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

Abstract

The application discloses an underground intelligent navigation system and positioning method based on multi-sensor fusion and belongs to the technical field of mine navigation. The 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. The application solves the problems of low positioning accuracy and poor environmental adaptability of the prior art in a mine. The application combines the advantages of high-frequency pulse signals and low-frequency magnetic field signals, monitors and corrects the temperature, humidity and air pressure in the mine by using an environmental sensing unit, realizes accurate tracking of the positions of mine cars and miners in a complex environment, and further enhances the practicability and reliability by designing an efficient power consumption management mechanism and an emergency mode.

Description

TECHNICAL FIELD

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

[0002] In underground environments such as mines, traditional positioning and navigation technologies are difficult to meet actual needs due to the lack of GPS signal coverage. However, existing underground positioning solutions often have problems such as low positioning accuracy, poor environmental adaptability, and unsatisfactory power consumption management. In previous technical solutions, although single type sensors such as RFID, ultra-wideband (UWB) were used for positioning attempts, these methods usually face challenges such as large positioning error and sensitivity to environmental changes. Some positioning systems based on single frequency signals have significant changes in signal propagation characteristics when facing humidity and temperature changes in mines, resulting in decreased positioning accuracy. In addition, some systems fail to effectively consider the positioning and navigation conditions in emergency situations, 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 accurate positioning and reliable navigation in complex and closed underground environments. SUMMARY

[0004] The present application aims 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 temperature, humidity, and air pressure in mines, achieving accurate tracking of mine car and miner positions in complex environments. In addition, an efficient power consumption management mechanism and emergency mode are designed to further enhance the practicality and reliability of the system, solving the problems raised in the background technology.

[0005] To achieve the above purpose, the present application provides the following technical solutions:

[0006] An underground intelligent navigation system based on multi-sensor fusion, comprising:

[0007] A positioning base station network module 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, receive and analyze reflected signals from mobile reflection terminals, and upload signal data to a central control processing module after collection;

[0008] A mobile reflection terminal configured to receive signals from the positioning base station network module, modulate and process the signals, scatter them, and return them to the positioning base station network module;

[0009] A central control processing module is configured to receive, fuse and calculate data of the positioning base station network module, to calculate real-time position of the mobile reflection terminal in the mine, to manage navigation logic, and to send the calculated positioning data and navigation data to the mobile reflection terminal for positioning and navigation feedback.

[0010] A monitoring center is in signal connection with the central control processing module remotely, configured to receive data uploaded by the central control processing module, and the monitoring center is further configured with a display screen for displaying a three-dimensional map, in which the positioning and movement trajectory of each mine car and miner in the whole mine are displayed in real time.

[0011] Preferably, the positioning base station network module comprises:

[0012] A high-frequency transmitting unit is configured to generate a 5.85GHz pulse signal with a unique basic positioning base station ID;

[0013] A low-frequency induction unit is configured to generate a 120kHz alternating magnetic field;

[0014] A synchronous control unit is configured with an optical fiber timing network to synchronize time among the basic positioning base stations, with an error controlled within 15ns;

[0015] A signal receiving unit is configured to receive signals returned by the mobile reflection terminal, and is further configured with a magnetic resistance sensor for detecting magnetic field intensity attenuation degree (RSSI), to obtain signal arrival time and signal strength attenuation change value, and to filter interference;

[0016] An environmental sensing unit comprises a temperature sensor, a humidity sensor and a barometric pressure sensor, for monitoring temperature, humidity and barometric pressure in the mine, and correcting propagation parameters of pulse signals and magnetic field signals of the basic positioning base stations.

[0017] Preferably, the positioning base station network module comprises a plurality of basic positioning base stations, which are arranged in main transportation roadways, working face roadways and intersections of the mine;

[0018] The main transportation roadways have a deployment interval of 45m, an installation height of 3.2m and a radiation power of 22dBm;

[0019] The working face roadways have a deployment interval of 31m, an installation height of 2.6m and a radiation power of 27dBm;

[0020] The intersections have a deployment interval of 15m, an installation height of 3.8m and a radiation power of 15dBm.

