Time service providing method and apparatus

Abstract

The application discloses a time service providing method and device, in which real-time broadcast ionosphere models of various GNSS systems are fully utilized in user GNSS receiver position and time service calculation, real-time ionosphere error improvement is ensured to be optimal, higher precision, more continuity and more stability of GNSS positioning and time service are provided for users without increasing additional complex operation amount, and multi-system GNSS satellite positioning is supported. More preferably, when ionosphere parameter is switched, deviation caused by model error of two groups of parameters before and after the switching is calculated, position and clock difference jumps when ionosphere error correction is performed on different parameters and models are eliminated, and the precision and reliability of the position and the clock difference are effectively improved.

Description

Technical Field

[0001] This application relates to, but is not limited to, satellite navigation technology, and in particular to a method and apparatus for providing timing services. Background Technology

[0002] With the rapid development of modern science and technology, various industries such as communications, power, transportation, and national defense have increasingly higher requirements for the accuracy and reliability of time. High-precision time references have become a fundamental guarantee for fields such as communications, power, broadcasting, security monitoring, and industrial control. Global Navigation Satellite System (GNSS) satellites can provide global users with all-weather, high-precision positioning, navigation, and timing (PNT) services, and applications based on GNSS satellite timing are becoming increasingly widespread globally.

[0003] GNSS timing methods include the single-station method. The single-station method requires no synchronous observations, has no limit on the number of users, and is flexible and convenient to use. For single-station users, ionospheric delay error is one of the main error sources affecting satellite PNT services, and ionospheric error correction algorithms are a key factor affecting the accuracy of user positioning and timing. For single-station GNSS applications, ionospheric errors can be eliminated through a combination of observations from dual-frequency carriers or pseudoranges. However, due to the limitations of single-frequency GNSS receivers in signal processing and correction, they are more susceptible to ionospheric delay errors. Therefore, the single-station method is not suitable for single-frequency users.

[0004] Improving the position and timing service performance of GNSS receivers to provide users with more accurate and robust GNSS services is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This application provides a method and apparatus for providing timing services, which can improve the timing service performance of GNSS receivers, thereby providing users with higher precision and more robust GNSS services.

[0006] This application provides a method for providing a time synchronization service, including:

[0007] Determine the first ionospheric error model value of each satellite corresponding to the saved first ionospheric parameter information at the current time, and determine the second ionospheric error model value of each satellite corresponding to the second ionospheric parameter information parsed at the current time;

[0008] Time synchronization services are provided using the first ionospheric error model value and the second ionospheric error model value.

[0009] This application also provides a computer-readable storage medium storing computer-executable instructions for performing any of the time synchronization service provision methods described above.

[0010] This application embodiment further provides a timing service providing apparatus, including a memory and a processor, wherein the memory stores the following instructions executable by the processor: steps for performing the timing service providing method described in any of the above claims.

[0011] The timing service provision method and apparatus provided in this application fully utilize the real-time ionospheric models of each GNSS system in the timing calculation of the user's GNSS receiver, ensuring optimal improvement of real-time ionospheric error. Moreover, it provides users with higher precision, more continuous and more stable GNSS positioning and timing services without adding extra complex calculations, and supports multi-system GNSS satellite positioning.

[0012] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0013] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0014] Figure 1 This is a flowchart illustrating the method for providing time synchronization services in the embodiments of this application;

[0015] Figure 2 This is a flowchart illustrating the first embodiment of the time synchronization service provision method in this application.

[0016] Figure 3 This is a flowchart illustrating a second embodiment of the method for providing time synchronization services in this application.

[0017] Figure 4 This is a schematic diagram of the composition of the timing service providing device in the embodiments of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

[0019] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0021] It is understood that the terms "first" and "second" used in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0023] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0024] Ionospheric error is a general concept describing ionospheric error, while ionospheric correction models are specific mathematical models or algorithms used to correct ionospheric errors. An ionospheric correction model is a specific implementation of an ionospheric error model, and a broadcast ionospheric model is a specific type of ionospheric correction model.

[0025] The four major global satellite navigation and positioning systems employ different broadcast ionospheric models: the US Global Positioning System (GPS) uses the Klobuchar model, which calculates the ionospheric delay at the GPS L1 frequency based on geographic latitude and local time, and is currently the most widely used model; the European Union's Galileo system mainly uses the Ne-Quick model based on three-dimensional electron density, directly obtaining the ionospheric error by integrating the electron density; China's BeiDou system supports two different broadcast ionospheric correction models. BeiDou-2 uses the BeiDou Klobuchar model, whose basic algorithm is basically the same as the GPS Klobuchar model, but there are differences in the reference frame and details compared to the GPS model. The BeiDou-3 global service uses the BDGIM model.

