Underground intelligent navigation system and positioning method based on multi-sensor fusion

Abstract

The invention discloses an underground intelligent navigation system based on multi-sensor fusion and a positioning method, and belongs to the technical field of mine navigation. An underground intelligent navigation system based on multi-sensor fusion is characterized by comprising a positioning base station network module, a mobile reflection terminal, a central control processing module and a monitoring center, according to the invention, the problems of low positioning precision and poor environmental adaptability under a mine in the prior art are solved. The advantages of high-frequency pulse signals and low-frequency magnetic field signals are combined, the temperature, humidity and air pressure in a mine are monitored and corrected through the environment sensing unit, accurate tracking of the positions of a mine car and miners in a complex environment is achieved, meanwhile, an efficient power consumption management mechanism and an emergency mode are designed, and the safety of the mine car and the miners is improved. And the practicability and the reliability are further enhanced.

Description

Technical Field

[0001] The present invention relates to the field of mine navigation technology, and in particular to an underground intelligent navigation system and positioning method based on multi-sensor fusion. Background Art

[0002] In underground environments such as mines, traditional positioning and navigation technologies struggle to meet actual needs due to a lack of GPS signal coverage. However, existing underground positioning solutions often suffer from low positioning accuracy, poor environmental adaptability, and suboptimal power consumption management. Previous technical solutions have attempted to use single-type sensors such as RFID and ultra-wideband (UWB) for positioning, but these methods often face challenges such as large positioning errors and sensitivity to environmental changes. Some positioning systems based on single-frequency signals experience significant changes in signal propagation characteristics when faced with humidity and temperature changes within mines, resulting in reduced positioning accuracy. Furthermore, some systems fail to effectively consider positioning and navigation conditions in emergencies, affecting the safe evacuation of personnel.

[0003] To ensure the safety of miners and improve work efficiency, there is an urgent need for a system that can provide precise positioning and reliable navigation in complex and closed underground environments. Summary of the Invention

[0004] The purpose of the present invention is to provide an underground intelligent navigation system and positioning method based on multi-sensor fusion, combining the advantages of high-frequency pulse signals and low-frequency magnetic field signals, and using environmental sensing units to monitor and correct the temperature, humidity and air pressure in the mine, thereby achieving accurate tracking of the positions of mine cars and miners in complex environments. At the same time, an efficient power consumption management mechanism and emergency mode are designed to further enhance its practicality and reliability, and solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: An underground intelligent navigation system based on multi-sensor fusion, comprising: The positioning base station network module is configured to transmit dual-frequency detection signals, including a 5.85GHz high-frequency pulse signal for measuring time difference and a 120kHz low-frequency magnetic field signal for measuring distance difference. It receives and analyzes the reflected signals from the mobile reflection terminal, collects the signal data, and uploads it to the central control and processing module. a mobile reflector terminal configured to receive a signal from the positioning base station network module, modulate and process the signal, and then scatter the signal to return it to the positioning base station network module; The central control processing module is configured to receive, fuse and calculate the data of the positioning base station network module, calculate the real-time position of the mobile reflector terminal in the mine, manage the navigation logic, and send the calculated positioning data and navigation data to the mobile reflector terminal for positioning and navigation feedback; The monitoring center is remotely connected to the central control and processing module and is configured to receive data uploaded by the central control and processing module. The monitoring center is also equipped with a display screen for displaying a three-dimensional map, which displays the positioning and movement trajectory of each mine car and miner in the entire mine in real time on the three-dimensional map.

[0006] Preferably, the positioning base station network module includes: A high-frequency transmitting unit configured to generate a 5.85 GHz pulse signal with a unique basic positioning base station ID; a low-frequency induction unit configured to generate a 120kHz alternating magnetic field; The synchronization control unit is equipped with a fiber optic timing network to synchronize the time between basic positioning base stations with an error of less than 15ns. The signal receiving unit is configured to receive the signal transmitted by the mobile reflector terminal and is also configured with a magnetoresistive sensor for detecting the degree of attenuation of magnetic field intensity (RSSI), obtaining the signal arrival time and the signal intensity attenuation change value, and filtering interference; The environmental sensing unit, including a temperature sensor, a humidity sensor and an air pressure sensor, is used to monitor the temperature, humidity and air pressure in the mine and to correct the pulse signal and magnetic field signal propagation parameters of the basic positioning base station.

