Underground operator positioning and communication method and system based on RFID and communication

Abstract

The invention relates to the technical field of mine safety internet of things, in particular to a method and a system for positioning and communicating underground operating personnel based on RFID (Radio Frequency Identification Device) and communication. According to the method, passive RFID tags can be arranged on key nodes of a roadway top plate or a side wall, unique position coordinate data are stored in the passive RFID tags, an anti-explosion terminal worn by an operator obtains the coordinate data by scanning the RFID tags and uploads the coordinate data to a ground monitoring center through a gateway, and the ground monitoring center monitors the position of the operator in real time. A traditional mine positioning communication architecture is subverted through RFID scanning and a LoRa ad hoc network, a trilateral positioning algorithm is combined with Kalman filtering fusion of IMU inertial navigation, the positioning error of an underground key area is compressed, the blind area coverage rate is greatly increased, a ray method electronic fence and continuous position point judgment logic are adopted, the false alarm rate of a dangerous area is reduced, and the safety of a mine is improved. And a passive monitoring system is upgraded to an active protection system, so that a full-chain closed loop in a mine environment is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mine safety Internet of Things, in particular to a positioning and communication method and system for underground workers based on RFID and communication. BACKGROUND

[0002] At present, there are many limitations in the communication means in the coal mine underground. The traditional wired communication system, such as optical fiber communication and industrial Ethernet, can provide high bandwidth and low delay in key applications such as data transmission and video monitoring, but in the mine, the complex geological structure often leads to difficult line laying and high maintenance cost, and is easily affected by the environment, with serious signal attenuation and poor anti-interference ability. The wireless communication scheme based on Bluetooth and WiFi has limited coverage, and in the special environment of narrow and winding roadway structure, complex electromagnetic environment, high concentration of coal dust and potential explosion danger, the signal quality is difficult to guarantee, and it is difficult to meet the communication demand of deep well long distance.

[0003] In addition, the conventional RFID identification scheme is mostly fixed reading, which cannot adapt to the identification demand of personnel movement, especially in the case of mine disaster and other emergencies, the information tracking and communication interruption problem is particularly prominent. Although the UWB (Ultra Wide Band) positioning technology has the advantages of high precision positioning, strong anti-interference ability, strong penetration ability and low power consumption, it is suitable for precise positioning in the special closed area of underground limited operation, and the UWB signal may be disturbed by the complex environment in the underground, such as multipath effect, and its equipment cost is relatively high, which faces certain challenges in large-scale deployment.

[0004] Although ZigBee technology, as a kind of low-power, low-cost and low-rate wireless communication technology, has the characteristics of low power consumption, low cost, large network capacity, short time delay, good security and self-organizing network, it is suitable for monitoring and management of mine internal environment and wireless communication of underground personnel, but its transmission range is usually between 10-30 meters, and the transmission distance is short. For deep well long distance communication, ZigBee technology alone is difficult to meet the demand, and its data transmission rate is low, which is not suitable for some high-speed data transmission application scenarios. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a positioning and communication method and system for underground workers based on RFID and communication, so as to solve the problem that the communication means in the prior art cannot meet the demand when facing the communication working condition in the underground.

[0006] According to the first aspect of the embodiment of the present application, a positioning and communication method for underground workers based on RFID and communication is provided, comprising: Passive RFID tags are placed at key nodes on the tunnel roof or sidewalls, wherein the passive RFID tags store unique location coordinate data; the spacing between the passive RFID tags is dynamically adjusted according to the tunnel topology; The explosion-proof terminal worn by the operator actively scans the RFID tags within a preset distance at a preset time interval; when the explosion-proof terminal recognizes the RFID tag, it obtains the unique location coordinate data stored in the RFID tag and sends the coordinate data to the outside; The target node closest to the explosion-proof terminal receives the coordinate data and verifies the data integrity. If the target node is not directly connected to the gateway, multi-hop routing is initiated. The target node has a built-in routing fault-tolerant algorithm that automatically switches to an alternative path when a node fails. The coordinate data is uploaded to the ground monitoring center via the gateway. The ground monitoring center analyzes the coordinate data and matches it to the underground digital map through the coordinate mapping engine. The digital map renders the personnel location icon in real time. When a person is detected entering the preset electronic fence area, an audible and visual alarm is triggered and a warning message is automatically pushed to the emergency dispatch center. The explosion-proof terminal has a built-in local cache of scanning records within a preset time. After the communication is restored, the explosion-proof terminal will upload all the cached scanning records to the cloud server, and the ground monitoring center will restore the trajectory based on the scanning records.

