Sampling point compensation method and device based on second pulse frequency offset, medium and product

Abstract

The application discloses a kind of based on sampling point compensation method, device, medium and product of second pulse frequency deviation, it is related to sampling point error compensation technical field.The present application includes reading the count value of local timer when current second pulse signal arrives;The measured frequency of high-speed external clock of local high-stability crystal oscillator in current second pulse signal period is calculated;Measured frequency and the theoretical frequency of local high-stability crystal oscillator, or actual sampling point number and theoretical sampling point number, determine the frequency deviation error rate of current second pulse signal period;Effective discrimination is carried out to the frequency deviation error rate of current second pulse signal period, and the effective frequency deviation error rate of discrimination is carried out multi-period smooth filtering processing, and the filtering frequency deviation error rate is obtained;The difference between theoretical sampling point number and actual sampling point number is calculated, and the discrete compensation point number is obtained;Period boundary discrete compensation is carried out based on discrete compensation point number, and the filtering frequency deviation error rate is mechanically sampled point number single point compensation.The present application can realize the sampling point error compensation of nodal seismic acquisition instrument.

Description

Technical Field

[0001] This invention belongs to the field of sampling point error compensation technology, specifically relating to a sampling point compensation method, device, medium, and product based on second pulse frequency offset. Background Technology

[0002] Nodal seismic acquisition systems are suitable for high-density, cableless, distributed seismic exploration. Each node typically performs sensing, sampling, timing, storage, and status recording independently, and the data is collected and processed uniformly after large-scale deployment. Because each node operates independently in the field and lacks a real-time wired synchronization link between nodes, the local sampling time accuracy of each node directly affects the alignment of data from multiple nodes.

[0003] In seismic exploration, sampling time errors can cause phase arrival time deviations, waveform phase shifts, cross-correlation peak shifts, and a decrease in superposition energy. For applications such as shallow high-resolution exploration, weak reflection identification, and imaging of complex geological bodies, temporal consistency among multiple nodes is particularly important.

[0004] Existing nodal seismic acquisition instruments typically use a Global Navigation Satellite System (GNSS) module to obtain absolute time and use the second pulse signal output by the GNSS to synchronize the system clock. However, GNSS signals may be unstable in environments such as mountainous areas, dense forests, mining areas, valleys, and urban areas with obstructed signals, and continuously keeping the GNSS module running will also increase power consumption. To ensure long-term operation, nodal devices usually need to rely on a local temperature-compensated crystal oscillator (TCXO), a voltage-controlled temperature-compensated crystal oscillator (VCTCXO), or other high-stability crystal oscillators for continuous timekeeping and sampling.

[0005] While local crystal oscillators can provide a continuous clock signal, their output frequency is affected by power supply conditions, component differences, long-term operating conditions, and external connections. When a node samples continuously for hours, days, or even tens of days, small frequency deviations can accumulate into significant sampling point errors. These errors not only manifest as system time skew but also cause discrepancies between the actual and theoretical number of sampling points for the analog-to-digital converter (ADC) within a timing cycle. If this issue is not addressed, subsequent data timeline alignment, data slicing, and multi-node collaborative processing may all be affected.

[0006] Existing methods mostly focus on GNSS calibration of the real-time clock (RTC) or system time, or rely on crystal oscillator temperature compensation. However, they lack closed-loop compensation mechanisms for errors caused by local sampling clock frequency offset in the continuous sampling data stream of the ADC, such as over-sampling, under-sampling, and cumulative sampling errors. Therefore, it is necessary to propose a sampling point error compensation scheme that is more suitable for the embedded workflow of nodal seismic acquisition instruments. Summary of the Invention

[0007] The purpose of this invention is to provide a sampling point compensation method, device, medium, and product based on second pulse frequency offset, in order to solve the above-mentioned problems existing in the prior art.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a sampling point compensation method based on second pulse frequency offset, applied to a nodal seismic acquisition instrument, comprising: In high-speed external bypass mode, read the count value of the local timer when the current second pulse signal arrives; The measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period is calculated based on the difference between the count value of the local timer between the current second pulse signal and the previous second pulse signal. Based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period, or the actual number of sampling points of the analog-to-digital converter within the current second pulse signal period and the theoretical number of sampling points, the frequency offset error rate of the current second pulse signal period is determined. The actual number of sampling points within the second pulse signal period refers to the total number of valid data points in the buffer of the analog-to-digital converter within the second pulse signal period. The frequency offset error rate of the current second pulse signal period is effectively determined, and the determined effective frequency offset error rate is subjected to multi-cycle smoothing filtering to obtain the filtered frequency offset error rate. The number of discrete compensation points is obtained by calculating the difference between the theoretical number of sampling points and the actual number of sampling points of the analog-to-digital converter in the current second pulse signal period; Based on the number of discrete compensation points, the number of sampling points is periodically boundary discretely compensated in the next second pulse signal period. According to the filter frequency offset error rate, the cumulative error variable is accumulated point by point in the next second pulse signal period, and when the absolute value of the cumulative error variable is greater than or equal to 1, the single-point compensation of the number of sampling points is triggered.

[0009] In one possible design, the method further includes, before reading the count value of the local timer when the current second pulse signal arrives: After the nodal seismic acquisition instrument is powered on or woken up from a low-power state, the GNSS module is started and GNSS timing initialization is performed; Switch the system clock of the nodal seismic acquisition instrument to high-speed external bypass mode.

[0010] In one possible design, after reading the count value of the local timer when the current second pulse signal arrives, the method further includes: Determine whether the local timer counter will overflow between the current second pulse signal and the previous second pulse signal; If the local timer counter does not overflow between the current second pulse signal and the previous second pulse signal, the difference between the count values ​​of the local timer between the current second pulse signal and the previous second pulse signal is determined according to the following formula; C_k = Count_k - Count_{k-1} If the local timer counter overflows between the current second pulse signal and the previous second pulse signal, the difference between the local timer count value between the current second pulse signal and the previous second pulse signal is determined according to the following formula; C_k=Count_k+Count_max-Count_{k-1} Where Count_k represents the count value of the local timer when the current second pulse signal arrives, Count_{k-1} represents the count value of the local timer when the previous second pulse signal arrives, and Count_max represents the maximum count value of the local timer. Based on the difference between the count value of the local timer between the current second pulse signal and the previous second pulse signal, the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period is calculated according to the following formula. HSE_Actual_Fq,k=C_k / T_pps Where T_pps represents the duration corresponding to the current second pulse signal period.

