A mobile atomic clock timekeeping method and device

Abstract

The present invention provides a mobile atomic clock timekeeping method and device, which adds a timekeeping method strategy when the timekeeping system switches from a static state to a mobile state or from a mobile state to a static state. When the timekeeping system is in a mobile state, a cesium atomic clock is selected as the main clock. When the timekeeping system switches from a mobile state to a static state, the main clock is determined according to the performance of a hydrogen atomic clock, thereby reducing the possibility of the performance of the timekeeping system being deteriorated due to the deterioration of the stability of the hydrogen atomic clock during the movement. Compared with the prior art, the timekeeping method proposed by the present invention is applicable to a mobile timekeeping system, which solves the problem that the existing atomic clock timekeeping method is not applicable to a mobile timekeeping system. An initial operation atomic time scale calculation method using a cesium atomic clock as the main clock is added when the timekeeping system is initially operated. The cesium atomic clock is selected as the main clock, and then the 5-7 hours atomic clock time difference comparison data is used to predict the main clock rate and drive it, thereby outputting a stable time frequency signal.

Description

Technical Field

[0001] The present invention relates to the technical field of atomic clocks, and in particular to an atomic clock timekeeping method and device. Background Art

[0002] The timekeeping system is a device that outputs stable and reliable time and frequency signals in real time. With the widespread application of time and frequency signals, vehicle-mounted timekeeping systems or mobile timekeeping systems such as ships have become backups and supplements for fixed-position timekeeping systems, providing users with faster and more effective time and frequency signals.

[0003] The existing atomic clock timekeeping method is an atomic clock timekeeping method generated by a timekeeping system suitable for a fixed-position precision laboratory environment. The mobile timekeeping system in a vehicle or ship is different from the common fixed-position timekeeping system in multiple operating states, including: different atomic clock timekeeping methods in the initial operating state, stationary state and mobile state. The frequency stability of hydrogen atomic clocks is greatly affected by the ambient temperature. When switching between the mobile state and the stationary state, the frequency stability changes by an order of magnitude, and the frequency stability in the stationary state cannot be achieved within 16 hours after switching from the mobile state to the stationary state. The existing technologies are basically atomic clock timekeeping methods using hydrogen atomic clocks as the master clock. Therefore, the existing atomic clock timekeeping methods are not suitable for mobile timekeeping systems. The present invention adds a timekeeping method strategy when the timekeeping system switches from the stationary state to the mobile state or from the mobile state to the stationary state. When the timekeeping system is in the mobile state, the cesium atomic clock is selected as the master clock. When the timekeeping system switches from the mobile state to the stationary state, the master clock is determined according to the performance of the hydrogen atomic clock. This reduces the possibility that the performance of the timekeeping system will deteriorate due to the deterioration of the stability of the hydrogen atomic clock during the movement. Therefore, the timekeeping method proposed by the present invention is more suitable for mobile timekeeping systems.

[0004] In addition, the atomic time scale algorithms in the prior art are all based on the stable operation of the atomic clock and the accumulation of 3-7 days of atomic clock time difference comparison data. Therefore, the time-keeping system cannot provide a stable time and frequency signal from the time when the timekeeping system equipment is powered on to the accumulation of data for 3-7 days. Based on the characteristic that the cesium atomic clock takes less time to stabilize from the time when the power is turned on than the hydrogen atomic clock, the present invention designs an initial operation atomic time scale calculation method with the cesium atomic clock as the main clock during the initial operation of the timekeeping system. In this way, the time from the time when the timekeeping system equipment is powered on to providing a stable time and frequency signal is about 9-12 hours, which greatly shortens the time from the time when the timekeeping system equipment is powered on to outputting a stable time and frequency signal.

[0005] In summary, the existing atomic clock timekeeping methods and devices are limited to fixed-position timekeeping systems and cannot be applied to mobile timekeeping systems; at the same time, the timekeeping system in the existing atomic clock timekeeping methods takes a long time from the time the device is powered on to the time it outputs a stable time and frequency signal, and can only provide time and frequency services after 3-7 days. Therefore, it is urgent to invent a mobile atomic clock timekeeping method and device. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the present invention provides a mobile atomic clock timekeeping method and device, which is applicable to both fixed-position timekeeping systems and mobile-position timekeeping systems. It can solve the problem that the existing atomic clock timekeeping method cannot operate on the mobile-position timekeeping system, and can also solve the problem that the existing atomic clock timekeeping method cannot provide time and frequency services in a short period of time.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A method for keeping time using a mobile atomic clock includes four steps:

[0009] S1, firstly, select the initial master clock using the factory test data, determine that the cesium atomic clock has reached the nominal index according to the parameters of the cesium atomic clock, and then start to accumulate the atomic clock phase difference comparison data, use the atomic clock phase difference comparison data to reselect a cesium atomic clock as the master clock, and switch the master clock after calculating the steering amount, and then use the atomic clock time difference comparison data to calculate the weight of each cesium atomic clock, and then use the atomic clock time difference comparison data and the weight of each cesium atomic clock to calculate the initial operation atomic time scale, and use the initial operation atomic time scale to steer the master clock; the initial operation atomic time scale step of the timekeeping system shortens the time from when the timekeeping system equipment is powered on to when the timekeeping system outputs a stable time and frequency signal;

[0010] S2, after the hydrogen atomic clock reaches the nominal index, it starts to accumulate atomic clock time difference comparison data and atomic clock phase difference comparison data, and then uses the atomic clock phase difference comparison data to reselect a hydrogen atomic clock as the master clock and switch the master clock. At this time, the timekeeping system enters a static state, and then uses the atomic clock time difference comparison data to calculate the weights of each hydrogen-cesium atomic clock, and uses the atomic clock time difference comparison data and the weights of each hydrogen-cesium atomic clock to calculate the atomic time scale in the static state;

[0011] S3, when the timekeeping system switches from a static state to a mobile state, a cesium atomic clock is selected as the master clock using the atomic clock phase difference comparison data, and the master clock is switched. The weights of each hydrogen-cesium atomic clock are calculated using the atomic clock time difference comparison data, and then the atomic time scale of the mobile state is calculated using the atomic clock time difference comparison data and the weights of each hydrogen-cesium atomic clock;

[0012] S4, when the timekeeping system switches from a mobile state to a stationary state, first determine whether the hydrogen atomic clock has reached the nominal indicators based on the hydrogen atomic clock parameters. When the hydrogen atomic clock has reached the nominal indicators, use the atomic clock phase difference comparison data to select a hydrogen atomic clock as the master clock, and switch the master clock. When the hydrogen atomic clock has not reached the nominal indicators, use the atomic clock phase difference comparison data to select a cesium atomic clock as the master clock, and switch the master clock. Use the atomic clock time difference comparison data to calculate the weight of each hydrogen-cesium atomic clock, and then use the atomic clock time difference comparison data and the weights of each hydrogen-cesium atomic clock to calculate the atomic time scale.

