Submarine dipole-dipole electromagnetic detection system and method carried on remote control underwater robot

Abstract

The invention discloses a seabed dipole-dipole electromagnetic detection system and method carried on a remote control underwater robot, and belongs to the technical field of seabed metal mineral resource fine exploration. The system comprises a remote control underwater robot (ROV), a retractable receiving coil extension bracket, a transient electromagnetic transmitting coil, a transient electromagnetic receiving coil, a transient electromagnetic main engine room and an instrument fixing bracket. The extension bracket is controlled through the hydraulic retraction device, so that the receiving coil is arranged away from the ROV body, and the interference of the equipment body on electromagnetic signals is obviously reduced. The ROV performs low-altitude cruising on the seabed along a preset fine measuring line to acquire transient electromagnetic data, and the actually measured data is corrected in real time by using the full-space seawater environment response in the diving process, so that the system interference is effectively inhibited. According to the method, the high-resolution electromagnetic detection capability of ore bodies such as seabed polymetallic sulfide is improved, and the method is suitable for mineral resource investigation of complex terrains and small-scale regions.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic exploration of metal resources such as seabed polymetallic sulfides, and specifically to a seabed dipole-dipole electromagnetic detection system and method carried by a remote-controlled underwater robot. Background Art

[0002] Seafloor polymetallic sulfide deposits found along mid-ocean ridges are rich in metals such as copper, zinc, silver, and gold, and represent a significant seafloor mineral resource. There is an urgent need for effective electromagnetic exploration methods to characterize the three-dimensional distribution of seafloor polymetallic sulfides and, based on this, to quantitatively assess their resources. Due to the high conductivity of seawater and the complex topography of mid-ocean ridges, current transient electromagnetic (TEM) towed acquisition methods experience significant instrument attitude fluctuations and high altitudes above the bottom. These instruments are also susceptible to sea conditions, causing the towed instrument to deviate from the designed survey line. Furthermore, for small seafloor polymetallic sulfide deposits, dense and detailed survey lines are difficult to achieve, compromising TEM performance. Therefore, to obtain high-quality near-bottom TEM data, it is necessary to consider integrating TEM equipment with near-bottom mobile platforms, such as remotely operated vehicles (ROVs), while minimizing interference from the mobile platforms themselves on data acquisition.

[0003] To overcome these shortcomings, researchers both domestically and internationally have recently explored the use of remotely operated underwater vehicles (ROVs) or autonomous underwater vehicles (AUVs) as mobile vehicles for transient electromagnetic surveys. ROVs possess excellent maneuverability and precise control off the bottom, enabling them to operate close to the seabed or even hover. They also allow for flexible deployment of high-density survey lines, significantly improving spatial resolution. Technical reports and experiments from several international publications (e.g., GEOMAR, NIOT, and others) have demonstrated that modularizing electromagnetic transmitters and receivers on ROVs has enabled preliminary identification of typical sulfide ore bodies. However, due to the extensive integration of metal materials, propulsion systems, and various electrical equipment within the ROV itself, electromagnetic interference is more prominent than with traditional towed systems. Without effective isolation and correction mechanisms, data quality will be severely limited. Furthermore, the limited space on the ROV platform places higher demands on the weight, size, and layout of the survey equipment.

[0004] Therefore, there is an urgent need to develop a transient electromagnetic detection system and supporting methods for precise electromagnetic exploration of seafloor metal sulfides and other mineral resources that can fully utilize the advantages of ROVs' near-bottom precision operations and high maneuverability, while effectively suppressing electromagnetic interference from the vehicle itself, improving the signal-to-noise ratio, and enhancing the reliability of data interpretation. This provides the technical foundation and practical needs for the proposal of this invention. Summary of the Invention

[0005] The purpose of the present invention is to address the problem of insufficient precision of conventional towed transient electromagnetic surveys in the above-mentioned seabed resource surveys, as well as the problem of carrier electromagnetic interference unique to transient electromagnetic exploration operations, and to propose a seabed dipole-dipole electromagnetic detection system and method mounted on a remote-controlled underwater robot suitable for small-scale fine survey operations.

