A method and system for wireless distributed data synchronization acquisition based on GPS timing

Abstract

This application provides a method and system for wireless distributed data synchronization acquisition based on GPS timing. Each acquisition unit receives GPS signals, acquires the GPS second pulse signal and its actual trigger time, calculates and calibrates the local clock drift rate to ensure that the local clock is consistent with the GPS clock; after calibrating a fixed delay, it acquires structural response data and generates an original timestamp, and obtains a calibrated timestamp by combining the fixed delay and drift rate correction. The central computer generates a globally unified timeline based on the calibrated timestamp, maps the data of each acquisition unit through linear interpolation, and outputs the synchronization result. This application requires no wiring, has high synchronization accuracy, and is suitable for structural health monitoring of large and complex projects such as super high-rise buildings.

Description

Technical Field

[0001] This application relates to the field of synchronous measurement technology, specifically a method and system for wireless distributed data synchronous acquisition based on GPS timing for super high-rise buildings. Background Technology

[0002] Existing distributed data acquisition methods still require interconnection via cabling to achieve data transmission and time synchronization between acquisition terminals. This prevents the distributed acquisition substructure from operating completely independently, and connecting all devices is extremely difficult for large-scale structural data acquisition. Furthermore, since the internal clock counters of each acquisition terminal are unlikely to be identical, time differences during acquisition can lead to asynchrony between the acquisition signals of different terminals. In summary, existing distributed synchronous data acquisition methods are insufficient to meet the high-precision synchronization requirements of large and complex engineering structures, severely restricting the synchronization, real-time performance, and reliability of engineering structure data acquisition, and failing to provide stable data support for critical operations such as structural health monitoring.

[0003] In super high-rise and large-scale building structures, the large spatial scale, numerous horizontal floor partitions, and dense steel structures lead to a shortage of vertical shaft resources, high costs for cross-floor cable laying, and inconvenience for subsequent maintenance, hindering the time synchronization data transmission of distributed acquisition nodes. High-precision data synchronization acquisition is crucial for achieving health and safety analysis in large and complex building projects. Existing distributed data synchronization acquisition technologies have achieved synchronous data acquisition to a certain extent, but their application is limited in two aspects. First, distributed acquisition terminals cannot be completely independent and still require interconnection through cabling to achieve data transmission and time synchronization, making them susceptible to external interference. Furthermore, connecting all devices is extremely difficult for large-scale structure data acquisition. Second, the time synchronization accuracy is insufficient. While network time protocol methods and algorithm software control methods are generally used to improve time synchronization accuracy, these methods still result in low synchronization accuracy and increased cabling complexity, hindering installation and integration.

[0004] The technical problem to be solved by this application is to provide a method and system for wireless distributed data synchronization acquisition based on GPS timing, so as to solve the above-mentioned technical problem. Summary of the Invention

[0005] The purpose of this application is to provide a method and system for wireless distributed data synchronization acquisition based on GPS timing, so as to solve the problems of existing distributed data acquisition relying on cabling, low synchronization accuracy, and inconvenient installation and maintenance.

[0006] The technical solution provided in this application is as follows:

[0007] In a first aspect, this application provides a method for wireless distributed data synchronization acquisition based on GPS timing, including:

[0008] GPS signal reception: Each acquisition unit receives GPS signals and obtains the GPS second pulse signal and its actual trigger time (the time of the GPS satellite clock at the trigger moment) from the GPS signals.

[0009] Local clock calibration: Each acquisition unit calculates the local clock drift rate based on the GPS second pulse signal, and calibrates the local clock according to the local clock drift rate to make the local clock and GPS clock originate from the same source;

[0010] Fixed delay calibration: Each acquisition unit calibrates a fixed delay between the actual trigger time of the GPS second pulse and the local timestamp of the acquired GPS second pulse record;

[0011] Data acquisition and timestamp calibration: Each acquisition unit acquires structural response data, generates an original timestamp for each data point in the structural response data based on the calibrated local clock, and corrects the original timestamp by combining the fixed delay and clock drift rate to obtain the calibrated timestamp;

[0012] Data interpolation alignment: The central computer generates a globally unified timeline based on the calibration timestamps of all acquisition units, and maps the structural response data acquired by each acquisition unit to the globally unified timeline through linear interpolation;

[0013] Synchronous data output: The central computer outputs synchronous structure response data mapped to a globally unified time axis.