[0007] Preferably, the spacing of the passive RFID tags is dynamically adjusted according to the lane topology, further comprising: The passive RFID tags are arranged in an equidistant matrix on the tunnel roof and in a staggered pattern on the side walls; The passive RFID tag has a built-in temperature sensor, which automatically activates the high temperature alarm when the ambient temperature is greater than 70°C; The unique location coordinate data stored in the passive RFID tag includes: three-dimensional geographic information of longitude, latitude and altitude depth; The coordinate data is encrypted by SHA-256 before being written, and the explosion-proof terminal verifies the key when reading it, and obtains the coordinate data after the verification is passed; The RFID tag sleep current is ≤0.1μA.

[0008] Preferably, the passive RFID tags are arranged in an equidistant matrix on the tunnel roof and in a staggered pattern on the side walls, including: In straight lane sections, based on the typical reading radius of 10 meters for RFID tags and the signal attenuation model, the maximum spacing between RFID tags is set to ≤50 meters, and the signal overlap area between adjacent RFID tags is set to ≥30%, so that any location is covered by at least one RFID tag. In the turning / fork section, the density is dynamically adjusted based on the turning center angle θ. When θ ≥ 30°, one tag is placed every 10° along the turning arc so that the RFID tag spacing at the inner radius of the turn is ≤ 15 meters. At the fork, six tags are evenly spaced around a circle with a radius of 5 meters, centered at the intersection. When the coal dust concentration is greater than 10 mg / m 3 In certain areas, the spacing is reduced by an additional 20% to offset signal attenuation.

[0009] Preferably, before the explosion-proof terminal sends the coordinate data to the outside, it also includes: The explosion-proof terminal pre-processes the coordinate data and encapsulates the explosion-proof terminal ID, scanning timestamp, and unique location coordinate data stored in the RFID tag into a data packet; The data packet includes a packet header, a payload, and a packet tail; the packet header includes a 4-byte synchronization code, a 2-byte packet length, and a 1-byte protocol version; the payload includes a 16-byte terminal ID, an 8-byte timestamp, a 24-byte tag coordinate, and a 1-byte signal strength RSSI; a 2-byte CRC check code is appended to the packet tail; the total length of the data packet is fixed at 57 bytes; The explosion-proof terminal sends data packets in the 470MHz frequency band and 125kHz bandwidth, and the transmission power is dynamically adjusted to 14dBm~20dBm to adapt to changes in the electromagnetic environment of the tunnel.

[0010] Preferably, if the target node is not directly connected to the gateway, multi-hop routing is initiated, including: The target node dynamically selects the next hop node based on signal strength and link quality; The LoRa target node in the area starts caching, aggregates multiple terminal data packets every 200ms, compresses them into a single aggregate frame and sends them. The compression algorithm uses differential coding to facilitate single identification transmission of multi-hop routing; Improve the routing priority of nodes in the turning / fork area so that the number of hops of the alarm data packet is ≤3 and the transmission delay is <100ms.

[0011] Preferably, when a person is detected entering a preset electronic fence area, an audible and visual alarm is triggered and a warning message is automatically pushed to the emergency dispatch center, including: The electronic fence area includes the gas outburst area and the underground area where the risk factor of the goaf is greater than the preset value; When a person is detected entering the electronic fence area, an audible and visual alarm is triggered and a warning message is automatically sent to the emergency dispatch center; The electronic fence area is defined by the coordinates of the polygon vertices. The ray method is used to determine whether the person's position is within the area. When three consecutive position points enter the fence, a level 1 alarm is triggered. If they do not leave within 5 seconds, it is upgraded to a level 2 alarm. The alarm information includes personnel ID, location coordinates, entry time and recommended evacuation route, and is broadcast to surrounding terminals via the LoRa network.

[0012] Preferably, the explosion-proof terminal has a built-in local cache of scan records within a preset time. After the communication is restored after the interruption, the explosion-proof terminal uploads all the cached scan records to the cloud server, and the ground monitoring center performs trajectory recovery based on the scan records, including: The explosion-proof terminal has a built-in data storage unit; The data storage unit uses a FLASH chip to locally cache the scan records within 72 hours, and the data packets are uploaded to the cloud server via the LoRa network; When communication is interrupted, the explosion-proof terminal continues to store data locally. After the communication connection is restored, the explosion-proof terminal automatically synchronizes all cached scan records to the cloud server; After the monitoring center obtains the synchronized scanning records from the cloud server, it performs trajectory restoration and supports path retrieval by personnel ID and time period. The path accuracy is guaranteed by the RFID deployment density.

[0013] Preferably, the method further comprises: During the communication interruption, the explosion-proof terminal stores the scan records in a compressed format, generates a data block for every 30 records and adds a timestamp signature; After the communication connection is restored, the data blocks are retransmitted in chronological order, and the cloud server uses a sliding window mechanism to verify data continuity; If the cloud server finds a time gap greater than 10 seconds, it retrieves adjacent data based on signal spatial correlation weighted interpolation and completes the trajectory through a collaborative positioning algorithm.

