A method and system for dynamic updating of national height datum based on optical clock network

Abstract

The application discloses a national height datum dynamic updating method and system based on an optical clock network. The method is characterized in that: optical clock nodes are arranged at a height origin, a first-order leveling point, a GNSS continuous operation reference station and a crust movement monitoring area to construct an optical clock frequency comparison network; frequency comparison between nodes is performed by using an optical fiber time-frequency transmission link to measure gravity potential difference; GNSS coordinate change amount, absolute gravity change amount, tide model data, atmospheric pressure data, underground water change data and crust deformation monitoring data are synchronously acquired; a gravity potential dynamic correction model of multi-source information fusion is established to obtain real-time gravity potential change amount and dynamically update height values. The application realizes real-time dynamic updating of a centimeter-level-precision height datum, eliminates error accumulation of traditional leveling measurement and can be widely applied to fields such as height datum maintenance, major engineering construction and crust movement monitoring.

Description

Technical Field

[0001] This invention belongs to the fields of geodesy, time and frequency science, geodynamics monitoring and spatial information technology, and in particular relates to a method and system for dynamic updating of national elevation benchmarks based on optical clock networks. Background Technology

[0002] The establishment and maintenance of national elevation datums are of great significance for fields such as geographic information systems, engineering construction, resource management, and disaster monitoring. Traditional elevation measurement methods rely heavily on leveling, GNSS (Global Navigation Satellite System), and gravity measurements. While these methods meet accuracy requirements to a certain extent, they still have the following shortcomings in establishing large-scale, high-precision datums: (1) The national elevation datum has a long update cycle: the existing elevation datum is usually updated every few years or even decades, which makes it difficult to reflect the impact of crustal movement, land subsidence and sea level changes in a timely manner.

[0003] (2) Error accumulation in elevation transfer: There are problems of systematic error and random error accumulation in long-distance leveling.

[0004] (3) Lack of continuous monitoring capability: Traditional methods mainly adopt periodic measurement mode, which cannot achieve real-time maintenance of national elevation benchmark.

[0005] (4) Difficult to reflect dynamic gravity field changes: Tidal effect, atmospheric load, hydrological load and underground mass migration and other factors will cause gravity potential changes, which in turn affect the stability of elevation datum. Summary of the Invention

[0006] This invention addresses the problems of long update cycles, error accumulation, and lack of continuous monitoring capabilities in traditional national elevation benchmarks by providing a dynamic update method for national elevation benchmarks based on optical clock networks. The method first deploys multiple optical clock observation nodes at the elevation origin, first-order leveling points, continuously operating GNSS reference stations, and crustal movement monitoring areas to construct an optical clock frequency comparison network. Then, it uses fiber optic time-frequency transmission links to compare the frequencies of each optical clock node to determine the gravity potential difference between nodes. Simultaneously, it acquires GNSS coordinate changes, absolute gravity changes, tidal model data, atmospheric pressure data, groundwater change data, and crustal deformation monitoring data. Based on this, a multi-source information fusion gravity potential dynamic correction model is established. Corresponding correction amounts are calculated based on various data types, and the correction results are constrained and verified using absolute gravity changes to obtain real-time gravity potential changes. Finally, the elevation values ​​of each elevation control point are dynamically updated based on the conversion relationship between gravity potential and elevation, thus achieving real-time dynamic updates of the national elevation benchmark with centimeter-level accuracy. This effectively eliminates the error accumulation of traditional leveling measurements and establishes a nationwide continuous monitoring capability.

[0007] According to one aspect of this invention, a method for dynamically updating a national elevation benchmark based on an optical clock network is provided, comprising: deploying multiple optical clock observation nodes at the elevation origin, first-order leveling points, continuously operating GNSS reference stations, and crustal movement monitoring areas to construct an optical clock frequency comparison network; using the optical fiber time-frequency transmission link of the optical clock frequency comparison network to perform frequency comparison on each optical clock node and determine the gravity potential difference between nodes; and simultaneously acquiring GNSS coordinate changes, absolute gravity changes, tidal model data, atmospheric pressure data, groundwater change data, and crustal topography data. The system utilizes GNSS coordinate changes and crustal deformation monitoring data to establish a dynamic gravity potential correction model. It calculates crustal deformation corrections based on GNSS coordinate changes and crustal deformation monitoring data, and calculates tidal, atmospheric load, and groundwater change corrections based on tidal model data, atmospheric pressure data, and groundwater change data, respectively. The correction results are then constrained and verified using the absolute gravity change to obtain real-time gravity potential changes. Based on these real-time gravity potential changes and the conversion relationship between gravity potential and elevation, the elevation values ​​of each elevation control point are dynamically updated.

