Method and system for precise satellite-based time transfer based on integration of beidou / galileo systems

Abstract

The application relates to a Beidou / Galileo system fusion-based satellite-based precise timing method and system. Observation data, broadcast ephemeris data and correction numbers broadcast by a Beidou three-satellite system and a Galileo satellite system are respectively received by a receiver, two different systems are fused for timing, system clock differences between the two satellite systems are respectively taken as constants, white noises and random walks for construction of an estimation model, a PPP fusion model of the two satellite systems is constructed, each estimation model is brought into the fusion model for calculation, the estimation model corresponding to the best timing precision is taken as an optimal estimation model for correction of the system clock difference, other satellite data is corrected, receiver clock difference parameters are obtained, the parameters are used for clock taming, and satellite-based precise timing is completed. The method has higher timing precision and a wider application range.

Description

Technical Field

[0001] This application relates to the field of navigation satellite timing technology, and in particular to a satellite-based precision timing method and system based on the fusion of the BeiDou / Galileo systems. Background Technology

[0002] Time information plays an indispensable role in smart cities, smart living, 5G, and other fields. Due to the all-weather, real-time, and high-precision characteristics of satellite navigation systems, satellite time synchronization is widely used in various industries.

[0003] With the rapid development of technology, the accuracy of traditional satellite time synchronization (20-50ns) is gradually becoming insufficient to meet the needs of high-tech industries. Currently, high-precision satellite time synchronization technologies mainly include common-view satellite time synchronization, all-view satellite time synchronization, and precise point positioning (PPP) time synchronization. Among these methods, PPP time synchronization has the highest accuracy, but all three methods rely on networks to achieve communication and data exchange, making them difficult to apply to time service needs in various environments.

[0004] In general, traditional satellite timing technology is insufficient to meet the needs of advanced technologies in different situations. Summary of the Invention

[0005] Therefore, it is necessary to provide a satellite-based precision timing method and system based on the fusion of the BeiDou / Galileo system, which has higher timing accuracy and wider application range, to address the above-mentioned technical problems.

[0006] A satellite-based precision time synchronization method based on the fusion of the BeiDou / Galileo systems, the method comprising:

[0007] Acquire satellite observation data, broadcast ephemeris data, and service corrections transmitted by the BeiDou-3 satellite system and the Galileo satellite system, wherein the service corrections include PPP-B2b corrections and HAS corrections transmitted by the two satellite systems respectively;

[0008] The system clock error between the two satellite systems is modeled as a constant, white noise, and random walk, respectively, to obtain the corresponding estimation model;

[0009] Construct a PPP fusion model for two satellite systems, and input each of the estimated models into the PPP fusion model to calculate the result of the PPP fusion model. The estimated model with the highest timing accuracy is taken as the optimal estimated model.

[0010] The satellite observation data, broadcast ephemeris data, and system clock bias transmitted by each satellite system are corrected to obtain the receiver clock bias parameters. The optimal estimation model is used when correcting the system clock bias.

[0011] Clock discipline is performed using the receiver clock bias parameters to achieve satellite-based precision time synchronization.

[0012] In one embodiment, the PPP fusion model adopts:

[0013]

[0014] In the above formula, the subscript IF represents the combined observation of the destrophic layer, the subscript r represents the receiver, the superscript C represents the BeiDou-3 satellite system, the superscript E represents the Galileo satellite system, P represents the pseudorange observation, and ρ represents the satellite-to-ground distance. This indicates that the receiver clock bias, which incorporates pseudorange hardware delay, is included in the satellite observation equations of the BeiDou-3 system. The ISB represents the system bias in the Galileo system's satellite observation equations relative to the BeiDou-3 system's satellite observation equations, and λ represents the satellite clock bias. IF Indicates the ionospheric delay, T represents the tropospheric delay. The floating-point unambiguity parameter is represented by ε, and ξ represents the pseudorange and carrier noise, respectively.

[0015] In one embodiment, the combined observations of the desiccant are used by the BeiDou-3 satellite system, which uses a combination of B1I and B3I, and by the Galileo satellite system, which uses a combination of E1 and E5a.

[0016] In one embodiment, the step of correcting the satellite observation data, broadcast ephemeris data, and system clock bias transmitted by each satellite system to obtain receiver clock bias parameters includes:

[0017] Multiple error equations are constructed for the corresponding data using either model or parameter estimation methods.

