Aviation transient electromagnetic system and method

Abstract

The invention relates to the technical field of geophysical exploration, and provides an aviation transient electromagnetic system and method. The system comprises a transmitting subsystem, a receiving subsystem, a transmitting loop bearing structure and a plurality of unmanned aerial vehicles, the multiple unmanned aerial vehicles are connected with the launching loop line bearing structure through the connecting pieces and are configured to be used for providing distributed lift force; the method comprises the following steps: providing a transmitting loop bearing structure to bear a transmitting loop of an aviation transient electromagnetic system; a plurality of unmanned aerial vehicles are adopted to be connected with a launching loop line bearing structure through connecting pieces, the unmanned aerial vehicles are cooperatively controlled, and distributed lift force is provided for the launching loop line bearing structure and a launching loop line, so that the launching loop line is deployed in the air; and transmitting an electromagnetic pulse through a transmitting loop, and receiving an electromagnetic response signal in different observation modes by using a sensor. The technical problem that an existing aviation transient electromagnetic system is difficult to implement large-magnetic-moment and multi-mode operation in a lift force limited environment can be solved.

Description

Technical Field

[0001] This application relates to the field of geophysical exploration technology, and requests protection for an airborne transient electromagnetic system and an airborne transient electromagnetic method. Background Technology

[0002] Electromagnetic methods are geophysical exploration methods based on the principle of electromagnetic induction. They utilize natural or artificial sources to excite the Earth and extract information about the underground electrical structure by observing the spatiotemporal distribution of the Earth's electromagnetic response. These methods are widely used in mineral and groundwater resource exploration, geological mapping, and environmental engineering. Electromagnetic methods are classified into two categories based on the nature of the response: methods that study the relationship between the Earth's steady-state response and frequency are called frequency-domain methods (FDEM), while methods that measure the Earth's transient response after the excitation pulse is turned off are called time-domain methods (TDEM) or transient electromagnetic methods (TEM). In principle, FDEM and TDEM are not fundamentally different, but they differ in specific exploration techniques to suit different needs. Traditional electromagnetic methods deploy the entire observation system on the ground. This approach is inefficient in areas such as the Gobi Desert, deserts, ravines, areas with dense water networks, and forest cover, making rapid, large-area coverage difficult. To address this, researchers proposed the airborne electromagnetic method (AEM). AEM methods can also be divided into frequency domain and time domain methods. Compared to airborne frequency domain systems, airborne time domain (ATEM) systems typically achieve larger emission magnetic moments and higher spectral resolution, making them more suitable for balancing operational efficiency and detection performance under airborne motion conditions. Therefore, AEM has become the main type of AEM detection system.

[0003] The platform on which an ATEM system is mounted is the fundamental factor determining its performance. In the early stages of ATEM technology development, both fixed-wing aircraft and helicopters were considered. However, due to the relatively weaker payload capacity and power supply of helicopters compared to fixed-wing aircraft, ATEM systems in the mid-to-late 20th century primarily used fixed-wing aircraft as their platform, forming the Fixed-wing aircraft-borne TEM system (FTEM). In terms of application, fixed-wing aircraft had high maintenance and upkeep costs, required airport access for takeoff and landing, and were difficult to conduct economically feasible exploration work in vast, underdeveloped regions. With the significant improvement in helicopter system performance, which could provide sufficient payload and power supply, since 2000, helicopter-based ATEM systems, namely Helicopter-borne TEM (HTEM), have begun to emerge in large numbers. The advantages of helicopters over fixed-wing aircraft, such as minimal aircraft modifications, no airport dependence for takeoff and landing, good low-speed ground-to-air performance, and relatively lower aircraft maintenance requirements, have become apparent. These advantages have significantly reduced the application and maintenance costs of the system, leading to HTEM gradually replacing FTEM as the primary solution for current ATEM systems.

[0004] Airborne transient electromagnetic methods (TEM) utilize electromagnetic detection equipment mounted on a flight platform to efficiently explore areas inaccessible to personnel and equipment, such as deserts, forests, and waterways. This technology is of significant technical importance in mineral resource exploration, groundwater investigation, and geological mapping. To meet these needs, the mainstream airborne TEM systems currently employ helicopters as their platform. Specifically, these systems typically use a single helicopter as the centralized lift source, towing a detection pod containing a large transmitting loop and receiving sensors beneath the fuselage. Helicopters, with their ability to operate without airports and their excellent low-altitude maneuverability, offer greater flexibility and cost-effectiveness compared to earlier fixed-wing aircraft solutions, making them the primary technology for current commercial applications.

