Continuous resolving method, device and equipment for world time and storage medium

Abstract

The invention discloses a world time continuous resolving method. The method comprises the following steps: acquiring a resolving result file of each session in a preset time range and preprocessing the resolving result file; unified constraint is applied to each session after preprocessing, and parameter partitioning and local parameter elimination are carried out; constructing a sliding time window in a target time range, parameterizing world time in the window by adopting a piecewise linear function, and establishing a mapping relationship between a session and a time node; constructing a sliding time window on a global time axis, collecting sessions in the window, overlapping an addition equation according to a session right, adding a time node smooth constraint, and jointly resolving a world time margin increment; and superimposing prior on a joint calculation result, recovering a tidal term, and generating a world time continuous sequence. The problems that an existing world time product based on daily parameter level combination is limited in time resolution, session level observation geometry and normal equation information utilization is insufficient, modeling differences of different session types are sensitive, and an existing reference frame is difficult to adapt are solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of space geodesy, and particularly relates to a continuous world time calculation method, device, equipment and storage medium. BACKGROUND

[0002] Earth orientation parameters are key conversion parameters for characterizing the spatial orientation of the International Terrestrial Reference Frame (ITRF) relative to the International Celestial Reference Frame (ICRF) over time, mainly including polar motion, universal time, changes in the length of the day, and the shift of the celestial pole, etc. Among them, universal time directly reflects the Earth rotation angle, and is a key parameter in high-precision applications such as the establishment and maintenance of time reference, satellite navigation and precise orbit determination, earthquake monitoring, and geodynamics research. Compared with other components of the Earth orientation parameter, the universal time has significant irregular changes in a short time scale and poor predictability, and at present, only the quasi-inertial reference system constructed by the Very Long Baseline Interferometry (VLBI) technology can realize independent and high-precision determination.

[0003] The existing world time service products are mainly released by the International Earth Rotation and Reference Systems Service (IERS), including the final series products provided by the Earth Rotation Center (such as IERS C04) and the rapid combination and prediction products released by the Rapid Service and Prediction Center (such as IERS Bulletin A). Such products usually adopt a daily parameter level combination strategy, that is, the daily world time solutions provided by different space geodetic technologies or different analysis centers are statistically weighted, and only the daily world time scalar and its formal uncertainty are retained. This strategy is simple to implement and stable to run, but has the following limitations: first, the session-level observation geometry information, normal equations and parameter correlation are greatly weakened or discarded in the combination process, and the differences in constraint strategies, parameterization methods and random models of different technologies or analysis centers are compressed into a single daily parameter, which is not conducive to optimal weighting and is easy to introduce systematic bias; second, the daily scale combination has inherent limitations in time resolution, and it is difficult to effectively depict the intra-daily and higher frequency world time changes, and high-frequency signals are easy to be smoothed or aliased, thereby affecting the timeliness and short-period accuracy of the product.

[0004] At the observational level, the integrated UTC product provided by IERS still fundamentally relies primarily on very long baseline interferometry (VLBI) observations, especially the 1-hour enhanced observation sessions (INT1 / INT2 / INT3) and 24-hour regular observation sessions (R1 / R4) organized by the International VLBI Analysis Centre (IVS). The 24-hour regular sessions are typically conducted twice a week, employing a global multi-baseline network comprising approximately ten or more radio telescopes. This provides excellent all-sky coverage and high redundancy, enabling robust separation of UTC, tropospheric zenith delay, station clock errors, and station coordinate corrections within a single session, thus jointly solving the complete set of Earth orientation parameters. However, the operational delay from the end of the observation to the generation of SINEX equations or formal solutions for this type of session is typically around two weeks, and time sampling is only twice a week, making it difficult to meet the needs of quasi-continuous monitoring of UTC. To improve the frequency of UTC updates, IVS schedules almost daily 1-hour enhanced observation sessions, utilizing a few long east-west baselines to achieve rapid UTC calculation, offering advantages such as timely updates and lower operational delays. However, due to the limitations of short-arc observations and small network structures consisting of only 2–3 stations, the enhanced session observation geometry is weak and the redundancy is limited. It is generally only suitable for estimating UTC (or UTC under strong constraints), and its solution accuracy is usually about 2–3 times lower than that of a complete conventional observation multi-baseline network session.