[0006] The object of the present invention will be achieved through the following technical solutions: the system comprises: a remote-controlled underwater robot ROV, a receiving coil extension bracket, a transient electromagnetic transmitting coil, a transient electromagnetic receiving coil, a transient electromagnetic main cabin and an instrument fixing bracket; The receiving coil extension bracket group consists of two brackets and a hydraulic contraction device, including an extension bracket, an extension bracket and a hydraulic contraction device. The extension bracket is installed on the left side of the middle of the ROV, and the extension bracket is installed on the right side of the middle of the ROV. The hydraulic contraction device is installed at the root of the extension bracket to realize the extension and retraction of the extension bracket; The transient electromagnetic transmitting coil is installed on the chassis of the ROV body; the transient electromagnetic receiving coils are respectively installed on the extension brackets; the transient electromagnetic main cabin is connected to the transient electromagnetic transmitting coil, the transient electromagnetic receiving coil group and the ROV body through a watertight cable, and the specific installation position of the transient electromagnetic main cabin is adjusted according to the ROV counterweight state; The transient electromagnetic receiving coil is installed and fixed through an instrument fixing bracket.

[0007] In one solution, the extension bracket and transient electromagnetic receiving coil are installed symmetrically along the left and right sides of the ROV, reducing the electromagnetic interference generated by the ROV body to the transient electromagnetic detection signal and ensuring the smooth operation of the ROV underwater; the transient electromagnetic transmitting coil is installed on the ROV body chassis to reduce the burden of the ROV underwater movement while ensuring the signal transmission of a large magnetic moment.

[0008] In one embodiment, the instrument fixing bracket is composed of U-shaped semicircular fixing plates, and the transient electromagnetic transmitting coil is fixed between the U-shaped plates by fixing bolts and further installed on the extension bracket.

[0009] In one solution, the extension bracket, the instrument fixing bracket, and the fixing bolt 10 are all made of high-strength and lightweight non-metallic materials.

[0010] In one scheme, the transient electromagnetic device is connected to ROV1 via a watertight cable, and the ROV is further connected to the research vessel via an armored cable to ensure power supply and data transmission, so that real-time data monitoring can be carried out on the deck unit of the research vessel during underwater operations.

[0011] In another aspect, a transient electromagnetic detection method and a full-space water body data correction method carried by a remote-controlled underwater robot are provided. The method is applicable to the system described above and comprises the following steps: S1: Before launching the remote-controlled underwater robot (ROV), after checking all transient electromagnetic components and ensuring they are correct, power on the transient electromagnetic deck test to confirm that the detection function and hydraulic retraction function are normal; wait until the research vessel reaches the starting position of the operation, ensure that the extension bracket and the extension bracket are in the retracted state, and then lower the ROV; S2: When the ROV is halfway down, the extension bracket and extension bracket 3 are opened by the hydraulic retraction device, and the continuous acquisition of the transient electromagnetic response of the water body in the entire space begins. This is used as the measured response in the uniform seawater medium for data correction in subsequent processing; S3: After the correction data collection is completed, the extension bracket is retracted through the hydraulic retraction device, and the ROV continues to dive to the starting point of the designed survey line; S4: Establish a uniform seawater conductivity model. Based on the information of the ROV transient electromagnetic operation, such as the transmitting current, coil pitch, transmitting radius and effective receiving area, perform forward simulation to derive the theoretical response of the ROV transient electromagnetic in a full seawater environment. S5: For the time series t= [t o ,t1,…,t n ], n is the number of sampling time points, and the full-space seawater correction coefficient is defined as:

[0012] Among them, P(t) is the theoretical transient electromagnetic response of the full-space uniform medium obtained by numerical simulation, and D(t) is the measured transient electromagnetic response of ROV1 in the full seawater environment.

[0013] In one scheme, the response characteristics of D(t) are considered to be affected only by the uniform seawater conductivity and the electromagnetic interference of the ROV body, and the correction coefficient S(n) is used to quantify the data interference. The expression for water body correction for the complete measured transient electromagnetic data set D(m,n) is:

[0014] Where m is the number of measurement points in the dataset; the full-space seawater correction coefficient is applied to the complete measured dataset, and the resulting corrected dataset D 校 On the basis of removing the interference of ROV1, the electromagnetic anomalies caused by the changes in the seabed conductivity structure are still retained.

[0015] In one embodiment, in S3, the extension bracket is extended by a hydraulic contraction device, the extension bracket is opened, and the ROV is allowed to perform transient electromagnetic detection along a pre-planned survey line.

[0016] Beneficial effects of the present invention: The transient electromagnetic equipment carried by the remote-controlled underwater robot (ROV) effectively overcomes the influence of sea conditions such as ocean currents, greatly improving the stability of the instrument. This ensures that the coil attitude remains stable during the measurement process and ensures the stability of the measuring line height above the bottom under complex seabed terrain conditions.

