A precise positioning method of a coal mine underground monorail crane based on wireless communication

Abstract

This invention discloses a precise positioning method for a monorail hoist in a coal mine based on wireless communication, relating to the field of monorail hoist positioning technology. The method includes: installing a positioning base station and a wireless communication terminal on the monorail hoist; installing several positioning cards on the mine roadway wall; establishing a GIS coordinate system within a data center on the ground; accurately measuring the installation positions of the positioning cards and marking them in the GIS coordinate system; measuring the distance between the positioning base station and two positioning cards; calculating the distance between the two positioning cards using their coordinates; and calculating a unique coordinate value based on the distance measured between the positioning base station and the two positioning cards using the cosine theorem and azimuth formula to achieve positioning. This method solves the problem of high construction costs associated with monorail hoist positioning, which typically requires adding a new positioning base station to provide a new positioning frequency band to avoid co-channel interference. Since positioning base stations often have high power consumption, each base station also requires an additional power supply device.

Description

Technical Field

[0001] This invention relates to the field of monorail positioning technology, specifically a precise positioning method for a monorail in a coal mine based on wireless communication. Background Technology

[0002] A monorail is an auxiliary transportation device used underground, primarily for transporting personnel and materials. It has high traction and runs along steel rails fixed to the top of coal mine roadways, its speed unaffected by the harsh road conditions, making it widely used underground. Since GPS signals cannot be used in the mine roadways where monorails operate, UWB positioning technology is generally employed for precise control of the monorail.

[0003] Currently, UWB positioning uses a combination of base stations and positioning cards. The base station serves as the positioning coordinate point, while personnel wearing positioning cards or having them installed on mobile devices act as the target to be located. In scenarios where precise personnel positioning has already been established, from the perspectives of safety management and unmanned intelligent operation, monorail-type equipment requires a shorter positioning cycle. If the same wireless frequency band is used for both personnel positioning and positioning, co-channel interference and signal submersion can easily lead to failures in both monorail positioning and personnel positioning. To solve the co-channel interference problem, monorail positioning typically involves adding new base stations to provide a new positioning frequency band. Since base stations often have high power consumption, each base station also requires an additional power supply device, resulting in high construction costs. Summary of the Invention

[0004] The purpose of this invention is to provide a precise positioning method for monorail cranes in coal mines based on wireless communication. This method solves the problem that, in order to avoid co-channel interference, monorail crane positioning usually requires the addition of new positioning base stations to provide new positioning frequency bands. Since positioning base stations often have high power consumption, each base station also needs to be equipped with an additional power supply device, resulting in high construction costs.

[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: A precise positioning method for a monorail crane in a coal mine based on wireless communication, characterized by comprising: A positioning base station and a wireless communication terminal are installed on the monorail gantry. The wireless communication terminal is connected to the signal of the wireless communication base station on the ground. Several positioning cards are installed on the walls of the mine roadway. The ground-based data center station system establishes a GIS coordinate system, and the GIS coordinate system establishes the tunnel area and the continuous movement trajectory of the monorail gantry. Accurately measure the installation location of the positioning card and mark the installation location of the positioning card in the GIS coordinate system; The positioning base station and two positioning cards complete the distance measurement. The distance measurement result is uploaded to the data center station via wireless communication. At the same time, the positioning base station also synchronizes with the system time via wireless communication. The distance between the two positioning cards is calculated by measuring their coordinates. Based on the distance measured between the positioning base station and the two positioning cards, a unique coordinate value is calculated using the law of cosines and the azimuth formula to achieve positioning.

[0006] Preferably, the positioning frequency band of the positioning base station is set to be different from the general personnel precise positioning frequency band underground.

[0007] Preferably, the positioning base station is powered by a monorail.

[0008] Preferably, the plurality of positioning clips are installed at equal intervals on the walls of the mine roadway.

[0009] Preferably, the wireless communication base station is communicatively connected to the data center station.

[0010] Preferably, when measuring distance, the distance values ​​of the two most adjacent positioning cards are selected as the calculation factors, and each selected distance value must be completed within the same positioning cycle.

[0011] Preferably, the positioning base station and the positioning card complete the ranging via TOF.

