A multi-source ground-air electromagnetic detection transmission regulation method and system

Abstract

The application belongs to the technical field of ground-air electromagnetic detection, and particularly relates to a multi-source ground-air electromagnetic detection emission regulation method and system. A common reference current value is set according to detection requirements, and a command of the common reference current value is transmitted to each emission source. Each emission source synchronously emits current according to the common reference current value. The emission current of each emission source is synchronously collected, and the collected emission current and the emission source belonging to the emission current are paired and marked. The current amplitude deviation of the emission current of each emission source and the common reference current value at the same sampling time point is calculated, a control signal is output to the emission source according to the current amplitude deviation of the emission current of different emission sources and the common reference current value, and the output voltage of a DC / DC converter is changed by each emission source according to the control signal, so that the actual output emission current of each emission source dynamically approximates the common reference current value, and the superposition effect of the excited electromagnetic field in the multi-source ground-air electromagnetic detection system is improved.

Description

Technical Field

[0001] This application belongs to the field of ground-to-air electromagnetic detection technology, specifically a multi-source ground-to-air electromagnetic detection transmission control method and system. Background Technology

[0002] Mineral resources are an indispensable material basis for human production activities and play an important supporting role in national economic and social development.

[0003] Geophysical exploration methods, as one of the key technologies for green mineral exploration, are an effective way to accurately obtain information on underground structures. Among them, electromagnetic methods, with their keen ability to identify differences in the electrical properties of different rocks and minerals, occupy a dominant position in the exploration of strategic metal minerals.

[0004] Ground-to-air electromagnetic (GTE) employs a ground-based transmission and airborne reception method. Current is transmitted to the underground medium via a grounded conductor or long-circuit line, inducing a secondary field. This secondary field signal is then captured by an aerial drone equipped with a receiving system. By analyzing different locations on the response curve, the underground electrical distribution can be obtained, thus enabling the detection of underground ore bodies. As an emerging technology following ground-based and airborne electromagnetic methods, GTE combines the advantages of both, offering high safety, low cost, large exploration depth, and minimal dependence on surface topography, allowing for rapid exploration of large areas. Based on domestic and international research and applications, GTE has become an important tool in energy and resource exploration.

[0005] However, current ground-to-air electromagnetic detection methods still face certain technical bottlenecks: limited by the emission from a single field source and the payload capacity of unmanned platforms, the excitation energy is often dispersed, making it difficult to further improve sensor sensitivity. Especially when the target anomaly is obscured by a high-resistivity layer or other non-conductive covering, the resulting secondary field response is extremely weak, with a low signal-to-noise ratio, making it difficult to identify effective signals and unclearly characterize deep structural information, severely restricting detection depth and resolution. To overcome these problems, academia and engineering have gradually expanded their research focus from single-source field sources to multi-source ground-to-air electromagnetic detection technology. By collaboratively deploying multiple emission sources, the intensity of the primary field excitation is enhanced, improving the detection capability for weak deep anomalies. However, this approach suffers from problems such as inconsistent emission current amplitudes from multiple sources, electromagnetic field interference due to unstable output, reduced signal-to-noise ratio of the detection signal, and blurred responses to deep anomalies. Summary of the Invention

[0006] The first aspect of this application provides a multi-source ground-to-air electromagnetic detection emission control method, which solves the problems in the prior art caused by the inconsistent amplitude of the multi-source emission current and unstable output, resulting in mutual interference of electromagnetic fields, reduced signal-to-noise ratio of the detection signal, and blurred response to deep anomalies.

[0007] The second aspect of this application provides a multi-source ground-to-air electromagnetic detection and control system.

[0008] A multi-source ground-to-air electromagnetic detection transmission control method according to the first aspect of this application includes:

[0009] A common reference current value is set according to the detection requirements, and the instruction for the common reference current value is transmitted to each transmitter.