[0007] Preferably, the positioning base station network module includes a plurality of basic positioning base stations, and the basic positioning base stations are arranged in the main transport tunnels, working face tunnels and intersections of the mine; The main transport lanes are deployed at a spacing of 45m, an installation height of 3.2m, and a radiation power of 22dBm. The working face tunnel deployment spacing is 31m, the installation height is 2.6m, and the radiation power is 27dBm; The deployment spacing at intersections is 15m, the installation height is 3.8m, and the radiation power is 15dBm.

[0008] Preferably, the mobile reflective terminal includes: Dual-frequency reflector unit, configured as an 8GHz ceramic antenna working in conjunction with a 120kHz induction coil; A coding and modulation unit configured to add a unique ID identifier and a timestamp of the current mobile reflection terminal to the reflection signal; The vibration activation unit is equipped with an acceleration sensor, which wakes up the mobile reflection terminal through the triggering of the acceleration sensor. After the acceleration sensor is stationary for a timeout, the mobile reflection terminal goes into sleep.

[0009] Preferably, the mobile reflective terminal is mounted in a human-computer interaction device, which includes a mine car terminal and a miner's imaging and indication helmet, and is configured to provide positioning results and navigation instructions; The mine car terminal is also equipped with indicator lights and whistles, which inform miners of the mine car's speed increase, deceleration, turn, start or stop through the indicator lights and whistles. The miner's imaging and indication helmet is also equipped with AR projection and voice broadcast to visualize the positioning results, project virtual navigation arrows on the mine ground, indicate the current location in real time by voice, and show the miner a thermal map of the dangerous area.

[0010] Preferably, the central control processing module includes: a data preprocessing unit configured to extract a time difference and a distance difference based on a signal arrival time and a signal strength attenuation change value; a dynamic weighting unit configured to assign weights to the time difference and the signal strength attenuation according to environmental noise and movement speed; A three-sided positioning unit is configured to input a weighted time difference and a distance difference and output a three-dimensional coordinate of the mobile reflector terminal through a three-sided positioning algorithm; A path planning unit is configured to generate a safe path and avoid dangerous areas in real time.

[0011] Preferably, the time difference and distance difference are extracted according to the signal arrival time and the signal strength attenuation change value, wherein: Time difference refers to the time difference between the same signal reaching the adjacent basic positioning base stations. The hyperbolic trajectory is constructed by the time difference, and its intersection is the position of the mobile reflection terminal; The distance difference refers to the distance between the mobile reflector terminal and the adjacent basic positioning base station. The magnetic field signal strength decays exponentially with increasing distance, and the distance is estimated based on the path loss model.

[0012] Preferably, the signal reflection terminal and the basic positioning base station start an emergency mode when communication is interrupted, and the emergency mode includes: The positioning base station uses low-frequency magnetic field signals to maintain basic positioning; The mobile reflective terminal switches to the minimum power consumption mode; Navigation instructions are simplified to a preset logic of evacuating along the right side of the mine tunnel.

[0013] A positioning method for an underground intelligent navigation system based on multi-sensor fusion is implemented based on an underground intelligent navigation system based on multi-sensor fusion, comprising the following steps: Step 1: Deploy basic positioning base stations according to the lane type, configure dual-frequency signal parameters, synchronize the time between basic positioning base stations through the optical fiber timing network, and poll the basic positioning base stations to transmit signals with a time window interval of 20ms. The basic positioning base stations send positioning requests for mobile reverse terminals to the central control processing module; Step 2: The mining car or miner wears a mobile reflection terminal, which is triggered by the acceleration sensor to wake up. The mobile reflection terminal establishes a ranging data link with the three nearest base stations. The mobile reflection terminal receives the signals sent by the three nearest basic positioning base stations and modulates the scattered signals. Step 3: Three adjacent basic positioning base stations receive the signal data of the mobile reverse terminal and upload the data to the central control processing module; Step 4: The central control processing module extracts the dual features of high-frequency signal time difference and low-frequency signal strength attenuation, calculates a first distance value based on the high-frequency signal time difference, calculates a second distance value based on the low-frequency signal strength attenuation, generates dynamic weights based on the moving speed and environmental noise, and solves the coordinates using a trilateration algorithm; Step 5: Output coordinates and navigate to the monitoring center and mobile reflector terminal.