[0005] However, the aforementioned technical solutions based on a single, centralized lift platform have inherent technical drawbacks. The detection depth of an airborne transient electromagnetic system is positively correlated with its emitted magnetic moment, and a larger emitted magnetic moment usually means a larger and heavier transmitter loop and power supply system are required. When operating in areas with thin air, such as high-altitude regions, the helicopter's payload capacity decreases significantly. This leads to an irreconcilable technical contradiction: to achieve deep detection in high-altitude areas, the system needs to maintain a large weight to ensure the emitted magnetic moment, but the helicopter, as the sole source of lift, cannot provide sufficient lift in this environment. Therefore, in practical applications, existing technical solutions face a difficult choice between "switching to a large, heavy-load helicopter with extremely high operating costs" or "sacrificing detection depth to reduce system weight," which greatly limits the effectiveness and economic viability of airborne transient electromagnetic technology in critical areas such as high-altitude regions. Summary of the Invention

[0006] To address the technical challenge of existing airborne transient electromagnetic systems struggling to perform large magnetic moment and multi-modal operations in lift-constrained environments, this application provides an airborne transient electromagnetic system. This application also relates to an airborne transient electromagnetic method.

[0007] This application provides an airborne transient electromagnetic system, comprising: The transmission subsystem includes a transmitter and a transmission loop; and A receiving subsystem, the receiving subsystem including a receiver and a sensor for sensing electromagnetic response signals; The airborne transient electromagnetic system also includes: A transmit loop support structure for supporting the transmit loop; and Multiple drones are connected to the transmit loop support structure via connectors and are configured to provide distributed lift in a coordinated manner to the transmit loop support structure, the transmit loop supported thereon, and a receiving topology consisting of at least one set of receiving subsystems.

[0008] Optionally, the transmit loop support structure is composed of multiple detachably connected tubular components, so that the size and / or shape of the transmit loop support structure can be adjusted according to detection requirements.

[0009] Optionally, the plurality of UAVs, in addition to the second type of UAV for carrying the transmission loop support structure, also include: a first type of UAV for carrying the transmitter and power module, and a third type of UAV for carrying the receiving subsystem; the number of the second and third types of UAVs is multiple.

[0010] Optionally, the plurality of UAVs maintain a predetermined formation configuration when carrying the launch return line.

[0011] Optionally, a receiving topology consisting of no less than one set of the receiving subsystems can be used to achieve different observation modes, and the multiple UAVs maintain a predetermined formation configuration when carrying the receiving topology.

[0012] Optionally, the first type of UAV is electrically connected to the transmission return line via a power supply cable. The power supply cable is equipped with a cable disconnection device, which is configured to automatically disconnect the electrical and mechanical connections when the tensile force it bears exceeds a preset threshold.

[0013] Optionally, the multiple UAVs are coordinated and controlled by a formation flight control system to actively maintain the attitude stability of the transmission loop support structure and / or the stability of the positional relationship between the sensor and the transmission loop during flight.

[0014] This application also provides an airborne transient electromagnetic method, comprising the following steps: Provide a transmit loop support structure to support the transmit loop of an airborne transient electromagnetic system; Multiple drones are connected to the transmitter loop support structure via connectors, and the drones are coordinated and controlled to provide distributed lift to the transmitter loop support structure and the transmitter loop, thereby deploying the transmitter loop in the air; and Electromagnetic pulses are emitted through the transmission loop, and electromagnetic response signals are received by sensors in different observation modes.

[0015] Optionally, the step of coordinating the control of the multiple drones includes performing terrain-following flight at a speed of less than 25 m / s.

[0016] Optionally, the method further includes: system reliability testing, which is conducted on the ground; before conducting flight detection, placing the receiving subsystem outside the transmission loop and maintaining the receiving subsystem at the measurement distance required for clear and effective signal reception; activating the transmission subsystem and observing the response signal characteristics collected by the receiving subsystem until it is determined that the receiving subsystem is in normal working condition.

[0017] Optionally, the method further includes the step of controlling the plurality of UAVs to raise the launch return line support structure to a height of over 1000 meters to collect background field data before or after the detection.

