High-reliability long-endurance seabed-based self-contained electromagnetic observation device

Abstract

The application discloses a high-reliability long-endurance seabed base self-contained electromagnetic observation device, and belongs to the technical field of seabed detection. The device comprises a structural member and an electronic component. The structural member comprises a floating body, a measuring arm, a counterweight and a release mechanism. The electronic component comprises an electronic cabin, a battery cabin, an electrode and a magnetic sensor. The measuring arm is connected with the floating body. The electronic cabin, the battery cabin and the magnetic sensor are embedded in the interior of the measuring arm, and the electrode is installed at the end of the measuring arm away from the floating body. The battery cabin, the electrode and the magnetic sensor are electrically connected with the electronic cabin. The device takes the component, i.e. the structure, as a design concept, directly embeds the magnetic sensor, the electronic cabin and the battery cabin in the interior of the measuring arm, does not need to separately install the components on different positions of the instrument frame through independent supports, and does not need to additionally set a support arm for the magnetic sensor. The measuring arm serves as both a bearing structure of the electrode and a containing shell of the electronic cabin, the battery cabin and the magnetic sensor, and realizes deep fusion of the functional components and the bearing structure.

Description

Technical Field

[0001] This invention relates to the field of seabed exploration technology, and in particular to a highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device. Background Technology

[0002] Seafloor electromagnetic detection is an important and effective means of exploring deep-sea structures, possessing advantages such as large detection depth and high sensitivity to high-conductivity anomalies. It has been widely applied in the study of marine geological structures such as mid-ocean ridges, subduction zones, and submarine volcanoes, as well as in the exploration of seafloor natural gas hydrates and oil and gas resources. Current seafloor electromagnetic observations mainly rely on seabed-based self-contained electromagnetic receivers. These instruments are deployed to the seabed and autonomously collect electromagnetic field signals. After the collection cycle, a counterweight is released via an acoustic release mechanism, allowing the receiver to float to the surface for buoyancy and recovery. Over the years, seafloor electromagnetic receivers have made significant progress in miniaturization, low power consumption, and high-precision time synchronization. However, current research on seabed-based self-contained electromagnetic observation devices still faces the following technical limitations:

[0003] First, the seabed environment is complex and variable. Instruments in deep water face immense environmental pressures, compounded by adverse factors such as bottom currents and silt adsorption. Affected by bottom current impacts and unstable seabed sediment, the receiver may shift or tilt on the seabed. Existing seabed electromagnetic receivers typically concentrate heavier components such as the electronics compartment and battery compartment in the upper or middle part of the frame, resulting in a high center of gravity. Under the continuous scouring of bottom currents, this makes the receiver prone to attitude instability or even tipping, severely impacting the coupling between the sensor and the seabed and the reliability of long-term observations. Although some solutions attempt to control the center of gravity through a vertically combined dual-compartment sphere structure, this is essentially a stacked compartment design, with limited downward displacement of the center of gravity, and it does not fundamentally solve the hydrodynamic stability problem.

[0004] Secondly, existing seabed electromagnetic receivers generally adopt a "frame + cabin" assembly model, with core components such as the electronic cabin, battery cabin, and magnetic sensor installed in different positions on the instrument frame, each occupying independent installation space. The electric field measurement arm is usually a fixed-length structure, large in size and inconvenient to store. This distributed layout results in a large overall size, high structural redundancy, and low space utilization. Although some solutions have adopted telescopic or foldable electrode arm designs to facilitate offshore operations, foldable arms only solve the storage problem and do not achieve structural integration of the core components and the measurement arm. Slow ascent speed leads to long shipboard time and low offshore operational efficiency.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device.

[0007] To achieve the above objectives, the present invention provides a highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device, comprising: structural components and electronic components; the structural components include: a float, a measuring arm, a counterweight, and a release mechanism; the electronic components include: an electronics compartment, a battery compartment, electrodes, and a magnetic sensor; the measuring arm is connected to the float; the release mechanism is connected to the counterweight; the electronics compartment, the battery compartment, and the magnetic sensor are embedded inside the measuring arm, and the electrodes are installed at the end of the measuring arm away from the float; the battery compartment, the electrodes, and the magnetic sensor are all electrically connected to the electronics compartment.

