Shield tunnel limited space safety operation protection early warning system and early warning method

Abstract

The invention provides a shield tunnel limited space safety operation protection early warning system and early warning method, and the system comprises RFID tags and Bluetooth positioning tags which are carried by shield tunnel operation constructors and are in one-to-one correspondence with the constructors; an identity management server; the environment monitoring system is provided with a plurality of sensor assemblies and is used for monitoring temperature, humidity and air quality in the tunnel; a Bluetooth beacon system; the UHF card reader and the face recognition system are arranged at the entrance of the shield tunnel; the environment safety early warning system carries out construction early warning according to the safety threshold range; a fingerprint database based on RSSI; the Bluetooth beacon positioning system is used for carrying out position estimation according to RSSI values of Bluetooth beacons located around the Bluetooth beacon positioning system scanned by the Bluetooth positioning tag and based on fingerprint data of a plurality of reference points in the fingerprint database, and determining the position of each constructor in the tunnel and the dynamic change of the position of each constructor; and the personnel safety early warning system is used for carrying out safety early warning based on the position and the change state of each construction personnel.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel operation safety, and in particular to a shield tunnel limited space safety operation protection early warning system and early warning method. Background Art

[0002] Shield tunnel construction is a construction method widely used in tunnel construction. With the development of shield tunnel technology, the tunnel burial depth (water depth) has reached hundreds of meters in super tunnel projects such as underground tunnels, submarine water guides, and riverbed tunnels. Even the maximum burial depth in hydraulic tunnels (such as water diversion tunnels) has reached more than a kilometer, which puts extremely high demands on the difficulty of construction and the management of the construction process.

[0003] Tunnel construction belongs to the category of confined space construction. The space is limited and relatively isolated from the outside world, and the entrance and exit are restricted. The environment inside the construction site is relatively harsh. Unfavorable underground conditions such as lighting, ventilation, humidity and water coexist, which poses a great hidden danger to the safety of construction workers. Moreover, the harmful gases and dust accumulated during the construction process cannot be diffused in the traditional atmospheric environment, but accumulate in the limited underground construction environment. Although the construction area is equipped with a fresh air system and ventilation conditions, with the advancement of the construction process and the extension of the tunnel space, there are unstable factors in the internal ventilation process and effect, especially toxic gases such as carbon dioxide, methane, and hydrogen sulfide, which have a serious impact on the safety of the construction environment and the health of construction workers. It is easy to cause the accumulation of toxic and harmful, flammable and explosive substances or insufficient oxygen content, resulting in poisoning, combustion and explosion, and hypoxia risks.

[0004] Moreover, in the event of a safety accident caused by an explosion, water leakage, or collapse, on the one hand, the limited space of the shield tunnel construction is closed, partially closed, and has restricted entrances and exits, which affects the time and progress of the search and rescue. On the other hand, after the danger occurs, positioning and search and rescue can only be carried out based on drawings or based on the designed BIM model. In addition, due to the complex environment of the accident site, it is difficult to count the escaped people and the people who need to be searched and rescued. It is difficult to conduct efficient, targeted and rapid search and rescue, and it is difficult to conduct prior monitoring, early warning, and early evacuation. Summary of the invention

[0005] In view of the defects and shortcomings of the prior art, the first aspect of the present invention provides a shield tunnel limited space safety operation protection warning system, comprising:

[0006] RFID tags carried by shield tunnel construction workers, each RFID tag corresponds to a construction worker one by one;

[0007] The Bluetooth positioning tags integrated into the helmets worn by construction workers, each Bluetooth positioning tag corresponds to a construction worker one by one;

[0008] The identity management server is configured to store the identity ID of each construction worker and the facial features, RFID tag information, Bluetooth positioning tag information and construction area information associated with the identity ID;

[0009] The environmental monitoring system arranged in the limited space of the shield tunnel is equipped with multiple sensor components for monitoring the temperature, humidity and air quality in the limited space of the shield tunnel;

[0010] A Bluetooth beacon system deployed in a limited space of a shield tunnel, wherein the Bluetooth beacon system includes a plurality of Bluetooth beacons, each of which has a beacon ID as a unique identifier and a coordinate value in a Cartesian coordinate system established with an entrance of the shield tunnel as an origin;

[0011] A UHF card reader is installed at the entrance of the shield tunnel to read the RFID tags carried by construction workers entering the shield tunnel to preliminarily locate the identity of the construction workers;

[0012] A face recognition system is set up at the entrance of the shield tunnel to collect face images, perform face recognition and registration on construction workers who enter the limited space of the shield tunnel through the entrance, and count the total number of construction workers who enter the limited space of the shield tunnel;

[0013] Environmental safety early warning system, which is used to issue construction early warnings based on real-time monitoring of temperature, humidity and air quality and safety threshold ranges;

[0014] A fingerprint library based on RSSI, used to store fingerprint data of multiple selected reference points in the limited space of the shield tunnel, each fingerprint data includes a coordinate value of the reference point in the Cartesian coordinate system and its corresponding RSSI value;

[0015] A Bluetooth beacon positioning system is connected to the Bluetooth beacon system and the RSSI-based fingerprint library; the Bluetooth beacon positioning system is configured to estimate the position of each construction worker in the limited space of the shield tunnel and its dynamic changes based on the RSSI values ​​of the Bluetooth beacons located around it scanned by the Bluetooth positioning tag and the fingerprint data of multiple reference points in the fingerprint library;

[0016] The personnel safety warning system is connected to the Bluetooth beacon positioning system and is configured to issue warnings based on the position of each construction worker in the limited space of the shield tunnel and its changing state.

[0017] As an optional implementation, the RFID tag and Bluetooth positioning tag assigned to each construction worker are integrated into the safety helmet worn by the construction worker, and establish a one-to-one corresponding relationship with the construction worker's identity ID.

[0018] As an optional implementation, the UHF card reader is configured to determine the identity of the construction workers within the antenna radiation field of the UHF card reader by reading the RFID tags carried by the construction workers entering the shield tunnel for operation, and store the corresponding construction worker identity information in a cache library according to the identity of the construction workers corresponding to the read RFID tags.

[0019] As an optional implementation, the facial recognition system includes a camera for acquiring facial images and an edge computing system for performing identity recognition based on the facial images of construction workers captured by the camera. The edge computing system performs 1:1 facial recognition based on the captured facial images of construction workers and the identity information of construction workers stored in the cache, determines the identities of construction workers entering the construction area, registers and counts them, and summarizes the total number of construction workers entering the limited space of the shield tunnel.

[0020] As an optional implementation, the RSSI-based fingerprint library is configured to be constructed by selecting reference points offline and collecting and recording RSSI data of the reference points, wherein:

[0021] Starting from the entrance of the shield tunnel and extending to the construction area within the limited space of the shield tunnel, reference points are set in a way that the adjacent reference points are spaced at preset intervals, and reference points are configured for ventilation openings, boundary locations of different geological conditions, construction equipment locations, tunnel boundaries, and high-voltage power areas;

[0022] For each reference point, a reference Bluetooth positioning tag is used to stand still and measure the RSSI values ​​of the Bluetooth beacons around it. The reference Bluetooth positioning tag performs multiple RSSI measurements on each visible Bluetooth beacon within its scanning range, and calculates the average value as the RSSI value of the reference point for a certain Bluetooth beacon;

[0023] For each reference point, record its coordinate value in the Cartesian coordinate system;

[0024] The coordinate value of each reference point and the RSSI value of the Bluetooth beacon corresponding to each reference point are stored one by one to construct an initial fingerprint library.

[0025] As an optional implementation, the final fingerprint library is obtained by performing outlier detection and elimination and Gaussian smoothing on the initial fingerprint library, which is used to estimate the position of construction workers in the limited space of the shield tunnel and their dynamic changes.