[0011] In one possible design, the frequency offset error rate of the current second pulse signal period is determined based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period, or the actual number of sampling points of the analog-to-digital converter and the theoretical number of sampling points within the current second pulse signal period. This includes: If the main control system of the nodal seismic acquisition instrument is currently in the taming phase, the frequency offset error rate of the current second pulse signal period is determined according to the following formula based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period. TimeErrorRate_k=(HSE_Actual_Fq,k-HSE_THEORY_FQ) / HSE_Actual_Fq,k Where HSE_Actual_Fq,k represents the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period, and HSE_THEORY_FQ represents the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period; If the main control system of the nodal seismic acquisition instrument is currently in the stable phase after the taming phase, the frequency offset error rate of the current second pulse signal period is determined according to the following formula based on the actual number of sampling points and the theoretical number of sampling points of the analog-to-digital converter in the current second pulse signal period; TimeErrorRate_k=(N_a,k-N_t,k) / N_a,k Where N_a,k represents the actual number of sampling points of the analog-to-digital converter within the current second pulse signal period, and N_t,k represents the theoretical number of sampling points of the analog-to-digital converter within the current second pulse signal period.

[0012] In one possible design, the frequency offset error rate of the current second-pulse signal period is effectively determined, and the determined effective frequency offset error rate is subjected to multi-cycle smoothing filtering to obtain the filtered frequency offset error rate, including: Determine whether the absolute value of the frequency offset error rate of the current second-pulse signal period exceeds a first preset error rate threshold. If it does not exceed the first preset error rate threshold, then the frequency offset error rate of the current second-pulse signal period is determined to be valid; or Determine whether the absolute value of the frequency offset error rate difference between the current second-count signal cycle and the previous second-count signal cycle exceeds a second preset error rate threshold. If it does not exceed the second preset error rate threshold, then the frequency offset error rate of the current second-count signal cycle is determined to be valid. The frequency offset error rate difference of the previous second-count signal cycle is the difference between the frequency offset error rate of the previous second-count signal cycle and the frequency offset error rate of the adjacent second-count signal cycle before the previous second-count signal cycle. If the frequency offset error rate of several consecutive second pulse signal cycles is invalid, then mark the clock state of the analog-to-digital converter as abnormal. If the frequency offset error rate of at least one of the most recent consecutive second-shot signal cycles is valid, then the average value of the frequency offset error rates of the most recent consecutive valid second-shot signal cycles is calculated to obtain the filtered frequency offset error rate; wherein, the valid second-shot signal cycle is the second-shot signal cycle in which the frequency offset error rate is valid.

[0013] In one possible design, based on the number of discrete compensation points, period boundary discrete compensation is performed on the number of sampling points in the next second pulse signal period, including: Based on the discrete compensation points, a one-time sampling point compensation is performed at the beginning of the next second pulse signal cycle; Based on the filter frequency offset error rate, the cumulative error variable is accumulated point by point within the next second pulse signal period, and single-point compensation of the sampling point number is triggered when the absolute value of the cumulative error variable is greater than or equal to 1, including: The cumulative error variable is accumulated point by point within the next second pulse signal period based on the filter frequency offset error rate; When the absolute value of the cumulative error variable is greater than or equal to 1 and the cumulative error variable is positive, then the number of sampling points is increased by one and the increased number of sampling points is written to the buffer. When the absolute value of the cumulative error variable is greater than or equal to 1 and the cumulative error variable is negative, the control buffer write pointer is pushed back by one sampling point.

[0014] In one possible design, before performing periodic boundary discrete compensation and triggering single-point compensation of the number of sampling points, the method further includes: Determine whether the write pointer of the current buffer will go out of bounds, whether the current buffer has enough space, whether the number of discrete compensation points exceeds the preset compensation point threshold, whether a file write operation is currently being performed, whether the current analog-to-digital converter sampling task is in the allowed sampling point compensation state, whether the current GNSS module is abnormal, and whether the current second pulse signal is abnormal. The method, based on the number of discrete compensation points, performs periodic boundary discrete compensation on the number of sampling points in the next second pulse signal period. It accumulates the cumulative error variable point-by-point within the next second pulse signal period according to the filter frequency offset error rate, and triggers single-point compensation of the number of sampling points when the absolute value of the cumulative error variable is greater than or equal to 1. This includes: If the write pointer of the current buffer does not go out of bounds, the current buffer has enough space, the number of discrete compensation points does not exceed the preset compensation point threshold, no file write operation is currently being performed, the current analog-to-digital converter's sampling task is in the allowed sampling point compensation state, the current GNSS module is not abnormal, and the current second pulse signal is not abnormal, then based on the number of discrete compensation points, the number of sampling points is periodically boundary discretely compensated in the next second pulse signal period. According to the filter frequency offset error rate, the cumulative error variable is accumulated point by point in the next second pulse signal period, and when the absolute value of the cumulative error variable is greater than or equal to 1, single-point compensation of the number of sampling points is triggered. If the write pointer of the current buffer goes out of bounds, the current buffer does not have enough space, the number of discrete compensation points exceeds the preset compensation point threshold, a file write operation is currently being performed, the current analog-to-digital converter's sampling task is not in the allowed sampling point compensation state, the current GNSS module is abnormal, or the current second pulse signal is abnormal, then the sampling point compensation step is skipped.

[0015] Secondly, the present invention provides a sampling point compensation device based on second pulse frequency offset, comprising: The read unit is used to read the count value of the local timer when the current second pulse signal arrives in high-speed external bypass mode; The first calculation unit is used to calculate the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period based on the difference between the count value of the local timer between the current second pulse signal and the previous second pulse signal. The determining unit is used to determine the frequency offset error rate of the current second pulse signal period based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period, or the actual number of sampling points of the analog-to-digital converter and the theoretical number of sampling points within the current second pulse signal period. The actual number of sampling points within the second pulse signal period refers to the total number of valid data points in the buffer of the analog-to-digital converter within the second pulse signal period. The discrimination and filtering unit is used to effectively discriminate the frequency offset error rate of the current second pulse signal period, and to perform multi-cycle smoothing filtering on the discriminated effective frequency offset error rate to obtain the filtered frequency offset error rate. The second calculation unit is used to calculate the difference between the theoretical number of sampling points and the actual number of sampling points of the analog-to-digital converter in the current second pulse signal period, and to obtain the number of discrete compensation points. The compensation unit is used to perform periodic boundary discrete compensation on the number of sampling points in the next second pulse signal period based on the number of discrete compensation points. It accumulates the cumulative error variable for each sampling point in the next second pulse signal period according to the filter frequency offset error rate, and triggers single-point compensation of the number of sampling points when the absolute value of the cumulative error variable is greater than or equal to 1.