[0018] The Kalman filtering method is used to solve for each of the aforementioned error methods to obtain the receiver clock error parameters.

[0019] In one embodiment, when correcting for orbital and clock errors in satellite observation data and broadcast ephemeris data transmitted by various satellite systems:

[0020] The data transmitted by the two satellite systems are analyzed separately, and the orbital data and clock bias data of the two satellite systems are calculated using the analyzed broadcast ephemeris data.

[0021] The PPP-B2b correction and HAS correction are combined with the orbital data and clock bias data of the corresponding satellite system to obtain the real-time precise orbital and clock bias data of the corresponding satellite system.

[0022] The orbital and clock errors in the corresponding satellite systems are corrected using the real-time precise orbit and clock error data, respectively.

[0023] In one embodiment, the following formula is used to calculate the real-time precise orbit data of the satellite system:

[0024]

[0025] In the above formula, X represents real-time precision orbit data, X brdc This indicates the satellite coordinates calculated based on broadcast ephemeris data, (e r ,e a ,e c ) represents the rotation matrix in the meridional, normal, and tangential directions; ΔO represents the PPP-B2b correction or HAS correction; r and These represent the satellite's velocity and position vectors, respectively.

[0026] In one embodiment, the following formula is used to calculate the real-time precision clock bias data of the satellite system:

[0027]

[0028] In the above formula, T represents the real-time precision clock difference data, T brd This represents the satellite clock bias data calculated based on broadcast ephemeris data; ΔT represents the PPP-B2b correction or HAS correction; and c represents the speed of light.

[0029] In one embodiment, when correcting satellite observation data and broadcast ephemeris data transmitted by each satellite system:

[0030] Models are used to correct for satellite antenna phase center error, relativistic effect error, atmospheric error, receiver antenna phase center error, and tidal error.

[0031] Tropospheric moisture component error, receiver clock error, receiver coordinate error, ambiguity error, and tropospheric moisture component error are corrected using parameter estimation methods;

[0032] Specifically, the receiver coordinate error is estimated using static parameters, the receiver clock error is estimated using white noise, the ambiguity error is estimated using a constant parameter, and the tropospheric wet component error is estimated using a random walk parameter.

[0033] A satellite-based precision timing device based on the fusion of the BeiDou / Galileo systems, the device comprising:

[0034] The satellite system data acquisition module is used to acquire satellite observation data, broadcast ephemeris data and service correction data sent by the BeiDou-3 satellite system and the Galileo satellite system, wherein the service correction data includes PPP-B2b correction data and HAS correction data sent by the two satellite systems respectively.

[0035] The system clock error estimation model building module is used to model the system clock error between two satellite systems as a constant, white noise, and random walk, respectively, to obtain the corresponding estimation model.

[0036] The optimal estimation model selection module is used to construct a PPP fusion model for two satellite systems, and to input each of the estimation models into the PPP fusion model to calculate the result of the PPP fusion model, and select the estimation model with the highest timing accuracy as the optimal estimation model.

[0037] The receiver clock bias parameter acquisition module is used to correct the satellite observation data, broadcast ephemeris data and system clock bias transmitted by each satellite system to obtain the receiver clock bias parameters. The optimal estimation model is used when correcting the system clock bias.

[0038] The satellite-based precision time synchronization module is used to perform clock discipline using the receiver clock difference parameters in order to complete satellite-based precision time synchronization.

[0039] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps:

[0040] Acquire satellite observation data, broadcast ephemeris data, and service corrections transmitted by the BeiDou-3 satellite system and the Galileo satellite system, wherein the service corrections include PPP-B2b corrections and HAS corrections transmitted by the two satellite systems respectively;

[0041] The system clock error between the two satellite systems is modeled as a constant, white noise, and random walk, respectively, to obtain the corresponding estimation model;

[0042] Construct a PPP fusion model for two satellite systems, and input each of the estimated models into the PPP fusion model to calculate the result of the PPP fusion model. The estimated model with the highest timing accuracy is taken as the optimal estimated model.

[0043] The satellite observation data, broadcast ephemeris data, and system clock bias transmitted by each satellite system are corrected to obtain the receiver clock bias parameters. The optimal estimation model is used when correcting the system clock bias.