[0017] The remote-controlled robot ROV has an independent power system and positioning function, which enables the transient electromagnetic equipment to achieve small-area and small-scale detection, meeting the requirements of high-precision exploration.

[0018] Transient electromagnetic dipole-dipole detection based on the remote-controlled robot ROV can effectively reduce the electromagnetic interference caused by the ROV body to the transient electromagnetic signal reception, while ensuring the signal transmission of large magnetic moment, effectively increasing the transient electromagnetic detection capability.

[0019] By comparing the transient electromagnetic response of all seawater collected during actual operations with the theoretical transient electromagnetic response of uniform media, the interference characteristics of the measured data can be effectively quantified. By using the full-space water body data correction method, the electromagnetic interference of the detection equipment itself can be further reduced, while retaining effective anomalies and improving the signal-to-noise ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Of course, the drawings in the description are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 This is a schematic structural diagram of a seabed dipole-dipole electromagnetic detection system carried by a remote-controlled underwater robot according to the present invention; Figure 2 Schematic diagram of each component.

[0022] Figure 3 This is a schematic diagram of the instrument fixation.

[0023] Figure 4 This is a schematic diagram of a seabed dipole-dipole electromagnetic detection method carried by a remote-controlled underwater robot according to the present invention.

[0024] Figure 5 The survey line path is planned for ROV offshore operations, and the ROV conducts survey operations along the preset route.

[0025] Figure 6 This is a time-depth variation diagram of ROV offshore operations. In the near-bottom section, the ROV maintains a stable altitude above the bottom for cruising and detection operations.

[0026] Figure 7 Schematic diagram of the effect of the full-space water body data correction method.

[0027] In the figure: 1-remote control underwater robot ROV, 2-ROV left extension bracket, 3-ROV right extension bracket, 4-hydraulic telescopic device, 5-transient electromagnetic transmitting coil, 6-transient electromagnetic left receiving coil, 7-transient electromagnetic right receiving coil, 8-transient electromagnetic main cabin, 9-instrument fixing bracket, 10-fixing bolt, 11-research vessel, 12-deck unit, 13-armored cable, 14-float. DETAILED DESCRIPTION

[0028] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate exemplary embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those understood by those skilled in the art to which the present invention pertains. The terms used in the present specification are for the purpose of describing specific embodiments only and are not intended to limit the present invention. To facilitate understanding of the present invention, a more comprehensive description of the present invention will be provided below with reference to the accompanying drawings. Typical embodiments of the present invention are shown in the drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0030] Implementation Example 1 like Figure 1 As shown, the present invention provides a seabed dipole-dipole electromagnetic detection system carried by a remote-controlled underwater robot, which includes a remote-controlled underwater robot ROV1, receiving coil extension brackets 2 and 3, a hydraulic device 4, a transient electromagnetic transmitting coil 5, transient electromagnetic receiving coils 6 and 7, a transient electromagnetic main cabin 8 and an instrument fixing bracket 9.

[0031] The receiving coil extension bracket group consists of two brackets and a hydraulic contraction device. The two extension brackets are respectively installed on the left side and the right side of the middle part of the ROV. The hydraulic contraction device is installed at the root of the extension bracket to realize the extension and retraction of the extension bracket; the transient electromagnetic transmitting coil is installed on the ROV body chassis; the two transient electromagnetic receiving coils are respectively installed at the ends of the two extension brackets; the transient electromagnetic main cabin is connected to the transient electromagnetic transmitting coil, the transient electromagnetic receiving coil and the ROV body through a watertight cable, and the specific installation position of the transient electromagnetic main cabin is adjusted according to the ROV counterweight state; the transient electromagnetic receiving coil is fixedly installed by an instrument fixing bracket.

[0032] The two extension brackets and the two transient electromagnetic receiving coils are respectively installed symmetrically along the left and right sides of the ROV, reducing the electromagnetic interference generated by the ROV body to the transient electromagnetic detection signal and ensuring the smooth operation of the ROV underwater; the transient electromagnetic transmitting coil is installed on the ROV body chassis to reduce the burden of the ROV underwater movement while ensuring the signal transmission of a large magnetic moment.

[0033] The instrument fixing bracket is composed of a U-shaped semicircular fixing plate. The transient electromagnetic transmitting coil is fixed between the U-shaped plates by fixing bolts and is further installed on the extension bracket.

