High-precision time-keeping low-phase-noise time synchronization equipment

Abstract

The invention provides a high-precision time-keeping low-phase-noise time synchronization device, and belongs to the technical field of time synchronization. The system comprises a power supply module, a satellite time service module, a frequency source module, a clock synchronization module, a frequency shunt module, a communication interface module and a Bluetooth module. Wherein the power supply module adopts a dual-power-supply redundant circuit design, and after one power supply breaks down, the other power supply can be automatically switched; the satellite time service module adopts a single Beidou signal baseband signal processing algorithm and an anti-cheating design, so that the safety of equipment is improved; the frequency source module comprises a constant-temperature crystal oscillator and a rubidium atomic clock, and high-time-keeping and low-phase-noise signal output is achieved in the mode that the crystal oscillator and the atomic clock are complementary. According to the invention, the problem that the conventional time synchronization equipment cannot have high time keeping precision and low phase noise of output signals at the same time is solved, a high-steady-state low-phase-noise 10MHz frequency standard signal, a 1PPS time service signal and an NTP network time service signal can be provided, and time service is provided for various terminals or servers.

Description

Technical Field

[0001] This invention relates to the field of time synchronization technology, specifically to a high-precision, low-phase-noise time synchronization device. Background Technology

[0002] High-precision time synchronization is crucial in many fields, including modern communications, power, finance, and scientific research. For example, in 5G communication base stations, precise time synchronization between base stations is required to ensure accurate signal transmission and reception; even slight time deviations can lead to signal interference and degraded communication quality. In wide-area protection and control of power systems, the time synchronization accuracy between equipment in various substations affects the accuracy of fault diagnosis and handling. If time is not synchronized, misjudgments may occur, potentially causing large-scale power outages.

[0003] Existing time synchronization equipment has certain limitations in terms of timekeeping performance and output frequency signal phase noise. The equipment uses ordinary crystal oscillators or atomic clocks as frequency sources. Ordinary crystal oscillators have the characteristics of high short-term frequency stability and low output signal phase noise, but their long-term frequency stability and timekeeping performance are poor; atomic clocks have the characteristics of high long-term frequency stability and timekeeping performance, but their short-term stability is low and their output signal phase noise is poor.

[0004] If the time synchronization device's accuracy rapidly declines, it will be unable to meet the system's continuous demand for high-precision time over a short period. Simultaneously, phase noise is also a significant issue; high phase noise affects signal quality and reduces the system's anti-interference capability. Therefore, developing a time synchronization device that provides high-precision timekeeping with low phase noise characteristics is of great practical importance. Summary of the Invention

[0005] The purpose of this invention is to provide a high-precision, low-phase-noise time synchronization device to solve the problem mentioned in the background art that existing time synchronization devices cannot simultaneously achieve high timekeeping accuracy and low phase noise in the output signal.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A high-precision, low-phase-noise time synchronization device includes a power management unit, a single BeiDou satellite timing module, a frequency source module, a time synchronization module, and a frequency splitter module;

[0008] The power management unit uses a dual-switching power supply circuit to achieve dual power backup. When one power supply fails, it automatically switches to the other power supply.

[0009] The single BeiDou satellite timing module is used to process satellite signals and output BeiDou satellite timing signals;

[0010] The frequency source module comprises a constant temperature crystal oscillator and a rubidium atomic clock; during the time service stage, the constant temperature crystal oscillator and the rubidium atomic clock are simultaneously synchronized to the Beidou satellite time service signal output by the single Beidou satellite time service module, so as to complete clock taming; after entering the time keeping stage, the constant temperature crystal oscillator is automatically switched from synchronization to the Beidou satellite time service signal to synchronization to the signal of the tamed rubidium atomic clock;

[0011] The time synchronization module comprises a microprocessor and a time synchronization chip; during the process of taming the constant temperature crystal oscillator and the rubidium atomic clock, the time synchronization chip constantly collects the frequency data of the rubidium atomic clock, and adjusts the frequency control word of the rubidium atomic clock and the constant temperature crystal oscillator in real time through a PID control algorithm, so as to complete the taming of the constant temperature crystal oscillator and the rubidium atomic clock; the frequency control word data in the taming process is used to analyze the drift characteristics of the rubidium atomic clock, to construct an aging model curve, and to store the aging model curve in the on-board Flash memory; when the satellite signal is lost, the microprocessor adjusts the frequency of the rubidium atomic clock according to the stored aging model curve, so as to realize high-precision time keeping of the rubidium atomic clock;

[0012] The frequency distribution module distributes the high-precision time signal and the frequency signal output by the frequency source module according to different protocols and interface requirements.

