Tunnel vehicle positioning device

Abstract

The utility model discloses a tunnel vehicle positioning device. The tunnel vehicle positioning device comprises a UWB positioning module, a three-axis geomagnetic sensor, an inertial measurement unit and a wireless communication module which are installed on a vehicle chassis. The UWB positioning module comprises a receiving and transmitting antenna, UWB positioning anchor points are arranged on the side wall of the tunnel at intervals, and each UWB positioning anchor point is fixed to a support on the side wall of the tunnel; geomagnetic reference point arrays are embedded in the tunnel ground, and geomagnetic reference points are formed by packaging permanent magnets and stainless steel shells and are symmetrically arranged along the longitudinal center line of the tunnel at intervals; the inertial measurement unit comprises a three-axis gyroscope and an accelerometer; a transmitting antenna of the wireless communication module is installed on the top of a vehicle, and a receiving antenna is located in the center of a tunnel vault. The method can help to improve the problem of positioning failure of the vehicle in the tunnel.

Description

TECHNICAL FIELD

[0001] The utility model relates to vehicle positioning related technical field. More specifically, the utility model relates to a tunnel vehicle positioning device. BACKGROUND

[0002] In a closed environment such as a tunnel, the real-time positioning of a vehicle mainly relies on a combination scheme of a satellite positioning system (such as GPS, Beidou) and an inertial measurement unit (IMU), but both have significant defects: satellite signals cannot penetrate at all due to the physical obstruction of the tunnel structure, and the vehicle loses the positioning ability immediately after entering the tunnel, resulting in navigation interruption. Even if an enhanced satellite receiving module (such as a high-sensitivity antenna) is used, its positioning delay and drift error still cannot meet the high-precision scene requirements of automatic driving or vehicle fleet coordination. The inertial measurement unit (IMU) calculates the vehicle pose through a three-axis gyroscope and an accelerometer, but the angle error accumulates with time in a quadratic manner. In a long tunnel, the position calculation error of the IMU can reach several meters or even tens of meters after the vehicle has been driving for more than 1 minute, and there is a lack of external reference points for correction. Therefore, it is necessary to design a technical scheme that can overcome the above-mentioned defects. SUMMARY

[0003] An object of the utility model is to provide a tunnel vehicle positioning device that can help improve the positioning failure problem of a vehicle in a tunnel.

[0004] In order to achieve these objects and other advantages of the utility model, according to one aspect of the utility model, a tunnel vehicle positioning device is provided, which comprises a UWB positioning module, a three-axis geomagnetic sensor, an inertial measurement unit and a wireless communication module installed on a vehicle chassis; the UWB positioning module contains a transceiver antenna, UWB positioning anchor points are arranged at intervals on the side walls of the tunnel, and each UWB positioning anchor point is fixed on a bracket of the side wall of the tunnel; a tunnel ground pre-buried geomagnetic reference point array is arranged, each geomagnetic reference point is composed of a permanent magnet and a stainless steel shell package, and is arranged symmetrically along the longitudinal center line of the tunnel; the inertial measurement unit contains a three-axis gyroscope and an accelerometer; the transmitting antenna of the wireless communication module is installed on the top of the vehicle, and the receiving antenna is located at the central position of the tunnel vault.

[0005] Further, the bracket is provided with an angle adjusting structure, which comprises: a rotating disc fixed at the bottom of the UWB positioning anchor point, a plurality of positioning holes are uniformly arranged on the surface of the rotating disc in the circumferential direction, and the spacing between adjacent positioning holes corresponds to a 10° turning angle of the anchor point; a spring pin is installed at the fixed end of the bracket, and the spring pin is inserted into different positioning holes by pressing the spring pin to realize multi-angle adjustment of the UWB positioning anchor point.

[0006] Further, the surface of the bracket is covered with a shockproof rubber sleeve.

