Decentralized four-dimensional spatiotemporal reference unification method and timekeeping apparatus

Abstract

The present application relates to a decentralized four-dimensional spatiotemporal reference unification method and a timekeeping apparatus. The method comprises: providing at least three timekeeping apparatuses at different positions in a coordinate system, respectively; performing local measurement of proper times by means of the timekeeping apparatuses, and converting the proper times into origin coordinate times; generating a plurality of clock offset data tables by periodically performing a pairwise comparison of the origin coordinate times; performing transformation coefficient verification and transformation coefficient ephemeris adjustment according to the clock offset data tables; performing deviation verification and deviation ephemeris adjustment according to a most recent clock offset data table, and achieving four-dimensional spatiotemporal reference unification on the basis of a four-dimensional spatiotemporal simultaneity condition; and according to the ephemerides and locally measured proper times for achieving four-dimensional spatiotemporal reference unification, converting the proper times into broadcast coordinate times, and using a broadcast timestamp to deliver timing to other timing users. The present application establishes, within an individual barycentric coordinate system, a time unification method with long-term stability and traceability to the definition of the SI second.

Description

A decentralized four-dimensional spatiotemporal benchmark unification method and timekeeping device

[0001] This application claims priority to Chinese Patent Application No. 202510353205.6, filed on March 25, 2025, entitled “A Decentralized Four-Dimensional Spatiotemporal Reference Unification Method and Timekeeping Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of time measurement technology, and in particular to a decentralized four-dimensional spatiotemporal reference unification method and timekeeping device. Background Technology

[0003] The China Association for Science and Technology's 2021 major scientific question, "Is there a unified time system beyond Earth?", is a groundbreaking scientific question. For future lunar bases, Mars bases, Jupiter's moons, Saturn's moons, asteroids, and deep space missions, a unified time is a common language for all humanity and a cornerstone of science, technology, and engineering. The relativistic effect of clocks running slow while weak gravitational potential clocks run fast has a significant impact on atomic clocks. The "timekeeping-time dissemination" rule based on Earth's standard time is not applicable to vast areas far from Earth. How to unify time remains a shared challenge in the fields of astronomy, metrology, space science, and technology.

[0004] Currently, common studies, such as those proposed by American scholars Kopeikin and Kaplan (Lunar time in general relativity, Phy Rev, 110(8):084047, Oct. 2024) and Ashby and Patla (A relativistic framework to estimate clock rates on the Moon, The Astronomical Journal, 168:112 (14pp), 2024 September), only focus on the differences between the Earth and the Moon, and do not provide a solution to the problem of how to unify the time among multiple timekeeping devices located in different locations.

[0005] Other methods, such as the method and spatial timekeeping system for unifying time in a wide area provided by Chinese patent ZL2020106073336, and the method and time user system based on pulsar sequence rules provided by Chinese patent ZL202210482311.0, address the problem of time unification between multiple local areas spanning different coordinate systems. However, they do not provide a solution for how to unify time between timekeeping devices in a separate centroid coordinate system.

[0006] The timekeeping system on Earth is centralized, centered around the International Bureau of Weights and Measures (BIPM) Time and Frequency Measurement Laboratory, which calculates TAI and publishes UTC. However, the Earth-based timekeeping system is limited to the geoid, and can only measure original time according to the SI second definition on the geoid. Time users on other non-geoid surfaces do not measure original time according to the SI second definition. Technical issues

[0007] How to achieve a decentralized four-dimensional spatiotemporal benchmark unification and establish a long-term stable time unification method traceable to the SI second definition in a separate centroid coordinate system has become an urgent problem to be solved. Technical solutions

[0008] To address the technical problems existing in the prior art, the present invention aims to provide a decentralized four-dimensional spatiotemporal benchmark unification method and timekeeping device, which operates a decentralized feedback mechanism to achieve time unification among multiple timekeeping devices.

[0009] To achieve the above-mentioned objectives, this invention proposes a decentralized method for unifying four-dimensional spatiotemporal benchmarks, comprising the following steps:

[0010] Step S1: Set up at least three timekeeping devices at different locations in the coordinate system;

[0011] Step S2: Measure the local original time using a timekeeping device, and convert the measured original time into the origin coordinate time according to the calendar of the timekeeping device.

[0012] Step S3: Periodically compare the origin coordinates using a timekeeping device to generate multiple clock difference data tables;

[0013] Step S4: Check the conversion coefficients using the timekeeping device based on multiple clock difference data tables, and adjust the conversion coefficients according to the check results.

[0014] Step S5: Check the deviation using the timekeeping device based on the latest clock difference data table, and adjust the calendar of the deviation based on the check results to complete the unification of the four-dimensional spatiotemporal reference.

[0015] Step S6: Using a timekeeping device, the original time is converted into broadcast coordinate time based on the calendar that has been unified with the four-dimensional spatiotemporal reference and the original time measured locally. The broadcast coordinate time is then used to provide time information to other users at other times.