[0014] According to a second aspect of an embodiment of the present invention, a system for positioning and communicating underground workers based on RFID and communication is provided, which is configured to execute any of the above-mentioned methods for positioning and communicating underground workers based on RFID and communication, comprising: The terminal module is worn by personnel and is integrated into an explosion-proof housing, including: RFID active scanning unit, used to detect RFID tags within a radius of 10 meters at 0.5 second intervals, using a carrier frequency of 860-960MHz; The LoRa communication unit is used to encapsulate the terminal ID, coordinate data and timestamp into a 57-byte data packet, supports 470-960MHz adaptive frequency hopping, and has a dynamic transmission power adjustment range of 14-20dBm; Data storage unit, used for local compression storage of 72 hours of scanning records; Power management unit for maintaining standby mode with a sleep current of ≤1.5μA; The underground positioning beacon unit includes a passive RFID tag array that stores encrypted unique location coordinate data. The RFID tags are encapsulated in metal-resistant ceramics and anchored to the roadway roof / sidewall with epoxy resin. They are deployed in a topological manner with spacing of ≤50 meters in straight sections and ≤20 meters in turning / fork sections. Ad hoc network communication module, which builds a Mesh network by LoRa nodes, including: Multi-hop routing engine, used to execute the improved AODVjr protocol and dynamically select paths based on cost; Link fault tolerance unit, used to broadcast detection frames every 30 seconds and automatically switch to the backup path in case of failure to ensure connectivity; Ground monitoring center module, including: A real-time positioning engine that parses coordinate data and maps it to a digital map of the well; The electronic fence alarm unit is used to determine whether people have entered the dangerous area based on the ray method and trigger a multi-level linkage response; The trajectory tracing database is used to store cloud data and synchronize it with local terminal records, supporting collaborative positioning interpolation algorithms to repair trajectory gaps.

[0015] Preferably, the person wears a terminal module, further comprising: Dual-frequency RFID scanning subunit, used to simultaneously support 125kHz-13.56MHz high-frequency data transmission, switching to high-frequency mode in metal-dense areas to improve signal-to-noise ratio; The IMU-assisted positioning subunit integrates inertial sensors and is used to start dead reckoning in turning / fork areas. When the RFID signal is lost, the Kalman filter is used to maintain positioning continuity. The positioning deviation compensation formula is:

[0016] in, v is the terminal motion speed, a is the acceleration, Δt is the signal transmission time from t0 to t1; The emergency broadcast subunit is used to drive the buzzer and red LED to flash after receiving the alarm command issued by the LoRa network to warn people to evacuate.

[0017] The technical solutions provided by the embodiments of the present invention may have the following beneficial effects: RFID scanning and LoRa self-organizing networks subvert the traditional mine positioning and communication architecture. At the positioning level, the terminal actively scans RFID tags within a 10-meter radius at a high frequency of 0.5 seconds. Combined with the three-sided positioning algorithm and the Kalman filter fusion of the IMU inertial navigation, positioning errors in key areas underground are compressed, blind spot coverage is greatly improved, and the problem of signal loss caused by curved tunnels is solved. At the communication level, a mesh network is built based on the improved AODVjr protocol, realizing multi-hop transmission at ultra-long node spacing. In the event of a single point of failure, real-time link detection and path reconfiguration ensure a network connectivity rate of >90%. At the safety and early warning level, the use of ray-based electronic fencing and continuous position point determination logic reduces the false alarm rate in dangerous areas and links the shutdown of mining equipment, upgrading from passive monitoring to an active protection system. This realizes a full-chain closed loop of "centimeter-level positioning, second-level early warning, and anti-destruction communication" in the mine environment, setting a new standard for operational safety under complex geological conditions.

[0018] To address the tracing and battery life bottlenecks in mining disaster scenarios, the terminal has a built-in FLASH chip to locally cache 72 hours of trajectory data, continuously store it during communication interruptions, and fill in trajectory gaps through a collaborative positioning algorithm after the connection is restored. Combined with cloud-based digital maps, millisecond-level path playback is achieved, subverting the dilemma of trajectory loss after traditional systems have been lost. In terms of energy consumption control, the LoRa module's deep sleep current is ≤1.5μA, the RFID tag uses a field-strength triggered wake-up mechanism to achieve zero-power standby, the terminal's dual backup power supply supports ultra-emergency standby, the LoRa module supports 470-960MHz adaptive frequency hopping to avoid interference from mine motors, the tag's metal packaging is resistant to high temperatures of >70°C, and the system seamlessly connects to the mine's three-dimensional platform through the OPC UA standard, reducing deployment costs and building a new paradigm for mining safety with "breakpoint-free tracing, ultra-long battery life, and autonomous control."