[0014] In some possible implementations, the calculation process for the local clock drift rate includes:

[0015] Record the actual trigger time of two consecutively acquired GPS second pulses. and and the corresponding local clock count. and ;

[0016] According to the formula Calculate the local clock cycle ;

[0017] According to the formula Calculate the local clock drift rate ,in This refers to the standard clock cycle of the data acquisition terminal in the acquisition unit.

[0018] In some possible implementations, calibrating the local clock based on the local clock drift rate includes: adjusting the local clock frequency based on the local clock drift rate, using the formula: ,in To calibrate the local clock frequency, To calibrate the local clock frequency, This represents the local clock drift rate.

[0019] In some possible implementations, the calibration formula for the fixed delay is: ,in M To calibrate the number of times, For the first The actual trigger time of the second pulse collected in this instance. For the data acquisition terminal in the acquisition unit The local timestamp of the GPS second pulse record was collected for the first time.

[0020] In some possible implementations, the formula for calculating the calibration timestamp is: ,in For the first The original timestamps of each data point; For the first Calibration timestamps for each data point; This is the local timestamp of the last GPS second pulse record collected by the data acquisition terminal in the acquisition unit. Clock drift rate, For fixed delay.

[0021] In some possible implementations, the process of generating the globally unified timeline includes:

[0022] Determine the start time of the global unified timeline ,in This refers to the number of data acquisition units. For the first The calibration timestamp of the first data point of each acquisition unit;

[0023] Determine the end time of the globally unified timeline. ,in For the first The calibration timestamp of the last data point of each acquisition unit;

[0024] Determine the interval of the globally unified timeline ,in The sampling period for the data acquisition terminals in all acquisition units;

[0025] Generate a base timestamp sequence ,in , For indexing, The sequence length is... The maximum value, according to Scope defined: and .

[0026] In some possible implementations, the formula for calculating the linear interpolation is: ,in, For the global timeline The corresponding time of the first moment The structural response data (such as acceleration) values ​​of each acquisition unit, , For the first timeline of the global unified timeline At that moment, and For the first In each acquisition unit and Two adjacent calibration timestamps, and They are respectively and The corresponding structural response data;

[0027] Boundary padding is used for data that exceeds the time range of the acquisition unit.

[0028] Secondly, this application provides a system for wireless distributed data synchronization acquisition based on GPS timing, comprising: multiple acquisition units and a central computer;

[0029] The multiple acquisition units and the central computer are wirelessly connected, and the wireless distributed data synchronous acquisition with GPS timing is realized based on the above method.

[0030] In some possible implementations, the acquisition unit includes a sensor, a data acquisition terminal, an industrial control computer, a GPS timing module, and a wireless communication module;

[0031] The sensor is used to collect structural response data;

[0032] The data acquisition terminal is used to convert the structural response data from analog signals to digital signals, and to calibrate the local clock based on the GPS second pulse signal to generate a calibration timestamp for the digital signal.

[0033] The industrial control computer is used to store digital signals with calibration timestamps;

[0034] The GPS timing module is used to receive GPS satellite signals, obtain GPS second pulse signals and their actual trigger times, and transmit them to the data acquisition terminal.

[0035] The wireless communication module is used to transmit a digital signal with a calibration timestamp to the central computer;

[0036] The central computer is used to receive digital signals transmitted by each acquisition unit, generate a globally unified timeline, achieve data synchronization through interpolation alignment, and output synchronized data.

[0037] The specific implementation of the second aspect of this application can refer to the implementation of the first aspect, and will not be elaborated here.

[0038] Beneficial effects:

[0039] The method and system for wireless distributed data synchronization acquisition based on GPS timing provided in this application have the following beneficial effects:

[0040] Significantly improved clock synchronization accuracy: By combining GPS time synchronization with second pulse hard synchronization phase-locked loop and timestamp calibration algorithm, a synchronization accuracy of <1μs is achieved, which solves the problems of time base drift and insufficient synchronization accuracy in existing technologies, and ensures the time consistency of multi-node collaborative measurement and event positioning.