[0016] According to a technical solution of the present invention, the calculation formula for converting the original time to the origin coordinates is as follows:

[0017] Among them, t iWhen the origin coordinates are converted by the timekeeping device i;

[0018] t0 i It is the initial time of the timekeeping device i, which is a fixed value after initialization;

[0019] t di The time delay is the coordinate origin delay time of the timekeeping device i, obtained through the timekeeping device's calendar. di =d i / c, where c is the speed of light in vacuum (m / s), d i Let be the distance from the location of the broadcast antenna of timekeeping device i to the origin of the coordinate system, in meters;

[0020] k i It is a conversion factor, obtained through the calendar of the timekeeping device, and its unit is a dimensionless relative value.

[0021] τ i It is the local measurement of the original time on the timekeeping device i, in SI seconds;

[0022] The formula for converting original time to broadcast coordinates is:

[0023] In the formula t xi When the broadcast coordinates of timekeeping device i are;

[0024] In the above two equations, d i and k i In the calendar of timekeeping device i, the original local measurement value τ is used. i It can be found by index, or by using the independent variable τ. i The calendar formula can be used for calculation.

[0025] According to a technical solution of the present invention, in step S3, the pairwise comparison of the origin coordinates includes:

[0026] The timekeeping device traverses the coordinate system twice to obtain the origin coordinates of the other timekeeping devices, and calculates the difference between the timekeeping device and the origin coordinates of the other timekeeping devices in the coordinate system, referred to as "clock error," forming a clock error data table; the formula for calculating the difference between the timekeeping device and the origin coordinates of the other timekeeping devices in the coordinate system is:

[0027] Where: Δt ij It is the difference between the origin coordinates of timekeeping devices i and j in the coordinate system; t i and t j These are the origin coordinates of timekeeping devices i and j, respectively.

[0028] According to one technical solution of the present invention, in step S3, the principle for setting the frequency of pairwise comparisons is as follows:

[0029] The frequency of the pairwise comparisons must satisfy the requirement that the timekeeping device within the coordinates is traversed at least twice within the shortest epochal period; and the number of clock difference data tables retained by the timekeeping device must satisfy the requirement that they span at least one longest epochal period.

[0030] According to one technical solution of the present invention, step S4 specifically includes:

[0031] Step S41: Perform conversion coefficient check: The timekeeping device calculates its clock difference change rate with other timekeeping devices in the coordinate system based on multiple clock difference data tables, and generates a clock difference change rate table;

[0032] The formula for calculating the rate of change of clock bias is:

[0033] In the formula: D ij (m) It is the rate of change of clock difference of timekeeping devices i and j; Δt ij (m) It is the difference in origin coordinates of timekeeping devices i and j in the clock difference data table formed by the m-th pairwise comparison; Δt ij (m-1) It is the difference in origin coordinates between timekeeping devices i and j in the clock difference data table formed by the (m-1)th pairwise comparison;

[0034] Step S42: The timekeeping device calculates and determines whether the average value of the clock difference change exceeds the limit value of the clock difference change rate based on the clock difference change rate table;

[0035] If yes, proceed to step S44; otherwise, proceed to step S5.

[0036] Step S44: The timekeeping device performs conversion coefficient calendar adjustment, and the conversion coefficient of the timekeeping device that has completed the conversion coefficient calendar adjustment is checked. The initial time of the timekeeping device that has reached the conversion coefficient check limit after adjustment is assigned a value.

[0037] According to one technical solution of the present invention, step S44 specifically includes:

[0038] The conversion coefficient calendar of the timekeeping device is repeatedly adjusted, and the conversion coefficient of the adjusted timekeeping device is checked to ensure that the clock error change rate of the adjusted timekeeping device is less than the clock error change rate limit, until convergence and stability, so that the timekeeping device that has completed the conversion coefficient calendar adjustment meets the adjustment conversion coefficient check limit condition.

[0039] The conversion coefficient check limit condition is:

[0040] In the formula: The average rate of change of clock difference of timekeeping device i after the m-th pairwise comparison; This is the limit for the rate of change of clock bias;

[0041] For timekeeping devices that have reached the conversion factor check limit after adjustment, the initial clock error is corrected according to the following formula:

[0042] In the formula: i is the serial number of the timekeeping device. It is the average value of the origin coordinates of all timekeeping devices except timekeeping device i in the coordinate system.

[0043] According to one technical solution of the present invention, step S5 specifically includes:

[0044] Step S51: Based on the latest clock difference data table, calculate the average deviation of the timekeeping devices and select the timekeeping devices with the largest average deviation that is greater than the deviation limit as those with excessive deviation.

[0045] Step S52: The over-biased one actively adjusts the distance from the broadcast antenna position in its history table to the origin of the coordinate system until the average deviation of the over-biased one does not exceed the deviation limit.

[0046] According to a technical solution of the present invention, in step S6, time synchronization is performed for other time users using the broadcast coordinates, specifically including:

[0047] The timekeeping device generates a timestamp based on the broadcast coordinates and the location coordinates of the broadcast antenna, and broadcasts it through the broadcast antenna to provide time synchronization for other users.

[0048] According to one aspect of the present invention, a timekeeping device is provided for implementing the above-described decentralized four-dimensional spatiotemporal reference unification method, comprising:

[0049] The original clock is used to locally measure the original time of the timekeeping device;

[0050] The coordinate time clock is used to convert the original time measured by the original time clock into origin coordinate time and broadcast coordinate time;

[0051] The comparison antenna is used to communicate with other timekeeping devices and obtain comparison information based on the origin coordinates.