[0005] Under the aforementioned business model, existing technologies generally adopt an operational scheme of "enhanced observation for rapid updates + high-precision supplementation by conventional observations," but there are still significant shortcomings: On the one hand, enhanced observations are short-arc, small-network observations, which are highly sensitive to system effects such as the status of individual station equipment, tropospheric modeling errors, and clock anomalies. The Universal Time (UTC) solution is easily affected by station network geometric degradation and residual modeling errors, resulting in limited stability and reliability. On the other hand, although conventional observations can provide more accurate UTC and complete Earth orientation parameter solutions, their observation intervals and data processing delays are relatively long, making it difficult to reflect rapid changes in UTC in a timely manner. In addition, when enhanced and conventional observations use simple parameter-level parameter combinations at the daily scale, the differences between different session types in terms of observation modeling, constraint methods, and stochastic models are often "folded" into the estimation of UTC on a single day. This is not conducive to fully leveraging the advantages of various sessions and can easily lead to smoothing or aliasing of high-frequency UTC signals, affecting the short-cycle accuracy and timeliness of the product. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of limited time resolution, insufficient utilization of session-level observation geometry and normal equation information, sensitivity to modeling differences between different session types, and difficulty in adapting to the current reference frame in existing Universal Time (UTC) products based on daily parameter-level combinations. This invention proposes a method to achieve high time resolution, continuity, and high accuracy in UTC solutions by utilizing the normal equations of different session types in VLBI under the current reference frame and constraint strategy, thereby obtaining a continuous UTC sequence that balances timeliness and accuracy.

[0007] According to one aspect of the present invention, a method for continuous calculation of Universal Time is provided, comprising: Obtain the solution result files for each session within a predetermined time range and perform preprocessing; Apply uniform constraints to each session after preprocessing, and perform parameter block division and local parameter elimination; Construct a sliding time window within the target time range, parameterize world time using a piecewise linear function within the window, and establish a mapping relationship between sessions and time nodes; Construct a sliding time window on the global time axis, collect sessions within the window, superimpose the equations according to session weights, add time node smoothing constraints, and jointly solve the world time margin increment. Priors are superimposed on the joint solution results, and the tidal term is recovered to generate a continuous sequence of universal time.

[0008] As a further technical solution, the solution result files of each session within a predetermined time range are obtained and preprocessed, including: Based on the solution result files of each VLBI session within a predetermined time range, the session normal equations are written as follows: ,in, Let be the normal equation coefficient matrix for the s-th session; Let be the column vector of parameters to be estimated for the s-th session; Let be the column vector of constant terms in the normal equation for the s-th session; All station coordinates for all sessions are unified under the same Earth reference frame, and Universal Time tidal correction and incremental linearization are performed.

[0009] As a further technical solution, Universal Time tidal correction and incremental linearization processing are performed, including: Tidal correction is applied to Universal Time to obtain the Universal Time margin at time t. for: ,in, Let t be the world time. Let t be the world time tidal correction at time t; Based on the prior value and observed value of the world time margin, the world time margin increment is obtained, and the world time margin increment is substituted into the conversational method equation as one of the world time unknowns.

[0010] As a further technical solution, the column vector of parameters to be estimated includes at least: the world time surplus increment, the clock difference parameters of each VLBI station, and the tropospheric zenith delay parameters of each VLBI station.

[0011] As a further technical solution, a piecewise linear function is used within the window to parameterize world time, establishing a mapping relationship between sessions and time nodes, including: At any point between adjacent time nodes within the window, a piecewise linear function is used to approximate the increment of the world time balance; Introducing a representative epoch for the s-th session, where the representative epoch is located between the aforementioned adjacent time nodes, the world time residual increment is transformed using a piecewise linear function to obtain an approximate expression of the world time residual increment for the s-th session. By introducing the row vector corresponding to the time node of the s-th session, the approximate expression of the world time margin increment of the s-th session is transformed to obtain the final approximate expression of the world time margin increment. By substituting the final approximate expression of the world time margin increment into the reduction equation after local parameter elimination, a mapping relationship between sessions and time nodes is established.

