Card punching method and system based on multifunctional safety helmet UWB high-precision positioning

Abstract

The invention discloses a card punching method and system based on multifunctional safety helmet UWB high-precision positioning, and the method comprises the steps: deploying at least three UWB positioning base stations in a preset card punching region, and enabling each base station to be in communication connection with a background server; detecting the moving state of a person based on an acceleration sensor, and dynamically adjusting the ranging frequency of the UWB tag; when a person enters a card punching area, distance measurement data are interacted with at least three UWB positioning base stations according to the current frequency through a UWB tag and are sent to a background server, the distance measurement data are preprocessed by adopting Kalman filtering, and then the real-time position is calculated through a triangulation positioning algorithm to judge whether the person is in an effective card punching area or not; if the position is valid, verifying correct wearing of the safety helmet based on the wearing detection sensor; and matching the tag identifier with the personnel identity through the background server, and generating and storing a card punching record. The method is used for solving the technical problems of insufficient precision, lack of safety compliance, unbalanced power consumption and identity matching distortion of the existing card punching technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of personnel positioning and safety management, in particular to a clock-in method and system based on UWB high-precision positioning of a multifunctional safety helmet. BACKGROUND

[0002] In high-risk operation scenarios such as construction, mining, and chemical park, personnel attendance management and safety compliance monitoring are the core of enterprise operation. Existing clock-in technologies have many limitations and cannot meet the requirements of high precision, high safety, and high reliability, as follows: (1) Limitations of contact clock-in technology Fingerprint, face recognition, and IC card clock-in rely on fixed terminals and can only be completed at designated locations, making it impossible to achieve dynamic clock-in within a preset area. They are easy to be forged (such as fingerprint film and face photo) leading to clock-in by proxy, and cannot verify the safety helmet wearing status, which is inconsistent with the safety specifications of high-risk operations.

[0003] (2) Defects of non-contact positioning clock-in GPS positioning has low accuracy and severe indoor signal attenuation, which cannot meet the clock-in requirements in small areas. RFID clock-in has short recognition distance and poor accuracy, lacks dynamic power adjustment mechanism, and has weak device endurance. Neither of them integrates safety helmet wearing detection, making it difficult to ensure safety compliance.

[0004] (3) Defects of ordinary UWB positioning clock-in Existing UWB solutions do not dynamically adjust the ranging frequency according to the personnel movement state, resulting in high power consumption when stationary or insufficient accuracy when moving. The base station deployment does not strictly follow the geometric conditions of triangular positioning (such as collinear deployment), leading to increased positioning error. It lacks infrared + pressure sensor dual wearing verification, making it impossible to accurately determine the safety helmet wearing status. The identity matching mechanism is imperfect, and the tag may be separated from the personnel, leading to distorted clock-in records. SUMMARY

[0005] To overcome the deficiencies of existing technologies, the present application aims to provide a clock-in method and system based on UWB high-precision positioning of a multifunctional safety helmet, which solves the technical problems of insufficient accuracy, lack of safety compliance, unbalanced power consumption, and identity matching distortion in existing clock-in technologies in high-risk operation scenarios.

[0006] To solve the above problems, the technical solution adopted by the present application is as follows: A clock-in method based on UWB high-precision positioning of a multifunctional safety helmet, comprising the following steps: Deploy at least three UWB positioning base stations in a preset clock-in area, and establish communication connections between each base station and the background server; Detecting the moving state of the personnel based on the acceleration sensor through the microprocessor, and dynamically adjusting the ranging frequency of the UWB tag; When the personnel enters the clock-in area, the UWB tag and at least three UWB positioning base stations interact with the ranging data at the current frequency, and send the data to the background server; The background server preprocesses the ranging data by Kalman filtering, and calculates the real-time position by the triangulation algorithm to determine whether it is in the effective clock-in area; If the position is valid, the microprocessor verifies the correct wearing of the safety helmet based on the wearing detection sensor; The background server matches the tag identification with the personnel identity, associates the real-time position and personnel state to generate and store the clock-in record.

[0007] Preferably, when deploying at least three UWB positioning base stations, it includes: Calibrating the time synchronization of all UWB positioning base stations to control the calibration error within a preset threshold; Among them, the deployment positions of the at least three UWB positioning base stations satisfy the geometric conditions of triangulation: any three base stations are not on the same straight line, and cover the entire effective range of the preset clock-in area.

[0008] Preferably, when establishing a communication connection between each base station and the background server, it includes: Each UWB positioning base station uses wired or wireless communication protocol to establish a bidirectional data transmission link with the background server; Each UWB positioning base station uploads its unique identification ID, deployment position coordinates and hardware initial state parameters to the background server to complete identity registration; The background server verifies the registration information of the base station, and feeds back a connection success confirmation instruction to the base station after verification, and stores the base station information to the database; After establishing the communication connection, the link stability is detected periodically, and if the connection is interrupted, the automatic reconnection mechanism is triggered, and the abnormal log is recorded to the background server.

[0009] Preferably, when detecting the moving state of the personnel based on the acceleration sensor, it includes: The microprocessor collects the three-axis acceleration data output by the acceleration sensor in real time at a preset sampling frequency; The collected three-axis acceleration data is subjected to low-pass filtering processing; The modulus of the filtered three-axis acceleration data is calculated and compared with the preset static threshold and moving threshold; If the modulus is lower than the static threshold for a continuous preset number of times, it is determined to be a static state; if it is higher than the moving threshold for a continuous preset number of times, it is determined to be a moving state.

[0010] Preferably, when dynamically adjusting the ranging frequency of the UWB tag, it includes: When it is determined to be a stationary state, the ranging frequency of the UWB tag is gradually reduced from the current value to a preset first frequency through the microprocessor control; When it is determined to be a moving state, the ranging frequency of the UWB tag is gradually increased from the current value to a preset second frequency through the microprocessor control; Wherein, the step length of frequency adjustment is a preset value, and the preset first frequency and the preset second frequency can be remotely configured by the background server.

[0011] Preferably, when interacting with the ranging data at the current frequency, it includes: The UWB tag sends a ranging request signal containing its own unique identification ID to each base station, and the base station returns a response signal containing its own unique identification ID and a timestamp after receiving it; the timestamp is based on the time synchronization calibration result; During the interaction of the ranging data, the stability of the interaction link is periodically detected; if the link stability is lower than a preset threshold, an automatic reconnection mechanism is triggered, and abnormal information is recorded to the background server; Wherein, the ranging request signal contains the current moving state identifier, and the base station processes the high frequency ranging request in the moving state preferentially after receiving it.