[0052] The timing unit is used to generate a timestamp based on the broadcast coordinates and the broadcast antenna position coordinates of the timekeeping device;

[0053] A broadcast antenna is used to broadcast timestamps unidirectionally to time users in its vicinity, and to provide time synchronization to other time users through the timestamps;

[0054] The clock difference comparison unit is used to generate a clock difference data table and a clock difference change rate table based on the time comparison information of the origin coordinates, and to perform conversion coefficient checks and deviation checks.

[0055] The calendar unit is used to record the calendar of the timekeeping device and adjust the calendar according to the results of the conversion coefficient check and the deviation check. Beneficial effects

[0056] This invention proposes a decentralized four-dimensional spatiotemporal benchmark unification method, establishing a long-term stable time unification method traceable to the SI second definition. It provides a solution to the problem of inconsistent clock readings caused by relativistic effects or hardware drift instability when multiple timekeeping devices on the surface of celestial bodies with centers of mass and in their nearby orbits operate independently. This solves the problem that timekeeping systems on Earth are limited to the geoid, making it difficult for users to measure original time according to the SI second definition at other times. It also solves the problem that different original times within the same coordinate system cannot be directly compared due to relativistic effects. Attached Figure Description

[0057] Figure 1 schematically illustrates a flowchart of a decentralized four-dimensional spatiotemporal benchmark unification method provided in one embodiment of the present invention;

[0058] Figure 2 schematically illustrates the distribution of a timekeeping device in a four-dimensional spatiotemporal coordinate system according to an embodiment of the present invention;

[0059] Figure 3 schematically illustrates the working principle of a timekeeping device according to an embodiment of the present invention. Embodiments of the present invention

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0061] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the embodiments of the present invention are not limited to the following embodiments.

[0062] As shown in Figure 1, the decentralized four-dimensional spatiotemporal benchmark unification method provided by the present invention includes the following steps:

[0063] Step S1: Set up at least three timekeeping devices at different locations in the coordinate system;

[0064] Step S2: Measure the local original time using a timekeeping device, and convert the measured original time into the origin coordinate time according to the calendar of the timekeeping device.

[0065] Step S3: Periodically compare the origin coordinates using a timekeeping device to generate multiple clock difference data tables;

[0066] Step S4: Check the conversion coefficients using the timekeeping device based on multiple clock difference data tables, and adjust the conversion coefficients according to the check results.

[0067] Step S5: Check the deviation using the timekeeping device based on the latest clock difference data table, and adjust the calendar of the deviation based on the check results to complete the unification of the four-dimensional spatiotemporal reference.

[0068] Step S6: Using a timekeeping device, the original time is converted into broadcast coordinate time based on the calendar that has been unified with the four-dimensional spatiotemporal reference and the original time measured locally. The broadcast coordinate time is then used to provide time information to other users at other times.

[0069] This invention provides a method for unifying the time of a spatiotemporal reference in a centroid coordinate system other than Earth (such as the centroid coordinate systems of the Moon, Mars, Jupiter's satellites, and Mars' satellites), solving the problem that different original times within the same coordinate system cannot be directly compared due to the influence of relativistic effects.

[0070] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0071] The following terms are reiterated in this embodiment:

[0072] Centroid coordinate system: A coordinate system whose origin is located at the center of mass of the system, and whose origin is agreed upon by all observers.

[0073] Timekeeping device: A device that independently measures the original time, participates in system feedback, and transmits coordinates.

[0074] Original time: The time measured locally on the timekeeping device according to the SI second definition.

[0075] Coordinate time: Time measured in SI seconds by a clock at the origin of the centroid coordinate system or at infinity. Coordinate time cannot exist physically; it can only be converted from the measured original time to coordinate time through calculation. When simultaneity is present, the clock can be corrected to adjust its time scale (or time unit, clock step, clock speed, etc.) and time can be measured directly according to the coordinate time scale. The reading of this clock can then be used as coordinate time.

[0076] Ephemeris: A list of spatial parameters that change over time, with time indices corresponding to the values ​​of the spatial parameters. It can also be represented by a time-varying function. The spatial parameters include, but are not limited to, spatial coordinate values ​​and coordinate-time conversion coefficients.

[0077] The period of time table: the period during which spatial parameters change over time in the time table. When multiple periods are superimposed, the period with the largest change in the amplitude of spatial parameters is taken as the time table period.

[0078] Timestamp: The four-dimensional coordinates of a broadcast antenna. It provides the antenna's location and time information to the coverage area in the form of omnidirectional propagation of electromagnetic wave signals. The four-dimensional coordinates include three spatial coordinates and one time value.

[0079] In one embodiment of the present invention, a decentralized four-dimensional spatiotemporal reference unification method is provided, comprising six steps: measuring the original time, calculating the coordinate time, comparing the coordinate time, checking the adjustment conversion coefficient, checking the adjustment deviation, and broadcasting the timestamp. Specifically, it includes:

[0080] Step S1: Set up at least three timekeeping devices at different locations in the coordinate system;

[0081] The timekeeping device can be positioned either fixed on the surface of a celestial body or orbiting the celestial body with a satellite.

[0082] Step S2: Measure the local original time using a timekeeping device, and convert the measured original time into the origin coordinate time according to the calendar of the timekeeping device.