[0013] Furthermore, the initial master clock is selected in step S1 by using the stability data of the cesium atomic clock tested at the factory, and selecting the cesium atomic clock with the smallest stability value at the specified time interval as the initial master clock.

[0014] Furthermore, in step S1 and step S2, an atomic clock is reselected as the master clock and the master clock is switched, and the stability of each atomic clock is calculated using the atomic clock phase difference comparison data, and the atomic clock with the smallest stability in a specified time interval is selected as the master clock, the steering amount is recalculated, and the master clock is switched.

[0015] Furthermore, the step of calculating the weight of each cesium atomic clock in step S1 is:

[0016] At time i-1, a quadratic or linear fitting is performed on the atomic clock time difference comparison data of a set length to obtain the predicted frequency drift and predicted rate of the atomic clock, and then the predicted value of the atomic clock time difference comparison at time i is calculated based on the predicted frequency drift and predicted rate, and then the atomic clock time difference comparison prediction data is deducted from the atomic clock time difference comparison data at time i, and the first formula is used to calculate the predicted value of the atomic clock time difference comparison at time i. The standard deviation of each atomic clock is calculated, where σ(i, j) represents the standard deviation of the jth atomic clock at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, X ij ′ represents the predicted value of the time difference comparison of the j-th atomic clock at time i, and N represents the length of the time difference comparison data of the selected j-th atomic clock;

[0017] Finally, using the second formula Calculate the weights of each atomic clock and use The maximum value of the atomic clock weight is restricted, where w1(i, j) represents the weight of the j-th atomic clock at the time i when the timekeeping system is initially running, M represents the number of atomic clocks involved in calculating the weight, and σ(i, j) represents the standard deviation of the j-th atomic clock at the time i.

[0018] Furthermore, the steps of calculating the atomic clock weight in step S2, step S3 and step S4 are:

[0019] At time i-1, the atomic time scale TA is deducted from the atomic clock time difference comparison data X of the set length to obtain TA-X, and then a first-term fitting is performed on TA-X to obtain the predicted rate V(i-1, j)′ of the atomic clock at time i-1. Then, at time i, the atomic time scale is deducted from the atomic clock time difference comparison data of the set length and a first-term fitting is performed to obtain the predicted rate V(i, j)′ of the atomic clock at time i, and then the rate change ΔV(i, j)=V(i, j)′-V(i-1, j)′ is calculated. Finally, the formula is used Calculate the weights of each atomic clock and use The maximum value of the atomic clock weight is limited, where w2(i, j) represents the weight of the j-th atomic clock at time i when it is in a stationary state, M represents the number of atomic clocks involved in calculating the weight, and ΔV(i, j) represents the rate change of the j-th atomic clock at time i;

[0020] The atomic clock weight calculation method aims to give larger weights to atomic clocks with better predictability and smaller weights to atomic clocks with poorer predictability, so that "good" atomic clocks can play a better role in atomic time scale calculations and ensure the accuracy and stability of the atomic time scale.

[0021] Furthermore, the steps for calculating the atomic time scale in steps S1, S2, S3, and S4 are:

[0022] Using the third formula Calculate the atomic time scale, where TA(i) represents the atomic time scale at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, X ij ′ represents the time difference comparison prediction value of the j-th atomic clock at time i, w(i, j) represents the weight of the j-th atomic clock at time i, and M represents the number of atomic clocks participating in the atomic time scale calculation.

[0023] Furthermore, the steps of calculating the driving amount in steps S1, S2, S3, and S4 are:

[0024] According to the fourth formula Calculate the control amount to control the master clock. Before the atomic time scale TA(i) is generated, use the fifth formula to calculate the control amount. Where s(i, j) represents the driving value of the jth atomic clock as the master clock at time i, V(i, j)′ represents the prediction rate of the master clock, τ represents the minimum time interval of the atomic clock time difference data, TA(i) represents the atomic time scale at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, and F represents the control frequency of the master clock.

[0025] The invention also provides a mobile atomic clock timekeeping device, comprising a hydrogen-cesium atomic clock group, a lossless switcher, a phase fine-tuner, a multi-channel phase comparator, a multi-channel counter and a control computer.

[0026] The 10MHz frequency signal output by the hydrogen-cesium atomic clock group is connected to the lossless switcher, the hydrogen-cesium atomic clock group generates a 10MHz frequency signal and a 1PPS pulse signal, and the lossless switcher completes the master clock switching. After one of the hydrogen-cesium atomic clocks is selected as the master clock, the lossless switcher seamlessly outputs the 10MHz frequency signal of the current master clock, that is, the seamless switching from the old master clock to the new master clock is completed;

[0027] The 10MHz frequency signal output by the lossless switch is connected to the phase fine tuner, and the phase fine tuner realizes the master clock control. After receiving the control amount, the phase fine tuner realizes the master clock control through frequency adjustment or phase adjustment;

[0028] The 10MHz signal output by the phase fine-tuner is connected to the reference channel of the multi-channel phase comparator, and the 10MHz frequency signal output by the hydrogen-cesium atomic clock group is connected to other channels of the multi-channel phase comparator except the reference channel, so as to generate phase difference comparison data of the 10MHz frequency signal of each atomic clock relative to the 10MHz frequency signal of the master clock after control, so as to provide data for optimizing the master clock; the 1PPS pulse signal output by the phase fine-tuner is connected to the reference channel of the multi-channel counter, and the 1PPS pulse signal output by the hydrogen-cesium atomic clock group is connected to other channels of the multi-channel counter except the reference channel, so as to generate time difference comparison data of the 1PPS pulse signal of each atomic clock relative to the 1PPS pulse signal of the master clock after control, so as to provide data for atomic time scale calculation.