[0012] Preferably, when determining whether it is in the valid area of clock-in, it includes: The original ranging data obtained by the UWB tag and each base station through interaction is smoothed one by one by using the Kalman filter algorithm through the background server; Based on the pre-registered position coordinates of at least three UWB positioning base stations and the filtered distance values, the real-time three-dimensional coordinates of the UWB tag are solved by the trilateration method; if it is a two-dimensional positioning scene, the two-dimensional coordinates are calculated; The real-time position coordinates are substituted into the area judgment logic by calling the pre-stored clock-in valid area boundary parameters through the background server, to verify whether it is in the valid area; If the real-time position is continuously determined to be in the valid area for M times, and the time interval between the adjacent two determinations is ≤ a preset threshold, it is confirmed that the current position is valid; otherwise, it is determined to be invalid; If the number of effective base stations participating in the calculation is less than three, the position calculation is suspended, the abnormal log is recorded and the ranging data supplementing mechanism is triggered, and after obtaining the effective ranging data of at least three base stations, the position validity is reconfirmed.

[0013] Preferably, when verifying the correct wearing of the safety helmet based on the wearing detection sensor, it includes: Verify whether the infrared sensor continuously detects the head shielding signal, and the fitting pressure value collected by the pressure sensor is ≥ a preset threshold; When the above two conditions are met at the same time and last for a preset duration, it is determined as a correct wearing state; If the correct wearing state is not detected, the microprocessor prohibits sending a clock-in request to the background server.

[0014] Preferably, when matching the tag identifier and the personnel identity through the background server, the following steps are included: After receiving the unique identifier ID of the UWB tag through the background server, the pre-established tag-personnel association database is accessed; If there is a valid association record corresponding to the identifier ID in the tag-personnel association database, the personnel identity information is extracted to complete the matching; if there is no valid association record or the association record is invalid, an identity verification exception is triggered, an alarm information is sent to the administrator, and an exception log is recorded; The tag-personnel association database stores a one-to-one correspondence between the unique identifier ID of the UWB tag and the personnel identity information. When associating the real-time location and the personnel state to generate a clock-in record and store it, the following steps are included: The personnel identity information, real-time positioning data, state data, and event metadata are integrated into a standardized clock-in record by the background server, and the standardized clock-in record is stored in JSON format.

[0015] A clock-in system based on UWB high-precision positioning of a multifunctional safety helmet adopts the clock-in method described above, and includes: At least three UWB positioning base stations are deployed in a preset clock-in area and establish a bidirectional communication connection with the background server. A multifunctional safety helmet integrates a UWB tag, a wearing detection sensor, an acceleration sensor, and a microprocessor; the microprocessor is electrically connected with each component; the microprocessor detects the movement state of the personnel based on the acceleration sensor data, dynamically adjusts the ranging frequency of the UWB tag, and verifies whether the signal of the wearing detection sensor meets the correct wearing condition. A background server receives the ranging data uploaded by the UWB positioning base station, calculates the real-time position of the UWB tag through a triangular positioning algorithm after preprocessing by a Kalman filter, judges whether the real-time position is in a clock-in valid area, receives the wearing verification result of the microprocessor if it is valid, matches the unique identifier ID of the UWB tag with the personnel identity information, and associates the real-time position and the personnel state to generate a standardized clock-in record and store it.

[0016] Compared with the prior art, the present application has the following advantages: (1) High-precision dynamic positioning Adopting UWB time-of-flight (TOF) ranging technology, combined with base station time synchronization calibration (error ≤ 1 ns) and triangular positioning geometry deployment (non-collinear, full-area coverage), the positioning accuracy is high, meeting the requirements of high-risk operation scenarios for position accuracy; through Kalman filter preprocessing of ranging data, environmental interference is eliminated, further improving the stability of position calculation.

[0017] (2) Dynamic power balance Intelligently adjust the UWB tag ranging frequency according to the personnel movement state (stillness / movement): reduce to 0.5-2Hz to save power when still, and increase to 5-20Hz to ensure real-time when moving; frequency smooth transition (step control) avoids power fluctuations, and background remote configuration function adapts to different scene needs, effectively extending the safety hat battery life.

[0018] (3) Safety compliance verification Dual-wearing detection integrated with infrared + pressure sensor: head blocking signal continuous detection, adhesion pressure ≥ threshold and continuous for a preset period of time are required to ensure that personnel wear safety hats in a real and standard manner, preventing fake clock-in or non-compliant wearing; prohibit sending clock-in requests when wearing verification fails, ensuring that safety management is implemented from the source.

[0019] (4) Reliable identity matching and anti-cheating Establish a tag-personnel association database to realize one-to-one mapping of UWB tag ID and personnel identity (name, ID, position), ensuring that the clock-in record is "person and certificate in one"; trigger abnormal alarm and record logs for unknown tags or invalid association records, facilitating traceability and management, and preventing false clock-in.

[0020] (5) System robustness and stability Bidirectional communication link between base station and server supports wired / wireless protocol, periodically detects link stability and automatically reconnects; Abnormal data processing mechanism (such as suspending calculation and supplementing data when the number of base stations is insufficient) ensures continuous operation of the system in complex environments; Standardized JSON format for storing clock-in records, including personnel identity, positioning data, state information and metadata, improving cross-system interoperability and traceability.

[0021] (6) Strong scene adaptability Support for three-dimensional / two-dimensional positioning scene switching to adapt to different high-risk operation environments indoors and outdoors; Background remote configuration function (frequency, area boundary, etc.) can quickly respond to changes in the scene, reducing operation and maintenance costs.

[0022] In conclusion, the application realizes an integrated clock-in solution of "high-precision positioning + safety compliance + low power consumption + reliable recording", and provides efficient and safe technical support for personnel management in high-risk operation scenarios.

[0023] The application will be described in further detail below with reference to the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a clock-in method step diagram based on UWB high-precision positioning of the multifunctional safety helmet according to an embodiment of the application; Figure 2 is a communication connection establishment flowchart according to an embodiment of the application; Figure 3 is a clock-in effective area judgment flowchart according to an embodiment of the application; Figure 4 is a clock-in system module interaction diagram based on UWB high-precision positioning of the multifunctional safety helmet according to an embodiment of the application.

[0025] The reference signs in the drawings are explained as follows: 21, UWB positioning base station; 22, multifunctional safety helmet; 221, UWB tag; 222, wearing detection sensor; 223, acceleration sensor; 224, microprocessor; 23, background server. DETAILED DESCRIPTION

[0026] Exemplary embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0027] It should be understood that the dimensions of the various parts shown in the drawings are not drawn to scale for the sake of convenience of description.

[0028] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application or its application or uses.

[0029] Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail herein, but should be considered as part of the specification in appropriate circumstances.