[0026] As an optional implementation, the Bluetooth beacon positioning system is configured to estimate the position of each construction worker in the limited space of the shield tunnel based on the RSSI value of the Bluetooth beacon located around the Bluetooth positioning tag and the fingerprint data of multiple reference points in the fingerprint library, including:

[0027] When construction workers carry Bluetooth positioning tags and move in the limited space of a shield tunnel, the Bluetooth positioning tags measure the RSSI values ​​of the surrounding Bluetooth beacons in real time and report them to the Bluetooth beacon positioning system according to a predetermined period;

[0028] The Bluetooth beacon positioning system determines the RSSI value of each Bluetooth beacon measured by the construction worker's Bluetooth positioning tag by taking the average value of multiple measurements;

[0029] The Bluetooth beacon positioning system matches the RSSI value of each Bluetooth beacon corresponding to each construction worker after mean processing with the fingerprint data in the fingerprint library, estimates the real-time location of each construction worker, and dynamically determines the movement status and safety warning of the construction worker based on the time series changes of the real-time location.

[0030] As an optional implementation, the Bluetooth beacon positioning system estimates the real-time location of each construction worker by matching the RSSI value of each Bluetooth beacon after mean processing corresponding to each construction worker with the fingerprint data in the fingerprint library, including:

[0031] The RSSI value of each Bluetooth beacon corresponding to each construction worker after mean processing is used as the real-time RSSI vector, and the similarity between the real-time RSSI vector and the RSSI vector of each reference point in the fingerprint library is calculated;

[0032] According to the calculated similarity, determine the K reference points that are most similar to the real-time RSSI vector;

[0033] Calculate the weight of each reference point among the most similar K reference points;

[0034] According to the weight of each reference point, the position estimate of the construction worker is determined based on the weighted average method as his real-time position coordinates in the limited space of the shield tunnel.

[0035] As an optional implementation, the dynamic judgment of the movement state of the construction personnel and the safety warning based on the time series change of the real-time position includes:

[0036] The motion state of the construction personnel is determined by analyzing the estimated position value of the construction personnel and its dynamic changes. If the position coordinates of the construction personnel remain unchanged or the change value is within the preset amplitude range during multiple consecutive positioning cycles, the construction personnel is determined to be in a stationary state; conversely, if the position coordinates change beyond the preset amplitude range, the construction personnel is determined to be in a moving state;

[0037] According to the different areas pre-divided in the limited space of the shield tunnel, the boundary coordinates of each area are pre-set; when the location coordinates of the construction personnel show that they enter or leave the preset specific area, the corresponding alarm is immediately issued, and the location and related information of the construction personnel are highlighted on the screen of the monitoring center;

[0038] The construction workers' stay time in each area is recorded. When the construction workers stay in a specific area for longer than the system safety threshold, an early warning message is issued to remind the management staff or the construction workers closest to them to pay attention to whether the personnel encounter difficulties or abnormal situations, and the location and related information of the construction workers are highlighted on the screen of the monitoring center.

[0039] As an optional implementation manner, the similarity between the real-time RSSI vector and the RSSI vector of each reference point in the fingerprint library uses Euclidean distance, Manhattan distance or cosine similarity as a similarity metric.

[0040] According to a second aspect of the present invention, a shield tunnel limited space safety operation protection early warning method is also proposed, comprising the following steps:

[0041] (1) Complete Bluetooth beacon deployment, reference point selection, and fingerprint database establishment in the offline phase, including the following operations:

[0042] Step 1.1, multiple Bluetooth beacons are arranged according to the construction area and construction length, each Bluetooth beacon has a beacon ID as a unique identifier, and a coordinate value in a Cartesian coordinate system established with the shield tunnel entrance as the origin; the Bluetooth beacons are installed at a distance of 10 to 20 meters in a manner extending inward from the shield tunnel entrance, and the installation height of the Bluetooth beacons is 1.5 to 2.5 meters; when installing each Bluetooth beacon, the position coordinates thereof are accurately measured and recorded by a measuring instrument, that is, the coordinate values ​​in a Cartesian coordinate system established with the shield tunnel entrance as the origin;

[0043] Step 1.2: Test and configure the transmit power and broadcast frequency of the Bluetooth beacon;

[0044] Step 1.3, starting from the entrance of the shield tunnel and extending to the construction area within the limited space of the shield tunnel, set reference points in a way that the adjacent reference points are spaced at preset intervals, and configure reference points for ventilation openings, boundary positions of different geological conditions, construction equipment positions, tunnel boundaries, and high-voltage power areas;

[0045] Step 1.4: For each reference point, use a reference Bluetooth positioning tag to stand still and measure the RSSI values ​​of the Bluetooth beacons around it. The reference Bluetooth positioning tag performs multiple RSSI measurements on each visible Bluetooth beacon within its scanning range, and calculates the average value as the RSSI value of the reference point for a Bluetooth beacon.

[0046] Step 1.5: For each reference point, record its coordinate value in the Cartesian coordinate system, and store the coordinate value of each reference point and the RSSI value of the Bluetooth beacon corresponding to each reference point in a one-to-one correspondence to construct an initial fingerprint library.

[0047] Step 1.6, performing outlier detection and elimination and Gaussian smoothing processing on the initial fingerprint library to obtain a final fingerprint library for estimating the position of construction personnel in the limited space of the shield tunnel and its dynamic changes;

[0048] (2) Online real-time monitoring of the movement status of construction workers and safety warnings, including the following operations:

[0049] Step 2.1, when the construction workers move in the limited space of the shield tunnel, the Bluetooth positioning tag they carry packages the measured Bluetooth beacon RSSI value and beacon identification information, and sends it to the Bluetooth beacon positioning system according to the reporting frequency. Each data packet contains the tag ID of the Bluetooth positioning tag, the measurement time, the beacon ID and the corresponding RSSI value;

[0050] Step 2.2, the Bluetooth beacon positioning system receives the data packet reported by the Bluetooth positioning tag corresponding to each construction worker, and determines the RSSI value of each Bluetooth beacon measured by the Bluetooth positioning tag of the construction worker by taking the average value of multiple measurements;

[0051] Step 2.3, the Bluetooth beacon positioning system uses the RSSI value of each Bluetooth beacon corresponding to each construction worker after mean processing as the real-time RSSI vector, calculates the similarity between the real-time RSSI vector and the RSSI vector of each reference point in the fingerprint library, and uses Euclidean distance, Manhattan distance or cosine similarity as the similarity metric;

[0052] Step 2.4, according to the calculated similarity, determine the K reference points that are most similar to the real-time RSSI vector and calculate the weight of each reference point in the K most similar reference points;

[0053] Step 2.5, according to the weight of each reference point, determine the estimated position value of the construction personnel based on the weighted average method as the real-time position coordinate of the construction personnel in the limited space of the shield tunnel;

[0054] Step 2.6: Dynamically determine the movement status of the construction personnel and issue safety warnings based on the time series changes of the construction personnel's real-time positions.

[0055] As an optional embodiment, the method of dynamically judging the motion state of the construction personnel and providing a safety warning according to the time series change of the real-time position of the construction personnel includes:

[0056] The motion state of the construction personnel is determined by analyzing the estimated position value of the construction personnel and its dynamic changes. If the position coordinates of the construction personnel remain unchanged or the change value is within the preset amplitude range during multiple consecutive positioning cycles, the construction personnel is determined to be in a stationary state; conversely, if the position coordinates change beyond the preset amplitude range, the construction personnel is determined to be in a moving state;

[0057] According to the different areas pre-divided in the limited space of the shield tunnel, the boundary coordinates of each area are pre-set; when the location coordinates of the construction personnel show that they enter or leave the preset specific area, the corresponding alarm is immediately issued, and the location and related information of the construction personnel are highlighted on the screen of the monitoring center;

[0058] The construction workers' stay time in each area is recorded. When the construction workers stay in a specific area for longer than the system safety threshold, an early warning message is issued to remind the management staff or the construction workers closest to them to pay attention to whether the personnel encounter difficulties or abnormal situations, and the location and related information of the construction workers are highlighted on the screen of the monitoring center.