[0007] Furthermore, the geomagnetic reference point array is composed of multiple reference units symmetrically arranged along the longitudinal centerline of the tunnel. The reference unit includes the following structure: a permanent magnet group, consisting of three axially magnetized cylindrical neodymium iron boron permanent magnets coaxially stacked in the vertical direction, with adjacent permanent magnets bonded and fixed by opposite poles of the N and S poles to form a directionally identifiable strong magnetic signal source; and a composite encapsulation shell, including an inner protective shell and an outer buffer layer. The inner protective shell is a cylindrical shell made of stainless steel, and the permanent magnet group is disposed inside the inner protective shell. The outer buffer layer is an epoxy resin layer.

[0008] Furthermore, the reference unit also includes an anchoring flange, which is an annular boss extending horizontally outward from the bottom outer edge of the inner protective shell, with four bolt holes evenly distributed circumferentially on the surface of the boss.

[0009] Furthermore, it also includes a vehicle-mounted transmitting antenna assembly, which includes a vertical support rod, the bottom of which is fixed to the top plane of the vehicle by a flange, and the transmitting antenna is fixed at the top.

[0010] Furthermore, it also includes a tunnel receiving antenna assembly, which comprises a distributed receiving array and an arch-top fixing base; the distributed receiving array consists of three receiving antennas arranged in an equilateral triangle in the central area of ​​the tunnel arch; the arch-top fixing base includes a pre-embedded steel plate and a quick-release antenna holder, the pre-embedded steel plate is embedded in the concrete layer of the tunnel arch, and threaded columns are welded to the surface of the steel plate; the quick-release antenna holder consists of a lower rotating sleeve and an upper U-shaped clamp, the rotating sleeve is screwed and fixed to the threaded column, and the inner wall of the U-shaped clamp is fitted to the receiving antenna rod and locked by a butterfly bolt.

[0011] This utility model has at least the following beneficial effects:

[0012] This utility model's positioning device includes UWB positioning, geomagnetic reference points, and inertial measurement, which can help overcome the positioning failure problem caused by the lack of satellite signals in tunnels. Through the adjustable angle bracket design of the UWB anchor points on the tunnel sidewall, it adapts to curved sections and slopes of the tunnel, expanding the signal coverage area. Combined with the ground-embedded axially stacked geomagnetic reference point array, it provides highly recognizable magnetic field characteristics, thus helping to improve positioning effectiveness.

[0013] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of an angle adjustment structure according to an embodiment of the present invention;

[0015] Figure 2 This is a schematic diagram of the structure of a reference unit according to an embodiment of the present invention;

[0016] Figure 3 This is a schematic diagram of the structure of an arch fixing base according to an embodiment of the present invention;

[0017] Figure 4 This is a framework diagram of one embodiment of the present utility model. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0019] It should be understood that terms such as "having," "comprising," and "including" used in the embodiments of this application do not exclude the presence or addition of one or more other elements or combinations thereof. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. When an element is referred to as "fixed to" or "set on" another element, it can be directly on the other element or may have an intervening element present. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element through an intervening element. Descriptions involving "first," "second," etc., in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0020] It should be noted that the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

[0021] like Figure 4As shown, embodiments of this application provide a tunnel vehicle positioning device, including a UWB positioning module, a three-axis geomagnetic sensor, an inertial measurement unit, and a wireless communication module installed on the vehicle chassis; the UWB positioning module includes a transceiver antenna, and UWB positioning anchor points are arranged at intervals on the tunnel sidewall, each UWB positioning anchor point being fixed on a bracket 1 on the tunnel sidewall; a geomagnetic reference point array is pre-embedded in the tunnel ground, each geomagnetic reference point being composed of a permanent magnet 6 encapsulated in a stainless steel shell, and symmetrically arranged at intervals along the longitudinal centerline of the tunnel; the inertial measurement unit includes a three-axis gyroscope and an accelerometer; the transmitting antenna of the wireless communication module is installed on the top of the vehicle, and the receiving antenna is located at the center of the tunnel arch.