[0016] Thirdly, the present invention provides a node-type seismic acquisition instrument, comprising a memory, a processor, and a transceiver connected in sequence and in communication, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the sampling point compensation method based on second pulse frequency offset as described in the first aspect or any possible design of the first aspect.

[0017] Fourthly, the present invention provides a computer-readable storage medium storing instructions that, when executed on a computer, perform the sampling point compensation method based on second pulse frequency offset as described in the first aspect or any possible design of the first aspect.

[0018] Fifthly, the present invention provides a computer program product containing instructions that, when executed on a computer, cause the computer to perform the sampling point compensation method based on second pulse frequency offset as described in the first aspect or any possible design of the first aspect.

[0019] Beneficial effects: This invention discloses a sampling point compensation scheme based on the second pulse frequency offset, which can solve the problems of cumulative sampling errors caused by the local sampling clock being affected by crystal oscillator frequency offset, power supply status, and long-term operation, leading to inconsistencies between the theoretical and actual number of sampling points, time stamp offset of sampling data, and decreased alignment accuracy of multi-node data in the later stages. Specifically, in high-speed external bypass mode, the count value of the local timer when the current second pulse signal arrives is read; the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period is calculated based on the difference between the count value of the local timer and the previous second pulse signal; based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period and the theoretical frequency of the local high-stability crystal oscillator, or the actual number of sampling points of the analog-to-digital converter within the current second pulse signal period and the theoretical number of sampling points, the frequency offset error rate of the current second pulse signal period is determined. Here, the actual number of sampling points within the second pulse signal period refers to the number of sampling points in the second pulse signal period. The system calculates the total number of valid data points in the analog-to-digital converter's buffer within a given period; it effectively determines the frequency offset error rate of the current second pulse signal period and performs multi-period smoothing filtering on the determined valid frequency offset error rate to obtain the filtered frequency offset error rate; it calculates the difference between the theoretical number of sampling points and the actual number of sampling points of the analog-to-digital converter in the current second pulse signal period to obtain the discrete compensation points; based on the discrete compensation points, it performs period boundary discrete compensation on the number of sampling points in the next second pulse signal period, and accumulates the cumulative error variable for each sampling point in the next second pulse signal period according to the filtered frequency offset error rate, triggering single-point compensation of the number of sampling points when the absolute value of the accumulated error variable is greater than or equal to 1. In this way, the GNSS second pulse can be extended from a simple system timing signal to a local sampling clock frequency offset observation reference. The frequency offset error rate is obtained by the difference in timer count values ​​between adjacent second pulse signals, which can quantify the deviation of the local crystal oscillator relative to the GNSS time reference. Simultaneously, this invention explicitly integrates the high-speed external clock / local high-stability crystal oscillator, local timer, controller clock output, and analog-to-digital converter sampling clock into the same clock link. This establishes a direct link between the high-speed external clock frequency of the local high-stability crystal oscillator and the sampling point error of the analog-to-digital converter, rather than merely remaining at the RTC or system time level. This achieves a closed-loop compensation mechanism for sampling points, combining the second pulse signal, local calculator, frequency offset filtering, sampling point statistics, and data write-to-disk process. Secondly, before sampling point compensation, effective discrimination is performed based on the frequency offset error rate, and multi-cycle smoothing filtering is applied to the effective frequency offset error rate. This ensures that the compensation algorithm is not directly affected by a single abnormal PPS, counting jitter, or interruption delay, improving the stability of the frequency offset input and the reliability of the compensation action. Furthermore, this invention employs a combination of period boundary discrete compensation and dynamic compensation within the second pulse signal period. This not only eliminates the accumulated error of the previous second pulse signal period when the second pulse signal period switches but also gradually disperses the frequency offset error within the second pulse signal period, reducing the risk of sudden changes caused by concentrated compensation.Finally, this invention is applicable to nodal seismic acquisition tasks under intermittent GNSS operation or short-term lockout conditions, which helps to reduce power consumption during continuous GNSS operation and improve the time consistency of long-term unattended acquisition.

[0020] Furthermore, this invention determines whether to skip the sampling point compensation step by judging whether the current buffer's write pointer will go out of bounds, whether the current buffer has enough space, whether the number of discrete compensation points exceeds the preset compensation point threshold, whether a file write operation is currently being performed, whether the current analog-to-digital converter's sampling task is in a state where sampling point compensation is allowed, whether the current GNSS module is abnormal, and whether the current second pulse signal is abnormal. This makes the sampling point compensation compatible with the ADC interrupt sampling, RTOS task scheduling, data buffering, and file write process, avoiding new data anomalies caused by the compensation operation. Attached Figure Description

[0021] Figure 1 A flowchart illustrating the sampling point compensation method based on second pulse frequency offset provided in this application embodiment; Figure 2 A block diagram of a sampling point compensation device based on second pulse frequency offset provided in an embodiment of this application; Figure 3 This is a block diagram of a nodal seismic acquisition instrument provided in an embodiment of this application. Detailed Implementation

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in conjunction with the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following description of the structure of the accompanying drawings is only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0023] It should be understood that although the terms first, second, etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit, without departing from the scope of the exemplary embodiments of the invention.

[0024] It should be understood that the term "and / or" that may appear in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" that may appear in this document describes another relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " that may appear in this document generally indicates that the related objects before and after it are in an "or" relationship.

[0025] It should be understood that specific details are provided in the following description to facilitate a complete understanding of the exemplary embodiments. However, those skilled in the art will understand that the exemplary embodiments can be implemented without these specific details. For example, the system may be shown in block diagrams to avoid obscuring the example with unnecessary details. In other instances, well-known processes, structures, and techniques may be shown without unnecessary details to avoid obscuring the exemplary embodiments.