[0018] The advantages of this application compared to the prior art are: This invention breaks away from the conventional thinking of relying on a single lift source. It decomposes the total lift requirement and uses the combined lift of multiple UAVs to collectively support a physically continuous, large-scale detection payload, effectively solving the operational challenges of deep-penetration exploration in high-altitude regions. This structural approach enables lift scalability, making lift no longer a fixed value but a variable that can be configured as needed based on system weight. When the total system weight exceeds the payload of a single UAV, the lift increase requirement can be met simply by increasing the number of UAVs, thus making the deployment of large-scale magnetic moment systems in high-altitude areas possible, offering high flexibility and economy. Simultaneously, the receiving topology, constructed with at least one receiving subsystem, enables aerial gradient observation, which is impossible in traditional solutions, significantly improving the system's ability to distinguish underground targets.

[0019] This invention provides lift to the launch loop support structure by employing a multi-UAV collaborative mounting method. The launch loop is suspended from multiple points by multiple UAVs via cables, allowing for coordinated adjustment of their respective positions and tensions. Based on the coordinated formation changes of the multiple UAVs, the attitude of the launch loop can be actively controlled through a formation flight control system. This overcomes the technical shortcomings of existing suspension structures, which can only provide a single signal acquisition attitude and are prone to swaying with airflow during signal acquisition, ensuring the stability and consistency of the launch site. Furthermore, by actively controlling the working attitude of the launch loop, this invention effectively ensures that the launch loop maintains a near-horizontal attitude throughout flight, avoiding magnetic field distortion caused by tilting or deformation of the launch loop, thereby improving data quality and the reliability of inversion interpretation.

[0020] The present invention, employing the aforementioned structural scheme, supports a superior flight mode, enabling lower and slower terrain-following flight. Low-speed flight allows for more transmit / receive cycles per unit distance, thereby achieving higher data density and horizontal resolution.

[0021] This invention employs a cable disconnection device in the power cable connecting the first type of UAV to the transmission loop, which is equivalent to setting up a "mechanical fuse" for the cable that will automatically disconnect when a predetermined tension is reached. This can improve the operational safety of UAV aerial surveys. If the transmission loop accidentally gets caught on an obstacle, the relatively inexpensive transmission loop structure can be sacrificed by disconnecting the cable, thus isolating the remaining core modules and the entire UAV group from danger and helping to reduce economic losses caused by accidents.

[0022] This invention decomposes the entire ATEM system functionally and assigns these independent sub-functional modules to different UAVs. This allows sensitive sensors to be kept away from transmitters, power modules, and the main noise sources generated by multiple UAVs, which helps to improve the signal-to-noise ratio of the aviation transient electromagnetic system. By physically isolating the sensors, the electromagnetic interference and mechanical vibration caused by the noise signals are significantly reduced, resulting in "cleaner" observation data.

[0023] The present invention, by adopting the above-described structural design, further enhances system robustness, preventing the entire expensive system from crashing when a drone carrying a single functional module malfunctions. Furthermore, this structural design facilitates the selection of the most suitable drone model for different functional modules, helping to reduce drone procurement costs.

[0024] The airborne transient electromagnetic method provided by this invention disassembles a large and cumbersome detection system by employing a distributed, modular, and reconfigurable airborne transient electromagnetic system. It utilizes a formation of multiple UAVs to collaboratively complete geophysical exploration tasks. This invention overcomes the operational limitations of single, centralized lift platforms in lift-constrained areas such as high-altitude regions. By decoupling the core functional units of the system and assigning them to independent UAVs, the lift requirements of the heaviest transmission loop and mounting structure are distributed among multiple UAVs. Compared to traditional airborne transient electromagnetic systems, this method has a wider range of applications. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the aerospace transient electromagnetic system in this application.

[0026] Figure 2 This is a schematic diagram of the cable disconnection device configuration in this application.

[0027] Figure 3 This is a schematic diagram of one of the ground test scenarios in this application.

[0028] Figure 4 This is a schematic diagram of the sensor arrangement in one of the working scenarios of Embodiment 4 of this application; Figure 5 This is a schematic diagram of the sensor arrangement in another application scenario in Embodiment 4 of this application. Detailed Implementation

[0029] The following are examples of specific implementation processes provided to illustrate the technical solutions to be protected in this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can implement this application by different technical means under the guidance of the concept of this application. Therefore, this application is not limited to the specific embodiments below.

[0030] Example 1: like Figure 1 As shown, the present invention provides an airborne transient electromagnetic system, comprising: a transmitting subsystem 100, the transmitting subsystem 100 including a transmitter 110 and a transmitting loop 120; and a receiving subsystem 130, the receiving subsystem 130 including a receiver 131 and a sensor 132 for sensing electromagnetic response signals; the airborne transient electromagnetic system further includes: a transmitting loop support structure 200 for supporting the transmitting loop; and a plurality of unmanned aerial vehicles (UAVs) 300, the plurality of UAVs being connected to the transmitting loop support structure 200 via connectors 400 and configured to coordinately provide distributed lift to the transmitting loop support structure 200 and the transmitted loop 120 supported thereon.

