Emergency rescue one-way wireless through-the-earth communication method based on transient detection device

Abstract

The invention discloses an emergency rescue one-way wireless through-the-earth communication method based on a transient detection device. A receiver of the transient detection device is arranged on the ground, and in the 1: 1 receiving and non-receiving time periods, continuous bipolar rectangular pulses with the duty ratio being 1: 1 emitted by an underground signal generator are received. The receiving period and the transmitting period are the same and are even times of the power frequency period, so that underground signals are highlighted through reverse superposition, power frequency noise is weakened, and the signal-to-noise ratio of an emergency rescue channel is improved. By recording the position and the transmitting period of the underground signal generator, the underground personnel can be positioned without encoding and decoding, and the wireless through-the-earth communication system is a wireless through-the-earth communication mode which can be timely deployed on site and nearby in the underground emergency rescue of the mine.

Description

Technical Field

[0001] This invention pertains to low-frequency wireless emergency rescue communication technology, specifically relating to a one-way wireless ground-penetrating communication method for emergency rescue based on a transient detection device. Background Technology

[0002] Conventional underground communication in Chinese mines mainly includes: wired dispatch communication, which forms the core of underground mine communication and plays a vital role in coal production scheduling and command; local wired communication, which utilizes telephone lines, allowing multiple telephones to be connected simultaneously on the same cable for communication between extensions; and wireless communication, which primarily uses inductive communication, powered carrier communication, mobile cellular communication, and short-range wireless communication based on ZigBee / WiFi. All three conventional wired and wireless mine communication methods rely on wired connections to the surface.

[0003] When accidents such as gas explosions, collapses, or flooding occur in mines, conventional communication equipment is disrupted. Rescue teams face situations where the fate and location of trapped personnel are unknown due to the loss of communication between underground and the surface, making effective and timely rescue impossible. Therefore, there is an urgent need for a technology that can directly achieve wireless through-ground communication transmission to transmit underground information to the surface in a timely manner, providing a reliable basis for the design of rescue plans and the implementation of rescue operations.

[0004] Transient electromagnetic detection technology (Phoenix Geophysics, 2007), applied to geological exploration, has unique advantages in wireless ground-penetrating communication. The existing technology "An Electromagnetic Pulse Rescue Communication System and Communication Method" (Wang Yingjie et al., 2025) aims to apply transient detection technology to rescue communication systems, but this technology (1) does not consider power frequency interference and other interference at the rescue site, resulting in a low signal-to-noise ratio and the inability to establish a reliable rescue information channel. (2) As a one-way wireless communication, it does not include location information in the encoding of the underground transmitter, but uses the TDOA (Time Difference of Arrival) method to establish a three-dimensional coordinate equation set of the signal source that needs to be solved by algorithms such as least squares or particle swarm optimization. Not only does it fail to meet the timeliness and simplicity and speed required for rescue, but the TDOA method, which is applicable to ground positioning, also has a large positioning error because it cannot know the accurate underground propagation speed. (3) It only considers the synchronization between receiving arrays and between transmitting arrays, but does not consider the synchronization between receiving and transmitting. (4) The relationship between the underground transmitter encoding frequency and the receiver sampling rate was not considered, and no compensation measures were found for undersampling. Therefore, the accuracy of decoding could not be guaranteed, and the bit error rate could not be effectively controlled.

[0005] In summary, the existing technology has the following shortcomings: insufficient penetration of wireless ground communication during deep-buried rescue, poor anti-interference ability, large positioning error, and the encoding and decoding not only increase the complexity of the communication system, but also fail to consider the distortion caused by the sampling rate required for decoding.

[0006] Referenced files

[0007] Wang Yingjie, Cai Yujia, Lian Jiale. 2025. An electromagnetic pulse rescue communication system and communication method [P]. CN12001708AP Phoenix Geophysics, 2007. System 2000.net User Manual [H]. Phoenix Corporation China Liaison Office Version No.: 200712v.3.2.1. Summary of the Invention

[0008] The purpose of this invention is to provide an emergency one-way wireless ground-penetrating communication method based on a transient detection device, which does not require encoding and decoding, thereby improving the penetration and anti-interference capabilities of wireless ground-penetrating communication and achieving accurate positioning.

[0009] To solve the above technical problems, the specific technical solution adopted by the present invention is as follows.