[0012] As a further technical solution, the session weight superposition method equation is used, and time node smoothing constraints are added to jointly solve for the world time surplus increment, including: Within the j-th time window, all items belonging to the set The normal equations of the conversation are weighted and superimposed to obtain the normal equation coefficient matrix synthesized within the j-th time window. And the column vector of normal equation constant terms synthesized within the j-th time window. ; Time node parameters A second-order difference smoothing constraint is applied, where, Let T be the second-order difference operator matrix at time node k, and let T be the transpose. To smooth out the constraint weighting factors, Let be the column vector of the world time surplus increments for the time nodes to be estimated within the j-th time window. Then, the joint normal equations within the j-th time window are: , Solving the joint method equations yields an estimate of the cosmic time surplus increment at the j-th time window: , By sliding the time window along the time axis and repeating the solution process, continuous time node estimates are obtained over the entire target time range.

[0013] As a further technical solution, after obtaining the estimate of the world node's world time surplus increment, it also includes: By using prior world time series to recover the world time margin and combining it with piecewise linear interpolation, a continuous world time margin estimate is obtained. Based on the obtained Universal Time Residual Estimate, the tidal term is recovered, and a continuous Universal Time sequence is generated.

[0014] According to one aspect of the present invention, a continuous world time calculation apparatus is provided, comprising: The first main module is used to obtain the solution result files of each session within a predetermined time range and perform preprocessing. The second main module is used to apply uniform constraints to each session after preprocessing, and to perform parameter block division and local parameter elimination. The third main module is used to construct a sliding time window within the target time range, parameterize world time using a piecewise linear function within the window, and establish a mapping relationship between sessions and time nodes. The fourth main module is used to construct a sliding time window on the global time axis, collect sessions within the window, superimpose the normal equations according to session weights, add time node smoothing constraints, and jointly solve the world time margin increment. The fifth main module is used to superimpose priors on the joint solution results and recover the tidal term to generate a continuous sequence of universal time.

[0015] According to one aspect of the present invention, a continuous commencing time (UTC) calculation apparatus is provided, comprising a memory and a processor, wherein the memory stores program instructions that are executed by the processor, and the processor invokes the program instructions to execute the aforementioned continuous commencing time calculation method.

[0016] According to one aspect of the present invention, a non-transitory computer-readable storage medium is provided, the non-transitory computer-readable storage medium storing computer instructions that cause the computer to execute the aforementioned continuous world time calculation method.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention proposes a method for achieving high temporal resolution, continuity, and high precision solution of Universal Time (UTC) using VLBI normal equations for different session types under existing reference frames and constraint strategies. This method obtains a continuous UTC sequence that balances timeliness and accuracy, and solves the problems of limited temporal resolution, insufficient utilization of session-level observation geometry and normal equation information, sensitivity to modeling differences between different session types, and difficulty in adapting to existing reference frames in existing UTC products based on daily parameter-level combinations. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating a continuous world time calculation method provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram comparing the comprehensive solution of world time provided in an embodiment of the present invention with the official product. Detailed Implementation

[0021] The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that includes a series of steps or units, not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined to form new technical solutions. Such combinations are not bound by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0023] This invention provides a method for continuous calculation of world time, referring to... Figure 1 As shown, the process includes five main steps: observation data acquisition and preprocessing, unified modeling of session-level normal equations, continuous parameterization of Universal Time and construction of time grids, fusion and joint solution of normal equations within a sliding time window, and restoration and generation of continuous Universal Time sequences. Under the existing reference framework and constraint strategy, the process utilizes normal equations of different session types of VLBI to achieve high temporal resolution, continuity, and high precision in Universal Time solution, thereby obtaining a continuous Universal Time sequence that balances timeliness and accuracy.

