Time synchronization control method for geological exploration acquisition signals

Abstract

The invention relates to a time synchronization control method for geological exploration acquisition signals, and belongs to the technical field of second pulse signal time synchronization control between an exploration station and a satellite by using stably changing phase difference information between signals. According to the technical scheme, a stable and periodically-changed phase difference is formed between a frequency signal of a crystal oscillation source of an exploration station and an adjusting signal of the crystal oscillation source, integral operation is conducted on the phase difference, linear increasing voltage is formed, non-full-cycle time correction is conducted on pulse per second signals between the exploration station and a satellite by means of the stable and linear change characteristic of the voltage, and the time correction precision is improved. According to the method, the measurement resolution is high, the circuit structure is simple, the method is easy to implement, the counting error of + / -1 pulse existing in a common high-frequency counting method is greatly eliminated, the measurement accuracy is high, and the measurement accuracy is high. And high-precision time synchronization of the second pulse signal of the exploration station and the second pulse signal of the satellite is realized.

Description

Technical Field

[0001] The present invention relates to a time synchronization control method for geological exploration acquisition signals. The method utilizes the phase difference relationship between the frequency signal of an exploration station crystal oscillator source and its regulated frequency signal to perform multi-cycle pulse integration operations, and utilizes the linear growth of the integrated voltage to perform correction operations on the phase difference between second pulse signals, thereby achieving high-precision frequency control of the exploration station crystal oscillator source. The method belongs to the technical field of time synchronization control between the second pulse signal of the exploration station and the second pulse signal of the satellite by utilizing the phase difference information of the stably changing frequency signals. Background Art

[0002] Under the influence of factors such as harsh field environments and system design, if the acquisition and recording time of geological exploration stations is not synchronized with the excitation time, waste will be generated. Moreover, the higher the degree of synchronization between sampling points at the same time between geological exploration collection stations, the more accurate the synthesis of geological sampling data. Therefore, the key technology is clock synchronization between geological exploration stations. Due to the high precision of satellite clock timing, each exploration station uses the satellite clock as a reference time to achieve clock synchronization between exploration stations. A common method is to use the satellite data receiving module in each exploration station to output the satellite second pulse signal. The time signal of a high-stability crystal oscillator is divided and output as a second pulse signal. The phase difference between these two second pulse signals is calculated. Based on this phase difference, the microprocessor outputs a control voltage to adjust the output frequency of the crystal oscillator, aligning the second pulse signal of the high-stability crystal oscillator with the second pulse signal of the satellite, thus achieving clock synchronization between exploration stations. The important content of the above method is the calculation of the phase difference. The commonly used method is to fill the counting gate formed by the second pulse signal of the crystal oscillator and the second pulse signal of the satellite with a high-frequency pulse signal. The counter counts the high-frequency pulse signal. Assuming that the single cycle value of the high-frequency pulse signal is T and the count value of the counter is N, the phase difference is N×T. However, under ordinary counting conditions, it cannot be guaranteed that the counting gate contains exactly a full cycle of high-frequency pulse signals, that is, the common counting error problem of ±1 pulse limits the improvement of the phase difference measurement accuracy, and thus limits the time synchronization control accuracy between exploration stations. Summary of the Invention

[0003] The present invention aims to provide a time synchronization control method for geological exploration acquisition signals, specifically designed to address situations where the exploration station's pulse-second signal leads the satellite's pulse-second signal. By forming a stable, periodically changing phase difference between the frequency signal of the exploration station's crystal oscillator source and its regulated frequency signal, and integrating this phase difference to form a linearly increasing voltage, the stable, linearly increasing voltage is utilized to correct the non-integer period between the exploration station's pulse-second signal and the satellite's pulse-second signal. This significantly eliminates the ±1 pulse counting error present in conventional high-frequency counting methods, and then outputs a high-precision control voltage to adjust the frequency of the exploration station's crystal oscillator source, achieving synchronization between the exploration station's pulse-second signal and the satellite's pulse-second signal. The present invention has high measurement resolution, a simple circuit structure, and is easy to implement. It addresses the prior art issue of low phase difference accuracy between the exploration station's pulse-second signal and the satellite's pulse-second signal due to a ±1 pulse counting error.

[0004] The technical solution of the present invention is:

[0005] A time synchronization control method for geological exploration acquisition signals comprises the following steps:

[0006] ① Adjust the frequency value of the crystal oscillator source at the exploration station to generate a frequency signal f1. The frequency value of the frequency adjustment signal f1 has a small frequency deviation relationship with the frequency value of the frequency signal f0 of the crystal oscillator source, and the period value of the frequency signal f0 is T0;

[0007] In the time synchronization control system of the present invention, within a counting switch gate where the exploration station's Pulse-Seconds signal is out of sync with the satellite's Pulse-Seconds signal, the stable phase difference between the frequency signal of the exploration station's crystal oscillator source and the frequency signal generated by its frequency modulation is exploited to calculate a control voltage to adjust the crystal oscillator source's frequency, synchronizing the exploration station's Pulse-Seconds signal with the satellite's Pulse-Seconds signal, thus achieving a closed-loop control system. When the frequency values ​​of signal f1 and signal f0 have a small frequency deviation, the phase difference between the two frequency signals is stable, enabling linear calculation of the control voltage.