[0026] The BeiDou Navigation Satellite System (BDS) satellites broadcast the 8 parameters of the BeiDou Klobuchar model at frequencies B1I and B3I, applicable only to China and surrounding areas. The Medium Earth Orbit (MEO) and Inclined Geosynchronous Orbit (IGSO) satellites in the BeiDou-3 constellation broadcast the 9 parameters of the BDGIM model at frequencies B1c, B2a, and B2b, applicable to global ionospheric delay correction. Russia's GLONASS Global Navigation Satellite System does not provide models or parameters for estimating ionospheric errors in its interface documents and navigation messages. Generally, models from other systems can be used to estimate ionospheric errors in GLONASS satellite observations. In the future, GLONASS code division multiple access (CDMA) navigation messages will broadcast three ionospheric parameters.

[0027] Because the total electron content of the ionosphere varies with altitude, time, season, intensity of solar activity, and the user's location, the broadcast ionospheric parameters of each system are updated in real time based on monitoring results to ensure the accuracy of ionospheric error model corrections. The BeiDou Klobuchar and BDGIM models update their parameters every two hours (2h), the Galileo Ne-Quick model every day, and the GPS Klobuchar model every 1 to 7 days. In practical engineering applications, single-station GNSS receivers typically analyze and save the latest ionospheric parameters in real time. The next time the GNSS receiver is powered on, it reads and uses the saved ionospheric parameters until new ionospheric parameters are analyzed and updated during operation.

[0028] Due to differences in system models and parameters, the ionospheric models and broadcast ionospheric parameters of different GNSS systems exhibit significant differences when calculating the ionospheric model error value (i.e., the difference or deviation between the ionospheric correction value estimated using the ionospheric model and the actual ionospheric delay) for the same satellite at the same time. Furthermore, consistency analysis of the ionospheric model parameters shows that the same ionospheric model can exhibit significant jumps in ionospheric model error values ​​when its adjacent ionospheric parameters are updated. The worse the consistency between two sets of adjacent ionospheric model parameters, the larger the jump in the calculated ionospheric model error value before and after the parameter update. For single-satellite time synchronization users, these jumps in ionospheric model error values ​​directly lead to discontinuous time synchronization services. For multi-satellite time synchronization users, positioning and timing accuracy depends on the combined impact of the ionospheric delay jumps of the satellite used at the current epoch. Ionospheric model value jumps may also occur at the boundary between local day and night. These jumps are not caused by parameter updates but by segmented modeling of the ionospheric model.

[0029] To address the issue of fluctuating positioning and timing results caused by ionospheric parameter updates during the operation of a single-site receiver after startup, a short-term solution can maintain the use of the first set of ionospheric parameters without updating, directly avoiding result fluctuations due to parameter updates and ensuring short-term stability. However, for receivers operating for extended periods, this approach leads to a decrease in the accuracy of the ionospheric error model after prolonged periods without ionospheric parameter updates, resulting in a significant decline in positioning and timing accuracy.

[0030] Analysis and research related to ionospheric models mainly focus on the analysis of ionospheric variation characteristics and related modeling methods or model improvement, the analysis of regional ionospheric model construction methods, and the evaluation and performance comparison of different ionospheric models using GNSS data within specific time periods and regions. However, related analyses and research on ionospheric models have not considered how to improve the problem of position and timing result jumps when using multiple existing broadcast ionospheric models and updating parameters, nor have they provided solutions for ensuring the position and timing stability of single-station, single-frequency GNSS users during model switching or parameter updates. Therefore, this application provides a timing service provision method, such as... Figure 1 As shown, it may include:

[0031] Step 100: Determine the first ionospheric error model value of each satellite corresponding to the saved first ionospheric parameter information at the current time, and determine the second ionospheric error model value of each satellite corresponding to the second ionospheric parameter information obtained at the current time.

[0032] In one exemplary instance, the second ionosphere parameter information differs from the first ionosphere parameter information.

[0033] In one exemplary instance, obtaining the first or second ionospheric error model value in step 100 may include:

[0034] Obtain the user observations from the GNSS receiver at the current time;

[0035] Based on the user observations obtained at the current moment, and the first or second ionospheric parameter information, calculate the first or second ionospheric error model value of each satellite at the current moment.

[0036] In one embodiment, the first or second ionospheric parameter information typically includes ionospheric model parameters. For example, the Klobuchar model may include parameters such as α and β.

[0037] Step 101: Provide timing services using the first ionospheric error model value and the second ionospheric error model value.

[0038] In one exemplary instance, step 101 may include:

[0039] The receiver clock error of each satellite at the current time is calculated based on user observations, the first ionospheric error model value, and the second ionospheric error model value.