[0026] To achieve sampling point error compensation for nodal seismic acquisition instruments, this application provides a sampling point compensation method, device, medium, and product based on second pulse frequency offset. This sampling point compensation method, device, medium, and product based on second pulse frequency offset can solve the problems of cumulative sampling errors caused by the local sampling clock being affected by crystal oscillator frequency offset, power supply status, and long-term operation, which in turn leads to inconsistencies between the theoretical and actual number of sampling points, offset of sampling data time stamps, and decreased alignment accuracy of multi-node data in the later stages.

[0027] The sampling point compensation method based on second pulse frequency offset provided in this application can be applied to nodal seismic acquisition instruments. It is understood that the execution entity described does not constitute a limitation on the embodiments of this application.

[0028] The sampling point compensation method based on second pulse frequency offset provided in the embodiments of this application will be described in detail below.

[0029] like Figure 1 The diagram shown is a flowchart of a sampling point compensation method based on second pulse frequency offset provided in the first aspect of the present application. The sampling point compensation method based on second pulse frequency offset may include the following steps S101-S106.

[0030] Step S101. In high-speed external bypass mode, read the count value of the local timer when the current second pulse signal arrives.

[0031] In one or more embodiments, the GNSS module can be started and GNSS timing initialization can be performed after the node seismic acquisition instrument is powered on or woken up from a low-power state.

[0032] Specifically, the main control MCU of the nodal seismic acquisition instrument can activate the GNSS module and wait for the GNSS to output a valid time message and a stable PPS signal. The control system of the nodal seismic acquisition instrument can determine whether time synchronization is available based on the satellite lock status, the validity of the time message, and the PPS output status. After receiving the Recommended Minimum Specific GNSS Data (GNRMC) message from GNSS, the control system can start a basic timer as a PPS time synchronization window timer. When the basic timer runs, the counting frequency (e.g., 10 kHz) and overflow period (e.g., 1.5 seconds) are dynamically configured to ensure that PPS time synchronization is completed within the overflow period window after receiving the GNSS message. If PPS arrives, the basic timer is cleared and stopped; if the window times out, the PPS timeout or time synchronization error process is entered.

[0033] After completing the GNSS timing initialization, the system clock of the nodal seismic acquisition instrument can be switched to High-Speed ​​External Bypass Mode (HSE), making the system clock SYSCLK equal to 16.384 MHz, and the frequencies of the Advanced High-performance Bus (AHB) clock (HCLK) and the Advanced Peripheral Bus (APB) clocks (including PCLK1, PCLK2, and PCLK3) equal to the system clock. At this time, the local timer (TIM2) counting frequency is approximately 16.384 MHz, which can directly reflect the actual frequency of HSE within a 1-second PPS gate.

[0034] Step S102. Calculate the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period based on the difference between the count value of the local timer between the current second pulse signal and the previous second pulse signal.

[0035] In one or more embodiments, when the rising edge of the current second pulse signal arrives at the external interrupt input of the MCU, the MCU enters the interrupt service routine and immediately reads the current count value of the local timer, and uses it as the count value of the local timer when the second pulse signal arrives.

[0036] In one or more embodiments, after reading the count value of the local timer when the current second pulse signal arrives, it can be determined whether the local timer counter will overflow between the current second pulse signal and the previous second pulse signal. If the local timer counter will not overflow between the current second pulse signal and the previous second pulse signal, the difference between the local timer count values ​​between the current second pulse signal and the previous second pulse signal is determined according to the following formula.

[0037] C_k = Count_k - Count_{k-1} If the local timer counter overflows between the current second pulse signal and the previous second pulse signal, the difference between the local timer count value between the current second pulse signal and the previous second pulse signal is determined according to the following formula.

[0038] C_k=Count_k+Count_max-Count_{k-1} Where Count_k represents the count value of the local timer when the current second pulse signal arrives, Count_{k-1} represents the count value of the local timer when the previous second pulse signal arrives, and Count_max represents the maximum count value of the local timer.

[0039] Then, based on the difference between the count value of the local timer between the current second pulse signal and the previous second pulse signal, the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period is calculated according to the following formula.

[0040] HSE_Actual_Fq,k=C_k / T_pps Where T_pps represents the duration corresponding to the current second pulse signal period, which is generally 1 second.

[0041] Step S103. Based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period, or the actual number of sampling points of the analog-to-digital converter and the theoretical number of sampling points within the current second pulse signal period, determine the frequency offset error rate of the current second pulse signal period.

[0042] The actual number of sampling points within the second pulse signal period refers to the total number of valid data points in the buffer of the analog-to-digital converter within the second pulse signal period.

[0043] Frequency offset error rate has two sources at different operating stages.

[0044] First source: If the main control system of the nodal seismic acquisition instrument is currently in the taming phase, the frequency offset error rate of the current second pulse signal period is determined according to the following formula based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period.

[0045] TimeErrorRate_k=(HSE_Actual_Fq,k-HSE_THEORY_FQ) / HSE_Actual_Fq,k Wherein, HSE_Actual_Fq,k represents the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period, and HSE_THEORY_FQ represents the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period, which is generally defined as 16384000Hz.

[0046] The formula uses HSE_Actual_Fq,k as the denominator. If HSE_Actual_Fq,k is greater than HSE_THEORY_FQ, then TimeErrorRate_k is positive, indicating that the measured frequency is higher than the theoretical frequency, the local clock is faster, and the number of sampling points in the actual time is too high. Subsequent compensation actions should tend to reduce the number of sampling points. If HSE_Actual_Fq,k is less than HSE_THEORY_FQ, then TimeErrorRate_k is negative, indicating that the local clock is slower, and the number of sampling points in the actual time is too low. Subsequent compensation actions should tend to increase the number of sampling points.

[0047] Second source: If the main control system of the nodal seismic acquisition instrument is currently in the stable phase after the taming phase, the frequency offset error rate of the current second pulse signal period is determined according to the following formula based on the actual number of sampling points and the theoretical number of sampling points of the analog-to-digital converter in the current second pulse signal period.