[0010] Each transmitter synchronously transmits current based on a common reference current value;

[0011] The emission current of each emission source is collected synchronously, and the collected emission current is paired and marked with the emission source to which it belongs;

[0012] Calculate the current amplitude deviation between the emission current of each transmitter and the common reference current value at the same sampling time point, and output control signals to the transmitter based on the current amplitude deviation between the emission current of different transmitters and the common reference current value;

[0013] Each transmitter changes the output voltage of its DC / DC converter according to the control signal, so that the actual output current of each transmitter dynamically approaches the common reference current value.

[0014] Furthermore, the emission current of each transmitter is collected synchronously, including: triggering the acquisition when the rising edge of the clock signal arrives, and completing the sampling within the high-level duration time interval.

[0015] Furthermore, the control signal is a drive signal with different duty cycles generated according to the magnitude of the current amplitude deviation.

[0016] Furthermore, the common reference current value is dynamically adjusted according to the actual detection mission type, specifically including: in time domain mode, a high peak current is used; in frequency domain mode, a continuous and stable current is used.

[0017] Furthermore, based on the magnitude of the current amplitude deviation, drive signals with different duty cycles are generated, including:

[0018] The current amplitude deviation is normalized to obtain the normalized current amplitude deviation;

[0019] A modulation signal is generated by combining PI control with the per-unit current amplitude deviation:

[0020] m=1,2,...n, where For different emission sources, the first Modulated signal at each emission current sampling time point These are the scaling factors corresponding to different emission sources. For different emission sources, the integral coefficients are... The first corresponding to different emission sources The per-unit current deviation at each emission current sampling time point, where m refers to the label of each emission source and n represents the total number of emission sources;

[0021] Based on the modulation signal, a set of independent PWM signals are generated, and the duty cycle of the PWM signals is: , Duty cycle, It is a modulated signal;

[0022] The duty cycle of the drive waveform of the power switching transistor in the driver of each DC / DC converter is adjusted according to the PWM signal.

[0023] A multi-source ground-to-air electromagnetic detection and transmission control system according to the second aspect of this application includes:

[0024] The main controller is used to set the common reference current value according to the detection requirements, and transmit the instruction of the common reference current value to each transmitter. Each transmitter then transmits current synchronously according to the common reference current value.

[0025] It is also used to pair and mark the collected transmission current with the transmission source to which it belongs. The collected transmission current is the transmission current collected by the current sensing unit of each transmission source after waiting for the synchronization clock signal output by the clock synchronization module.

[0026] It is also used to calculate the current amplitude deviation between the emission current of each transmitter and the common reference current value at the same sampling time point, and to output control signals to the transmitter based on the current amplitude deviation between the emission current of different transmitters and the common reference current value.

[0027] Each transmitter controller receives the control signal from the main controller and changes the output voltage of the DC / DC converter according to the control signal, so that the actual output transmission current of each transmitter dynamically approaches the common reference current value.

[0028] Furthermore, the main controller generates drive signals with different duty cycles based on the magnitude of the current amplitude deviation.

[0029] Furthermore, the main controller dynamically adjusts the common reference current value according to the actual detection task type, specifically including: using a high peak current in time domain mode and using a continuous stable current in frequency domain mode.

[0030] Furthermore, the main controller generates drive signals with different duty cycles based on the magnitude of the current amplitude deviation, including:

[0031] The current amplitude deviation is normalized to obtain the normalized current amplitude deviation;

[0032] A modulation signal is generated by combining PI control with the per-unit current amplitude deviation:

[0033] m=1,2,...n, where For different emission sources, the first Modulated signal at each emission current sampling time point These are the scaling factors corresponding to different emission sources. For different emission sources, the integral coefficients are... The first corresponding to different emission sources The per-unit current deviation at each emission current sampling time point, where m refers to the label of each emission source and n represents the total number of emission sources;

[0034] Based on the modulation signal, a set of independent PWM signals are generated, and the duty cycle of the PWM signals is: , Duty cycle, It is a modulated signal.

[0035] Furthermore, the main controller sends independent PWM signals to the corresponding transmitter controllers according to the pairing mark, and adjusts the duty cycle of the drive waveform of the power switch in the DC / DC converter driver according to the PWM signal.