[0008] In one embodiment of the present invention, it further includes: a center of gravity adaptive adjustment mechanism; the center of gravity adaptive adjustment mechanism is disposed inside the measuring arm; the center of gravity adaptive adjustment mechanism includes a guide rail and a drive assembly; the electronic compartment, the battery compartment and / or the magnetic sensor are mounted on the guide rail, and the drive assembly is used to drive the electronic compartment, the battery compartment and / or the magnetic sensor to move along the length direction of the measuring arm.

[0009] In one embodiment of the present invention, the center of gravity adaptive adjustment mechanism has a bottom-sitting observation mode and an ascent and recovery mode; in the bottom-sitting observation mode, the electronic compartment, the battery compartment and / or the magnetic sensor are located at the end of the measuring arm away from the float; in the ascent and recovery mode, the electronic compartment, the battery compartment and / or the magnetic sensor move to the end closer to the float.

[0010] In one embodiment of the present invention, the measuring arm is connected to the float via a hinge, and the measuring arm has an extended state and a folded state that rotate relative to the float; the measuring arm is in the extended state when bottoming out for observation, and in the folded state when surfacing for recovery; in the folded state, a plurality of the measuring arms are retracted and attached to the side of the float.

[0011] In one embodiment of the present invention, the release mechanism is connected to the counterweight, and after the counterweight is released, the measuring arm automatically switches from the unfolded state to the folded state under the action of buoyancy.

[0012] In one embodiment of the present invention, the battery compartment is a modular and expandable battery compartment that is detachably installed inside the measuring arm.

[0013] In one embodiment of the present invention, the magnetic sensor is an inductive magnetic sensor; the inductive magnetic sensor includes: a first inductive magnetic sensor and a second inductive magnetic sensor; the first inductive magnetic sensor and the second inductive magnetic sensor are disposed on different measuring arms.

[0014] In one embodiment of the present invention, the magnetic sensor is a fluxgate sensor.

[0015] In one embodiment of the present invention, the number of battery compartments is at least two, and they are arranged on different measuring arms.

[0016] In one embodiment of the present invention, there are four measuring arms, which are arranged in a cross shape, with an included angle of 90° between adjacent measuring arms.

[0017] Compared with the prior art, the highly reliable, long-endurance, seabed-based self-contained electromagnetic observation device according to the present invention has the following advantages:

[0018] First, this invention embeds the heaviest components, such as the electronics compartment and battery compartment, into the measuring arm located at the bottom of the instrument, instead of mounting them in the middle or upper part of the frame as in existing technologies. This significantly lowers the instrument's center of gravity. Simultaneously, the measuring arm is directly connected to the float, and the electronics compartment, battery compartment, and magnetic sensor are integrated within the measuring arm, resulting in a more compact structure. Once the instrument is firmly on the seabed, the low center of gravity significantly reduces the overturning moment caused by bottom current scouring, effectively suppressing changes in the instrument's attitude and preventing damage to the sensor-seabed coupling due to tilting or tipping. This significantly improves the reliability and data quality of long-term observations. In contrast, existing technologies, with heavy components mounted on the upper part of the frame, result in a higher center of gravity. This invention solves the problem of resisting bottom current disturbances at its structural source, achieving stable seabed observations without relying on additional counterweights.

[0019] Secondly, this invention adopts a component-as-structure design concept, directly embedding the magnetic sensor, electronics compartment, and battery compartment inside the measuring arm. Unlike existing technologies, this eliminates the need for dispersing components across different positions on the instrument frame using independent supports, and also avoids the need for an additional support arm for the magnetic sensor. The measuring arm serves as both the electrode support structure and the housing for the electronics compartment, battery compartment, and magnetic sensor, achieving deep integration of functional components and the support structure. This design eliminates redundant space between functional components and the support structure in traditional instruments, significantly improving the overall space utilization and structural compactness, facilitating deployment and recovery at sea. In existing technologies, the magnetic sensor needs to be mounted on the periphery of the frame via an additional support arm, the measuring arm has a single function of supporting the electrode, and each component occupies independent space, resulting in a large volume. This invention effectively solves these problems through an integrated design. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a highly reliable, long-endurance seabed-based self-contained electromagnetic observation device during seabed observation according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of a highly reliable, long-endurance seabed-based self-contained electromagnetic observation device when it rises to the surface, according to an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the structure of a first type of highly reliable, long-endurance, seabed-based self-contained electromagnetic observation device according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the circuit module of a first type of highly reliable, long-endurance, seabed-based self-contained electromagnetic observation device according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of a second type of highly reliable, long-endurance, seabed-based self-contained electromagnetic observation device according to an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of the circuit module of a second type of highly reliable, long-endurance seabed-based self-contained electromagnetic observation device according to an embodiment of the present invention. Detailed Implementation