[0083] When calculating coordinates, the conversion formula is used to calculate the two types of coordinates corresponding to the origin: origin coordinates and broadcast coordinates.

[0084] Origin coordinates are the coordinates at the origin of the coordinate system. The simultaneity of four-dimensional spacetime can be checked by comparing the clocks of pairwise timekeeping devices. Origin coordinates are represented by the symbol t. i The calculation formula is as follows: (1)

[0085] In the formula: t i When the origin coordinates are converted by the timekeeping device i;

[0086] t0 i It is the initial time of the timekeeping device i, which is a fixed value after initialization;

[0087] t di The time delay t is the coordinate origin delay time of the timekeeping device i. di =d i / c, where c is the speed of light in vacuum (m / s), d i d is the distance from the broadcast antenna position of timekeeping device i to the origin of the coordinate system, in meters. i You can query it through the history table;

[0088] k iThese are conversion coefficients, unit: relative value, dimensionless, k i You can query it through the history table;

[0089] τ i It is the original time measured by the timekeeping device i, that is, the reading of the original clock on the timekeeping device, in SI seconds.

[0090] Broadcast coordinates are used to provide timestamps to time synchronization units for use by other time users. The symbol 't' is used when broadcasting coordinates. xi The calculation formula is as follows: (2)

[0091] In the formula t xi When the broadcast coordinates are converted by the timekeeping device i, they are used to construct the timestamp.

[0092] In formulas (1) and (2), the original time τ i It is a uniformly increasing value, representing the uniform passage of local time. Where d i and k i In the calendar of timekeeping device i, the original local measurement value τ is used. i It can be found by index, or by using the independent variable τ. i The calendar formula can be used for calculation.

[0093] In formulas (1) and (2), the conversion coefficient k i It is a value to be adjusted, a relatively stable small quantity. If the timekeeping device i is fixed on the surface of a celestial body, k i The magnitude is related to the position and altitude of the original clock of timekeeping device i and the tidal gravitational potential of the celestial body where timekeeping device i is located. The value of k for timekeeping device i is known during initialization. i An almanac, the original time τ measured by a timekeeping device. i As a time index, the calendar table is used to obtain the real-time k. i Quantity; If the timekeeping device i orbits the satellite around a celestial body, and the satellite is not acted upon by any force other than gravity, the satellite's motion is geodesic motion, also known as free fall motion, at which point k i The value is a small, stable quantity, and the conversion factor k only needs to be adjusted when track parameters change (such as track changes or track maintenance). i When using the historical table, the conversion factor k is used. i A one-time adjustment of the calendar, during normal operation k i All calendars do not require adjustment.

[0094] In formula (1), the origin delay time t di The real-time changes can be found in the calendar; the d value of the timekeeping device i is initialized during the initialization process. i The ephemeris is known information, and the original time τ is measured using a timekeeping device. i As a time index, the real-time t is obtained by looking up the table.di or d i Quantity. If the timekeeping device i is fixed on the surface of a celestial body, then d i It is a fixed value; if the timekeeping device i orbits the satellite around the celestial body, d i It is represented using an ephemeris. When the origin of the coordinate system is not yet determined, d i The calendar also has values ​​that need to be adjusted.

[0095] In formula (1), the initial time t0 i When another timekeeping device j already exists in the coordinate system, timekeeping device i is added to the coordinate system to eliminate initial clock bias. All timekeeping devices, when their original times are converted to the origin coordinates, should satisfy the simultaneity condition of four-dimensional spacetime. When timekeeping device i is newly added to the coordinate system, its initial time t0... i It should be adjusted to (3)

[0096] In the formula: It is the average value of the origin coordinates of all timekeeping devices except timekeeping device i in the coordinate system.

[0097] The simultaneity condition of four-dimensional spacetime is stated as follows: the coordinates at the origin within the coordinate system are unique; at any given moment, a clock located at any location other than the origin must guarantee that its time, after being transformed to the origin coordinates, will possess synchronicity and timeliness. This can be expressed as: (4)

[0098] In the formula: t0 is the ideal, unified origin coordinate, which is unique, and its unit is SI seconds; t i It is a timekeeping device i When reading the origin coordinates from the location; It is the distance from the clock of the timekeeping device i to the origin of the coordinate system, in meters; It is a position vector that can be found in the ephemeris, and c is the vacuum speed of light constant.

[0099] Synchronization at the origin coordinates is guaranteed by the third term on the right side of equation (1), namely the original time definition and the coordinate time conversion coefficient, which is called time scale conversion, from the original time SI second scale to the coordinate time scale. The effect of the conversion is to keep the clock speed of the coordinate time clocks of each timekeeping device in the system synchronized.

[0100] Simultaneity at the origin coordinates is the first term on the right-hand side of equation (1), with initial time t0. i Guaranteed. Simultaneously with the addition of the new timekeeping device, the initial time t0 is adjusted according to formula (3). i The assignment inherits the initial epoch of the existing timekeeping device, eliminating the initial deviation and making the new addition simultaneous with the existing ones.

[0101] Step S3: Periodically compare the origin coordinates using a timekeeping device within the coordinate system to generate multiple clock difference data tables;

[0102] The process of comparing origin coordinates involves multiple timekeeping devices at different locations comparing their origin coordinates in pairs, and then establishing a clock difference data table.