[0021] Preferably, the mobile reflection terminal comprises:

[0022] A dual-frequency reflection unit is configured to work in cooperation with an 8GHz ceramic antenna and a 120kHz induction coil;

[0023] The encoding modulation unit is configured to add a unique ID of the current mobile reflection terminal and a time stamp in the reflection signal.

[0024] The vibration activation unit is configured with an acceleration sensor, and the mobile reflection terminal is awakened by triggering the acceleration sensor. After the acceleration sensor is static for a long time, the mobile reflection terminal is in sleep mode.

[0025] Preferably, the mobile reflection terminal is mounted in a human-computer interaction device, which includes a mine car terminal and a miner display indication helmet, and is configured to provide positioning results and navigation instructions.

[0026] The mine car terminal is also provided with an indicator light and a siren, which prompts the miner to speed up, slow down, turn, start or stop the mine car through the indicator light and siren sound.

[0027] The miner display indication helmet is also provided with AR projection and voice broadcast, so that the positioning results can be visualized, the virtual navigation arrow is projected on the mine road surface, the real-time voice indicates the current position, and the thermal map of the dangerous area is displayed to the miner.

[0028] Preferably, the center control processing module comprises:

[0029] The data preprocessing unit is configured to extract time difference and distance difference according to signal arrival time and signal strength attenuation change value.

[0030] The dynamic weighting unit is configured to assign weights of time difference and signal strength attenuation according to environmental noise and moving speed.

[0031] The three-edge positioning unit is configured to input the weighted time difference and distance difference, and output the three-dimensional coordinates of the mobile reflection terminal through the three-edge positioning algorithm.

[0032] The path planning unit is configured to generate a safe path to avoid dangerous areas in real time.

[0033] Preferably, the time difference and distance difference are extracted according to the signal arrival time and the signal strength attenuation change value, wherein:

[0034] The time difference refers to the time difference of the same signal arriving at adjacent basic positioning base stations. The hyperbolic trajectory is constructed by the time difference, and the intersection point is the position of the mobile reflection terminal.

[0035] The distance difference refers to the distance between the mobile reflection terminal and the adjacent basic positioning base station. The magnetic field signal strength decreases exponentially with the increase of distance, and the distance is estimated based on the path loss model.

[0036] Preferably, the signal reflection terminal and the basic positioning base station start the emergency mode when the communication is interrupted, and the emergency mode comprises:

[0037] The positioning base station adopts a low-frequency magnetic field signal to maintain basic positioning;

[0038] The mobile reflection terminal switches to a minimum power consumption mode;

[0039] The navigation instruction is simplified to a preset logic of evacuating along the right side of the mine roadway.

[0040] A positioning method of an underground intelligent navigation system based on multi-sensor fusion, realized based on an underground intelligent navigation system based on multi-sensor fusion, comprises the following steps:

[0041] Step one, deploy basic positioning base stations according to the type of the roadway, configure double-frequency signal parameters, synchronize the time between the basic positioning base stations through an optical fiber timing network, the basic positioning base stations poll the transmitted signals with a time window interval of 20 ms, and the basic positioning base stations send a positioning request for a mobile reflection terminal to a central control processing module;

[0042] Step two, the miner or the mine car wears a mobile reflection terminal, an acceleration sensor triggers wake-up, the mobile reflection terminal establishes a ranging data link with the three nearest base stations, the mobile reflection terminal receives the modulated scattered signals emitted by the three nearest basic positioning base stations;

[0043] Step three, the three adjacent basic positioning base stations receive the signal data of the mobile reflection terminal and upload the data to the central control processing module;

[0044] Step four, the central control processing module extracts the high-frequency signal time difference and the low-frequency signal strength attenuation double features, calculates a first distance value through the high-frequency signal time difference, calculates a second distance value through the low-frequency signal strength attenuation, generates a dynamic weight based on the mobile speed and the environmental noise, and solves the coordinates through a three-edge positioning algorithm;

[0045] Step five, output the coordinates and navigation to the monitoring center and the mobile reflection terminal.