[0048] TimeErrorRate_k=(N_a,k-N_t,k) / N_a,k Where N_a,k represents the actual number of sampling points of the analog-to-digital converter within the current second pulse signal period, and N_t,k represents the theoretical number of sampling points of the analog-to-digital converter within the current second pulse signal period. The conditions for determining the frequency offset error rate through the second source include: the system has completed the initial "second pulse discipline" process and entered a long-term stable "period measurement / normal operation" phase; the absolute value of the difference between the actual number of sampling points and the theoretical number of sampling points is greater than 2; and the frequency offset error rate does not exceed 0.002, i.e., the frequency offset error rate does not exceed 2000pp.

[0049] The frequency deviation error rate TimeErrorRate_k of the current second pulse signal period can also be converted to ppm or ppb: ppm_k = TimeErrorRate_k × 10 6 ppb_k = TimeErrorRate_k × 10 9 Where ppm_k represents one part per million of frequency deviation, and ppb_k represents one part per billion of frequency deviation.

[0050] Step S104. Effectively determine the frequency offset error rate of the current second pulse signal period, and perform multi-cycle smoothing filtering on the determined effective frequency offset error rate to obtain the filtered frequency offset error rate.

[0051] In one or more embodiments, when making a valid determination, it can be determined whether the absolute value of the frequency offset error rate of the current second-pitch signal period exceeds a first preset error rate threshold. If it does not exceed the first preset error rate threshold, the frequency offset error rate of the current second-pitch signal period is determined to be valid. That is, if |TimeErrorRate|≤r_limit, the frequency offset error rate of the current second-pitch signal period is determined to be valid, where r_limit represents the first preset error rate threshold. The value of r_limit can be 0.002, i.e., 2000ppm.

[0052] Alternatively, it can be determined whether the absolute value of the frequency offset error rate difference between the current second-count signal cycle and the previous second-count signal cycle, and the valid frequency offset error rate difference of the previous second-count signal cycle, exceeds a second preset error rate threshold. If it does not exceed the second preset error rate threshold, the frequency offset error rate of the current second-count signal cycle is considered valid. Here, the frequency offset error rate difference of the previous second-count signal cycle is the difference between the frequency offset error rate of the previous second-count signal cycle and the frequency offset error rate of the adjacent second-count signal cycles preceding the previous second-count signal cycle. The second preset error rate threshold can be set to 100 ppm. If it exceeds the second preset error rate threshold, it can be considered that the second-count signal cycle has PPS jitter, counting abnormalities, or short-term state switching.

[0053] If the frequency offset error rate of the most recent consecutive second-pitch signal cycles is invalid, the clock state of the analog-to-digital converter is marked as abnormal. If the frequency offset error rate of at least one of the most recent consecutive second-pitch signal cycles is valid, the average of the frequency offset error rates of the most recent consecutive valid second-pitch signal cycles is calculated to obtain the filtered frequency offset error rate; wherein, the valid second-pitch signal cycle is the second-pitch signal cycle in which the frequency offset error rate is valid. The most recent consecutive second-pitch signal cycles can be, but are not limited to, the most recent consecutive 3 or 4 second-pitch signal cycles, which can be set according to the actual situation.

[0054] Step S105. Calculate the difference between the theoretical number of sampling points and the actual number of sampling points of the analog-to-digital converter in the current second pulse signal period to obtain the number of discrete compensation points.

[0055] The theoretical number of sampling points of the analog-to-digital converter in the current second pulse signal period can be determined based on the duration of the current second pulse signal period and the sampling frequency of the analog-to-digital converter. For example, if the duration of the current second pulse signal period is 1 second and the sampling frequency of the analog-to-digital converter is 1000 Hz, then the theoretical number of sampling points of the analog-to-digital converter in the current second pulse signal period is 1000 × 1 = 1000.

[0056] Step S106. Based on the number of discrete compensation points, perform period boundary discrete compensation on the number of sampling points in the next second pulse signal period. According to the filter frequency offset error rate, accumulate the cumulative error variable for each sampling point in the next second pulse signal period, and trigger single-point compensation of the number of sampling points when the absolute value of the cumulative error variable is greater than or equal to 1.

[0057] In one or more embodiments, when performing period boundary discrete compensation on the number of sampling points in the next second pulse signal cycle, the compensation can be performed once at the beginning of the next second pulse signal cycle based on the discrete compensation point count, or it can be performed when the buffer switches and the current sampling pointer is in the initial position or other safe position. If the discrete compensation point count is positive, it indicates that the number of sampling points in the previous second pulse signal cycle was too low. The system can add a compensation point by copying the data of the previous physical sampling point. This compensation point will be written to the buffer and pushed to disk along with the normal data. If the discrete compensation point count is negative, it indicates that the number of sampling points in the previous second pulse signal cycle was too high. The system can skip a sampling point by backtracking, thereby reducing the effective sampling points.

[0058] In one or more embodiments, when accumulating the cumulative error variable point-by-point within the next second pulse signal period and triggering single-point compensation of the number of sampling points, the cumulative error variable can be accumulated point-by-point within the next second pulse signal period according to the filter frequency offset error rate. When the absolute value of the cumulative error variable is greater than or equal to 1 and the cumulative error variable is positive, the number of sampling points is increased by one and the increased number of sampling points is written to the buffer. When the absolute value of the cumulative error variable is greater than or equal to 1 and the cumulative error variable is negative, the control buffer write pointer is pushed back by one sampling point. After single-point compensation, the accumulated error variable retains the remainder and continues to participate in subsequent accumulations. For example, when the accumulated error variable is 1.23, after performing sequential reduction of sampling points compensation, the accumulated error variable becomes 0.23. This accumulated error variable of 0.23 is retained and continues to participate in subsequent accumulations.

[0059] In one or more embodiments, before performing periodic boundary discrete compensation and triggering single-point compensation of the number of sampling points, it is also possible to determine whether the write pointer of the current buffer will go out of bounds, whether the current buffer has enough space, whether the number of discrete compensation points exceeds the preset compensation point threshold, whether a file write operation is currently being performed, whether the current analog-to-digital converter's sampling task is in a state where sampling point compensation is allowed, whether the current GNSS module is abnormal, and whether the current second pulse signal is abnormal.