[0103] When comparing the origin coordinates, timekeeping device i compares the clocks bidirectionally with timekeeping device j via a relay satellite channel to eliminate channel delay errors. The direct comparison result is: (5)

[0104] Where: Δt ij It is the difference between the origin coordinates of timekeeping devices i and j; t i and t j When the origin coordinates of the timekeeping devices i and j are respectively, the clock difference should be zero when the ideal four-dimensional spacetime simultaneity condition is met.

[0105] Each timekeeping device needs to store the pairwise comparison results of all timekeeping devices to form a clock difference data table. Multiple clock difference data tables form a clock difference database. This clock difference database is stored in each timekeeping device, possessing decentralized characteristics and being difficult to modify or lose. During the comparison process, the two timekeeping devices exchange comparison data from all other timekeeping devices, resulting in the clock difference data table shown in Table 1 below:

[0106] Table 1

[0107] The pairwise comparisons are carried out in sequence until all timekeeping devices are traversed. The traversal order from smallest to largest is 12, 13, ..., 1n, 21, 23, ..., 2n, 31, 32, ..., 3n, ..., (n-1)1, (n-1)2, (n-1)3, ..., (n-1)n, n1, n2, n3, ..., n(n-1).

[0108] When performing pairwise comparisons, the frequency or interval of the comparison activities should ensure at least two iterations within the shortest calendar cycle, generating a new clock difference data table after each pairwise comparison. To retain as much historical data as possible, the number of clock difference data tables retained by the clock difference comparison unit in the timekeeping device should at least span one longest calendar cycle. The shortest calendar cycle refers to the time it takes for the fastest-moving timekeeping device to complete one rotation or revolution, while the longest calendar cycle refers to the time it takes for the slowest-moving timekeeping device to complete one rotation or revolution.

[0109] During the generation of the clock difference data table, the timekeeping devices are added sequentially according to the order in which they are added, with the newly added timekeeping device (referred to as the novice) having the highest serial number. When the coordinates of the original timekeeping device i in the coordinate system are adjusted, the cell in the i-th row and i-th column is assigned to the initial clock difference t. 0i In this embodiment, the coordinate clock adjustment of the timekeeping device is achieved by adjusting the calendar.

[0110] The process of adding a new timekeeper should not affect existing timekeeping devices. This can be achieved by marking the new timekeeper in the clock difference data table. For example, if the new timekeeper's serial number is n, the value in the nth row and nth column can be assigned as n, indicating that the new timekeeper will not participate in the comparison. The new timekeeper does not participate in the initial clock difference adjustment during the joining process. Instead, the new timekeeper's clock difference change rate is checked against that of other timekeeping devices, and its conversion factor k is repeatedly adjusted. n To ensure that the rate of change of clock error is less than the limit of the rate of change of clock error, until it converges and stabilizes within the range of the limit of the rate of change of clock error, the initial clock error of novice n can be corrected according to formula (3), and the initial clock error t of novice n can be set to... 0n The data is placed in the nth row and nth column of the clock difference data table to indicate that the novice can participate in the comparison within the coordinate system. If convergence fails, the clock difference data of novice n cannot be used by other timekeeping devices for inspection and adjustment, and the timekeeping device should be replaced or the calendar should be updated.

[0111] For timekeeping devices that adjust their coordinate clock midway, the adjustment process should ensure that it does not affect other timekeeping devices that are running in the coordinate system. Except for the serial number, the adjustment process of the timekeeping device that adjusts its coordinate clock is the same as the process of a new user joining.

[0112] Step S4: Check the conversion coefficients using the timekeeping device based on multiple clock difference data tables, and adjust the conversion coefficients according to the check results.

[0113] Step S4 specifically includes:

[0114] Step S41: Perform conversion coefficient check: The timekeeping device calculates its clock difference change rate with other timekeeping devices in the coordinate system based on multiple clock difference data tables, and generates a clock difference change rate table;

[0115] Step S42: The timekeeping device calculates and determines whether the average value of the clock difference change exceeds the limit value of the clock difference change rate based on the clock difference change rate table;

[0116] If yes, proceed to step S44; otherwise, proceed to step S5.

[0117] Step S44: The timekeeping device performs conversion coefficient calendar adjustment, and checks the conversion coefficient of the timekeeping device that has completed the conversion coefficient calendar adjustment. The initial time of the timekeeping device that passes the conversion coefficient check is assigned a value.

[0118] Step S44 specifically includes:

[0119] The conversion coefficient calendar of the timekeeping device is repeatedly adjusted once, and the conversion coefficient of the adjusted timekeeping device is checked to ensure that the clock error change rate of the adjusted timekeeping device is less than the limit value of the clock error change rate, until convergence and stability, so that the timekeeping device that has completed the conversion coefficient calendar adjustment passes the conversion coefficient check; the initial clock error of the timekeeping device that passes the conversion coefficient check is corrected.