[0024] The term "session" in this invention refers to a single, independently scheduled and computed VLBI observation experiment (such as INT or RAP).

[0025] The specific implementation process of the continuous world time calculation method described in this embodiment of the invention is as follows: Step 1: Acquisition and preprocessing of observation data.

[0026] 1) Acquisition of session-level normal equations Preferably, the solution result files for each VLBI session within a predetermined time range are obtained from the International VLBI Analysis Center. Let there be S sessions within this time range, then the s-th session... The session-level normal equation is written as: , In the formula, Let be the normal equation coefficient matrix for the s-th session; Let be the column vector of parameters to be estimated for the s-th session; Let be the column vector of constant terms in the normal equation for the s-th session. Where is the parameter vector. It should include at least: UTC-related parameters (such as UTC margin increments); clock error parameters for each VLBI station; tropospheric zenith delay parameters for each VLBI station; and, if necessary, station coordinate corrections.

[0027] 2) Reference frame and station coordinates are unified To ensure consistency across different sessions, this step unifies the station coordinates of all sessions to the same Earth reference frame (e.g., ITRF2020).

[0028] 3) Universal Time Tidal Correction To facilitate subsequent continuous processing, this invention removes short-period tidal effects from Universal Time (UTC) and defines a Universal Time Residual (UT1R). Let: For world time at time t; Let t be the world time tidal correction at time t; Let be the world time margin at time t. Then we have: , In the formula, It can be calculated from a pre-given tidal model, and is generally written as the sum of multiple harmonic components: , in, The number of tidal components used; for each tidal component : The amplitude of the cosine term; The amplitude of the sinusoidal term; This is the angular frequency of the component.

[0029] 4) Linearization of world time increment To solve within a unified incremental framework, this invention selects a long-term universal time reference sequence as a priori value. Let: Let be the world time margin prior value at time t; let be the representative epoch of the s-th session. ; The world time margin observation value obtained from the solution of the s-th session; Let be the world time margin increment for the s-th session. Then the world time margin increment is defined as: , Then, As one of the unknown quantities of world time, it is substituted into the conversational equation shown in formula (1) so that each conversation is represented on a unified prior basis.

[0030] Step 2: Unified modeling of session-level normal equations.

[0031] 1) Unified constraint strategy and normal equation correction To ensure that each session solves under a unified reference frame and constraint rules, this invention applies uniform no-offset / no-rotation constraints to each session. Therefore: , In the formula, Let be the constraint coefficient matrix for the s-th session; Let be the constraint matrix for the s-th session; Let be the column vector of constraint constant terms for the s-th session; The coefficient matrix of the normal equations after applying constraints; This is the vector of constant terms in the normal equation after constraints are applied.

[0032] 2) Parameter partitioning and local parameter elimination The column vector of parameters to be estimated for the s-th session The blocks are as follows: , In the formula, This is a column vector consisting of other parameters of the session, such as station clock error, tropospheric zenith delay, and station coordinate correction.

[0033] Substitute formula (6) into formula (5), and... The blocks are written as follows: , In the formula, for The relevant scalar equation coefficients; This is a row vector of coupling coefficients between world time and other parameters; for The transpose (column vector); column vector The coefficient matrix of the normal equations.

[0034] Accordingly, The blocks are as follows: , in, To and Related scalar constant terms; For column vectors The relevant constant term column vector.

[0035] By using Schul complement, the column vector Elimination yields only information about... The reduced equation: , In the formula, The equivalent weight coefficients for world time direction after elimination are defined as follows: , The equivalent constant term for world time direction after elimination is defined as: , at this time, As a scalar, As scalars, they collectively represent the "equivalent observation" and "equivalent weight" of the s-th session in the world time direction.

[0036] Step 3: Continuous parameterization of world time and construction of time grid.

[0037] 1) Setting time nodes Let the target time range of this invention be: ,in, The starting time; The end time is specified. Within this time range, a fixed time interval is selected. Set time nodes: , In the formula, Let K be the time of the kth world time node; K is the total number of time nodes.