[0034] The receiving coil extension bracket, instrument fixing bracket and fixing bolts are all made of high-strength and lightweight non-metallic materials.

[0035] The transient electromagnetic device is connected to the ROV via a watertight cable, and the ROV is further connected to the research vessel via an armored cable to ensure power supply and data transmission, allowing real-time data monitoring on the research vessel during underwater operations.

[0036] This invention collects and tests the electromagnetic interference generated by the ROV1 in the laboratory. Without affecting the carrier's operation, it designs an extension bracket assembly to keep transient electromagnetic measurements away from ROV1 interference. Furthermore, to ensure the safety of equipment and personnel during the deployment and recovery of the ROV1, a hydraulic device is provided to keep the extension bracket retracted during non-operational periods. This system does not affect traditional ROV1 operations and can additionally acquire high-precision transient electromagnetic data near the seabed. Furthermore, the system can monitor electromagnetic data in real time, effectively ensuring data quality, improving the efficiency of marine surveys, and providing scientific data support for the delineation of seabed mining areas.

[0037] ROV body transient electromagnetic interference assessment A control group was set up to determine the interference range using the power on and off of ROV1, the operation and shutdown of the thruster, and the horizontal distance between the transient electromagnetic coil and ROV1 as variables. When ROV1 was not powered on, the transient electromagnetic signal would produce electromagnetic anomalies due to the ROV1's metal structure. This anomaly decreased as the horizontal distance between the transient electromagnetic receiving coil and ROV1 increased. Combined with the load-bearing capacity of the extension bracket itself, the extension bracket length was determined to ensure that the electromagnetic interference from ROV1 was insufficient to affect the transient electromagnetic data. When ROV1 was powered on, its transformer became the main interference source. Test data showed that the transient electromagnetic signal distortion caused by this interference source was stable over time, and the operation and shutdown of the thruster had no additional impact on the transient electromagnetic signal. Therefore, transient electromagnetic can still identify abnormal seabed resistivity structures.

[0038] Transient electromagnetic installation method like Figure 2As shown, the cable of the transient electromagnetic transmitting coil 5 is wound along the groove of the rectangular frame, and the entire frame is directly fixed to the chassis of the ROV1 body; the transient electromagnetic main cabin 8 has a total of five interfaces, including power supply and communication interfaces, which are connected to the ROV1 through watertight cables, two receiving interfaces are connected to the transient electromagnetic receiving coils 6 and 7 respectively through watertight cables, and one transmitting interface is connected to the transient electromagnetic transmitting coil through a watertight cable.

[0039] The installation position and length of the instrument bracket group are determined by the above-mentioned test: two extension brackets 2, 3 and two transient electromagnetic receiving coils 6, 7 are respectively installed symmetrically on the left and right sides of the middle of ROV1 to reduce the electromagnetic interference generated by the ROV1 body to the transient electromagnetic detection signal and ensure the smooth operation of ROV1 underwater; the hydraulic contraction device 4 is installed at the root of the extension brackets 2, 3 to realize the extension and retraction of the extension brackets; the transient electromagnetic transmitting coil 5 is installed to the chassis of the ROV1 body, which can reduce the burden of ROV1 underwater movement while ensuring the signal transmission of large magnetic moment; the transient electromagnetic receiving coils 6, 7 are respectively installed at the ends of the two extension brackets 2, 3; the transient electromagnetic main engine room 8 is connected to the transient electromagnetic transmitting coil 5, the transient electromagnetic receiving coils 6, 7 and the ROV1 body through a watertight cable, and the specific installation position of the transient electromagnetic main engine room 8 is adjusted according to the counterweight state of ROV1; the transient electromagnetic receiving coil is fixedly installed by the instrument fixing bracket 9. The extension brackets 2, 3, the instrument fixing bracket 9 and the fixing screws 10 should be made of high-strength and lightweight non-metallic materials to meet the use requirements of the submarine high-pressure environment while preventing additional electromagnetic interference.

[0040] Figure 3 Figure 1 is a schematic diagram of the installation of transient electromagnetic receiving coils 6, 7, instrument fixing bracket 9, and extension brackets 2, 3. First, the transient electromagnetic receiving coils 6, 7 are installed on the "U"-shaped instrument fixing bracket 9. The U-shaped diameter of the instrument fixing bracket 9 should match the diameter of the receiving coils 6, 7. Two U-shaped plates are used to clamp the grooves of the receiving coils 6, 7 and fix them with fixing bolts 10. After the receiving coils 6, 7 and the instrument fixing bracket 9 are installed, the instrument fixing bracket 9 is installed on the ends of the extension brackets 2, 3 using fixing screws 10.