[0040] The time synchronization service is provided using the calculated receiver clock difference.

[0041] In one exemplary instance, the time synchronization service provision method provided in this application embodiment further includes:

[0042] Calculate the deviation between the first ionospheric error model value and the second ionospheric error model value for each satellite;

[0043] The ionospheric error of each satellite is corrected by using the calculated second ionospheric error model value of each satellite, or by using the second ionospheric error model value and the deviation respectively, so as to obtain the PVT position solution at the current time.

[0044] In one exemplary instance, step 101 may include:

[0045] Calculate the receiver clock error of each satellite at the current time based on the PVT position solution, the first ionospheric error model value, and the second ionospheric error model value;

[0046] The time synchronization service is provided using the calculated receiver clock difference.

[0047] The timing service provision method and apparatus provided in this application fully utilize the real-time broadcast ionospheric model of each GNSS system in the timing calculation of the user's GNSS receiver, ensuring optimal improvement of real-time ionospheric error. Moreover, it provides users with higher precision, more continuous and more stable GNSS positioning and timing services without adding extra complex calculations, and supports multi-system GNSS satellite positioning.

[0048] Figure 2 This is a flowchart illustrating the first embodiment of the time synchronization service provision method in this application, as shown below. Figure 2 As shown, it may include:

[0049] Step 200: Obtain the user observations from the GNSS receiver at the current time, as well as the latest set of first ionospheric parameter information that has been saved.

[0050] In one exemplary instance, the current time T k User observations from a GNSS receiver can include information such as pseudorange, carrier phase, and Doppler shift of the received satellite signal. This information is used for positioning and navigation calculations. In one embodiment, GNSS data processing software or tools can be used to select a receiver observation file or data stream, ensuring that it is captured in real time. This allows the current time T to be extracted from the software interface or command line. k GNSS user observations. Specific implementations may vary depending on the software used and are not intended to limit the scope of protection of this application.

[0051] In one exemplary instance, ionospheric parameters are typically broadcast by GNSS satellites and are updated periodically. In one embodiment, ionospheric parameter information can be extracted and saved from the GNSS broadcast data stream using software or tools such as GNSS data processing software. The latest set of saved ionospheric parameter information (Ion) data (A) Typically includes ionospheric model parameters. For example, the Klobuchar model may include parameters such as α and β.

[0052] Step 201: Based on the user observations and first ionospheric parameter information obtained at the current moment, calculate the first ionospheric error model value of each satellite at the current moment.

[0053] In one exemplary instance, the first ionospheric error model value Ion A (T k The ionospheric model used is consistent with the latest set of first ionospheric parameter information. data (A) Matching, for example: the latest set of first ionospheric parameter information Ion data(A) consists of eight parameters resolved from the GPS system; therefore, the ionospheric model used is the GPS Klobuchar model. Another example: the latest set of first ionospheric parameter information (Ion...) data (A) If the eight parameters are parsed from the BDS system, then the ionospheric model used is the BeiDou Klobuchar model; another example: the latest set of first ionospheric parameter information Ion data (A) is the nine parameters resolved from the BDS system, therefore, the ionospheric model used is the BeiDou BDGIM model; another example: the latest set of first ionospheric parameter information Ion data (A) are the three parameters resolved from the Galileo system. Therefore, the ionospheric model used is the Ne-Quick model or other improved models.

[0054] In one exemplary instance, if multiple sets of ionospheric parameter values ​​that are valid for different systems exist simultaneously, the ionospheric model and parameters with the best accuracy in the user's area can be selected based on the user's location and experience to calculate the ionospheric error model values ​​of each satellite at the current moment.

[0055] It should be noted that the above-mentioned first ionospheric error model value Ion A (T k The ionospheric models and parameters used are merely illustrative and are not intended to limit the scope of protection of this application. That is to say, the ionospheric models used in step 301 are not limited to the ionospheric models provided in the interface files of each system. Other improved and applicable ionospheric models can be used for broadcast ionospheric parameters, such as the Klobuchar-like model of GPS, the Ne-QuickG or NTCM model of Galileo, or other more applicable models.

[0056] In one exemplary instance, if the GNSS receiver user can receive Satellite-Based Augmentation System (SBAS) signals, then the ionospheric error model value in step 201 can be calculated using the latest real-time grid ionospheric information and the grid ionospheric model. Furthermore, the broadcast ionospheric parameters can come from default values ​​stored in the GNSS receiver, ionospheric parameter values ​​stored in the storage medium, or available ionospheric parameter values ​​obtained through external configuration or external link transmission.