[0038] Let the increments of the world time remainder at all time points form a column vector: , In the formula, For a moment The increment of the remaining amount in the world is unknown.

[0039] 2) Time interpolation and session-node relationship At any time Within this invention, a piecewise linear function is used to approximate the world time residual increment: , In the formula, The interpolation weights are defined as follows: , Let the representative epoch of the s-th session be . And satisfy Then the world time margin increment for this session can be approximated as: , In the formula, For session s, the interpolation coefficients relative to node k; Let be the interpolation coefficients of session s relative to node k+1.

[0040] Define the row vector corresponding to the time node of the s-th session. for: , In the formula, for A 3D column vector, where all elements except the k-th and (k+1)-th elements are 0; the k-th element is... The (k+1)th element is Therefore, we can conclude that: , Substituting formula (18) into the session reduction equation (9), we obtain the session time node parameters. Contributions: , make The normal equation coefficient matrix represents the contribution of the s-th session to the time node parameters; The column vector of the constant terms of the normal equation representing the contribution of the s-th session to the time node parameters can then be written as: , Step 4: Fusion and joint solution of normal equations within the sliding time window.

[0041] 1) Construction of sliding time window To improve numerical stability and facilitate time series smoothing, this invention constructs a sliding time window on the global time axis. Let: The length of the time window is ; the center time of the j-th time window is . The time interval covered by the j-th time window is ; For all representative eras The set of sessions that fall within this time interval.

[0042] 2) Superposition and weighting of normal equations within the time window Within the j-th time window, this invention will include all elements belonging to the set We perform a weighted superposition of the conversational equations. Let: The weight factor for the s-th session (determined based on residual statistics); Let be the normal equation coefficient matrix synthesized within the j-th time window; Let be the column vector of constant terms of the normal equation synthesized within the j-th time window, then we have: , To constrain the smoothness of time series and suppress ill-conditioned solutions, this invention modifies the time node parameters. A second-order difference smoothing constraint is applied. Let: The second-order difference operator matrix for time nodes; To smooth out the constraint weighting factor; This is the column vector of the incremental cosmic time balance of the time node to be estimated within the j-th time window.

[0043] The joint normal equation within the j-th time window is: , Solving formula (22) yields the estimated time points within the time window: , In the formula, This is the estimated vector of the world time surplus increment at time node j within the j-th time window. By sliding the time window along the time axis and repeating the above process, continuous time node estimates can be obtained over the entire target time range.

[0044] Step 5: Universal Time Continuous Sequence Recovery and Product Generation.

[0045] 1) Recovering the Universal Time Margin from Incremental Recovery After obtaining the time node increment estimate, this invention utilizes prior world time series to recover the world time residual. Let: Time node Estimation of the world time surplus increment (i.e. The k-th component); Time node Given the estimated world time surplus, we have: , For any time A continuous world time residual estimate is obtained by using piecewise linear interpolation: , 2) Recover the tidal term and generate a continuous sequence of Universal Time. Finally, this invention recalculates the tidal correction at time t in universal time based on the adopted tidal model. Then add it back to the UT balance to obtain a continuous estimate of UT: , In the formula, This is the world time at time t calculated by the present invention; This is the estimated world time margin at time t; Let t be the tidal correction at time t in the world.

[0046] Through the above steps, under the existing reference frame and unified constraint strategy, this invention jointly utilizes session-level normal equation information from enhanced and conventional observations to obtain a continuous Universal Time (UTC) solution sequence with high temporal resolution and high accuracy. It can also generate continuous UTC products at predetermined sampling intervals and perform corresponding accuracy assessments, as shown in Table 1 and... Figure 2 As shown.

[0047] Table 1. Weighted root mean square of world time residuals from weighted observations, conventional observations, and integrated solutions (unit: microseconds) .

[0048] As shown in Table 1, enhanced observation is continuous but not very accurate, while conventional observation is accurate but not continuous. The solution of this invention can simultaneously meet the requirements of high accuracy and continuity.