[0012] Preferably, when calculating the coordinates, assume the coordinates of the positioning base station are A(x, y), the coordinates of the two positioning cards are known to be represented as B(x1, y1) and C(x2, y2), and the distance between points A and B is d1, the distance between points B and C is d2, and the distance between points A and C is d3. Let ∠ABC be... According to the Law of Cosines, we have: ; Let the angle between line BC and the y-axis be... According to the universal azimuth formula, we have: ; Where ΔX = x² - x₁; ΔY = y² - y₁, ΔY ≠ 0, if ΔY = 0, then ΔY = 1. -10 ; sign(ΔY) is the sign function, 1 for ΔY > 0, and -1 for ΔY < 0; Let the azimuth angle of line AB be... ,have: ; In a Cartesian coordinate system, we have: ; Then, the coordinate values ​​of the two points A can be calculated and obtained. The coordinate values ​​are then input into the GIS coordinate system. In the coordinate system, the coordinate range of the tunnel, the previous coordinate value, and the time interval between the two coordinate values ​​are combined to complete the coordinate uniqueness determination.

[0013] The present invention has the following beneficial effects: This invention achieves precise positioning of a monorail gantry crane by installing a positioning base station on the monorail crane, installing positioning cards on the walls of the mine roadway, and using wireless communication and data center station participation in calculations. This allows for precise positioning of the monorail crane in a different operating frequency band than a personnel precision positioning system. Furthermore, since the construction primarily involves deploying low-cost positioning cards, only a small number of high-cost positioning base stations and power supply equipment need to be installed, thereby significantly reducing the construction cost of precise positioning of monorail cranes in independent frequency bands.

[0014] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the GIS coordinate system of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] Currently, UWB positioning typically employs a combination of base stations and positioning cards. The base station serves as the positioning coordinate point, while personnel wearing positioning cards or having them installed on mobile devices act as the target being located. In underground coal mines, UWB is used for "personnel and vehicle positioning" to prevent collisions. From a safety management and unmanned intelligent operation perspective, monorail cranes require shorter positioning cycles. If the same wireless frequency band is used for personnel positioning, co-channel interference and signal loss can easily occur. In scenarios where precise personnel positioning has already been established, to address co-channel interference, monorail crane positioning usually involves adding new base stations or adding positioning modules to existing personnel positioning base stations to provide a new positioning frequency band. Simultaneously, the monorail crane positioning card is set to the new positioning frequency band. Due to the specific requirements of coal mine products for coal mine safety certification and explosion-proof certification, additional wireless transmitters are not permitted in the equipment. Therefore, adding new base stations is more common. Since base stations often have high power consumption, each base station requires an additional power supply, resulting in high construction costs that are often prohibitive for coal mining companies.

[0020] To resolve the above issues, please refer to [link / reference]. Figure 1 As shown, this invention is a precise positioning method for a monorail crane in a coal mine based on wireless communication, comprising: A positioning base station and a wireless communication terminal are installed on the monorail gantry. The wireless communication terminal is connected to the signal of the wireless communication base station on the ground. Several positioning cards are installed on the walls of the mine roadway. The ground-based data center station system establishes a GIS coordinate system, and the GIS coordinate system establishes the tunnel area and the continuous movement trajectory of the monorail gantry. Accurately measure the installation location of the positioning card and mark the installation location of the positioning card in the GIS coordinate system; The positioning base station and two positioning cards complete the distance measurement. The distance measurement result is uploaded to the data center station via wireless communication. At the same time, the positioning base station also synchronizes with the system time via wireless communication. The distance between the two positioning cards is calculated by measuring their coordinates. Based on the distance measured between the positioning base station and the two positioning cards, a unique coordinate value is calculated using the law of cosines and the azimuth formula to achieve positioning.

[0021] Furthermore, the positioning frequency band of the positioning base station on the monorail is set to be different from the general personnel precise positioning frequency band underground. Specifically, the tags worn by personnel are small and usually located on the shoulder or on the safety helmet, away from metal. UWB signals can propagate relatively smoothly in the tunnel space, while the monorail is essentially a large metal structure suspended on an I-beam track. When the UWB antenna is installed on the locomotive, the huge metal body (especially the I-beam track) will strongly block and reflect electromagnetic waves. If the same high-frequency band as personnel positioning (such as 4.0 GHz) is used, the path loss of the signal when reflected from the metal surface increases sharply, and it is easy to form severe multipath interference, resulting in extremely unstable ranging. Therefore, two different positioning frequency bands are used for positioning.