[0046] Preferably, the mobile reflection terminal is uniformly allocated with a unique terminal ID identification, and the terminal ID identification is identified through the basic positioning base station.

[0047] Compared with the prior art, the present application has the following beneficial effects:

[0048] 1. The present application realizes high-precision positioning of the mine car or the miner in the mine environment by using a high-frequency pulse signal to measure the time difference and a low-frequency magnetic field signal to measure the distance difference, and combining a three-edge positioning algorithm.

[0049] 2、The present application fuses multiple sensors to work cooperatively, through temperature, humidity and barometric pressure sensors, the environmental conditions in the mine can be monitored and the signal propagation parameters of the base positioning base station are corrected, the accuracy and reliability of positioning in complex mine environment are improved; the mobile reflection terminal is equipped with an acceleration sensor, which can start and stop automatically according to the situation, so as to save power; the magnetic resistance sensor is configured to obtain the signal strength attenuation change value, which can assist to improve the positioning accuracy.

[0050] 3、The present application can generate a safe path through the central control processing module, avoid dangerous areas in real time, and provide clear positioning results and navigation instructions to miners through human-computer interaction equipment, and the signal reflection terminal and the base positioning base station can start the emergency mode when the communication is interrupted, thereby improving the safety and efficiency of operation. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 It is a schematic diagram of the system module structure of the present application;

[0052] Figure 2 It is a schematic diagram of the system workflow of the present application. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0054] In order to solve the problems of low positioning accuracy and poor environmental adaptability of the prior art in the mine, please refer to Figure 1 and Figure 2 The technical solutions provided by the present embodiment are as follows:

[0055] An underground intelligent navigation system based on multi-sensor fusion, comprising:

[0056] A positioning base station network module 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, receive and analyze the reflection signals of the mobile reflection terminal, and upload the signal data to the central control processing module after collection;

[0057] The positioning base station network module comprises a plurality of base positioning base stations, and the base positioning base stations are arranged in the main transportation roadway, the working face roadway and the intersection of the mine;

[0058] The base positioning base station is arranged as follows:

[0059]

[0060] The positioning base station network module comprises:

[0061] A high-frequency transmitting unit configured to generate a 5.85 GHz pulse signal with a unique base positioning base station ID;

[0062] A low-frequency induction unit configured to generate a 120 kHz alternating magnetic field;

[0063] A synchronous control unit configured with an optical fiber timing network to synchronize the time between base positioning base stations;

[0064] A signal receiving unit configured to receive signals returned by a mobile reflection terminal, and further configured with a magnetic resistance sensor to detect the degree of magnetic field intensity attenuation (RSSI), to obtain the signal arrival time and signal strength attenuation change value, and to filter interference;

[0065] An environmental sensing unit comprising a temperature sensor, a humidity sensor, and a barometric pressure sensor, for monitoring the temperature, humidity, and barometric pressure in the mine, and correcting the propagation parameters of the pulse signal and the magnetic field signal of the base positioning base station;

[0066] The positioning base station network module uses high-frequency signals to measure time differences and low-frequency signals to measure distance differences, and combines the characteristics of the two types of signals to further improve the positioning accuracy of the system. The optical fiber timing network synchronizes the time between base stations to ensure accurate time difference calculation with an error of less than 15 ns, thereby improving positioning accuracy.

[0067] The mobile reflection terminal is configured to receive signals from the positioning base station network module, modulate and process the signals, scatter the signals, and return the signals to the positioning base station network module;

[0068] The mobile reflection terminal comprises:

[0069] A dual-frequency reflection unit configured to work in cooperation with an 8 GHz ceramic antenna and a 120 kHz induction coil;

[0070] A coding and modulation unit configured to add a unique ID of the current mobile reflection terminal and a timestamp to the reflected signal;

[0071] A vibration activation unit configured with an acceleration sensor to wake up the mobile reflection terminal through the triggering of the acceleration sensor. After the acceleration sensor is stationary for a certain period of time, the mobile reflection terminal goes into hibernation.