[0030] Embodiment 1, refer to Figure 1 the clock-in method step diagram, the application provides a clock-in method based on UWB high-precision positioning of the multifunctional safety helmet as shown in Figure 1 The clock-in method based on UWB high-precision positioning of the multifunctional safety helmet comprises the following steps: S1. Deploy at least three UWB positioning base stations 21 in the preset punch-in area, and establish a communication connection between each base station and the background server 23; S2. Detect the movement state of the personnel based on the acceleration sensor 223 through the microprocessor 224, and dynamically adjust the ranging frequency of the UWB tag 221: reduce to a preset first frequency (low frequency) when stationary, and increase to a preset second frequency (high frequency) when moving; S3. When the personnel enter the punch-in area, interact with the at least three UWB positioning base stations 21 at the current frequency through the UWB tag 221 to measure the ranging data, and send it to the background server 23; S4. Preprocess the ranging data by Kalman filtering through the background server 23, and then calculate the real-time position by a triangulation algorithm to determine whether it is in the valid punch-in area; S5. If the position is valid, verify the correct wearing of the safety helmet based on the wearing detection sensor 222 through the microprocessor 224; S6. Match the tag identification with the personnel identity through the background server 23, associate the real-time position, personnel state to generate a punch-in record and store it; Among them, the multifunctional safety helmet 22 integrates the UWB tag 221, the wearing detection sensor 222, the acceleration sensor 223 and the microprocessor 224, and the microprocessor 224 is electrically connected with each component respectively.

[0031] In the embodiments of the present application, it needs to be further explained that step S1 provides a hardware basis and a data transmission link for positioning, ensuring the accuracy of subsequent ranging and positioning. Step S2 balances the positioning accuracy and device power consumption, reduces the ranging frequency to save power when stationary, and increases the frequency to ensure real-time when moving. Step S3 obtains the distance data between the tag and the base station, providing the original input for positioning calculation. Step S4 extracts the accurate position from the original ranging data to determine whether it is in the valid punch-in area. Step S5 ensures that the punch-in personnel truly wear the safety helmet, preventing card punching or non-standard wearing. Step S6 associates the tag with the personnel identity to generate a standardized punch-in record and store it.

[0032] BACKGROUND DESCRIPTION: The core of UWB positioning technology relies on the time of flight (TOF) ranging principle: by calculating the propagation time of the UWB signal from the tag (safety helmet integrated) to the base station, the distance between them is obtained by multiplying the speed of light. The accuracy of the propagation time directly determines the distance measurement accuracy, and time synchronization is a key prerequisite for ensuring the correctness of the propagation time calculation - if the time of the base stations is not synchronized, the timestamp error of the signal sending and receiving will directly translate into distance error (e.g. 1ns error corresponds to about 0.3m distance deviation).

[0033] In addition, the UWB positioning adopts a trilateration method to solve the tag position: at least three base stations with known coordinates are needed, the distances from the tag to each base station are used, and the real-time position of the tag is derived through geometric operation. If the three base stations are on the same straight line, the position solving of the tag will have ambiguity (such as unable to determine the coordinates perpendicular to the straight line direction) or error significantly increases, which cannot meet the requirements of the position accuracy in the clock-in scene. Based on this: In the above step S1, when deploying at least three UWB positioning base stations 21 in the preset clock-in area, it includes: Calibrate the time synchronization of all UWB positioning base stations 21, control the calibration error within a preset threshold (such as 1ns level), to ensure the time consistency of the ranging data and improve the positioning accuracy; Among them, the deployment positions of the at least three UWB positioning base stations 21 satisfy the geometric conditions of triangular positioning: any three base stations are not on the same straight line, and cover the entire effective range of the preset clock-in area, to ensure that personnel entering the area can be detected by at least three base stations at the same time.

[0034] In the embodiments of the present application, it is further explained that step S1 requires that the calibration error be controlled within a preset threshold (such as 1ns level), and that the time consistency of the ranging data be ensured by a small time synchronization error, to provide a basic support for subsequent high-precision positioning. At the same time, the base station deployment needs to satisfy the geometric conditions of "any three non-collinear" and "full area coverage", to provide a reliable spatial foundation for the triangular positioning algorithm.

[0035] Referring to Figure 2 the communication connection establishment flowchart, in the above step S1, when establishing a communication connection between each base station and the background server 23, it includes: Each UWB positioning base station 21 uses wired or wireless communication protocols (such as Ethernet, Wi-Fi, LoRaWAN) to establish a bidirectional data transmission link with the background server 23, to ensure the real-time and reliability of the ranging data and the base station state information; Each UWB positioning base station 21 uploads its unique identification ID, deployment position coordinates and hardware initial state parameters to the background server 23, to complete the identity registration; The background server 23 verifies the registration information of the base station (including the uniqueness of the identification, the rationality of the position coordinates), feeds back a connection success confirmation instruction to the base station after verification, and stores the base station information to the database, to provide basic data support for subsequent triangular positioning calculation; After establishing the communication connection, the link stability is periodically detected, if the connection is interrupted, the automatic reconnection mechanism is triggered, and the abnormal log is recorded to the background server 23, to ensure the continuous operation of the system.

[0036] To be further explained in the embodiments of the present application, the core of the UWB high-precision positioning clock-in method is to realize real-time position calculation of the tag (safety helmet integrated) through time of flight (TOF) ranging and trilateration, and the communication connection between the base station and the background server 23 is the key infrastructure supporting this process. The necessity of each sub-step is explained from the overall demand as follows: 1. Selection of bidirectional data transmission link and real-time requirement UWB positioning relies on the accurate calculation of signal propagation time between the tag and the base station (1 ns error corresponds to about 0.3 meter distance deviation), so the real-time of ranging data directly determines the positioning accuracy. At the same time, the background server 23 needs to issue instructions to the base station (such as time synchronization calibration, frequency configuration update), and the base station needs to upload its own state (such as hardware failure, signal strength), so a bidirectional link needs to be established. Wired (Ethernet) is suitable for fixed scenarios (such as indoor office area), and wireless protocols (Wi-Fi, LoRaWAN) are suitable for mobile environments such as outdoor construction area, to ensure the reliability of data transmission in different scenarios.

[0037] 2. Positioning basic requirement of base station identity registration The trilateration algorithm needs to know the accurate coordinates and unique identification of at least three base stations to calculate the tag position. If the base station is not registered or the information is incorrect, it will lead to: Duplicate identification: the background cannot distinguish different base stations, and the ranging data is confused; Incorrect position coordinates: the tag position calculation result deviates from the actual value (such as the base station coordinates are mistakenly set outside the clock-in area).

[0038] Therefore, the base station must upload the unique ID, deployment coordinates and hardware parameters to complete the identity registration and provide basic data support for subsequent positioning calculation.

[0039] 3. Accuracy guarantee of registration information verification The verification of base station information by the background server 23 (identification uniqueness, position rationality) is the key to exclude incorrect data: Verification of identification uniqueness: avoid using the same ID for multiple base stations to prevent data conflict; Verification of position rationality: ensure that the base station coordinates meet the geometric conditions of trilateration (such as not on the same straight line, cover the clock-in area), and not exceed the physical scene range (such as abnormal large coordinate value).