[0026] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0027] Unless otherwise expressly stated, throughout this specification, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0028] like Figure 1 As shown, a highly reliable, long-endurance seabed-based self-contained electromagnetic observation device 100 according to a preferred embodiment of the present invention includes: structural components and electronic components.

[0029] The structural components include: float 10 and measuring arm 20. These components provide buoyancy, load-bearing capacity, connection, and release functions, forming the mechanical framework of the device.

[0030] The float 10 is a structural component that provides buoyancy to the entire unit. It can be made of low-density, high-pressure-resistant materials, such as foam float materials (e.g., composite foam plastics), hollow ceramic spheres, or pressure-resistant glass spheres. The float 10 is located at the top of the unit and provides sufficient net buoyancy during the recovery phase, allowing the device to rise to the surface after the counterweight is released. The size and buoyancy value of the float 10 can be designed to match the total weight of the unit and the water depth to ensure that the ascent speed meets operational requirements.

[0031] The electronic components include: an electronics compartment 30, a battery compartment 40, electrodes 50, and a magnetic sensor 60. These electronic components are used to sense, acquire, process, and store electromagnetic signals, and are the core of the device's functionality.

[0032] The measuring arm 20 is connected to the float 10. The electronics compartment 30, battery compartment 40, and magnetic sensor 60 are embedded inside the measuring arm 20, and the electrode 50 is installed at the end of the measuring arm 20 away from the float 10; the battery compartment 40, electrode 50, and magnetic sensor 60 are all electrically connected to the electronics compartment 30.

[0033] Among them, the electronic cabin 30 is a sealed cabin that integrates data acquisition and control system circuits. It contains electronic components such as a main control circuit board, an analog-to-digital converter, a highly stable clock, and a large-capacity storage module.

[0034] The battery compartment 40 provides power to the electronics compartment 30, the magnetic sensor 60, and the electrode 50.

[0035] The magnetic sensor 60 is an electronic component used to detect magnetic field signals on the seabed.

[0036] Electrode 50 is a sensing element used to detect the electric field signal on the seabed, and is usually one or more pairs of metal electrodes (such as non-polarized electrodes). Electrode 50 is inserted into seabed sediment or seawater, senses the potential difference between two points, and converts the electric field signal into an electrical signal, which is then transmitted to the electronics compartment 30.

[0037] It should be noted that the present invention directly embeds the electronic compartment 30, battery compartment 40 and magnetic sensor 60 into the measuring arm 20, so that the functional components that were originally scattered in various parts of the frame are concentrated in the measuring arm 20. By directly connecting the measuring arm 20 to the float 10, the traditional instrument frame as an intermediate load-bearing structure is eliminated.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] First, this invention embeds the heaviest components, such as the electronics compartment 30 and battery compartment 40, into the measuring arm 20 located at the bottom of the instrument, instead of mounting them in the middle or upper part of the frame as in existing technologies. This significantly lowers the center of gravity of the instrument. Simultaneously, the measuring arm 20 is directly connected to the float 10, and the electronics compartment 30, battery compartment 40, and magnetic sensor 60 are integrated within the measuring arm 20, resulting in a more compact structure. After the instrument settles on the seabed, the low center of gravity significantly reduces the overturning moment caused by bottom current scouring, effectively suppressing changes in the instrument's attitude on the seabed and preventing damage to the sensor-seabed coupling due to tilting or tipping. This significantly improves the reliability and data quality of long-term observations. In contrast, existing technologies, where heavy components are mounted on the upper part of the frame, result in a higher center of gravity. This invention solves the problem of resisting bottom current disturbances at the structural root, achieving stable seabed observations without relying on additional counterweights.