[0059] The shield tunnel limited space safety operation protection warning system and warning method according to the above embodiments have the following significant advantages:

[0060] (1) The shield tunnel limited space safety operation protection warning system of the present invention is provided with a UHF card reader at the entrance of the shield tunnel. After reading the RFID tag carried by the construction personnel and preliminarily locating the identity of the construction personnel, the scope of the personnel entering can be preliminarily delineated, which is conducive to the subsequent face recognition registration using a 1:1 face recognition method instead of a 1:N recognition method, thereby improving the efficiency and accuracy of face recognition; combining the RFID tag reading system with the face recognition system to collect face images and identify and register the construction personnel entering the construction area, the identity of the entrant can be more accurately verified through a dual identity authentication method, effectively ensuring the safety of the construction area, and facilitating the subsequent efficient rescue of personnel at a fixed point and person when personnel are evacuated or in danger;

[0061] (2) Since it is difficult to accurately obtain the location of construction workers and issue safety warnings in the complex environment of shield tunnels, in order to avoid and discover safety problems in advance, the safety protection warning system of the present invention integrates Bluetooth positioning tags in the safety helmets of construction workers, and combines the Bluetooth beacon system deployed in the shield tunnel, and uses the RSSI-based fingerprint library for position estimation. Compared with the existing methods, it can more accurately determine the position of each construction worker in the limited space of the shield tunnel and its dynamic changes, and perceive the handling of various accidents and special situations in advance, which is helpful to discover problems before dangerous situations occur and quickly issue local warnings, and quickly locate personnel and notify the nearest construction personnel to confirm safety and intervene, so as to reduce the occurrence of dangers and improve rescue efficiency.

[0062] (3) Unlike existing systems that can only monitor environmental parameters but lack an effective early warning mechanism, the safety protection early warning system of the present invention is designed as an environmental safety early warning system. By receiving real-time monitored temperature, humidity and air quality data, such as carbon dioxide content, hydrogen sulfide / methane and other harmful gas content, oxygen content, etc., and issuing construction early warnings based on the safety threshold range, construction personnel can take timely measures to respond to environmental changes, such as ventilation, adjusting construction progress, or safely evacuating the construction area in advance, thereby ensuring construction safety;

[0063] (4) The personnel safety warning system designed by the present invention is connected to the Bluetooth beacon positioning system, and can issue warnings based on the position and changing status of each construction worker in the limited space of the shield tunnel. For example, when a construction worker approaches a dangerous area or stays in a dangerous area for too long, an alarm can be issued in time, thereby achieving a more targeted and dynamic personnel safety warning.

[0064] It should be understood that all combinations of the aforementioned concepts and the additional concepts described in more detail below can be considered as part of the inventive subject matter of the present disclosure as long as such concepts are not mutually inconsistent. In addition, all combinations of the claimed subject matter are considered as part of the inventive subject matter of the present disclosure.

[0065] The foregoing and other aspects, embodiments and features of the present invention can be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as the features and / or beneficial effects of the exemplary embodiments, will be apparent from the following description or learned from the practice of the specific embodiments according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The accompanying drawings are not intended to be drawn to scale. In the accompanying drawings, each identical or nearly identical component shown in each figure may be represented by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings.

[0067] Figure 1 It is a schematic diagram of a shield tunnel limited space safety operation protection warning system according to an embodiment of the present invention.

[0068] Figure 2 is a schematic diagram of an environment monitoring system according to an embodiment of the present invention.

[0069] Figure 3 is a schematic diagram of a UHF reading system according to an embodiment of the present invention.

[0070] Figure 4 is a schematic diagram of a Bluetooth beacon system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0071] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.

[0072] Various aspects of the present invention are described in this disclosure with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present invention. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed by the present invention are not limited to any implementation. In addition, some aspects disclosed by the present invention can be used alone or in any appropriate combination with other aspects disclosed by the present invention.

[0073] {Example 1}

[0074] Combination Figure 1 to Figure 4 According to the example shown, a shield tunnel limited space safety operation protection warning system according to an embodiment of the present invention includes:

[0075] RFID tags 101 carried by shield tunnel construction workers, each RFID tag corresponding to a construction worker;

[0076] The Bluetooth positioning tags 102 are integrated in the safety helmets worn by the construction workers, and each Bluetooth positioning tag 102 corresponds to a construction worker one by one;

[0077] The identity management server 110 is configured to store the identity ID of each construction worker and the facial features, RFID tag information, Bluetooth positioning tag information and construction area information associated with the identity ID;

[0078] The environmental monitoring system 120 arranged in the limited space of the shield tunnel is equipped with a plurality of sensor components for monitoring the temperature, humidity and air quality in the limited space of the shield tunnel;

[0079] A Bluetooth beacon system 130 is deployed in a limited space of a shield tunnel, wherein the Bluetooth beacon system 130 includes a plurality of Bluetooth beacons 131, each of which has a beacon ID as a unique identifier and a coordinate value in a Cartesian coordinate system established with an entrance of the shield tunnel as an origin;

[0080] A UHF card reader 140 is provided at the entrance of the shield tunnel to read the RFID tag 101 carried by the construction personnel entering the shield tunnel for operation, and to preliminarily locate the identity of the construction personnel;

[0081] A face recognition system 150 is set up at the entrance of the shield tunnel to collect face images of construction personnel who enter the limited space of the shield tunnel through the entrance, perform face recognition and registration, and count the total number of construction personnel who enter the limited space of the shield tunnel;

[0082] The environmental safety early warning system 160 is connected to the monitoring center 1000 and is used to issue construction early warnings based on the real-time monitored temperature, humidity and air quality and the safety threshold range;

[0083] The RSSI-based fingerprint library 200 is used to store fingerprint data of multiple selected reference points in the limited space of the shield tunnel, each fingerprint data includes the coordinate value of the reference point in the Cartesian coordinate system and the RSSI value corresponding thereto;

[0084] A Bluetooth beacon positioning system 170 is connected to the Bluetooth beacon system and the RSSI-based fingerprint library; the Bluetooth beacon positioning system is configured to estimate the position of each construction worker in the limited space of the shield tunnel and its dynamic changes based on the RSSI values ​​of the Bluetooth beacons located around it scanned by the Bluetooth positioning tag and the fingerprint data of multiple reference points in the fingerprint library; and

[0085] The personnel safety warning system 180 is connected to the Bluetooth beacon positioning system and is configured to issue warnings based on the position of each construction worker in the limited space of the shield tunnel and its changing state.

[0086] As an optional implementation, the RFID tag and Bluetooth positioning tag assigned to each construction worker are integrated into the safety helmet worn by the construction worker, and establish a one-to-one corresponding relationship with the construction worker's identity ID.

[0087] As an optional implementation, the UHF card reader is configured to determine the identity of the construction workers within the antenna radiation field of the UHF card reader by reading the RFID tags carried by the construction workers entering the shield tunnel for operation, and store the corresponding construction worker identity information in a cache library based on the identity of the construction workers corresponding to the read RFID tags.

[0088] As an optional implementation, the facial recognition system includes a camera for acquiring facial images and an edge computing system (for example, a lightweight edge computing device deployed at the entrance site) for identity recognition based on the facial images of construction workers captured by the camera. The edge computing system performs 1:1 facial recognition based on the captured facial images of the construction workers and the identity information of the construction workers stored in the cache, determines the identities of the construction workers entering the construction area, registers and counts them, and summarizes the total number of construction workers entering the limited space of the shield tunnel.

[0089] It should be understood that the edge computing system usually has the architectural design of a computer system, with a processor, memory and data bus system, and can pre-store commercial face recognition software algorithms or trained face recognition models in the memory, including but not limited to recognition models based on neural network models such as CNN, which are called and executed by the processor. Based on the real-time collected face data, it compares and matches the facial feature information of the construction workers in the cache library to perform face recognition, identify the identity of the construction workers and register them.