[0022] For example, the UWB positioning module includes a transceiver antenna, which can be a Decawave DW1000 chipset or an NXP SR040 module. UWB positioning anchor points are spaced apart on the tunnel sidewall, with the spacing between anchor points set to 10-15 meters or 15-20 meters, adjusted according to the tunnel's radius of curvature. Each UWB positioning anchor point is fixed to the tunnel sidewall by a bracket 1, which can be made of aluminum alloy or stainless steel. The surface of the bracket 1 is covered with a shock-absorbing rubber sleeve, the rubber material of which can be styrene-butadiene rubber or silicone, with a thickness of 3-5 mm. The bracket 1 is installed 0.8-1.2 meters above the maintenance platform on the tunnel sidewall and is fixed using expansion bolts.

[0023] For example, the geomagnetic reference point array consists of permanent magnets 6 encapsulated in a stainless steel shell. The permanent magnets 6 can be neodymium iron boron (N52 grade) or samarium cobalt magnets, with a single magnet having a diameter of 30 mm or 40 mm and a height of 10-15 mm. The inner protective shell 4 of the stainless steel shell has a thickness of 1-1.5 mm and can be made of 304 or 316L stainless steel. The geomagnetic reference points are symmetrically arranged along the longitudinal centerline of the tunnel, and the spacing between adjacent reference points can be set to 5 meters or 8 meters.

[0024] For example, the inertial measurement unit includes a three-axis gyroscope and an accelerometer, and can be an MPU-6050 or BMI160 sensor module, with a sampling frequency set to 100-200Hz. The transmitting antenna of the wireless communication module is mounted on the roof of the vehicle, and the antenna can be a Taoglas AA.105 or ProAnt 4208 model with a gain of 3-5dBi.

[0025] While the vehicle is in motion, the UWB positioning module acquires distance data between the vehicle and multiple anchor points through bidirectional ranging via sidewall anchor points; a three-axis geomagnetic sensor detects the vertical magnetic field strength and direction of six ground permanent magnet reference points in real time; and an inertial measurement unit synchronously collects the vehicle's three-axis angular velocity and acceleration. The UWB ranging data and the dead reckoning results from the inertial unit are input into an extended Kalman filter (EKF), and communication delays are eliminated through timestamp alignment; based on the peak magnetic field strength and direction characteristics captured by the geomagnetic sensor, the system matches the data with a pre-stored reference point magnetic field database to determine the vehicle's current position. This embodiment's positioning device, including UWB positioning, geomagnetic reference points, and inertial measurement, helps overcome the positioning failure problem caused by the lack of satellite signals within tunnels.

[0026] like Figure 1 As shown, in another embodiment, the bracket 1 is provided with an angle adjustment structure, which includes: a rotating disk 2, fixed to the bottom of the UWB positioning anchor point 302, the surface of the rotating disk 2 having a plurality of positioning holes 301 evenly opened along the circumferential direction, the spacing between adjacent positioning holes 301 corresponding to a 10° turning angle of the anchor point; a spring pin 3, installed on the fixed end of the bracket 1, the UWB positioning anchor point 302 can be adjusted to multiple angles by pressing the spring pin 3 to insert the spring pin 3 into different positioning holes 301; the surface of the bracket 1 is covered with a shockproof rubber sleeve.

[0027] For example, the rotating disk 2 can be fixed to the bottom of the UWB positioning anchor point 302, and the number of positioning holes 301 evenly opened along the circumferential direction on its surface can be 36, with the spacing between adjacent positioning holes 301 being a 10° turning angle. The spring pin 3 can be installed on the fixed end of the bracket 1, and its spring force threshold can be set to 5-8 Newtons. The material of the spring pin 3 can be spring steel or 304 stainless steel.

[0028] The rotating disk 2 can be made of 6061 aluminum alloy or 316 stainless steel, with a thickness of 8-12 mm. During assembly, the rotating disk 2 is fixed to the bottom of the UWB anchor point with bolts of M4 or M6 size and a thread depth of 5-8 mm. The fixed end of the bracket 1 is 1.5-2 meters above the tunnel sidewall ground, and is installed using expansion bolts or chemical anchors.