[0041] Balancing real-time performance and data integrity: The calibration timestamp is calculated in real time during the data acquisition process, eliminating the need for offline processing. Data integrity is ensured through interpolation and boundary filling strategies, making it suitable for structural health monitoring of large and complex projects such as super high-rise buildings, providing timely and accurate data support for structural health monitoring.

[0042] Highly integrated structure: The acquisition, processing and communication functions are integrated into the same hardware platform, reducing interface links and solving the problems of strong coupling of multiple boards, complex wiring and many failure points in the existing technology, which significantly improves the reliability of the device and the efficiency of installation and maintenance.

[0043] Highly efficient and reliable data transmission: It adopts 4G and other wireless communication modules to build a cross-regional, wire-free remote data transmission link, which gets rid of geographical environment limitations and avoids the effects of cable aging, electromagnetic interference and other factors. It is suitable for scenarios where monitoring points of large engineering structures are scattered and wiring is difficult. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the method flow in one embodiment of this application;

[0045] Figure 2 This is a schematic diagram of the system structure in one embodiment of this application. Detailed Implementation

[0046] To enable those skilled in the art to better understand the present application, the technical solution of the present application will be further described in detail below with reference to the embodiments and accompanying drawings.

[0047] Example 1:

[0048] This application provides a method for wireless distributed data synchronization acquisition based on GPS timing. This method achieves high-precision time synchronization among multiple acquisition units through GPS timing, and combines this with data processing algorithms to realize synchronous acquisition of wireless distributed data.

[0049] GPS time synchronization is a high-precision time synchronization method. The signal that GPS sends to the ground contains the precise time of the GPS satellites themselves. (Maintained by satellite atomic clocks) and GPS satellite position coordinates The time when the local receiving terminal (such as the acquisition terminal) receives the signal is the time recorded by the local clock. (If there is an error), then the signal propagation time It can be represented as:

[0050] (1);

[0051] In formula (1), The speed of light (approximately) m / s), The initial deviation between the local clock and the GPS satellite clock represents the spatial distance of the signal from the GPS satellite to the local receiving terminal. GPS satellite coordinates Coordinates of the local receiving terminal calculate:

[0052] (2);

[0053] Theoretical value of signal propagation time in vacuum for:

[0054] (3);

[0055] In actual propagation, corrections are needed for ionospheric and tropospheric delays (collectively referred to as...). (The correction parameters are provided by the navigation message in the GPS signal), therefore the corrected propagation time is:

[0056] (4);

[0057] After receiving the signal, the local receiving terminal compares it. and Calculate the local clock offset :

[0058] (5);

[0059] like This indicates that the local clock has an error and needs to be adjusted. To Coordinated Universal Time )time (Satellite time) Synced to ):

[0060] (6);

[0061] To improve accuracy, signals from four or more satellites are typically received, and the optimal clock offset is fitted using the least squares method. Let the... The time of the satellite is The time when the local receiving terminal receives the corresponding signal is Then the error equation is (assuming there is) One satellite, ):

[0062] (7);

[0063] In formula (7), To measure noise ( Transform formula (7) into an error equation, highlighting the parameters to be determined. :

[0064] (8);

[0065] make Then formula (8) can be simplified to:

[0066] (9);

[0067] Find the optimal solution by minimizing the sum of squared errors. To minimize the sum of squared noise from all satellites, then:

[0068] (10);

[0069] This refers to the number of satellites.

[0070] Find the equation (10) with respect to... The derivative of , and set it to 0 (extremum condition):

[0071] (11);

[0072] Formula (11) can be simplified to get:

[0073] (12);

[0074] Formula (12) can be transformed into:

[0075] (13);

[0076] but The optimal solution can be obtained as follows:

[0077] (14);

[0078] The core of GPS time synchronization is to correct for signal propagation delay and calculate the local clock and GPS satellite time synchronization. The time deviation is ultimately resolved through the formula. Time synchronization can be achieved, and errors can be further reduced through the fusion of multi-satellite data.

[0079] This application provides a method for wireless distributed data synchronization acquisition based on GPS timing. To further improve time synchronization, multiple data acquisition terminals (acquisition cards) are synchronized by employing GPS second pulse hard synchronization phase-locked loop and timestamp calibration algorithms. Using the GPS second pulse as a reference, the frequency and phase of the local clock (CLK) of each data acquisition terminal are calibrated to ensure that the clocks of each data acquisition terminal are from the same source as the GPS clock.

