeds the stable locking range of the superconducting magnetometer. The main controller quickly calculates and generates corresponding amplitude and phase reverse compensation control commands, which are then sent to the magnetic field compensation modulation module.

[0052] After receiving the command, the magnetic field compensation modulation module outputs a high-precision compensation electrical signal with a response speed of 1μs, driving the three-component compensation coil to generate a reverse compensation magnetic field, accurately canceling the original geomagnetic field at the measurement point. During the compensation process, the main controller continuously monitors the lock-up status parameters of the superconducting magnetometer in real time, dynamically judging the residual magnetic field deviation: when the residual magnetic field deviation is less than 50nT, the current compensation parameters are maintained; when a momentary magnetic field drift occurs in the field environment and the residual deviation exceeds 50nT, the amplitude and phase of the compensation signal are finely adjusted in real time to achieve closed-loop dynamic adjustment.

[0053] After dynamic compensation, the working magnetic field of the superconducting magnetometer at all measuring points was stably maintained within the preset locking range of ±1000 nT, without any loss of lock or signal saturation issues. This measurement process completely replaces the traditional manual parameter adjustment and sensor locking operation mode, realizing fully automated geomagnetic field detection, dynamic compensation, and stable sensor locking, and is suitable for complex and dynamically changing magnetic field scenarios in the field.

[0054] S3: Single-cycle raw data non-overlapping continuous acquisition of transient electromagnetic signals Once the superconducting magnetometer is locked in a stable state and the magnetic field fluctuations are completely within the preset allowable range, the main controller initiates the transient electromagnetic excitation and data acquisition process. The measured preset transmission sequence is: transmission pulse width 100ms, off-time 1000μs, and transmission current 50A, suitable for exploration requirements of mineral veins at a depth of 1500m. The main controller controls the CRONE PEM transient electromagnetic transmitter to continuously transmit a field excitation signal once according to a fixed sequence, stimulating the underground rock strata and mineral veins to generate a secondary transient electromagnetic response attenuation field.

[0055] The CDR2 data acquisition and storage device is synchronously triggered to start high-speed sampling. It adopts a non-overlay single raw data acquisition mode, and independently acquires a complete set of raw data of transient electromagnetic field decay curves for each 100ms measurement cycle. No multi-cycle overlay or multi-point averaging noise reduction processing is performed throughout the process.

[0056] Combining the low noise, high sensitivity, and high fidelity of late-stage signals of the superconducting magnetometer in this system, the native signal-to-noise ratio of the acquired deep weak secondary fields is far higher than that of traditional coil sensors, ensuring data validity without the need for noise reduction by superposition. In actual measurements, the traditional blind superposition strategy is completely abandoned, perfectly preserving early shallow details and late-stage weak anomalous signals in the decay curve. This thoroughly solves the industry pain points of traditional superposition noise reduction, such as the average masking of vein anomalous signals, curve distortion, and low accuracy in deep identification, thus fully preserving the true electromagnetic response characteristics of underground geological bodies.

[0057] S4: Real-time identification, marking, and automatic removal of abnormal data During the continuous data acquisition process, the main controller synchronously establishes a multi-parameter real-time monitoring mechanism, and high-frequency acquires core parameters such as the superconducting magnetometer's lock-in status, geomagnetic field fluctuation amplitude, equipment operating voltage, and signal jump amplitude to determine the validity of the data in real time.

[0058] During the actual measurement of 200 measurement points, three types of abnormal operating conditions were identified and automatically eliminated: First, two measurement points experienced instantaneous electromagnetic interference from thunderstorms, causing the amplitude of geomagnetic field fluctuations to momentarily exceed the ±300nT threshold, resulting in a brief loss of sensor lock-on tendency; second, three measurement points experienced strong power frequency interference from surrounding construction, causing sudden signal jumps; and third, one measurement point experienced brief equipment vibration and displacement, resulting in abnormal operating parameters. For these abnormal operating conditions, the system marked the corresponding measurement period data as invalid data in real time, automatically eliminating it from the valid dataset, without requiring equipment shutdown or retesting.

[0059] Only raw data collected when the superconducting magnetometer is continuously and stably locked, the geomagnetic field fluctuations are within the preset threshold, the signal has no abnormal jumps, and the equipment operating parameters are normal can be entered into the valid dataset. This ensures strict control over data accuracy from the source of data acquisition and avoids abnormal data from contaminating the overall profile data.