[0120] The clock error change rate refers to the difference between clock error data at the same position in the clock error data table formed by two adjacent pairwise comparisons. Each timekeeping device finds its own sequence number from the clock error database. For example, taking sequence number i as the object of study, the comparison clock error data for timekeeping device i is listed according to the traversal time, forming the clock error change rate table as follows:

[0121] Table 2

[0122] The rate of change of clock bias is then calculated as follows:

[0123] D ij (m) =Δt ij (m) -Δt ij (m-1) i≠j, (6)

[0124] In the formula: D ij (m) It is Δt ij The rate of change of clock bias; Δt ij (m) It is the difference in origin coordinates of timekeeping devices i and j in the clock difference data table formed by the m-th pairwise comparison; Δt ij (m-1) It is the difference between the origin coordinates of timekeeping devices i and j in the clock difference data table formed by the (m-1)th pairwise comparison.

[0125] The adjustment conversion coefficient is checked by each timekeeping device to check the clock difference database. After each pairwise comparison and traversal, a new clock difference change rate table is formed. The clock difference change rate of itself and other timekeeping devices is calculated. For example, if the average value of the clock difference change rate according to formula (5) exceeds the limit, the conversion coefficient table adjustment is required. The value i can also be assigned to the i-th row and i-th column of the clock difference data table to mark the timekeeping device i. The marked timekeeping device i does not participate in the initial time adjustment of other timekeeping devices in the coordinate system.

[0126] The timekeeping device checked by the conversion factor should meet the following requirements: (7)

[0127] In the formula: D represents the average rate of change of clock error of timekeeping device i after the m-th pairwise comparison; lim To set the limit for the rate of change of clock bias, a limit D for the rate of change of clock bias is set at the beginning of the coordinate system establishment. lim The maximum rate of change of clock error for the first three timekeeping devices is given; the limit D is set after the fourth and subsequent devices are added. lim The number of timekeeping devices in the system should be gradually reduced, but should always be kept at least three.

[0128] Exceeding the limit D of the rate of change of clock bias lim The i-th timekeeping device exits the simultaneity check, but the pairwise comparison continues, generating clock difference comparison data and adjusting k. i After the table is completed, refer to the instructions for beginners to add programs. After checking that the requirements are met, modify the value of the i-th row and i-th column to the initialization time t calculated according to (3). 0i How to adjust k i Many technologies for calendars are already mature, such as PID control algorithms, Kalman filtering algorithms, AI algorithms, neural network algorithms, etc. This embodiment does not involve technical details.

[0129] Step S5: Check the deviation using the timekeeping device based on the latest clock difference data table, and adjust the calendar of the deviation based on the check results to complete the unification of the four-dimensional spatiotemporal reference.

[0130] Step S5 specifically includes:

[0131] Step S51: Based on the latest clock difference data table, calculate the average deviation of the timekeeping devices and select the timekeeping devices with the largest average deviation that is greater than the deviation limit as those with excessive deviation.

[0132] Step S52: Adjust the distance d from the broadcast antenna position to the origin of the coordinate system in the ephemeris table for the over-biased antenna. i Until the deviation of the average value of those exceeding the tolerance does not exceed the deviation limit.

[0133] Checking for deviations is the process by which each timekeeping device detects a deviation and adjusts the calendar. The device to be adjusted should be selected based on the principle of "maximum deviation from the average value".

[0134] The principle of maximum deviation from the average means that in the clock difference data table, the average of the absolute values ​​of each row is calculated, and the row with the largest average value is selected.

[0135] (8)

[0136]

[0137] (10)

[0138] In the formula: The average of the absolute values ​​of the clock difference in the i-th row of the clock difference data table, also known as the average deviation of timekeeping device i; Δt ij The clock difference data in the i-th row and j-th column of the clock difference data table represents the difference in the origin coordinates of timekeeping devices i and j; M is the row number in the clock difference data table, selected from rows i=1,2,...n, where the row number M containing the maximum deviation from the average value is located. T is the average of the absolute values ​​of the clock difference in the Mth row; lim This is the deviation from the limit value.

[0139] If the condition of formula (9) is met, then the timekeeping device corresponding to the Mth row in the clock difference data table is called the over-biased device. The over-biased timekeeping device M should actively adjust the parameter d of the distance from the origin in the calendar table. M Other timekeeping devices do not require adjustment. For those with excessive deviation, the value T should be assigned to the cell in the Mth row and Mth column of the clock difference data table. lim The symbol is used as a marker to indicate that the over-biased device does not participate in the initial time adjustment of other timekeeping devices in the coordinate system.

[0140] Each time over-bias adjustment is performed, only one timing device is used to ensure the stability of the coordinate system and avoid confusion caused by multiple timing devices adjusting simultaneously. When T is already present... lim If a value appears in a certain row and column of the clock difference data table, other timekeeping devices should work normally and the deviation check represented by formulas (8), (9), and (10) should not be performed. Only after timekeeping device M has performed calendar adjustment and meets the requirements of formula (9) should the cell in row M and column M of the table be assigned a value of zero, and the deviation check and adjustment procedure be restarted. During coordinate system initialization, there are only three timekeeping devices in the clock difference data table, T... lim Set as .

[0141] Timekeeping device M adjustment d M The calendar method can be implemented using a trial-and-error approach, which will not be described in detail in this embodiment.

[0142] Step S6: Using a timekeeping device, the original time is converted into broadcast coordinate time based on the calendar that has been unified with the four-dimensional spatiotemporal reference and the original time measured locally. The broadcast coordinate time is then used to provide time information to other users.