[0060] In the next second pulse signal cycle, periodic boundary discrete compensation is performed on the number of sampling points. Based on the filter frequency offset error rate, the cumulative error variable is accumulated point by point within the next second pulse signal cycle. Single-point compensation of the number of sampling points is triggered when the absolute value of the accumulated error variable is greater than or equal to 1. If the write pointer of the current buffer does not exceed the bounds, the current buffer has sufficient space, the number of discrete compensation points does not exceed the preset compensation point threshold, no file write operation is currently being performed, the current analog-to-digital converter's sampling task is in a state where sampling point compensation is allowed, the current GNSS module is not abnormal, and the current second pulse signal is not abnormal, then based on the number of discrete compensation points, periodic boundary discrete compensation is performed on the number of sampling points in the next second pulse signal cycle. Based on the filter frequency offset error rate, the cumulative error variable is accumulated point by point within the next second pulse signal cycle. Single-point compensation of the number of sampling points is triggered when the absolute value of the accumulated error variable is greater than or equal to 1. If the write pointer of the current buffer goes out of bounds, the current buffer does not have enough space, the number of discrete compensation points exceeds the preset compensation point threshold, a file write operation is currently being performed, the current analog-to-digital converter's sampling task is not in the allowed sampling point compensation state, the current GNSS module is abnormal, or the current second pulse signal is abnormal, then the sampling point compensation step is skipped.

[0061] In one or more embodiments, during the sampling point compensation process, the system may record clock compensation-related information in the sampling data file, status file, or operation log. The recorded content may include, but is not limited to, device number, sampling rate, start timestamp, sample number, GNSS status, PPS validity status, frequency offset error rate, filtered frequency offset error rate, number of discrete compensation points, cumulative error variable, anomaly flags, and file-level clock status.

[0062] In summary, the sampling point compensation method based on second pulse frequency offset provided by this invention reads the count value of the local timer when the current second pulse signal arrives in high-speed external bypass mode; calculates the measured high-speed external clock frequency of the local high-stability crystal oscillator within the current second pulse signal period based on the difference between the count value of the local timer and the previous second pulse signal; and determines the frequency offset error rate of the current second pulse signal period based on the measured high-speed external clock frequency of the local high-stability crystal oscillator within the current second pulse signal period and the theoretical frequency of the local high-stability crystal oscillator, or the actual number of sampling points of the analog-to-digital converter within the current second pulse signal period and the theoretical number of sampling points. The actual sampling point frequency within the second pulse signal period is... The number of sampling points refers to the total number of valid data points in the buffer of the analog-to-digital converter (ADC) within the second pulse signal period. The frequency offset error rate of the current second pulse signal period is effectively determined, and multi-cycle smoothing filtering is applied to the determined valid frequency offset error rate to obtain the filtered frequency offset error rate. The difference between the theoretical number of sampling points and the actual number of sampling points of the ADC in the current second pulse signal period is calculated to obtain the discrete compensation points. Based on the discrete compensation points, period boundary discrete compensation is performed on the number of sampling points in the next second pulse signal period. According to the filtered frequency offset error rate, the cumulative error variable is accumulated point by point in the next second pulse signal period, and single-point compensation of the number of sampling points is triggered when the absolute value of the cumulative error variable is greater than or equal to 1. In this way, the GNSS second pulse can be extended from a simple system timing signal to a local sampling clock frequency offset observation reference. The frequency offset error rate is obtained by the difference in timer count values ​​between adjacent second pulse signals, which can quantify the deviation of the local crystal oscillator relative to the GNSS time reference. Simultaneously, by explicitly incorporating the high-speed external clock / local high-stability crystal oscillator, local timer, controller clock output, and analog-to-digital converter (ADC) sampling clock into the same clock link, a direct link can be established between the high-speed external clock frequency of the local high-stability crystal oscillator and the ADC sampling point error, rather than merely remaining at the RTC or system time level. This achieves a closed-loop compensation mechanism for sampling points, combining the second pulse signal, local calculator, frequency offset filtering, sampling point statistics, and data write-to-disk process. This addresses the problem of accumulated sampling errors caused by crystal oscillator frequency offset, power supply status, and long-term operation affecting the local sampling clock, leading to discrepancies between the theoretical and actual number of sampling points, time stamp offset of sampled data, and decreased alignment accuracy of multi-node data in the later stages. Secondly, before sampling point compensation, effective discrimination is performed through the frequency offset error rate, and multi-cycle smoothing filtering is applied to the effective frequency offset error rate. This ensures that the compensation algorithm is not directly affected by a single abnormal PPS, counting jitter, or interruption delay, improving the stability of the frequency offset input and the reliability of the compensation action. Furthermore, the present invention adopts a combination of periodic boundary discrete compensation and dynamic compensation within the second pulse signal period. This not only eliminates the cumulative error of the previous second pulse signal period when the second pulse signal period switches, but also gradually disperses the frequency offset error within the second pulse signal period, reducing the risk of sudden changes caused by concentrated compensation.Furthermore, this invention is applicable to node-based seismic acquisition tasks under intermittent GNSS operation or short-term lockout conditions, helping to reduce power consumption during continuous GNSS operation and improve the time consistency of long-term unattended acquisition. Further, this invention determines whether to skip the sampling point compensation step by judging whether the current buffer's write pointer will exceed the limit, whether the current buffer has sufficient space, whether the number of discrete compensation points exceeds the preset compensation point threshold, whether a file write operation is currently being performed, whether the current analog-to-digital converter's sampling task is in a state where sampling point compensation is allowed, whether the current GNSS module is abnormal, and whether the current second pulse signal is abnormal. This ensures that the sampling point compensation is compatible with the ADC interrupt sampling, RTOS task scheduling, data buffering, and file write process, avoiding new data anomalies caused by the compensation operation. Finally, by recording GNSS status, PPS validity status, frequency offset error rate, filter frequency offset error rate, number of discrete compensation points, cumulative error variables, and anomaly flags, the sampling point compensation process can be traced, facilitating subsequent data quality control and equipment status analysis.