[0029] The beneficial effects of the present invention are:

[0030] 1) Compared with the prior art, the present invention adds a timekeeping method strategy when the timekeeping system switches from a stationary state to a mobile state or from a mobile state to a stationary state. As described in steps S3 and S4, when the timekeeping system is in a mobile state, a cesium atomic clock is selected as the main clock. When the timekeeping system switches from a mobile state to a stationary state, the main clock is determined according to the performance of the hydrogen atomic clock. This is based on the fact that the frequency stability of the hydrogen atomic clock is greatly affected by the ambient temperature. As described in document [1] (Zhai Zaocheng, Analysis of the Frequency-Temperature Effect of the Hydrogen Maser Resonance Cavity, Space Measurement Technology, October 2006, Vol. 26, No. 5, P7-P11), the temperature change of the hydrogen atomic clock resonant cavity is an important factor affecting the output frequency stability of the hydrogen atomic clock. Document [2] (Sun Changbin, Li Xirui, Liu Tiexin, Digital Temperature Control Design of Hydrogen Atomic Clock, Astronomical Research and Technology, March 2023, Vol. 20, No. 2, P165-P172) points out that the international requirements for the working environment of the hydrogen atomic clock are small. When the hydrogen atomic clock is loaded on a mobile medium, the temperature control capability is difficult to reach ±0.01°C. Generally, it can be controlled within ±0.1°C, so the stability of the hydrogen atomic clock will deteriorate. Literature [3] (Li Shuaichen, Wu Jianfeng, Cui Haibo, Fang Jing, Test and Analysis of Mobile Timekeeping Performance of Domestic Hydrogen Atomic Clocks [J / OL], Journal of Navigation and Positioning, October 2022) uses experimental data to draw the conclusion that the frequency stability of the hydrogen atomic clock deteriorates by 1 order of magnitude during movement. Within 16 hours after switching from the mobile state to the stationary state, the frequency stability of the hydrogen atomic clock is between the frequency stability of the stationary state and the mobile state, and the frequency stability fluctuates greatly. Therefore, the timekeeping method of the present invention is adopted to reduce the possibility of the performance of the timekeeping system deteriorating due to the deterioration of the stability of the hydrogen atomic clock during movement. Compared with the prior art, the timekeeping method proposed by the present invention is suitable for mobile timekeeping systems, which solves the problem that the existing atomic clock timekeeping method is not suitable for mobile timekeeping systems.

[0031] 2) The present invention adds an atomic time scale calculation method for the initial operation of the timekeeping system with the cesium atomic clock as the main clock. In the prior art, the atomic time scale algorithm is based on the stable operation of the atomic clock and the accumulation of 3-7 days of atomic clock time difference comparison data. Therefore, the timekeeping system cannot provide a stable time and frequency signal from the time when the timekeeping system equipment is powered on to the accumulation of data for 3-7 days. The present invention is based on the characteristics that the cesium atomic clock takes less time from power on to stability than the hydrogen atomic clock. The cesium atomic clock takes 4-5 hours from power on to stable output signal, and the hydrogen atomic clock takes 12-72 hours. Therefore, the cesium atomic clock is first selected as the main clock, and then the 5-7 hours of atomic clock time difference comparison data is used to predict the main clock rate and control it, so as to output a stable time and frequency signal. In this way, the time from the time when the timekeeping system equipment is powered on to the output of a stable time and frequency signal is 9-12 hours, which is 3-7 days shorter than the corresponding time of the prior art, and is shortened by 27-156 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the mobile atomic clock timekeeping method;

[0033] Figure 2 It is a schematic diagram of the atomic clock timekeeping process from the initial operation to the static state of the timekeeping system;

[0034] Figure 3 It is a schematic diagram of the atomic clock timekeeping process when switching between the static state and the moving state;

[0035] Figure 4 This is a schematic diagram of the connection of the mobile atomic clock timekeeping device;

[0036] Figure 5 It is the time deviation between the 1PPS signal output in real time by the on-board timekeeping system from December 5 to December 6, 2021 and the traceable 1PPS signal. MJD represents the reduced Julian day. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0038] In this embodiment, the definition of the initial operation of the timekeeping system is: after the timekeeping system equipment is connected, from the time the equipment is powered on, until the hydrogen atomic clock in the timekeeping system reaches the nominal index and the accumulated length of the atomic clock phase difference comparison data reaches the atomic time calculation length (in this embodiment, the atomic time calculation length is 12-20 hours), the timekeeping system is in the initial operation state of the timekeeping system; the definition of the static state of the timekeeping system is: after the timekeeping system completes the initial operation stage, the timekeeping system does not move relative to the ground and remains stationary, which is called the static state; the definition of the mobile state of the timekeeping system is: when the timekeeping system moves relative to the ground, it is called the mobile state.

[0039] Embodiment 1:

[0040] like Figure 1 As shown, a method for keeping time using a mobile atomic clock according to the present invention is described, which specifically includes:

[0041] Step S1 describes the steps of the atomic clock timekeeping method for the initial operation of the timekeeping system. First, the initial master clock is selected using the factory test data. After the cesium atomic clock reaches the nominal index according to the parameters of the cesium atomic clock, the atomic clock phase difference comparison data is accumulated. The atomic clock phase difference comparison data is used to reselect a cesium atomic clock as the master clock, and the master clock is switched after calculating the steering amount. Then, the atomic clock time difference comparison data is used to calculate the weight of each cesium atomic clock. Then, the atomic clock time difference comparison data and the weight of each cesium atomic clock are used to calculate the initial operation atomic time scale, and the master clock is steered using the initial operation atomic time scale.