[0013] Further, the time synchronization device further comprises a display control unit, a communication interface module and a Bluetooth module;

[0014] The display control unit displays and monitors the device state data through the cooperation of the keys and the display screen, and sends control instructions to the device through the key operation, so as to set the working parameters of the device;

[0015] The communication interface module communicates with the display control unit through the RS232 interface, and transmits data between the display control unit, the single Beidou satellite time service module, the time synchronization module and the Bluetooth module;

[0016] The Bluetooth module communicates with the communication interface module through the serial port, so as to realize the Bluetooth remote control of the device and the remote monitoring of the device state.

[0017] Further, in the time synchronization module, the specific way of constructing the aging model curve is as follows:

[0018] After receiving the Beidou time service signal and tracking and locking, the phase comparator is used to collect the phase difference between the 1pps signal generated by the rubidium atomic clock and the reference 1pps signal, and the sampling window is 1000 points;

[0019] The sampling data is processed by the first-order Kalman filtering algorithm and the 3σ mean value algorithm, so as to eliminate abnormal values and random noise;

[0020] The processed data is subjected to secondary model curve fitting, and the fitting formula is as follows:

[0021]

[0022] wherein, / is the mean value of 1000 sampling data, 、 、 is the fitting coefficient.

[0023] Further, the lengths of the lines for distributing signals in the frequency distribution module are equal, and the specific working mode of the frequency distribution module is:

[0024] The 1PPS signal is output through an LVTTL level interface, and the 10MHz frequency signal is output through a 50Ω SMA interface.

[0025] The signals are distributed by the shunt driving chip, and the phase consistency between the output signals is ensured to be within 1ns.

[0026] Compared with the prior art, the beneficial effects of the present application are:

[0027] 1. High-precision time synchronization: By combining a single Beidou satellite time module with a high-stability rubidium atomic clock and a constant-temperature crystal oscillator, and using an advanced time synchronization processing algorithm, a time synchronization precision better than 10ns (RMS) is achieved, which can meet the needs of the fields of communication, power, finance and other fields with extremely high requirements for time synchronization precision.

[0028] 2. Excellent time keeping ability: When the satellite signal loses lock or becomes unusable, the device can automatically lock the crystal oscillator frequency to the rubidium clock for time keeping. By relying on the high time keeping characteristics of the rubidium clock and the intelligent learning algorithm for fine tuning of the rubidium clock, long-term high-precision time keeping can be maintained, with a time keeping precision better than 500ns / day, ensuring that the system can still operate stably in the case of interruption of external time signals.

[0029] 3. Low phase noise characteristics: The use of a constant-temperature crystal oscillator and the cooperative work of the frequency source module and the time synchronization module effectively reduce the phase noise of the output signal, with a phase noise index better than -140dBc / Hz @10Hz, improving the signal quality and the anti-interference ability of the system.

[0030] 4. Rich interface and protocol support: Supports multiple time signal output interfaces and communication protocols, and can flexibly adapt to different application scenarios and external devices, with wide applicability. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is the structure block diagram of a high-precision time keeping low phase noise time synchronization device in the embodiment of the present application. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0033] A high-precision time-keeping low-phase-noise time synchronization device, as shown in Figure 1 includes a display control unit, a power management unit, a single Beidou satellite time service module, a frequency source module, a time synchronization module, a frequency distribution module, a communication interface module and a Bluetooth module.

[0034] The power management unit adopts a high-efficiency double-switch power supply circuit to convert the external input AC 220V power into stable DC 12V power. The 12V input double power supply design circuit realizes double power supply backup. When a problem occurs in a power supply, the circuit will automatically switch to another power supply to provide stability for the device operation and provide the required operating voltage for each module. For example, 5V voltage is provided for the single Beidou satellite time service module, 3.3V and 5V different voltages are provided for the frequency source module, and 3.3V and 5V different voltages are provided for the communication interface module to ensure stable operation of each module.

[0035] The single Beidou satellite time service module selects a single Beidou receiver chip with high performance, such as the ATGM336H-6N-22 model chip of Zhongke Microelectronics. The chip can simultaneously track multiple Beidou satellites and solve satellite signals through the built-in algorithm. In actual application scenarios, such as in an environment with many high-rise buildings in the city, although part of the satellite signals may be blocked, the module can still stably obtain high-precision time information due to its strong anti-interference ability and multi-satellite receiving characteristics, and the time service accuracy can reach 10ns (RMS).