[0044] Clock discipline is performed using the receiver clock bias parameters to achieve satellite-based precision time synchronization.

[0045] A computer-readable storage medium having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0046] Acquire satellite observation data, broadcast ephemeris data, and service corrections transmitted by the BeiDou-3 satellite system and the Galileo satellite system, wherein the service corrections include PPP-B2b corrections and HAS corrections transmitted by the two satellite systems respectively;

[0047] The system clock error between the two satellite systems is modeled as a constant, white noise, and random walk, respectively, to obtain the corresponding estimation model;

[0048] Construct a PPP fusion model for two satellite systems, and input each of the estimated models into the PPP fusion model to calculate the result of the PPP fusion model. The estimated model with the highest timing accuracy is taken as the optimal estimated model.

[0049] The satellite observation data, broadcast ephemeris data, and system clock bias transmitted by each satellite system are corrected to obtain the receiver clock bias parameters. The optimal estimation model is used when correcting the system clock bias.

[0050] Clock discipline is performed using the receiver clock bias parameters to achieve satellite-based precision time synchronization.

[0051] A satellite-based precision timing system based on Galileo system fusion, wherein the above-mentioned satellite-based precision timing method is implemented in the satellite-based precision timing system, and the satellite-based precision timing system includes: a GNSS receiving unit, a calculation unit, a discipline unit, and a crystal oscillator unit;

[0052] The GNSS receiving unit is used to acquire satellite observation data, broadcast ephemeris data and service corrections sent by the BeiDou-3 satellite system and the Galileo satellite system, wherein the service corrections include PPP-B2b corrections and HAS corrections sent by the two satellite systems respectively, and sends the satellite observation data, broadcast ephemeris data and service corrections to the solving unit.

[0053] The calculation unit is used to model the system clock error between the two satellite systems as a constant, white noise, and random walk, respectively, to obtain the corresponding estimation models, construct the PPP fusion model of the two satellite systems, and input each of the estimation models into the PPP fusion model to calculate the result of the PPP fusion model. The estimation model with the highest timing accuracy is taken as the optimal estimation model. The satellite observation data, broadcast ephemeris data, and system clock error transmitted by each satellite system are corrected to obtain the receiver clock error parameters. When correcting the system clock error, the optimal estimation model is used, and the receiver clock error parameters are sent to the discipline unit.

[0054] The discipline unit is used to generate crystal oscillator discipline information according to the receiver clock difference parameters, and send the crystal oscillator discipline information to the crystal oscillator unit;

[0055] The crystal oscillator unit is used to perform discipline based on the crystal oscillator discipline information and output a 10MHz signal to the GNSS receiver, so that the GNSS receiver outputs a 1PPS signal and UTC information based on the 10MHz signal input signal.

[0056] The aforementioned satellite-based precise time synchronization method and system based on the fusion of the BeiDou / Galileo systems involves a receiver receiving observation data, broadcast ephemeris data, and corrections broadcast from both the BeiDou-3 and Galileo satellite systems. The two systems are then fused for time synchronization. The system clock biases between the two satellite systems are used as constants, white noise, and random walks, respectively, to construct estimation models. Simultaneously, a PPP fusion model for both satellite systems is constructed. Each estimation model is then incorporated into the fusion model for calculation. The estimation model with the best timing accuracy is selected as the optimal estimation model to correct the system clock bias and further correct other satellite data, yielding the receiver clock bias parameters. These parameters are then used for clock discipline to achieve satellite-based precise time synchronization. This method offers higher timing accuracy and a wider range of applications. Attached Figure Description

[0057] Figure 1 This is a flowchart illustrating a satellite-based precision time synchronization method based on the fusion of the BeiDou and Galileo systems in one embodiment.

[0058] Figure 2 This is a schematic diagram of the process framework of a satellite-based precision time synchronization method based on the fusion of the BeiDou / Galileo systems in one embodiment;

[0059] Figure 3 This is a schematic diagram of the process framework for a satellite-based precision time synchronization method based on the fusion of the BeiDou / Galileo systems in another embodiment;

[0060] Figure 4This is a schematic diagram comparing the results of time synchronization using this method and the traditional method in one embodiment;

[0061] Figure 5 This is a structural block diagram of a satellite-based precision timing device based on the fusion of the BeiDou and Galileo systems in one embodiment.