[0019] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0021] Figure 1 This is a schematic diagram showing the steps of a method for positioning and communicating with underground workers based on RFID and communication according to an exemplary embodiment; Figure 2 is a schematic diagram of a passive RFID tag deployment process according to an exemplary embodiment; Figure 3 is a structural logic diagram of an underground worker positioning and communication system based on RFID and communication according to an exemplary embodiment; Figure 4 The figure is a schematic diagram showing the architecture of an underground worker positioning and communication system based on RFID and communication according to an exemplary embodiment. DETAILED DESCRIPTION

[0022] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, like numbers in different figures represent like or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0023] In one embodiment, see Figure 1 and Figure 2 , provides a method for positioning and communicating underground workers based on RFID and communication, including: Step S11: Passive RFID tags are placed at key locations on the tunnel roof or sidewalls. These tags store unique location coordinate data. The spacing between these tags is dynamically adjusted based on the tunnel topology. The tags are encapsulated using metal-resistant packaging and secured to pre-buried anchor rods using epoxy resin adhesive.

[0024] It should be noted that the spacing of the passive RFID tags is dynamically adjusted according to the lane topology, and further includes: The passive RFID tags are arranged in an equidistant matrix on the tunnel roof and in a staggered pattern on the side walls. The passive RFID tags have a built-in temperature sensor that automatically activates a high-temperature alarm when the ambient temperature is greater than 70°C. The unique location coordinate data stored in the passive RFID tags includes three-dimensional geographic information: longitude, latitude, and altitude depth. The coordinate data is encrypted using SHA-256 before being written, and the explosion-proof terminal obtains the coordinate data through key verification when reading. The RFID tag's sleep current is ≤0.1μA.

[0025] Step S12: The explosion-proof terminal worn by the operator actively scans the RFID tags within a preset distance at a preset time interval; when the explosion-proof terminal recognizes the RFID tag, it obtains the unique position coordinate data stored in the RFID tag, and sends the coordinate data to the outside.

[0026] It should be noted that the explosion-proof terminal pre-processes the coordinate data and encapsulates the explosion-proof terminal ID, the scanning timestamp and the unique position coordinate data stored in the RFID tag into a data packet.

[0027] The data packet includes a packet header, a payload and a packet trailer; the packet header contains a 4-byte synchronization code, a 2-byte packet length and a 1-byte protocol version; the payload contains a 16-byte terminal ID, an 8-byte timestamp, a 24-byte tag coordinate and a 1-byte signal strength RSSI; a 2-byte CRC check code is attached to the packet trailer; the total length of the data packet is fixed at 57 bytes.

[0028] The explosion-proof terminal sends data packets in the 470MHz frequency band and 125kHz bandwidth, and the transmission power is dynamically adjusted to 14dBm~20dBm to adapt to changes in the electromagnetic environment of the tunnel.

[0029] Step S13: The target node closest to the explosion-proof terminal receives the coordinate data and verifies the data integrity. If the target node is not directly connected to the gateway, multi-hop routing is started. The target node has a built-in routing fault-tolerant algorithm and automatically switches to an alternative path when a node fails.

[0030] If the target node is not directly connected to the gateway, multi-hop routing is initiated, including: The target node dynamically selects the next hop node based on signal strength and link quality; The LoRa target node in the area starts caching, aggregates multiple terminal data packets every 200ms, compresses them into a single aggregate frame and sends them. The compression algorithm uses differential coding to facilitate single identification transmission of multi-hop routing; The routing priority of nodes in turning / fork areas is increased to ensure that the number of hops per alarm packet is ≤3 and the transmission delay is <100ms. RFID scanning and LoRa self-organizing networks are used to subvert the traditional mine positioning and communication architecture. At the positioning level, the terminal actively scans RFID tags within a 10-meter radius at a high frequency of 0.5 seconds. This, combined with a three-sided positioning algorithm and Kalman filtering using IMU inertial navigation, reduces positioning errors in key areas underground, significantly improving blind spot coverage and resolving the problem of signal loss caused by curved tunnels.

[0031] In step S14, the coordinate data is uploaded to the ground monitoring center via the gateway. The ground monitoring center analyzes the coordinate data and matches it to the underground digital map using a coordinate mapping engine. The digital map then renders a real-time icon of the personnel's location. When a person enters the preset electronic fence area, an audible and visual alarm is triggered, and a warning message is automatically sent to the emergency dispatch center. At the communication level, a mesh network is constructed based on the improved AODVjr protocol, enabling multi-hop transmission over extremely long node distances. In the event of a single point of failure, real-time link detection and path reconfiguration ensure a network connectivity rate of >90%.

[0032] Step S15: The explosion-proof terminal has a built-in local cache of scanning records within a preset time (72 hours). After the communication is restored, the explosion-proof terminal uploads all the cached scanning records to the cloud server, and the ground monitoring center restores the trajectory based on the scanning records.