[0080] The implementation of this application will be described in detail below with reference to the accompanying drawings.

[0081] like Figure 1 As shown, this application provides a method for wireless distributed data synchronization acquisition based on GPS timing, including:

[0082] S1. GPS signal reception: Each acquisition unit receives GPS signals and obtains the GPS second pulse signal and its actual trigger time (the time of the GPS satellite clock at the trigger moment) from the GPS signals.

[0083] It should be understood that before receiving GPS signals, each acquisition unit can first perform program initialization processing to configure the acquisition channels of the data acquisition terminal accordingly (such as sampling frequency, range, number of channels, etc.).

[0084] S2. Local clock calibration: Each acquisition unit calculates the local clock drift rate based on the GPS second pulse signal, and calibrates the local clock according to the local clock drift rate to make the local clock and GPS clock originate from the same source.

[0085] It should be understood that in this step, for each GPS second pulse received by the data acquisition terminal, the local clock is triggered to count, and the deviation from the standard clock period (e.g., 1 second) is calculated. The local clock drift rate is then calculated. The clock frequency is adjusted in real time to ensure that the local clock does not "go off track".

[0086] In some embodiments, the GPS second pulse time between two consecutive pulses is set to... and (At 1-second intervals), the local clock counts as follows: and The local clock period is:

[0087] (15);

[0088] The local clock drift rate is:

[0089] (16);

[0090] , This is the standard clock frequency for the data acquisition terminal.

[0091] The data acquisition terminal uses a built-in clock calibration module to determine the local clock drift rate. Adjust the local clock frequency and correct the formula:

[0092] (17);

[0093] The local clock frequency before calibration, and after calibration... .

[0094] S3. Fixed delay calibration: Each acquisition unit calibrates the fixed delay between the actual trigger time of the GPS second pulse and the local timestamp of the GPS second pulse record acquired by the data acquisition terminal.

[0095] When the data acquisition terminal receives the GPS second pulse, a slight delay occurs between the actual trigger time of the GPS second pulse and the data acquisition time, which needs to be corrected using a timestamp algorithm. In some embodiments, the actual trigger time of the GPS second pulse (GPS time) and the corresponding local timestamp are collected multiple times, and the average value is taken as a fixed delay:

[0096] (18);

[0097] In equation (18), The delay is a fixed delay (the hardware delay from GPS second pulse input to timestamp generation, which needs to be pre-calibrated). M For the calibration number; For the first The actual trigger time of the GPS second pulse collected in each iteration; For the data acquisition terminal The local timestamp of the GPS second pulse record was collected for the first time.

[0098] In some embodiments, an initial fixed delay calibration can be performed after system startup, followed by recalibration every hour. Fixed delay calibration can address delay shifts caused by temperature variations.

[0099] S4. Data Acquisition and Timestamp Calibration: Each acquisition unit acquires structural response data, generates an original timestamp for each data point in the structural response data based on the calibrated local clock, and corrects the original timestamp by combining the fixed delay and clock drift rate to obtain the calibrated timestamp.

[0100] In some embodiments, the data acquisition terminal stamps the original timestamp for each data point according to the local calibrated clock. The calibration timestamp is:

[0101] (19);

[0102] In equation (19), For the first The original timestamps of each data point; For the first Calibration timestamps for each data point; This is the local timestamp of the last time the data acquisition terminal collected a GPS second pulse record. Used to correct clock drift between two GPS second pulses.

[0103] In some embodiments, the calibration timestamp for each data point can be calculated in real time during the acquisition process, eliminating the need for subsequent offline processing and improving efficiency.

[0104] S5. Data Interpolation Alignment: The central computer generates a globally unified time axis based on the calibration timestamps of all acquisition units, and maps the structural response data acquired by each acquisition unit to the globally unified time axis through linear interpolation.

[0105] If there are slight differences in the timestamps of different data acquisition terminals (e.g., less than the synchronization accuracy threshold) , (Values ​​can be less than 10ns). An "interpolation point supplementation" strategy is used to generate aligned data through linear interpolation to ensure data integrity.

[0106] Multiple data acquisition terminals will calibrate the timestamps. The collected data is stored together with the data, and the host computer aligns and merges the data from all data acquisition terminals according to the timestamp.