[0072] The mobile reflection terminal receives signals from the positioning base station network module, modulates and processes the signals, and scatters the signals back. The acceleration sensor is used for activation and wake-up. The reflected signal is accompanied by a unique ID and a timestamp code,

[0073] Ensure that the signal can be correctly identified and processed, while reducing power consumption, prolong the service life of the device, to achieve the precise tracking of the position of the miner or mine car, switch to the minimum power consumption mode in emergency to maintain the basic functions.

[0074] The mobile reflection terminal is mounted in the human-computer interaction device, which includes a mine car terminal and a miner display indication helmet, configured to provide positioning results and navigation instructions;

[0075] The mine car terminal is also provided with an indicator light and a siren, which prompts the miner to speed up, slow down, turn, start or stop the mine car through the indicator light and siren sound;

[0076] The miner display indication helmet is also provided with AR projection and voice broadcast, which visualizes the positioning results, projects virtual navigation arrows on the mine tunnel ground, and real-time voice indicates the current position, and displays the heat map of the dangerous area to the miner;

[0077] The center 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 reflection terminal in the mine, manage the navigation logic, and send the calculated positioning data and navigation data to the mobile reflection terminal for positioning and navigation feedback;

[0078] The center control processing module includes:

[0079] The data preprocessing unit is configured to extract the time difference and distance difference according to the signal arrival time and signal strength attenuation change value;

[0080] The time difference refers to the time difference of the same signal arriving at adjacent basic positioning base stations, and the hyperbolic trajectory is constructed through the time difference, and the intersection point is the position of the mobile reflection terminal;

[0081] The distance difference refers to the distance between the mobile reflection terminal and the adjacent basic positioning base station, and the magnetic field signal strength decreases exponentially with the increase of distance, and the distance is estimated based on the path loss model;

[0082] The dynamic weighting unit is configured to allocate the weight of the time difference and the signal strength attenuation according to the environmental noise and the moving speed;

[0083] The three-dimensional positioning unit is configured to input the weighted time difference and distance difference, and output the three-dimensional coordinates of the mobile reflection terminal through the three-dimensional positioning algorithm;

[0084] The path planning unit is configured to generate a safe path to avoid dangerous areas in real time.

[0085] The center control processing module dynamically adjusts the weight according to factors such as environmental noise and moving speed, so as to adapt to the accurate positioning demand in a complex mine environment, and can effectively provide real-time and accurate position information and safe path planning, so as to help the miners and mine cars to avoid dangerous areas.

[0086] The monitoring center is arranged above the mine tunnel and is remotely connected with the center control processing module, and is configured to receive the data uploaded by the center control processing module. The monitoring center is also provided with a display screen for displaying a three-dimensional map, and the positioning and moving track of each mine car and miner in the whole mine are displayed in the three-dimensional map in real time, so as to provide an intuitive monitoring interface for the ground management personnel, facilitate quick response to emergencies, enhance the control ability of the internal situation of the mine, and improve the safety.

[0087] A positioning method of an underground intelligent navigation system based on multi-sensor fusion, realized based on an underground intelligent navigation system based on multi-sensor fusion, comprising the following steps:

[0088] Step one, preparation stage:

[0089] Deploy the basic positioning base station according to the type of the roadway, and configure the dual-frequency signal parameters;

[0090] Synchronize the time between the basic positioning base stations through the optical fiber timing network;

[0091] The basic positioning base station polls the transmitted signal with a time window interval of 20 ms;

[0092] Assign a unique terminal ID to each mobile reflection terminal;

[0093] The basic positioning base station separates the mixed signal by using a multi-user detection algorithm and identifies the terminal ID;

[0094] The basic positioning base station sends a positioning request for the mobile reflection terminal to the center control processing module;