[0040] Secondly, this invention adopts a component-as-structure design concept, directly embedding the magnetic sensor 60, electronics compartment 30, and battery compartment 40 inside the measuring arm 20. Unlike existing technologies, this eliminates the need to separately mount components at different locations on the instrument frame using independent supports, and also avoids the need for an additional support arm for the magnetic sensor 60. The measuring arm 20 serves both as the load-bearing structure for the electrode 50 and as the housing for the electronics compartment 30, battery compartment 40, and magnetic sensor 60, achieving deep integration of functional components and the load-bearing structure. This design eliminates redundant space between functional components and the load-bearing structure in traditional instruments, significantly improving the overall space utilization and structural compactness, facilitating deployment and recovery at sea, and greatly increasing the instrument's ascent speed. In existing technologies, the magnetic sensor needs to be mounted on the periphery of the frame using an additional support arm, the measuring arm has a single function of supporting the electrode, and each component occupies independent space, resulting in a large volume. This invention effectively solves these problems through an integrated design.

[0041] In one embodiment of the present invention, a center of gravity adaptive adjustment mechanism is also included.

[0042] The center of gravity adaptive adjustment mechanism is located inside the measuring arm 20; the center of gravity adaptive adjustment mechanism includes a guide rail and a drive assembly; the electronic compartment 30, the battery compartment 40 and / or the magnetic sensor 60 are mounted on the guide rail, and the drive assembly is used to drive the electronic compartment 30, the battery compartment 40 and / or the magnetic sensor 60 to move along the length direction of the measuring arm 20.

[0043] The adaptive center of gravity adjustment mechanism is a mechanical device used to dynamically adjust the position of the center of gravity of the whole machine. Its core function is to actively change the internal mass distribution of the whole machine according to different working states of the device (bottoming out for observation or floating up for recovery), so as to change the position of the center of gravity to adapt to the requirements of different working conditions for the center of gravity position.

[0044] The guide rail is the component that provides guidance for linear motion and can take the form of a linear guide rail, slide rail, or guide rod. The drive assembly is the component that provides power and can be a lead screw mechanism driven by a micro stepper motor, a linear motor, or a hydraulic or pneumatic drive. The guide rail and drive assembly together constitute the motion actuator.

[0045] The electronics compartment 30, battery compartment 40, and / or magnetic sensor 60 are mounted on a guide rail and slide along it as movable mass blocks. The guide rail extends in the same direction as the length of the measuring arm 20, allowing these components to move along the length of the measuring arm 20. The battery compartment 40 and electronics compartment 30 account for 50% to 60% of the total weight of the device and are the main components contributing to center of gravity adjustment.

[0046] As can be seen, by setting a center-of-gravity adaptive adjustment mechanism consisting of guide rails and drive components inside the measuring arm 20, the electronic compartment 30, battery compartment 40, and / or magnetic sensor 60 are mounted on the guide rails and driven to move along the length of the measuring arm, thus achieving active and controllable adjustment of the overall center of gravity. Compared with the existing technology where the center of gravity is fixed and cannot be adjusted according to changes in working conditions, this invention can actively change the position of heavy components on the measuring arm 20 according to the needs of two different working conditions: bottom observation and surfacing recovery. This allows the single device to obtain the optimal center-of-gravity configuration in different working stages. Moreover, the center-of-gravity adaptive adjustment mechanism is built into the measuring arm 20, without increasing the external volume and upstream area of ​​the entire device, and without affecting the hydrodynamic characteristics of the device. The drive components are electrically controlled and can be remotely controlled underwater without additional mechanical operation, making the adjustment process simple and reliable.

[0047] In one embodiment of the present invention, the center of gravity adaptive adjustment mechanism has a bottom-sitting observation mode and an upward recovery mode.

[0048] In the bottom-mounted observation mode, the electronics compartment 30, battery compartment 40, and / or magnetic sensor 60 are located at the end of the measuring arm away from the float.

[0049] In the buoy recovery mode, the electronics compartment 30, battery compartment 40 and / or magnetic sensor 60 move to the end of the float.