[0143] In step S6, time synchronization is performed for other users using broadcast coordinates, specifically including:

[0144] The timekeeping device generates a timestamp based on the broadcast coordinates and the location coordinates of the broadcast antenna, and broadcasts it through the broadcast antenna to provide time synchronization for other users.

[0145] As shown in Figure 3, this embodiment also provides a timekeeping device for implementing the above-mentioned decentralized four-dimensional spatiotemporal benchmark unification method, including:

[0146] An original time clock is a time measuring device that reproduces the SI second according to the SI second definition, and performs local measurement of the original time of a timekeeping device. Currently, the technology uses a cesium atomic clock to reproduce the SI second. If the International System of Units (SI) redefines the SI second, the original time clock will be updated to the new SI recommended measuring device.

[0147] A coordinate time clock is a time measurement device that calculates the origin coordinates using formula (1) based on the original time clock, and calculates the broadcast coordinates using formula (2). The initialization time t used for the calculation... 0i When the timekeeping device i is newly added to the coordinate system, it is assigned a value by formula (3), and the distance d to the origin used for calculation is calculated. i and conversion coefficient k i From the original time τ i The index's epochal table cell is obtained.

[0148] The calendar unit records the calendar of the timekeeping device and adjusts the calendar based on the results of conversion factor checks and deviation checks. The calendar is the original time τ. i The list of index position coordinates and conversion coefficients, when calculating formulas (1), (2), and (3), can be found in the original time τ of the calendar. i The corresponding conversion coefficient (k value) column and broadcast antenna coordinates Column lookup data is used for formula calculations.

[0149] The comparison antenna is used to communicate with other timekeeping devices in the coordinate system to obtain comparison information when the origin coordinates are obtained. The comparison antenna is a radio transceiver antenna or an antenna that transmits and receives light signals using laser communication, requiring symmetrical transmission and reception channel delays.

[0150] The time synchronization unit generates timestamps for broadcast to other users. It obtains the broadcast coordinates from a coordinate clock and the position coordinates of the broadcast antenna from an ephemeris, then sets the broadcast coordinates to t. xi and the location coordinates of the broadcast antenna Composition of timestamps It is broadcast through a broadcast antenna so that time users within the broadcast coverage area can receive the timestamp information, thus achieving the goal of unifying time and space.

[0151] A broadcast antenna is used to broadcast timestamp information. The spatial coordinates of the broadcast antenna are represented in an ephemeris and serve as a spatial reference for the broadcast coverage area.

[0152] The clock difference comparison unit stores the clock difference data of all timekeeping devices in pairs, forming a clock difference data table and a clock difference change rate table. Based on the clock difference data table and clock difference change rate table, it performs conversion coefficient checks and deviation checks. It has the ability to store long-term historical data and retain a certain number of expanded timekeeping devices.

[0153] Figure 2 shows a schematic diagram of the distribution of timekeeping devices in a four-dimensional spacetime coordinate system. The origin of the coordinate system is at the center of mass of the system. There are three or more timekeeping devices distributed at different positions in the coordinate system. For example, timekeeping device 1 is fixed on the surface of a celestial body and moves with the celestial body; timekeeping device 2 is in free fall in a circular orbit near the celestial body; and timekeeping device 3 is in free fall in an elliptical orbit near the celestial body. Each device has its own ephemeris and its spatial coordinates are known at different times. , , By adjusting their respective conversion coefficients and deviations, the four-dimensional spatiotemporal simultaneity condition of formula (4) is satisfied, and the timekeeping device can achieve decentralized four-dimensional spatiotemporal benchmark unification.

[0154] The above description is merely one embodiment of the present invention and is not intended to limit the invention. Those skilled in the art will recognize that the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A decentralized four-dimensional space-time reference unification method, characterized in that, Includes the following steps: Step S1: Set up at least three timekeeping devices at different locations in the coordinate system; Step S2: Measure the local original time using a timekeeping device, and convert the measured original time into the origin coordinate time according to the calendar of the timekeeping device. Step S3: Periodically compare the origin coordinates using a timekeeping device to generate multiple clock difference data tables; Step S4: Check the conversion coefficients using the timekeeping device based on multiple clock difference data tables, and adjust the conversion coefficients according to the check results. Step S5: Check the deviation using the timekeeping device based on the latest clock difference data table, and adjust the calendar of the deviation based on the check results to complete the unification of the four-dimensional spatiotemporal reference. Step S6: Using a timekeeping device, the original time is converted into broadcast coordinate time based on the calendar that has been unified with the four-dimensional spatiotemporal reference and the original time measured locally. The broadcast coordinate time is then used to provide time information to other users at other times.

2. The decentralized four-dimensional spacetime reference unification method of claim 1, wherein, The formula for converting original time coordinates to origin coordinates is: , where t i When the origin coordinates of the timekeeping device i are transformed, t0 i This is the initial time of the timekeeping device i, which is a fixed value after initialization; t di The time delay is the coordinate origin delay time of the timekeeping device i, obtained through the timekeeping device's calendar. di =d i / c, where c is the speed of light in vacuum (m / s), d i k is the distance from the broadcast antenna position of timekeeping device i to the origin of the coordinate system, in meters; i It is a conversion factor, obtained through the calendar of the timekeeping device, and its unit is a dimensionless relative value; τ i The original time is the local measurement value of the original time on the timekeeping device i, in SI seconds; the calculation formula for converting the original time into broadcast coordinates is: In the formula t xi When the broadcast coordinates of timekeeping device i are given; d in the above two equations i and k i In the calendar of timekeeping device i, the original local measurement value τ is used. i index.