[0014] Preferably, each of the mobile reflective terminals is assigned a unique terminal ID, and terminal ID identification is completed through a basic positioning base station.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses high-frequency pulse signals to measure time differences and low-frequency magnetic field signals to measure distance differences, and combines them with a three-sided positioning algorithm to achieve high-precision positioning of mine cars or miners in a mine environment.

[0016] 2. The present invention integrates multiple sensors to work together. Through temperature, humidity and air pressure sensors, it can monitor the environmental conditions in the mine and correct the signal propagation parameters of the basic positioning base station, thereby improving the accuracy and reliability of positioning in complex mine environments; the mobile reflection terminal is equipped with an acceleration sensor, which enables the mobile reflection terminal to start and stop automatically according to the situation to save power; and a magnetoresistive sensor is configured to obtain the signal strength attenuation change value to assist in improving positioning accuracy.

[0017] 3. The present invention can generate a safe path through the central control processing module, avoid dangerous areas in real time, and provide miners with clear positioning results and navigation instructions through human-computer interaction equipment. At the same time, the signal reflection terminal and the basic positioning base station can activate the emergency mode when communication is interrupted, thereby improving the safety and efficiency of operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the system module structure of the present invention; Figure 2Schematic diagram of the system workflow of the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] In order to solve the problems of low positioning accuracy and poor environmental adaptability of existing technologies in mines, please refer to Figure 1 and Figure 2 , this embodiment provides the following technical solutions: An underground intelligent navigation system based on multi-sensor fusion, comprising: The positioning base station network module is configured to transmit dual-frequency detection signals, including a 5.85GHz high-frequency pulse signal for measuring time difference and a 120kHz low-frequency magnetic field signal for measuring distance difference. It receives and analyzes the reflected signals from the mobile reflection terminal, collects the signal data, and uploads it to the central control and processing module. The positioning base station network module includes multiple basic positioning base stations, which are arranged in the main transportation tunnels, working face tunnels and intersections of the mine; The basic positioning base station is arranged as follows:

[0021] The positioning base station network module includes: A high-frequency transmitting unit configured to generate a 5.85 GHz pulse signal with a unique basic positioning base station ID; a low-frequency induction unit configured to generate a 120kHz alternating magnetic field; Synchronous control unit, equipped with a fiber optic timing network to synchronize the time between basic positioning base stations; The signal receiving unit is configured to receive the signal transmitted by the mobile reflective terminal and is also equipped with a magnetoresistive sensor for detecting the degree of attenuation of magnetic field intensity (RSSI), obtaining the signal arrival time and the signal intensity attenuation change value, and filtering interference; Environmental sensing unit, including temperature sensor, humidity sensor and air pressure sensor, is used to monitor the temperature, humidity and air pressure in the mine and correct the pulse signal and magnetic field signal propagation parameters of the basic positioning base station; The positioning base station network module uses high-frequency signals to measure time differences and low-frequency signals to measure distance differences. Combining the characteristics of the two signals further improves the system's positioning accuracy. The time between base stations is synchronized through the optical fiber timing network to ensure accurate time difference calculation and error control within 15ns, thereby improving positioning accuracy.

[0022] a mobile reflector terminal configured to receive a signal from the positioning base station network module, modulate and process the signal, and then scatter the signal to return it to the positioning base station network module; The mobile reflective terminal includes: Dual-frequency reflector unit, configured as an 8GHz ceramic antenna working in conjunction with a 120kHz induction coil; A coding and modulation unit configured to add a unique ID identifier and a timestamp of the current mobile reflection terminal to the reflection signal; The vibration activation unit is equipped with an acceleration sensor, which wakes up the mobile reflection terminal through the triggering of the acceleration sensor. After the acceleration sensor is stationary for a timeout, the mobile reflection terminal goes into sleep.