[0031] Preferably, in the above structural scheme, the receiving topology consists of at least one receiving subsystem, and the configured UAVs are all used to provide distributed lift. It should be noted that using a single UAV equipped with a dedicated receiving subsystem to receive return signals improves detection accuracy and flexibility. Furthermore, using multiple UAVs, each equipped with the aforementioned receiving subsystem, to form a receiving topology further enhances detection accuracy. Therefore, both of these structural schemes are protected in this application.

[0032] The airborne transient electromagnetic system of this invention can be implemented by a control system, a flight command terminal, an electronics unit, and multiple airborne unmanned aerial vehicles (UAVs). It is suggested that a system controller be used as the main control and scheduling unit in the embodiments described below. The system controller can be a central processing unit integrated into a ground station or distributed on the UAVs, allowing the UAVs to exchange information and coordinate operations in real time via wireless communication. The airborne transient electromagnetic system of this invention consists of a transmitting subsystem, a receiving subsystem, a transmitting loop support structure, and a plurality of UAVs for providing lift. Schematic diagrams of the main structural units of the system are shown below. Figure 1 As exemplified. Where appropriate, the units are physically and functionally connected via flexible cables, wires, and data communication links.

[0033] Specifically, the transmitting subsystem includes a transmitter and a transmitting loop. The transmitter typically generates a predetermined excitation electromagnetic signal and, through the transmitting loop (also known as a transmitting antenna or excitation coil), produces a strong pulsed electromagnetic field below the ground surface to excite underground conductors. The transmitting loop is generally arranged around the periphery of the transmitting loop's supporting structure in the form of a multi-turn or single-turn coil. Specific conductor materials, such as copper cable or high-strength aluminum cable, can be selected, and the specific geometry can be a circle, a regular polygon, etc. The receiving subsystem includes a receiver and at least one set of sensors. The receiver is used for data acquisition and storage, and can perform preliminary on-site signal processing or digitization. The sensors can be electric field sensors or magnetic field sensors, either single-component or three-component, used to observe the electromagnetic field response generated by the ground under the excitation of the transmitted signal, and are configured according to the actual detection resolution and field quantity requirements. The sensors are typically arranged in a space far from the flight platform via insulating supports or pods to effectively reduce interference from the aircraft and power system on the observed signals, as further described in [reference needed]. Figure 1 The pod installation of the receiving subsystem shown.

[0034] One of the key structures of the system is the transmitter loop support structure, which provides mechanical support for the transmitter loop and observation sensors, maintaining them in the air at a specified attitude. The transmitter loop support structure is made of high-strength insulating materials (such as fiberglass, carbon fiber composite pipes, etc.) to ensure a reasonable balance between structural strength and self-weight, while providing fixation and electrical insulation for the transmitter loop. The transmitter loop support structure can be a regular polygon (such as a regular 16-sided polygon, a regular 12-sided polygon, etc.), with multiple UAV mounting points at the connection points of each side. Figure 1 The diagram shows the carrier structure of the transmitter loop, with the internal support component in the center and the mounting interface for connecting the UAV on the periphery.

[0035] Multiple drones provide distributed lift for the system. Each drone is connected to the launch loop support structure via fixed connectors such as elastic cables, vibration damping structures, and distributed at different nodes of the polygon, achieving even load distribution. Drones can be multi-rotor, fixed-wing hybrid, or vertical takeoff and landing (VTOL) types, selected based on a trade-off between the detection area environment, flight altitude, and total system load. Coordination between drones is achieved through coordinated scheduling by the system controller, maintaining the relative position, attitude, altitude, and safe distance of the drone group. Figure 1 The overall architecture of the aviation transient electromagnetic system is shown. The UAV continuously reports its status via a wireless link, and the system dynamically adjusts the thrust output of each UAV based on real-time calculations to achieve overall balance and stable flight of the launch loop support structure.

[0036] Before operation, the system controller automatically calculates the required number of UAVs and power supply based on the altitude of the detection area, weather conditions, estimated launch cable weight, and number of sensors, and rationally allocates mounting points. After assembly, electrical connections and system self-checks are performed on the ground, followed by a unified takeoff command and formation flight. Each UAV works together to counteract external disturbances such as airflow and wind loads, maintaining the horizontal attitude and specified altitude of the launch cable support structure. The system can automatically follow terrain changes to improve data consistency and detection accuracy.