[0036] Compared with the prior art, the advantages of this application are as follows:

[0037] This application can respond in real time to current deviations caused by differences in loop impedance, changes in ambient temperature, and differences in device parameters, and dynamically adjust the power supply voltage of each loop transmitting system. By controlling the output voltage of the DC / DC converter, the problem of asynchronous amplitude of multi-source transmitting currents is solved, which is beneficial to improving the superposition effect of electromagnetic fields in the air-to-ground electromagnetic detection system and helps in the extraction and identification of weak signals in deep environments. Attached Figure Description

[0038] Figure 1 A structural block diagram of a multi-source ground-to-air electromagnetic detection and control system provided in this application embodiment;

[0039] Figure 2 A flowchart of a multi-source ground-to-air electromagnetic detection transmission control method provided in this application embodiment. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0041] Multi-source ground-to-air electromagnetic detection (GMT) uses multiple transmitters deployed on the ground to power a transmission system, emitting a primary pulse electromagnetic field into the ground. A receiving system on a UAV then observes the induced secondary field, enabling rapid and precise detection of underground structures. However, differences in internal instrument parameters and circuit impedance often lead to current mismatch between transmitters. This mismatch refers to voltage drop losses caused by the impedance of the transmitting leads, resulting in the injected current into the ground load not reaching the target value. Furthermore, due to varying circuit impedances, the current amplitudes are uneven; even with the same transmitter voltage, differences in circuit impedance can cause variations in the transmitted current amplitude. Besides voltage drop losses from the transmitting leads, mutual resistance between transmitters in multi-source GMT also contributes to current deviations. Since the magnetic field signal strength received by the UAV is proportional to the current amplitude, any change in current will lead to measurement errors, thus affecting the accuracy of interpretation.

[0042] Since signal strength is proportional to current amplitude, different amplitudes result in different excited signal strengths, making proper superposition impossible. This degrades the electromagnetic field superposition effect of multi-source transmission systems, leading to insufficient primary field strength and stability, severely limiting deep-ground detection effectiveness. Currently, the transmitters in air-to-ground electromagnetic detection systems are typically powered by DC / DC rectified power supplies. Therefore, to address the above problems, this application provides a multi-source air-to-ground electromagnetic detection transmission control method and system to ensure that the multi-source transmission current remains highly consistent during detection, improving the quality and reliability of the detection data.

[0043] The core idea of ​​this application embodiment is to ensure the synchronization of the amplitude of the multi-source transmission current by controlling the output voltage of the DC / DC converter used to power the transmission system. Specifically, this includes: synchronously acquiring the current of each transmission source, having the main controller calculate the current deviation and output a set of independent PWM signals, and having the driver generate a drive signal based on the PWM signals to change the output voltage of the DC / DC converter, thereby making the actual output current of each transmission source dynamically approach and stabilize at the set transmission current value.

[0044] See Figure 1 As shown in the figure, a multi-source ground-to-air electromagnetic detection and transmission control system according to an embodiment of this application includes: a main controller, used to set a common reference current value according to the detection requirements, transmit the instruction of the common reference current value to each transmitting source, and each transmitting source synchronously transmits current according to the common reference current value;

[0045] It is also used to pair and mark the collected transmission current with the transmission source to which it belongs. The collected transmission current is the transmission current collected by the current sensing unit of each transmission source after waiting for the synchronization clock signal output by the clock synchronization module.

[0046] It is also used to calculate the current amplitude deviation between the emission current of each transmitter and the common reference current value at the same sampling time point, and to output control signals to the transmitter based on the current amplitude deviation between the emission current of different transmitters and the common reference current value.

[0047] Each transmitter controller receives the control signal from the main controller and changes the output voltage of the DC / DC converter according to the control signal, so that the actual output transmission current of each transmitter dynamically approaches the common reference current value.

[0048] Each transmitter is located in a different geographical location and is powered by an independent transmitter system. Each transmitter controller communicates with the main controller and is synchronized via a clock. The main controller can control multiple transmitters.