[0095] Step two, the miner or the mine car wears the mobile reflection terminal, and the acceleration sensor triggers the wake-up;

[0096] The mobile reflection terminal establishes a ranging data link with the three nearest base stations, and completes the terminal ID identification;

[0097] The mobile reflection terminal receives the signal modulated and scattered by the three nearest basic positioning base stations;

[0098] Step three, the three basic positioning base stations receive the ID identification and distance value data, and upload them to the center control processing module;

[0099] Step four, the center control processing module performs time difference ranging, signal strength calculation, three-dimensional positioning calculation and motion trajectory prediction;

[0100] Extract the TDOA time difference and RSSI attenuation double characteristics, calculate the first distance value through the high frequency signal time difference (TDOA), and calculate the second distance value through the low frequency signal strength attenuation (RSSI);

[0101] Generate dynamic weight based on mobile speed and environmental noise, and solve the coordinates through trilateration algorithm;

[0102] Step five, output coordinates and navigation to monitoring center and mobile reflection terminal.

[0103] The man-machine interaction device starts the emergency mode when the communication is interrupted. In the emergency mode, the positioning base station uses low frequency magnetic field signal to maintain the basic positioning function, the mobile reflection terminal switches to the minimum power consumption mode, only responds to 120kHz signal, and the navigation instruction is simplified to the preset logic of evacuating along the right side of the tunnel. This design ensures the safety evacuation of personnel in the event of an emergency.

[0104] Finally, the positioning accuracy of the system is tested, and the test results are as follows:

[0105]

[0106] As shown in the above table, the positioning accuracy of the system is good, and the maximum error can be controlled at about 2m.

[0107] Working principle: The positioning base station network module transmits dual-frequency detection signals and receives the reflected signals modulated by the mobile reflection terminal. These signals contain time difference and distance difference information, and the time synchronization between the base stations is ensured through the optical fiber timing network. The mobile reflection terminal carried by the miner or mine car receives the signal, activates the wake-up through the acceleration sensor, and modulates the signal containing the unique ID and timestamp to return to the nearest basic positioning base station. The data of the three adjacent base stations is used to calculate the exact position of the mobile reflection terminal. The central control processing module uses the trilateration algorithm combined with environmental parameter correction to solve the three-dimensional coordinates and generate navigation instructions to the mobile reflection terminal.

[0108] It should be noted that in this text, relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the term "includes", "contains" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0109] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and changes can be made by those skilled in the art without departing from the spirit and principles of the present application.

Claims

1. A downhole intelligent navigation system based on multi-sensor fusion, characterized in that, It includes a positioning base station network module, a mobile reflective terminal, a central control and processing module, and a 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 signals from the mobile reflective terminal; and upload the signal data to the central control processing module after acquisition. The positioning base station network module includes: The high-frequency transmitting unit is configured to generate a pulse signal with a unique basic positioning base station ID. A low-frequency sensing unit is configured to generate a ranging magnetic field; The synchronization control unit is equipped with a fiber optic time synchronization network to synchronize the time between the basic positioning base stations. The signal receiving unit is configured to receive signals transmitted back by the mobile reflective terminal, and is also equipped with a magnetoresistive sensor to detect the degree of magnetic field strength attenuation, and to obtain the signal arrival time and the signal strength attenuation change value. The environmental sensing unit includes a temperature sensor, a humidity sensor, and a pressure sensor, which are used to monitor the temperature, humidity, and pressure in the mine and correct the propagation parameters of the pulse signal and magnetic field signal of the basic positioning base station. The mobile reflective terminal is configured to receive signals from the positioning base station network module, modulate the signals, scatter them, and return the signals to the positioning base station network module. The mobile reflective terminal includes: The dual-frequency reflection unit is configured to reflect signals in conjunction with a ceramic antenna and an induction coil. The coding and modulation unit is configured to add a unique ID identifier and timestamp of the current mobile reflecting terminal to the reflected signal; The vibration activation unit is equipped with an acceleration sensor. The mobile reflection terminal is woken up by the acceleration sensor. After the acceleration sensor remains stationary for a timeout, the mobile reflection terminal goes into sleep mode. The central control processing module is configured to receive, fuse, and calculate data from the positioning base station network module, calculate the real-time location of the mobile reflective terminal in the mine, and simultaneously send the calculated positioning and navigation data to the mobile reflective terminal for positioning and navigation feedback. The central control processing module includes: The data preprocessing unit is configured to extract the time difference and distance difference based on the signal arrival time and the signal strength attenuation change value; The dynamic weighting unit is configured to assign weights to time difference and signal strength attenuation based on ambient noise and movement speed; The trilateration unit is configured to take the weighted time difference and distance difference as inputs and output the three-dimensional coordinates of the mobile reflective terminal through the trilateration algorithm. The path planning unit is configured to generate safe paths and avoid dangerous areas in real time. 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 location and movement trajectory of each mine car and miner in the entire mine in real time.