[0008] As a further technical solution, the optical clock node adopts a frequency stability better than 10. -18 The optical atomic clock is of the order of magnitude, with each node equipped with a femtosecond optical comb to achieve up-conversion and down-conversion with equal precision.

[0009] As a further technical solution, the optical fiber time-frequency transmission link of the optical clock frequency comparison network is used to perform frequency comparison on each optical clock node, including: using optical frequency dual-frequency or tri-frequency comparison technology to eliminate common-mode environmental noise during signal propagation and extract gravity frequency shift signal.

[0010] As a further technical solution, the multi-source information fusion gravity potential dynamic correction model includes: an optical clock observation submodule, a GNSS deformation monitoring submodule, an absolute gravity monitoring submodule, a tidal correction submodule, an atmospheric load correction submodule, a hydrological load correction submodule, and a crustal deformation monitoring submodule, and calculates the real-time gravity potential change using a weighted least squares estimation method.

[0011] As a further technical solution, the real-time change in gravitational potential is expressed as follows: ,in, The difference in gravitational potential between nodes; This is the tidal correction amount; This is the atmospheric load correction amount; This is a correction for changes in groundwater levels. This is a correction for crustal deformation; the absolute gravity change is used to adjust for... The calculation results are subjected to external constraints and accuracy verification.

[0012] As a further technical solution, the dynamic updating of the elevation values ​​of each elevation control point adopts a dynamic gravity potential-elevation conversion model: ,in, For the updated elevation, This is the initial elevation. This represents the dynamic change in gravitational potential. Let ε(t) be the local gravitational acceleration, and ε(t) be the environmental compensation term.

[0013] According to one aspect of this invention, a dynamic updating system for a national elevation datum based on an optical clock network is provided, comprising: an optical clock observation module deployed at the elevation origin, first-order leveling points, GNSS continuously operating reference stations, and crustal movement monitoring areas, for providing frequency references and time-frequency signals; an optical fiber time-frequency transmission module for connecting each optical clock observation node to achieve frequency synchronization and frequency comparison between nodes; a frequency comparison module for acquiring observed frequency differences between optical clock nodes; a gravity potential calculation module for converting the observed frequency differences into gravity potential differences between nodes based on the principle of gravity frequency shift in general relativity; a multi-source data fusion module for fusing GNSS coordinate changes, absolute gravity changes, tidal model data, atmospheric pressure data, groundwater change data, and crustal deformation monitoring data to establish a dynamic correction model for gravity potential based on multi-source information fusion and dynamically correct the gravity potential differences between nodes to obtain real-time gravity potential changes; and an elevation updating module for calculating the elevation changes of each elevation control point based on the conversion relationship between gravity potential and elevation, and updating the elevation datum database.

[0014] As a further technical solution, the multi-source information fusion gravity potential dynamic correction model includes: an optical clock observation submodule, a GNSS deformation monitoring submodule, an absolute gravity monitoring submodule, a tidal correction submodule, an atmospheric load correction submodule, a hydrological load correction submodule, and a crustal deformation monitoring submodule, and calculates the real-time gravity potential change using a weighted least squares estimation method.

[0015] According to one aspect of the present invention, an electronic device is provided, including a processor and a memory, the memory storing a computer program, wherein the processor executes the computer program to implement the aforementioned method for dynamic updating of national elevation benchmarks based on optical clock networks.