[0049] The main controller sets a common reference current value; the current sensing unit in each transmitter collects the actual transmission current of each transmitter in real time and synchronously; each transmitter and the main controller establish a communication protocol to determine the transmitter corresponding to each data. The main controller pairs and marks the returned transmission current with the transmitter, thereby distinguishing the transmission current of different transmitters.

[0050] The main controller compares each actual current value with the common reference current and calculates the current amplitude deviation. Based on the multiple current amplitude deviations, it generates a set of independent PWM signals, which are used to control their respective transmitters. The PWM signals are transmitted to each transmitter controller and output to the driver of the DC / DC converter of each transmitter. The driver generates a drive signal based on the received PWM signal, and then adjusts the excitation voltage applied to each transmitter to compensate for the voltage drop loss caused by the difference in loop impedance.

[0051] This application sets up multiple current sensing units, each corresponding to a transmitter, for high-precision, low-latency acquisition of actual current values; multiple drivers, whose input terminals receive PWM signals from the main controller received from the transmitter controller, and the drivers connected to the transmitter controller are connected to the control terminals of the power switching transistors of the DC / DC converter for driving signals, thereby adjusting the output voltage of each DC / DC converter.

[0052] Multiple DC / DC converters are distributed in different transmitters. Their input terminals are connected to the power supply battery pack, their output terminals are connected to each transmitter, and their drive terminals receive drive signals from the driver.

[0053] Multiple power supply battery packs have their outputs connected to each DC / DC converter to power each DC / DC converter.

[0054] The clock synchronization module uses a pulse generator inside the transmitter to generate the clock signal. The clock signals of each transmitter controller are identical. The rising edge, period, and high-level duration of the clock signal are highly consistent with the current pulses emitted by the transmitter. This module provides a synchronous clock signal for each current sensing unit. Whenever the rising edge of the clock signal arrives, it triggers the acquisition. The sampling is completed within the high-level duration time interval, while ensuring that the current data acquisition time of each transmitter is strictly consistent.

[0055] In one embodiment, the emission current of each transmitter is acquired by a current sensing unit. The current sensing unit is a Hall effect-based current sensor with a measurement bandwidth of 100kHz or higher. The emission current acquired by the current sensing unit is transmitted to the main controller through communication between the transmitter controller and the main controller.

[0056] In one embodiment, the main controller waits for a synchronization clock signal output by the clock synchronization module. Upon receiving the synchronization clock signal, it begins to receive the emission current of each transmitter collected by each current sensing unit in real time. The main controller compares the collected emission current of each transmitter with a preset common reference current value and calculates the current amplitude deviation. Based on the current amplitude deviation, the main controller generates a set of independent PWM signals and outputs them to the transmitter controller. The transmitter controller, through a driver, adjusts the drive signal output to the DC / DC converter according to each PWM signal. The duty cycle of each PWM signal varies due to the different current amplitude deviations. Based on the drive waveform output by the driver, each DC / DC converter changes its output voltage, thereby changing the emission current of each transmitter. Through dynamic adjustment, the system gradually brings the emission current of each transmitter closer to the set emission current amplitude.

[0057] In one embodiment, the main controller generates drive signals with different duty cycles based on the magnitude of the current amplitude deviation, including:

[0058] The current amplitude deviation is normalized to obtain the normalized current amplitude deviation;

[0059] A modulation signal is generated by combining PI control with the per-unit current amplitude deviation:

[0060] m=1,2,...n, where For different emission sources, the first Modulated signal at each emission current sampling time point These are the scaling factors corresponding to different emission sources. For different emission sources, the integral coefficients are... The per-unit current deviation at the k-th emission current sampling time point corresponding to different emission sources, where m refers to the label of each emission source and n is the total number of emission sources;

[0061] Based on the modulation signal, a set of independent PWM signals are generated, and the duty cycle of the PWM signals is: , Duty cycle, It is a modulated signal.

[0062] Furthermore, the main controller sends independent PWM signals to the corresponding transmitter controllers according to the pairing mark, and adjusts the duty cycle of the drive waveform of the medium power switching transistor in the DC / DC converter according to the PWM signal.