[0050] In bottom-sitting observation mode, the drive assembly pushes heavy components such as the battery compartment 40 and electronics compartment 30 along the guide rail to the outermost end of the measuring arm 20. Since the measuring arm 20 is located at the bottom of the instrument and extends outwards in a horizontal or near-horizontal position, the vertical height of the instrument's center of gravity is minimized after the heavy components move to the outermost end of the measuring arm 20. At this point, the instrument possesses a very large stabilizing torque. Even under the horizontal scouring force of the undercurrent, the instrument's gravitational torque can effectively resist the overturning torque generated by the scouring, ensuring that the instrument will not tilt or tip over. The lower the center of gravity, the greater the stabilizing torque and the stronger the resistance to undercurrents.

[0051] In surfacing and recovery mode, the drive assembly pulls heavy components such as the battery compartment 40 and electronics compartment 30 back along the guide rail to a position near the root of the measuring arm 20 close to the float 10. At this time, the mass of the entire instrument is concentrated towards the float, and the center of gravity shifts upward, but remains below the center of buoyancy. When the center of buoyancy is higher than the center of gravity, if the instrument tilts due to any slight disturbance, the buoyancy and gravity create a restoring torque, causing the instrument to automatically return to a vertical attitude. This attitude ensures that the device moves upward with minimal updraft area during surfacing, reducing lateral drift.

[0052] By configuring the adaptive center of gravity adjustment mechanism to have both a bottom-sitting observation mode and an ascent and recovery mode, and by positioning the heavy component at the end of the measuring arm 20 away from the float 10 in the bottom-sitting observation mode and moving the heavy component to the end closer to the float 10 in the ascent and recovery mode, the optimal configuration of the overall center of gravity is achieved in both operating conditions. Compared with the fixed center of gravity scheme in the prior art, this invention, by actively changing the position of the component on the measuring arm 20, enables the device to obtain an extremely low center of gravity during the bottom-sitting phase to resist bottom current disturbances, and to obtain a stable floating attitude with the center of buoyancy higher than the center of gravity during the ascent phase to ensure vertical ascent, significantly improving the adaptability of the device to all operating conditions.

[0053] In one embodiment of the present invention, the measuring arm 20 is connected to the float 10 via a hinge; the measuring arm 20 has an extended state and a folded state that rotate relative to the float 10; the measuring arm 20 is in the extended state when bottoming out for observation, and in the folded state when surfacing for recovery (e.g., ...). Figure 2 (As shown); when the measuring arms 20 are in the folded state, multiple measuring arms 20 are folded together and attached to the side of the float.

[0054] A hinge connection refers to the rotatable connection between the measuring arm 20 and the float 10 via a hinge (or pivot). The hinge allows the measuring arm to rotate relative to the float 10 within a certain angular range about its hinge axis. A hinge typically includes a hinge seat fixed to the float 10, a hinge arm fixed to the measuring arm 20, and a hinge shaft connecting the two. The hinge connection is the fundamental structure enabling the folding function of the measuring arm 20.

[0055] The extended state is when the measuring arm 20 extends outward to its working position, at which point the measuring arm 20 and the float 10 form a certain angle (usually close to horizontal or a preset angle determined by the design). The electrode 50 is located at the end of the measuring arm, satisfying the electrode spacing and sensor layout requirements. The folded state is when the measuring arm 20 is folded to the side of the float 10, at which point the angle between the measuring arm 20 and the float 10 is small, and the measuring arm 20 is close to the float 10.

[0056] When the instrument is on the seabed for observation, the measuring arm 20 needs to be deployed to provide sufficient electrode spacing. A larger electrode spacing results in a larger amplitude of the measurable electric field signal and a higher signal-to-noise ratio. Therefore, the measuring arm 20 should remain deployed while on the seabed. However, during ascent and recovery, the deployed measuring arm 20 creates a large surface area facing the current. This surface area generates significant fluid resistance during the instrument's ascent, severely limiting its ascent speed. Furthermore, the non-streamlined shape in the deployed state can cause the instrument to rotate and drift during ascent, increasing the difficulty of the search.

[0057] The measuring arm 20 is rotatable relative to the float 10 via a hinge connection. It extends to the working position when bottoming out and folds back to the side of the float 10 during surfacing and recovery. The hinge connection is simple and reliable, requiring no complex drive mechanism. The measuring arm 20 can automatically switch between deployment and folding under the influence of gravity or buoyancy. When bottoming out, the measuring arm 20 remains deployed under the combined action of its own weight and the buoyancy of the float 10; during surfacing and recovery, the measuring arm 20 automatically folds back under the action of water resistance or a pre-set elastic element, resulting in a compact and streamlined overall design.