[0033] The explosion-proof terminal has a built-in data storage unit; this data storage unit uses a FLASH chip to locally cache scan records for the past 72 hours, while simultaneously uploading the data to a cloud server via the LoRa network. When communications are interrupted, the explosion-proof terminal continues to store data locally. Once communications are restored, it automatically synchronizes all cached scan records to the cloud server. After obtaining synchronized scan records from the cloud server, the monitoring center performs trajectory recovery, supporting path retrieval by person ID and time period. Path accuracy is guaranteed by the density of RFID deployment. The use of ray-based electronic fencing and continuous location point determination logic reduces the false alarm rate in hazardous areas and, in conjunction with the shutdown of mining equipment, upgrades the system from passive monitoring to active protection, achieving a closed-loop "centimeter-level positioning, second-level warning, and anti-destruction communication" in mining environments, setting a new standard for operational safety in complex geological conditions.

[0034] Specifically, in terms of energy consumption control, the deep sleep current of the LoRa module is ≤1.5μA, the RFID tag uses a field strength triggered wake-up mechanism to achieve zero-power standby, the terminal's dual backup power supply supports super emergency standby, the LoRa module supports 470-960MHz adaptive frequency hopping to avoid interference from mine motors, the tag's metal packaging is resistant to high temperatures of >70°C, and the system seamlessly connects to the mine's three-dimensional platform through the OPC UA standard, reducing deployment costs.

[0035] Furthermore, in step S11 of this embodiment, the passive RFID tags are arranged in a matrix with equal spacing on the tunnel roof and in a staggered arrangement on the sidewalls, including: In straight lane sections, based on the typical reading radius of 10 meters for RFID tags and the signal attenuation model, the maximum spacing between RFID tags is set to ≤50 meters, and the signal overlap area between adjacent RFID tags is set to ≥30%, so that any location is covered by at least one RFID tag. In the turning / fork section, the density is dynamically adjusted based on the turning center angle θ. When θ ≥ 30°, one tag is placed every 10° along the turning arc so that the RFID tag spacing at the inner radius of the turn is ≤ 15 meters. At the fork, six tags are evenly spaced around a circle with a radius of 5 meters, centered at the intersection. When the coal dust concentration is greater than 10 mg / m 3 In certain areas, the spacing is reduced by an additional 20% to offset signal attenuation.

[0036] Furthermore, in step S14 of this embodiment, when a person is detected entering a preset electronic fence area, an audible and visual alarm is triggered and a warning message is automatically pushed to the emergency dispatch center, including: The electronic fence area includes the gas outburst area and the underground area where the risk factor of the goaf is greater than the preset value; When a person is detected entering the electronic fence area, an audible and visual alarm is triggered and a warning message is automatically sent to the emergency dispatch center; The electronic fence area is defined by the coordinates of the polygon vertices. The ray method is used to determine whether the person's position is within the area. When three consecutive position points enter the fence, a level 1 alarm is triggered. If they do not leave within 5 seconds, it is upgraded to a level 2 alarm. The alarm information includes personnel ID, location coordinates, entry time and recommended evacuation route, and is broadcast to surrounding terminals via the LoRa network.

[0037] Furthermore, in step S15 of this embodiment, the method further includes: During the communication interruption, the explosion-proof terminal stores the scan records in a compressed format, generates a data block for every 30 records and adds a timestamp signature; After the communication connection is restored, the data blocks are retransmitted in chronological order, and the cloud server uses a sliding window mechanism to verify data continuity; If the cloud server finds a time gap greater than 10 seconds, it retrieves adjacent data based on signal spatial correlation weighted interpolation and completes the trajectory through a collaborative positioning algorithm.

[0038] This technical solution addresses the tracing and endurance bottlenecks in mining disaster scenarios. The terminal has a built-in FLASH chip to locally cache 72 hours of trajectory data, which is continuously stored during communication interruptions. After the connection is restored, the collaborative positioning algorithm is used to fill in the trajectory gaps. Combined with the cloud-based digital map, millisecond-level path playback is achieved, overturning the dilemma of trajectory loss after accidents in traditional systems.