[0016] According to one aspect of the present invention, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the aforementioned method for dynamically updating a national elevation datum based on an optical clock network.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses 10 -18The comparison between the optical clock and the fiber optic cable achieves centimeter-level accuracy and eliminates the accumulation of progressive errors. Through real-time synchronous acquisition and fusion correction of multi-source data, the elevation can be continuously and in real time updated, breaking the traditional periodic re-measurement mode and realizing the transformation from a static benchmark to a dynamic benchmark. At the same time, the inclusion of GNSS coordinate change, groundwater change and crustal deformation monitoring data enables the elevation update to reflect the crustal movement and shallow mass migration process in sync. Thus, a real-time dynamic elevation benchmark update system with centimeter-level accuracy, no cumulative error and sustainable operation is established. 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 A flowchart illustrating a method for dynamically updating a national elevation benchmark based on an optical clock network, provided in an embodiment of the present invention; Figure 2 A schematic diagram illustrating the principle of dynamic updating of the national elevation benchmark based on an optical clock network, provided in an embodiment of the present invention; Figure 3 This is a schematic diagram showing the partial node distribution of the dynamic update of the national elevation benchmark based on an optical clock network, provided as an embodiment of the present invention. Detailed Implementation

[0020] In recent years, the frequency stability of high-precision optical clocks has reached 10. -18 The magnitude can be even higher. According to the principle of gravitational frequency shift in general relativity, changes in gravitational potential will cause corresponding changes in optical clock frequency. Therefore, gravitational potential changes can be directly measured using an optical clock network, providing a new technical approach for the dynamic maintenance of the national elevation benchmark. Based on this, this invention provides a method for dynamically updating the national elevation benchmark based on an optical clock network. By constructing an optical clock frequency comparison network covering the elevation origin, first-order leveling points, continuously operating GNSS reference stations, and crustal movement monitoring areas, precise frequency comparison between nodes is achieved using fiber optic time-frequency transmission links to determine gravitational potential differences. Multi-source geodetic observation data is then integrated for dynamic correction, and finally, the real-time dynamic update of the elevation benchmark is achieved based on the conversion relationship between gravitational potential and elevation.

[0021] It should be noted that: 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] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices. The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be decomposed, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0023] 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.

[0024] like Figure 1 As shown in the figure, this embodiment of the invention provides a method for dynamically updating an elevation benchmark based on an optical clock network. The specific steps are as follows.

[0025] Step 1: Deployment of optical clock observation nodes and construction of optical clock frequency comparison network.

[0026] Multiple optical clock observation nodes were deployed at the elevation origin, first-order leveling point, GNSS continuously operating reference station, and crustal movement monitoring area.

[0027] Each node includes: a high-precision optical clock with a frequency stability better than 10. -18The system includes: a femtosecond optical comb for achieving equal-precision up-conversion and down-conversion; an optical frequency transmission device for connecting optical clock frequency signals to fiber optic links for long-distance transmission; a GNSS receiver for continuous tracking and observation of GNSS satellite signals, processing the observation data to obtain the coordinate changes of the station for monitoring crustal deformation; an absolute gravimeter for measuring the absolute gravity changes of the station to provide external constraints and verification for correction results; and an environmental monitoring unit for collecting environmental parameters such as temperature, air pressure, and humidity to compensate for frequency shifts caused by the environment.

[0028] Constructing an optical clock frequency comparison network: A low-loss, low-latency optical fiber network is built to connect the optical clocks of multiple observation stations, enabling efficient transmission of time and frequency signals. Different stations can directly transmit optical clock signals remotely via the optical fiber network. The network topology is designed to ensure reliable signal transmission and time-frequency comparison. This topology allows direct connection, comparison, and elevation transfer between all nodes and reference points.

[0029] Step 2: Fiber optic time-frequency transfer and frequency comparison.

[0030] Using the optical fiber time-frequency transmission link of the optical clock frequency comparison network, frequency comparison is performed on each optical clock node, and the gravitational potential difference between the nodes is measured.

[0031] Adjacent optical clock nodes are connected using fiber optic time-frequency transmission links. Let the optical clock frequencies corresponding to nodes A and B be respectively... and The frequency difference between the two nodes can be expressed as: = - .

[0032] The relative frequency change is as follows: .

[0033] In actual propagation, frequency signals are affected by environmental factors, causing frequency shifts. By analyzing the error characteristics of multi-source frequency shifts and employing optical dual-frequency or tri-frequency comparison techniques, common-mode environmental noise during signal propagation can be eliminated, and gravity-shifted signals can be accurately extracted. .