[0058] In one embodiment of the present invention, the structural component further includes a release mechanism and a counterweight; the release mechanism is connected to the counterweight, and after the counterweight is released, the measuring arm automatically switches from an unfolded state to a folded state under the action of buoyancy.

[0059] The release mechanism is a device that uses the principle of electrochemical corrosion to achieve the release action. Its working principle is as follows: when the counterweight needs to be released, electricity is applied to the release mechanism. The easily corroded components in the release mechanism (usually metal wires or sheets) undergo electrochemical corrosion in seawater and break, thereby releasing the counterweight connected to them. The release mechanism is a mature release method widely used in seabed observation instruments, with advantages such as high reliability, low impact, and low power consumption.

[0060] Counterweights are weights that provide negative buoyancy to the device, ensuring it sinks to the seabed and remains stable. The mass of the counterweight must be designed based on the overall net buoyancy and seabed stability requirements of the device, and they are typically made of cement blocks or other high-density materials. The counterweight is suspended from the bottom of the device and, after deployment, enables the device to overcome buoyancy and sink to the seabed.

[0061] Before the release mechanism is activated, the counterweight is suspended from the bottom of the machine via the release mechanism; after the release mechanism is activated, the counterweight detaches from the machine. Specifically, when the counterweight is suspended from the bottom of the machine, its gravity pulls the machine downwards, and the measuring arm 20 remains extended under the combined action of gravity and bottom support. When the counterweight is released, the total weight of the machine is reduced, the net buoyancy of the float 10 causes the machine to begin to float, and water resistance or a preset elastic restoring force causes the measuring arm to rotate around the hinge, automatically folding and retracting.

[0062] In one embodiment of the present invention, the battery compartment 40 is a modular and expandable battery compartment that is detachably installed inside the measuring arm 20.

[0063] Modular design means that the battery compartment 40 uses a unified standard interface and external dimensions, allowing it to be installed, disassembled, and replaced as an independent functional module. Expandability means that the number of battery compartment modules can be flexibly increased or decreased according to operational needs; that is, the device can install one or more battery compartment modules. This modular and expandable design enables the device to flexibly configure the total battery capacity according to the endurance requirements of different observation missions.

[0064] Submarine electromagnetic observation missions have varying endurance requirements: shallow structural studies may only require a few days of continuous observation, while deep mantle structure studies may require months or even a year of continuous recording. Existing instruments have fixed battery compartment locations and non-adjustable capacities. Their designs can only configure batteries according to the longest endurance requirements, leading to excess battery capacity in short-cycle missions, unnecessarily increasing overall weight and size; or, configuring batteries according to conventional endurance requirements, resulting in insufficient battery capacity in long-cycle missions. By designing the battery compartment as a modular and expandable structure, the battery compartment 40 can be detachably installed inside the measuring arm 20. The measuring arm 20 has cavities to accommodate the battery compartment 40; the length and number of these cavities determine the maximum number of battery compartment modules that can be installed. Before actual operation, operators calculate the total power required based on mission requirements, then select the appropriate number of battery compartment modules and install them one by one into their designated positions inside the measuring arm 20, connecting them to the electronics compartment 30 via electrical interfaces. If ultra-long-cycle observation is required, as many battery compartment modules as possible can be installed in each measuring arm 20; if only short-cycle observation is required, the number of battery compartment modules should be reduced to reduce the overall weight and deployment cost.

[0065] Please see Figure 3 and Figure 4 In one embodiment of the present invention, the magnetic sensor 60 is an inductive magnetic sensor; the inductive magnetic sensor includes: a first inductive magnetic sensor 601 and a second inductive magnetic sensor 602; the first inductive magnetic sensor 601 and the second inductive magnetic sensor 602 are disposed on different measuring arms 20.

[0066] An inductive magnetic sensor (also known as an electromagnetic induction magnetic sensor or an induction coil magnetic sensor) is a sensor that uses Faraday's principle of electromagnetic induction to detect changes in magnetic fields.