[0037] The key custom terms in this system design are explained as follows: Transmitting Subsystem: Refers to all parts of the system capable of generating an excitation electromagnetic field, including the transmitter and transmission loop, and may include integrated or separate modular arrangements; Receiving Subsystem: Refers to all signal receiving, acquisition, storage, and analysis subsystems, including but not limited to single-component or multi-component electric and magnetic field sensors and data acquisition units; Transmitting Loop Support Structure: The device that mechanically fixes the transmitting and receiving subsystems, and is not limited to any implementation form such as a frame, splicing, or integral type; Power Module: Used to provide operating power for the transmitting and receiving subsystems; Coordinated Distributed Lift of Multiple UAVs: The system distributes the total weight of the system by distributing multiple UAVs at different support points in space, thereby increasing the overall lift limit. The thrust and flight attitude of the UAVs are kept synchronized through a central system or joint automatic scheduling, achieving stable hovering and flight of the entire system and breaking the technical bottleneck of insufficient lift from a single platform.

[0038] This implementation method enables the following: in complex terrains such as plateaus, deserts, and jungles, the distributed UAV structure effectively enhances the carrying capacity and operational flexibility of the airborne transient electromagnetic system, ensuring lift safety and engineering economy under the requirements of deep-sea and high-magnetic-moment detection; the various functional units of the system can be flexibly assembled and scheduled, and the overall system uptime and maintenance costs are reduced, thereby significantly expanding the application boundaries and engineering applicability of traditional airborne transient electromagnetic technology.

[0039] Specifically, the power module providing power to the transmission subsystem can be installed separately or integrated into the transmission subsystem. The receiver is used to record the observation signals output by the sensors. The sensors are used to observe the electric or magnetic field response of the ground. One implementation of the aforementioned transmission loop support structure can preferably be made of insulated tubing. Different polygonal structures can be obtained by connecting straight and bent pipe fittings. The transmission loop is laid inside the tubing or wrapped around the tubing wall, which can meet the needs of different application scenarios. Among them, the common polygonal structures are regular 12-sided and regular 16-sided polygons. The assembled transmission loop support structure is carried by multiple UAVs. Multiple lifting hooks are evenly distributed on the transmission loop support structure as connecting parts for carrying. The lift required to lift the transmission loop support structure is distributed on the multiple UAVs carrying it by cable connection. During use, depending on the application scenario, the aforementioned sensors can be selected as single-component sensors or multi-component sensors for field exploration.

[0040] Example 2: In one preferred embodiment of this invention, the aerospace transient electromagnetic system, to ensure a high degree of modularity and reconfigurability of its transmit loop support structure, is assembled from multiple tubular components. Each component can be selected from materials such as fiberglass tubing, carbon fiber tubing, and insulated metal tubing, depending on its strength. The transmit loop support structure consists of two basic types of tubing: straight tubing and angle tubing. The components are securely connected using specialized detachable connectors (such as plug-in locks, bolts, and elastic pins) to ensure rapid assembly and disassembly at the work site.

[0041] Straight tubes are typically used as side components of the transmitter loop support structure, and different lengths of straight tubes can be used to adjust the overall size of the transmitter loop support structure. Corner tubes serve as corner nodes; by selecting corner tubes with different bending angles, they can be assembled to form polygons or other geometric structures with different numbers of sides. For example, according to the actual detection area requirements and the required transmission magnetic moment, they can be assembled into regular 12-sided, regular 16-sided, regular polygonal, or irregular polygonal structures to meet customized requirements for volume and magnetic moment.

[0042] When it is necessary to increase the area of ​​the transmission loop to accommodate deep-sea exploration, a longer straight pipe is selected to expand the load-bearing structure of the transmission loop. When encountering terrain constraints or small-scale exploration missions, a shorter straight pipe and a smaller bend are selected to flexibly build a compact or irregular structure. All pipe connection points are reserved with UAV mounting interfaces, so that each pipe can be adjusted according to the number of UAVs and the load distribution.

[0043] The disassembly and assembly process is completed by ground personnel or ground-based automated mechanical assistants. All connectors are designed for easy disassembly and high reliability, ensuring quick assembly and disassembly, and facilitating transportation and maintenance. After the pipes are assembled, a complete lift-type launch line load-bearing structure suitable for different exploration scenarios can be formed by threading cables and laying launch loops.