[0057] The calculation of the ionospheric error model value in step 201 is a common technique used by those skilled in the art. The specific implementation is not intended to limit the scope of protection of this application, and will not be elaborated here.

[0058] Step 203: Correct the ionospheric error of each satellite by using the calculated first ionospheric error model value of each satellite to obtain the PVT position solution at the current time.

[0059] In this step, the PVT position solution represents the estimated values ​​of position, velocity, and time.

[0060] In one exemplary instance, taking into full account satellite-related errors, signal propagation-related errors, and receiver-side errors, the practical form of the pseudorange primitive observation equation of the GNSS receiver can be expressed as shown in Equation (1):

[0061] P i =R i +Ion i (1)

[0062] In formula (1), P i Ion represents the pseudorange observation of the i-th satellite; i R represents the ionospheric error model value for the i-th satellite; i R represents the theoretical distance of the i-th satellite, including all errors except for the ionospheric error term. i This can be represented as shown in formula (2):

[0063]

[0064] In formula (2), r i Let represent the geometric distance between the position of the i-th satellite and the receiver; c represents the speed of light; This represents the receiver clock bias used for pseudorange calculation of the i-th satellite; Tgd represents the satellite-end clock bias of the i-th satellite. i Trop represents the group delay of the i-th satellite. i ε represents the tropospheric delay of the i-th satellite; i This represents the pseudorange observation noise of the i-th satellite. Wherein, the satellite position and satellite-end clock error of the i-th satellite are... Group delay Tgd i All can be calculated from broadcast ephemeris; the tropospheric delay Trop of the i-th satellite. i The pseudorange observation noise ε of the i-th satellite can be calculated using a model. i It can be weakened and then ignored by methods such as carrier phase smoothing.

[0065] In one embodiment, for a given set of first ionospheric error model values ​​Ion... A (T kIn the case of Ion in formula (1), i Let T be the current time. k The first ionospheric error model value Ion for the i-th satellite A (T k ) i Ion i =Ion A (T k ) i At this point, step 103 may include:

[0066] Using the current time T k The first ionospheric error model value Ion for the i-th satellite A (T k ) i Perform the current time T k The ionospheric error correction of the i-th satellite is calculated in real time using formulas (1) and (2). k PVT position solution X pvt (T k ).

[0067] In one exemplary instance, such as Figure 3 As shown, steps 2021 and 2022 may be included before step 203:

[0068] Step 2021: Detect the new set of second ionospheric parameter information at the current moment, and note that the second ionospheric parameter information is different from the first ionospheric parameter information. Calculate the second ionospheric error model value of each satellite at the current moment using the second ionospheric parameter information.

[0069] In one exemplary instance, the detection of a new set of second ionospheric parameter information (Ion) at the current moment is performed. data (B) The specific steps and operations may vary depending on the GNSS receiver model and GNSS data processing software. Typically, the GNSS receiver and data processing software will automatically resolve the ionospheric parameters. If a new set of second ionospheric parameter information (Ion) is detected at the current moment... data (B) Furthermore, the resolved second ionosphere parameter information Ion data (B) The calculated Ion value of the first ionospheric error model for each satellite at the current time. A (T k ) parameter (here referring to the Ion value used in calculating the error model of the first ionosphere) A (T k If the parameters used are different, then the second ionosphere parameter information (Ion) will be utilized. data(B) Calculate the second ionospheric error model value Ion for each satellite at the current time. B (T k ).

[0070] In one exemplary instance, the second ionosphere parameter information Ion is utilized. data (B) Calculate the second ionospheric error model value Ion for each satellite at the current time. B (T k This can include: based on the user observations obtained at the current time and the second ionospheric parameter information (Ion). data (B) Calculate the second ionospheric error model value Ion for each satellite at the current time. B (T k Specifically, the implementation is the same as the first ionospheric error model value Ion in step 201. A (T k The calculation is consistent with that of ), so it will not be repeated here.

[0071] It should be noted that the parsing of the new set of second ionospheric parameter information at the current time in step 2021 and the calculation of the first ionospheric error model value of each satellite at the current time in step 201 do not have a strict execution order, and are not used to limit the scope of protection of this application.

[0072] Step 2022: Calculate the deviation between the first ionospheric error model value and the second ionospheric error model value for each satellite.

[0073] In one exemplary instance, step 2022 calculates and saves the second ionospheric error model value Ion for each satellite. B (T k ) and the first ionospheric error model value Ion A (T k The difference between the two values ​​is used to obtain the first ionospheric error model value, Ion. A (T k ) and the second ionosphere error model value Ion B (T k The deviation ΔIon B-A (T k ).

