A precise positioning method and device for subway construction workers

Abstract

The present invention provides a precise positioning method and device for subway construction workers, relating to the technical field of subway construction worker positioning, so as to precisely position and give early warnings for the unsafe behaviors of subway construction workers. The method includes: obtaining the distances between the positioning tags of construction workers and several positioning base station nodes based on the bilateral two-way ranging method; and obtaining the position range of the positioning tags based on the trilateration algorithm with Kalman filtering according to the distances between the positioning tags and the several positioning base station nodes. The precise positioning device for subway construction workers is applied to the precise positioning method for subway construction workers.

Description

Technical Field

[0001] The present invention relates to the technical field of subway construction worker positioning, and in particular to a subway construction worker precise positioning method and device. Background Art

[0002] With the rapid development of information technology and automation technology, the trend is to use unified information management of subway construction, continue automated construction, and use Internet of Things technology to predict, prevent, and eliminate the occurrence of safety accidents. At the same time, through the analysis of various subway construction accident cases, most of them involve human factors. Therefore, controlling people's "unsafe behavior" is the basis of all safety management work, and the positioning and management of personnel at the subway construction site is the top priority.

[0003] When construction is being carried out in a subway tunnel, it is very dangerous if construction workers climb or sit in unsafe positions; work or stay under hoisted objects; or mistakenly enter or break into dangerous or unauthorized areas. If not notified in time, it is likely to cause an irreversible accident. At this time, it is necessary to accurately locate the subway construction workers and identify unsafe behaviors, and notify the management personnel of the warning information in advance to reduce the chance of accidents. At the same time, accurate location information is also an important information support for post-disaster search and rescue. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method and device for accurately locating subway construction workers, so as to accurately locate and warn of unsafe behaviors of subway construction workers.

[0005] The present invention provides a method for accurately positioning subway construction workers, the method comprising:

[0006] Step 1: Obtain the distance between the construction worker's positioning tag and several positioning base station nodes based on the bilateral two-way ranging method;

[0007] Step 2: According to the distance between the positioning tag and several positioning base station nodes, the location range of the positioning tag is obtained based on the trilateral measurement algorithm with Kalman filtering.

[0008] Preferably, the step 1: obtaining the distance between the construction worker positioning tag and the nodes between several positioning base stations based on the bilateral two-way ranging method includes:

[0009] Step 1.1: The positioning tag transmits two signals continuously, namely the first signal and the second signal;

[0010] Step 1.2: Several positioning base station nodes all receive two signals transmitted by the positioning tag; among the several positioning base station nodes, there is a master fixed node and several slave fixed nodes;

[0011] Step 1.3: After receiving the second signal, the master fixed node delays for a period of time and transmits a third signal to all slave fixed nodes, and at the same time sends the third signal to the positioning tag;

[0012] Step 1.4: After receiving the third signal, the positioning tag delays for a period of time and transmits a fourth signal to the master fixed node;

[0013] Step 1.5: Calculate the distances between the positioning tag and each positioning base station node according to the time when the positioning tag and the positioning base station node send signals and receive signals, and in combination with the distances between the positioning base station nodes themselves.

[0014] Preferably, there are four positioning base station nodes, one of which is the master fixed node, and the other three are the first slave fixed node, the second slave fixed node, and the third slave fixed node respectively;

[0015] The distance calculation formula between the master fixed node and the positioning tag is:

[0016]

[0017] The distance calculation formula between the first slave fixed node and the positioning tag is:

[0018]

[0019] In formula (2),

[0020] The distance calculation formula between the second slave fixed node and the positioning tag is:

[0021]

[0022] In formula (3),

[0023] The distance calculation formula between the third slave fixed node and the positioning tag is:

[0024]

[0025] In formula (4)