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

3. The downhole intelligent navigation system with multi-sensor fusion according to claim 1, characterized in that, The mobile reflective terminal is mounted in a human-machine interaction device, which includes a mining truck terminal and a miner's display helmet, and is configured to provide positioning results and navigation instructions. The mine car terminal is also equipped with indicator lights and a horn, which use the indicator lights and horn sounds to prompt miners to accelerate, decelerate, turn, start or stop the mine car; The miner's visual guidance helmet is also equipped with AR projection and voice broadcast, which makes the positioning results visible, projects virtual navigation arrows on the mine tunnel surface, provides real-time voice instructions on the current location, and displays heat maps of dangerous areas to the miners.

4. The downhole intelligent navigation system with multi-sensor fusion according to claim 1, characterized in that, The time difference and distance difference are extracted based on the signal arrival time and the signal strength attenuation change value, wherein: The time difference refers to the time difference between the arrival of the same signal at the nearest basic positioning base station. A hyperbolic trajectory is constructed by the time difference, and the intersection point is the location of the mobile reflective terminal. The distance difference refers to the distance between the mobile reflective terminal and the nearest basic positioning base station. The magnetic field signal strength decreases exponentially with increasing distance, and the distance is estimated based on the path loss model.

5. The downhole intelligent navigation system with multi-sensor fusion according to claim 1, characterized in that, When communication between the mobile reflective terminal and the basic positioning base station is interrupted, an emergency mode is activated, which includes: The positioning base station uses low-frequency magnetic field signals to maintain basic positioning; The mobile reflective terminal switches to minimum power consumption mode; The navigation instructions are simplified to the preset logic of evacuating along the right side of the mine roadway.

6. A positioning method for a downhole intelligent navigation system based on multi-sensor fusion, implemented based on the downhole intelligent navigation system based on multi-sensor fusion as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Deploy basic positioning base stations according to the type of alleyway, configure dual-frequency signal parameters, synchronize the time between basic positioning base stations through the fiber optic time synchronization network, and have the basic positioning base stations poll and transmit signals with a time window interval of 20ms. The basic positioning base stations send positioning requests for the mobile reverse terminal to the central control processing module. Step 2: The mining vehicle or miner wears a mobile reflective terminal, which is triggered by the accelerometer to wake up. The mobile reflective terminal establishes a ranging data link with the three nearest base stations. The mobile reflective terminal receives the signals sent by the three nearest basic positioning base stations and modulates the backscattered signal. Step 3: The three nearby basic positioning base stations receive the signal data from 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. It calculates the first distance value through the high-frequency signal time difference and the second distance value through the low-frequency signal strength attenuation. It generates dynamic weights based on the moving speed and environmental noise and solves the coordinates through the trilateration algorithm. Step 5: Output coordinates and navigate to the monitoring center and mobile reflection terminal.

7. A positioning method for a downhole intelligent navigation system based on multi-sensor fusion according to claim 6, characterized in that, Each mobile reflective terminal is assigned a unique terminal ID, which is identified by the basic positioning base station.

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