[0090] As an optional implementation, the RSSI-based fingerprint library 200 is configured to be constructed by selecting reference points offline and collecting and recording RSSI data of the reference points, wherein:

[0091] Starting from the entrance of the shield tunnel and extending to the construction area within the limited space of the shield tunnel, reference points are set in a way that the adjacent reference points are spaced at a preset interval (the setting range is 5 to 10 meters), and reference points are configured for ventilation openings, boundary positions of different geological conditions, construction equipment positions, tunnel boundaries, and high-voltage power areas;

[0092] For each reference point, a reference Bluetooth positioning tag is used to stand still and measure the RSSI values ​​of the Bluetooth beacons around it. The reference Bluetooth positioning tag performs multiple RSSI measurements on each visible Bluetooth beacon within its scanning range, and calculates the average value as the RSSI value of the reference point for a certain Bluetooth beacon;

[0093] For each reference point, record its coordinate value in the Cartesian coordinate system;

[0094] The coordinate value of each reference point and the RSSI value of the Bluetooth beacon corresponding to each reference point are stored one by one to construct an initial fingerprint library.

[0095] As an optional implementation, the final fingerprint library is obtained by performing outlier detection and elimination and Gaussian smoothing on the initial fingerprint library, which is used to estimate the position of construction workers in the limited space of the shield tunnel and their dynamic changes.

[0096] As an optional method, outlier detection and elimination can be determined based on the 3σ criterion. For example, if the deviation of a certain RSSI measurement value from the RSSI average value of the reference point to the same beacon exceeds 3 standard deviations, the measurement value is considered to be an outlier and is eliminated. Thus, the collected raw fingerprint data is optimized to improve the quality of the fingerprint library and positioning accuracy.

[0097] Then, Gaussian smoothing is performed on the RSSI data after the abnormal data is removed, for example, a Gaussian filtering method is used to reduce noise interference of the data.

[0098] Finally, the processed RSSI value and position coordinates of each reference point are stored according to a certain data structure to construct a fingerprint library. As an optional example, a database management system (such as MySQL, Oracle, etc.) can be used to store the fingerprint library, where the table structure can be designed to include fields: reference point ID, position coordinates (x, y, z), beacon ID1, RSSI1, beacon ID2, RSSI2, ... In a specific embodiment, the field can be determined according to the actual number of beacons.

[0099] As an optional implementation, the Bluetooth beacon positioning system is configured to estimate the position of each construction worker in the limited space of the shield tunnel based on the RSSI value of the Bluetooth beacon located around the Bluetooth positioning tag and the fingerprint data of multiple reference points in the fingerprint library, including:

[0100] When construction workers carry Bluetooth positioning tags and move in the limited space of a shield tunnel, the Bluetooth positioning tags 102 measure the RSSI values ​​of the surrounding Bluetooth beacons 131 in real time and report them to the Bluetooth beacon positioning system 170 according to a predetermined period;

[0101] The Bluetooth beacon positioning system determines the RSSI value of each Bluetooth beacon measured by the construction worker's Bluetooth positioning tag by taking the average value of multiple measurements;

[0102] The Bluetooth beacon positioning system matches the RSSI value of each Bluetooth beacon corresponding to each construction worker after mean processing with the fingerprint data in the fingerprint library, estimates the real-time location of each construction worker, and dynamically determines the movement status and safety warning of the construction worker based on the time series changes of the real-time location.

[0103] As an optional implementation, the Bluetooth beacon positioning system estimates the real-time location of each construction worker by matching the RSSI value of each Bluetooth beacon after mean processing corresponding to each construction worker with the fingerprint data in the fingerprint library, including:

[0104] The RSSI value of each Bluetooth beacon corresponding to each construction worker after mean processing is used as the real-time RSSI vector, and the similarity between the real-time RSSI vector and the RSSI vector of each reference point in the fingerprint library is calculated;

[0105] According to the calculated similarity, determine the K reference points that are most similar to the real-time RSSI vector;

[0106] Calculate the weight of each reference point among the most similar K reference points;

[0107] According to the weight of each reference point, the position estimate of the construction worker is determined based on the weighted average method as his real-time position coordinates in the limited space of the shield tunnel.

[0108] As an optional implementation, dynamically judging the movement status of construction workers and providing safety warnings based on the temporal changes of real-time positions includes:

[0109] The motion state of the construction personnel is determined by analyzing the estimated position value of the construction personnel and its dynamic changes. If the position coordinates of the construction personnel remain unchanged or the change value is within the preset amplitude range during multiple consecutive positioning cycles, the construction personnel is determined to be in a stationary state; conversely, if the position coordinates change beyond the preset amplitude range, the construction personnel is determined to be in a moving state;

[0110] According to the different areas pre-divided in the limited space of the shield tunnel, the boundary coordinates of each area are pre-set; when the position coordinates of the construction personnel show that they enter or leave the preset specific area, a corresponding alarm is immediately issued, and the position and relevant information of the construction personnel are highlighted on the screen of the monitoring center 1000;

[0111] The construction workers' stay time in each area is recorded. When the construction workers' stay time in a specific area exceeds the system safety threshold time, an early warning message is issued to remind the management personnel or the construction workers closest to them to pay attention to whether the personnel encounter difficulties or abnormal situations, and the location and related information of the construction workers are highlighted on the screen of the monitoring center 1000.

[0112] As an optional implementation, the similarity between the real-time RSSI vector and the RSSI vector of each reference point in the fingerprint library uses Euclidean distance, Manhattan distance or cosine similarity as a similarity metric.

[0113] {Example 2}

[0114] Combination Figure 1 to Figure 4 The shield tunnel limited space safety operation protection warning system of the above embodiment, according to this embodiment, eliminates a shield tunnel limited space safety operation protection warning method, including the following steps:

[0115] (1) Complete Bluetooth beacon deployment, reference point selection, and fingerprint database establishment in the offline phase, including the following operations:

[0116] Step 1.1, multiple Bluetooth beacons are arranged according to the construction area and construction length, each Bluetooth beacon has a beacon ID as a unique identifier, and a coordinate value in a Cartesian coordinate system established with the shield tunnel entrance as the origin; the Bluetooth beacons are installed at a distance of 10 to 20 meters in a manner extending inward from the shield tunnel entrance, and the installation height of the Bluetooth beacons is 1.5 to 2.5 meters; when installing each Bluetooth beacon, the position coordinates thereof are accurately measured and recorded by a measuring instrument, that is, the coordinate values ​​in a Cartesian coordinate system established with the shield tunnel entrance as the origin;

[0117] Step 1.2: Test and configure the transmit power and broadcast frequency of the Bluetooth beacon;

[0118] Step 1.3, starting from the entrance of the shield tunnel and extending to the construction area within the limited space of the shield tunnel, set reference points in a way that the adjacent reference points are spaced at preset intervals, and configure reference points for ventilation openings, boundary positions of different geological conditions, construction equipment positions, tunnel boundaries, and high-voltage power areas;

[0119] Step 1.4: For each reference point, use a reference Bluetooth positioning tag to stand still and measure the RSSI values ​​of the Bluetooth beacons around it. The reference Bluetooth positioning tag performs multiple RSSI measurements on each visible Bluetooth beacon within its scanning range, and calculates the average value as the RSSI value of the reference point for a Bluetooth beacon.

[0120] Step 1.5: For each reference point, record its coordinate value in the Cartesian coordinate system, and store the coordinate value of each reference point and the RSSI value of the Bluetooth beacon corresponding to each reference point in a one-to-one correspondence to construct an initial fingerprint library.