[0107] Let the data acquisition terminal A be the first Each data timestamp is The j-th data timestamp of data acquisition terminal B is When the following conditions are met:

[0108] (20);

[0109] Then determine and Alignment is achieved for data collected at the same time.

[0110] Assuming there are N data acquisition terminals in a distributed system, the th... The calibrated data from each data acquisition terminal is as follows:

[0111] Calibration timestamp sequence:

[0112] (twenty one);

[0113] Acceleration signal sequence:

[0114] (twenty two);

[0115] A globally unified timeline is generated based on the calibration timestamps of all data acquisition terminals. , The time range covering all data acquisition terminals is:

[0116] (twenty three);

[0117] (twenty four);

[0118] Time axis interval:

[0119] (25);

[0120] To obtain the minimum sampling period for all data acquisition terminals, ensuring no details are lost.

[0121] Baseline timestamp sequence:

[0122] (26);

[0123] in .

[0124] Different data acquisition terminals (such as) and Any two calibration timestamps (e.g.) and The absolute difference must be less than the synchronization accuracy threshold. ,at the same time No more than the global timeline interval This ensures that the data streams corresponding to these two timestamps are adjacent or within the same time granularity on the global timeline, satisfying the mathematical conditions for linear interpolation, namely:

[0125] (27);

[0126] in, For the first The first data acquisition terminal The calibration timestamp of each data point For the first The first data acquisition terminal The calibration timestamps for each data point.

[0127] For each data acquisition terminal , and its data Mapped to the global timeline Generate an alignment sequence .

[0128] For each target moment on the global timeline In the data acquisition terminal Find two adjacent points in the calibration timestamp and ,satisfy:

[0129] (28);

[0130] in For range index ( ).

[0131] Define normalized time difference (reflect (relative position within the interval)

[0132] (29);

[0133] The range of values ​​for is: ;

[0134] Normalized time difference As weights, weighted calculation Structural response data (e.g., acceleration) at any given moment :

[0135] (30);

[0136] The physical meaning of Equation (30) is to estimate the signal value at the target time by linear weighting of two adjacent points, and the error is proportional to the rate of change of the signal.

[0137] when Beyond the data acquisition terminal Time range (when) When a data calibration timestamp is earlier than the first data calibration timestamp of the data acquisition terminal or later than the last data calibration timestamp (indicating it to be outside the time range), boundary padding is used.

[0138] 1. If (Target time is earlier than the data collection start time): This means forward padding, preserving the first data element;

[0139] 2. If (Target time is later than the end point of data collection): This refers to backfilling, where the last data point is retained; This indicates the last data index.

[0140] S6. Synchronous Data Output: The central computer outputs synchronous structure response data mapped to a globally unified time axis.

[0141] Example 2:

[0142] This application provides a system for wireless distributed data synchronization acquisition based on GPS timing, including: multiple acquisition units and a central computer;

[0143] The multiple acquisition units and the central computer are wirelessly connected, and wireless distributed data synchronous acquisition with GPS timing is realized based on the method described in Embodiment 1.

[0144] In some embodiments, the acquisition unit includes a sensor, a data acquisition terminal, an industrial control computer, a GPS timing module, and a wireless communication module;

[0145] The sensor is used to collect structural response data;

[0146] The data acquisition terminal is used to convert the structural response data from analog signals to digital signals, and to calibrate the local clock based on the GPS second pulse signal to generate a calibration timestamp for the digital signal.

[0147] The industrial control computer is used to store digital signals with calibration timestamps;

[0148] The GPS timing module is used to receive GPS satellite signals, obtain GPS second pulse signals and their actual trigger times, and transmit them to the data acquisition terminal.

[0149] The wireless communication module is used to transmit a digital signal with a calibration timestamp to the central computer;

[0150] The central computer is used to receive digital signals transmitted by each acquisition unit, generate a globally unified timeline, achieve data synchronization through interpolation alignment, and output synchronized data.

[0151] like Figure 2 The diagram shown is a schematic of the hardware components of a system, in the structure to be detected. Each measuring point is set up. An independent acquisition unit is used. Sensors collect the dynamic response of the structure, and the analog signals of the structural response are converted into digital signals and stored in the industrial control computer via a data acquisition terminal. Simultaneously, the digitized structural response signals are transmitted to the central computer via a 4G module. When acquiring response signals from different measurement points, each acquisition unit needs to simultaneously record the second pulse information of the GPS satellite system to assign unified time information to the response signals from different measurement points. Then, based on the second pulse, the time and phase synchronization of the response signals from different measurement points is achieved.