[0062] Figure 6 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0064] like Figure 1 As shown, a satellite-based precise timing method based on the fusion of the BeiDou / Galileo systems is provided, including the following steps:

[0065] Step S100: Obtain satellite observation data, broadcast ephemeris data and service corrections sent by the BeiDou-3 satellite system and the Galileo satellite system, wherein the service corrections include PPP-B2b corrections and HAS corrections sent by the two satellite systems respectively.

[0066] Step S110: The system clock difference between the two satellite systems is modeled as a constant, white noise, and random walk, respectively, to obtain the corresponding estimation model;

[0067] Step S120: Construct a PPP fusion model for the two satellite systems, and input each estimation model into the PPP fusion model to calculate the result of the PPP fusion model. The estimation model with the highest timing accuracy is taken as the optimal estimation model.

[0068] Step S130: Correct the satellite observation data, broadcast ephemeris data and system clock bias sent by each satellite system to obtain receiver clock bias parameters. The optimal estimation model is used when correcting the system clock bias.

[0069] Step S140: Clock discipline is performed using receiver clock bias parameters to complete satellite-based precision time synchronization.

[0070] In this embodiment, to address the issues of low accuracy in traditional satellite timing methods and poor reliability due to reliance on network data transmission in high-precision satellite timing methods, a satellite-based precision timing method is proposed that integrates the BeiDou-3 and Galileo satellite systems. Specifically, by utilizing the Precise Point Positioning Service (PPP-B2b) of the BeiDou-3 (BDS-3) satellite and the High Accuracy Service (HAS) of the Galileo satellite, high-precision timing can be achieved in global environments without network coverage.

[0071] In step S100, satellite observation data refers to information collected from satellite systems regarding the Earth's surface, atmosphere, oceans, etc. This data is typically recorded digitally and covers multiple spectral ranges. Broadcast ephemeris data, on the other hand, is data containing satellite orbit information and clock correction parameters. This data is transmitted from the satellite via radio signals and broadcast for use by receivers.

[0072] Correction services are a technique used to improve the positioning accuracy of the Global Positioning System (GPS) or other satellite navigation systems. These corrections are calibration data generated by ground stations or other means, which can correct errors in navigation signals, thereby providing more accurate position, velocity, and clock information.

[0073] Because positioning system signals can be affected by various factors during propagation, such as atmospheric delay, ionospheric effects, and satellite orbital errors, the goal of service corrections is to monitor these errors, generate correction data on the ground, and send it to the receiver so that the receiver can correct the received navigation information. In this application, both PPP-B2b corrections and HAS corrections are used to correct orbital and clock errors.

[0074] BDS-3PPP-B2b and Galileo HAS broadcast correction values ​​via B2b and E6 signals respectively, and can achieve high-precision positioning and timing by directly receiving the corresponding signals, without the need for network communication, making them more universal.

[0075] After receiving data from the two satellite systems, the corresponding ICD (Interface Control Document) files are used to parse the satellite data. ICD files are typically very detailed and complex, covering many different technical details. In the ICD files for BeiDou and Galileo, the information regarding observations, broadcast ephemeris, PPP-B2b service corrections, and HAS service corrections is even more detailed and complex.

[0076] In this embodiment, signals from two different satellite systems are used to achieve high-precision time synchronization. Since different satellite systems may be affected by different errors, clock bias compensation between the systems is necessary. In step S110, the system clock bias between the two satellite systems is modeled as a constant, white noise, and random walk, respectively, to obtain corresponding estimation models. Then, the PPP fusion model constructed in step S120 is used to select from the three estimation models, choosing the most suitable model for estimating the system clock bias. This effectively improves calibration accuracy.

[0077] In step S120, a PPP fusion model of the BeiDou-3 satellite system and the Galileo satellite system is first constructed. In this embodiment, an ionospheric-free combined model is used to eliminate ionospheric errors. Therefore, the BDS-3 / Galileo fused ionospheric-free PPP timing model can be expressed as:

[0078]

[0079] In formula (1), the subscript IF represents the combined observation of the desiccation layer, the subscript r represents the receiver, the superscript C represents the BeiDou-3 satellite system, the superscript E represents the Galileo satellite system, P represents the pseudorange observation, and ρ represents the satellite-to-ground distance. This indicates that the receiver clock bias, which incorporates pseudorange hardware delay, is included in the satellite observation equations of the BeiDou-3 system. The ISB represents the system bias in the Galileo system's satellite observation equations relative to the BeiDou-3 system's satellite observation equations, and λ represents the satellite clock bias. IF Indicates the ionospheric delay, T represents the tropospheric delay. The floating-point unambiguity parameter is represented by ε, and ξ represents the pseudorange and carrier noise, respectively.