[0040] After verification, store it in the database to ensure that the subsequent positioning calculation calls the reliable base station data.

[0041] 4. System availability requirement of link stability detection The UWB positioning system needs to run continuously 24 / 7 (such as construction workers clocking in all day), if the base station and the background connection is interrupted, it will cause the ranging data loss, positioning failure. Periodic detection of link stability can discover problems in time, automatic reconnection mechanism ensures the system to recover quickly, abnormal log record helps the administrator to trace the fault cause (such as network fluctuation, hardware failure), ensures the long-term reliable operation of the system.

[0042] In the above step S2, when the microprocessor 224 detects the personnel movement state based on the acceleration sensor 223, it includes: The microprocessor 224 collects the three-axis acceleration data output by the acceleration sensor 223 in real time at a preset sampling frequency (such as 100Hz); The collected three-axis acceleration data is subjected to low-pass filtering processing to eliminate noise interference such as environmental vibration; The modulus value of the filtered three-axis acceleration data is calculated and compared with a preset stationary threshold (such as 0.1g) and a moving threshold (such as 0.5g); If the modulus value is continuously below the stationary threshold for a preset number of times (such as 5 times), it is determined to be a stationary state; if it is continuously higher than the moving threshold for a preset number of times (such as 3 times), it is determined to be a moving state.

[0043] In the embodiments of the present application, it needs to be further explained that this step is a key pre-step for dynamically balancing positioning accuracy and device power consumption, and its design closely serves the practicality and efficiency of the overall clocking process, with the following specific background: I. Core role: provide basis for dynamic adjustment of UWB ranging frequency The accuracy of UWB positioning is positively related to the ranging frequency (high-frequency ranging can improve the real-time performance of position updating), but the power consumption also increases with the increase of frequency. As a portable device, the multi-functional safety helmet 22 is a key indicator of endurance. Therefore, by sensing the personnel motion state, the ranging frequency is intelligently switched - high frequency is used to ensure positioning accuracy when moving, and low frequency is used to reduce power consumption when stationary. This step is the basis for this intelligent adjustment.

[0044] II. Background design of technical principle 1. Three-axis acceleration data acquisition The acceleration sensor 223 captures the acceleration changes in X / Y / Z three directions to reflect the motion state of the personnel (such as walking, standing). The design of a preset 100Hz sampling frequency is to capture the subtle changes in the motion state in real time, avoiding state judgment lag due to too long sampling interval (such as missing the start signal of rapid movement).

[0045] 2. Low-pass filtering processing There are a lot of environmental vibrations (such as machinery operation, ground bumping) in the scene of construction site, workshop, etc. These noises will interfere with the accuracy of acceleration data. Low-pass filtering can filter high-frequency noise and only keep low-frequency signals related to personnel movement, ensuring that the data reflects the true movement state rather than environmental interference.

[0046] 3. Modulus calculation and threshold comparison Combining three-axis acceleration data into a modulus value can simplify state judgment logic (no need to analyze three axes separately). The pre-set static threshold (0.1g) and moving threshold (0.5g) are based on empirical values in actual scenarios: When stationary, personnel have no active movement, and acceleration changes very little (modulus value below 0.1g); When moving, limb movements produce significant acceleration (modulus value above 0.5g).

[0047] 4. Continuous number judgment The introduction of "continuous preset number" (5 times stationary / 3 times moving) judgment logic is to avoid misjudgment caused by instantaneous shaking: For example, a brief collision on a construction site may cause the modulus value to exceed the moving threshold momentarily, but it is not sustained movement; Continuous number verification can ensure the stability of state judgment and improve system reliability.

[0048] III. Association with the overall clock-in plan The output of this step directly affects the subsequent process: If it is determined to be a moving state, the UWB tag 221 switches to high-frequency ranging (5-20Hz) to ensure the position update speed when entering the clock-in area, meeting the high-precision requirements of clock-in; If it is determined to be a stationary state, switch to low-frequency ranging (0.5-2Hz) to significantly reduce the power consumption of the safety helmet and extend the battery life (especially suitable for long stationary scenarios such as construction site offices).

[0049] At the same time, all processing is done on the local microprocessor 224 of the safety helmet, without relying on the background server 23, reducing data transmission delay and ensuring the real-time nature of frequency adjustment.

[0050] In summary, step S2 achieves intelligent adaptation of UWB ranging frequency through precise and efficient motion state detection.

[0051] In the above step S2, when dynamically adjusting the ranging frequency of the UWB tag 221, it includes: When it is determined to be a stationary state, the microprocessor 224 controls the UWB tag 221 to gradually reduce the ranging frequency from the current value to a pre-set first frequency (such as 0.5Hz~2Hz); When the moving state is determined, the UWB tag 221 is controlled by the microprocessor 224 to gradually increase the ranging frequency from the current value to a preset second frequency (such as 5 Hz-20 Hz); The step length of the frequency adjustment is a preset value (such as 0.5 Hz / time), which avoids sudden changes that cause power consumption fluctuations or data loss; The preset first frequency and the preset second frequency can be remotely configured by the background server 23: After receiving the frequency parameters input by the administrator through the background server 23, the UWB positioning base station 21 sends an update instruction to the UWB tag 221; After receiving the instruction through the microprocessor 224, the corresponding frequency parameter is updated in real time to adapt to the positioning accuracy and power consumption requirements of different scenes (such as indoor office areas and outdoor construction areas).

[0052] In the embodiments of the present application, it needs to be further explained that this step is the core design of balancing positioning accuracy and device endurance, and the logic of each link is as follows: 1. Frequency differentiation adjustment of static / moving state The accuracy of UWB positioning is positively correlated with the ranging frequency (high-frequency ranging can improve the real-time performance of position updating), but high-frequency operation will significantly increase the power consumption of the tag (the built-in battery of the safety helmet has limited endurance). Therefore, the frequency needs to be dynamically switched according to the motion state of the personnel: Static state: When the personnel do not move actively, there is no need to frequently update the position, and reducing the ranging frequency (such as 0.5 Hz-2 Hz) can greatly reduce the power consumption and prolong the endurance time of the safety helmet; Moving state: When the personnel walk or work, the position change needs to be captured in real time to ensure the accuracy of clocking, and increasing the ranging frequency (such as 5 Hz-20 Hz) can ensure the positioning accuracy and avoid clocking failure due to delay.

[0053] 2. Step length setting Frequency mutation (such as jumping from 0.5 Hz directly to 20 Hz) may cause two major problems: Power consumption fluctuation: Instantaneous high-frequency operation will cause a sudden increase in battery current, shortening the battery life; Data stability: Sudden high-frequency ranging requests may cause signal conflicts between the base station and the tag, resulting in data loss or transmission delay.

[0054] Therefore, a step length (such as 0.5 Hz / time) is adopted for gradual adjustment, which makes the frequency transition smooth and ensures the stable operation of the system.