[0029] During operation, press the spring pin 3 to disengage it from the current positioning hole 301. Manually rotate the UWB anchor point to the target angle and release the spring pin 3. The pin will then insert into the corresponding positioning hole 301 to complete the fixation. The scale markings on the rotating disk 2 can be aligned with the positioning hole 301 to assist in angle calibration. This embodiment uses mechanical angle adjustment to adapt to different tunnel curvatures and improve the uniformity of UWB signal coverage.

[0030] A shock-absorbing rubber sleeve can be applied to the surface of bracket 1. The rubber material can be styrene-butadiene rubber or silicone, with a thickness of 3-5 mm. The rubber sleeve can be fixed to bracket 1 by heat pressing or by sleeve connection. When sleeved, the inner diameter of the rubber sleeve is 1-2 mm smaller than the outer diameter of bracket 1 to achieve an interference fit. The rubber sleeve covers the entire length of bracket 1, extending 5-10 mm beyond the outer side of the rotating disk 2 and the side wall fixing end. Vibrations generated by vehicle traffic are transmitted to the rubber sleeve through bracket 1. The rubber sleeve absorbs high-frequency vibration energy through deformation, reducing the displacement of the UWB anchor point. Drainage grooves, 2-3 mm wide, can be provided on the surface of the rubber sleeve to prevent water accumulation and corrosion.

[0031] like Figure 2 As shown, in another embodiment, the geomagnetic reference point array is composed of multiple reference units symmetrically arranged along the longitudinal centerline of the tunnel. The reference unit includes the following structure: 6 sets of permanent magnets, consisting of three axially magnetized cylindrical neodymium iron boron permanent magnets 6 coaxially stacked in the vertical direction, with adjacent permanent magnets 6 bonded and fixed by opposite poles of the N and S poles to form a directionally identifiable strong magnetic signal source; a composite encapsulation shell, including an inner protective shell 4 and an outer buffer layer 5. The inner protective shell 4 is a cylindrical shell made of stainless steel, and the set of permanent magnets 6 is disposed inside the inner protective shell 4. The outer buffer layer 5 is an epoxy resin layer; the reference unit also includes an anchoring flange 401, which is an annular boss extending horizontally outward from the bottom outer edge of the inner protective shell 4, with four bolt holes evenly distributed circumferentially on the surface of the boss.

[0032] For example, the permanent magnet group 6 consists of three axially magnetized cylindrical neodymium iron boron permanent magnets 6. The diameter of a single magnet can be selected as 30 mm or 40 mm, and the height can be selected as 10 mm or 15 mm. The axial magnetization direction of the magnets can be perpendicular to the ground. Adjacent permanent magnets 6 are bonded and fixed together by opposite polarities (NS poles). The adhesive can be epoxy structural adhesive or acrylic adhesive, and the curing time threshold is set to 30-60 minutes. The total height of the magnet group can be controlled within the range of 30-45 mm.

[0033] During assembly, the magnet assemblies are coaxially stacked vertically, with the N pole of the bottom magnet facing down, the S pole of the middle magnet facing down, and the N pole of the top magnet facing up, forming a vertical magnetic field strength gradient. The coaxiality deviation of the magnet assembly is controlled within ±0.5 mm and can be calibrated using a laser alignment instrument. The triaxial geomagnetic sensor on the vehicle chassis identifies the reference point position by detecting the vertical magnetic field strength and polarity distribution of the magnet assemblies. The stacking design of the magnet assemblies enables the magnetic field signal intensity at a height of 1 meter to reach 50-80 μT, which is higher than the background magnetic field of the tunnel. The vertical magnetic field characteristics are enhanced by axially opposite-pole stacking, improving the identifiability of the geomagnetic reference point.

[0034] For example, the composite encapsulation shell includes an inner protective shell 4 and an outer buffer layer 5. The inner protective shell 4 can be made of 304 stainless steel or 316L stainless steel, with a thickness of 1.0-1.5 mm, a cylindrical shell diameter of 35-45 mm, and a height of 35-50 mm. The epoxy resin layer of the outer buffer layer 5 can be made of two-component epoxy adhesive, with a cured thickness of 2-3 mm and a Shore D hardness of 70-80.