[0049] The implementation of the various embodiments of the present invention is based on programmed processing through a device with processor functionality. Therefore, in practical engineering, the technical solutions and functions of the various embodiments of the present invention are encapsulated into various modules. Based on this reality, and building upon the above embodiments, the embodiments of the present invention provide a continuous world time (UTC) calculation apparatus, which is used to execute a UTC continuous calculation method from the above method embodiments.

[0050] The device includes: a first main module for acquiring and preprocessing the solution result files of each session within a predetermined time range; a second main module for applying uniform constraints to each preprocessed session and performing parameter block division and local parameter elimination; a third main module for constructing a sliding time window within a target time range, parameterizing Universal Time using a piecewise linear function within the window, and establishing a mapping relationship between sessions and time nodes; a fourth main module for constructing a sliding time window on a global time axis, collecting sessions within the window, superimposing the equations according to session weights, adding time node smoothing constraints, and jointly solving for the Universal Time residual increment; and a fifth main module for superimposing priors on the joint solution results, recovering the tidal term, and generating a continuous Universal Time sequence.

[0051] This invention provides a continuous Universal Time (UTC) solution device that addresses the problems of limited time resolution, insufficient utilization of session-level observation geometry and normal equation information, sensitivity to modeling differences between different session types, and difficulty in adapting to the current reference frame in existing UTC products based on daily parameter-level combinations. By employing the aforementioned modules, under the current reference frame and constraint strategy, it utilizes the normal equations of different session types in VLBI to achieve high time resolution, continuity, and high accuracy in UTC solution, thereby obtaining a continuous UTC sequence that balances timeliness and accuracy.

[0052] It should be noted that the device embodiments provided by the present invention are used not only to implement the methods in the above method embodiments, but also to implement the methods in other method embodiments provided by the present invention. The only difference is that corresponding functional modules are set. The principle is basically the same as that of the above device embodiments provided by the present invention. As long as those skilled in the art can improve the modules in the above device embodiments by referring to the specific technical solutions in other method embodiments and combining technical features to obtain corresponding technical means and technical solutions composed of these technical means, on the basis of the above device embodiments, and on the premise of ensuring the practicality of the technical solutions, they can obtain corresponding device-type embodiments for implementing the methods in other method-type embodiments.

[0053] Based on the same inventive concept as any of the foregoing embodiments, this embodiment of the invention also provides a continuous world time calculation device, including a memory and a processor. The memory stores program instructions that are executed by the processor, and the processor calls the program instructions to execute the continuous world time calculation method.

[0054] In embodiments of the present invention, the memory can be non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), or it can be volatile memory, such as random-access memory (RAM). Memory is any other medium capable of carrying or storing desired program code having an instruction or data structure form and accessible by a computer, but is not limited thereto. The memory in embodiments of the present invention can also be a circuit or any other device capable of implementing a storage function for storing program instructions and / or data.

[0055] In this embodiment of the invention, the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in this embodiment of the invention. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in this embodiment of the invention can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

[0056] Based on the same inventive concept as any of the foregoing embodiments, this embodiment of the invention also provides a non-transitory computer-readable storage medium storing computer instructions that cause the computer to execute the following method for continuous world time calculation: Obtain the solution result files for each session within a predetermined time range and perform preprocessing; Apply uniform constraints to each session after preprocessing, and perform parameter block division and local parameter elimination; Construct a sliding time window within the target time range, parameterize world time using a piecewise linear function within the window, and establish a mapping relationship between sessions and time nodes; Construct a sliding time window on the global time axis, collect sessions within the window, superimpose the equations according to session weights, add time node smoothing constraints, and jointly solve the world time margin increment. Priors are superimposed on the joint solution results, and the tidal term is recovered to generate a continuous sequence of universal time.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for continuous solution of universal time, characterized by, The method comprises the following steps: obtaining and preprocessing the solving result files of each session within a predetermined time range; applying uniform constraints to each session after preprocessing, and performing parameter partitioning and local parameter elimination; constructing a sliding time window within a target time range, parameterizing the universal time by using a piecewise linear function within the window, and establishing a mapping relationship between the session and the time node; constructing a sliding time window on the global time axis, collecting the sessions within the window, superimposing the law equation according to the session weight, and adding a time node smoothing constraint to jointly solve the universal time residual increment; superimposing the priori on the joint solving result, recovering the tidal term, and generating a continuous universal time sequence.