[0055] 3. Background remote configuration function Remote configuration allows administrators to modify the preset frequency in batches through the background server 23 without operating each safety helmet tag on site, greatly improving the adaptability and management efficiency of the system to different scenarios. Where the personnel are stationary for a long time, the static frequency can be set to a lower value (such as 0.5 Hz) to further save power; where the personnel move frequently, the moving frequency can be set to a higher value (such as 20 Hz) to ensure real-time positioning.

[0056] In summary, the design achieves the dual goals of "high-precision positioning" and "long-lasting use" through intelligent adaptation to motion states, smooth transition of frequencies, and flexible scenario configuration.

[0057] In the above step S3, when the UWB tag 221 interacts with at least three UWB positioning base stations 21 to measure distance data at the current frequency, it includes: The UWB tag 221 sends a distance measurement request signal containing its unique identification ID to each base station, and the base station returns a response signal containing its unique identification ID and a timestamp after receiving it; the timestamp is based on the time synchronization calibration result (such as an error of ≤1 ns), ensuring the time consistency of the distance measurement data; During the interaction of distance measurement data, the stability of the interaction link (such as signal strength, packet loss rate) is periodically detected; if the link stability is lower than the preset threshold, an automatic reconnection mechanism is triggered, and abnormal information is recorded to the background server 23, ensuring the continuity of the distance measurement data interaction; Among them, the current moving state identification (stationary / moving) is contained in the distance measurement request signal, and the base station processes the high-frequency distance measurement request in the moving state first after receiving it, improving the positioning response speed in the moving scenario.

[0058] In the embodiments of the present application, it needs to be further explained that step S3 is the core data interaction link connecting front-end sensing and back-end computing in the UWB high-precision positioning punch-in process, and its design closely revolves around the overall architecture, technical principles, and functional goals of the system. The specific principles are as follows: I. Data transmission bridge role in the overall architecture The overall architecture of the UWB positioning punch-in system consists of a multifunctional safety helmet 22 (front-end sensing layer), a UWB positioning base station 21 (data transmission layer), and a background server 23 (computing and storage layer). Step S3 is located at the junction of the data transmission layer and the front and back layers: Forward to the dynamic frequency adjustment of step S2 (determine the current distance measurement frequency according to the moving state); Provide raw input (distance measurement data) for position calculation in step S4; It is the key link for converting front-end tag state (moving / static) into back-end positioning results, and the absence of this link will result in no data available for processing in the subsequent Kalman filter preprocessing and triangulation algorithm, interrupting the punch-in process.

[0059] II. Precision guarantee at the level of technical principles The core technical principle of UWB positioning is time-of-flight (TOF) ranging: by calculating the propagation time of the UWB signal from the tag to the base station, and multiplying it by the speed of light, the distance between the two is obtained. This principle requires high accuracy in time synchronization. The design of step S3 directly serves the TOF accuracy: Timestamp synchronization calibration: the response signal returned by the base station contains a timestamp based on ≤1 ns error calibration, ensuring the consistency of signal transmission / reception timestamps between the tag and the base station, and eliminating the time error in TOF calculation; Interaction with at least three base stations: satisfies the geometric conditions of the three-edge measurement method, provides sufficient distance data for the subsequent step S4 triangular positioning algorithm, and avoids position ambiguity.

[0060] III. Implementation support for functional goals The core functional goal is to generate high-precision, low-power, and highly reliable punch records, and step S3 supports the achievement of the goal through the following design: 1. Link stability guarantee: periodically detect link indicators such as signal strength and packet loss rate, and automatically reconnect and record exceptions when the threshold is exceeded, ensuring continuous transmission of ranging data; 2. Real-time optimization in mobile scenarios: the ranging request signal contains a mobile state identifier, and the base station prioritizes processing high-frequency requests in mobile states, echoing step S2's dynamic frequency adjustment (high-frequency ranging in motion), to improve positioning response speed in mobile scenarios and avoid punch failure due to delays; 3. Data uniqueness identification: the request / response signals of the tag and the base station both contain unique IDs, ensuring that the background server 23 can accurately match the tag and the base station, and avoiding data confusion (such as ranging data conflicts from multiple tags or base stations).

[0061] In summary, step S3 is the data core of the UWB positioning punch process, its design not only follows the technical principles of TOF ranging and three-edge measurement, but also meets the functional goals of high precision, high reliability, and low power consumption. It is a key link connecting front-end sensing and back-end computing, providing necessary raw data support for subsequent position verification, wear detection, and punch record generation.

[0062] Referring to Figure 3 the punch effective area judgment flowchart, in the above step S4, when judging whether it is in the punch effective area, it includes: Ranging data preprocessing: through the background server 23, the original ranging data obtained by the UWB tag 221 interacting with each base station is smoothed one by one using the Kalman filter algorithm to eliminate random noise and sudden interference, and stable and reliable distance measurement values are output; Real-time position calculation: Based on the pre-registered position coordinates (x_i, y_i, z_i or x_i, y_i) of at least three UWB positioning base stations 21 and the filtered distance values d_i, the real-time three-dimensional coordinates (x, y, z) of the UWB tag 221 are solved by the trilateration method; if it is a two-dimensional positioning scene, the two-dimensional coordinates (x, y) are calculated; Valid area boundary verification: The background server 23 calls the pre-stored punch-in valid area boundary parameters (such as the polygon vertex coordinate set, the circular center coordinate and the radius), and substitutes the real-time position coordinates into the area judgment logic (such as whether the point is inside the polygon, whether the distance from the point to the center is less than the radius), to verify whether it is in the valid area; Position validity confirmation: If the real-time position is continuously determined to be in the valid area for M times (M≥1, such as 3 times), and the time interval between the adjacent two determinations is ≤ a preset threshold (such as 1 second), it is confirmed that the current position is valid; otherwise, it is determined to be invalid; Abnormal data processing: If the number of effective base stations participating in the calculation is less than three, the position calculation is suspended, the abnormal log is recorded, and the ranging data supplementing mechanism is triggered, and after obtaining the effective ranging data of at least three base stations, the position validity is reconfirmed.

[0063] It needs to be further explained in the embodiments of the application that step S4 is the core link for judging the validity of punch-in in the UWB high-precision positioning punch-in process, which is closely designed around the system "high-precision, high-reliability" punch-in target, combined with the UWB positioning technology principle and the actual scene demand, and the principles of each sub-step are as follows: I. Ranging data preprocessing: necessity of Kalman filtering The original ranging data of the UWB tag 221 and the base station is easy to be disturbed by the environment (such as multipath effect, signal shielding) to generate random noise or sudden deviation, which directly affects the position calculation accuracy. The Kalman filtering algorithm can effectively smooth the noise and correct the abnormal value through the dynamic recursive process of "prediction-update", and output stable and reliable distance measurement value - which is the premise of accurate subsequent position calculation, avoiding the misjudgment of punch-in position caused by original data error.