[0035] During assembly, six sets of permanent magnets are placed inside the inner protective shell 4, with a 2-3 mm gap between the bottom and the bottom surface of the shell, and the gap is filled with silicone buffer pads. The outer epoxy resin is cast and molded to encase the inner shell, and after curing, the surface is polished to be flush with the tunnel floor. A 1-2 mm thick polycarbonate protective cover can be added to the top of the shell. During operation, the stainless steel inner shell isolates it from groundwater corrosion, while the epoxy buffer layer absorbs the impact of vehicle crushing, achieving a peak pressure withstand threshold of 20-30 MPa. This double-layer protective structure balances sealing and pressure resistance, extending the service life of the reference points.

[0036] The anchoring flange 401 is an annular boss that extends horizontally from the bottom outer edge of the inner protective shell 4. The outer diameter of the boss can be set to 60-80 mm, and the width is 10-15 mm. Four bolt holes are evenly distributed around the circumference on the surface of the boss. The hole diameter can be selected as 8 mm or 10 mm, and the hole spacing is 50-60 mm.

[0037] During assembly, the reference unit is fixed to the pre-embedded base on the tunnel floor using M8 or M10 chemical anchors, with the anchor torque threshold set at 15-20 N·m. A 1-2 mm thick nitrile rubber pad can be inserted between the lower surface of the boss and the tunnel floor to reduce vibration transmission. The reference unit is embedded at a depth of 40-50 mm, and the height difference between its upper surface and the ground is controlled within ±0.5 mm. During operation, the anchor flange 401 resists the shear force of vehicle rolling through the friction between the bolt tension and the concrete substrate, with a pull-out force threshold ≥5 kN. Multi-point bolt fixing ensures the positional stability of the reference unit and prevents displacement after long-term use.

[0038] In another embodiment, a vehicle-mounted transmitting antenna assembly is also included, comprising a vertical support rod whose bottom is fixed to the top plane of the vehicle via a flange, and whose upper end is fixed to the transmitting antenna.

[0039] For example, the vertical support rod can be made of 6061 aluminum alloy or 304 stainless steel, with an outer diameter of 25-40 mm and a wall thickness of 2-3 mm. The flange can be round or square, with a diameter or side length of 80-120 mm. The flange can have 4 or 6 bolt holes, and the bolts can be M6 or M8. The support rod height can be 0.5-0.8 meters, and its bottom is fixed to the flange by welding or threading.

[0040] During assembly, the flange is fixed to the vehicle's roof surface using expansion bolts or self-tapping screws, with bolt spacing set to 50-70 mm. The installation position on the vehicle's roof surface can be selected at the center or rear of the roof, at least 200 mm from the edge of the roof to avoid interfering with other equipment. The perpendicularity deviation of the support rod to the roof surface should be controlled within ±2°, and can be calibrated using a level.

[0041] During operation, vibrations generated by vehicle movement are transmitted to the support rod via the flange. The rigid structure of the support rod reduces antenna sway. A 1-2 mm thick nitrile rubber pad can be added to the contact surface between the flange and the vehicle roof to further reduce vibration transmission. This rigid support structure ensures antenna attitude stability and reduces signal pointing deviation.

[0042] The transmitting antenna can be fixed to the upper end of the support rod, either by threaded connection or clamp locking. For threaded connection, the top of the support rod can be machined with an M16 or M20 external thread to match the internal thread at the bottom of the antenna. For clamp locking, the clamp material can be 304 stainless steel or aluminum alloy, with a width of 20-30 mm, and the tightening bolt torque threshold set to 3-5 N·m.