[0074] In this embodiment of the application, the two sets of ionospheric parameters, namely the first ionospheric parameter information Ion data (A) Information on second ionosphere parameters (Ion) data(B) can be parameters of the same type from the same system, or parameters of different types from different systems. The statistical results of ionospheric parameters and model correction rates of each system are all above 50%. Generally speaking, except for the eight parameters of the BeiDou Klobuchar model which mainly provides ionospheric error correction for the Chinese region, the eight parameters of the GPS Klobuchar model, the three parameters of the Galileo Ne-Quick model, and the nine parameters of the BDGIM model all provide ionospheric error correction for the global scope. The statistical results of their model correction rates do not show significant differences. However, the latest ionospheric parameters are generally closer to the overall variation law of the actual ionosphere in time and space. Therefore, the ionospheric error model value correction accuracy calculated using the latest ionospheric parameters in the embodiments of this application will be higher.

[0075] In one embodiment, steps 2021 and 2022 are included, meaning that the first ionospheric error model value Ion is calculated simultaneously. A (T k ), second ionospheric error model value Ion B (T k ), and deviation ΔIon B-A In the case of the value, step 203 is as follows: Figure 3 As shown in 2031, this includes: using the calculated second ionospheric error model values ​​of each satellite, or the second ionospheric error model values ​​and deviations respectively, to correct the ionospheric error of each satellite, in order to obtain the PVT position solution at the current moment. The specific implementation can be divided into the following two processing methods:

[0076] The second ionospheric error model value Ion can be calculated directly using the latest detected ionospheric parameters. B (T k To complete the ionospheric error correction, i.e., Ion in formula (1) i Let T be the current time. k The second ionospheric error model value Ion for the i-th satellite B (T k ) i Ion i =Ion B (T k ) i This approach is suitable for scenarios where users are more concerned with the absolute accuracy of real-time location. In this case, step 203 in this embodiment is as follows: Figure 3 Step 2031 may include:

[0077] Using the second ionospheric error model value Ion of the i-th satellite at the current time. B (T k ) iPerform the current time T k The ionospheric error correction of the i-th satellite is calculated in real time using formulas (1) and (2). k PVT position solution X pvt (T k ).

[0078] The Ion value can be used based on the error model value of the first ionosphere. A (T k ) and the second ionosphere error model value Ion B (T k The deviation ΔIon B-A Compensation for second ionospheric error model value Ion B (T k The value after ) is used to complete the ionospheric error correction, that is, Ion in formula (1) i For deviation ΔIon B-A Compensation for second ionospheric error model value Ion B (T k ) i The value after that, i.e., Ion i =Ion B (T k ) i -ΔIon B-A This approach is suitable for scenarios where users are more concerned with the continuity of location over a short period of time. In this case, step 103 in this embodiment is as follows: Figure 2 Step 2031 may include:

[0079] Using the longitude deviation ΔIon of the i-th satellite at the current time B-A Compensation for second ionospheric error model value Ion B (T k ) i The value after is used at the current time T. k The ionospheric error correction of the i-th satellite is calculated in real time using formulas (1) and (2). k PVT position solution X pvt (T k ).

[0080] Step 204: Calculate the receiver clock error of each satellite at the current time based on the first ionospheric error model value.

[0081] In one exemplary instance, for a given set of first ionospheric error model values ​​Ion... A (T k In the case of ), step 204 may include:

[0082] Based on the user location in the PVT location solution and the first ionospheric error model value Ion of the i-th satellite... A (T k ) i The current time T is calculated using formulas (1) and (2) respectively. k First receiver clock bias for the i-th valid satellite

[0083] First receiver clock bias for each satellite The current time T is obtained after weighted averaging. k First receiver clock bias at each frequency point The first receiver clock error obtained after weighted averaging is used as the receiver clock error for each frequency point at the current time.

[0084] In one embodiment, the first receiver clock bias for each satellite can be calculated according to formula (3). The current time T is obtained after weighted averaging. k First receiver clock bias at each frequency point

[0085] In one embodiment, for the case where the receiver clock error of each satellite at the current time is calculated based on the first ionospheric error model value, the current time T k First receiver clock difference dt r Values The calculation is shown in formula (3):

[0086]

[0087] In one exemplary instance, for the currently calculated effective first ionospheric error model value Ion... A (T k ), second ionospheric error model value Ion B (T k In the case of ), step 204 is as follows Figure 3 Step 2041 in the figure includes: calculating the receiver clock error of each satellite at the current time based on the first ionospheric error model value and the second ionospheric error model value.