[0041] Implementation Example 2 Based on the system of Example 1, a method for seabed transient electromagnetic detection and a method for full-space water body data correction carried by a remote-controlled underwater robot are constructed, such as Figure 4-Figure 7 As shown, the following steps are included: S1: ROV1 is connected to deck unit 12 on research vessel 11 via armored cable 13, which is fitted with a float 14. Before launching, all transient electromagnetic (TEM) components must be inspected and verified. Power on the TEM and perform a deck test to ensure proper detection and hydraulic retraction functions. Once the research vessel reaches the launch location, ensure extension brackets 2 and 3 are retracted, and then lower ROV1.

[0042] S2: When ROV1 is halfway down (the distance between ROV1 and the seabed and the sea surface is much greater than the transient electromagnetic detection distance), the extension brackets 2 and 3 are opened by the hydraulic retraction device 4, and the continuous acquisition of the transient electromagnetic response of the seawater in the entire space is started. After the correction data acquisition is completed, the extension brackets 2 and 3 are retracted by the hydraulic retraction device 4, and ROV1 continues to dive to the starting point of the designed survey line.

[0043] S3: The extension bracket 2 and the extension bracket 3 are opened by the hydraulic contraction device 4 and the ROV 1 is allowed to perform transient electromagnetic detection along the pre-planned survey line (such as Figure 5 As shown in the figure, the research vessel 11 is kept in dynamic positioning and moves slowly to maintain the coordinated operation with ROV1. ROV1 moves forward at a constant speed of 0.5 to 1 knots, and adjusts the height above the bottom in real time according to the data of ROV1 altimeter during the process (as shown in the figure). Figure 6 (as shown), ensuring that the ROV remains close to the seabed surface during transient electromagnetic detection. After completing the survey line inspection, the hydraulic retraction device 4 retracts the extension brackets 2 and 3, recovering the ROV 1 to the deck of the research vessel 11.

[0044] S4: Establish a uniform medium model of seawater conductivity (~3S / m). Based on the emission current, emission radius, and effective receiving area of ​​the ROV transient electromagnetic operation dives, perform forward simulation to derive the theoretical response of the ROV transient electromagnetic in a full seawater environment.

[0045] S5: For the time series t= [t o ,t1,…,t n ], n is the number of sampling time points, and the full-space seawater correction coefficient is defined as:

[0046] Where P(t) is the theoretical transient electromagnetic response of a fully homogeneous medium obtained from numerical simulation, and D(t) is the measured transient electromagnetic response of the ROV1 in a full seawater environment. The response characteristics of D(t) can be considered to be affected only by the uniform seawater conductivity and the electromagnetic interference of the ROV1 itself. Therefore, the correction coefficient S(n) is used to quantify the data interference. The expression for water correction for the complete measured transient electromagnetic data set D(m,n) is:

[0047] Where m is the number of measurement points in the dataset. The full-space seawater correction coefficient is applied to the complete measured dataset, and the resulting corrected dataset D 校 On the basis of removing the interference of ROV1, the electromagnetic anomaly caused by the change of seabed conductivity structure is still retained ( Figure 7 ).

[0048] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing related hardware through a computer program. The program can be stored in a computer-readable storage medium, and when executed, the program can include the processes in the above-described method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0049] It should be understood that the detailed description of the technical solutions of the present invention using the preferred embodiments above is illustrative and not restrictive. A person skilled in the art, after reading the present specification, may modify the technical solutions described in the embodiments or replace some of the technical features therein with equivalents; such modifications or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A seabed dipole-dipole electromagnetic detection system mounted on a remote-controlled underwater robot, characterized by: The system comprises: a remote-controlled underwater robot (ROV), a receiving coil extension bracket, a transient electromagnetic transmitting coil, a transient electromagnetic receiving coil, a transient electromagnetic main cabin and an instrument fixing bracket; The receiving coil extension bracket group consists of two brackets and a hydraulic retraction device, including an extension bracket, an extension bracket and a hydraulic retraction device. The extension bracket is installed on the left side of the middle of the ROV, and the extension bracket is installed on the right side of the middle of the ROV. The hydraulic retraction device is installed at the root of the extension bracket to realize the extension and retraction of the extension bracket; The transient electromagnetic transmitting coil is installed on the chassis of the ROV body; the transient electromagnetic receiving coils are respectively installed on the extension brackets; the transient electromagnetic main cabin is connected to the transient electromagnetic transmitting coil, the transient electromagnetic receiving coil group and the ROV body through a watertight cable, and the specific installation position of the transient electromagnetic main cabin is adjusted according to the ROV counterweight state; The transient electromagnetic receiving coil is installed and fixed through an instrument fixing bracket.