[0043] like Figure 3 As shown, in another embodiment, a tunnel receiving antenna assembly is also included, comprising a distributed receiving array and a dome-shaped fixing base; the distributed receiving array consists of three receiving antennas arranged in an equilateral triangle in the central area of ​​the tunnel dome; the dome-shaped fixing base includes a pre-embedded steel plate 7 and a quick-release antenna holder, the pre-embedded steel plate 7 is embedded in the concrete layer of the tunnel dome, and threaded columns 8 are welded to the surface of the steel plate; the quick-release antenna holder consists of a lower rotating sleeve 9 and an upper U-shaped clamp 10, the rotating sleeve 9 is screwed and fixed to the threaded column 8, and the inner wall of the U-shaped clamp 10 is fitted to the receiving antenna rod and locked by a butterfly bolt 1001.

[0044] For example, the three receiving antennas can be arranged in an equilateral triangle in the central area of ​​the tunnel arch. The side length of the equilateral triangle can be set to 1.2-1.8 meters or 2.0-2.5 meters, depending on the tunnel cross-sectional dimensions. The receiving antennas can be UWB omnidirectional antennas, such as Decawave DWM1001 or NXP SR040, with a gain range of 3-5 dBi. The antenna mast diameter can be set to 10-15 mm, and the material can be 6061 aluminum alloy or 304 stainless steel.

[0045] During assembly, the center points of the three antennas are located along the longitudinal centerline of the tunnel arch, with the spacing error between adjacent antennas controlled within ±50 mm. The antenna radiation direction can be adjusted to vertically downwards, forming a direct line-of-sight link with the vehicle-mounted transmitting antenna. The bottom of the antenna mast is 0.3-0.5 meters above the concrete surface of the arch and is fixed using clamps. During operation, the equilateral triangle layout reduces multipath interference through spatial diversity reception, resulting in better signal coverage uniformity than linear arrays. In the event of a single antenna failure, the remaining two antennas can still maintain basic communication functions. This improves signal reception stability and adapts to the curved structure of the tunnel arch.

[0046] The embedded steel plate 7 can be made of Q235 carbon steel or 304 stainless steel, with a thickness of 8-12 mm and dimensions of 150×150 mm or 200×200 mm. The threaded posts 8 welded to the surface of the steel plate can be made of M12 or M16 stainless steel threaded rods, with a length of 80-120 mm and a welding strength threshold ≥200 MPa. The steel plate is embedded to a depth of 50-80 mm into the tunnel arch concrete layer, with a concrete grade not lower than C30. During assembly, the steel plate is pre-embedded during the tunnel lining construction stage, with the threaded posts 8 extending vertically upwards 10-15 mm beyond the concrete surface. Adjacent steel plates are arranged at intervals of 5-8 meters along the tunnel's longitudinal direction, with the transverse centerline coinciding with the tunnel's longitudinal centerline. The edges of the steel plates in contact with the concrete can be coated with epoxy anti-rust paint, with a film thickness of 50-80 micrometers.

[0047] The inner diameter of the rotating sleeve 9 of the quick-release antenna holder can be set to 12.5 mm or 16.5 mm, with a clearance tolerance of H7 / g6 between it and the outer diameter of the threaded column 8. The opening width of the U-clamp 10 can be selected from 15-20 mm, and the contact surface of the inner wall that fits against the antenna mast can be machined with a V-shaped anti-slip groove with a groove depth of 0.5-1.0 mm. The tightening torque threshold of the wing bolt 1001 can be set to 1.5-2.0 N·m, and the bolt material can be selected from 4.8 grade or 8.8 grade carbon steel. During assembly, the rotating sleeve 9 is screwed into the threaded column 8 to the bottom, and pre-tightened using a wrench along the hexagonal edges (19 mm or 22 mm width across sides) on the outer wall of the sleeve. After the U-clamp 10 covers the antenna mast, the wing bolt 1001 is tightened to the set torque to prevent relative slippage between the antenna mast and the holder. The antenna elevation angle adjustment range is ±15°, which can be finely adjusted using the annular scale markings on the rotating sleeve 9. During operation, the antenna can be quickly removed simply by loosening the wing bolt 1001 and rotating the sleeve 9, reducing maintenance time by more than 70% compared to traditional welding methods. This embodiment enables rapid antenna installation and fine-tuning of the angle, reducing maintenance complexity.