[0026] Among them, S A is the distance between the master fixed node and the positioning tag, S B is the distance between the first slave fixed node and the positioning tag, S C is the distance between the second slave fixed node and the positioning tag, S D is the distance between the third slave fixed node and the positioning tag; τ RP′ is the time when the positioning tag receives the third signal, τSP′ The time for the positioning tag to transmit the second signal, τ SP′4 The time for the positioning tag to transmit the fourth signal, τ RP′4 The time for the master fixed node to receive the fourth signal, τ SA3 The time for the master fixed node to transmit the third signal, τ RA2 The time for the master fixed node to receive the second signal, τ RA1 The time for the master fixed node to receive the first signal, τ RB1 The time for the first slave fixed node to receive the first signal, τ RB2 The time for the first slave fixed node to receive the second signal, τ RB3 The time for the first slave fixed node to receive the third signal, τ RC1 The time for the second slave fixed node to receive the first signal, τ RC2 The time for the second slave fixed node to receive the second signal, τ RC3 The time for the second slave fixed node to receive the third signal, τ RD1 The time for the third slave fixed node to receive the first signal, τ RD2 The time for the third slave fixed node to receive the second signal, τ RD3 The time for the third slave fixed node to receive the third signal; C is the speed of light; S AB The distance between the master fixed node and the first slave fixed node, S AC The distance between the master fixed node and the second slave fixed node, S AD The distance between the master fixed node and the third slave fixed node.

[0027] Preferably, step 2: Based on the distances between the positioning tag and several positioning base station nodes, obtain the position range of the positioning tag based on the trilateration algorithm with Kalman filtering, including:

[0028] Step 2.1: Based on the distances between the positioning tag and several positioning base station nodes as the system state vector x k , establish a ranging model:

[0029] x k = Ax k-1 + Bu k-1 + ω; (5)

[0030] Among them, A ∈ R n×n represents the transition matrix between two states, u ∈ Rl represents the controllable input, B ∈ R n×l represents the transition matrix from the control input to the current state, and ω represents the process noise;

[0031] Step 2.2: Ignoring the control input u, we get:

[0032] x k = Ax k-1 + ω; (6)

[0033] Furthermore, the functional relationship between the current state measurement value and the state value is obtained:

[0034] z k = Hx k + ν; (7)

[0035] where k and k - 1 represent the current state and the previous state respectively, x ∈ R n represents the state to be estimated, z ∈ R m represents the actual measurement value, H ∈ R m×n represents the transformation matrix of the actual measurement value of the current state, and v represents the measurement noise;

[0036] Step 2.3: Calculate the Kalman gain:

[0037] K k = P k|k-1 H T (HP k|k-1 H T + R k ) -1 (8)

[0038] where P k|k-1 is the predicted covariance matrix, R k is the observed noise, and H ∈ R m×n represents the transformation matrix between the current state and the actual measurement value;

[0039] Step 2.4: Calculate the noise threshold:

[0040] Δν = ν T (HP k|k-1 H T ) -1 v (9)

[0041] Step 2.5: Judge the noise threshold. If the noise threshold is less than the preset threshold, obtain the position range of the positioning tag.

[0042] Compared with the prior art, a precise positioning method for subway construction workers provided by the present invention has the following beneficial effects: First, the present invention obtains the distances between the positioning tags of construction workers and several positioning base station nodes based on the bilateral two-way ranging method; then, according to the distances between the positioning tags and several positioning base station nodes, the position range of the positioning tags is obtained based on the trilateration algorithm with Kalman filtering. The present invention uses the two-way bilateral ranging method to calculate the distances between the positioning tags and several positioning base station nodes, and measures the distances from the positioning tags to multiple fixed nodes through one two-way bilateral ranging, solving the problem of long time consumption in multiple two-way bilateral rangings. Moreover, the trilateration algorithm with Kalman filtering is used to obtain the position range of the positioning tags, which can effectively improve the positioning accuracy of subway construction workers.

[0043] The present invention also provides a precise positioning device for subway construction workers, which includes:

[0044] A distance measurement module for obtaining the distances between the positioning tags of subway construction workers and several positioning base station nodes based on the bilateral two-way ranging method;

[0045] A filtering and positioning module for obtaining the position range of the positioning tags based on the trilateration algorithm with Kalman filtering according to the distances between the positioning tags and several positioning base station nodes.

[0046] Compared with the prior art, the beneficial effects of the precise positioning device for subway construction workers provided by the present invention are the same as those of the precise positioning method for subway construction workers described in the above technical solution, and will not be elaborated here.

[0047] The present invention also provides an electronic device, including a bus, a transceiver, a memory, a processor, and a computer program stored on the memory and executable on the processor. The transceiver, the memory, and the processor are connected through the bus. When the computer program is executed by the processor, the steps in any one of the above-mentioned precise positioning methods for subway construction workers are implemented.

[0048] Compared with the prior art, the beneficial effects of the electronic device provided by the present invention are the same as those of the precise positioning method for subway construction workers described in the above technical solution, and will not be elaborated here.

[0049] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps in any one of the above-mentioned precise positioning methods for subway construction workers are implemented.