[0042] Step S2, after the hydrogen atomic clock reaches the nominal index, the timekeeping system enters a static state, firstly accumulates atomic clock phase difference comparison data, then uses the atomic clock phase difference comparison data to reselect a hydrogen atomic clock as the master clock, and switches the master clock, then uses the atomic clock time difference comparison data to calculate the weights of each hydrogen cesium atomic clock, and then uses the atomic clock time difference comparison data and the weights of each hydrogen cesium atomic clock to calculate the atomic time scale in the static state;

[0043] Step S3, when the timekeeping system switches from a static state to a mobile state, a cesium atomic clock is selected as the master clock using the atomic clock phase difference comparison data, and the master clock is switched, and the weights of each hydrogen cesium atomic clock are calculated using the atomic clock time difference comparison data, and then the atomic time scale of the mobile state is calculated using the atomic clock time difference comparison data and the weights of each hydrogen cesium atomic clock;

[0044] Step S4, when the timekeeping system switches from a mobile state to a stationary state, first determine whether the hydrogen atomic clock reaches the nominal index based on the hydrogen atomic clock parameters. When the hydrogen atomic clock reaches the nominal index, use the atomic clock phase difference comparison data to select a hydrogen atomic clock as the master clock, and switch the master clock. When the hydrogen atomic clock does not reach the nominal index, use the atomic clock phase difference comparison data to select a cesium atomic clock as the master clock, and switch the master clock. Use the atomic clock time difference comparison data to calculate the weight of each hydrogen cesium atomic clock, and then use the atomic clock time difference comparison data and the weight of each hydrogen cesium atomic clock to calculate the atomic time scale;

[0045] In step S1, the timekeeping system initially runs the atomic clock timekeeping method steps;

[0046] like Figure 2As shown, in this embodiment, when the timekeeping system is initially started, starting from when the atomic clock and other equipment are powered on, the cesium atomic clock needs to be powered on for more than 4 hours to reach the nominal index, and the hydrogen atomic clock needs to be powered on for more than 12 hours or 72 hours to reach the nominal index. Therefore, before the cesium atomic clock reaches the nominal index and the hydrogen atomic clock has not yet reached the nominal index, the cesium atomic clock is used as the main clock for timekeeping and outputs a stable time-frequency signal. In the prior art, it takes 3-7 days from the power-on of the atomic clock to the timekeeping system stably outputting the time-frequency signal, but it only takes 9-24 hours when the present invention is used. Therefore, the present invention shortens the time from the power-on of the atomic clock to the timekeeping system stably outputting the time-frequency signal when the timekeeping system is initially started.

[0047] The specific method is divided into the following steps:

[0048] 101, the timekeeping system is started, and the atomic clock and other equipment are powered on;

[0049] 102. Based on the stability data of the cesium atomic clock tested at the factory, the cesium atomic clock with the smallest stability value at the specified time interval is selected as the initial master clock. The purpose of selecting the initial master clock is to select a "good" clock as a reference for the atomic clock time difference comparison data and the atomic clock phase difference comparison data. Therefore, if the initial master clock selection step is missing, due to the poor performance of the reference clock, such as the stability, the atomic clock time difference comparison data and the atomic clock phase difference comparison data using the atomic clock as a reference cannot truly reflect the stability and other performance of other atomic clocks, thereby making the subsequent steps of calculating the weights of each atomic clock inaccurate.

[0050] 103. After determining that the cesium atomic clock has reached the nominal index according to the parameters of the cesium atomic clock, start accumulating the atomic clock phase difference comparison data and the atomic clock time difference comparison data for 5-20 hours;

[0051] 104. At the same time as step 103, when it is determined based on the hydrogen atomic clock parameters that the hydrogen atomic clock does not reach the nominal index or the data length does not meet the atomic time calculation requirements, the atomic clock phase difference comparison data is used to calculate the stability of each cesium atomic clock, and the atomic clock with the smallest stability at a time interval of 1 second, 1 minute or other specified time interval is selected as the new master clock; the step of selecting a new master clock using the atomic clock phase difference comparison data is performed in real time, and the purpose is to keep the "best" atomic clock as a reference in real time, so as to avoid the frequency jump or phase jump of the atomic clock used as the master clock, which affects the obtained atomic clock time difference comparison and atomic clock phase difference comparison data and also causes the frequency jump or phase jump.

[0052] Next, the steering amount is calculated. Before the atomic time scale is generated in the initial operation of the timekeeping system, the so-called steering is to deduct the accumulated frequency deviation of the master clock from the current moment to the next moment (steering frequency) from the atomic clock time difference comparison data. The specific method is: at the current moment, a linear term fitting is performed on the new master clock sequence in the 5-20 hours atomic clock time difference comparison data, and the linear term coefficient is obtained to obtain the predicted rate V(i, j)′ of the new master clock. Then, at the next moment, according to the fifth formula After calculating the control amount, the master clock is switched. At this time, the timekeeping system can output a stable time and frequency signal minus the frequency deviation of the master clock.

[0053] The purpose of this is to use the cesium atomic clock with the least stability as the main clock to output a stable time and frequency signal before the hydrogen atomic clock can no longer meet the requirements of atomic time calculation, thus shortening the time from power-on to output of a stable time and frequency signal for the timekeeping system.

[0054] 105. After the atomic clock time difference comparison data has accumulated for 20 hours, the weight of each cesium atomic clock is calculated. The purpose of calculating the atomic clock weight is to make the atomic clock with strong predictability account for a large proportion in the atomic time scale calculation. Before the atomic time scale is generated during the initial operation of the timekeeping system, the atomic clock weight is calculated based on the residual between the atomic clock time difference comparison data and the predicted value of the atomic clock time difference comparison data. This prevents the atomic clock with poor predictability from having a large weight and causing the atomic time scale to experience frequency hopping or phase hopping and other instability. The specific steps are:

[0055] At time i-1, a linear fitting is performed on the atomic clock time difference comparison data of a set length to obtain the predicted rate of the atomic clock, and then the predicted value of the atomic clock time difference comparison at time i is calculated based on the predicted rate, and then the predicted value of the atomic clock time difference comparison is deducted from the atomic clock time difference comparison data at time i, and the first formula is used to calculate the predicted value of the atomic clock time difference comparison. The standard deviation of each atomic clock is calculated, where σ(i, j) represents the standard deviation of the jth atomic clock at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, X ij ′ represents the predicted value of the time difference comparison of the jth atomic clock at time i, and N represents the length of the time difference comparison data of the selected jth atomic clock; finally, the second formula is used Calculate the weights of each atomic clock and use The maximum value of the atomic clock weight is limited, where w1(i, j) represents the weight of the j-th atomic clock at time i when the timekeeping system is initially running, M represents the number of atomic clocks involved in calculating the weight, and σ(i, j) represents the standard deviation of the j-th atomic clock at time i;