[0022] Furthermore, since monorails are mobile devices that travel on tracks hundreds or even thousands of meters long, they cannot be powered by a cable like fixed base stations. Instead, monorails carry large-capacity battery packs (lithium or lead-acid batteries) or diesel-powered hydraulic systems, directly powering the positioning base stations.

[0023] Furthermore, the positioning cards are installed at equal intervals on the walls of the mine roadway. Based on the attenuation law of UWB signals in the roadway, signal blind spots are eliminated, positioning accuracy is guaranteed, equipment redundancy and waste are avoided, and the standardized spacing facilitates construction design, fault diagnosis and spare parts management.

[0024] Furthermore, the wireless communication base station is communicatively connected to the data center station, transmitting the data from the wireless communication terminal to the data center station for data processing and computation.

[0025] Furthermore, during ranging, the ranging values ​​of the two closest positioning cards are preferentially selected as calculation factors. The coordinates of the two closest positioning cards determine the only possible range of the positioning base station coordinates. The direct path signal of the closest positioning card is the strongest and the first wave is the easiest to identify. Selecting them can naturally suppress non-line-of-sight errors caused by multipath reflection or signal attenuation of distant positioning cards. Moreover, each ranging value must be selected within the same positioning cycle to ensure that all ranging values ​​correspond to the target position at the same time.

[0026] Furthermore, the positioning base station and positioning card complete the distance measurement via Time-of-Flight (TOF). The essence of TOF is to measure the round-trip time of radio waves between devices, and calculate the distance using the speed of electromagnetic wave propagation (speed of light c≈3×10⁸ m / sc≈3×10⁸ m / s). The basic formula is:

[0027] Where d represents the distance to be measured, and c represents the speed of light. This is the round-trip time of light.

[0028] Furthermore, when calculating coordinates, such as Figure 2 As shown, assume the coordinates of the positioning base station on the monorail are A(x, y). The coordinates of the two positioning cards closest to the base station on the inner wall of the tunnel are denoted as B(x1, y1) and C(x2, y2), respectively. Measurements show that the distance between points A and B is d1, the distance between points B and C is d2, and the distance between points A and C is d3. Let ∠ABC be... According to the Law of Cosines, we have:

[0029] Obtained through the inverse cosine function :

[0030] Let the angle between line BC and the y-axis be... According to the universal azimuth formula, we have:

[0031] Where ΔX = x² - x₁; ΔY = y² - y₁, ΔY ≠ 0, if ΔY = 0, then ΔY = 1. -10 ; sign(ΔY) is the sign function, 1 for ΔY > 0, and -1 for ΔY < 0; Let the azimuth angle of line AB be... ,have:

[0032] In a Cartesian coordinate system, we have:

[0033] Using the formula above, the x and y values ​​can be calculated to obtain the coordinates of two points A. The coordinates are then input into the GIS coordinate system. By combining the coordinate range of the tunnel, the previous coordinate value, and the time interval between the two coordinate values ​​in the coordinate system, the uniqueness of the coordinates can be determined.

[0034] For example, given that the track is parallel to the tunnel, the function in the coordinate system is... The positioning coordinates are allowed to deviate by 0.3. Assume the coordinates of the positioning base station on the monorail are A(x, y), and the coordinates of the two positioning cards closest to the base station on the inner wall of the tunnel are known to be B(140.4, 98.03) and C(112.57, 61.31). The table below shows the calculated coordinate values ​​of point A at different locations under the same coordinates of points B and C:

[0035] For example, given that the coordinates of the two positioning cards closest to the positioning base station on the inner wall of the alley are B (140.4, 98.03) and C (112.57, 61.31), in the data set number 1, the distance d2 between point B and point C is 46.07; Then, the distance was measured by the positioning base station and positioning card on the monorail using the TOF method. The distance between point A and point B was measured as d1 = 53.75, and the distance between point A and point C was measured as d2 = 7.71. Next, calculate according to the formula to obtain ∠ABC. value, =0.02; ΔX = x2 - x1 = 112.57 - 140.4 = -27.83, ΔY = y2 - y1 = 61.31 - 98.03 = -34.72, where ΔY < 0, and the sign function sign(ΔY) is -1; The angle between line BC and the y-axis is According to the universal azimuth formula:

[0036] Calculations show that 4.06; When point A is above line BC Calculation =4.04; When point A is below line BC Calculation =4.08; Based on the coordinate system, point A is below line BC. =4.08 Substituted into the subsequent formula:

[0037] We find x = 108.78 and y = 54.6, so the coordinates of point A are A(108.78, 54.6).