[0036] The frequency source module is composed of a constant temperature crystal oscillator and a rubidium atomic clock. The rubidium clock has the characteristics of good long-term stability and poor short-term stability. In the time service stage, the internal crystal oscillator and the rubidium clock are simultaneously synchronized to the Beidou satellite time service signal output by the satellite time service module. After the clock taming is completed, the average frequency accuracy of the rubidium clock can reach 1E-13. After entering the time-keeping stage, the internal crystal oscillator automatically changes from synchronization to the Beidou satellite time service signal to synchronization to the high-frequency accuracy rubidium clock signal after taming. By using the characteristics of good long-term stability and low aging rate of the rubidium clock, the time-keeping accuracy of the internal crystal oscillator can be improved from 10us / day to a high time-keeping accuracy of 500ns / day. The constant temperature crystal oscillator has the characteristics of good short-term stability and can provide a low-phase-noise 10MHz frequency reference signal for the device to ensure the stability of the frequency signal. The phase noise at 10Hz can reach -145dBc / Hz.

[0037] The time synchronization module adopts a high-performance microprocessor GD32F407RET6 and a dedicated time synchronization chip MS1022. In the process of taming the crystal oscillator and rubidium clock, the time synchronization chip continuously collects the frequency data of the rubidium clock, adjusts the frequency control word of the rubidium clock and the crystal oscillator in real time through the PID control algorithm, to complete the taming of the crystal oscillator and the rubidium clock. Through the frequency control word data in the taming process, the drift characteristics of the rubidium clock are analyzed, an aging model is constructed, and the aging model of the rubidium clock is stored in the on-board Flash memory. When the satellite signal is lost, the microprocessor adjusts the frequency of the rubidium clock according to the stored rubidium clock aging model curve, so as to realize high-precision time keeping, and the constant-temperature crystal oscillator is synchronized with the rubidium clock, ensuring the high time keeping accuracy of the crystal oscillator. For example, in a test of simulating satellite signal interruption, the time keeping accuracy of the device within 24 hours is maintained within 500ns.

[0038] The frequency distribution module selects a chip GC26E31S / P with high-precision signal distribution capability, which can distribute the high-precision time signal and frequency signal output by the frequency source according to different protocols and interface requirements. For example, the 1PPS signal is output through the LVTTL level interface, and the 10MHz frequency signal is output through the 50Ω SMA interface. In the signal distribution process, through equal-length processing of the signal lines inside the frequency distribution module and using the high-performance distribution driving chip GC26E31S / P, the phase consistency between the output signals can be guaranteed within 1ns.

[0039] The RS232 interface in the communication interface module communicates with the display and control unit, displays and monitors the device state data through the cooperation of the keys and the display screen, sends control instructions to the device through key operation, and sets the working parameters such as clock taming parameters, antenna feeder delay, time reference source, and network communication parameters. Adjusting the clock taming parameters can effectively adjust the clock taming speed of the time synchronization module and the accuracy of the output time signal to meet the needs of different application scenarios. Adjusting the antenna feeder delay can eliminate the signal transmission delay caused by the cable length of the single Beidou satellite time service module receiving satellite signals. Through the setting of the time reference source, the real-time locking of the frequency source module to different time reference sources can be adjusted. Through the setting of the communication parameters of the Bluetooth communication module, the communication distance and bandwidth of the Bluetooth communication can be adjusted to meet the needs of different communication scenarios. The communication interface module can collect device working state information in real time, send data to the Bluetooth module through the TTL serial port, receive control instructions sent by the Bluetooth module, and realize remote control of the device.

[0040] The Bluetooth module communicates with the communication interface module through the serial port to realize the functions of Bluetooth remote control of the device and device state monitoring.

[0041] The power supply control unit of the application adopts a double power supply circuit design, the equipment uses the first power supply module to provide power supply for each module by default, when the first power supply module fails, the power supply control unit automatically uses the second power supply module as the power supply of the equipment, ensuring the stability of the equipment work.

[0042] The frequency source of the equipment of the application adopts a combination of constant temperature crystal oscillator and rubidium clock, which has the characteristics of good short-term stability of constant temperature crystal oscillator and good long-term stability of rubidium clock, that is, it can output a low phase noise frequency standard signal through the constant temperature crystal oscillator, and the phase noise index is better than-140dBc / Hz @10Hz, and it can also use the rubidium clock to maintain high time keeping performance index, and the time keeping accuracy is better than 500ns / day.