[0056] 106, calculate the initial operation atomic time scale, use the atomic clock time difference comparison data to deduct the predicted value, and prevent the atomic time scale from experiencing frequency or phase hopping instability due to changes in the atomic clock weight. The specific method is: use the third formula The atomic time scale of the initial operation of the timekeeping system is calculated, where TA1(i) represents the atomic time scale of the initial operation at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, X ij ′ represents the time difference comparison prediction value of the j-th atomic clock at time i, w1(i, j) represents the weight of the initial operation of the j-th atomic clock at time i, and M represents the number of atomic clocks participating in the atomic time scale calculation;

[0057] 107, calculate the steering amount. Different from the steering amount calculated in step 104, the timekeeping system has generated the atomic time scale at this time. The steering amount calculation is divided into two parts. First, the accumulated frequency deviation of the master clock between the current moment and the next moment (steering frequency) is deducted from the atomic clock time difference comparison data; second, the phase deviation relative to the atomic time scale TA1(i) is deducted from the atomic clock time difference comparison data. The specific method is:

[0058] According to the fourth formula Calculate the steering amount to steer the master clock, where s(i, j) represents the steering amount of the jth atomic clock as the master clock at time i, V(i, j)′ represents the master clock prediction rate, τ represents the minimum time interval of the atomic clock time difference data, which is 1-2 hours in this embodiment, TA1(i) represents the initial operating atomic time scale at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, and F represents the control frequency of the master clock, which is selected from 1 to 24 hours in this embodiment;

[0059] In this embodiment, the fourth formula controls the master clock in two parts. The first part The second part is to eliminate the accumulated frequency deviation of the master clock. The phase deviation of the master clock relative to the initial running atomic time scale TA1(i) is eliminated, and the unstable situation of frequency hopping or phase hopping of the output signal caused by frequency deviation and phase deviation is prevented.

[0060] In step S2, the atomic clock timekeeping method steps of switching the timekeeping system from the initial operation to the static state are described;

[0061] like Figure 2 As shown, 12-72 hours after the hydrogen atomic clock is powered on, it is determined based on the hydrogen atomic clock parameters that the hydrogen atomic clock has reached the nominal index and then begins to accumulate atomic clock time difference comparison data and atomic clock phase difference comparison data;

[0062] 201, after the accumulated data reaches 12-20 hours, the stability of each atomic clock is calculated using the atomic clock phase difference comparison data, and the atomic clock with the smallest stability at a time interval of 1 second, 1 minute or other specified time interval is selected as the master clock, and the steering amount is recalculated according to the step 107, and the master clock is switched;

[0063] 202, at this time, the timekeeping system enters the static state from the initial running state, and then calculates the weight of the hydrogen cesium atomic clock. The atomic clock weight calculation method is designed to give a larger weight to the atomic clock with better predictability and a smaller weight to the atomic clock with poor predictability, so that the "good" atomic clock can play a better role in the atomic time scale calculation, ensuring the accuracy and stability of the atomic time scale;

[0064] The method for calculating the weight at this time is different from the method for calculating the atomic clock weight in step 105. At this time, the timekeeping system has generated the atomic time scale. Since the atomic time scale TA is the time scale of all atomic clocks, the stability of the atomic time scale TA is better than that of the master clock. Therefore, when calculating the atomic clock weight at this time, the TA-X atomic clock time difference comparison data with the atomic time scale TA as a reference can accurately reflect the predicted rate of each atomic clock, and then the change in the predicted rate is used to calculate the weight of each atomic clock. The specific method is:

[0065] At time i-1, the atomic time scale TA is deducted from the atomic clock time difference comparison data X of the set length to obtain TA-X, and then a first-term fitting is performed on TA-X to obtain the predicted rate V(i, j)' of the atomic clock at time i-1. Then, at time i, the atomic time scale is deducted from the atomic clock time difference comparison data of the set length and a first-term fitting is performed to obtain the predicted rate V(i, j)' of the atomic clock at time i, and then the rate change ΔV(i, j)=V(i, j)'-V(i-1, j)' is calculated. Finally, the formula is used Calculate the weights of each atomic clock and use The maximum value of the atomic clock weight is limited, where w2(i, j) represents the weight of the jth atomic clock at rest at time i, M represents the number of atomic clocks involved in calculating the weight, and ΔV(i, j) represents the rate change of the jth atomic clock at time i;

[0066] 203, using the third formula Calculate the atomic time scale, where TA2(i) represents the atomic time scale at rest at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, X ij ′ represents the time difference comparison prediction value of the j-th atomic clock at time i, w2(i, j) represents the weight of the j-th atomic clock at the stationary state at time i, and M represents the number of atomic clocks participating in the atomic time scale calculation;

[0067] 204, according to the fourth formula Calculate the steering amount to steer the master clock, where s(i, j) represents the steering amount of the jth atomic clock as the master clock at time i, V(i, j)′ represents the master clock prediction rate, τ represents the minimum time interval of the atomic clock time difference data, TA2(i) represents the atomic time scale at the stationary state at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, and F represents the control frequency of the master clock, which is selected from 1 to 24 hours in this embodiment;

[0068] In this embodiment, the fourth formula controls the master clock in two parts. The first part The second part is to eliminate the accumulated frequency deviation of the master clock. The phase deviation of the master clock relative to the atomic time scale TA2(i) in the stationary state is eliminated, and the unstable situation of frequency hopping or phase hopping of the output signal due to frequency deviation and phase deviation is prevented.

[0069] Step S3 describes the steps of the atomic clock timekeeping method for switching the timekeeping system from a static state to a mobile state.

[0070] like Figure 3 As shown in the figure, we first need to select a master clock. Since hydrogen atomic clocks have high requirements for the environment, their performance is unstable when in motion. The example in the literature [3] shows that the stability of hydrogen atomic clocks deteriorates by an order of magnitude when in motion. Therefore, when the timekeeping system switches from a static state to a mobile state, a cesium atomic clock is selected as the master clock. The specific method is as follows: the stability of each cesium atomic clock is calculated using the atomic clock phase difference comparison data, and the atomic clock with the smallest stability at a time interval of 1 second, 1 minute or other specified time interval is selected as the new master clock.