2. The seabed dipole-dipole electromagnetic detection system carried by a remote-controlled underwater robot according to claim 1, characterized in that: The extension bracket and transient electromagnetic receiving coil are installed symmetrically along the left and right sides of the ROV, reducing the electromagnetic interference generated by the ROV body to the transient electromagnetic detection signal and ensuring the smooth operation of the ROV underwater; the transient electromagnetic transmitting coil is installed on the ROV body chassis to reduce the burden of the ROV underwater movement while ensuring the signal transmission of a large magnetic moment.

3. The seabed dipole-dipole electromagnetic detection system carried by a remote-controlled underwater robot according to claim 1, characterized in that: The instrument fixing bracket is composed of U-shaped semicircular fixing plates. The transient electromagnetic transmitting coil is fixed between the U-shaped plates by fixing bolts and is further installed on the extension bracket.

4. The seabed dipole-dipole electromagnetic detection system carried by a remote-controlled underwater robot according to claim 3, characterized in that: The extension bracket, the instrument fixing bracket, and the fixing bolt 10 are all made of high-strength and lightweight non-metallic materials.

5. The seabed dipole-dipole electromagnetic detection system carried by a remote-controlled underwater robot according to claim 1, characterized in that: The transient electromagnetic device is connected to ROV1 via a watertight cable, and the ROV is further connected to the research vessel via an armored cable to ensure power supply and data transmission, allowing real-time data monitoring on the deck unit of the research vessel during underwater operations.

6. A method for seafloor dipole-dipole electromagnetic detection carried by a remote-controlled underwater robot, the method being applicable to the system according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: S1: Before launching the remote-controlled underwater robot (ROV), after checking all transient electromagnetic components and ensuring they are correct, power on the transient electromagnetic deck test to confirm that the detection function and hydraulic retraction function are normal; wait until the research vessel reaches the starting position of the operation, ensure that the extension bracket and the extension bracket are in the retracted state, and then lower the ROV; S2: When the ROV is halfway down, the extension bracket and extension bracket 3 are opened by the hydraulic retraction device, and the continuous acquisition of the transient electromagnetic response of the water body in the entire space begins. This is used as the measured response in the uniform seawater medium for data correction in subsequent processing; S3: After the correction data collection is completed, the extension bracket is retracted through the hydraulic retraction device, and the ROV continues to dive to the starting point of the designed survey line; S4: Establish a uniform seawater conductivity model. Based on the emission current, coil pitch, emission radius, and effective receiving area of ​​the ROV transient electromagnetic operation dive, perform forward simulation to derive the theoretical response of the ROV transient electromagnetic in a full seawater environment. S5: For the time series t= [t o ,t1,…,t n ], n is the number of sampling time points, and the full-space seawater correction coefficient is defined as: ； Among them, P(t) is the theoretical transient electromagnetic response of the full-space uniform medium obtained by numerical simulation, and D(t) is the measured transient electromagnetic response of ROV1 in the full seawater environment.

7. The method for seabed dipole-dipole electromagnetic detection carried by a remote-controlled underwater robot according to claim 6, characterized in that: The response characteristics of D(t) are considered to be affected only by the uniform seawater conductivity and the electromagnetic interference of the ROV body, and the correction coefficient S(n) is used to quantify the data interference. The expression for water body correction for the complete measured transient electromagnetic data set D(m,n) is: ； Where m is the number of measurement points in the data set; the full-space seawater correction coefficient is applied to the complete measured data set, and the corrected data set D is obtained. 校 On the basis of removing the interference of ROV1, the electromagnetic anomalies caused by the changes in the seabed conductivity structure are still retained.

8. The method for seabed dipole-dipole electromagnetic detection carried by a remote-controlled underwater robot according to claim 6, characterized in that: In the above-mentioned S3, the extension bracket is opened by a hydraulic contraction device, and the ROV is allowed to perform transient electromagnetic detection along the pre-planned survey line.

Images