[0088] In one embodiment, Figure 3 Step 2041 may specifically include:

[0089] Based on the user location in the PVT location solution and the first ionospheric error model value Ion of the i-th satellite... A (T k ) i The second ionospheric error model value Ion of the i-th satellite B (Tk ) i The current time T is calculated using formulas (1) and (2) respectively. k First receiver clock bias at each frequency point and the second receiver clock bias

[0090] First receiver clock bias for each satellite Second receiver clock bias The current time T is obtained by performing weighted averages separately. k First receiver clock bias at each frequency point Second receiver clock difference

[0091] Calculate and save the first receiver clock difference at each frequency point at the current time. and the second receiver clock bias clock deviation value Δdt r(B-A) As shown in formula (4),

[0092]

[0093] Calculate the current time T k The second receiver clock bias obtained after weighted averaging Clock deviation value Δdt r(B-A) The difference is taken as the current time T. k The receiver clock difference at each frequency point at the current time. That is, the clock difference at the current time T. k The receiver clock bias value for each satellite is...

[0094] In one embodiment, for the case where the receiver clock error of each satellite at the current time is calculated based on the first ionospheric error model value and the second ionospheric error model value, the current time T k First receiver clock difference dt r Values The calculation is shown in formula (3); the current time T k Second receiver clock difference dt r Values The calculation is shown in formula (5):

[0095]

[0096] In formulas (3) and (5), w nA w nB Indicates the current time T kThe weights for the clock bias of the nth satellite are determined. The weights can be obtained using existing calculation methods. Generally, they can be determined based on the signal quality of each satellite, such as signal-to-noise ratio, elevation angle, continuous tracking time, pseudorange residuals, and ionospheric model errors. The specific implementation is not intended to limit the scope of protection of this application. Reasonable weight values ​​can effectively suppress clock bias glitches in single-satellite observations while obtaining better receiver clock bias values ​​and clock deviation values ​​at each frequency.

[0097] Step 205: Provide timing service using the calculated receiver clock difference value.

[0098] In one exemplary instance, it may also include: the GNSS receiver clock bias at each subsequent time point is based on the latest set of ionospheric Ion values. data (B) Parameters are used to correct ionospheric errors and compensate for Δdt. r(B-A) This continues until the next set of the latest set of ionospheric parameters (i.e., the resolved third set of ionospheric parameter information) is obtained. data (c) and compared with the second ionospheric error model value Ion B (T k After the parameters are different, return to step 104 and apply formulas (3), (4) and (5) to Δdt again. r(B-A) The value is updated and used.

[0099] In practical applications, the timing service provision method provided in this application, once the latest set of ionospheric parameters is parsed in real time, estimates of the clock bias values ​​of the two receiver clock biases are made using the two currently existing sets of ionospheric parameters and their corresponding models. Subsequently, when switching to the latest real-time ionospheric parameters, ionospheric error correction and clock bias offset compensation are performed. This eliminates the receiver clock bias jump problem caused by switching to the latest parameters, while fully utilizing the real-time broadcast ionospheric models of each GNSS system, ensuring optimal real-time ionospheric error improvement. Furthermore, it provides users with higher precision, continuous, and stable GNSS position and timing services without adding extra complex computational load.

[0100] It should be noted that the known user position in step 204 is not limited to the calculated real-time position; other effective positions with higher precision can also be used. The specific implementation is not intended to limit the scope of protection of this invention. For example, for static scenes, externally configured or input precise coordinates or receiver-optimized fixed coordinates can be used; for dynamic scenes, a higher precision calculated input position can be used, and a more accurate user position can ensure a more stable and accurate receiver clock error.

[0101] The timing service provision method provided in this application fully utilizes the real-time broadcast ionospheric models of various GNSS systems in the calculation of user GNSS receiver position and timing, ensuring optimal improvement of real-time ionospheric errors. Moreover, it provides users with higher accuracy, more continuous, and more stable GNSS positioning and timing services without adding extra complex calculations, and supports multi-system GNSS satellite positioning. More preferably, when switching ionospheric parameters, the deviation caused by model errors is calculated based on the two sets of parameters before and after the switch, eliminating position and clock error jumps when correcting ionospheric errors with different parameters and models, effectively improving the accuracy and reliability of position and clock errors.

[0102] This application also provides a computer-readable storage medium storing computer-executable instructions for performing the timing service provision method described in any of the preceding claims.

[0103] This application further provides a timing service providing apparatus, including a memory and a processor, wherein the memory stores the following instructions executable by the processor: steps for performing the timing service providing method described in any of the preceding claims.

[0104] Figure 3 This is a schematic diagram of the composition of the timing service providing device in the embodiments of this application, such as... Figure 3 As shown, it includes at least: an acquisition unit and a processing unit, wherein,

[0105] The acquisition unit is used to determine the first ionospheric error model value of each satellite corresponding to the latest set of first ionospheric parameter information saved at the current time, and to determine the second ionospheric error model value of each satellite corresponding to the second ionospheric parameter information parsed at the current time.