[0080] In one embodiment, in the combined observations of the desiccation layer, the BeiDou-3 satellite system uses a combination of B1I and B3I observations, and the Galileo satellite system uses a combination of E1 and E5a observations.

[0081] After constructing the PPP fusion model, the three estimation models are respectively input into the model to calculate the timing results. During the calculation process, the PPP-B2b correction and HAS correction are also stored in a file and then input into the PPP fusion model for calculation. The estimation model with the highest timing accuracy in the calculation results is used to correct the system clock bias (IBS).

[0082] In step S130, the satellite observation data, broadcast ephemeris data and system clock bias transmitted by each satellite system are corrected to obtain the receiver clock bias parameters. This includes constructing multiple error equations for the corresponding data errors using model or parameter estimation methods, solving each error method using the Kalman filtering method, and obtaining the receiver clock bias parameters.

[0083] In this embodiment, when correcting the orbital and clock errors in the satellite observation data and broadcast ephemeris data transmitted by each satellite system: the orbital and clock error data of the two satellite systems are calculated using the parsed broadcast ephemeris data. The PPP-B2b correction and HAS correction are then merged with the orbital and clock error data of the corresponding satellite system to obtain the real-time precise orbit and clock error data of the corresponding satellite system. The orbital and clock error in the corresponding satellite system are then corrected using the real-time precise orbit and clock error data.

[0084] In this embodiment, the following formula is used to calculate the real-time precise orbit data of the satellite system:

[0085]

[0086] In formula (2) above, X represents real-time precision orbit data, X brdc This indicates the satellite coordinates calculated based on broadcast ephemeris data, (e r ,e a ,e c ) represents the rotation matrix in the meridional, normal, and tangential directions; ΔO represents the PPP-B2b correction or HAS correction; r and These represent the satellite's velocity and position vectors, respectively.

[0087] In this embodiment, the following formula is used to calculate the real-time precision clock bias data of the satellite system:

[0088]

[0089] In formula (3), T represents the real-time precision clock difference data, T brd This represents the satellite clock bias data calculated based on broadcast ephemeris data; ΔT represents the PPP-B2b correction or HAS correction; and c represents the speed of light.

[0090] In this embodiment, when correcting the satellite observation data and broadcast ephemeris data transmitted by each satellite system: satellite antenna phase center error, relativistic effect error, atmospheric error, receiver antenna phase center error, and tidal error are corrected using models. Tropospheric moisture component error, receiver clock error, receiver coordinate error, ambiguity error, and tropospheric moisture component error are corrected using parameter estimation methods. Specifically, receiver coordinate error is estimated using static parameters, receiver clock error is estimated using white noise, ambiguity error is estimated using a constant parameter, and tropospheric moisture component error is estimated using random walk parameters.

[0091] In step S140, the internal clock is first tamed using the obtained receiver clock bias parameters. Specifically, this process includes: preprocessing the real-time receiver clock bias parameters using a sliding window mean-of-sight method; then estimating the clock driving parameters using the preprocessed receiver clock bias parameters, employing the following formula:

[0092]

[0093] In formula (4), A represents the clock error data, B0 represents the initial frequency deviation of the crystal oscillator, and A0 represents the initial time deviation of the rubidium clock. α represents the random noise error of the crystal oscillator, and α represents the frequency drift or frequency aging coefficient of the crystal oscillator.

[0094] Next, direct digital frequency synthesis technology is used to control the signal phase and frequency, and finally the 10MHz clock signal is output to the receiver to tame the internal clock of the receiver.

[0095] At the same time, the clock-disciplined receiver outputs a 1PPS signal and UTC time information.

[0096] To make this precise timekeeping method more intuitive and easier to understand, you can also refer to, for example... Figure 2 and Figure 3 This method needs to be understood. Furthermore, to demonstrate its effectiveness, the receiver clock bias calculated using this method is compared with that calculated using traditional satellite timing methods. Figure 4 As shown, it can be seen that the accuracy of the time synchronization results calculated using this method is significantly improved.