[0121] Step 1.6, perform outlier detection and elimination, and Gaussian smoothing on the initial fingerprint library to obtain the final fingerprint library, which is used to estimate the position of construction workers in the limited space of the shield tunnel and their dynamic changes;

[0122] (2) Online real-time monitoring of the movement status of construction workers and safety warnings, including the following operations:

[0123] Step 2.1, when the construction workers move in the limited space of the shield tunnel, the Bluetooth positioning tag they carry packages the measured Bluetooth beacon RSSI value and beacon identification information, and sends it to the Bluetooth beacon positioning system according to the reporting frequency. Each data packet contains the tag ID of the Bluetooth positioning tag, the measurement time, the beacon ID and the corresponding RSSI value;

[0124] Step 2.2, the Bluetooth beacon positioning system receives the data packet reported by the Bluetooth positioning tag corresponding to each construction worker, and determines the RSSI value of each Bluetooth beacon measured by the Bluetooth positioning tag of the construction worker by taking the average value of multiple measurements;

[0125] Step 2.3, the Bluetooth beacon positioning system uses the RSSI value of each Bluetooth beacon corresponding to each construction worker after mean processing as the real-time RSSI vector, calculates the similarity between the real-time RSSI vector and the RSSI vector of each reference point in the fingerprint library, and uses Euclidean distance, Manhattan distance or cosine similarity as the similarity metric;

[0126] Step 2.4, according to the calculated similarity, determine the K reference points that are most similar to the real-time RSSI vector and calculate the weight of each reference point in the K most similar reference points;

[0127] Step 2.5, according to the weight of each reference point, determine the estimated position value of the construction personnel based on the weighted average method as the real-time position coordinate of the construction personnel in the limited space of the shield tunnel;

[0128] Step 2.6: Dynamically determine the movement status of the construction personnel and issue safety warnings based on the time series changes of the construction personnel's real-time positions.

[0129] As an optional embodiment, dynamically judging the movement state of the construction workers and providing safety warnings according to the time series changes of the real-time positions of the construction workers includes:

[0130] The motion state of the construction personnel is determined by analyzing the estimated position value of the construction personnel and its dynamic changes. If the position coordinates of the construction personnel remain unchanged or the change value is within the preset amplitude range during multiple consecutive positioning cycles, the construction personnel is determined to be in a stationary state; conversely, if the position coordinates change beyond the preset amplitude range, the construction personnel is determined to be in a moving state;

[0131] According to the different areas pre-divided in the limited space of the shield tunnel, the boundary coordinates of each area are pre-set; when the location coordinates of the construction personnel show that they enter or leave the preset specific area, the corresponding alarm is immediately issued, and the location and related information of the construction personnel are highlighted on the screen of the monitoring center;

[0132] The construction workers' stay time in each area is recorded. When the construction workers stay in a specific area for longer than the system safety threshold, an early warning message is issued to remind the management staff or the construction workers closest to them to pay attention to whether the personnel encounter difficulties or abnormal situations, and the location and related information of the construction workers are highlighted on the screen of the monitoring center.

[0133] {Example 3}

[0134] In combination with the shield tunnel limited space safety operation protection warning system and warning method of the above embodiments, we will describe the implementation of various aspects in more detail in this example.

[0135] 1.1 Sensor deployment for environmental monitoring

[0136] Combination Figure 1 and Figure 2 As shown, according to the requirements of the monitored air quality, high-precision and high-sensitivity sensors are selected, including carbon monoxide sensors, carbon dioxide sensors, hydrogen sulfide sensors, methane sensors, oxygen sensors, and temperature and humidity sensors, which are used to monitor the carbon monoxide concentration, carbon dioxide concentration, hydrogen sulfide concentration, methane concentration, oxygen content level, and temperature and humidity data in the limited space of the shield tunnel respectively.

[0137] As an optional implementation, monitoring points are set up at certain distances and in the construction area within the limited space of the shield tunnel, and multiple sensors are configured to conduct real-time and dynamic air quality monitoring. The monitoring data is reported to the monitoring center 1000 according to the reporting period and stored in its server. The environmental safety warning system 160 issues construction warnings based on the real-time monitored temperature, humidity and air quality and within the safety threshold range.

[0138] The environmental safety early warning system 160 is connected to the monitoring center 1000 and is used to display real-time monitoring data on the screen of the monitoring center and display construction early warning information.

[0139] As an optional embodiment, a display screen is provided at the tunnel entrance and connected to a monitoring center to display real-time monitored environmental data, including temperature, humidity and air quality, on the display screen at the tunnel entrance, to facilitate construction workers and management personnel to observe and respond when entering.

[0140] For example, in the limited space of a shield tunnel, poor ventilation and other conditions may lead to insufficient oxygen content. Under normal circumstances, the oxygen content in the air is about 21%. When the oxygen content is lower than 19.5%, the operator will experience symptoms such as rapid breathing and decreased judgment; when the oxygen content is lower than 6%, it will cause death in a short period of time. Through the environmental safety early warning system 160 of the embodiment of the present invention, the air quality and oxygen content are monitored in real time. Once the oxygen concentration drops to a dangerous threshold, an alarm can be issued in time to remind the operator to evacuate or take appropriate ventilation measures to ensure the safety of the personnel.

[0141] At the same time, before construction workers enter, the air quality in the limited space of the shield tunnel is continuously monitored. If the safety threshold is not met, a display and alarm will be given at the entrance, indicating that the current time is not suitable for entering the construction. Management personnel are required to take appropriate ventilation measures to improve the air environment until the air quality standards are met before entering the construction area.

[0142] In the embodiment of the present invention, the communication between the sensor and the monitoring center preferably adopts a combination of Bluetooth and Wi-Fi. The sensor is equipped with a Bluetooth module, which first transmits data to a nearby Bluetooth gateway (installed at an appropriate location in the tunnel) based on the Bluetooth communication protocol, and then the Bluetooth gateway forwards the data to the server of the monitoring center via Wi-Fi, which can not only use the low power consumption characteristics of Bluetooth for close-range data collection, but also use the high-speed transmission capability of Wi-Fi to reliably transmit data to the monitoring center for processing and analysis.

[0143] 2. Bluetooth beacon deployment and configuration

[0144] (1) Bluetooth beacon installation location planning

[0145] The interval of Bluetooth beacons can be determined according to the length, shape and expected positioning accuracy requirements of the shield tunnel. Generally, it is more appropriate to install a Bluetooth beacon every 10-20 meters in a straight section of the tunnel. For example, if the tunnel length is 1,000 meters, about 50-100 beacons can be installed in the straight section. For special areas such as bends and branches, the interval needs to be appropriately reduced to ensure that the signal can be continuously covered and accurately positioned. For example, in a bend with a small radius, the beacon interval can be shortened to 5-10 meters.

[0146] Taking into account the activity range of construction workers in the tunnel and the characteristics of signal propagation, Bluetooth beacons are usually installed in the middle or slightly higher part of the tunnel wall. The installation height is usually chosen between 1.5-2.5 meters to avoid the Bluetooth beacon being blocked by construction equipment or materials, while also ensuring that the signal has good coverage in both horizontal and vertical directions.

[0147] When installing each Bluetooth beacon, a high-precision measuring instrument (such as a total station or a laser rangefinder) can be used to accurately record its position coordinates. For the three-dimensional spatial coordinates in the tunnel, it is preferred to use the tunnel entrance as the origin (such as the midpoint of the intersection of the section where the entrance is located and the bottom surface), establish a Cartesian coordinate system, and record the three-dimensional spatial coordinates of each beacon separately.

[0148] (2) Bluetooth beacon parameter configuration

[0149] The transmission power of Bluetooth beacons determines the coverage and strength of the signal. In a shield tunnel environment, the transmission power needs to be adjusted according to the structure of the tunnel, the distribution of obstacles, and the requirements for positioning accuracy. Generally, the transmission power of Bluetooth beacons can be adjusted between -20dBm and +20dBm.