[0023] The mobile reflection terminal receives the signal from the positioning base station network module, modulates it, and scatters it back. The acceleration sensor is used to activate the wake-up signal. The reflected signal is accompanied by a unique ID and a timestamp code. Ensure that signals can be correctly identified and processed, while reducing power consumption, extending equipment life, and accurately tracking the location of miners or mining vehicles. In an emergency, switch to minimum power consumption mode to maintain basic functions.

[0024] The mobile reflective terminal is mounted in a human-computer interaction device, which includes a mine car terminal and a miner's imaging and indication helmet, and is configured to provide positioning results and navigation instructions; The mine car terminal is also equipped with indicator lights and whistles, which inform miners of the mine car's speed increase, deceleration, turn, start or stop through the indicator lights and whistles. The miner's visual indicator helmet is also equipped with AR projection and voice broadcast to visualize positioning results, project virtual navigation arrows on the mine floor, provide real-time voice instructions for current location, and display thermal maps of dangerous areas to miners; The central control processing module is configured to receive, fuse and calculate the data of the positioning base station network module, calculate the real-time position of the mobile reflector terminal in the mine, manage the navigation logic, and send the calculated positioning data and navigation data to the mobile reflector terminal for positioning and navigation feedback; The central control processing module includes: a data preprocessing unit configured to extract a time difference and a distance difference based on a signal arrival time and a signal strength attenuation change value; The time difference refers to the time difference between the same signal reaching the adjacent basic positioning base station. The hyperbolic trajectory is constructed by the time difference, and its intersection is the position of the mobile reflection terminal; The distance difference refers to the distance between the mobile reflector terminal and the adjacent basic positioning base station. The magnetic field signal strength decays exponentially with increasing distance, and the distance is estimated based on the path loss model. a dynamic weighting unit configured to assign weights to the time difference and the signal strength attenuation according to environmental noise and movement speed; A three-sided positioning unit is configured to input the weighted time difference and distance difference, output the three-dimensional coordinates of the mobile reflector terminal through a three-sided positioning algorithm, and output the three-dimensional coordinates; A path planning unit is configured to generate a safe path and avoid dangerous areas in real time.

[0025] The central control processing module dynamically adjusts the weights based on factors such as environmental noise and movement speed to adapt to the precise positioning requirements in complex mining environments. It can effectively provide real-time, accurate location information and safe path planning, helping miners and mining vehicles avoid dangerous areas.

[0026] The monitoring center is set up above the mine tunnel and is remotely connected to the central control processing module. It is configured to receive data uploaded by the central control processing module. The monitoring center is also equipped with a display screen for displaying three-dimensional maps. The positioning and movement trajectory of each mine car and miner in the entire mine are displayed in real time on the three-dimensional map, providing ground management personnel with an intuitive monitoring interface, facilitating rapid response to emergencies, enhancing the ability to control the internal situation of the mine, and improving safety.

[0027] A positioning method for an underground intelligent navigation system based on multi-sensor fusion is implemented based on an underground intelligent navigation system based on multi-sensor fusion, comprising the following steps: Step 1: Preparation stage: Deploy basic positioning base stations according to lane types and configure dual-frequency signal parameters; Synchronize the time between basic positioning base stations through the optical fiber timing network; The basic positioning base station polls and transmits signals with a time window interval of 20ms; Assign a unique terminal ID to each mobile reflective terminal; The basic positioning base station uses a multi-user detection algorithm to separate mixed signals and identify terminal IDs; The basic positioning base station sends a positioning request for the mobile reverse terminal to the central control processing module; Step 2: The mining vehicle or miner wears a mobile reflective terminal, and the acceleration sensor triggers wake-up; The mobile reflector terminal establishes a ranging data link with the three nearest base stations to complete terminal ID identification; The mobile reflection terminal receives the signals from the three closest basic positioning base stations and modulates the scattered signals; Step 3: The three basic positioning base stations receive the ID identification and distance value data and upload them to the central control processing module; Step 4: The central control processing module performs time difference ranging, signal strength calculation, three-sided positioning calculation and motion trajectory prediction; Extract the dual features of TDOA time difference and RSSI attenuation, calculate the first distance value by high-frequency signal time difference (TDOA), and calculate the second distance value by low-frequency signal strength attenuation (RSSI); Generate dynamic weights based on movement speed and ambient noise, and calculate coordinates using a three-sided positioning algorithm; Step 5: Output coordinates and navigate to the monitoring center and mobile reflector terminal.