[0071] 301, calculate the steering amount and switch the master clock. The steering amount calculation method is the same as 204 in step S2. Specifically, the first-order fitting is performed on the new master clock sequence in the 5-20 hours atomic clock time difference comparison data. The first-order term coefficient is obtained to obtain the new master clock prediction rate V(i, j)′, and then according to the fourth formula Calculate the steering amount to steer the master clock, where s(i, j) represents the steering amount of the jth atomic clock as the master clock at time i, V(i, j)′ represents the master clock prediction rate, τ represents the minimum time interval of the atomic clock time difference data, TA(i) represents the atomic time scale at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, and F represents the control frequency of the master clock, which is selected from 1 to 24 hours in this embodiment;

[0072] 302, calculating the atomic clock weight. The atomic clock weight method is the same as 202 in step S2. The TA-X atomic clock time difference comparison data with the atomic time scale TA as a reference is used to calculate the weight of each atomic clock. The specific method is:

[0073] At time i-1, the atomic time scale TA is deducted from the atomic clock time difference comparison data X of the set length to obtain TA-X, and then a first-term fitting is performed on TA-X to obtain the predicted rate V(i, j)′ of the atomic clock at time i-1. Then, at time i, the atomic time scale is deducted from the atomic clock time difference comparison data of the set length and a first-term fitting is performed to obtain the predicted rate V(i, j)′ of the atomic clock at time i, and then the rate change ΔV(i, j)=V(i, j)′-V(i-1, j)′ is calculated. Finally, the formula is used Calculate the weights of each atomic clock and use The maximum value of the atomic clock weight is limited, where w3((i, j) represents the weight of the j-th atomic clock in the moving state at time i, M represents the number of atomic clocks involved in calculating the weight, and ΔV(i, j) represents the rate change of the j-th atomic clock at time i;

[0074] The atomic time scale when calculating the mobile state is the same as that in step S2 203 , and the specific method is:

[0075] Using the third formula Calculate the atomic time scale, where TA3(i) represents the atomic time scale of the mobile state at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, X ij ′ represents the time difference comparison prediction value of the j-th atomic clock at time i, w3(i, j) represents the weight of the j-th atomic clock in the moving state at time i, and M represents the number of atomic clocks participating in the atomic time scale calculation;

[0076] 303, calculate the control amount, control the main clock, according to the fourth formula Calculate the steering amount to steer the master clock, where s(i, j) represents the steering amount of the jth atomic clock as the master clock at time i, V(i, j)′ represents the master clock prediction rate, τ represents the minimum time interval of the atomic clock time difference data, TA3(i) represents the atomic time scale at time i, and X ij represents the time difference comparison data of the jth atomic clock at time i, and F represents the control frequency of the master clock, which is selected from 1 to 24 hours in this embodiment;

[0077] In this embodiment, the fourth formula controls the master clock in two parts. The first part The second part is to eliminate the accumulated frequency deviation of the master clock. The phase deviation of the master clock relative to the mobile atomic time scale TA3(i) is eliminated, and the unstable situation of frequency hopping or phase hopping of the output signal due to frequency deviation and phase deviation is prevented.

[0078] Step S4 describes the steps of the atomic clock timekeeping method for switching the timekeeping system from a mobile state to a stationary state.

[0079] like Figure 3 As shown in the figure, when the timekeeping system switches from a mobile state to a stationary state, the stability of the hydrogen atomic clock will gradually improve. The experimental data in the literature [3] show that 16 hours after switching from a mobile state to a stationary state, the stability value of the hydrogen atomic clock is slightly worse than the stability data in the stationary state, but better than the stability data in the mobile state. Therefore, when the timekeeping system switches from a mobile state to a stationary state, first determine whether the hydrogen atomic clock has reached the nominal index based on the hydrogen atomic clock parameters, and then handle it in two cases. In one case, when the hydrogen atomic clock reaches the nominal index, an atomic clock is selected from the cesium atomic clock and the hydrogen atomic clock that has reached the nominal index as the master clock. The specific method is: use the atomic clock phase difference comparison data to calculate the stability of each hydrogen cesium atomic clock, and select the time interval as 1 second, 1 minute or other specified time. The atomic clock with the smallest stability at the interval is selected as the new master clock; then the control amount is calculated and the master clock is switched according to step 301, the weight of each atomic clock is calculated according to step 302, the atomic time scale is calculated, and the control amount is recalculated according to step 303 to control the master clock; in the second case, when the hydrogen atomic clock does not reach the nominal index, the same as step S3, first a cesium atomic clock is selected as the master clock, and the specific method is: the stability of each cesium atomic clock is calculated by using the atomic clock phase difference comparison data, and the atomic clock with the smallest stability at a time interval of 1 second, 1 minute or other specified time interval is selected as the new master clock; then the control amount is calculated and the master clock is switched according to step 301, the weight of each atomic clock is calculated according to step 302, the atomic time scale is calculated, and the control amount is recalculated according to step 303 to control the master clock;

[0080] In this embodiment, the atomic clock prediction rate method and the atomic clock time difference comparison prediction value calculation method can also be completed by other methods;

[0081] Embodiment 2:

[0082] like Figure 4 As shown, based on Example 1, the present invention also discloses a mobile atomic clock timekeeping device, including: a hydrogen cesium atomic clock group 401, a lossless switch 402, a phase fine-tuner 403, a multi-channel phase comparator 404, a multi-channel counter 405, and a control processing computer 406.

[0083] The hydrogen cesium atomic clock group 401 is used to generate a 10 MHz frequency signal and a 1PPS pulse signal;

[0084] The lossless switch 402 is used to complete the master clock switching. After one of the hydrogen-cesium atomic clocks is selected as the master clock, the lossless switch can switch to output the 10MHz frequency signal of the current master clock, that is, the seamless switching from the old master clock to the new master clock is completed;

[0085] The phase fine tuner 403 is used to realize the master clock control. After receiving the control amount, the phase fine tuner realizes the master clock control through frequency adjustment or phase adjustment;

[0086] The multi-channel phase comparator 404 is used for comparing 10 MHz frequency signals to generate atomic clock phase difference comparison data;

[0087] The multi-channel counter 405 is used for comparing 1PPS pulse signals to generate atomic clock time difference comparison data;

[0088] The control processing computer 406 is used to perform the data processing in Example 1, including atomic clock weight calculation, atomic time scale calculation, steering amount calculation, etc., and is also used to send a master clock switching instruction to the lossless switch 402 and send a steering amount to the phase fine tuner 403;

[0089] When the timekeeping system is connected, the 10MHz frequency signal output by the hydrogen cesium atomic clock in the hydrogen cesium atomic clock group 401 is connected to the lossless switch 402. When receiving the master clock switching instruction, the lossless switch 402 outputs the switched master clock 10MHz frequency signal; the 10MHz frequency signal output by the lossless switch 402 is connected to the phase fine tuner 403. After receiving the control amount, the phase fine tuner controls the master clock, and then outputs the controlled 10MHz frequency signal and 1PPS pulse signal;

[0090] The 10MHz signal output by the phase fine-tuner 403 is connected to the reference channel of the multi-channel phase comparator 404, and the 10MHz frequency signal output by the hydrogen-cesium atomic clock group 401 is connected to other channels of the multi-channel phase comparator 404 except the reference channel to generate atomic clock phase difference comparison data; the 1PPS pulse signal output by the phase fine-tuner 403 is connected to the reference channel of the multi-channel counter 405, and the 1PPS pulse signal output by the hydrogen-cesium atomic clock group 401 is connected to other channels of the multi-channel counter 405 except the reference channel.