[0097] In this embodiment, a satellite-based precision timing system based on Galileo system fusion is also provided. The satellite-based precision timing system implements the above-mentioned satellite-based precision timing method. The satellite-based precision timing system specifically includes: a GNSS receiving unit, a calculation unit, a discipline unit, and a crystal oscillator unit.

[0098] The GNSS receiving unit is used to acquire satellite observation data, broadcast ephemeris data, and service corrections sent by the BeiDou-3 satellite system and the Galileo satellite system. The service corrections include PPP-B2b corrections and HAS corrections sent by the two satellite systems respectively. The GNSS receiving unit then sends the satellite observation data, broadcast ephemeris data, and service corrections to the calculation unit.

[0099] The solution unit then models the system clock bias between the two satellite systems as a constant, white noise, and random walk, respectively, to obtain the corresponding estimation models. At the same time, a PPP fusion model of the two satellite systems is constructed, and each estimation model is substituted into the PPP fusion model to calculate the result of the PPP fusion model. The estimation model with the highest timing accuracy is taken as the optimal estimation model. The satellite observation data, broadcast ephemeris data, and system clock bias transmitted by each satellite system are corrected to obtain the receiver clock bias parameters. Among them, the optimal estimation model is used when correcting the system clock bias, and the receiver clock bias parameters are sent to the discipline unit.

[0100] In this embodiment, when the calculation unit processes the satellite data sent by the GNSS receiving unit to obtain the receiver clock error parameters, the PPP engine is used to perform the calculation in real time.

[0101] The discipline unit is used to generate crystal oscillator discipline information based on the receiver clock difference parameters and send the crystal oscillator discipline information to the crystal oscillator unit.

[0102] Finally, the crystal oscillator unit performs discipline based on the crystal oscillator discipline information and outputs a 10MHz signal to the GNSS receiver, so that the GNSS receiver outputs a 1PPS signal and UTC information based on the 10MHz signal input signal.

[0103] In this embodiment, the satellite-based precision timing system based on Galileo system fusion is installed in the GNSS receiver.

[0104] The aforementioned satellite-based precise time synchronization method based on the fusion of the BeiDou / Galileo systems involves a receiver receiving observation data, broadcast ephemeris data, and corrections from both the BeiDou-3 and Galileo satellite systems. The two systems are then fused for time synchronization. The system clock biases between the two satellite systems are used as constants, white noise, and random walks, respectively, to construct estimation models. Simultaneously, a PPP fusion model for both satellite systems is constructed. Each estimation model is then incorporated into the fusion model for calculation. The estimation model with the best timing accuracy is selected as the optimal estimation model to correct the system clock bias and other satellite data, yielding the receiver clock bias parameters. These parameters are then used for clock discipline to achieve satellite-based precise time synchronization. This method enables high-precision time synchronization without a network, providing users in various environments with high-precision, stable, and reliable time information.

[0105] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0106] In one embodiment, such as Figure 5 As shown, a satellite-based precision timing device based on the fusion of the BeiDou / Galileo systems is provided, comprising: a satellite system data acquisition module 200, a system clock bias estimation model construction module 210, an optimal estimation model selection module 220, a receiver clock bias parameter acquisition module 230, and a satellite-based precision timing module 240, wherein:

[0107] The satellite system data acquisition module 200 is used to acquire satellite observation data, broadcast ephemeris data and service correction data sent by the BeiDou-3 satellite system and the Galileo satellite system, wherein the service correction data includes PPP-B2b correction data and HAS correction data sent by the two satellite systems respectively.

[0108] The system clock error estimation model construction module 210 is used to model the system clock error between two satellite systems as a constant, white noise and random walk respectively, and obtain the corresponding estimation model.

[0109] The optimal estimation model selection module 220 is used to construct a PPP fusion model for two satellite systems, and to input each of the estimation models into the PPP fusion model to calculate the result of the PPP fusion model, and to select the estimation model with the highest timing accuracy as the optimal estimation model.

[0110] The receiver clock bias parameter acquisition module 230 is used to correct the satellite observation data, broadcast ephemeris data and system clock bias transmitted by each satellite system to obtain the receiver clock bias parameters. The optimal estimation model is used when correcting the system clock bias.