[0034] Based on the frequency shift relation of general relativity, the frequency difference is converted into a gravitational potential difference: , in, Let be the gravitational potential difference between the two nodes; c is the speed of light in a vacuum. This is the gravitational frequency shift.

[0035] like Figure 2The diagram shown illustrates remote fiber optic clock comparison. Optical clock P and optical clock Q are connected via an optical fiber link. An optical amplifier (EDFA) is mounted on the fiber optic link, and a reflector is also installed at the Q end to enable round-trip signal transmission. In actual operation, optical clock P transmits a frequency to optical clock Q. The signal becomes Q after it arrives. After being reflected back to P at point Q, the signal becomes... Simultaneously, optical clock Q transmits frequency to optical clock P. When the signal reaches P, the signal is ,in and It is the frequency shift generated during signal propagation. Through this three-frequency comparison link, common-mode noise in the signal propagation process can be eliminated and the gravity frequency shift signal can be extracted.

[0036] Step 3: Acquire multi-source observation data synchronously.

[0037] Simultaneously acquired data include: GNSS coordinate changes, absolute gravity changes, tidal model data, atmospheric pressure data, groundwater variation data, and crustal deformation monitoring data. These observational data are then integrated to construct a dynamic gravity potential correction model, which includes multi-source error correction data.

[0038] Step 4: Dynamic correction model of gravity potential based on multi-source information fusion.

[0039] A multi-source information fusion gravity potential dynamic correction model is established. The crustal deformation correction is calculated based on the GNSS coordinate change and crustal deformation monitoring data. The tidal correction, atmospheric load correction, and groundwater change correction are calculated based on the tidal model data, atmospheric pressure data, and groundwater change data, respectively. The correction results are constrained and verified using the absolute gravity change to obtain the real-time gravity potential change.

[0040] The multi-source information fusion gravity potential dynamic correction model includes: an optical clock observation submodule, a GNSS deformation monitoring submodule, an absolute gravity monitoring submodule, a tidal correction submodule, an atmospheric load correction submodule, a hydrological load correction submodule, and a crustal deformation monitoring submodule. The real-time gravity potential change is calculated using the weighted least squares estimation method.

[0041] The real-time change in gravitational potential is expressed as: , in: The difference in gravitational potential between nodes; This is the tidal correction amount; This is the atmospheric load correction amount; This is a correction for changes in groundwater levels. This is the correction amount for crustal deformation.

[0042] Step 5, Dynamically update elevation values

[0043] Based on the real-time changes in gravity potential and the conversion relationship between gravity potential and elevation, the elevation values ​​of each elevation control point are dynamically updated. This embodiment establishes a dynamic update mechanism to ensure that the elevation benchmark can reflect changes caused by natural phenomena such as crustal movement in real time, thereby improving the timeliness and reliability of the benchmark.

[0044] The dynamic updating of the elevation values ​​of each elevation control point adopts a dynamic gravity potential-elevation conversion model. , in, For the updated elevation, For reference, the initial elevation at that time, This represents the dynamic change in gravitational potential. Let ε(t) be the local gravitational acceleration, and ε(t) be the environmental compensation term.

[0045] The calculated real-time elevation values ​​are written into the elevation benchmark database, forming a real-time elevation results database, a historical change database, and a dynamic correction database.

[0046] Based on the same inventive concept, this invention also provides a dynamic update system for a national elevation benchmark based on an optical clock network. The system includes an optical clock observation module, an optical fiber time and frequency transmission module, a frequency comparison module, a gravity potential calculation module, a multi-source data fusion module, and an elevation update module.

[0047] The optical clock observation module is deployed at the elevation origin, first-order leveling points, continuously operating GNSS reference stations, and crustal movement monitoring areas to provide frequency references and time-frequency signals. Each observation node includes a high-precision optical clock, femtosecond optical comb, optical frequency transmission equipment, GNSS receiver, absolute gravimeter, and environmental monitoring unit.

[0048] The fiber optic time and frequency transmission module connects each optical clock observation node through a low-loss, low-latency fiber optic link to achieve frequency synchronization and frequency comparison between the nodes.

[0049] The frequency comparison module is used to obtain the frequency difference observations between each optical clock node.

[0050] The gravity potential calculation module is used to convert the frequency difference observations into inter-node gravity potential differences based on the principle of gravity frequency shift in general relativity.