[0044] In practical applications, the system controller can automatically or semi-automatically plan the area, shape, and dimensions of each component of the transmitter loop support structure based on the mission parameters of the current exploration area (such as expected exploration depth, area area, terrain complexity, etc.). Through modular splicing and detachable connection of components, the system enables rapid "parameterized reconfiguration" of the airborne transient electromagnetic system under different operational tasks, significantly improving the system's adaptability and mission flexibility.

[0045] The technical effects of this implementation method are as follows: the transmit loop bearing structure of the present invention can be detachably spliced ​​through pipe fittings, which can significantly improve the structural customization capability and on-site assembly efficiency of the aviation transient electromagnetic system in various complex application scenarios, maximize the balance of operation depth, range and mobility, greatly reduce the difficulty of transportation and maintenance, and achieve efficient equipment deployment and improved utilization.

[0046] Preferably, in one of the preferred technical solutions of this embodiment, the plurality of UAVs, in addition to including a second type of UAV for carrying the transmission loop support structure, further include: a first type of UAV for carrying the transmitter and power module, and a third type of UAV for carrying the receiving subsystem; the aerospace transient electromagnetic system is used to supply power to the transmitting subsystem and the receiving subsystem respectively; the number of the second type of UAVs is multiple.

[0047] Preferably, in one of the preferred technical solutions of this embodiment, the first type of UAV is further equipped with a power module for supplying power to the transmitter.

[0048] Preferably, in one of the preferred technical solutions of this embodiment, the plurality of UAVs maintain a predetermined formation configuration when carrying the transmission loop.

[0049] Preferably, such as Figure 2As shown, in one preferred embodiment, the first type of UAV (AP) is electrically connected to the transmit line via a power supply cable GP. The power supply cable is equipped with a cable disconnection device CP, which is configured to automatically disconnect the electrical and mechanical connections when the tensile force it bears exceeds a preset threshold. Specifically, in one implementation, the power supply cable GP is a composite transmit cable. This composite transmit cable is introduced into the transient electromagnetic interface of the type 1 UAV in the form of a composite cable, but it is not directly connected to the cable inside the transmit line carrying structure. Instead, it is connected to a "cable disconnection device," as illustrated in the schematic diagram below. Figure 2 As shown, both the transmitter loop inlet (RP) and transmitter loop outlet (KP) are electrically connected to the power supply cable (GP) via cable disconnection devices. The cable disconnection device primarily consists of a tensile connector; when the tension at both ends of this connector reaches a certain level, the connector will be pulled open. This design aims to prevent damage to the first-class UAV caused by ground obstacles preventing the transmitter loop structure from advancing during flight. A housing is designed for this connector, and a non-load-bearing cable (LP, with a tensile strength less than the connector's breaking tensile force) is used to connect it to the transmitter loop support structure, thus constraining the cable disconnection device's swaying during flight to a certain extent.

[0050] Preferably, in one of the preferred technical solutions of this embodiment, the multiple UAVs are coordinated and controlled by a formation flight control system to actively maintain the attitude stability of the transmission loop support structure and / or the stability of the positional relationship between the sensor and the transmission loop during flight.

[0051] Example 3: This invention also provides an airborne transient electromagnetic method, suitable for large-scale, efficient geophysical exploration using a distributed unmanned aerial vehicle (UAV) platform. The method mainly consists of the following steps: The first step is to provide and assemble the transmitter loop support structure. Based on the predetermined survey mission parameters (such as target detection depth, transmission magnetic moment, flight area, and specific terrain conditions), suitable modular tubular components are selected on-site and quickly assembled into a transmitter loop support structure that meets the mission requirements. For example, multiple straight and corner tubes can be detachably assembled into a regular polygonal planar structure; the number and length of the sides can be adjusted according to the survey mission. Subsequently, the transmitter loop is fixed to the transmitter loop support structure using cable threading or wrapping methods, ensuring reliable electrical connections and physical support. During transportation, the aforementioned transmitter loop support structure is disassembled into basic straight and corner tubes, and reassembled according to the pre-designed assembly upon arrival at the survey area. After the survey is completed, it will also be disassembled into basic straight and corner tubes and transported by vehicle.

[0052] The second step involves deploying multiple drones and mechanically connecting them to various attachment points within the launch cable support structure via connectors. The number, type, and connection point locations of the drones are determined and configured by a controller (which can be a ground-based main control terminal or a distributed automatic control system for the drone swarm) based on the overall dimensions and weight of the launch cable support structure, as well as the altitude and environmental conditions of the detection site. The drones are connected to different nodes of the structure via elastic cables or vibration-resistant connection devices to achieve uniform lift distribution and active adjustment of the structure's attitude. After issuing a takeoff command, the system controller coordinates the takeoff, hovering, and formation flight of each drone. Each drone uses flight control algorithms to monitor its own position, altitude, and external disturbances in real time, dynamically adjusting its thrust output to ensure the entire launch cable support structure and the launch cable it supports are stably suspended in the operational airspace, meeting the target's flight altitude and attitude requirements.