3. The decentralized four-dimensional spacetime reference unification method of claim 2, wherein, In the step S3, the pairwise comparison of the origin coordinate time includes: each time-keeping device traverses other time-keeping devices in the coordinate system twice, calculates the origin coordinate time difference between the time-keeping device and other time-keeping devices in the coordinate system, obtains the origin coordinate time difference between other time-keeping devices, and forms a clock difference data table; the calculation formula of the origin coordinate time difference between the time-keeping device and other time-keeping devices in the coordinate system is: , wherein: Δt ij is the origin coordinate time difference between the time-keeping device i and the time-keeping device j in the coordinate system; t i and t j are the origin coordinate times of the time-keeping device i and the time-keeping device j, respectively.

4. The decentralized four-dimensional spacetime reference unification method of claim 3, wherein, In step S3, the frequency of pairwise comparisons is set according to the following principle: the frequency of pairwise comparisons satisfies that the timekeeping device within the coordinates is traversed at least twice within the shortest calendar period; and the number of clock difference data tables retained by the timekeeping device is at least sufficient to span one longest calendar period.

5. The decentralized four-dimensional spacetime reference unification method of claim 3, wherein, Step S4 specifically includes: Step S41, performing a conversion coefficient check: The timekeeping device calculates its clock difference change rate with other timekeeping devices in the coordinate system based on multiple clock difference data tables, and generates a clock difference change rate table; the calculation formula for the clock difference change rate is: In the formula: D ij (m) It is the rate of change of clock difference of timekeeping devices i and j; Δt ij (m) It is the difference in origin coordinates of timekeeping devices i and j in the clock difference data table formed by the m-th pairwise comparison; Δt ij (m-1) It is the difference between the origin coordinates of timekeeping devices i and j in the clock difference data table formed by the (m-1)th pairwise comparison; Step S42: The timekeeping device calculates and judges whether the average value of the clock difference change exceeds the limit value of the clock difference change rate according to the clock difference change rate table; Step S43: If yes, proceed to step S44; otherwise, proceed to step S5; Step S44: The timekeeping device adjusts the conversion coefficient calendar table, and performs a conversion coefficient check on the timekeeping device that has completed the conversion coefficient calendar table adjustment, and assigns a value to the initial time of the timekeeping device that has reached the conversion coefficient check limit value after adjustment.

6. The decentralized four-dimensional spacetime reference unification method of claim 5, wherein, Step S44 specifically includes: repeatedly adjusting the conversion coefficient calendar of the timekeeping device, and checking the conversion coefficient of the adjusted timekeeping device to ensure that the clock error change rate of the adjusted timekeeping device is less than the clock error change rate limit, until convergence and stability, so that the timekeeping device that has completed the conversion coefficient calendar adjustment meets the conversion coefficient check limit condition; the conversion coefficient check limit condition is: In the formula: D represents the average rate of change of clock error of timekeeping device i after the m-th pairwise comparison; lim The clock error rate of change is the limit; for timekeeping devices that have reached the conversion coefficient check limit after adjustment, the initial clock error is corrected according to the following formula: In the formula: i is the serial number of the timekeeping device. It is the average value of the origin coordinates of all timekeeping devices except timekeeping device i in the coordinate system.

7. The decentralized four-dimensional spacetime reference unification method of claim 6, wherein, In step S5, the specific steps include: Step S51, calculating the average deviation of the timekeeping device according to the latest clock difference data table, and selecting the timekeeping device with the largest average deviation that is greater than the deviation limit as the over-deviation device; Step S52, the over-deviation device actively adjusts the distance from the broadcast antenna position in its timeline to the origin of the coordinate system until the average deviation of the over-deviation device does not exceed the deviation limit.

8. The decentralized four-dimensional spacetime reference unification method of claim 1, wherein, In step S6, the time synchronization for other time users is achieved using the broadcast coordinates. Specifically, this includes: the timekeeping device generates a timestamp based on the broadcast coordinates and the position coordinates of the broadcast antenna, and broadcasts it through the broadcast antenna to provide time synchronization for other time users.

9. A timekeeping device for implementing the decentralized four-dimensional spacetime reference unification method as claimed in any one of claims 1 to 8, characterized in that, include: The original clock is used to locally measure the original time of the timekeeping device; The coordinate clock is used to convert the original time measured by the original clock into the origin coordinate time and the broadcast coordinate time; the comparison antenna is used to communicate with other timekeeping devices to obtain the origin coordinate time comparison information; the time synchronization unit is used to generate a timestamp based on the broadcast coordinate time and the broadcast antenna position coordinates of the timekeeping device. A broadcast antenna is used to broadcast timestamps unidirectionally to time users in its vicinity, and to provide time synchronization to other time users through the timestamps; a clock difference comparison unit is used to generate a clock difference data table and a clock difference change rate table based on the origin coordinate time comparison information, and to perform conversion coefficient checks and deviation checks; an ephemeris unit is used to record the ephemeris of the timekeeping device, and to adjust the ephemeris based on the check results of the conversion coefficient check and the deviation check.

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