[0064] II. Real-time position calculation: technical basis of trilateration method UWB positioning relies on time of flight (TOF) ranging principle, which calculates the distance between the tag and the base station by signal propagation time. To solve the real-time position of the tag, at least three base stations with known coordinates (satisfy the geometric conditions of triangular positioning: non-collinear, cover the punch-in area) are needed, and the trilateration method (or triangulation method) is used to deduce the tag coordinates: Three-dimensional scene: based on the coordinates (x_i, y_i, z_i) of three base stations and the distance d_i, the tag (x, y, z) is obtained by solving the cubic quadratic equation set; Two-dimensional scene: simplified to plane coordinates (x, y) calculation.

[0065] This step is the key to convert "distance data" into "location information", which provides the basis for subsequent area verification.

[0066] Three, effective area boundary verification: the functional requirements of the punch-in scene Punch-in needs to be limited within the preset effective area (such as the entrance of the construction site, the office sign-in point of the construction site), to prevent "punch-in on behalf of others" or "punch-in outside the area". By pre-storing boundary parameters (such as polygon vertices, circle radius), the real-time location is substituted into the judgment logic (such as whether the point is inside the polygon, whether the distance to the center is less than the radius), to ensure that the punch-in behavior meets the scene rules.

[0067] Four, location validity confirmation: reliability design to avoid misjudgment Single location determination is easily affected by signal fluctuations (such as instantaneous obstruction) or temporary passing of personnel, leading to false punch-in. Therefore, a continuous verification mechanism needs to be introduced: Continuous M times (such as 3 times) determination in the effective area; The interval between adjacent determinations is ≤ a preset threshold (such as 1 second); The combination of the two ensures that the personnel are "real and continuous" in the punch-in area, improving the credibility of the punch-in result.

[0068] Five, abnormal data processing: guarantee of system robustness If the number of effective base stations participating in the calculation is less than 3 (such as base station failure, signal loss), the three-side measurement method cannot solve the unique location, and the positioning result is unreliable. At this time, the calculation is suspended, the exception is recorded, and the re-measurement mechanism is triggered, and after sufficient base station data is obtained, the verification is restarted - this is a key design to ensure the continuous and stable operation of the system in complex environments.

[0069] In summary, step S4 realizes the accurate judgment of the validity of the punch-in location through the complete link of "data purification → location solution → area verification → reliability confirmation → exception handling", laying a solid foundation for subsequent safety helmet wearing verification and punch-in record generation.

[0070] In the above step S5, when the microprocessor 224 verifies the correct wearing of the safety helmet based on the wearing detection sensor 222, it includes: Verify whether the infrared sensor continuously detects head blocking signals, and the fitting pressure value collected by the pressure sensor is ≥ a preset threshold; When the above two conditions are met and last for a preset duration (such as 2 seconds), it is determined as a correct wearing state; Wherein, if the correct wearing state is not detected, the microprocessor 224 prohibits sending a punch-in request to the background server 23, and the wearing detection sensor 222 includes an infrared sensor and a pressure sensor.

[0071] Further explained in the embodiments of the present application, the wearing detection of step S5 is a key compliance verification link connecting the position validity and the final clock-in record, and the core goal is to solve two major pain points: 1. Preventing clock-in cheating: avoiding the false behavior of "others holding safety helmets (only carrying without wearing) clocking-in in the effective area", ensuring that the clock-in subject and the wearer are consistent; 2. Ensuring safety regulation execution: for strong safety requirement scenarios such as construction and construction site, it is compulsory to verify whether the personnel truly and regularly wear safety helmets, in line with the safety production management regulations (such as the compulsory requirements for safety helmet wearing in the "Standard for Safety Inspection of Building Construction").

[0072] If the verification mechanism is missing, even if the personnel is in the clock-in effective area, there may be a violation of not wearing a safety helmet, resulting in the clock-in record losing the safety management value.

[0073] The wearing detection adopts a three-fold logic of "infrared obstruction detection + pressure adhesion detection + continuous duration verification" to ensure the accuracy of the judgment result: 1. Infrared sensor detects head obstruction: using the infrared sensor to detect the heat radiation or obstruction characteristics of the human head, to determine whether the safety helmet is placed on the head (rather than on the desktop, in the hand, etc. non-wearing scenarios), solving the problem of "whether the safety helmet is on the head"; 2. Pressure sensor detects adhesion pressure ≥ preset threshold: through the pressure sensor in the hat lining, the adhesion pressure of the head and the hat body is collected, to ensure that the safety helmet is not "loosely worn on the head", but is in a tight wearing state in line with the regulations (such as the construction scene requires the gap between the safety helmet and the head to be ≤5mm), solving the problem of "whether it is regularly worn"; 3. Double condition continuous for a preset duration (such as 2 seconds): avoiding false judgments caused by instantaneous obstruction (such as briefly obstructing the infrared by picking up the safety helmet) or accidental touch of the pressure sensor, to ensure that the wearing state is stable and real.

[0074] The microprocessor 224 completes the above-mentioned logical judgment locally in the safety helmet, without relying on the background server 23, which not only improves the response speed, but also reduces invalid data transmission.

[0075] This verification mechanism is deeply bound with the overall clock-in process and is an indispensable prerequisite: 1. Connection with step S4: only when step S4 determines that the personnel is in the clock-in effective area, the wearing detection of S5 is triggered (the position validity is the prerequisite for wearing verification, avoiding the invalid scenario of "wearing outside the area also clocking-in"); 2. Blocking of step S6: if the wearing verification fails, the microprocessor 224 directly prohibits the sending of a clock-in request to the background server 23, blocking the subsequent identity matching and record generation process, and ensuring the compliance of the clock-in record from the source; 3. Coordination with the hardware of the multifunctional safety helmet 22: relying on the infrared sensor, pressure sensor and microprocessor 224 integrated in the safety helmet, local real-time processing is realized, which conforms to the hierarchical architecture design of the system “front-end sensing + local decision + background calculation”.

[0076] In summary, the wearing detection mechanism of step S5 is an important support for the “high-precision positioning + real compliance clock-in” goal of the entire clock-in system, which not only guarantees the authenticity of the clock-in behavior, but also strengthens the landing execution of safety management.

[0077] In the above step S6, when the background server 23 matches the tag identification and the personnel identity, it includes: After the background server 23 receives the unique identification ID of the UWB tag 221, it accesses the pre-established tag-personnel association database; If there is a valid association record (not expired and not canceled) corresponding to the identification ID in the tag-personnel association database, the personnel identity information is extracted to complete the matching; if there is no association record or the association record is invalid, an identity verification exception is triggered, an alarm information is sent to the administrator, and an exception log (including identification ID, timestamp, exception type) is recorded; Among them, the tag-personnel association database stores the one-to-one correspondence between the unique identification ID of the UWB tag 221 and the personnel identity information (name, employee number, post).