[0051] The multi-source data fusion module integrates GNSS coordinate changes, absolute gravity changes, tidal model data, atmospheric pressure data, groundwater change data, and crustal deformation monitoring data to establish a dynamic gravity potential correction model based on multi-source information fusion. This model dynamically corrects the gravity potential differences between the nodes to obtain real-time gravity potential changes. The dynamic gravity potential correction model includes an optical clock observation submodule, a GNSS deformation monitoring submodule, an absolute gravity monitoring submodule, a tidal correction submodule, an atmospheric load correction submodule, a hydrological load correction submodule, and a crustal deformation monitoring submodule. The outputs of each submodule are jointly processed using weighted least squares estimation to calculate the real-time gravity potential changes.

[0052] The elevation update module is used to calculate the elevation change of each elevation control point based on the conversion relationship between gravity potential and elevation, and to update the elevation datum database.

[0053] This system is used to execute the steps of the above method embodiments. Its specific implementation principle and workflow are the same as those of the aforementioned method embodiments, and will not be repeated here.

[0054] This invention also provides an electronic device, including a processor and a memory, wherein the memory stores a computer program. When the processor executes the computer program, it implements the dynamic update method for the national elevation benchmark based on an optical clock network as described in the foregoing method embodiments.

[0055] The electronic device may be a server, computer, embedded system, or other device with data processing capabilities. The memory may be a high-speed random access memory or a non-volatile memory, such as a hard disk, read-only memory, programmable read-only memory, erasable programmable read-only memory, flash memory, etc. The processor may be a central processing unit, microprocessor, digital signal processor, programmable logic controller, or other processing element with data processing capabilities.

[0056] When the computer program is executed by the processor, it performs at least the following steps: Deploying multiple optical clock observation nodes at the elevation origin, first-order leveling points, GNSS continuously operating reference stations, and the crustal movement monitoring area, and constructing an optical clock frequency comparison network; using fiber optic time-frequency transmission links to compare the frequencies of each optical clock node to determine the gravity potential difference between nodes; synchronously acquiring GNSS coordinate changes, absolute gravity changes, tidal model data, atmospheric pressure data, groundwater change data, and crustal deformation monitoring data; establishing a multi-source information fusion gravity potential dynamic correction model, calculating corresponding correction amounts based on various types of data, using absolute gravity changes to constrain and verify the correction results, and obtaining real-time gravity potential changes; dynamically updating the elevation values ​​of each elevation control point based on the real-time gravity potential changes and the conversion relationship between gravity potential and elevation.

[0057] In practical applications, this electronic device can be deployed in a data processing center to centrally process and calculate the time and frequency data collected by each node in the optical clock frequency comparison network and the synchronously acquired multi-source observation data.

[0058] This invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the dynamic update method for national elevation benchmarks based on optical clock networks as described in the foregoing method embodiments.

[0059] The computer-readable storage medium can be any tangible medium capable of storing computer programs, including but not limited to: disk storage devices (such as hard disks, floppy disks, magnetic tapes), optical disks (such as CD-ROMs, DVDs), semiconductor storage devices (such as read-only memory, random access memory, flash memory, USB storage devices), and other forms of fixed or removable storage media.

[0060] The computer program can be written using any combination of one or more programming languages, including object-oriented programming languages ​​and conventional procedural programming languages. The computer program can be stored on a computer-readable storage medium and can also be transmitted and distributed via a network or other communication medium.

[0061] This computer-readable storage medium can exist independently of the electronic device, serving as a carrier for software products for sale or use; alternatively, it can be integrated into the electronic device as an internal storage component. Users can implement the dynamic elevation benchmark update method provided by this invention by loading the computer program from the storage medium into the electronic device and having it executed by the processor.

[0062] The specific implementation principle of this method is the same as that of the aforementioned method embodiments, and will not be repeated here.