[0106] The processing unit is used to provide timing services using the first ionospheric error model value and the second ionospheric error model value.

[0107] In one exemplary instance, the second ionosphere parameter information differs from the first ionosphere parameter information.

[0108] In one exemplary instance, the acquisition unit is further configured to: acquire the user observation value of the GNSS receiver at the current time;

[0109] The device may further include: an ionospheric parameter acquisition unit and an ionospheric error acquisition unit; wherein...

[0110] The ionospheric parameter acquisition unit is used to parse the second ionospheric parameter information at the current moment;

[0111] The ionospheric error acquisition unit is used to calculate the first ionospheric error model value / second ionospheric error model value of each satellite at the current time based on the user observation value and the first ionospheric parameter information / second ionospheric parameter information obtained at the current time; and to calculate the deviation between the first ionospheric error model value and the second ionospheric error model value of each satellite.

[0112] In one exemplary instance, the timing service providing apparatus of this application may further include: a PVT position solution acquisition unit, configured to use the calculated second ionospheric error model value of each satellite, or the deviation between the second ionospheric error model value and the first ionospheric error model value and the second ionospheric error model value to correct the ionospheric error of each satellite respectively, so as to obtain the PVT position solution at the current time.

[0113] In one embodiment, the PVT location solution acquisition unit can be used to:

[0114] Using the current time T k The first ionospheric error model value Ion for the i-th satellite A (T k ) i Perform the current time T k The ionospheric error correction of the i-th satellite is calculated in real time using formulas (1) and (2). k PVT position solution X pvt (T k ).

[0115] In one embodiment, the clock difference acquisition unit can be used to:

[0116] Based on the user location in the PVT location solution and the first ionospheric error model value Ion of the i-th satellite... A (T k ) i The current time T is calculated using formulas (1) and (2) respectively. k First receiver clock bias of the i-th satellite

[0117] First receiver clock bias for each satellite The current time T is obtained after weighted averaging. k First receiver clock bias at each frequency point The first receiver clock error obtained after weighted averaging is used as the receiver clock error for each frequency point at the current time.

[0118] In one embodiment, the PVT location solution acquisition unit is specifically used for:

[0119] Using the second ionospheric error model value Ion of the i-th satellite at the current time. B(T k ) i Perform the current time T k The ionospheric error correction of the i-th satellite is calculated in real time using formulas (1) and (2). k PVT position solution X pvt (T k ).

[0120] In one embodiment, the PVT location solution acquisition unit is specifically used for:

[0121] Using the longitude deviation ΔIon of the i-th satellite at the current time B-A Compensation for second ionospheric error model value Ion B (T k ) i The value after is used at the current time T. k The ionospheric error correction of the i-th satellite is calculated in real time using formulas (1) and (2). k PVT position solution X pvt (T k ).

[0122] In one exemplary instance, the timing service providing apparatus of this application may further include: a clock difference acquisition unit, configured to calculate the receiver clock difference of each satellite at the current time based on the first ionospheric error model value.

[0123] The processing unit is used to provide timing services using the calculated receiver clock difference.

[0124] In one embodiment, the clock difference acquisition unit can be used to:

[0125] Based on the user location in the PVT location solution and the first ionospheric error model value Ion of the i-th satellite... A (T k ) i The second ionospheric error model value Ion of the i-th satellite B (T k ) i The current time T is calculated using formulas (1) and (2) respectively. k First receiver clock bias of the i-th satellite and the second receiver clock bias

[0126] First receiver clock bias for each satellite Second receiver clock bias The current time T is obtained by performing weighted averages separately. k First receiver clock bias at each frequency point Clock difference with the first receiver

[0127] Calculate and save the first receiver clock error after weighted averaging. and the second receiver clock bias clock deviation value Δdt r(B-A) ;

[0128] Calculate the current time T k The second receiver clock bias obtained after weighted averaging Clock deviation value Δdt r(B-A) The difference is taken as the current time T. k The receiver clock difference at each frequency point at the current time.

[0129] The timing service providing device provided in this application embodiment makes full use of the real-time broadcast ionospheric model of each GNSS system in the calculation of user GNSS receiver location and timing, ensuring optimal improvement of real-time ionospheric error. Moreover, it provides users with higher precision, more continuous and more stable GNSS positioning and timing services without adding extra complex calculations, and supports multi-system GNSS satellite positioning.