[0028] The human-computer interaction device activates emergency mode when communication is interrupted. In emergency mode, the positioning base station uses low-frequency magnetic field signals to maintain basic positioning functions, and the mobile reflective terminal switches to minimum power consumption mode, responding only to 120kHz signals. Navigation instructions are simplified to a preset logic of evacuating along the right side of the alley. This design ensures the safe evacuation of personnel in the event of an emergency.

[0029] Finally, the positioning accuracy of the system is tested, and the test results are as follows:

[0030] As shown in the table above, the positioning accuracy of the system is good, and the maximum error can be controlled within about 2m.

[0031] Working Principle: The positioning base station network module transmits a dual-frequency detection signal and receives a reflected signal modulated by a mobile reflector terminal. These signals contain time and distance information, and synchronization between base stations is ensured via a fiber-optic timing network. Upon receiving the signal, the mobile reflector terminal, carried by a miner or mining vehicle, activates and wakes up via its accelerometer. It then modulates a signal containing a unique ID and timestamp and returns it to the nearest basic positioning base station. Data from three neighboring base stations is used to calculate the mobile reflector terminal's exact location. The central control processing module uses a trilateration algorithm combined with environmental parameter corrections to calculate three-dimensional coordinates and simultaneously generates navigation instructions that are sent to the mobile reflector terminal.

[0032] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0033] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. An underground intelligent navigation system based on multi-sensor fusion, characterized in that: It includes positioning base station network module, mobile reflection terminal, central control processing module and monitoring center; The positioning base station network module is configured to transmit dual-frequency detection signals, including a high-frequency pulse signal for measuring time difference and a low-frequency magnetic field signal for measuring distance difference, receive and analyze the reflected signal from the mobile reflection terminal, collect the signal data and upload it to the central control processing module; The mobile reflection terminal is configured to receive a signal from the positioning base station network module, modulate the signal and then scatter it, and return the signal to the positioning base station network module; The central control processing module is configured to receive, fuse and calculate the data of the positioning base station network module, calculate the real-time position of the mobile reflector terminal in the mine, and send the calculated positioning data and navigation data to the mobile reverse terminal for positioning and navigation feedback; The monitoring center is remotely connected to the central control processing module and is configured to receive data uploaded by the central control processing module. The monitoring center is also equipped with a display screen for displaying a three-dimensional map, which displays the positioning and movement trajectory of each mine car and miner in the entire mine in real time on the three-dimensional map.

2. The multi-sensor fusion downhole intelligent navigation system according to claim 1, characterized in that: The positioning base station network module includes: A high frequency transmitting unit configured to generate a pulse signal with a unique basic positioning base station ID identifier; a low-frequency sensing unit configured to generate a ranging magnetic field; Synchronous control unit, equipped with a fiber optic timing network to synchronize the time between basic positioning base stations; A signal receiving unit is configured to receive the signal transmitted by the mobile reflective terminal and is also configured with a magnetoresistive sensor for detecting the attenuation degree of the magnetic field intensity, thereby obtaining the signal arrival time and the signal intensity attenuation change value; The environmental sensing unit, including a temperature sensor, a humidity sensor and an air pressure sensor, is used to monitor the temperature, humidity and air pressure in the mine and to correct the pulse signal and magnetic field signal propagation parameters of the basic positioning base station.

3. The multi-sensor fusion downhole intelligent navigation system according to claim 1, characterized in that: The positioning base station network module includes a plurality of basic positioning base stations, which are arranged in the main transport lanes, working face lanes and intersections of the mine; The main transport lanes are deployed at a spacing of 45m, an installation height of 3.2m, and a radiation power of 22dBm. The working face tunnel deployment spacing is 31m, the installation height is 2.6m, and the radiation power is 27dBm; The deployment spacing at intersections is 15m, the installation height is 3.8m, and the radiation power is 15dBm.