[0063] As a preferred embodiment, such as Figure 3 As shown, a master optical clock node is deployed at the national geodetic datum, and regional optical clock nodes are deployed in several major cities. The nodes are connected by a fiber optic network, and the optical clock accuracy is better than 10⁻⁶. -18 At a massive scale, each station is equipped with a femtosecond optical comb for frequency up-conversion and down-conversion. When different stations perform dual-frequency or tri-frequency optical comparisons with the national leveling datum, the gravity difference and elevation difference between the leveling datum and the deployed stations can be obtained in real time. Through joint measurements of multiple important leveling points and the leveling datum across the country, the elevation data of each node can be updated in real time, ultimately achieving dynamic maintenance of the elevation benchmark nationwide.

[0064] The experimental procedure in this embodiment includes the following steps: a. Atomic clock setup: High-precision optical clocks are placed at the leveling datum and multiple stations, with long-term stability better than 10. -18 At the scale of [unclear], each site is equipped with a femtosecond optical comb to achieve frequency up-conversion and down-conversion.

[0065] b. Set up signal amplifiers on the fiber optic links from the leveling origin station to other stations, and use optical frequency dual-frequency or tri-frequency comparison technology to achieve remote optical clock comparison at the kilometer level, eliminate frequency shift during signal propagation, and extract gravity frequency shift signals.

[0066] c. Data Acquisition: Configure data recording parameters on the data acquisition device, such as sampling frequency and data format. Start the data acquisition program; the system records time-frequency comparison data from the remote optical clock and the local optical clock in real time. Record the acquired data using local storage devices, preprocess the raw data, and filter and remove unqualified data.

[0067] d. Data processing: Using the data collected by fiber optic dual-frequency or tri-frequency comparison technology, the gravitational potential difference between the leveling origin and each node is calculated based on the principle of general relativity. Using a higher-order gravitational potential and altitude conversion model, the real-time change data of the altitude difference between the leveling origin and different nodes is obtained, and the elevation data of each node is updated accordingly.

[0068] Through this embodiment, the gravity difference and elevation difference at different nodes can be obtained in real time, and the accuracy of the dynamically updated elevation benchmark reaches the centimeter level.

[0069] In summary, this invention proposes a method and system for dynamically updating a national elevation datum based on an optical clock network. This method constructs an optical clock frequency comparison network by deploying high-precision optical clock nodes at the elevation origin, first-order leveling points, continuously operating GNSS reference stations, and crustal movement monitoring areas. Frequency comparison between different optical clock nodes is achieved using fiber optic time-frequency transmission links, and the gravity potential difference between nodes is measured. Simultaneously, GNSS coordinate changes, absolute gravity changes, tidal model data, atmospheric pressure data, groundwater change data, and crustal deformation monitoring data are acquired to establish a multi-source information fusion-based dynamic gravity potential correction model. The elevation values ​​of each elevation control point are dynamically updated based on the real-time acquired gravity potential changes, thus achieving real-time dynamic updating of the national elevation datum.

[0070] This method utilizes high-precision optical clocks, fiber optic links, and dual- or tri-frequency comparison technology to achieve real-time measurement and updating of optical clocks, gravity potential differences, and elevations at remote sites. It significantly overcomes the shortcomings of traditional elevation measurements, such as error accumulation, low accuracy, high measurement costs, and difficulty in real-time elevation data updates, enabling direct elevation transfer between the elevation origin and any elevation control point. This scheme not only provides a new approach to the unification of global elevation benchmarks but also lays the technical foundation for future gravity potential determination and elevation benchmark integration. This invention can continuously monitor changes in elevation benchmarks, promptly reflecting the impact of crustal movement, land subsidence, groundwater changes, and tidal effects on elevation benchmarks. It can be widely applied in elevation benchmark maintenance, major engineering construction, natural disaster monitoring, and geodynamics research.

[0071] 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 dynamically updating a national elevation datum based on an optical clock network, characterized in that, include: Multiple optical clock observation nodes were deployed at the elevation origin, first-order leveling point, GNSS continuously operating reference station and crustal movement monitoring area to construct an optical clock frequency comparison network. Using the optical fiber time-frequency transmission link of the optical clock frequency comparison network, frequency comparison is performed on each optical clock node, and the gravitational potential difference between nodes is measured. Simultaneously acquire GNSS coordinate changes, absolute gravity changes, tidal model data, atmospheric pressure data, groundwater change data, and crustal deformation monitoring data; A multi-source information fusion gravity potential dynamic correction model is established. The crustal deformation correction is calculated based on the GNSS coordinate change and crustal deformation monitoring data. The tidal correction, atmospheric load correction, and groundwater change correction are calculated based on the tidal model data, atmospheric pressure data, and groundwater change data, respectively. The correction results are constrained and verified using the absolute gravity change to obtain the real-time gravity potential change. Based on the real-time change in gravity potential, and according to the conversion relationship between gravity potential and elevation, the elevation values ​​of each elevation control point are dynamically updated.