[0111] The satellite-based precision timing module 240 is used to perform clock discipline using the receiver clock difference parameters in order to complete satellite-based precision timing.

[0112] Specific limitations regarding the satellite-based precision timing device based on the BeiDou / Galileo system fusion can be found in the limitations of the satellite-based precision timing method based on the BeiDou / Galileo system fusion described above, and will not be repeated here. Each module in the aforementioned satellite-based precision timing device based on the BeiDou / Galileo system fusion can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of the processor, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0113] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 6 As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a satellite-based precise timing method based on the fusion of the BeiDou / Galileo systems. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0114] Those skilled in the art will understand that Figure 6 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0115] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0116] Acquire satellite observation data, broadcast ephemeris data, and service corrections transmitted by the BeiDou-3 satellite system and the Galileo satellite system, wherein the service corrections include PPP-B2b corrections and HAS corrections transmitted by the two satellite systems respectively;

[0117] The system clock error between the two satellite systems is modeled as a constant, white noise, and random walk, respectively, to obtain the corresponding estimation model;

[0118] Construct a PPP fusion model for two satellite systems, and input each of the estimated models into the PPP fusion model to calculate the result of the PPP fusion model. The estimated model with the highest timing accuracy is taken as the optimal estimated model.

[0119] The satellite observation data, broadcast ephemeris data, and system clock bias transmitted by each satellite system are corrected to obtain the receiver clock bias parameters. The optimal estimation model is used when correcting the system clock bias.

[0120] Clock discipline is performed using the receiver clock bias parameters to achieve satellite-based precision time synchronization.

[0121] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0122] Acquire satellite observation data, broadcast ephemeris data, and service corrections transmitted by the BeiDou-3 satellite system and the Galileo satellite system, wherein the service corrections include PPP-B2b corrections and HAS corrections transmitted by the two satellite systems respectively;

[0123] The system clock error between the two satellite systems is modeled as a constant, white noise, and random walk, respectively, to obtain the corresponding estimation model;

[0124] Construct a PPP fusion model for two satellite systems, and input each of the estimated models into the PPP fusion model to calculate the result of the PPP fusion model. The estimated model with the highest timing accuracy is taken as the optimal estimated model.

[0125] The satellite observation data, broadcast ephemeris data, and system clock bias transmitted by each satellite system are corrected to obtain the receiver clock bias parameters. The optimal estimation model is used when correcting the system clock bias.

[0126] Clock discipline is performed using the receiver clock bias parameters to achieve satellite-based precision time synchronization.

[0127] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0128] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0129] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for precise satellite-based time service based on the integration of Beidou / Galileo systems, characterized in that, The method comprises: acquiring satellite observation data, broadcast ephemeris data and service corrections sent by the Beidou three-satellite system and the Galileo satellite system, wherein the service corrections comprise PPP-B2b corrections and HAS corrections sent by the two satellite systems respectively; modeling system clock differences between the two satellite systems as constants, white noise and random walks respectively to obtain corresponding estimation models; constructing a PPP fusion model of the two satellite systems and bringing each of the estimation models into the PPP fusion model to calculate a result of the PPP fusion model, and taking the estimation model corresponding to the highest time service accuracy as an optimal estimation model; respectively correcting satellite observation data, broadcast ephemeris data and system clock differences sent by each satellite system to obtain receiver clock difference parameters, wherein the optimal estimation model is used when the system clock differences are corrected; performing clock taming by using the receiver clock difference parameters to complete satellite-based precise time service.

2. The satellite-based precise timing method of claim 1, wherein, The PPP fusion model adopts: In the above equation, subscript IF indicates ionosphere-free combination observation value, subscript r indicates receiver, superscript C indicates Beidou three satellite system, superscript E indicates Galileo satellite system, P indicates pseudo-range observation value, ρ indicates satellite-ground distance, indicates receiver clock error in which pseudo-range hardware delay is absorbed in Beidou three system satellite observation equation, indicates satellite clock error, ISB indicates system bias in Galileo system satellite observation equation relative to Beidou three system satellite observation equation, λ IF indicates ionosphere-free combination hardware delay, T indicates troposphere delay, indicates float solution ambiguity parameter, and ε and ξ respectively indicate pseudo-range and carrier noise.