[0048] The number of devices and processing scale described herein are for the purpose of simplifying the description of this utility model. Applications, modifications, and variations of the tunnel vehicle positioning device of this utility model will be readily apparent to those skilled in the art.

[0049] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A tunnel vehicle positioning device, characterized in that, It includes a UWB positioning module, a three-axis geomagnetic sensor, an inertial measurement unit, and a wireless communication module installed on the vehicle chassis; The UWB positioning module includes a transceiver antenna, and UWB positioning anchor points are arranged at intervals on the tunnel sidewall, with each UWB positioning anchor point fixed on a bracket on the tunnel sidewall. The tunnel surface is pre-embedded with a geomagnetic reference point array. Each geomagnetic reference point is composed of a permanent magnet and a stainless steel shell, and is symmetrically arranged at intervals along the longitudinal centerline of the tunnel. The inertial measurement unit includes a three-axis gyroscope and an accelerometer; The transmitting antenna of the wireless communication module is mounted on the top of the vehicle, and the receiving antenna is located in the center of the tunnel arch.

2. The tunnel vehicle positioning device as described in claim 1, characterized in that, The bracket is provided with an angle adjustment structure, the angle adjustment structure including: A rotating disk is fixed at the bottom of the UWB positioning anchor point. Multiple positioning holes are evenly opened on the surface of the rotating disk along the circumferential direction, and the spacing between adjacent positioning holes corresponds to a 10° turning angle of the anchor point. A spring pin is installed on the fixed end of the bracket. By pressing the spring pin, the UWB positioning anchor point can be adjusted at multiple angles by inserting it into different positioning holes.

3. The tunnel vehicle positioning device as described in claim 2, characterized in that, The surface of the bracket is covered with a shock-absorbing rubber sleeve.

4. The tunnel vehicle positioning device as described in claim 1, characterized in that, The geomagnetic reference point array is composed of multiple reference units symmetrically arranged along the longitudinal centerline of the tunnel. The reference unit includes the following structure: The permanent magnet assembly consists of three axially magnetized cylindrical neodymium iron boron permanent magnets stacked coaxially in the vertical direction. Adjacent permanent magnets are bonded and fixed together by opposite poles of the N and S poles, forming a strong magnetic signal source with identifiable direction. The composite encapsulation shell includes an inner protective shell and an outer buffer layer. The inner protective shell is a cylindrical shell made of stainless steel. The permanent magnet assembly is disposed inside the inner protective shell. The outer buffer layer is an epoxy resin layer.

5. The tunnel vehicle positioning device as described in claim 4, characterized in that, The reference unit also includes an anchoring flange, which is an annular boss that extends horizontally outward from the bottom outer edge of the inner protective shell, and four bolt holes are evenly distributed circumferentially on the surface of the boss.

6. The tunnel vehicle positioning device as described in claim 1, characterized in that, It also includes a vehicle-mounted transmitting antenna assembly, which includes a vertical support rod, the bottom of which is fixed to the top plane of the vehicle by a flange, and the transmitting antenna is fixed at the top.

7. The tunnel vehicle positioning device as described in claim 6, characterized in that, It also includes a tunnel receiving antenna assembly, which comprises a distributed receiving array and a vaulted fixed base; The distributed receiving array consists of three receiving antennas arranged in an equilateral triangle in the central area of ​​the tunnel arch. The arch fixing base includes a pre-embedded steel plate and a quick-release antenna holder. The pre-embedded steel plate is embedded in the concrete layer of the tunnel arch, and a threaded column is welded to the surface of the steel plate. The quick-release antenna holder consists of a lower rotating sleeve and an upper U-shaped clamp. The rotating sleeve is screwed and fixed to the threaded column, and the inner wall of the U-shaped clamp is attached to the receiving antenna rod and locked by a butterfly bolt.

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