[0063] On the other hand, see Figure 2 The method for controlling the transmission of multi-source ground-to-air electromagnetic detection, as shown, includes:

[0064] A common reference current value is set according to the detection requirements, and the instruction for the common reference current value is transmitted to each transmitter.

[0065] Each transmitter synchronously transmits current based on a common reference current value;

[0066] The emission current of each emission source is collected synchronously, and the collected emission current is paired and marked with the emission source to which it belongs;

[0067] Calculate the current amplitude deviation between the emission current of each transmitter and the common reference current value at the same sampling time point, and output control signals to the transmitter based on the current amplitude deviation between the emission current of different transmitters and the common reference current value;

[0068] Each transmitter changes the output voltage of its DC / DC converter according to the control signal, so that the actual output current of each transmitter dynamically approaches the common reference current value.

[0069] Specifically, the excitation current required for the detection mission is set, and this excitation current is used as a common reference current value for multiple transmitters. This includes: obtaining the detection depth required by the detection mission; determining the output power of the transmitter based on the detection depth and the conditions of the detection area; and determining the excitation current based on the output power and the transmitter circuit parameters.

[0070] The common reference current value is dynamically adjusted according to the actual detection mission type. Specifically, in the time domain mode, a high peak current is used to enhance the secondary field response of the excitation; in the frequency domain mode, a continuous and stable current is used to ensure the consistency of the signal phase.

[0071] By placing current sensing units near the grounding electrodes of each transmitter, the current emitted by each transmitter to the ground load is collected in real time. The main controller receives the emission current pulses of each transmitter collected by the current sensing units through the time synchronization module. The main controller can dynamically adjust the required excitation current by a small amount according to the peak value of the collected current pulses.

[0072] In one embodiment, the generation of drive signals with different duty cycles based on the magnitude of the current amplitude deviation includes: normalizing the current amplitude deviation to obtain a normalized current amplitude deviation; the formula is as follows:

[0073] ,in The deviation in current amplitude corresponds to different emission sources. It is the common reference current value.

[0074] A modulation signal is generated by combining PI control with the per-unit current amplitude deviation:

[0075] m=1,2,...n, where For different emission sources, the first Modulated signal at each emission current sampling time point These are the scaling factors corresponding to different emission sources. For different emission sources, the integral coefficients are... The per-unit current deviation at the k-th emission current sampling time point corresponding to different emission sources, where m refers to the label of each emission source and n is the total number of emission sources;

[0076] Based on the modulation signal, a set of independent PWM signals are generated, and the duty cycle of the PWM signals is: , Duty cycle, It is a modulated signal;

[0077] Each of the PWM signals is output to the driver of each DC / DC converter. The driver generates a corresponding drive signal for the power switch based on the received PWM signal, and then adjusts the excitation voltage applied to each transmitting circuit to compensate for the voltage drop loss caused by the difference in circuit impedance. The excitation voltage calculation formula is as follows:

[0078] ,in, The output voltage of the DC / DC converter. The input voltage of the DC / DC converter. The duty cycle of the drive signal is used. This embodiment uses two independent boost DC / DC converters, each connected to a different load to simulate different line impedances in real-world applications. The input voltage of each converter is set to 1500V, and the reference current is set to 50A. The output current is compared with the common reference current value, and the current amplitude deviation is calculated. Based on the different current amplitude deviations, drive signals with different duty cycles are output to the drive circuits of each DC / DC converter, thereby controlling the current. The results show that the same current amplitude is achieved after a short time.