3. The satellite-based precise timing method of claim 2, wherein, In the combined observations, the Beidou three-satellite system adopts combined observations of B1I and B3I, and the Galileo satellite system adopts combined observations of E1 and E5a.

4. The satellite-based precise timing method of claim 2, wherein, The correction of the satellite observation data, the broadcast ephemeris data and the system clock differences sent by each satellite system to obtain the receiver clock difference parameters comprises: a plurality of error equations are constructed for errors of corresponding data by using model or parameter estimation; the receiver clock difference parameters are obtained by solving each of the error equations by using a Kalman filtering method.

5. The satellite-based precise timing method of claim 4, wherein, When the orbit errors and clock errors in the satellite observation data and the broadcast ephemeris data sent by each satellite system are corrected: the orbit data and the clock data of the two satellite systems are respectively obtained by analyzing data sent by the two satellite systems and calculating by using the analyzed broadcast ephemeris data; the real-time precise orbit and clock data of the corresponding satellite system are obtained by merging the PPP-B2b corrections and the HAS corrections with the orbit data and the clock data of the corresponding satellite system; the orbit errors and the clock errors in the corresponding satellite system are corrected by using the real-time precise orbit and clock data.

6. The satellite-based precise timing method of claim 5, wherein, The following formula is used when the real-time precise orbit data of the satellite system is calculated: In the above formula, X represents real-time precise orbit data, X brdc represents satellite coordinates calculated from broadcast ephemeris data, (e r , a , c ) represents a rotation matrix in three directions of longitude, latitude, and altitude, ΔO represents a PPP-B2b correction or a HAS correction, and r and respectively represent satellite velocity and position vectors.

7. The satellite-based precise timing method of claim 5, wherein, The following formula is used when the real-time precise clock data of the satellite system is calculated: In the above formula, T represents real-time precise clock error data, T brd represents satellite clock error data calculated according to broadcast ephemeris data, ΔT represents a PPP-B2b correction or a HAS correction, and c represents the speed of light.

8. The satellite-based precise timing method of claim 5, wherein, When the satellite observation data and the broadcast ephemeris data sent by each satellite system are corrected: modeling is used to correct satellite antenna phase center errors, relativistic effect errors, atmospheric errors, receiver antenna phase center errors and tidal errors; parameter estimation is used to correct tropospheric wet component errors, receiver clock difference errors, receiver coordinate errors, ambiguity errors and tropospheric wet component errors; wherein the receiver coordinate errors are estimated by using static, the receiver clock difference errors are estimated by using white noise, the ambiguity errors are estimated by using constants, and the tropospheric wet component errors are estimated by using random walks.

9. A satellite-based precise timing system based on Galileo system fusion, characterized in that, The satellite-based precise timing method according to any one of claims 1-8 is implemented in the satellite-based precise timing system, and the satellite-based precise timing system comprises a GNSS receiving unit, a solving unit, a taming unit and a crystal oscillator unit. The GNSS receiving unit is configured to acquire satellite observation data, broadcast ephemeris data and service corrections transmitted by the Beidou three-satellite system and the Galileo satellite system, wherein the service corrections comprise PPP-B2b corrections and HAS corrections transmitted by the two satellite systems respectively, and send the satellite observation data, the broadcast ephemeris data and the service corrections to the solving unit. The solving unit is configured to model system clock differences between the two satellite systems as constants, white noise and random walks respectively, obtain corresponding estimation models, construct a PPP fusion model of the two satellite systems, and calculate results of the PPP fusion model by respectively bringing each estimation model into the PPP fusion model, take an estimation model corresponding to the highest timing accuracy as an optimal estimation model, correct satellite observation data, broadcast ephemeris data and system clock differences transmitted by each satellite system respectively by using the optimal estimation model, and obtain receiver clock difference parameters, wherein the optimal estimation model is used to correct the system clock differences, and the receiver clock difference parameters are sent to the taming unit. The taming unit is configured to generate crystal oscillator taming information according to the receiver clock difference parameters, and send the crystal oscillator taming information to the crystal oscillator unit. The crystal oscillator unit is configured to tame according to the crystal oscillator taming information, and output a 10MHz signal to a GNSS receiver, so that the GNSS receiver outputs a 1PPS signal and UTC information according to an input signal of the 10MHz signal.

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