[0043] The single-beidou satellite time service module of the application is authenticated by single-beidou, only solves the Beidou time service navigation signal inside, can prevent GPS signal deception and strong anti-interference, and increases the safety and stability of the equipment operation.

[0044] In addition, the device is built-in Bluetooth communication module, cooperate with remote Bluetooth communication equipment, can realize time synchronization equipment work parameter setting and state real-time monitoring, friendly man-machine interaction, increase the operation of the device.

[0045] In summary, the application realizes a high-precision time keeping low phase noise time synchronization device, solves the problem that the previous time synchronization device cannot have high time keeping accuracy and low phase noise output signal at the same time. The time synchronization device can be designed with a standard case, so it can be installed in an indoor standard shelf. The application can provide high-stable low phase noise 10MHz frequency standard signal, 1PPS time service signal and NTP network time service signal, and provide time service for various terminals or servers.

[0046] Although embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the foregoing embodiments, since many variations, modifications, substitutions and changes can be made to these embodiments without departing from the spirit and the scope of the application as defined in the appended claims and their equivalents.

Claims

1. A high-precision, low-phase-noise time synchronization device, characterized in that, It includes a power management unit, a single BeiDou satellite timing module, a frequency source module, a time synchronization module, and a frequency splitter module; The power management unit uses a dual-switching power supply circuit to achieve dual power backup. When one power supply fails, it automatically switches to the other power supply. The single BeiDou satellite timing module is used to process satellite signals and output BeiDou satellite timing signals; The frequency source module includes a temperature-controlled crystal oscillator and a rubidium atomic clock. During the timing phase, the temperature-controlled crystal oscillator and the rubidium atomic clock are simultaneously synchronized with the BeiDou satellite timing signal output by the single BeiDou satellite timing module to complete clock discipline. After entering the timekeeping phase, the temperature-controlled crystal oscillator automatically switches from being synchronized with the BeiDou satellite timing signal to being synchronized with the disciplined rubidium atomic clock signal. The time synchronization module includes a microprocessor and a time synchronization chip. During the process of taming the cryogenic crystal oscillator and the rubidium atomic clock, the time synchronization chip continuously collects the frequency data of the rubidium atomic clock and adjusts the frequency control words of the rubidium atomic clock and the cryogenic crystal oscillator in real time through a PID control algorithm to complete the taming of the cryogenic crystal oscillator and the rubidium atomic clock. Using the frequency control word data during the taming process, the drift characteristics of the rubidium atomic clock are analyzed to construct an aging model curve, which is then stored in the onboard Flash memory. When the satellite signal is lost, the microprocessor fine-tunes the frequency of the rubidium atomic clock according to the stored aging model curve to achieve high-precision timekeeping of the rubidium atomic clock. The frequency splitter module distributes the high-precision time and frequency signals output from the frequency source module according to different protocols and interface requirements.

2. The high-precision, low-phase-noise time synchronization device according to claim 1, characterized in that, It also includes a display and control unit, a communication interface module, and a Bluetooth module; The display and control unit displays and monitors equipment status data through the combination of buttons and a display screen, and sends control commands to the equipment through button operation to set the equipment's operating parameters; The communication interface module communicates with the display and control unit via an RS232 interface, and transmits data between the display and control unit and the single Beidou satellite timing module, time synchronization module, and Bluetooth module; The Bluetooth module communicates with the communication interface module via a serial port to enable remote Bluetooth control and remote monitoring of the device's status.

3. The high-precision, low-phase-noise time synchronization device according to claim 1, characterized in that, In the time synchronization module, the specific method for constructing the aging model curve is as follows: After receiving the BeiDou timing signal and tracking and locking, a phase comparator is used to collect the phase difference between the 1pps signal generated by the rubidium atomic clock and the reference 1pps signal, with a sampling window of 1000 points; The sampled data are processed using a first-order Kalman filter and a 3σ mean algorithm to remove outliers and random noise. The processed data is then subjected to quadratic model curve fitting, and the fitting formula is as follows: in, / The mean of 1000 sampled data points. , , represents the fitting coefficient.

4. The high-precision, low-phase-noise time synchronization device according to claim 1, characterized in that, In the frequency splitter module, the lines used for signal distribution are of equal length. The specific working principle of the frequency splitter module is as follows: Output a 1PPS signal through an LVTTL level interface and output a 10MHz frequency signal through a 50Ω SMA interface; By using a splitter driver chip to distribute the signals, the phase consistency between each output signal is ensured to be within 1ns.

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