[0067] To measure the magnetic field components (Hx and Hy) in two orthogonal directions within a horizontal plane, two inductive magnetic sensors are required. A first inductive magnetic sensor 601 measures the magnetic field component Hx in one horizontal direction (e.g., north-south), and a second inductive magnetic sensor 602 measures the magnetic field component Hy in another horizontal direction (e.g., east-west). Together, the two sensors achieve a two-dimensional vector measurement of the horizontal magnetic field.

[0068] Please see Figure 5 and Figure 6 In one embodiment of the present invention, the magnetic sensor 60 is a fluxgate sensor 603.

[0069] The fluxgate sensor 603 (also known as a fluxgate magnetometer) is a sensor that uses the saturation characteristics of a high-permeability iron core under alternating excitation magnetic field to measure DC or low-frequency magnetic fields.

[0070] The main advantage of the fluxgate sensor 603 over the inductive magnetic sensor is its small size and light weight. Since the magnetic sensor needs to be embedded inside the measuring arm 20, the smaller fluxgate sensor occupies less internal space in the measuring arm 20, allowing the measuring arm 20 to be designed to be thinner and lighter, or to leave more space for other components (such as the battery compartment), such as the battery compartment 40 which can be mounted on two measuring arms 20.

[0071] In one embodiment of the present invention, the number of battery compartments 40 is at least two, and they are disposed on different measuring arms 20.

[0072] Because the fluxgate sensor 603 is small in size and light in weight, it occupies less space inside the measuring arm 20, and the space and weight saved can be used to install more battery compartment modules.

[0073] With the fluxgate sensor 603 configured, the number of battery compartments 40 is set to at least two, distributed across different measuring arms 20. On one hand, at least two battery compartments 40 provide a larger total battery capacity, effectively extending the device's endurance and meeting the requirements of ultra-long-term observation. On the other hand, distributing multiple battery compartments 40 across different measuring arms 20 ensures that the mass is roughly balanced across the four measuring arms, avoiding the center of gravity imbalance caused by concentrating all batteries on one arm, and guaranteeing the overall mass symmetry and attitude stability of the device.

[0074] In one embodiment of the present invention, there are four measuring arms 20, which are arranged in a cross shape, with an included angle of 90° between adjacent measuring arms.

[0075] By setting four measuring arms 20 arranged in a cross shape with adjacent arms at a 90° angle, the synchronous measurement of electric and magnetic field components in two orthogonal directions in the horizontal plane is achieved, meeting the basic requirement of the magnetotelluric sounding method for synchronous acquisition of orthogonal electromagnetic field components. The cross-shaped distribution ensures the structural symmetry and mass balance of the whole machine in the horizontal plane. No matter how the bottom current direction changes, the stress state of the device remains symmetrical, with no weak direction, further enhancing its resistance to bottom current. The four measuring arms 20 provide four independent internal cavities for embedding the electronic compartment 30, battery compartment 40, and magnetic sensor 60, respectively, providing a structural basis for the distributed arrangement of each component and optimized space utilization.

[0076] The process of performing seabed electromagnetic observations using the aforementioned device is described below, including the following steps:

[0077] 1. Before launching the device, configure the number of battery compartment modules according to the requirements of the operation task, complete the self-test of each module's functions, and import the coordinates of the operation station and the collected parameters.

[0078] 2. After the device is deployed to the seabed at the designated station, the measuring arm extends to the working position under the action of gravity, the electrodes form good electrical contact with the seabed sediments, and the magnetic sensor is kept away from the platform body to reduce electromagnetic interference.

[0079] 3. Start data acquisition and record electric and magnetic field signals according to the preset sampling rate and gain. During acquisition, the low center of gravity design ensures the instrument's attitude stability under undercurrent scouring.

[0080] 4. After the single-station observation task is completed, the release mechanism is powered on and the cement block counterweight is thrown away; the measuring arm automatically folds and retracts under the action of buoyancy, the fluid resistance of the whole machine is greatly reduced, and it quickly floats to the sea surface.

[0081] 5. After recovery and salvage, move to the next station to repeat the above steps as needed, or complete all operations.