[0060] S5: Automatic measurement point switching and seamless continuous measurement During the actual test, the JY-901 attitude monitoring device collected GPS position, pitch angle, roll angle, and displacement attitude data in real time at a frequency of 100Hz and uploaded them synchronously to the main controller. The main controller analyzed the position data in real time to determine the device's movement status and measurement point switching nodes.

[0061] When the device is detected to have moved at a constant speed of 10m and arrived at the next preset measurement point, the system does not need to stop, manually calibrate or debug, or restart the device. The main controller automatically triggers the measurement point switching and adaptation process: reads the initial geomagnetic field data of the new measurement point in real time, quickly updates the magnetic field compensation parameters, adapts to the differences in the magnetic field environment of the new measurement point, automatically completes the secondary locking calibration, and then continues to execute the compensation, locking, and acquisition process of S2–S4 to achieve seamless connection measurement between measurement points.

[0062] This 2000m profile was continuously measured at 200 points with a measurement point switching time of ≤2s and no measurement gaps. This completely solves the problem of low work efficiency caused by the need to stop the machine to adjust parameters and restart calibration after the completion of a single point in traditional transient electromagnetic measurement.

[0063] Expanding Real-World Measurement Scenarios (Aerial / Underwater Exploration): When switching to deep-water mineral exploration, the attitude monitoring equipment integrates a high-precision depth sensor to collect underwater depth data from the probe in real time; when switching to aerial remote sensing exploration, it integrates a barometric altimeter to collect flight altitude data. The main controller combines planar GPS position data with 3D depth / altitude spatial data to accurately identify the switching positions of 3D measurement points, enabling seamless and continuous measurement across all dimensions in underwater and aerial scenarios.

[0064] S6: Batch Data Processing and Profile File Generation After the completion of the full profile measurement at 200 measurement points, the main controller automatically terminated the transmission and acquisition process, and batch-processed, categorized, and archived all valid raw data. The system performs multi-dimensional classification and storage according to measurement point number, measurement sequence, position coordinates, attitude correction parameters, and magnetic field compensation parameters, automatically removes invalid data fragments, and generates a complete 2000m continuous measurement profile raw data file.

[0065] The generated profile data curves are complete and detailed, without superposition distortion or missing breaks. No manual secondary noise reduction, superposition, or correction is required. They can be directly imported into geological inversion software to conduct analysis of the burial depth, thickness, and resistivity characteristics of deep veins, accurately identify polymetallic vein anomalies at depths of 0–1500m, and fully meet the engineering application needs of fine exploration of deep mineral resources.

[0066] Through field verification of continuous mountain profile exploration, this measurement method, based on the hardware system of Example 1, achieves fully automated, downtime-free, distortion-free, and high-fidelity superconducting transient electromagnetic continuous measurement. Compared with traditional measurement methods, it eliminates the need for manual parameter adjustment, secondary data processing, and downtime calibration at measurement points, effectively avoiding the problems of human operation errors and data superposition distortion. This significantly improves the operational efficiency and deep detection accuracy of field profile exploration, and is adaptable to exploration operations in multiple scenarios including land, underwater, and aerial exploration, making it highly practical for engineering applications.

[0067] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Those skilled in the art can flexibly select other technical features according to actual needs. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should fall within the protection scope of the claims of the present invention. To avoid obscuring the core technical solutions of the present invention, well-known construction processes, operating conditions, etc., are not described in detail in this document.

Claims

1. A superconducting transient electromagnetic continuous measurement system, characterized in that, It includes a main controller, a superconducting magnetometer, a magnetic field compensation modulation module, a transient electromagnetic transmitter, data acquisition and storage equipment, and attitude monitoring equipment; The main controller is electrically connected to the magnetic field compensation modulation module, the transient electromagnetic transmitter, the data acquisition and storage device, and the attitude monitoring device, respectively; the superconducting magnetometer is connected to the magnetic field compensation modulation module and the data acquisition and storage device, respectively. The main controller is used to control the superconducting magnetometer to collect static geomagnetic field data of the current measuring point in real time. Based on the comparison result between the measured geomagnetic field value and the preset magnetic field compensation threshold, it generates a reverse compensation control command and sends it to the magnetic field compensation modulation module. The magnetic field compensation modulation module outputs a compensation signal to cancel the geomagnetic field of the measuring point so that the superconducting magnetometer remains in a locked state. The main controller is also used to control the transient electromagnetic transmitter to transmit an excitation signal when the superconducting magnetometer is in a locked state, and to control the data acquisition and storage device to continuously acquire the raw data of the transient electromagnetic magnetic field attenuation curve for each measurement cycle in a non-superimposed single raw data acquisition mode. The main controller is also used to identify the measurement point switching action based on the position data uploaded by the attitude monitoring device, and automatically update the geomagnetic field compensation parameters when the measurement point is switched, and control the magnetic field compensation modulation module to adapt to the geomagnetic field environment of the new measurement point so as to achieve continuous measurement.