[0038] This invention achieves precise positioning of a monorail gantry crane by installing a positioning base station on the monorail crane, installing positioning cards on the walls of the mine roadway, and using wireless communication and data center station participation in calculations. This allows for precise positioning of the monorail crane in a different operating frequency band than a personnel precision positioning system. Furthermore, since the construction primarily involves deploying low-cost positioning cards, only a small number of high-cost positioning base stations and power supply equipment need to be installed, thereby significantly reducing the construction cost of precise positioning of monorail cranes in independent frequency bands.

[0039] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A precise positioning method for a monorail crane in a coal mine based on wireless communication, characterized in that, include: A positioning base station and a wireless communication terminal are installed on the monorail gantry. The wireless communication terminal is connected to the signal of the wireless communication base station on the ground. Several positioning cards are installed on the walls of the mine roadway. The ground-based data center station system establishes a GIS coordinate system, and the GIS coordinate system establishes the tunnel area and the continuous movement trajectory of the monorail gantry. Accurately measure the installation location of the positioning card and mark the installation location of the positioning card in the GIS coordinate system; The positioning base station and two positioning cards complete the distance measurement. The distance measurement result is uploaded to the data center station via wireless communication. At the same time, the positioning base station also synchronizes with the system time via wireless communication. The distance between the two positioning cards is calculated by measuring their coordinates. Based on the distance measured between the positioning base station and the two positioning cards, a unique coordinate value is calculated using the law of cosines and the azimuth formula to achieve positioning.

2. The precise positioning method for a monorail crane in a coal mine based on wireless communication according to claim 1, characterized in that: The positioning frequency band of the positioning base station is set to be different from the general personnel precise positioning frequency band underground.

3. The precise positioning method for a monorail crane in a coal mine based on wireless communication according to claim 1, characterized in that: The positioning base station is powered by a monorail.

4. The precise positioning method for a monorail crane in a coal mine based on wireless communication according to claim 1, characterized in that: The aforementioned positioning cards are installed at equal intervals on the walls of the mine roadways.

5. The precise positioning method for a monorail crane in a coal mine based on wireless communication according to claim 1, characterized in that: The wireless communication base station is connected to the data center station.

6. The precise positioning method for a monorail crane in a coal mine based on wireless communication according to claim 1, characterized in that: When measuring distance, the distance values ​​of the two most adjacent positioning cards are selected as the calculation factors, and each selected distance value must be completed within the same positioning cycle.

7. The precise positioning method for a monorail crane in a coal mine based on wireless communication according to claim 1, characterized in that: The positioning base station and positioning card complete the distance measurement through TOF.

8. The precise positioning method for a monorail crane in a coal mine based on wireless communication according to claim 1, characterized in that: When calculating the coordinates, assume the coordinates of the positioning base station are A(x, y), and the coordinates of the two positioning cards are represented as B(x1, y1) and C(x2, y2), respectively. Furthermore, it is known through measurement that the distance between points A and B is d1, the distance between points B and C is d2, and the distance between points A and C is d3. Let ∠ABC be... According to the Law of Cosines, we have: ； Let the angle between line BC and the y-axis be... According to the universal azimuth formula, we have: ； Where ΔX = x² - x₁; ΔY = y² - y₁, ΔY ≠ 0, if ΔY = 0, then ΔY = 1. -10 ; sign(ΔY) is the sign function, 1 for ΔY > 0, and -1 for ΔY < 0; Let the azimuth angle of line AB be... ,have: ； In a Cartesian coordinate system, we have: ； Then, the coordinate values ​​of the two points A can be calculated and obtained. The coordinate values ​​are then input into the GIS coordinate system. In the coordinate system, the coordinate range of the tunnel, the previous coordinate value, and the time interval between the two coordinate values ​​are combined to complete the coordinate uniqueness determination.

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