2. The method of claim 1, wherein, The method comprises the following steps: Based on the result files of each VLBI session within a predetermined time range, the session equation is written as: wherein is the coefficient matrix of the law equation of the s-th session; is the column vector of the to-be-estimated parameters of the s-th session; is the column vector of the constant term of the law equation of the s-th session; unifying the station coordinates of all sessions to the same earth reference frame, and performing universal time tide correction and increment linearization processing.

3. The method of claim 2, wherein, The method comprises the following steps: The world time is corrected by the tide to obtain a world time residual at time t is: wherein, is the world time at time t; is the world time tide correction at time t; According to the universal time residual priori value and the universal time residual observation value, the universal time residual increment is obtained, which is one of the unknowns of the universal time and is substituted into the session law equation.

4. The method of claim 3, wherein, The to-be-estimated parameter column vector at least includes: the universal time residual increment, the clock bias parameters of each VLBI station, and the tropospheric zenith delay parameters of each VLBI station.

5. The method of claim 1, wherein, The method comprises the following steps: At any time between adjacent time nodes within the window, the universal time residual increment is approximated by using a piecewise linear function; The representative epoch of the s-th session is introduced, and the universal time residual increment approximated by using a piecewise linear function is converted to obtain an approximate expression of the universal time residual increment of the s-th session; The row vector of the corresponding time node of the s-th session is introduced, and the approximate expression of the universal time residual increment of the s-th session is converted to obtain the final approximate expression of the universal time residual increment; The final approximate expression of the universal time residual increment is brought into the reduced law equation after local parameter elimination to establish the mapping relationship between the session and the time node.

6. The method of claim 1, wherein: The method comprises the following steps: In the jth time window, all the session equation belonging to the set are weighted and superimposed to obtain the synthetic equation coefficient matrix in the jth time window, and the synthetic equation constant term column vector in the jth time window. At the time node parameter The second-order difference smoothing constraint is applied on top, is the second-order difference operator matrix at the time node k, and T is the transpose, is the smoothing constraint weight factor, is the time node world time residual increment column vector to be estimated within the jth time window, and the joint method equation within the jth time window is: ， Solving the joint law equation to obtain the estimation of the time node universal time residual increment within the j-th time window: ， Sliding the time window along the time axis and repeating the solving process to obtain the continuous time node estimation within the entire target time range.

7. The method of claim 6, wherein, After obtaining the estimation of the universal node universal time residual increment, the method further comprises the following steps: Using the priori universal time sequence to recover the universal time residual, and combining the piecewise linear interpolation to obtain the continuous universal time residual estimation; Based on the obtained universal time residual estimation, the tidal term is recovered to generate a continuous universal time sequence.

8. A continuous world time resolving apparatus, characterized by comprising: The method comprises the following steps: A first main module is used to obtain and preprocess the solving result files of each session within a predetermined time range; A second main module is used to apply uniform constraints to each session after preprocessing, and perform parameter partitioning and local parameter elimination; A third main module is used to construct a sliding time window within a target time range, parameterize the universal time by using a piecewise linear function within the window, and establish a mapping relationship between the session and the time node; A fourth main module is configured to build a sliding time window on a global time axis, collect sessions within the window, superimpose a session weight equation, and add a time node smoothing constraint to jointly solve a world time residual increment; A fifth main module is configured to superimpose a prior on the joint solution and restore a tidal term to generate a continuous sequence of world time.

9. A continuous world time resolving apparatus, characterized by comprising: A computer readable storage medium stores a program instruction, and a processor executes the program instruction to perform the method of any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium, comprising: The non-transitory computer readable storage medium stores computer instructions, and the computer instructions cause the computer to perform the method of any one of claims 1 to 7.

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