[0152] The system hardware, serving as the system's front end, can be distributed across different locations to collect data from various sensors, with each acquisition node possessing independent acquisition capabilities. This integrated distributed synchronous data acquisition hardware highly integrates multiple functional modules onto a single hardware platform, significantly improving overall system performance and operational reliability while effectively reducing signal attenuation and external interference risks, providing strong assurance for the stability and accuracy of data acquisition. Furthermore, the system can flexibly deploy acquisition nodes according to the building's structural scale and actual monitoring needs, achieving comprehensive, blind-spot-free health monitoring of the building structure.

[0153] For example, the system hardware may include the following interfaces: (1) GNSS signal input interface for connecting a GNSS antenna; (2) WIFI interface for connecting a router's WIFI interface to achieve wireless communication; (3) 4G interface for connecting a router's 4G interface to ensure data transmission in outdoor and offline environments; (4) PWR indicator light for indicating whether the hardware architecture power is on in real time; (5) signal input channels. For example, the NI-9202 data acquisition terminal includes 16 signal input channels, of which CH0~CH14 are valid acquisition channels, and CH15 is connected to the PPS signal by default and is not used as an acquisition channel; (6) HDMI interface for establishing a connection with the industrial computer's HDMI interface; (7) USB interface for connecting to the industrial computer's USB interface; (8) LAN interface for connecting to the industrial computer's Ethernet port to achieve stable wired communication.

[0154] In some embodiments, a distributed data synchronization acquisition and monitoring system can be built using LabVIEW programming software. Leveraging LabVIEW's advantages in data processing and system integration, this system, through a distributed architecture design, can efficiently and synchronously acquire data from multiple nodes and of multiple types, and can perform real-time data monitoring and management, effectively ensuring the timeliness and consistency of data acquisition.

[0155] This application proposes and successfully implements an integrated distributed synchronous data acquisition system hardware design. This hardware architecture efficiently integrates the multiple modules required for distributed data acquisition through a unified integrated architecture. This not only simplifies the structural design of terminal devices but also enables precise time synchronization and collaborative work among acquisition nodes in distributed deployment scenarios, effectively improving the overall efficiency and reliability of data acquisition.

[0156] This application has the following advantages:

[0157] (1) Highly integrated structure: Existing technologies adopt a multi-board strongly coupled structure, which is complex in wiring and has many fault points. This solution integrates the acquisition, processing and communication required for distributed data acquisition into a single hardware platform, which simplifies the structural design of terminal equipment, reduces interface links, effectively improves the overall efficiency and reliability of data acquisition, and significantly improves the reliability of the device and the efficiency of installation and maintenance.

[0158] (2) Significantly improved clock synchronization accuracy: Existing technology solutions from different manufacturers are inconsistent, resulting in time base drift of less than one second. This solution uniformly adopts BeiDou / GPS synchronization and PPS / UTC allocation to achieve high-precision (less than 1µs synchronization accuracy) wide-area clock synchronization among multiple terminals, maintains stability in long-term operation, and ensures the time consistency of multi-node collaborative measurement and event positioning.

[0159] (3) High-efficiency and reliable data transmission: Existing technologies achieve data transmission through cabling interconnection, which is not only greatly limited by geographical environment, but also susceptible to signal interference from cable aging and electromagnetic interference. This solution adopts wireless data interconnection, such as 4G wireless communication modules combined with multiple protection mechanisms to build a cross-regional, cabling-free remote data transmission link, achieving high-efficiency and reliable data transmission.

[0160] (4) Real-time monitoring and intelligent early warning: Existing technologies mostly rely on manual inspections or single-dimensional data monitoring, resulting in problems such as monitoring lag, slow early warning response, and incomplete structural status assessment. This solution allows each data acquisition terminal to interconnect with a cloud-based monitoring platform via wireless communication modules such as 4G. The cloud-based monitoring platform enables multi-dimensional real-time visual monitoring, allowing monitoring personnel to intuitively grasp the overall health status of the structure and changes in key local data. It is suitable for application scenarios where monitoring points are scattered and on-site wiring is difficult in large-scale engineering structural health monitoring.