[0010] An emergency rescue one-way wireless ground-penetrating communication method based on a transient electromagnetic detection device is characterized by placing the receiver of the transient electromagnetic detection device on the ground and placing the signal generator underground and recording the generator's position; the ground receiver intermittently observes twice within each reception period T, with a reception-to-non-reception ratio of 1:1; after the underground signal generator is triggered, it transmits a bipolar continuous rectangular pulse with a duty cycle of 1:1, synchronized with the ground receiver; the reception period of the ground receiver is an even multiple of the power frequency period; then the following steps are performed:

[0011] The ground receiver in step (1) enhances the signal and eliminates power frequency and DC interference through the following inverse superposition formula.

[0012]

[0013] In the formula, V1(t) i ) and V2(t i ) is the receiver using the initial sampling frequency f sample Within a reception period, at each time t in the first and second reception time periods respectively. i Received voltage value; V(t) i ) represents the voltage value after reverse superposition, i = 1, ..., M is the number of voltage value samples; the number of reverse superpositions ranges from 32 to 2048, and is adjusted according to the changes in the signal-to-noise ratio on site;

[0014] Step (2) The maximum transmitting current of the downhole signal generator is taken as the upper limit of the safety allowable downhole. The period of the bipolar pulse of the signal generator is determined and recorded based on the depth of the downhole roadway and working face by the on-site transient electromagnetic detection results: the shallow part corresponds to the high frequency band, and the deep part corresponds to the low frequency band.

[0015] Step (3) After the ground receiver is started, it begins to search for bipolar pulses from the downhole signal generator; when the overlapping part D of the bipolar pulse and the receiving period does not satisfy the following relationship...

[0016]

[0017] If signal aliasing or no signal acquisition occurs, restart the ground receiver;

[0018] Step (4) Once the downhole signal generator is triggered, it continuously transmits bipolar rectangular pulse signals; once the ground receiver is started, if the condition of formula (3) in step three is met, it will continue to receive signals; if the condition of formula (3) in step three is not met, it will continuously restart until the signal is successfully received or the rescue work is completed.

[0019] The number of reverse superposition operations of the ground receiver is 32 to 2048, which is adjusted according to the changes in the signal-to-noise ratio at the construction site.

[0020] If the signal received by the ground receiver is in the same period as the bipolar pulse emitted by the downhole signal generator, it is determined that the signal reception was successful.

[0021] The location of the downhole signal generator is the location of the personnel downhole.

[0022] The general operation and maintenance of the ground receiver shall be carried out in accordance with the instrument manual and transient detection technical procedures; the arrangement, movement and maintenance of the downhole signal generator shall be carried out in accordance with the relevant specifications for downhole low-voltage electrical equipment.

[0023] The ground transient detection device is any one of the following: center loop, overlapping loop, large constant source loop, electric dipole source, and magnetic dipole source.

[0024] Beneficial effects

[0025] Compared with the prior art, the present invention has the following beneficial effects.

[0026] The ground receiver of this invention adopts a reception period that is an even multiple of the power frequency. The downhole signal generator transmits bipolar rectangular pulses with the same period as the receiver to enhance the downhole signal, eliminate power frequency and DC, and establish a reliable emergency rescue channel with a high signal-to-noise ratio.

[0027] The downhole signal generator of this invention uses periodic location markings, solving the problem of inaccurate positioning in the TDOA method and ensuring positioning accuracy. The bipolar pulse signal is visually identified by the receiver without decoding, achieving timeliness in emergency rescue with low complexity and universal accessibility with low cost.

[0028] Transient detection devices are commonly used exploration equipment in major mining areas and geological exploration units. They can be deployed and used on-site and nearby in a timely manner after a mining accident. Attached Figure Description

[0029] Figure 1 Schematic diagram of the receiver and downhole signal generator of the ground transient detection center loop device

[0030] Figure 2 Schematic diagrams of received waveforms, transmitted waveforms, and power frequency and DC waveforms.

[0031] Figure 3 Diagram of air extraction under extreme conditions

[0032] Figure 4 Schematic diagram of the signal from the downhole signal generator received by the ground receiver

[0033] In the figure: 1. Receiver of the ground transient detection center loop device; 2. Downhole signal generator; 3. Received waveform of the ground transient detection center loop device receiver; 4. Bipolar rectangular pulse waveform transmitted by the downhole signal generator; 5. Power frequency waveform; 6. DC waveform; 7. Waveform of the signal received by the downhole signal generator from the ground receiver. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0035] This invention is applicable to situations where a single signal generator is installed 200m downhole, or where multiple signal generators exist but only one is triggered in an emergency. The embodiment uses a Phoenix Geophysics V8 multifunction transmitter with a field power frequency of 50Hz.