[0008] ② The exploration station's pulse-second signal is used as the counter's counting start signal, the satellite's pulse-second signal is used as the counter's counting end signal, and the exploration station's crystal oscillator source's frequency signal f0 is used as the counter's counting frequency signal;

[0009] ③ Use the staggered phase detector to perform phase detection on the counting frequency signal f0 and the frequency adjustment signal f1, observe the phase difference obtained by the phase detection, and adjust the small frequency deviation value to generate periodic step-by-step phase difference information;

[0010] The rising edge of the two frequency signals is used as the phase comparison moment, such as Figure 1As shown in the figure, assuming that f0 and f1 are initially in phase, the phases represented by the rising edges of signals f0 and f1 are compared once every cycle of the frequency signal, forming the time difference between the two rising edges, which is also the phase difference of the two frequency signals. From the perspective of time, the small frequency deviation between signals f0 and f1 means that there is a deviation in the period value of the two frequency signals. Therefore, the time difference between the two signals will increase with each cycle time, as shown in the figure. Figure 1 As shown, the phase difference It grows linearly. When the phase difference grows to the period value of signal f1, as Figure 1 As shown, the two frequency signals f0 and f1 coincide with each other again, and then the phases are compared again. The phase difference appears again, so the phase difference changes periodically in steps.

[0011] ④ Record the number of complete cycles n of the signal f0 in the periodic step-by-step phase difference information, and perform pulse integration on the periodic phase difference signal to obtain the maximum integrated voltage value U max ;

[0012] like Figure 1 As shown, the phase difference between the frequency signals It is a pulse square wave signal. The pulse integration operation is performed on this set of phase differences to obtain a linearly increasing voltage value. The maximum voltage value is U max Phase difference It is periodic, and the maximum voltage value U obtained by pulse integration operation is max It is also periodic, which provides voltage data for the correction calculation in the subsequent steps. From the analysis of the previous steps, we can see that if Figure 1 As shown, the phase comparison of signals f0 and f1 is periodic, and the signal It is a set of periodic phase differences. This set of phase difference information contains n periods of signal f0, and the next set of phase difference information also contains n periods of signal f0.

[0013] ⑤The voltage value U is measured in the counting switch max The number of counts is m, and the voltage value corresponding to the count end signal is U a The phase difference between the exploration station's pulse-second signal and the satellite's pulse-second signal is (m+U a / U max )×n×T0;

[0014] ⑥According to the phase difference (m+U a / U max )×n×T0, calculate the voltage control voltage value to adjust the output frequency of the crystal oscillator source.

[0015] In the counting switch, the voltage value U stored by the microcomputer controllermax The number of is m. In general, the arrival time of the satellite pulse-per-second signal as the counting end signal is not synchronized with the end time of the full cycle of the frequency signal f0 of the crystal oscillator source, and a correction operation is required. Figure 1 As shown in the figure, when the satellite second pulse signal arrives, the pulse integration operation for the phase difference stops, and the voltage value corresponding to the satellite second pulse signal is U a , the voltage value of the pulse integration operation increases linearly, such as Figure 1 As shown, the maximum voltage value U of an integral operation max The corresponding time is n×T0, then U a The corresponding time is (U a / U max )×n×T0, this periodic linear growth correction operation greatly reduces the counting error of ±1 pulse in the commonly used high-frequency pulse counting method. The phase difference between the exploration station second pulse signal and the satellite second pulse signal is as follows Figure 1 The total time in the counting gate shown is (m+U a / U max )×n×T0, the microcomputer controller outputs the control voltage according to the phase difference and adjusts the frequency of the crystal oscillator source of the exploration station, so that the second pulse signal of the exploration station is synchronized with the second pulse signal of the satellite. The system constitutes a time-synchronized closed-loop control.

[0016] The main innovation of the present invention is to use the stable periodic phase difference between the frequency signal of the exploration station crystal oscillator source and its regulated frequency signal, integrate the periodic phase difference to obtain a linearly increasing periodic voltage value, and then respectively calculate the integral period time m×n×T0 and the non-integer period time (U a / U max )×n×T0, the sum of the full cycle time and the non-full cycle time is the asynchronous time between the exploration station's second pulse signal and the satellite's second pulse signal, and a high-precision control voltage is output to adjust the exploration station's crystal oscillator source frequency. The present invention greatly eliminates the counting error of ±1 pulse existing in the commonly used high-frequency counting method, and can perform high-precision time synchronization control on the phase difference between the changing exploration station's second pulse signal and the satellite's second pulse signal.