[0161] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for wireless distributed data synchronization acquisition based on GPS timing, characterized in that, include: GPS signal reception: Each acquisition unit receives GPS signals and obtains the GPS second pulse signal and its actual trigger time from the GPS signals; Local clock calibration: Each acquisition unit calculates the local clock drift rate based on the GPS second pulse signal. Specifically, it records the actual trigger time of two consecutively acquired GPS second pulses. and and the corresponding local clock count. and According to the formula Calculate the local clock cycle According to the formula Calculate the local clock drift rate ,in This refers to the standard clock cycle of the data acquisition terminal in the acquisition unit; The local clock is calibrated according to the local clock drift rate to ensure it is consistent with the GPS clock. Specifically, this includes adjusting the local clock frequency based on the local clock drift rate, using the following formula: ,in To calibrate the local clock frequency, For the calibrated local clock frequency; Fixed Delay Calibration: Each acquisition unit calibrates a fixed delay between the actual trigger time of the GPS second pulse and the local timestamp of the acquired GPS second pulse record. The calibration formula is as follows: ,in For a fixed delay, M To calibrate the number of times, For the first The actual trigger time of the second pulse collected in this instance. For the data acquisition terminal in the acquisition unit The local timestamp of the GPS second pulse record was collected for the first time; Data Acquisition and Timestamp Calibration: Each acquisition unit acquires structural response data, generates an original timestamp for each data point in the structural response data based on the calibrated local clock, and corrects the original timestamp by combining the fixed delay and clock drift rate to obtain the calibrated timestamp. The calculation formula is as follows: ,in For the first The original timestamps of each data point; For the first Calibration timestamps for each data point; This is the local timestamp of the last GPS second pulse record collected by the data acquisition terminal in the acquisition unit; Data interpolation alignment: The central computer generates a globally unified timeline based on the calibration timestamps of all acquisition units, and maps the structural response data acquired by each acquisition unit to the globally unified timeline through linear interpolation; Synchronous data output: The central computer outputs synchronous structure response data mapped to a globally unified time axis.

2. The method according to claim 1, characterized in that, The process of generating the globally unified timeline includes: Determine the start time of the global unified timeline ,in This refers to the number of data acquisition units. For the first The calibration timestamp of the first data point of each acquisition unit; Determine the end time of the globally unified timeline. ,in For the first The calibration timestamp of the last data point of each acquisition unit; Determine the interval of the globally unified timeline ,in The sampling period for the data acquisition terminals in all acquisition units; Generate a base timestamp sequence ,in , For indexing, The sequence length is... The maximum value, according to Scope defined: and .

3. The method according to claim 1, characterized in that, The formula for calculating the linear interpolation is: ,in, For the global timeline The corresponding time of the first moment The structural response data values ​​of each acquisition unit , For the first timeline of the global unified timeline At that moment, and For the first In each acquisition unit and Two adjacent calibration timestamps, and They are respectively and The corresponding structural response data; Boundary padding is used for data that exceeds the time range of the acquisition unit.

4. A system for wireless distributed data synchronization and acquisition based on GPS timing, characterized in that, include: Multiple acquisition units and a central computer; The multiple acquisition units and the central computer are wirelessly connected, and GPS-synchronized wireless distributed data acquisition is achieved based on the method described in any one of claims 1 to 3.

5. The system according to claim 4, characterized in that, The acquisition unit includes a sensor, a data acquisition terminal, an industrial control computer, a GPS timing module, and a wireless communication module; The sensor is used to collect structural response data; The data acquisition terminal is used to convert the structural response data from analog signals to digital signals, and to calibrate the local clock based on the GPS second pulse signal to generate a calibration timestamp for the digital signal. The industrial control computer is used to store digital signals with calibration timestamps; The GPS timing module is used to receive GPS satellite signals, obtain GPS second pulse signals and their actual trigger times, and transmit them to the data acquisition terminal. The wireless communication module is used to transmit a digital signal with a calibration timestamp to the central computer; The central computer is used to receive digital signals transmitted by each acquisition unit, generate a globally unified timeline, achieve data synchronization through interpolation alignment, and output synchronized data.

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