[0078] In the embodiments of the present application, it needs to be further explained that the UWB tag 221 as a hardware device integrated in the safety helmet, its unique identification ID can only represent the physical device itself and cannot be directly associated with a specific person. To solve the problem of “who is using the hardware tag”, it is necessary to pre-establish a tag-personnel association database to one-to-one map the tag ID and the personnel identity information (name, employee number, post), which is a necessary prerequisite for converting “device clock-in behavior” into “personnel clock-in record”, ensuring that the subject of the clock-in record is clear and real.

[0079] In actual scenarios, there are dynamic situations such as personnel changes (such as resignation, job transfer), tag replacement (such as device damage), etc. If the association record is not updated in time, it may cause identity matching errors (such as the tag of a resigned personnel is still used for clock-in). Therefore, the association record needs to be set with the validity condition of “not expired and not canceled”, to ensure that the mapping relationship in the database is always consistent with the actual personnel-device binding state, avoiding the generation of invalid or false clock-in records.

[0080] When unknown tag check-in (unrelated records) or invalid tag check-in (records expired / revoked) occurs, trigger abnormal alarm and record logs, which is an important means of system security protection: Alarm mechanism: timely inform administrators to handle abnormal situations (such as strangers breaking in, ex-employees using irregularly); Log recording: store information such as identification ID, timestamp, and abnormal type to provide basis for subsequent problem troubleshooting and responsibility tracing, and strengthen the reliability and compliance of the system.

[0081] This step is the last identity verification checkpoint after position validity verification (step S4) and wearing specification verification (step S5). Only by passing the identity matching, can the "position data" and "wearing state" obtained in the previous steps be associated with the specific personnel, and a complete check-in record containing "who, where, and whether to wear" can be generated, realizing the full-link closed loop from hardware perception to personnel behavior record.

[0082] In summary, this step provides security protection at the identity level for the check-in system by establishing a trusted identity mapping relationship, dynamically maintaining association validity, and strengthening abnormal handling, ensuring that the generated check-in record has the legality and traceability of "one person with one certificate".

[0083] In the above step S6, when the real-time position and personnel state are associated to generate check-in records and stored, it includes: The following information is integrated into a standardized check-in record by the background server 23: Personnel identity information (from the identity matching result); Real-time positioning data (three-dimensional / two-dimensional coordinates after Kalman filtering); State data (moving / static state, correct safety helmet wearing state); Event metadata (check-in timestamp, list of base stations participating in ranging, current ranging frequency of UWB tag 221); And the standardized check-in record is stored in JSON format to ensure data readability and cross-system interoperability.

[0084] In the embodiments of the present application, it needs to be further explained that the personnel identity information: through the tag-personnel association database matching, the check-in subject is clear (solving the problem of "who checks in"); Real-time positioning data: coordinates after Kalman filtering, verifying the validity of the check-in location (solving the problem of "where to check in"); State data: moving / static state reflects the behavior mode at the time of check-in, and wearing state ensures compliance (solving the problem of "whether to check in regularly"); Event metadata: timestamp ensures timing accuracy, base station list and ranging frequency provide technical traceability for positioning results (solves the problem of whether the "clock-in record is reliable").

[0085] These data are scattered in the front-end perception layer (safety helmet sensor), transmission layer (base station), and computing layer (background server 23), and need to be integrated to form a complete closed loop to meet the needs of safety management, attendance statistics, and other business scenarios for "traceability and analysis".

[0086] In practical applications, the clock-in system needs to interface with HR systems, safety supervision platforms, and other external systems. If the data formats are not unified, it will lead to high cross-system interaction costs, data parsing errors, and other problems. Standardized clock-in records define fixed fields and data structures to ensure consistency, readability, and scalability.

[0087] The choice of JSON format storage is based on its advantages in cross-system interoperability and data lightweight: Lightweight and efficient: Compared with XML and other formats, JSON has low redundancy, small transmission and storage overhead, and adapts to the high-concurrency data processing needs of the background server 23; Cross-language support: Almost all major programming languages (Java, Python, JavaScript, etc.) natively support JSON parsing / generation, making it easy to seamlessly integrate clock-in records with HR, safety, and other systems; High readability: JSON content can be directly read, making it easy for administrators to troubleshoot clock-in abnormalities (such as confirming whether positioning relies on valid base stations through the base station list), and improving system operation efficiency.

[0088] In summary, this design integrates multi-dimensional data, standardized structure, and JSON storage to achieve the transformation of clock-in records from "technical data" to "business assets", providing a reliable foundation for subsequent data analysis, safety supervision, and cross-system collaboration.

[0089] Embodiment 2, see Figure 4 the clock-in system module interaction diagram, the present application provides a clock-in system based on multi-functional safety helmet UWB high-precision positioning as shown in Figure 4 , comprising: a background server 23, at least three UWB positioning base stations 21, and a multi-functional safety helmet 22; At least three UWB positioning base stations 21: deployed in the preset clock-in area, satisfying the triangular positioning geometric condition that any three base stations are not on the same straight line and cover the entire effective range of the preset clock-in area; establishing a bidirectional communication connection with the background server 23, and performing time synchronization calibration between each base station (calibration error ≤ preset threshold such as 1 ns level); for receiving ranging request signals from the multi-functional safety helmet 22, and returning response signals containing its own unique identifier ID and timestamp; Multifunctional safety helmet 22: integrated UWB tag 221, wearing detection sensor 222, acceleration sensor 223 and microprocessor 224; the microprocessor 224 is electrically connected with the UWB tag 221, the wearing detection sensor 222 and the acceleration sensor 223 respectively; wherein: UWB tag 221: sends a ranging request signal containing its unique identification ID to the UWB positioning base station 21; Acceleration sensor 223: collects three-axis acceleration data of personnel movement; Wearing detection sensor 222: detects whether the safety helmet is correctly worn; Microprocessor 224: detects personnel movement state based on acceleration sensor 223 data, dynamically adjusts UWB tag 221 ranging frequency (reduces to preset first frequency when stationary, increases to preset second frequency when moving), verifies whether the signal of wearing detection sensor 222 meets the correct wearing condition; Background server 23: receives ranging data uploaded by the UWB positioning base station 21, calculates the real-time position of the UWB tag 221 through the triangulation algorithm after Kalman filtering preprocessing; judges whether the real-time position is in the valid area of clock-in; if valid, receives the wearing verification result of the microprocessor 224, matches the unique identification ID of the UWB tag 221 with the personnel identity information, associates the real-time position, personnel state to generate standardized clock-in records and stores.

[0090] In a possible embodiment, the wearing detection sensor 222 includes an infrared sensor and a pressure sensor, the infrared sensor is used to detect head shielding signals, and the pressure sensor is used to collect the fitting pressure value.