[0050] Compared with the prior art, the beneficial effects of the computer-readable storage medium provided by the present invention are the same as those of the subway construction worker precise positioning method described in the above technical solution, and will not be elaborated here.

[0051] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, provides detailed descriptions as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0053] Figure 1 shows a flowchart of a subway construction worker precise positioning method provided by an embodiment of the present invention;

[0054] Figure 2 shows a structural schematic diagram of a subway construction worker precise positioning device provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more, unless otherwise specifically defined.

[0056] The "a plurality of" mentioned in this embodiment refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, or B exists alone. Words such as "exemplary" or "for example" are used to indicate examples, illustrations, or explanations, aiming to present relevant concepts in a specific manner and should not be construed as being more preferred or having more advantages than other embodiments or design solutions.

[0057] To address the above technical problems, an embodiment of the present invention provides a subway construction worker precise positioning method. Figure 1 shows a flowchart of a subway construction worker precise positioning method provided by an embodiment of the present invention. As Figure 1 shown, the method includes:

[0058] Step 1: Obtain the distances between the positioning tags of construction workers and several positioning base station nodes based on the bilateral two-way ranging method.

[0059] It should be noted that the construction workers in the subway carry positioning tags on their bodies or helmets, and signal transmission is carried out between the positioning tags and several surrounding positioning base station nodes.

[0060] The said Step 1: Obtain the distances between the positioning tags of construction workers and the nodes between several positioning base stations based on the bilateral two-way ranging method, including:

[0061] Step 1.1: The positioning tag continuously emits two signals, namely the first signal and the second signal.

[0062] Step 1.2: Several positioning base station nodes all receive the two signals emitted by the positioning tag; among the several positioning base station nodes, there is a main fixed node and several slave fixed nodes.

[0063] Step 1.3: After receiving the second signal, the main fixed node delays for a period of time and emits a third signal to all slave fixed nodes, and at the same time sends the third signal to the positioning tag.

[0064] Step 1.4: After receiving the third signal, the positioning tag delays for a period of time and emits a fourth signal to the main fixed node.

[0065] Step 1.5: Calculate the distances between the positioning tag and each positioning base station node according to the time when the positioning tag and the positioning base station node send signals and receive signals, and then combine the distances between the positioning base station nodes themselves.

[0066] Specifically, assume that there are four positioning base station nodes, one of which is the main fixed node, and the other three are the first slave fixed node, the second slave fixed node, and the third slave fixed node respectively.

[0067] The distance calculation formula between the main fixed node and the positioning tag is:

[0068]

[0069] The distance calculation formula between the first slave fixed node and the positioning tag is:

[0070]

[0071] In formula (2),

[0072] The distance calculation formula between the second slave fixed node and the positioning tag is:

[0073]

[0074] In Equation (3),

[0075] The distance calculation formula between the third slave fixed node and the positioning label is:

[0076]

[0077] In Equation (4)

[0078] where S A is the distance between the main fixed node and the positioning label, S B is the distance between the first slave fixed node and the positioning label, S C is the distance between the second slave fixed node and the positioning label, S D is the distance between the third slave fixed node and the positioning label; τ RP′ is the time when the positioning label receives the third signal, τ SP′ is the time when the positioning label transmits the second signal, τ SP′4 is the time when the positioning label transmits the fourth signal, τ RP′4 is the time when the main fixed node receives the fourth signal, τ SA3 is the time when the main fixed node transmits the third signal, τ RA2 is the time when the main fixed node receives the second signal, τ RA1 is the time when the main fixed node receives the first signal, τ RB1 is the time when the first slave fixed node receives the first signal, τ RB2 is the time when the first slave fixed node receives the second signal, τ RB3 is the time when the first slave fixed node receives the third signal, τ RC1 is the time when the second slave fixed node receives the first signal, τ RC2 is the time when the second slave fixed node receives the second signal, τ RC3 is the time when the second slave fixed node receives the third signal, τ RD1 is the time when the third slave fixed node receives the first signal, τ RD2 is the time when the third slave fixed node receives the second signal, τ RD3 is the time when the third slave fixed node receives the third signal; C is the speed of light; S AB is the distance between the main fixed node and the first slave fixed node, S AC is the distance between the main fixed node and the second slave fixed node, S AD is the distance between the main fixed node and the third slave fixed node.