[0039] In another embodiment, see Figure 3 , provides an underground worker positioning and communication system based on RFID and communication, which is used to execute any of the above-mentioned underground worker positioning and communication methods based on RFID and communication, including: The terminal module is worn by personnel and is integrated into an explosion-proof housing, including: RFID active scanning unit, used to detect RFID tags within a radius of 10 meters at 0.5 second intervals, using a carrier frequency of 860-960MHz; The LoRa communication unit is used to encapsulate the terminal ID, coordinate data and timestamp into a 57-byte data packet, supports 470-960MHz adaptive frequency hopping, and has a dynamic transmission power adjustment range of 14-20dBm; Data storage unit for locally compressed storage of 72 hours scan records; Power management unit for maintaining standby at sleep current <= 1.5uA; Downhole positioning beacon unit including passive RFID tag array for storing encrypted unique location coordinate data, RFID tag using metal-resistant ceramic package anchored to roadway roof / sidewall by epoxy resin, deployed under the topology rule of <= 50 meters between straight sections, <= 20 meters between turning / branch sections; Ad-hoc network communication module, LoRa node builds Mesh network, including: Multi-hop routing engine for executing improved AODVjr protocol, dynamically selecting path according to Cost; Link fault tolerance unit for broadcasting probe frames every 30 seconds, automatically switching to standby path in case of failure to ensure connectivity rate; Ground monitoring center module, including: Real-time positioning engine for parsing coordinate data and mapping to downhole digital map; Electronic fence alarm unit for judging personnel entering dangerous area based on ray method and triggering multi-level linkage response; Trajectory tracing database for storing cloud data and synchronizing with terminal local records, supporting collaborative positioning interpolation algorithm to repair trajectory gaps.

[0040] It can be understood that the technical solutions shown in the embodiment overturn the traditional mine positioning communication architecture through RFID scanning and LoRa ad-hoc network, the terminal actively scans RFID tags within a radius of 10 meters at a high frequency of 0.5 seconds, combines three-dimensional positioning algorithm with Kalman filter fusion of IMU inertial navigation, compresses positioning error in key areas underground, greatly improves blind area coverage, solves the problem of signal loss caused by curved roadway, at the communication level, builds Mesh network based on improved AODVjr protocol, realizes multi-hop transmission under super-long node spacing, and guarantees > 90% network connectivity rate through real-time link detection and path recombination in case of single point failure.

[0041] In the embodiment, the personnel wearing terminal module further includes: Dual-frequency RFID scanning subunit for synchronously supporting 125kHz-13.56MHz high-frequency data transmission, switching to high-frequency mode in metal-intensive areas to improve signal-to-noise ratio; IMU auxiliary positioning subunit integrating inertial sensors for starting dead reckoning at turning / branch sections, maintaining positioning continuity through Kalman filtering when RFID signal is lost, and positioning deviation compensation formula being:

[0042] Wherein, vis the terminal motion speed, a is the acceleration, Δt is the signal transmission time from t0 to t1; The emergency broadcast subunit is used to drive the buzzer and red LED to flash after receiving the alarm command issued by the LoRa network to warn people to evacuate.

[0043] It can be understood that the technical solution shown in this embodiment adopts the ray method electronic fence and continuous position point judgment logic at the safety warning level to reduce the false alarm rate in dangerous areas, and to stop the mining equipment in a linked manner, upgrading from passive monitoring to an active protection system, and realizing the full chain closed loop of "centimeter-level positioning-second-level warning-anti-destruction communication" in the mine environment, setting new standards for operational safety under complex geological conditions.

[0044] Reference Figure 4 The figure shows the composition and framework of the underground worker positioning and communication system. The system consists of: Core device: Low-power micro-power wireless communication sensing device for data transmission.

[0045] Positioning tags: Environmental awareness positioning tags and device positioning tags to achieve precise positioning.

[0046] Upper-layer applications: application software and open interfaces that provide user interaction and data access.

[0047] The system framework includes: ‌Perception layer‌: Contains the aforementioned positioning tags and is responsible for data collection.

[0048] ‌Service Layer‌: Manages low-power communication devices and supports automatic networking.

[0049] ‌Network layer‌: Use private network / UDP / TCP protocols to ensure stable data transmission.

[0050] Application layer: Monitoring and display are realized through monitoring host and data receiving terminal.

[0051] This technical solution addresses the tracing and battery life bottlenecks in mining disaster scenarios. The terminal has a built-in FLASH chip to locally cache 72 hours of trajectory data, which is continuously stored during communication interruptions. After the connection is restored, the trajectory gaps are filled through a collaborative positioning algorithm. Combined with cloud-based digital maps, millisecond-level path playback is achieved, subverting the dilemma of trajectory loss after accidents in traditional systems. The tag is resistant to metal packaging and can withstand temperatures above 70°C. The system seamlessly connects to the mining 3D platform through the OPC UA standard, reducing deployment costs and establishing a new paradigm for mining safety with "breakpoint-free tracing, ultra-long battery life, and autonomous control."

[0052] In this embodiment, the entire operation process can be controlled by a computer to provide signal feedback to implement the steps in sequence. These are all conventional knowledge of current automated control and will not be described in detail in this embodiment.

[0053] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0054] It should be noted that, in the description of the present invention, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is at least two.