2. A superconducting transient electromagnetic continuous measurement method, based on the system described in claim 1, characterized in that, Includes the following steps: S1 controls the superconducting magnetometer to collect static geomagnetic field data of the current measuring point in real time; S2, compare the measured geomagnetic field value with the preset magnetic field compensation threshold, and perform geomagnetic field compensation according to the comparison result to keep the superconducting magnetometer locked. S3, when the superconducting magnetometer is in the locked state, the excitation signal is emitted according to the preset timing sequence, and the raw data of the transient electromagnetic field attenuation curve of each measurement cycle is continuously acquired in the non-superimposed single raw data acquisition mode. S4. During the data acquisition process, the locking status of the superconducting magnetometer and the amplitude of geomagnetic field fluctuations are monitored in real time. When a loss of lock or geomagnetic field fluctuations exceed a preset threshold are detected, abnormal data for the current period are removed. S5: Real-time acquisition of device position movement data; identification of measurement point switching actions based on the position movement data; automatic update of geomagnetic field compensation parameters when measurement point switching occurs; and return to execution steps S2 to S4 to achieve continuous measurement.

3. The superconducting transient electromagnetic continuous measurement method according to claim 2, characterized in that: Before step S1, the method further includes: inputting preset measurement parameters and completing system initialization through a human-computer interaction terminal. The preset measurement parameters include field measurement profile path, sampling frequency, magnetic field compensation threshold, sensor lock-in state threshold, abnormal data discrimination threshold, and transient electromagnetic emission timing parameters.

4. The superconducting transient electromagnetic continuous measurement method according to claim 2, characterized in that: In step S2, the locking voltage of the superconducting magnetometer is monitored in real time as a locking state parameter. When the locking voltage deviates from the preset range, the amplitude of the compensation signal is dynamically fine-tuned.

5. The superconducting transient electromagnetic continuous measurement method according to claim 2, characterized in that: In step S2, the locked state of the superconducting magnetometer is dynamically maintained through closed-loop control: the output signal of the superconducting magnetometer is collected in real time as a feedback quantity, the feedback quantity is compared with the locked target value, and the compensation signal is continuously adjusted according to the comparison result so that the working magnetic field of the superconducting magnetometer is always maintained within the locked range.

6. The superconducting transient electromagnetic continuous measurement method according to claim 2, characterized in that: In step S3, the non-superimposed single raw data acquisition mode is as follows: each measurement cycle independently acquires complete raw data of the transient electromagnetic field decay curve and stores it directly, and the data from different measurement cycles are not superimposed and averaged.

7. The superconducting transient electromagnetic continuous measurement method according to claim 2, characterized in that: In step S4, only the raw measurement data collected when the superconducting magnetometer is in a stable locked state and the amplitude of geomagnetic field fluctuations does not exceed the preset threshold are included in the valid dataset.

8. The superconducting transient electromagnetic continuous measurement method according to claim 2, characterized in that: In step S5, the latitude and longitude coordinates, heading angle, pitch angle and roll angle data of the device are collected in real time by the GPS positioning unit and the nine-axis attitude sensor. The change of the latitude and longitude coordinates determines whether the measuring point has been switched.

9. The superconducting transient electromagnetic continuous measurement method according to claim 2, characterized in that: After the measurement is completed, the collected effective transient electromagnetic attenuation data are batched, classified and stored to generate continuous measurement profile data files.

10. The superconducting transient electromagnetic continuous measurement method according to claim 2, characterized in that: In underwater or airborne transient electromagnetic exploration scenarios, depth or height data of the equipment is collected by depth sensors or barometric altimeters, and the switching action of measurement points in three-dimensional space is identified by combining the depth or height data with planar position data.

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