[0079] In the two-way bilateral ranging method in the embodiments of the present invention, the positioning tag only sends one more signal, and the distance difference between the positioning tag and the master and slave fixed nodes can be measured. Then, combined with the two-way bilateral ranging method, the distance from the positioning tag to multiple fixed nodes can be measured through one two-way bilateral ranging, solving the problem of long time consumption of multiple two-way bilateral rangings.

[0080] Step 2: Based on the distances between the positioning tag and several positioning base station nodes, obtain the position range of the positioning tag based on the trilateration algorithm with Kalman filtering.

[0081] It should be noted that the step 2: Based on the distances between the positioning tag and several positioning base station nodes, obtain the position range of the positioning tag based on the trilateration algorithm with Kalman filtering, includes:

[0082] Step 2.1: Based on the distances between the positioning tag and several positioning base station nodes as the system state vector x k , establish a ranging model:

[0083] x k = Ax k-1 + Bu k-1 + ω; (5)

[0084] Wherein, A ∈ R n×n represents the transition matrix between two states, u ∈ Rl represents the controllable input, B ∈ R n×l represents the transition matrix from the control input to the current state, and ω represents the process noise;

[0085] Step 2.2: Ignoring the control input u, obtain:

[0086] x k = Ax k-1 + ω; (6)

[0087] Furthermore, obtain the functional relationship between the current state measurement value and the state value:

[0088] z k = Hx k + v; (7)

[0089] Wherein, k and k - 1 respectively represent the current state and the previous state, x ∈ R n represents the state to be estimated, z ∈ R m represents the actual measurement value, H ∈ R m×n represents the transition matrix of the current state actual measurement value, and v represents the measurement noise;

[0090] Step 2.3: Calculate the Kalman gain:

[0091] K k = Pk|k-1 H T (HP k|k-1 H T +R k ) -1 (8)

[0092] Among them, P k|k-1 represents the predicted covariance matrix, R k represents the observed noise, H ∈ R m×n represents the conversion matrix between the current state and the actual measurement value; when P k|k-1 increases, the Kalman gain K k increases accordingly, and when the noise R k increases, the Kalman gain K k decreases accordingly.

[0093] Step 2.4: Calculate the noise threshold:

[0094] Δν = ν T (HP k|k-1 H T ) -1 v (9)

[0095] First, predict the values of x k and x k-1 . The predicted covariance matrix P k|k-1 formed by the two is calculated to obtain ν = z k - Hx k-1 by Equation (7). The covariance matrix of ν is HP k|k-1 H T . Since H only plays a role in unit conversion, here the test quantity, that is, the noise threshold is Δν = ν T (HP k|k-1 H T ) -1 ν.

[0096] Step 2.5: Judge the noise threshold. If the noise threshold is less than the preset threshold, obtain the position range of the positioning tag. When Δν is less than the preset threshold, it means that the data is reasonable.

[0097] In the embodiments of the present invention, a device with a Kalman filtering algorithm is used to measure the distances from several base station nodes to the positioning tag. The Kalman filtering algorithm has a faster execution speed, smaller data error after processing, and more obvious improvement in accuracy.

[0098] Compared with the prior art, the precise positioning method for subway construction workers provided by the embodiments of the present invention has the following beneficial effects: First, the present invention obtains the distances between the positioning tags of construction workers and several positioning base station nodes based on the bilateral two-way ranging method; then, according to the distances between the positioning tags and several positioning base station nodes, the position range of the positioning tags is obtained based on the trilateration algorithm with Kalman filtering. The present invention uses the two-way bilateral ranging method to calculate the distances between the positioning tags and several positioning base station nodes, and measures the distances from the positioning tags to multiple fixed nodes through one-time two-way bilateral ranging, solving the problem of long time consumption in multiple two-way bilateral rangings. Moreover, the position range of the positioning tags is obtained by using the trilateration algorithm with Kalman filtering, which can effectively improve the positioning accuracy of subway construction workers.

[0099] The embodiments of the present invention provide a precise positioning device for subway construction workers. Figure 2 The structural schematic diagram of a precise positioning device for subway construction workers provided by the embodiments of the present invention is shown. As Figure 2 shown, the device includes:

[0100] A distance measurement module 1, configured to obtain the distances between the positioning tags of subway construction workers and several positioning base station nodes based on the bilateral two-way ranging method;

[0101] A filtering and positioning module 2, configured to obtain the position range of the positioning tags based on the trilateration algorithm with Kalman filtering according to the distances between the positioning tags and several positioning base station nodes.