[0017] The positive effects of the present invention are: the instrument structure is simple and easy to implement, and programmable control is introduced, so that the stable periodic phase difference information between the frequency signal of the exploration station crystal oscillator source and its adjustment frequency signal can be adjusted and the linear growth voltage obtained by the integral operation can be stored. The present invention has a wide time synchronization control range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1It is a schematic diagram of the phase difference change between frequency signals within the second signal gate of the present invention;

[0019] Figure 2 This is a block diagram of the time synchronization control system for geological exploration acquisition signals of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below by way of examples.

[0021] like Figure 2 As shown:

[0022] In this time synchronization control system, a microcomputer controller performs frequency adjustment so that the frequency value of the generated frequency signal f1 has a small frequency deviation relationship with the frequency value of the crystal oscillator source's frequency signal f0. A programmable logic device (CPLD) is used to program and control a staggered phase detector. The staggered phase detector performs phase detection on the counting frequency signal f0 and the frequency adjustment signal f1. When the frequency deviation between signals f0 and f1 is small, a regular phase difference variation is generated. By observing the detected phase difference and flexibly adjusting the small frequency deviation value, precise periodic step-by-step phase difference information is generated. This time synchronization control method, which utilizes this variation characteristic, has a higher resolution and accuracy than conventional frequency counting methods.

[0023] The present invention addresses situations where the exploration station's pulse-second signal precedes the satellite's pulse-second signal. The exploration station's pulse-second signal serves as the counter's count start signal, while the satellite's pulse-second signal serves as the counter's count end signal. The counter counts the frequency signal f0 from the crystal oscillator source. Within one phase difference cycle, the number of frequency signals f0 counted is n. This means that the number n of frequency signals f0 also varies with the periodic changes in the phase difference.

[0024] The microcomputer controller performs pulse integration operation on the periodic step-by-step phase difference signal, converting the periodic phase difference information into periodic voltage information. The linearly increasing integral voltage can be obtained by integrating the step-by-step phase difference. The microcomputer controller stores the maximum integral voltage U max The number m of and the number n of frequency signals f0.

[0025] The satellite second pulse signal triggers the counter to stop counting and the pulse integration operation. The integral voltage value at this time is U a , if U a Not equal to U max, indicating that the frequency signal f0 and the satellite second pulse signal do not arrive at the same time, and the microcomputer controller needs to perform correction calculations. Within the counting gate formed by the exploration station second pulse signal and the satellite second pulse signal, the number of full cycles of the frequency signal f0 is m×n, and the corresponding time is m×n×T0. According to the linear growth characteristics of the integrated voltage, the non-integer cycle time can be corrected more accurately. The non-integer cycle time is (U a / U max )×n×T0.

[0026] The microcomputer controller calculates the phase difference between the exploration station pulse-second signal and the satellite pulse-second signal as m×n×T0+(U a / U max )×n×T0. Based on the phase difference of the two-second pulse signal, the control voltage value U can be calculated. The microcomputer controller outputs this control voltage to control the frequency signal f0 of the crystal oscillator source of the exploration station, as shown in Figure 2 As shown in the figure, the entire system forms a closed-loop control system, which realizes the time synchronization control of the exploration station's second pulse signal and the satellite's second pulse signal, greatly reduces the counting error of ±1 pulse in the ordinary high-frequency counting method, and improves the control accuracy.

Claims

1. A time synchronization control method for geological exploration acquisition signals: ① Adjust the frequency value of the crystal oscillator source at the exploration station to generate a frequency signal f 1. This frequency adjustment signal f The frequency value of 1 is the same as the frequency signal of the crystal oscillator source f The frequency value of 0 has a small frequency deviation relationship, the frequency signal f The period value of 0 is T 0; ② The exploration station second pulse signal is used as the counting start signal of the counter, the satellite second pulse signal is used as the counting end signal of the counter, and the frequency signal of the exploration station crystal oscillator source is used as the counting end signal of the counter. f 0 is used as the counting frequency signal of the counter; ③Use the staggered phase detector to count the frequency signal f 0 and frequency adjustment signal f 1. Perform phase detection, observe the phase difference detected, and adjust the small frequency deviation value to generate periodic step-by-step phase difference information; ④ Record the signal in the periodic step-by-step phase difference information f The number of whole cycles of 0 n , and perform pulse integration on the periodic phase difference signal to obtain the maximum integrated voltage value U max ; ⑤The voltage value measured in the counting switch U max The number of m The voltage value corresponding to the counting end signal is U a , the phase difference between the exploration station's pulse-second signal and the satellite's pulse-second signal is ( m + U a / U max )× n × T 0; ⑥According to the phase difference value ( m + U a / U max )× n × T 0, calculate the voltage control voltage value to adjust the output frequency of the crystal oscillator source.

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