[0053] The third step involves the system entering the detection operation process. The controller activates the transmitter, emitting excitation electromagnetic pulses (such as...) into the ground through the transmission loop structure. Figure 1 (As shown). The launch timing and excitation waveform parameters can be set by the controller according to mission requirements and adjusted in real time. During synchronization, sensors located at predetermined positions (such as magnetic field or electric field sensors, see reference) Figure 1 The receiving system (installation method) receives the response signal after the formation is excited and transmits it to the receiver for acquisition, recording and preliminary processing via data line or wireless link.

[0054] It needs to be explained, such as Figure 3 As shown, after the transmission loop support structure is assembled and the transmission loop is mounted on it, ground tests on the ground-based GRD will be carried out. Figure 3 The transmitter FS and the power module GL supplying it are represented by a cube. The transmit loop is connected to the transmitter, forming a complete transmit subsystem. The sensor is placed outside the transmit loop, with its center at a distance L from the center of the transmit loop, where L is not less than 10R, and R is the radius of the transmit loop. The sensor is connected to the receiver using a data cable, forming a complete receive subsystem. The transmit subsystem is then activated, outputting a transmit signal according to pre-designed parameters. The receive subsystem 130 receives the response signal. The response signal is analyzed to determine if the system is functioning correctly.

[0055] During the exploration operation, all UAVs continuously cooperated to maintain the aerodynamic stability and spatial geometry of the transmission loop support structure, ensuring the spatial fixation of the relative positions of the transmitting and receiving systems and effectively guaranteeing the data quality and detection accuracy of the observed signals. After the exploration was completed, following the preset recovery procedure, the UAVs were coordinated to slowly descend and safely land the transmission loop and its support structure.

[0056] The technical advantages of this method are as follows: By employing multiple UAVs to collaboratively provide distributed lift, it not only significantly overcomes the payload limitations of a single lift platform and achieves high scalability in system structure and transmission loop specifications, but also ensures the stability and accuracy of the carrying system during exploration operations. Simultaneously, the highly modular and collaborative nature of the method significantly improves the efficiency of cross-regional deployment and mission scheduling of the detection system, providing solid technical support for high-quality airborne transient electromagnetic detection in challenging areas such as plateaus, Gobi deserts, and dense forests.

[0057] Preferably, in one of the preferred technical solutions of this embodiment, the step of collaboratively controlling the multiple drones includes performing terrain-following flight at a speed of less than 25 m / s.

[0058] Preferably, in one of the preferred technical solutions of this embodiment, the method further includes: system reliability testing, which is carried out on the ground; before conducting flight detection, placing the receiving subsystem outside the transmission loop and maintaining the receiving subsystem at the measurement distance required for clear and effective signal reception; starting the transmission subsystem and observing the response signal characteristics collected by the receiving subsystem until it is determined that the receiving subsystem is in normal working condition.

[0059] Preferably, in one of the preferred technical solutions of this embodiment, the method further includes the step of controlling the plurality of UAVs to raise the transmission loop support structure to a height of more than 1,000 meters to collect background field data before or after the detection.

[0060] Example 4: To further illustrate the operational principle of this embodiment using a third type of UAV equipped with a sensor, the accompanying drawings only show the relative position of the transmission loop and the sensor, omitting other components such as the mounting structure, transmission subsystem, and receiver. The actual transmission loop, which can be a regular polygonal loop, is represented by a circular ring shape in the drawings. This embodiment uses a receiving topology structure consisting of at least one set of the aforementioned receiving subsystem to achieve different observation modes. Multiple UAVs maintain a predetermined formation configuration when carrying the receiving topology structure. See also... Figure 4 and Figure 5 As shown: The bold black circle represents the transmit loop, i.e., the transmit loop Tx. Operating Mode 1: Central Loop, where sensor S1 is located at the center of the transmission loop Tx, and the two are concentric. This mode is a reproduction of traditional helicopter-based aerospace transient electromagnetic systems.

[0061] Operating Mode 2: Dipole-Dipole. All other sensors and the transmit loop follow the same dipole-dipole pattern. The sensor and transmit loop are both installed at height h1. The differences are as follows: (1) The sensor is located directly behind the transmission loop at the same height as the transmission loop, i.e., S2 and S3. In general applications, only S2 is needed, but by adding S3, the observation data of both can be used to construct gradient observations along the direction of the survey line.