[0091] Example 3

[0092] Connect the equipment according to Example 2, build a timekeeping system, select 2 hydrogen atomic clocks and 3 cesium atomic clocks to form a hydrogen cesium atomic clock group, and use the atomic clock timekeeping method steps described in Example 1. From the time the timekeeping system is powered on, use step S1 to perform the initial operation of the atomic clock timekeeping of the timekeeping system. After 8 hours, the timekeeping system can output a stable time and frequency signal. Then use step S2 to switch the timekeeping system from the initial operation to the atomic clock timekeeping in the static state. In the static state, the frequency stability of the timekeeping system clock group reaches 2.14E-15 / 10000s. 1.77E-15 / 1d; Step S3 is used to switch the timekeeping system from a stationary state to a mobile state atomic clock timekeeping. After the timekeeping system is transported on a secondary road for 8 hours, step S4 is used to switch the timekeeping system from a mobile state to a stationary state atomic clock timekeeping. Before the on-board transportation, the time difference between the 1PPS signal output by the timekeeping system and the traceable 1PPS signal is 0.28ns. After 8 hours of on-board transportation, the time difference between the 1PPS signal output by the timekeeping system and the traceable 1PPS signal is 25.5ns, and the difference between the two is better than 26ns. Figure 5 Shown is the time deviation between the 1PPS signal output in real time by the on-board timekeeping system from December 5 to December 6, 2021 and the traceable 1PPS signal.

[0093] In this embodiment, Example 2 provides support for Example 1, the atomic clock phase difference comparison data and atomic clock time difference comparison data used in Example 1 are generated by the device of Example 2, the master clock control described in Example 1 is achieved by the phase fine-tuner 403 described in Example 2, and the master clock switching described in Example 1 is achieved by the lossless switcher 402 described in Example 2. Example 3 is a mobile timekeeping system implemented according to the method of Example 1 and using the device connection method of Example 2.

[0094] In summary, the embodiments of the present invention provide a method and device for keeping time using a mobile atomic clock, which have the following beneficial effects compared with the prior art:

[0095] (1) A timekeeping method strategy is added when the timekeeping system switches from a stationary state to a mobile state or from a mobile state to a stationary state. When the timekeeping system is in a mobile state, a cesium atomic clock is selected as the master clock. When the timekeeping system switches from a mobile state to a stationary state, the master clock is determined according to the performance of the hydrogen atomic clock. This reduces the possibility that the performance of the timekeeping system will deteriorate due to the deterioration of the stability of the hydrogen atomic clock during the movement. Therefore, the timekeeping method proposed in the present invention has a wider application range, not only applicable to timekeeping systems with fixed positions, but also applicable to timekeeping systems with mobile positions, solving the problem of limited application scope of the existing atomic clock timekeeping methods;

[0096] (2) Based on the characteristic that the time taken by the cesium atomic clock to stabilize after power-on is shorter than that of the hydrogen atomic clock, the present invention designs an atomic time scale calculation method for the initial operation of the timekeeping system with the cesium atomic clock as the main clock during the initial operation. In this way, the time from when the timekeeping system equipment is powered on to providing a stable time and frequency signal is about 9-12 hours, which solves the limitation of the prior art that the timekeeping system takes a long time from when the equipment is powered on to output a stable time and frequency signal, and can only provide time and frequency services after 3-7 days.

[0097] Those skilled in the art will appreciate that the foregoing are merely preferred embodiments of the invention and do not limit the invention. Although the invention has been described in detail with reference to the aforementioned examples, those skilled in the art can still modify the technical solutions described in the aforementioned examples or make equivalent substitutions for some of the technical features therein. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included in the scope of protection of the invention.

Claims

1. A mobile atomic clock timekeeping method, characterized in that The steps include: S1, firstly, select the initial master clock using the factory test data, determine that the cesium atomic clock has reached the nominal index according to the parameters of the cesium atomic clock, and then start to accumulate the atomic clock phase difference comparison data, use the atomic clock phase difference comparison data to reselect a cesium atomic clock as the master clock, and switch the master clock after calculating the steering amount, and then use the atomic clock time difference comparison data to calculate the weight of each cesium atomic clock, and then use the atomic clock time difference comparison data and the weight of each cesium atomic clock to calculate the initial operation atomic time scale, and use the initial operation atomic time scale to steer the master clock; the initial operation atomic time scale step of the timekeeping system shortens the time from when the timekeeping system equipment is powered on to when the timekeeping system outputs a stable time and frequency signal; S2, after the hydrogen atomic clock reaches the nominal index, it starts to accumulate atomic clock time difference comparison data and atomic clock phase difference comparison data, and then uses the atomic clock phase difference comparison data to reselect a hydrogen atomic clock as the master clock and switch the master clock. At this time, the timekeeping system enters a static state, and then uses the atomic clock time difference comparison data to calculate the weights of each hydrogen-cesium atomic clock, and uses the atomic clock time difference comparison data and the weights of each hydrogen-cesium atomic clock to calculate the atomic time scale in the static state; S3, when the timekeeping system switches from a static state to a mobile state, a cesium atomic clock is selected as the master clock using the atomic clock phase difference comparison data, and the master clock is switched. The weights of each hydrogen-cesium atomic clock are calculated using the atomic clock time difference comparison data, and then the atomic time scale of the mobile state is calculated using the atomic clock time difference comparison data and the weights of each hydrogen-cesium atomic clock; S4, when the timekeeping system switches from a mobile state to a stationary state, first determine whether the hydrogen atomic clock has reached the nominal indicators based on the hydrogen atomic clock parameters. When the hydrogen atomic clock has reached the nominal indicators, use the atomic clock phase difference comparison data to select a hydrogen atomic clock as the master clock, and switch the master clock. When the hydrogen atomic clock has not reached the nominal indicators, use the atomic clock phase difference comparison data to select a cesium atomic clock as the master clock, and switch the master clock. Use the atomic clock time difference comparison data to calculate the weight of each hydrogen-cesium atomic clock, and then use the atomic clock time difference comparison data and the weights of each hydrogen-cesium atomic clock to calculate the atomic time scale.