[0130] More preferably, when switching ionospheric parameters, the deviation caused by the model error is calculated based on the two sets of parameters before and after the switch, eliminating the position and clock error jumps when correcting ionospheric errors with different parameters and models, and effectively improving the accuracy and reliability of position and clock error.

[0131] Although the embodiments disclosed in this application are as described above, the content described is merely for the purpose of understanding this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A method for providing time synchronization services, characterized in that, include: Obtain the user observations from the GNSS receiver of the satellite navigation and positioning system at the current moment; The first ionospheric error model value of each satellite at the current moment is determined based on the user observation value obtained at the current moment and the saved first ionospheric parameter information. The second ionospheric error model value of each satellite at the current moment is determined based on the user observation value obtained at the current moment and the second ionospheric parameter information obtained at the current moment. Calculate the corresponding receiver clock bias and clock deviation values ​​based on user observations, the first ionospheric error model value, and the second ionospheric error model value, and determine the receiver clock bias at each frequency point at the current time based on the corresponding receiver clock bias and clock deviation values. Time synchronization services are provided using a defined receiver clock difference.

2. A method for providing time synchronization services, characterized in that, include: Obtain the user observations from the GNSS receiver of the satellite navigation and positioning system at the current moment; The first ionospheric error model value of each satellite at the current moment is determined based on the user observation value obtained at the current moment and the saved first ionospheric parameter information. The second ionospheric error model value of each satellite at the current moment is determined based on the user observation value obtained at the current moment and the second ionospheric parameter information obtained at the current moment. Calculate the receiver clock error and clock deviation values ​​based on the current PVT position solution, the first ionospheric error model value, and the second ionospheric error model value, and determine the receiver clock error at each frequency point at the current time based on the corresponding receiver clock error and clock deviation values. Time synchronization services are provided using a defined receiver clock difference.

3. The time synchronization service provision method according to claim 2, wherein, The PVT position solution at the current moment is obtained according to the following steps: The ionospheric error of each satellite is corrected using the second ionospheric error model value of each satellite in order to obtain the PVT position solution at the current time. or, Calculate the deviation between the first ionospheric error model value and the second ionospheric error model value for each satellite; use the second ionospheric error model value and the deviation to correct the ionospheric error of each satellite to obtain the PVT position solution at the current time.

4. The time synchronization service provision method according to claim 2, wherein, The step of calculating the receiver clock bias and clock deviation values ​​based on the current PVT position solution, the first ionospheric error model value, and the second ionospheric error model value, and determining the receiver clock bias at each frequency point at the current time based on the corresponding receiver clock bias and clock deviation values, includes: Based on the user's position in the PVT position solution, the first ionospheric error model value of the i-th satellite, and the second ionospheric error model value of the i-th satellite, the first receiver clock error and the second receiver clock error at each frequency point at the current time are calculated respectively. The first receiver clock error and the second receiver clock error of each satellite are weighted and averaged to obtain the first receiver clock error and the second receiver clock error at each frequency point at the current time. The clock deviation value of the first receiver clock error and the second receiver clock error at each frequency point at the current time is calculated. The difference between the second receiver clock error obtained by calculating the weighted average at the current time and the clock deviation value is taken as the receiver clock error at each frequency point at the current time.

5. The time synchronization service provision method according to claim 4, wherein, The current time is calculated using the following formula. The first receiver clock bias or the second receiver clock bias of the i-th satellite: ,in, Represents the pseudorange observations of the i-th satellite; This represents the first or second ionospheric error model value for the i-th satellite. This represents the theoretical distance value of the i-th satellite, which includes all errors except for the ionospheric error term. in, Represented as: , Let represent the geometric distance between the position of the i-th satellite and the receiver; c represents the speed of light; This represents the clock bias of the first receiver or the clock bias of the second receiver calculated using the pseudorange of the i-th satellite. This represents the satellite-end clock bias of the i-th satellite; This represents the group delay of the i-th satellite; This represents the tropospheric delay of the i-th satellite; This represents the pseudorange observation noise of the i-th satellite.

6. The method for providing time synchronization services according to claim 4, further comprising: The receiver clock bias at subsequent times is corrected for ionospheric error and compensated for the deviation based on the latest ionospheric parameters until the next set of the latest ionospheric parameters is resolved. Then, the step of calculating the receiver clock bias of each satellite at the current time based on the first ionospheric error model value and the second ionospheric error model value is returned, and the clock bias value is updated.

7. A computer-readable storage medium storing computer-executable instructions for performing the timing service provision method of claim 1 or any one of claims 2-6.

8. A timing service providing apparatus, comprising a memory and a processor, wherein, The memory stores the following instructions executable by a processor: steps for performing the timing service provision method as described in claim 1 or any one of claims 2-6.

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