[0079] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for controlling the transmission of multi-source ground-to-air electromagnetic detection, characterized in that, include: A common reference current value is set according to the detection requirements, and the instruction for the common reference current value is transmitted to each transmitter. Each transmitter synchronously transmits current based on a common reference current value; The emission current of each emission source is collected synchronously, and the collected emission current is paired and marked with the emission source to which it belongs; Calculate the current amplitude deviation between the emission current of each transmitter and the common reference current value at the same sampling time point, and output control signals to the transmitter based on the current amplitude deviation between the emission current of different transmitters and the common reference current value; Each transmitter changes the output voltage of its DC / DC converter according to the control signal, so that the actual output current of each transmitter dynamically approaches the common reference current value. Based on the magnitude of the current amplitude deviation, different duty cycle drive signals are generated, including: The current amplitude deviation is normalized to obtain the normalized current amplitude deviation; A modulation signal is generated by combining PI control with the per-unit current amplitude deviation: m=1,2,...n, where For different emission sources, the first Modulated signal at each emission current sampling time point These are the scaling factors corresponding to different emission sources. These are the integral coefficients corresponding to different emission sources. The first corresponding to different emission sources The per-unit current deviation at each emission current sampling time point, where m refers to the label of each emission source and n represents the total number of emission sources; Based on the modulation signal, a set of independent PWM signals are generated, and the duty cycle of the PWM signals is: , Duty cycle, It is a modulated signal; The duty cycle of the drive waveform of the power switching transistor in the driver of each DC / DC converter is adjusted according to the PWM signal.

2. The multi-source ground-to-air electromagnetic detection transmission control method according to claim 1, characterized in that, The synchronous acquisition of the emission current of each transmitter includes: triggering acquisition when the rising edge of the clock signal arrives, and completing sampling within the high-level duration time interval.

3. The multi-source ground-to-air electromagnetic detection transmission control method according to claim 1, characterized in that, The control signal is a drive signal with different duty cycles generated based on the magnitude of the current amplitude deviation.

4. The multi-source ground-to-air electromagnetic detection transmission control method according to claim 1, characterized in that, The common reference current value is dynamically adjusted according to the actual detection mission type, specifically: in time domain mode, a high peak current is used; in frequency domain mode, a continuous and stable current is used.

5. A multi-source ground-to-air electromagnetic detection and control system, characterized in that, include: The main controller is used to set the common reference current value according to the detection requirements, and transmit the instruction of the common reference current value to each transmitter. Each transmitter then transmits current synchronously according to the common reference current value. It is also used to pair and mark the collected transmission current with the transmission source to which it belongs. The collected transmission current is the transmission current collected by the current sensing unit of each transmission source after waiting for the synchronization clock signal output by the clock synchronization module. It is also used to calculate the current amplitude deviation between the emission current of each transmitter and the common reference current value at the same sampling time point, and to output control signals to the transmitter based on the current amplitude deviation between the emission current of different transmitters and the common reference current value. Each transmitter controller receives the control signal from the main controller and changes the output voltage of the DC / DC converter according to the control signal, so that the actual output transmission current of each transmitter dynamically approaches the common reference current value. The main controller generates drive signals with different duty cycles based on the magnitude of the current amplitude deviation, including: The current amplitude deviation is normalized to obtain the normalized current amplitude deviation; A modulation signal is generated by combining PI control with the per-unit current amplitude deviation: m=1,2,...n, where For different emission sources, the first Modulated signal at each emission current sampling time point These are the scaling factors corresponding to different emission sources. These are the integral coefficients corresponding to different emission sources. The first corresponding to different emission sources The per-unit current deviation at each emission current sampling time point, where m refers to the label of each emission source and n represents the total number of emission sources; Based on the modulation signal, a set of independent PWM signals are generated, and the duty cycle of the PWM signals is: , Duty cycle, It is a modulated signal.

6. A multi-source ground-to-air electromagnetic detection and control system according to claim 5, characterized in that, The main controller generates drive signals with different duty cycles based on the magnitude of the current amplitude deviation.

7. A multi-source ground-to-air electromagnetic detection and control system according to claim 5, characterized in that, The main controller dynamically adjusts the common reference current value according to the actual detection task type, specifically including: using a high peak current in time domain mode and a continuous stable current in frequency domain mode.

8. A multi-source ground-to-air electromagnetic detection and control system according to claim 7, characterized in that, The main controller sends independent PWM signals to the corresponding transmitter controllers according to the pairing mark, and adjusts the duty cycle of the drive waveform of the power switching transistor in the DC / DC converter driver according to the PWM signal.

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