[0062] (2) The sensor is located directly behind the transmission loop. There is a sensor position above the other sensor, that is, a sensor position S4 is added above S2, so that the vertical gradient observation can be constructed by the observation data of both.

[0063] (3) The sensor is located directly behind the transmission loop. There is a sensor position to the side of the other sensor, that is, the sensor position S5 is added to the horizontal side of S2, so that the horizontal gradient observation can be constructed by the observation data of both.

[0064] (4) The location of the sensor is not limited to directly behind the transmission loop; it can also be placed in any direction around the transmission loop, such as... Figure 4 The location of S6 in the middle. That is, multiple sensors can be deployed in any direction around the transmission loop as needed (but the distance from the center of the sensor to the center of the transmission loop cannot exceed 15 times the radius of the transmission loop) to form a spatial network structure and achieve high-precision resolution of the ground.

[0065] In addition, such as Figure 5 As shown, the axes of the transmitting loop and the sensor coil are both Z-axis. In practice, sensors along the X-axis and Y-axis can also be deployed at different observation locations.

[0066] Therefore, by deploying multiple Type III UAVs equipped with sensors to capture and collect signals at multiple points, the accuracy of the airborne transient electromagnetic system in distinguishing ground information can be greatly improved.

[0067] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. An airborne transient electromagnetic system, comprising: A transmission subsystem, comprising a transmitter and a transmission loop; as well as A receiving subsystem, the receiving subsystem including a receiver and a sensor for sensing electromagnetic response signals; The characteristic feature is that the aerospace transient electromagnetic system further includes: A transmit loop support structure for supporting the transmit loop; and Multiple drones are connected to the transmit loop support structure via connectors and are configured to provide distributed lift in a coordinated manner to the transmit loop support structure, the transmit loop supported thereon, and a receiving topology consisting of at least one set of receiving subsystems.

2. The aerospace transient electromagnetic system according to claim 1, characterized in that, The transmit loop support structure is composed of multiple detachably connected tubular components, so that the size and / or shape of the transmit loop support structure can be adjusted according to the detection requirements.

3. The aerospace transient electromagnetic system according to claim 1, characterized in that, The plurality of UAVs, in addition to a second type of UAV used to carry the transmission loop support structure, also includes a first type of UAV used to carry the transmitter and power module, and a third type of UAV used to carry the receiving subsystem. Multiple units of the second and third types of UAVs are provided.

4. The aerospace transient electromagnetic system according to claim 3, characterized in that, The multiple drones maintain a predetermined formation configuration while carrying the launch return line.

5. The aerospace transient electromagnetic system according to claim 3, characterized in that, The first type of UAV is electrically connected to the transmission return line via a power supply cable. The power supply cable is equipped with a cable disconnection device, which is configured to automatically disconnect the electrical and mechanical connections when the tensile force it bears exceeds a preset threshold.

6. The aerospace transient electromagnetic system according to claim 1, characterized in that, The multiple UAVs are coordinated and controlled by a formation flight control system to actively maintain the attitude stability of the transmission loop support structure and / or the stability of the positional relationship between the sensor and the transmission loop during flight.

7. An airborne transient electromagnetic method, characterized in that, Includes the following steps: Provide a transmit loop support structure to support the transmit loop of an airborne transient electromagnetic system; Multiple drones are connected to the transmitter loop support structure via connectors, and the multiple drones are controlled in a coordinated manner to provide distributed lift for the transmitter loop support structure and the transmitter loop, so as to deploy the transmitter loop in the air; as well as Electromagnetic pulses are emitted through the transmission loop, and electromagnetic response signals are received by sensors in different observation modes.

8. The method according to claim 7, characterized in that, The steps of coordinating the control of the multiple drones include performing terrain-following flight at a speed of less than 25 m / s.

9. The method according to claim 7, characterized in that, The method further includes: system reliability testing, which is conducted on the ground; before conducting flight detection, placing the receiving subsystem outside the transmission loop and maintaining the receiving subsystem at the measurement distance required for clear and effective signal reception; starting the transmission subsystem and observing the response signal characteristics collected by the receiving subsystem until it is determined that the receiving subsystem is in normal working condition.

10. The method according to claim 8, characterized in that, The method also includes the step of controlling the plurality of UAVs to raise the launch return line support structure to a height of more than 1,000 meters to collect background field data before or after the detection.

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