[0063] Please see Figure 2 The second aspect of this application provides a sampling point compensation device based on second pulse frequency offset, comprising: The read unit is used to read the count value of the local timer when the current second pulse signal arrives in high-speed external bypass mode; The first calculation unit is used to calculate the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period based on the difference between the count value of the local timer between the current second pulse signal and the previous second pulse signal. The determining unit is used to determine the frequency offset error rate of the current second pulse signal period based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period, or the actual number of sampling points of the analog-to-digital converter and the theoretical number of sampling points within the current second pulse signal period. The actual number of sampling points within the second pulse signal period refers to the total number of valid data points in the buffer of the analog-to-digital converter within the second pulse signal period. The discrimination and filtering unit is used to effectively discriminate the frequency offset error rate of the current second pulse signal period, and to perform multi-cycle smoothing filtering on the discriminated effective frequency offset error rate to obtain the filtered frequency offset error rate. The second calculation unit is used to calculate the difference between the theoretical number of sampling points and the actual number of sampling points of the analog-to-digital converter in the current second pulse signal period, and to obtain the number of discrete compensation points. The compensation unit is used to perform periodic boundary discrete compensation on the number of sampling points in the next second pulse signal period based on the number of discrete compensation points. It accumulates the cumulative error variable for each sampling point in the next second pulse signal period according to the filter frequency offset error rate, and triggers single-point compensation of the number of sampling points when the absolute value of the cumulative error variable is greater than or equal to 1.

[0064] The working process, working details and technical effects of the sampling point compensation device based on second pulse frequency offset provided in the second aspect of this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0065] Please see Figure 3 The third aspect of this application provides a node-type seismic acquisition instrument, including a memory, a processor, and a transceiver that are connected in sequence. The memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the sampling point compensation method based on second pulse frequency offset as described in the first aspect of the application.

[0066] For specific examples, the memory may include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out memory (FIFO), and / or last-in-first-out memory (FILO), etc.; the processor may be, but is not limited to, microprocessors of the STM32F105 series, ARM (Advanced RISC Machines), x86 architecture processors, or processors with integrated NPU (neural-network processing units); the transceiver may be a GNSS timing module.

[0067] This fourth aspect of the embodiment provides a computer-readable storage medium storing instructions containing the sampling point compensation method based on second pulse frequency offset as described in the first aspect of the embodiment. Specifically, the computer-readable storage medium stores instructions that, when executed on a computer, perform the sampling point compensation method based on second pulse frequency offset as described in the first aspect. The computer-readable storage medium refers to a data storage medium, which may include, but is not limited to, floppy disks, optical disks, hard disks, flash memory, USB flash drives, and / or Memory Sticks. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0068] The fifth aspect of this embodiment provides a computer program product containing instructions that, when executed on a computer, cause the computer to perform the sampling point compensation method based on second pulse frequency offset as described in the first aspect of the embodiment, wherein the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.

[0069] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sampling point compensation method based on second pulse frequency offset, applied to a nodal seismic acquisition instrument, characterized in that, include: In high-speed external bypass mode, read the count value of the local timer when the current second pulse signal arrives; The measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period is calculated based on the difference between the count value of the local timer between the current second pulse signal and the previous second pulse signal. Based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period, or the actual number of sampling points of the analog-to-digital converter within the current second pulse signal period and the theoretical number of sampling points, the frequency offset error rate of the current second pulse signal period is determined. The actual number of sampling points within the second pulse signal period refers to the total number of valid data points in the buffer of the analog-to-digital converter within the second pulse signal period. The frequency offset error rate of the current second pulse signal period is effectively determined, and the determined effective frequency offset error rate is subjected to multi-cycle smoothing filtering to obtain the filtered frequency offset error rate. The number of discrete compensation points is obtained by calculating the difference between the theoretical number of sampling points and the actual number of sampling points of the analog-to-digital converter in the current second pulse signal period; Based on the number of discrete compensation points, the number of sampling points is periodically boundary discretely compensated in the next second pulse signal period. According to the filter frequency offset error rate, the cumulative error variable is accumulated point by point in the next second pulse signal period, and when the absolute value of the cumulative error variable is greater than or equal to 1, the single-point compensation of the number of sampling points is triggered.

2. The sampling point compensation method based on second pulse frequency offset according to claim 1, characterized in that, Before reading the count value of the local timer when the current second pulse signal arrives, the method further includes: After the nodal seismic acquisition instrument is powered on or woken up from a low-power state, the GNSS module is started and GNSS timing initialization is performed; Switch the system clock of the nodal seismic acquisition instrument to high-speed external bypass mode.

3. The sampling point compensation method based on second pulse frequency offset according to claim 1, characterized in that, After reading the count value of the local timer when the current second pulse signal arrives, the method further includes: Determine whether the local timer counter will overflow between the current second pulse signal and the previous second pulse signal; If the local timer counter does not overflow between the current second pulse signal and the previous second pulse signal, the difference between the count values ​​of the local timer between the current second pulse signal and the previous second pulse signal is determined according to the following formula; C_k = Count_k - Count_{k-1} If the local timer counter overflows between the current second pulse signal and the previous second pulse signal, the difference between the local timer count value between the current second pulse signal and the previous second pulse signal is determined according to the following formula; C_k=Count_k+Count_max-Count_{k-1} Where Count_k represents the count value of the local timer when the current second pulse signal arrives, Count_{k-1} represents the count value of the local timer when the previous second pulse signal arrives, and Count_max represents the maximum count value of the local timer. Based on the difference between the count value of the local timer between the current second pulse signal and the previous second pulse signal, the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period is calculated according to the following formula. HSE_Actual_Fq,k=C_k / T_pps Where T_pps represents the duration corresponding to the current second pulse signal period.

4. The sampling point compensation method based on second pulse frequency offset according to claim 3, characterized in that, Based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period, or the actual number of sampling points of the analog-to-digital converter and the theoretical number of sampling points within the current second pulse signal period, the frequency offset error rate of the current second pulse signal period is determined, including: If the main control system of the nodal seismic acquisition instrument is currently in the taming phase, the frequency offset error rate of the current second pulse signal period is determined according to the following formula based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period. TimeErrorRate_k=(HSE_Actual_Fq,k-HSE_THEORY_FQ) / HSE_Actual_Fq,k Where HSE_Actual_Fq,k represents the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period, and HSE_THEORY_FQ represents the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period; If the main control system of the nodal seismic acquisition instrument is currently in the stable phase after the taming phase, the frequency offset error rate of the current second pulse signal period is determined according to the following formula based on the actual number of sampling points and the theoretical number of sampling points of the analog-to-digital converter in the current second pulse signal period; TimeErrorRate_k=(N_a,k-N_t,k) / N_a,k Where N_a,k represents the actual number of sampling points of the analog-to-digital converter within the current second pulse signal period, and N_t,k represents the theoretical number of sampling points of the analog-to-digital converter within the current second pulse signal period.