[0082] In summary, the advantages of this invention are:

[0083] (i) Strong resistance to bottom currents: By embedding heavy components such as the electronic compartment and battery compartment into the bottom measuring arm in a conformal design and flattened layout, the center of gravity of the whole machine is significantly lowered, effectively resisting the overturning moment caused by the bottom current, and ensuring the attitude stability and data reliability of long-term observation.

[0084] (ii) Fast ascent and recovery speed. The foldable measuring arm automatically retracts during recovery, which greatly reduces the frontal area and fluid resistance, significantly improves the ascent speed, shortens the recovery time of a single device, and reduces the risk of instrument drift and loss.

[0085] (iii) High structural integration: The integrated design of "components as structure" eliminates redundant space between functional components and load-bearing structures. Magnetic sensors, electronic compartments, and battery compartments are embedded in the measuring arm, and the electrodes also serve as structural load-bearing components. The overall size of the machine is greatly reduced, which facilitates deployment and recovery operations at sea.

[0086] (iv) Strong endurance: The modular and expandable design of the battery compartment embedded in the measuring arm allows for flexible configuration of battery capacity according to operational needs; the miniaturization of the fluxgate cabin saves weight quota for battery expansion, meeting the needs of ultra-long-term continuous observation.

[0087] (v) High operational efficiency, rapid ascent and recovery significantly shortens the recovery time of a single device, reduces the time occupied by the mother ship and the dependence on large mechanical equipment, and is suitable for the efficient operation of large-scale seabed electromagnetic observation arrays.

[0088] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device, characterized in that, include: Structural components and electronic components; The structural components include: a float, a measuring arm, a counterweight, and a release mechanism; The electronic components include: an electronics compartment, a battery compartment, electrodes, and a magnetic sensor; The measuring arm is connected to the float; the release mechanism is connected to the counterweight. The electronic compartment, the battery compartment, and the magnetic sensor are embedded inside the measuring arm, and the electrode is installed at the end of the measuring arm away from the float. The battery compartment, the electrodes, and the magnetic sensor are all electrically connected to the electronics compartment.

2. The highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device as described in claim 1, characterized in that, It also includes: a center of gravity adaptive adjustment mechanism; The center of gravity adaptive adjustment mechanism is disposed inside the measuring arm; The adaptive center of gravity adjustment mechanism includes a guide rail and a drive assembly; the electronic compartment, the battery compartment and / or the magnetic sensor are mounted on the guide rail, and the drive assembly is used to drive the electronic compartment, the battery compartment and / or the magnetic sensor to move along the length direction of the measuring arm.

3. The highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device as described in claim 2, characterized in that, The adaptive center of gravity adjustment mechanism has a bottom-sitting observation mode and an upward recovery mode; In the bottom-mounted observation mode, the electronics compartment, the battery compartment, and / or the magnetic sensor are located at the end of the measuring arm away from the buoy. In the buoy recovery mode, the electronics compartment, the battery compartment, and / or the magnetic sensor move to the end of the float.

4. The highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device as described in claim 1, characterized in that, The measuring arm is connected to the float via a hinge; The measuring arm has an extended state and a folded state that rotate relative to the float; The measuring arm is in the unfolded state when it is on the bottom for observation and in the folded state when it is floating and retracted. In the folded state, multiple measuring arms are retracted and fitted against the side of the float.

5. The highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device as described in claim 4, characterized in that, The release mechanism is connected to the counterweight. After the counterweight is released, the measuring arm automatically switches from the unfolded state to the folded state under the action of buoyancy.

6. The highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device as described in claim 1, characterized in that, The battery compartment is a modular and expandable battery compartment that is detachably installed inside the measuring arm.

7. The highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device as described in claim 1, characterized in that, The magnetic sensor is an inductive magnetic sensor; The inductive magnetic sensor includes: a first inductive magnetic sensor and a second inductive magnetic sensor. The first inductive magnetic sensor and the second inductive magnetic sensor are mounted on different measuring arms.

8. The highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device as described in claim 1, characterized in that, The magnetic sensor is a fluxgate sensor.

9. The highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device as described in claim 8, characterized in that, The number of battery compartments is at least two, and they are mounted on different measuring arms.

10. The highly reliable, long-endurance, seabed-based, self-contained electromagnetic observation device as described in claim 1, characterized in that, There are four measuring arms, which are arranged in a cross shape, with an included angle of 90° between adjacent measuring arms.

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