[0102] Compared with the prior art, the beneficial effects of the precise positioning device for subway construction workers provided by the embodiments of the present invention are the same as those of the precise positioning method for subway construction workers described in the above technical solution, and will not be elaborated here.

[0103] In addition, the embodiments of the present invention further provide an electronic device, including a bus, a transceiver, a memory, a processor, and a computer program stored on the memory and executable on the processor. The transceiver, the memory, and the processor are respectively connected through the bus. When the computer program is executed by the processor, it implements each process of the above-mentioned embodiments of the precise positioning method for subway construction workers and can achieve the same technical effects. To avoid repetition, it will not be elaborated here.

[0104] In addition, the embodiments of the present invention further provide a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by the processor, it implements each process of the above-mentioned embodiments of the precise positioning method for subway construction workers and can achieve the same technical effects. To avoid repetition, it will not be elaborated here.

[0105] A computer-readable storage medium includes: permanent and non-permanent, removable and non-removable media, which are tangible devices that can retain and store instructions for use by an instruction execution device. A computer-readable storage medium includes: electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, and any suitable combination thereof. A computer-readable storage medium includes: phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette tape storage, magnetic tape disk storage or other magnetic storage devices, memory sticks, mechanical encoding devices (such as punched cards or raised structures in grooves on which instructions are recorded), or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined in the embodiments of the present invention, a computer-readable storage medium does not include transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (such as light pulses passing through an optical fiber cable), or electrical signals transmitted through a wire.

[0106] In several embodiments provided in the present application, it should be understood that the disclosed devices, electronic devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Additionally, the displayed or discussed couplings or direct couplings or communication connections between each other can be indirect couplings or communication connections through some interfaces, devices, or units, and can also be in the form of electrical, mechanical, or other connections.

[0107] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units. They can be located in one position or distributed to multiple network units. Some or all of the units can be selected according to actual needs to solve the problems to be solved by the solution of the embodiments of the present invention.

[0108] In addition, in each embodiment of the present invention, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0109] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the embodiments of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (including a personal computer, a server, a data center or other network devices) to execute all or part of the steps of the methods described in the embodiments of the present invention. And the above storage medium includes various media that can store program codes as listed above.

[0110] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technical solution that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A precise positioning method for subway construction workers, characterized in that, it includes: Step 1: Obtain the distances between the positioning tags of construction workers and several positioning base station nodes based on the two-way ranging method; Step 2: Based on the distances between the positioning tags and several positioning base station nodes, obtain the position range of the positioning tags based on the trilateration algorithm with Kalman filtering; The said Step 1: Obtain the distances between the positioning tags of construction workers and several positioning base station nodes based on the two-way ranging method, including: Step 1.1: The positioning tag continuously emits two signals, namely the first signal and the second signal; Step 1.2: Several positioning base station nodes all receive the two signals emitted by the positioning tag; among several positioning base station nodes, there is a main fixed node and several slave fixed nodes; Step 1.3: After receiving the second signal, the main fixed node delays for a period of time and emits a third signal to all slave fixed nodes, and at the same time sends the third signal to the positioning tag; Step 1.4: After receiving the third signal, the positioning tag delays for a period of time and emits a fourth signal to the main fixed node; Step 1.5: According to the time when the positioning tag and the positioning base station node send signals and the time when they receive signals, and combined with the distances between the positioning base station nodes, calculate the distances between the positioning tag and each positioning base station node.

2. A precise positioning method for subway construction workers according to claim 1, characterized in that, there are four positioning base station nodes, one of which is the main fixed node, and the other three are the first slave fixed node, the second slave fixed node and the third slave fixed node respectively; The distance calculation formula between the main fixed node and the positioning tag is: The distance calculation formula between the first slave fixed node and the positioning tag is: In formula (2), The distance calculation formula between the second slave fixed node and the positioning tag is: In formula (3), The distance calculation formula between the third slave fixed node and the positioning tag is: In formula (4) Among them, S A is the distance between the main fixed node and the positioning tag, S B is the distance between the first slave fixed node and the positioning tag, S C is the distance between the second slave fixed node and the positioning tag, S D is the distance between the third slave fixed node and the positioning tag; τ RP′ is the time when the positioning tag receives the third signal, τ SP′ is the time when the positioning tag transmits the second signal, τ SP′4 is the time when the positioning tag transmits the fourth signal, τ RP′4 is the time when the main fixed node receives the fourth signal, τ SA3 is the time when the main fixed node transmits the third signal, τ RA2 is the time when the main fixed node receives the second signal, τ RA1 is the time when the main fixed node receives the first signal, τ RB1 is the time when the first slave fixed node receives the first signal, τ RB2 is the time when the first slave fixed node receives the second signal, τ RB3 is the time when the first slave fixed node receives the third signal, τ RC1 is the time when the second slave fixed node receives the first signal, τ RC2 is the time when the second slave fixed node receives the second signal, τ RC3 is the time when the second slave fixed node receives the third signal, τ RD1 is the time when the third slave fixed node receives the first signal, τ RD2 is the time when the third slave fixed node receives the second signal, τ RD3 is the time when the third slave fixed node receives the third signal; C is the speed of light; S AB is the distance between the main fixed node and the first slave fixed node, S AC is the distance between the main fixed node and the second slave fixed node, S AD is the distance between the main fixed node and the third slave fixed node.