[0055] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0056] It should be understood that various components of the present invention may be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof may be used: a discrete logic circuit having logic gate circuits for implementing logic functions on data signals, an application-specific integrated circuit having suitable combinational logic gate circuits, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0057] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0058] In addition, each function unit in each embodiment of the present application can be integrated in one processing module, or each unit can be physically present separately, or two or more units can be integrated in one module. The integrated module can be realized in the form of hardware, or in the form of a software function module. When the integrated module is realized in the form of a software function module and sold or used as an independent product, it can also be stored in a computer readable storage medium.

[0059] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0060] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0061] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A method for positioning and communicating underground workers based on RFID and communication, characterized in that: include: Passive RFID tags are placed at key nodes of the tunnel roof or sidewalls, wherein the passive RFID tags store unique location coordinate data; The spacing of the passive RFID tags is dynamically adjusted according to the lane topology; The explosion-proof terminal worn by the operator actively scans the RFID tags within a preset distance at a preset time interval; when the explosion-proof terminal recognizes the RFID tag, it obtains the unique location coordinate data stored in the RFID tag and sends the coordinate data to the outside; The target node closest to the explosion-proof terminal receives the coordinate data and verifies the data integrity. If the target node is not directly connected to the gateway, multi-hop routing is initiated. The target node has a built-in routing fault-tolerant algorithm that automatically switches to an alternative path when a node fails. The coordinate data is uploaded to the ground monitoring center via the gateway. The ground monitoring center analyzes the coordinate data and matches it to the underground digital map through the coordinate mapping engine. The digital map renders the personnel location icon in real time. When a person is detected entering the preset electronic fence area, an audible and visual alarm is triggered and a warning message is automatically pushed to the emergency dispatch center. The explosion-proof terminal has a built-in local cache of scanning records within a preset time. After the communication is restored, the explosion-proof terminal will upload all the cached scanning records to the cloud server, and the ground monitoring center will restore the trajectory based on the scanning records.

2. The method according to claim 1, characterized in that The spacing of the passive RFID tags is dynamically adjusted according to the lane topology, and further includes: The passive RFID tags are arranged in an equidistant matrix on the tunnel roof and in a staggered pattern on the side walls; The passive RFID tag has a built-in temperature sensor, which automatically activates the high temperature alarm when the ambient temperature is greater than 70°C; The unique location coordinate data stored in the passive RFID tag includes: three-dimensional geographic information of longitude, latitude and altitude depth; The coordinate data is encrypted by SHA-256 before being written, and the explosion-proof terminal verifies the key when reading it, and obtains the coordinate data after the verification is passed; The RFID tag sleep current is ≤0.1μA.

3. The method according to claim 2, characterized in that The passive RFID tags are arranged in an equidistant matrix on the tunnel roof and in a staggered pattern on the sidewalls, including: In straight lane sections, based on the typical reading radius of 10 meters for RFID tags and the signal attenuation model, the maximum spacing between RFID tags is set to ≤50 meters, and the signal overlap area between adjacent RFID tags is set to ≥30%, so that any location is covered by at least one RFID tag. In the turning / fork section, the density is dynamically adjusted based on the turning center angle θ. When θ ≥ 30°, one tag is placed every 10° along the turning arc so that the RFID tag spacing at the inner radius of the turn is ≤ 15 meters. At the fork, six tags are evenly spaced around a circle with a radius of 5 meters, centered at the intersection. When the coal dust concentration is greater than 10 mg / m 3 In certain areas, the spacing is reduced by an additional 20% to offset signal attenuation.

4. The method according to claim 3, characterized in that Before the explosion-proof terminal sends coordinate data to the outside, it also includes: The explosion-proof terminal pre-processes the coordinate data and encapsulates the explosion-proof terminal ID, scanning timestamp, and unique location coordinate data stored in the RFID tag into a data packet; The data packet includes a packet header, a payload, and a packet tail; the packet header includes a 4-byte synchronization code, a 2-byte packet length, and a 1-byte protocol version; the payload includes a 16-byte terminal ID, an 8-byte timestamp, a 24-byte tag coordinate, and a 1-byte signal strength RSSI; a 2-byte CRC check code is appended to the packet tail; the total length of the data packet is fixed at 57 bytes; The explosion-proof terminal sends data packets in the 470MHz frequency band and 125kHz bandwidth, and the transmission power is dynamically adjusted to 14dBm~20dBm to adapt to changes in the electromagnetic environment of the tunnel.

5. The method according to claim 4, characterized in that If the target node is not directly connected to the gateway, multi-hop routing is initiated, including: The target node dynamically selects the next hop node based on signal strength and link quality; The LoRa target node in the area starts caching, aggregates multiple terminal data packets every 200ms, compresses them into a single aggregate frame and sends them. The compression algorithm uses differential coding to facilitate single identification transmission of multi-hop routing. Improve the routing priority of nodes in the turning / fork area so that the number of hops of the alarm data packet is ≤3 and the transmission delay is <100ms.