[0036] Example 1

[0037] Install a signal generator 100m downhole. For example... Figure 1 As shown, the V8 receiver is placed on the surface, and the downhole signal generator is placed downhole. The ratio of the receiver's observation period to the non-observation period is 1:1, and the downhole signal generator transmits bipolar continuous rectangular pulses with a duty cycle of 1:1. The receiving and transmitting periods are the same and are both even multiples of the 50-cycle power frequency, as shown below. Figure 2 As shown, the signal can be enhanced by formula (1) to cancel out power frequency and DC interference.

[0038] Through on-site transient detection experiments, it was determined that the receive and transmit period T = 40ms is twice the 50Hz power frequency period (at this time...). Figure 2 The T value is 40ms, which meets the requirement of being an even multiple; based on the on-site signal-to-noise ratio, the number of superpositions is determined to be 128. The transmission current of the downhole signal generator is taken as the upper limit of the downhole safety allowance.

[0039] When a mining accident occurs, the underground signal generator is triggered and continuously transmits signals. A receiver is placed on the ground above the underground signal generator to receive the signals. After the ground receiver is activated, it begins searching for the bipolar pulses of the underground signal generator. If no signal is received after a period of time, signal aliasing or uncontrolled mining operations are suspected. Figure 3 This is the extreme case where D=0, or the downhole signal generator is not triggered. In this case, restart the receiver. After restarting, the receiver receives... Figure 4 The waveform shown, with a period of T = 40ms, indicates that the signal was successfully received, the personnel underground were located, and the receiver was turned off.

[0040] Example 2

[0041] Install a signal generator 200m downhole. Figure 1 As shown, the V8 receiver is placed on the surface, and the downhole signal generator is placed downhole. The ratio of the receiver's observation period to the non-observation period is 1:1, and the downhole signal generator transmits bipolar continuous rectangular pulses with a duty cycle of 1:1. The receiving and transmitting periods are the same and are both even multiples of the 50-cycle power frequency, as shown below. Figure 2 As shown, the signal can be enhanced by formula (1) to cancel out power frequency and DC interference.

[0042] Through on-site transient detection experiments, it was determined that the receive and transmit period T = 40ms is twice the 50Hz power frequency period (at this time...). Figure 2 The T value is 40ms, which meets the requirement of being an even multiple; based on the on-site signal-to-noise ratio, the number of superpositions is determined to be 256. The transmission current of the downhole signal generator is taken as the upper limit of the downhole safety allowance.

[0043] When a mining accident occurs, the underground signal generator is triggered and continuously transmits signals. A receiver is placed on the ground above the underground signal generator to receive the signals. After the ground receiver is activated, it begins searching for the bipolar pulses of the underground signal generator. If no signal is received after a period of time, signal aliasing or uncontrolled mining operations are suspected. Figure 3 This is the extreme case where D=0, or the downhole signal generator is not triggered. In this case, restart the receiver. If no signal is received after restarting... Figure 4The waveform with period T = 40ms shown indicates that the downhole signal generator has not been triggered. It is determined whether the condition of formula (3) is met, and then it is decided whether the receiver should continue to receive or keep restarting until the rescue ends.

[0044] Example 3

[0045] A signal generator is installed 400 meters down the well. For example... Figure 1 As shown, the V8 receiver is placed on the surface, and the downhole signal generator is placed downhole. The ratio of the receiver's observation period to the non-observation period is 1:1, and the downhole signal generator transmits bipolar continuous rectangular pulses with a duty cycle of 1:1. The receiving and transmitting periods are the same and are both even multiples of the 50-cycle power frequency, as shown below. Figure 2 As shown, the signal can be enhanced by formula (1) to cancel out power frequency and DC interference.

[0046] Through on-site transient detection experiments, it was determined that the receive and transmit period T = 80ms is 4 times the 50Hz power frequency period (at this time...). Figure 2 The T value is 80ms, which meets the requirement of being an even multiple; based on the on-site signal-to-noise ratio, the number of superpositions is determined to be 512. The transmission current of the downhole signal generator is taken as the upper limit of the downhole safety allowance.