[0091] Finally: the above only describes the preferred embodiments of the present application and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A punch card method based on multi-functional safety helmet UWB high-precision positioning, characterized in that, The method comprises the following steps: Deploy at least three UWB positioning base stations in the preset check-in area, and establish a communication connection between each base station and the background server; Detect the movement state of the personnel based on the acceleration sensor through the microprocessor, and dynamically adjust the ranging frequency of the UWB tag; When the personnel enter the check-in area, interact with at least three UWB positioning base stations at the current frequency to measure the ranging data, and send it to the background server; Preprocess the ranging data by Kalman filtering through the background server, and then calculate the real-time position by the triangulation algorithm to determine whether it is in the effective check-in area; If the position is valid, verify the correct wearing of the safety helmet based on the wearing detection sensor through the microprocessor; Match the tag identification with the personnel identity through the background server, associate the real-time position, personnel state to generate check-in records and store them.

2. The punch-in method according to claim 1, wherein, When deploying at least three UWB positioning base stations, it includes: Calibrate the time synchronization of all UWB positioning base stations, and control the calibration error within the preset threshold; Among them, the deployment positions of at least three UWB positioning base stations meet the geometric conditions of triangulation: any three base stations are not on the same straight line, and cover the entire effective range of the preset check-in area.

3. The punch-in method according to claim 1, wherein, When establishing a communication connection between each base station and the background server, it includes: Each UWB positioning base station uses wired or wireless communication protocol to establish a bidirectional data transmission link with the background server; Upload the unique identification ID, deployment position coordinates and hardware initial state parameters of each UWB positioning base station to the background server through each UWB positioning base station to complete identity registration; Verify the registration information of the base station through the background server, and if the verification is passed, feed back the connection success confirmation instruction to the base station, and store the base station information to the database; After establishing the communication connection, periodically detect the link stability, if the connection is interrupted, trigger the automatic reconnection mechanism, and record the abnormal log to the background server.

4. The punch-in method according to claim 1, wherein, When detecting the movement state of the personnel based on the acceleration sensor, it includes: Real-time collect three-axis acceleration data output by the acceleration sensor through the microprocessor at a preset sampling frequency; Low-pass filter the collected three-axis acceleration data; Calculate the modulus of the filtered three-axis acceleration data, and compare it with the preset static threshold and moving threshold; If the modulus is below the static threshold for a continuous preset number of times, it is determined to be a static state; if it is above the moving threshold for a continuous preset number of times, it is determined to be a moving state.

5. The punch-in method according to claim 4, wherein, When dynamically adjusting the ranging frequency of the UWB tag, it includes: When it is determined to be a static state, gradually reduce the ranging frequency of the UWB tag from the current value to the preset first frequency through the microprocessor; When it is determined to be a moving state, gradually increase the ranging frequency of the UWB tag from the current value to the preset second frequency through the microprocessor; Wherein, the step length of frequency adjustment is a preset value, and the preset first frequency and the preset second frequency can be remotely configured through the background server.

6. The punch-in method according to claim 2, wherein, When interacting with the ranging data at the current frequency, it includes: The UWB tag sends a ranging request signal containing its unique identification ID to each base station, and the base station returns a response signal containing its unique identification ID and a timestamp after receiving it; the timestamp is based on the time synchronization calibration result; In the interactive ranging data process, the stability of the interactive link is periodically detected; if the link stability is lower than a preset threshold, an automatic reconnection mechanism is triggered, and abnormal information is recorded to a background server; The ranging request signal contains a current mobile state identifier, and the base station processes the high-frequency ranging request in the mobile state preferentially after receiving the ranging request signal.

7. The punch-in method according to claim 1, wherein When determining whether to be in a valid clock-in area, the following steps are included: The original ranging data obtained by the UWB tag and each base station through the background server is smoothed one by one by using the Kalman filtering algorithm; Based on the pre-registered position coordinates of at least three UWB positioning base stations and the filtered distance values, the real-time three-dimensional coordinates of the UWB tag are solved by the trilateration method; if it is a two-dimensional positioning scene, the two-dimensional coordinates are calculated; The real-time position coordinates are substituted into the area judgment logic by calling the pre-stored clock-in valid area boundary parameters through the background server, to verify whether it is in the valid area; If the real-time position is continuously determined to be in the valid area for M times, and the time interval between the adjacent two determinations is less than or equal to a preset threshold, it is determined that the current position is valid; otherwise, it is determined to be invalid; If the number of effective base stations participating in the calculation is less than three, the position calculation is suspended, abnormal logs are recorded, and a ranging data supplementing mechanism is triggered, and after obtaining effective ranging data of at least three base stations, the position validity is reconfirmed.

8. The punch-in method of claim 1, wherein, When verifying the correct wearing of the safety helmet based on the wearing detection sensor, the following steps are included: Verify whether the infrared sensor continuously detects the head shielding signal, and whether the fitting pressure value collected by the pressure sensor is greater than or equal to a preset threshold; When the above two conditions are met and last for a preset time, it is determined that the safety helmet is correctly worn; If the correct wearing state is not detected, the microprocessor prohibits sending the clock-in request to the background server.

9. The punch-in method of claim 1, wherein, When matching the tag identifier and the personnel identity through the background server, the following steps are included: After receiving the unique identifier ID of the UWB tag through the background server, access the pre-established tag-personnel association database; If there is an effective association record corresponding to the identifier ID in the tag-personnel association database, extract the personnel identity information to complete the matching; if there is no such record or the association record is invalid, trigger identity verification exception, send alarm information to the administrator and record abnormal logs; The tag-personnel association database stores the one-to-one correspondence between the unique identifier ID of the UWB tag and the personnel identity information. When generating and storing the clock-in record by associating the real-time position and the personnel state, the following steps are included: Integrate the personnel identity information, real-time positioning data, state data and event metadata into a standardized clock-in record through the background server, and store the standardized clock-in record in JSON format.

10. A clock-in system based on multi-functional safety helmet UWB high-precision positioning, adopting the clock-in method of claim 1, characterized in that, It includes: At least three UWB positioning base stations: deployed in a preset clock-in area, and establishing a bidirectional communication connection with the background server; A multifunctional safety helmet: integrating a UWB tag, a wearing detection sensor, an acceleration sensor and a microprocessor; the microprocessor is electrically connected with each component; wherein: the microprocessor: based on the acceleration sensor data, detecting the personnel moving state, dynamically adjusting the ranging frequency of the UWB tag, and verifying whether the signal of the wearing detection sensor meets the correct wearing condition; Background server: receive the ranging data uploaded by the UWB positioning base station, preprocess the data by Kalman filter, calculate the real-time position of the UWB tag by triangulation positioning algorithm; judge whether the real-time position is in the valid area of clock-in; if valid, receive the wearing verification result of the microprocessor, match the unique identification ID of the UWB tag with the personnel identity information, associate the real-time position, personnel state to generate standardized clock-in record and store.

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