5. The sampling point compensation method based on second pulse frequency offset according to claim 1, characterized in that, The frequency offset error rate of the current second-pulse signal period is effectively determined, and the determined effective frequency offset error rate is subjected to multi-cycle smoothing filtering to obtain the filtered frequency offset error rate, including: Determine whether the absolute value of the frequency offset error rate of the current second-pulse signal period exceeds a first preset error rate threshold. If it does not exceed the first preset error rate threshold, then the frequency offset error rate of the current second-pulse signal period is determined to be valid; or Determine whether the absolute value of the frequency offset error rate difference between the current second-count signal cycle and the previous second-count signal cycle exceeds a second preset error rate threshold. If it does not exceed the second preset error rate threshold, then the frequency offset error rate of the current second-count signal cycle is determined to be valid. The frequency offset error rate difference of the previous second-count signal cycle is the difference between the frequency offset error rate of the previous second-count signal cycle and the frequency offset error rate of the adjacent second-count signal cycle before the previous second-count signal cycle. If the frequency offset error rate of several consecutive second pulse signal cycles is invalid, then mark the clock state of the analog-to-digital converter as abnormal. If the frequency offset error rate of at least one of the most recent consecutive second-shot signal cycles is valid, then the average value of the frequency offset error rates of the most recent consecutive valid second-shot signal cycles is calculated to obtain the filtered frequency offset error rate; wherein, the valid second-shot signal cycle is the second-shot signal cycle in which the frequency offset error rate is valid.

6. The sampling point compensation method based on second pulse frequency offset according to claim 1, characterized in that, Based on the number of discrete compensation points, period boundary discrete compensation is performed on the number of sampling points in the next second pulse signal period, including: Based on the discrete compensation points, a one-time sampling point compensation is performed at the beginning of the next second pulse signal cycle; Based on the filter frequency offset error rate, the cumulative error variable is accumulated point by point within the next second pulse signal period, and single-point compensation of the sampling point number is triggered when the absolute value of the cumulative error variable is greater than or equal to 1, including: The cumulative error variable is accumulated point by point within the next second pulse signal period based on the filter frequency offset error rate; When the absolute value of the cumulative error variable is greater than or equal to 1 and the cumulative error variable is positive, then the number of sampling points is increased by one and the increased number of sampling points is written to the buffer. When the absolute value of the cumulative error variable is greater than or equal to 1 and the cumulative error variable is negative, the control buffer write pointer is pushed back by one sampling point.

7. The sampling point compensation method based on second pulse frequency offset according to claim 1, characterized in that, Before performing periodic boundary discrete compensation and triggering single-point compensation of the number of sampling points, the method further includes: Determine whether the write pointer of the current buffer will go out of bounds, whether the current buffer has enough space, whether the number of discrete compensation points exceeds the preset compensation point threshold, whether a file write operation is currently being performed, whether the current analog-to-digital converter sampling task is in the allowed sampling point compensation state, whether the current GNSS module is abnormal, and whether the current second pulse signal is abnormal. The method, based on the number of discrete compensation points, performs periodic boundary discrete compensation on the number of sampling points in the next second pulse signal period. It accumulates the cumulative error variable point-by-point within the next second pulse signal period according to the filter frequency offset error rate, and triggers single-point compensation of the number of sampling points when the absolute value of the cumulative error variable is greater than or equal to 1. This includes: If the write pointer of the current buffer does not go out of bounds, the current buffer has enough space, the number of discrete compensation points does not exceed the preset compensation point threshold, no file write operation is currently being performed, the current analog-to-digital converter's sampling task is in the allowed sampling point compensation state, the current GNSS module is not abnormal, and the current second pulse signal is not abnormal, then based on the number of discrete compensation points, the number of sampling points is periodically boundary discretely compensated in the next second pulse signal period. According to the filter frequency offset error rate, the cumulative error variable is accumulated point by point in the next second pulse signal period, and when the absolute value of the cumulative error variable is greater than or equal to 1, single-point compensation of the number of sampling points is triggered. If the write pointer of the current buffer goes out of bounds, the current buffer does not have enough space, the number of discrete compensation points exceeds the preset compensation point threshold, a file write operation is currently being performed, the current analog-to-digital converter's sampling task is not in the allowed sampling point compensation state, the current GNSS module is abnormal, or the current second pulse signal is abnormal, then the sampling point compensation step is skipped.

8. A sampling point compensation device based on second pulse frequency offset, characterized in that, include: The read unit is used to read the count value of the local timer when the current second pulse signal arrives in high-speed external bypass mode; The first calculation unit is used to calculate the measured frequency of the high-speed external clock of the local high-stability crystal oscillator within the current second pulse signal period based on the difference between the count value of the local timer between the current second pulse signal and the previous second pulse signal. The determining unit is used to determine the frequency offset error rate of the current second pulse signal period based on the measured frequency of the high-speed external clock of the local high-stability crystal oscillator and the theoretical frequency of the local high-stability crystal oscillator within the current second pulse signal period, or the actual number of sampling points of the analog-to-digital converter and the theoretical number of sampling points within the current second pulse signal period. The actual number of sampling points within the second pulse signal period refers to the total number of valid data points in the buffer of the analog-to-digital converter within the second pulse signal period. The discrimination and filtering unit is used to effectively discriminate the frequency offset error rate of the current second pulse signal period, and to perform multi-cycle smoothing filtering on the discriminated effective frequency offset error rate to obtain the filtered frequency offset error rate. The second calculation unit is used to calculate the difference between the theoretical number of sampling points and the actual number of sampling points of the analog-to-digital converter in the current second pulse signal period, and to obtain the number of discrete compensation points. The compensation unit is used to perform periodic boundary discrete compensation on the number of sampling points in the next second pulse signal period based on the number of discrete compensation points. It accumulates the cumulative error variable for each sampling point in the next second pulse signal period according to the filter frequency offset error rate, and triggers single-point compensation of the number of sampling points when the absolute value of the cumulative error variable is greater than or equal to 1.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when executed on a computer, perform the sampling point compensation method based on the second pulse frequency offset as described in any one of claims 1 to 7.

10. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or the instructions are executed by the computer, they implement the sampling point compensation method based on the second pulse frequency offset as described in any one of claims 1 to 7.

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