2. The method for dynamic updating of national elevation benchmarks based on optical clock networks according to claim 1, characterized in that, The optical clock node has a frequency stability better than 10. -18 The optical atomic clock is of the order of magnitude, with each node equipped with a femtosecond optical comb to achieve up-conversion and down-conversion with equal precision.

3. The method for dynamic updating of national elevation benchmarks based on optical clock networks according to claim 1, characterized in that, Using the optical fiber time-frequency transmission link of the optical clock frequency comparison network, frequency comparison is performed on each optical clock node, including: using optical dual-frequency or tri-frequency comparison technology to eliminate common-mode environmental noise during signal propagation and extract gravity frequency shift signals.

4. The method for dynamic updating of national elevation benchmarks based on optical clock networks according to claim 1, characterized in that, The multi-source information fusion gravity potential dynamic correction model includes: an optical clock observation submodule, a GNSS deformation monitoring submodule, an absolute gravity monitoring submodule, a tidal correction submodule, an atmospheric load correction submodule, a hydrological load correction submodule, and a crustal deformation monitoring submodule. The real-time gravity potential change is calculated using the weighted least squares estimation method.

5. The method for dynamic updating of national elevation benchmarks based on optical clock networks according to claim 1, characterized in that, The real-time change in gravitational potential is expressed as: ， in, The difference in gravitational potential between nodes; This is the tidal correction amount; This is the atmospheric load correction amount; This is a correction for changes in groundwater levels. This is a correction for crustal deformation; the absolute gravity change is used to adjust for... The calculation results are subjected to external constraints and accuracy verification.

6. The method for dynamic updating of national elevation benchmarks based on optical clock networks according to claim 1, characterized in that, The dynamic updating of the elevation values ​​of each elevation control point adopts a dynamic gravity potential-elevation conversion model. ， in, For the updated elevation, This is the initial elevation. This represents the dynamic change in gravitational potential. Let ε(t) be the local gravitational acceleration, and let ε(t) be the environmental compensation term.

7. A dynamic updating system for a national elevation datum based on an optical clock network, characterized in that, include: The optical clock observation module is deployed at the elevation origin, first-order leveling points, GNSS continuously operating reference stations, and crustal movement monitoring areas to provide frequency references and time-frequency signals. The fiber optic time and frequency transmission module is used to connect various optical clock observation nodes to achieve frequency synchronization and frequency comparison between nodes; The frequency comparison module is used to obtain the frequency difference observations between each optical clock node; The gravity potential calculation module is used to convert the frequency difference observations into inter-node gravity potential differences based on the principle of gravity frequency shift in general relativity. The multi-source data fusion module is used to fuse GNSS coordinate changes, absolute gravity changes, tidal model data, atmospheric pressure data, groundwater change data, and crustal deformation monitoring data to establish a dynamic gravity potential correction model for multi-source information fusion and dynamically correct the gravity potential difference between the nodes to obtain real-time gravity potential changes. The elevation update module is used to calculate the elevation change of each elevation control point based on the conversion relationship between gravity potential and elevation, and to update the elevation benchmark database.

8. The national elevation datum dynamic update system based on optical clock network according to claim 7, characterized in that, The multi-source information fusion gravity potential dynamic correction model includes: an optical clock observation submodule, a GNSS deformation monitoring submodule, an absolute gravity monitoring submodule, a tidal correction submodule, an atmospheric load correction submodule, a hydrological load correction submodule, and a crustal deformation monitoring submodule. The real-time gravity potential change is calculated using the weighted least squares estimation method.

9. An electronic device comprising a processor and a memory, the memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the method for dynamic updating of national elevation benchmarks based on optical clock networks as described in any one of claims 1 to 6.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for dynamic updating of the national elevation datum based on an optical clock network as described in any one of claims 1 to 6.

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