[0047] When a mining accident occurs, the underground signal generator is triggered and continuously transmits signals. A receiver is placed on the ground above the underground signal generator to receive the signals. After the ground receiver is activated, it begins searching for the bipolar pulses of the underground signal generator. If no signal is received after a period of time, signal aliasing or uncontrolled mining operations are suspected. Figure 3 This is the extreme case where D=0, or the downhole signal generator is not triggered. In this case, restart the receiver. If no signal is received after restarting, [further action will be taken]. Figure 4 The waveform shown has a period of T = 80ms, indicating that the downhole signal generator was not triggered, thus putting the receiver in a state of continuous reception and constant restarting. When it receives a signal like... Figure 4 The waveform shown, with a period of T = 80ms, indicates that the signal was successfully received, the personnel underground were located, and the receiver was turned off.

[0048] The above embodiments of the present invention only illustrate the use of the Phoenix Geophysics V8 instrument from Canada. Other transient electromagnetic instruments, such as the ProTEM from Geonics of Canada and the GDP-32 from Zonge of the United States, can obtain the same one-way communication function for emergency rescue according to the methods or principles of the present invention.

[0049] The above embodiments are only used to illustrate the design concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made based on the principles and design ideas disclosed in the present invention are within the protection scope of the present invention.

Claims

1. A one-way wireless through-the-earth communication method for emergency rescue based on a transient detection device, characterized in that, The receiver of the transient electromagnetic detection device is placed on the ground, and the signal generator is placed underground and the position of the generator is recorded; The ground receiver observes twice in each receiving period T, and the ratio of receiving and non-receiving period is 1:1; after the underground signal generator is triggered, it transmits a bipolar continuous rectangular pulse with the same cycle duty ratio of 1:1 as the ground receiver; the receiving period of the ground receiver is an even multiple of the power frequency period; then the following steps are performed: Step one, the ground receiver enhances the signal and eliminates power frequency and direct current interference through the following reverse superposition formula In the formula, V1(t) i ) and V2(t i ) is the receiver using the initial sampling frequency f sample Within a reception period, at each time t in the first and second reception time periods respectively. i Received voltage value; V(t) i ) represents the voltage value after reverse superposition, and i = 1, ..., M represents the number of voltage value samples; Step two, the maximum transmission current of the underground signal generator is the upper limit of the safety allowance underground, and the period of the bipolar pulse of the signal generator is determined according to the depth of the underground roadway and working face through the on-site transient electromagnetic detection results and is recorded: shallow part corresponds to short period bipolar pulse, deep part corresponds to long period bipolar pulse; Step three, after the ground receiver is started, it begins to search for the bipolar pulse of the underground signal generator; when the coincident part D of the bipolar pulse and the receiving period does not satisfy the following relationship It indicates that signal aliasing or empty mining occurs, and the ground receiver is restarted; Step four, after the underground signal generator is triggered, it continuously transmits the bipolar rectangular pulse signal; after the ground receiver is started, if the formula (3) condition in step three is met, continuous reception is performed; if the formula (3) condition in step three is not met, the ground receiver is restarted until the signal reception is successful or the rescue work is completed.

2. The one-way wireless through-the-earth communication method for emergency rescue based on the transient detection device according to claim 1, characterized in that: The number of reverse superposition of the ground receiver is 32-2048 times, which is adjusted according to the signal-to-noise ratio change at the construction site.

3. The one-way wireless through-the-earth communication method for emergency rescue based on transient detection device according to claim 1, characterized in that: If the signal received by the ground receiver is the same as the bipolar pulse transmitted by the underground signal generator, it is judged that the signal reception is successful.

4. The emergency rescue one-way wireless through-the-earth communication method based on a transient detection device according to claim 1, characterized in that: The position of the underground signal generator is the position of the underground personnel.

5. The emergency rescue one-way wireless through-the-earth communication method based on a transient detection device according to claim 1, characterized in that: The general operation and maintenance of the ground receiver is performed according to the instrument instruction manual and the transient detection technical procedures; the arrangement, movement and maintenance of the underground signal generator are performed according to the relevant specifications of the underground weak current equipment.

6. The emergency rescue one-way wireless through-the-earth communication method based on a transient detection device according to claim 1, characterized in that: The ground transient detection device is any one of the following devices: central loop, overlapping loop, large source loop, electric dipole source and magnetic dipole source.

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