6. The method according to claim 5, characterized in that When a person is detected entering the preset electronic fence area, an audible and visual alarm is triggered and a warning message is automatically sent to the emergency dispatch center, including: The electronic fence area includes the gas outburst area and the underground area where the risk factor of the goaf is greater than the preset value; When a person is detected entering the electronic fence area, an audible and visual alarm is triggered and a warning message is automatically sent to the emergency dispatch center; The electronic fence area is defined by the coordinates of the polygon vertices. The ray method is used to determine whether the person's position is within the area. When three consecutive position points enter the fence, a level 1 alarm is triggered. If they do not leave within 5 seconds, it is upgraded to a level 2 alarm. The alarm information includes personnel ID, location coordinates, entry time and recommended evacuation route, and is broadcast to surrounding terminals via the LoRa network.

7. The method according to claim 6, characterized in that The explosion-proof terminal has a built-in local cache of scan records within a preset time. After the communication is restored, the explosion-proof terminal uploads all cached scan records to the cloud server. The ground monitoring center performs trajectory recovery based on the scan records, including: The explosion-proof terminal has a built-in data storage unit; The data storage unit uses a FLASH chip to locally cache the scan records within 72 hours, and the data packets are uploaded to the cloud server via the LoRa network; When communication is interrupted, the explosion-proof terminal continues to store data locally. After the communication connection is restored, the explosion-proof terminal automatically synchronizes all cached scan records to the cloud server; After the monitoring center obtains the synchronized scanning records from the cloud server, it performs trajectory restoration and supports path retrieval by personnel ID and time period. The path accuracy is guaranteed by the RFID deployment density.

8. The method according to claim 7, characterized in that Also includes: During the communication interruption, the explosion-proof terminal stores the scan records in a compressed format, generates a data block for every 30 records and adds a timestamp signature; After the communication connection is restored, the data blocks are retransmitted in chronological order, and the cloud server uses a sliding window mechanism to verify data continuity; If the cloud server finds a time gap greater than 10 seconds, it retrieves adjacent data based on signal spatial correlation weighted interpolation and completes the trajectory through a collaborative positioning algorithm.

9. A system for positioning and communicating underground workers based on RFID and communication, used to implement the method for positioning and communicating underground workers based on RFID and communication according to any one of claims 1 to 8, characterized in that: include: The terminal module is worn by personnel and is integrated into an explosion-proof housing, including: RFID active scanning unit, used to detect RFID tags within a radius of 10 meters at 0.5 second intervals, using a carrier frequency of 860-960MHz; The LoRa communication unit is used to encapsulate the terminal ID, coordinate data and timestamp into a 57-byte data packet, supports 470-960MHz adaptive frequency hopping, and has a dynamic transmission power adjustment range of 14-20dBm; Data storage unit, used for local compression storage of 72 hours of scanning records; Power management unit for maintaining standby mode with a sleep current of ≤1.5μA; The underground positioning beacon unit includes a passive RFID tag array that stores encrypted unique location coordinate data. The RFID tags are encapsulated in metal-resistant ceramics and anchored to the roadway roof / sidewall with epoxy resin. They are deployed in a topological manner with spacing of ≤50 meters in straight sections and ≤20 meters in turning / fork sections. Ad hoc network communication module, which builds a Mesh network by LoRa nodes, including: Multi-hop routing engine, used to execute the improved AODVjr protocol and dynamically select paths based on cost; Link fault tolerance unit, used to broadcast detection frames every 30 seconds and automatically switch to the backup path in case of failure to ensure connectivity; Ground monitoring center module, including: A real-time positioning engine that parses coordinate data and maps it to a digital map of the well; The electronic fence alarm unit is used to determine whether people have entered the dangerous area based on the ray method and trigger a multi-level linkage response; The trajectory tracing database is used to store cloud data and synchronize it with local terminal records, supporting collaborative positioning interpolation algorithms to repair trajectory gaps.

10. The underground worker positioning and communication system based on RFID and communication according to claim 9, characterized in that: The personnel wear a terminal module, further comprising: Dual-frequency RFID scanning subunit, used to simultaneously support 125kHz-13.56MHz high-frequency data transmission, switching to high-frequency mode in metal-dense areas to improve signal-to-noise ratio; The IMU-assisted positioning subunit integrates inertial sensors and is used to start dead reckoning in turning / fork areas. When the RFID signal is lost, the Kalman filter is used to maintain positioning continuity. The positioning deviation compensation formula is: in, v is the terminal motion speed, a is the acceleration, Δt is the signal transmission time from t0 to t1; The emergency broadcast subunit is used to receive the alarm command issued by the LoRa network, drive the buzzer and red LED to flash, and warn people to evacuate.

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