[0150] In the early stage of tunnel construction, the transmission power can be set to a medium level, such as 0dBm, and then the signal strength test can be performed at different locations in the tunnel. Use a Bluetooth signal strength detection device (such as a Bluetooth signal analyzer or a smartphone application with Bluetooth detection function) to measure the signal strength at different distances from the beacon (such as 1 meter, 5 meters, 10 meters, etc.) and in different directions. According to the test results, if the signal strength in some areas is too weak to meet the positioning requirements, the transmission power can be appropriately increased; if the signal strength is too strong, it will cause increased signal interference and excessive power consumption, and the transmission power should be reduced at this time.

[0151] The broadcast frequency of Bluetooth beacons affects the efficiency of the positioning tag in receiving and processing signals. Common Bluetooth beacon broadcast frequencies include 1Hz, 10Hz, etc. In a shield tunnel environment, in order to reduce power consumption and signal interference while ensuring real-time positioning, the broadcast frequency is usually set to around 5Hz.

[0152] (III) Communication configuration of Bluetooth positioning tags and Bluetooth beacons

[0153] (1) The Bluetooth positioning tag carried by the construction workers has a Bluetooth scanning function. The tag actively scans the surrounding Bluetooth beacons at a certain period (for example, 0.5s). When the Bluetooth positioning tag enters the signal coverage range of the Bluetooth beacon, it can detect the broadcast signal of the beacon.

[0154] During the scanning process, the Bluetooth positioning tag will obtain the identification information of the Bluetooth beacon (such as the beacon ID), which is a unique identifier to distinguish different beacons. At the same time, the Bluetooth positioning tag measures the received beacon signal strength value, that is, the RSSI value.

[0155] The Bluetooth positioning tag measures the signal strength of each detected Bluetooth beacon around it multiple times and then takes the average value as the final RSSI measurement value of the beacon to reduce the impact of measurement errors and signal fluctuations.

[0156] (2) The Bluetooth positioning tag carried by the construction personnel packages the measured RSSI value of the Bluetooth beacon and the beacon identification information (such as the beacon ID) to form a data packet, and reports it to the Bluetooth beacon positioning system 170 according to the set reporting cycle. Each data packet contains information such as the tag ID, measurement time, beacon ID, and corresponding RSSI value. For example, the format of a data packet can be designed as: [tag ID (16 bits), measurement time (32 bits, accurate to milliseconds), beacon ID (8 bits), RSSI value (8 bits, in dBm)].

[0157] In the limited space of a shield tunnel, data packets can be transmitted in a variety of ways, such as Bluetooth, Wi-Fi, or low-power wide area network (LPWAN) technology.

[0158] Taking into account the scale of the tunnel, network infrastructure, and data transmission requirements, it is particularly preferred to use a combination of Bluetooth and Wi-Fi. The Bluetooth positioning tag first transmits data to a nearby Bluetooth gateway (installed at an appropriate location in the tunnel), and then the Bluetooth gateway forwards the data to the server in the monitoring center via Wi-Fi. It can not only use the low power consumption characteristics of Bluetooth for close-range data collection, but also use the high-speed transmission capability of Wi-Fi to reliably transmit data to the monitoring center for processing and analysis.

[0159] (III) Offline data processing, including the deployment of Bluetooth beacons, reference point selection, and fingerprint database establishment and optimization

[0160] (1) Reference point selection

[0161] Multiple reference points can be evenly selected in the shield tunnel to fully cover the different areas and environmental characteristics of the tunnel. The spacing between the reference points can be reasonably set according to the size and shape of the tunnel, generally between 5-10 meters.

[0162] When selecting reference points, various conditions in the tunnel can also be taken into consideration, including different geological conditions (such as rock layers, soil layers, etc.), construction equipment distribution, ventilation location, high-voltage electricity areas, equipment dangerous electricity and other factors, and reference electricity should be set at key locations. For example, reference points should be set in areas close to large construction equipment and in areas far away from the equipment, so as to accurately capture the characteristics of the signal in different environments.

[0163] (2) RSSI data collection and recording

[0164] At each reference point, a reference Bluetooth positioning tag (the reference Bluetooth positioning tag is used here to distinguish the interface from the Bluetooth positioning tag carried by the construction workers) is placed still for a period of time (for example, 3-5 minutes) to stably measure the RSSI values ​​of the surrounding Bluetooth beacons. During this period, the reference Bluetooth positioning tag performs multiple RSSI measurements on each visible Bluetooth beacon within the scanning range, and calculates the average value as the RSSI value of the beacon at the reference point.

[0165] At the same time, the position coordinate information of each reference point is recorded, such as the precise three-dimensional coordinates measured using a total station.

[0166] The RSSI value of each reference point and the position coordinates of the reference point are stored one by one to form an original fingerprint data set. For example, at the reference point with spatial coordinates (50, 3, 1.5), the RSSI values ​​of the three surrounding Bluetooth beacons are measured to be -65dBm, -70dBm, and -68dBm respectively. These values ​​are the RSSI values ​​after average processing. The RSSI values ​​of the three Bluetooth beacons are stored together with the coordinates of the reference point.

[0167] Thus, the initial fingerprint library is constructed.

[0168] In a further preferred embodiment, the collected original fingerprint data is processed and optimized to improve the quality of the fingerprint library and the positioning accuracy.

[0169] First, the stored RSSI values ​​(i.e., the values ​​after mean processing) are detected and removed for outliers. Statistical methods such as the 3σ criterion are used, that is, if a certain RSSI measurement value deviates from the RSSI average value of the reference point for the same beacon by more than 3 standard deviations, the measurement value is considered an outlier and is removed.

[0170] Then, the processed RSSI data is smoothed, for example, by using a Gaussian filter or other method to reduce noise interference in the data.

[0171] Finally, the processed RSSI value and position coordinates of each reference point are stored according to a certain data structure to build a fingerprint library.

[0172] As an optional method, a database management system (such as MySQL, Oracle, etc.) can be used to store the fingerprint library. The table structure can be designed to include fields: reference point ID, location coordinates (x, y, z), beacon ID1, RSSI1, beacon ID2, RSSI2, ... (determine the field according to the actual number of beacons). For example, in the fingerprint library, the fingerprint data of a reference point is recorded as follows: [reference point ID = 1, location coordinates, beacon ID1 = 001, RSSI1 = -65.2dBm, beacon ID2 = 002, RSSI2 = -69.8dBm, beacon ID3 = 003, RSSI3 = -67.5dBm].

[0173] (IV) Online monitoring stage

[0174] (1) When construction workers move in the tunnel with Bluetooth positioning tags, the Bluetooth positioning tags measure the RSSI values ​​of surrounding Bluetooth beacons in real time and perform multiple measurements and reports.

[0175] Among them, the Bluetooth positioning tags carried by the construction workers will package the measured Bluetooth beacon RSSI values ​​and beacon identification information, and send them to the Bluetooth beacon positioning system according to the reporting frequency. Each data packet contains the tag ID of the Bluetooth positioning tag, measurement time, beacon ID and the corresponding RSSI value.

[0176] The Bluetooth beacon positioning system receives the data packet reported by each construction worker's corresponding Bluetooth positioning tag and determines the RSSI value of each Bluetooth beacon measured by the construction worker's Bluetooth positioning tag by taking the average value of multiple measurements;

[0177] Similarly, the measured RSSI values ​​are subjected to outlier detection and filtering to remove obvious noise interference and abnormal data, in the same way as in the offline stage described above.

[0178] (2) The Bluetooth beacon positioning system uses the RSSI value of each Bluetooth beacon after mean processing corresponding to each construction worker as the real-time RSSI vector, and calculates the similarity between the real-time RSSI vector and the RSSI vector of each reference point in the fingerprint library. In this example, the Euclidean distance is used as an example:

[0179] Assume that the RSSI vector measured in real time is R:

[0180] R=[RSSI1,RSSI2,…,RSSI N ];

[0181] The RSSI vector of a reference point in the fingerprint database is R i :

[0182] R i =[RSSIi1 , RSSI i2 ,…,RSSI iN ];

[0183] Then the Euclidean distance d between them is calculated i Expressed as:

[0184]

[0185] Where N represents the number of Bluetooth beacons.