2. The mobile atomic clock timekeeping method according to claim 1, characterized in that: In step S1, the initial master clock is selected by using the stability data of the cesium atomic clock tested at the factory, and selecting the cesium atomic clock with the smallest stability value at a specified time interval as the initial master clock.

3. The mobile atomic clock timekeeping method according to claim 1, characterized in that: In step S1 and step S2, an atomic clock is reselected as the master clock and the master clock is switched. The stability of each atomic clock is calculated using the atomic clock phase difference comparison data, and the atomic clock with the smallest stability in a specified time interval is selected as the master clock, the steering amount is recalculated, and the master clock is switched.

4. The mobile atomic clock timekeeping method according to claim 1, characterized in that: The steps for calculating the weight of each cesium atomic clock in step S1 are: At time i-1, a quadratic or linear fitting is performed on the atomic clock time difference comparison data of a set length to obtain the predicted frequency drift and predicted rate of the atomic clock, and then the predicted value of the atomic clock time difference comparison at time i is calculated based on the predicted frequency drift and predicted rate, and then the atomic clock time difference comparison prediction data is deducted from the atomic clock time difference comparison data at time i, and the first formula is used to calculate the predicted value of the atomic clock time difference comparison at time i. The standard deviation of each atomic clock is calculated, where represents the standard deviation of the jth atomic clock at time i, represents the time difference comparison data of the jth atomic clock at time i, represents the predicted value of the time difference comparison of the j-th atomic clock at time i, and N represents the length of the time difference comparison data of the selected j-th atomic clock; Finally, using the second formula , calculate the weights of each atomic clock, and use The maximum value of the atomic clock weight is limited, where represents the weight of the jth atomic clock at time i during the initial operation of the timekeeping system, M represents the number of atomic clocks involved in calculating the weight, Represents the standard deviation of the jth atomic clock at the i-th moment.

5. The mobile atomic clock timekeeping method according to claim 1, characterized in that: The steps of calculating the atomic clock weight in step S2, step S3 and step S4 are: Compare the atomic clock time difference of the set length at time i-1 Subtract atomic time scale After getting , then Perform a linear fit to obtain the predicted rate of the atomic clock at time i-1 Then, at time i, the atomic clock time difference comparison data of the set length is deducted from the atomic time scale and a linear fitting is performed to obtain the predicted rate of the atomic clock at time i. , and then calculate the rate change , and finally use the formula Calculate the weights of each atomic clock and use The maximum value of the atomic clock weight is limited, where represents the weight of the jth atomic clock at rest at time i, M represents the number of atomic clocks involved in calculating the weight, represents the rate change of the jth atomic clock at the time i; The atomic clock weight calculation method aims to give larger weights to atomic clocks with better predictability and smaller weights to atomic clocks with poorer predictability, so that "good" atomic clocks can play a better role in atomic time scale calculations and ensure the accuracy and stability of the atomic time scale.

6. The mobile atomic clock timekeeping method according to claim 1, characterized in that: The steps for calculating the atomic time scale in steps S1, S2, S3, and S4 are: Using the third formula Calculate the atomic time scale, where represents the atomic time scale at time i, represents the time difference comparison data of the jth atomic clock at time i, represents the time difference comparison prediction value of the jth atomic clock at time i, represents the weight of the jth atomic clock at time i, and M represents the number of atomic clocks participating in the atomic time scale calculation.

7. The mobile atomic clock timekeeping method according to claim 1, characterized in that: The steps of calculating the driving amount in steps S1, S2, S3, and S4 are: According to the fourth formula The master clock is controlled by calculating the control quantity. Before it is generated, the fifth formula is used to calculate the driving amount ,in, represents the driving amount of the jth atomic clock as the master clock at time i, represents the master clock forecast rate, The minimum time interval representing the atomic clock time difference data, represents the atomic time scale at time i, represents the time difference comparison data of the jth atomic clock at time i, Indicates the master clock control frequency.

8. A mobile atomic clock timekeeping device using the method according to any one of claims 1 to 7, comprising a hydrogen-cesium atomic clock group, a lossless switcher, a phase fine-tuner, a multi-channel phase comparator, a multi-channel counter and a control computer, characterized in that: The 10MHz frequency signal output by the hydrogen-cesium atomic clock group is connected to the lossless switcher, the hydrogen-cesium atomic clock group generates a 10MHz frequency signal and a 1PPS pulse signal, and the lossless switcher completes the master clock switching. After one of the hydrogen-cesium atomic clocks is selected as the master clock, the lossless switcher seamlessly outputs the 10MHz frequency signal of the current master clock, that is, the seamless switching from the old master clock to the new master clock is completed; The 10MHz frequency signal output by the lossless switch is connected to the phase fine tuner, and the phase fine tuner realizes the master clock control. After receiving the control amount, the phase fine tuner realizes the master clock control through frequency adjustment or phase adjustment; The 10MHz signal output by the phase fine-tuner is connected to the reference channel of the multi-channel phase comparator, and the 10MHz frequency signal output by the hydrogen-cesium atomic clock group is connected to other channels of the multi-channel phase comparator except the reference channel, so as to generate phase difference comparison data of the 10MHz frequency signal of each atomic clock relative to the 10MHz frequency signal of the master clock after control, and provide data for the master clock time; the 1PPS pulse signal output by the phase fine-tuner is connected to the reference channel of the multi-channel counter, and the 1PPS pulse signal output by the hydrogen-cesium atomic clock group is connected to other channels of the multi-channel counter except the reference channel, so as to generate time difference comparison data of the 1PPS pulse signal of each atomic clock relative to the 1PPS pulse signal of the master clock after control, and provide data for atomic time scale calculation.

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