3. A precise positioning method for subway construction workers according to claim 1, characterized in that, The said Step 2: Based on the distances between the positioning tags and several positioning base station nodes, obtain the position range of the positioning tags based on the trilateration algorithm with Kalman filtering, including: Step 2.1: Using the distances between the positioning tag and several positioning base station nodes as the system state vector x k , establish a ranging model: x k = Ax k-1 + Bu k-1 + ω; (5) where \(A\in\mathbb{R}\) n× \(n\) represents the transition matrix between two states, \(u\in\mathbb{R}^l\) represents the controllable input, \(B\in\mathbb{R}\) n×l represents the transition matrix from the control input to the current state, and \(\omega\) represents the process noise; Step 2.2: Ignore the control input u, and get: x k = Ax k-1 + ω; (6) Furthermore, obtain the functional relationship between the current state measurement value and the state value: z k = Hx k + v; (7) where \(k\) and \(k - 1\) represent the current state and the previous state respectively, \(x\in\mathbb{R}\) n represents the state to be estimated, \(z\in\mathbb{R}\) m represents the actual measurement value, \(H\in\mathbb{R}\) m× \(n\) represents the transformation matrix of the actual measurement value of the current state, and \(v\) represents the measurement noise; Step 2.3: Calculate the Kalman gain: K k = P k|k-1 H T (HP k|k-1 H T + R k ) -1 (8) where, P k|k-1 is the predicted covariance matrix, R k is the observed noise, H ∈ R m× n represents the transformation matrix between the current state and the actual measurement value; Step 2.4: Calculate the noise threshold: Δv = v T (HP k|k-1 H T ) -1 v (9) Step 2.5: Judge the noise threshold. If the noise threshold is less than the preset threshold, obtain the position range of the positioning tag.

4. A precise positioning device for subway construction workers, characterized in that, it includes: A distance measurement module for obtaining the distances between the positioning tags of construction workers and several positioning base station nodes based on the two-way ranging method; A filtering and positioning module for obtaining the position range of the positioning tags based on the trilateration algorithm with Kalman filtering according to the distances between the positioning tags and several positioning base station nodes; The said distance measurement module includes: A signal emission module: used for the positioning tag to continuously emit two signals, namely the first signal and the second signal; Signal receiving module: It is used for several positioning base station nodes to receive the two signals emitted by the positioning tag; among the several positioning base station nodes, there is a main fixed node and several slave fixed nodes; Third signal transmitting module: It is used for the main fixed node to transmit a third signal to all slave fixed nodes after a certain delay after receiving the second signal, and at the same time transmit the third signal to the positioning tag; Fourth signal transmitting module: It is used for the positioning tag to transmit a fourth signal to the main fixed node after a certain delay after receiving the third signal; Distance calculation module: It is used to calculate the distances between the positioning tag and each positioning base station node according to the time when the positioning tag and the positioning base station node send signals, the time when they receive signals, and in combination with the distances between the positioning base station nodes themselves.

5. An electronic device, including a bus, a transceiver, a memory, a processor, and a computer program stored on the memory and executable on the processor, the transceiver, the memory, and the processor are connected through the bus, characterized in that when the computer program is executed by the processor, it implements the steps in a precise positioning method for subway construction workers as described in any one of claims 1 to 3.

6. A computer-readable storage medium, on which a computer program is stored, characterized in that when the computer program is executed by the processor, it implements the steps in a precise positioning method for subway construction workers as described in any one of claims 1 to 3.

Images