[0186] (3) According to the calculated Euclidean distance d i , determine the K reference points that are most similar to the real-time RSSI vector and calculate the weight of each of the K most similar reference points; K is generally between 3 and 6; in this example, 5 is used as an example, i.e., the 5 reference points with the smallest distance;

[0187] (4) According to the weight of each reference point, the estimated position of the construction personnel is determined based on the weighted average method as their real-time position coordinates in the limited space of the shield tunnel; in this example, the weight w is calculated for each selected reference point i , weight w i It can be determined according to the inverse of the similarity, that is:

[0188]

[0189] Then, for the weight w i Normalize it so that:

[0190]

[0191] Finally, the estimated position of the construction worker (x, y, z) is calculated using the weighted average method:

[0192]

[0193] Among them, (x i ,y i ,z i ) represents the position coordinates of the i-th selected reference point.

[0194] For example, if the Euclidean distances calculated for the selected 5 reference points are:

[0195] d1=2.5, d2=3.2, d3=2.8, d4=3.5, d5=2.6;

[0196] Their weights are:

[0197] ω1=1 / 2.5=0.4, ω2=1 / 3.2≈0.31, ω3=1 / 2.8≈0.36, ω4=1 / 3.5≈0.29, ω5=1 / 2.6≈0.38;

[0198] Furthermore, ω1~ω5 are normalized to obtain the normalized weights:

[0199] ””'

[0200] ω1≈0.24, ω2≈0.19, ω3≈0.22, ω4≈0.17, ω5≈0.22;

[0201] Therefore, according to the normalized weights ω1'~ω5' and the position coordinates of the five reference points, the x, y, and z values ​​of the position estimate are determined by weighted calculation respectively, so as to obtain the position estimate of the construction personnel as their real-time position coordinates in the limited space of the shield tunnel.

[0202] (V) Personnel safety warning

[0203] Based on the real-time position coordinates of the construction workers in the limited space of the shield tunnel, the movement status and safety warning of the construction workers are dynamically judged according to the temporal changes of the real-time position.

[0204] As in the aforementioned analysis and early warning method, for example, the motion state of the construction personnel can be determined by analyzing the position estimation value and its dynamic changes of the construction personnel. If the position coordinates of the construction personnel remain unchanged or the change value is within a preset range during multiple consecutive positioning cycles, then the construction personnel is determined to be in a stationary state; conversely, if the position coordinate changes exceed the preset range, then the construction personnel is determined to be in motion.

[0205] According to the different areas pre-divided within the limited space of the shield tunnel, the boundary coordinates of each area are pre-set; when the location coordinates of the construction personnel show that they enter or leave the preset specific area, the corresponding alarm is immediately issued, and the location and related information of the construction personnel are highlighted on the screen of the monitoring center.

[0206] The time construction workers stay in each area is recorded. When a construction worker stays in a specific area for longer than the system safety threshold, an early warning message is issued to remind management personnel or the nearest construction worker to pay attention to whether the worker encounters difficulties or abnormal situations, and the location and related information of the construction worker are highlighted on the screen of the monitoring center.

[0207] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A shield tunnel limited space safety operation protection warning system, characterized in that: include: RFID tags carried by shield tunnel construction workers, each RFID tag corresponds to a construction worker one by one; The Bluetooth positioning tags integrated into the helmets worn by construction workers, each Bluetooth positioning tag corresponds to a construction worker one by one; The identity management server is configured to store the identity ID of each construction worker and the facial features, RFID tag information, Bluetooth positioning tag information and construction area information associated with the identity ID; The environmental monitoring system arranged in the limited space of the shield tunnel is equipped with multiple sensor components for monitoring the temperature, humidity and air quality in the limited space of the shield tunnel; A Bluetooth beacon system deployed in a limited space of a shield tunnel, wherein the Bluetooth beacon system includes a plurality of Bluetooth beacons, each of which has a beacon ID as a unique identifier and a coordinate value in a Cartesian coordinate system established with an entrance of the shield tunnel as an origin; A UHF card reader is installed at the entrance of the shield tunnel to read the RFID tags carried by construction workers entering the shield tunnel to preliminarily locate the identity of the construction workers; A face recognition system is set up at the entrance of the shield tunnel to collect face images, perform face recognition and registration on construction workers who enter the limited space of the shield tunnel through the entrance, and count the total number of construction workers who enter the limited space of the shield tunnel; Environmental safety early warning system, which is used to issue construction early warnings based on real-time monitoring of temperature, humidity and air quality and safety threshold ranges; A fingerprint library based on RSSI, used to store fingerprint data of multiple selected reference points in the limited space of the shield tunnel, each fingerprint data includes a coordinate value of the reference point in the Cartesian coordinate system and its corresponding RSSI value; A Bluetooth beacon positioning system is connected to the Bluetooth beacon system and the RSSI-based fingerprint library; the Bluetooth beacon positioning system is configured to estimate the position of each construction worker in the limited space of the shield tunnel and its dynamic changes based on the RSSI values ​​of the Bluetooth beacons located around it scanned by the Bluetooth positioning tag and the fingerprint data of multiple reference points in the fingerprint library; The personnel safety warning system is connected to the Bluetooth beacon positioning system and is configured to issue warnings based on the position of each construction worker in the limited space of the shield tunnel and its changing state.

2. The shield tunnel limited space safety operation protection warning system according to claim 1 is characterized in that: The RFID tag and Bluetooth positioning tag assigned to each construction worker are integrated into the safety helmet worn by the construction worker, and establish a one-to-one correspondence with the construction worker's identity ID.

3. The shield tunnel limited space safety operation protection warning system according to claim 1 is characterized in that: The UHF card reader is configured to determine the identity of the construction personnel within the antenna radiation field of the UHF card reader by reading the RFID tags carried by the construction personnel entering the shield tunnel for operation, and store the corresponding construction personnel identity information in a cache according to the identity of the construction personnel corresponding to the read RFID tags.

4. The shield tunnel limited space safety operation protection warning system according to claim 3 is characterized in that: The face recognition system includes a camera for acquiring face images and an edge computing system for performing identity recognition based on the face images of construction workers collected by the camera. The edge computing system performs 1:1 face recognition based on the collected face images of construction workers and the identity information of construction workers stored in the cache library, determines the identities of construction workers entering the construction area, registers and counts them, and summarizes the total number of construction workers entering the limited space of the shield tunnel.

5. The shield tunnel limited space safety operation protection warning system according to claim 1 is characterized in that: The RSSI-based fingerprint library is configured to be constructed by selecting reference points offline and collecting and recording RSSI data of the reference points, wherein: Starting from the entrance of the shield tunnel and extending to the construction area within the limited space of the shield tunnel, reference points are set in a way that the adjacent reference points are spaced at preset intervals, and reference points are configured for ventilation openings, boundary locations of different geological conditions, construction equipment locations, tunnel boundaries, and high-voltage power areas; For each reference point, a reference Bluetooth positioning tag is used to stand still and measure the RSSI values ​​of the Bluetooth beacons around it. The reference Bluetooth positioning tag performs multiple RSSI measurements on each visible Bluetooth beacon within its scanning range, and calculates the average value as the RSSI value of the reference point for a certain Bluetooth beacon; For each reference point, record its coordinate value in the Cartesian coordinate system; The coordinate value of each reference point and the RSSI value of the Bluetooth beacon corresponding to each reference point are stored one by one to construct an initial fingerprint library.

6. The shield tunnel limited space safety operation protection warning system according to claim 5 is characterized in that: By performing outlier detection and elimination and Gaussian smoothing on the initial fingerprint library, a final fingerprint library is obtained, which is used to estimate the position of construction personnel in the limited space of the shield tunnel and its dynamic changes.