4. The multi-sensor fusion downhole intelligent navigation system according to claim 1, characterized in that: The mobile reflective terminal includes: A dual-frequency reflection unit configured with a ceramic antenna and an induction coil to collaboratively reflect signals; A coding and modulation unit configured to add a unique ID identifier and a timestamp of the current mobile reflection terminal to the reflection signal; The vibration activation unit is equipped with an acceleration sensor, which wakes up the mobile reflection terminal through the triggering of the acceleration sensor. After the acceleration sensor is stationary for a timeout, the mobile reflection terminal goes into sleep.

5. The multi-sensor fusion downhole intelligent navigation system according to claim 4, characterized in that: The mobile reflective terminal is mounted in a human-computer interaction device, which includes a mine car terminal and a miner's imaging and indication helmet, and is configured to provide positioning results and navigation instructions; The mine car terminal is also equipped with indicator lights and whistles, which inform miners of the mine car's speed increase, deceleration, turn, start or stop through the indicator lights and whistles. The miner's imaging and indication helmet is also equipped with AR projection and voice broadcast to visualize the positioning results, project virtual navigation arrows on the mine ground, indicate the current location in real time by voice, and show the miner a thermal map of the dangerous area.

6. The multi-sensor fusion downhole intelligent navigation system according to claim 1, characterized in that: The central control processing module includes: a data preprocessing unit configured to extract a time difference and a distance difference based on a signal arrival time and a signal strength attenuation change value; a dynamic weighting unit configured to assign weights to the time difference and the signal strength attenuation according to environmental noise and movement speed; A three-sided positioning unit is configured to input weighted time difference and distance difference and output the three-dimensional coordinates of the mobile reflector terminal through a three-sided positioning algorithm; A path planning unit is configured to generate a safe path and avoid dangerous areas in real time.

7. The multi-sensor fusion downhole intelligent navigation system according to claim 6, characterized in that: The time difference and distance difference are extracted according to the signal arrival time and the signal strength attenuation change value, wherein: Time difference refers to the time difference between the same signal reaching the adjacent basic positioning base stations. The hyperbolic trajectory is constructed by the time difference, and its intersection is the position of the mobile reflection terminal; The distance difference refers to the distance between the mobile reflector terminal and the adjacent basic positioning base station. The magnetic field signal strength decays exponentially with increasing distance, and the distance is estimated based on the path loss model.

8. The multi-sensor fusion downhole intelligent navigation system according to claim 1, characterized in that: The mobile reflector terminal and the basic positioning base station start the emergency mode when the communication is interrupted. The emergency mode includes: The positioning base station uses low-frequency magnetic field signals to maintain basic positioning; The mobile reflective terminal switches to the minimum power consumption mode; Navigation instructions are simplified to a preset logic of evacuating along the right side of the mine tunnel.

9. A positioning method for a downhole intelligent navigation system based on multi-sensor fusion, implemented based on the downhole intelligent navigation system according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Deploy basic positioning base stations according to the lane type, configure dual-frequency signal parameters, synchronize the time between basic positioning base stations through the optical fiber timing network, and poll the basic positioning base stations to transmit signals with a time window interval of 20ms. The basic positioning base stations send positioning requests for mobile reverse terminals to the central control processing module; Step 2: The mining car or miner wears a mobile reflection terminal, which is triggered by the acceleration sensor to wake up. The mobile reflection terminal establishes a ranging data link with the three nearest base stations. The mobile reflection terminal receives the signals sent by the three nearest basic positioning base stations and modulates the scattered signals. Step 3: Three adjacent basic positioning base stations receive the signal data of the mobile reverse terminal and upload the data to the central control processing module; Step 4: The central control processing module extracts the dual features of high-frequency signal time difference and low-frequency signal strength attenuation, calculates a first distance value based on the high-frequency signal time difference, calculates a second distance value based on the low-frequency signal strength attenuation, generates dynamic weights based on the moving speed and environmental noise, and solves the coordinates using a trilateration algorithm; Step 5: Output coordinates and navigate to the monitoring center and mobile reflector terminal.

10. The positioning method of an underground intelligent navigation system based on multi-sensor fusion according to claim 9, characterized in that: Each of the mobile reflective terminals is assigned a unique terminal ID, and terminal ID identification is completed through the basic positioning base station.

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