7. The shield tunnel limited space safety operation protection warning system according to claim 5 is characterized in that: The Bluetooth beacon positioning system is configured to estimate the position of each construction worker in the limited space of the shield tunnel according to the RSSI value of the Bluetooth beacon located around the Bluetooth positioning tag and the fingerprint data of multiple reference points in the fingerprint library, including: When construction workers carry Bluetooth positioning tags and move in the limited space of a shield tunnel, the Bluetooth positioning tags measure the RSSI values ​​of the surrounding Bluetooth beacons in real time and report them to the Bluetooth beacon positioning system according to a predetermined period; The Bluetooth beacon positioning system determines the RSSI value of each Bluetooth beacon measured by the construction worker's Bluetooth positioning tag by taking the average value of multiple measurements; The Bluetooth beacon positioning system matches the RSSI value of each Bluetooth beacon corresponding to each construction worker after mean processing with the fingerprint data in the fingerprint library, estimates the real-time location of each construction worker, and dynamically determines the movement status and safety warning of the construction worker based on the time series changes of the real-time location.

8. The shield tunnel limited space safety operation protection warning system according to claim 7 is characterized in that: The Bluetooth beacon positioning system estimates the real-time location of each construction worker by matching the RSSI value of each Bluetooth beacon after mean processing corresponding to each construction worker with the fingerprint data in the fingerprint library, including: The RSSI value of each Bluetooth beacon corresponding to each construction worker after mean processing is used as the real-time RSSI vector. The similarity between the real-time RSSI vector and the RSSI vector of each reference point in the fingerprint library is calculated, and the Euclidean distance, Manhattan distance or cosine similarity is used as the similarity metric; According to the calculated similarity, determine the K reference points that are most similar to the real-time RSSI vector; Calculate the weight of each reference point among the most similar K reference points; According to the weight of each reference point, the position estimate of the construction worker is determined based on the weighted average method as his real-time position coordinates in the limited space of the shield tunnel.

9. The shield tunnel limited space safety operation protection warning system according to claim 7 is characterized in that: The dynamic judgment of the movement status of construction personnel and safety warning based on the time series change of real-time position includes: The motion state of the construction personnel is determined by analyzing the estimated position value of the construction personnel and its dynamic changes. If the position coordinates of the construction personnel remain unchanged or the change value is within the preset amplitude range during multiple consecutive positioning cycles, the construction personnel is determined to be in a stationary state; conversely, if the position coordinates change beyond the preset amplitude range, the construction personnel is determined to be in a moving state; According to the different areas pre-divided in the limited space of the shield tunnel, the boundary coordinates of each area are pre-set; when the location coordinates of the construction personnel show that they enter or leave the preset specific area, the corresponding alarm is immediately issued, and the location and related information of the construction personnel are highlighted on the screen of the monitoring center; The construction workers' stay time in each area is recorded. When the construction workers stay in a specific area for longer than the system safety threshold, an early warning message is issued to remind the management staff or the construction workers closest to them to pay attention to whether the personnel encounter difficulties or abnormal situations, and the location and related information of the construction workers are highlighted on the screen of the monitoring center.

10. The shield tunnel confined space safety operation protection warning method of the shield tunnel confined space safety operation protection warning system according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Complete Bluetooth beacon deployment, reference point selection, and fingerprint database establishment in the offline phase, including the following operations: Step 1.1, multiple Bluetooth beacons are arranged according to the construction area and construction length, each Bluetooth beacon has a beacon ID as a unique identifier, and a coordinate value in a Cartesian coordinate system established with the shield tunnel entrance as the origin; the Bluetooth beacons are installed at a distance of 10 to 20 meters in a manner extending inward from the shield tunnel entrance, and the installation height of the Bluetooth beacons is 1.5 to 2.5 meters; when installing each Bluetooth beacon, the position coordinates thereof are accurately measured and recorded by a measuring instrument, that is, the coordinate values ​​in a Cartesian coordinate system established with the shield tunnel entrance as the origin; Step 1.2: Test and configure the transmit power and broadcast frequency of the Bluetooth beacon; Step 1.3, starting from the entrance of the shield tunnel and extending to the construction area within the limited space of the shield tunnel, set reference points in a way that the adjacent reference points are spaced at preset intervals, and configure reference points for ventilation openings, boundary positions of different geological conditions, construction equipment positions, tunnel boundaries, and high-voltage power areas; Step 1.4: For each reference point, use a reference Bluetooth positioning tag to stand still and measure the RSSI values ​​of the Bluetooth beacons around it. The reference Bluetooth positioning tag performs multiple RSSI measurements on each visible Bluetooth beacon within its scanning range, and calculates the average value as the RSSI value of the reference point for a Bluetooth beacon. Step 1.5: For each reference point, record its coordinate value in the Cartesian coordinate system, and store the coordinate value of each reference point and the RSSI value of the Bluetooth beacon corresponding to each reference point in a one-to-one correspondence to construct an initial fingerprint library. Step 1.6, performing outlier detection and elimination and Gaussian smoothing processing on the initial fingerprint library to obtain a final fingerprint library for estimating the position of construction personnel in the limited space of the shield tunnel and its dynamic changes; (2) Online real-time monitoring of the movement status of construction workers and safety warnings, including the following operations: Step 2.1, when the construction workers move in the limited space of the shield tunnel, the Bluetooth positioning tag they carry packages the measured Bluetooth beacon RSSI value and beacon identification information, and sends it to the Bluetooth beacon positioning system according to the reporting frequency. Each data packet contains the tag ID of the Bluetooth positioning tag, the measurement time, the beacon ID and the corresponding RSSI value; Step 2.2, the Bluetooth beacon positioning system receives the data packet reported by the Bluetooth positioning tag corresponding to each construction worker, and determines the RSSI value of each Bluetooth beacon measured by the Bluetooth positioning tag of the construction worker by taking the average value of multiple measurements; Step 2.3, the Bluetooth beacon positioning system uses the RSSI value of each Bluetooth beacon corresponding to each construction worker after mean processing as the real-time RSSI vector, calculates the similarity between the real-time RSSI vector and the RSSI vector of each reference point in the fingerprint library, and uses Euclidean distance, Manhattan distance or cosine similarity as the similarity metric; Step 2.4, according to the calculated similarity, determine the K reference points that are most similar to the real-time RSSI vector and calculate the weight of each reference point in the K most similar reference points; Step 2.5, according to the weight of each reference point, determine the estimated position value of the construction personnel based on the weighted average method as the real-time position coordinate of the construction personnel in the limited space of the shield tunnel; Step 2.6: Dynamically determine the movement status of the construction personnel and issue safety warnings based on the time series changes of the construction personnel's real-time positions.

11. The shield tunnel limited space safety operation protection early warning method according to claim 10 is characterized in that: The method of dynamically judging the movement state of the construction personnel and providing safety warnings according to the time series changes of the real-time positions of the construction personnel includes: The motion state of the construction personnel is determined by analyzing the estimated position value of the construction personnel and its dynamic changes. If the position coordinates of the construction personnel remain unchanged or the change value is within the preset amplitude range during multiple consecutive positioning cycles, the construction personnel is determined to be in a stationary state; conversely, if the position coordinates change beyond the preset amplitude range, the construction personnel is determined to be in a moving state; According to the different areas pre-divided in the limited space of the shield tunnel, the boundary coordinates of each area are pre-set; when the location coordinates of the construction personnel show that they enter or leave the preset specific area, the corresponding alarm is immediately issued, and the location and related information of the construction personnel are highlighted on the screen of the monitoring center; The construction workers' stay time in each area is recorded. When the construction workers stay in a specific area for longer than the system safety threshold, an early warning message is issued to remind the management staff or the construction workers closest to them to pay attention to whether the personnel encounter difficulties or abnormal situations, and the location and related information of the construction workers are highlighted on the screen of the monitoring center.

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