Method and device for determining encoding precision and updating period of satellite clock and orbit correction product integrity information

Abstract

The application discloses a kind of satellite clock orbit correction product integrity information coding precision and update cycle determination method and device, belong to satellite navigation technical field.The method receives the real-time observation data of integrity monitoring station network and satellite clock orbit correction product integrity information by PPP-RTK cloud master station, constructs protection level prediction model based on the required navigation performance of user, and the sensitivity analysis is carried out to the protection level change caused by integrity information change, determines coding precision and average failure duration.Combining average failure duration constructs update cycle determination model, finally forms the coding and broadcast scheme of satellite clock orbit correction product integrity information.The application significantly improves the reliability of broadcast data and the integrity of PPP-RTK real-time positioning, and provides important support for intelligent, unmanned application of high-precision, high-integrity space-time information demand.

Description

Technical Field

[0001] This invention belongs to the field of satellite navigation technology, specifically relating to a method and apparatus for determining the encoding accuracy and update cycle of satellite clock-orbit correction product integrity information. Background Technology

[0002] With the completion of the global network of the BeiDou Navigation Satellite System (BDS), its applications in precise positioning, disaster monitoring, and intelligent transportation are becoming increasingly widespread. However, life safety-related fields such as autonomous driving and unmanned agriculture place higher demands on the accuracy and reliability of navigation services, and the existing integrity assurance mechanisms of satellite clock-orbit correction products are clearly insufficient.

[0003] Precise Point Positioning-Real-Time Dynamic Positioning (PPP-RTK) technology combines the wide-area coverage advantage of PPP with the fast convergence characteristics of RTK, providing users with centimeter-level high-precision positioning services. Users can quickly eliminate observation errors by receiving satellite clock-track correction products, but the integrity of these correction products directly affects the reliability of the terminal's positioning. Currently, the error statistical characteristics of satellite clock-track correction products (such as user ranging accuracy σ) are... URA and nominal deviation b nom The lack of effective encoding and broadcasting schemes prevents users from assessing the reliability of location results in real time, thus hindering the application of PPP-RTK technology in critical areas of life safety.

[0004] Therefore, there is an urgent need for a method that can dynamically determine the encoding accuracy and update cycle of satellite clock-orbit correction product integrity information to ensure the reliability of broadcast data and meet the needs of high-precision, high-integrity navigation services. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method and apparatus for determining the encoding accuracy and update cycle of satellite clock-track correction product integrity information. Based on integrity information generated by a PPP-RTK cloud-based master control station, a protection level prediction model is constructed according to the user's required navigation performance. The method then conducts amplitude and time sensitivity analysis of the predicted protection level changes exceeding limits due to changes in satellite clock-track correction product integrity information, thereby determining the encoding accuracy and update cycle of the satellite clock-track integrity information. Combining the encoding accuracy and update cycle, a satellite clock-track correction product encoding and broadcasting scheme is formed, ensuring the reliability of the broadcast data of the clock-track correction product integrity information. This is of great significance for expanding the application of PPP-RTK technology in life safety-related fields.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for determining the encoding accuracy and update cycle of integrity information for satellite clock track correction products, the method comprising:

[0008] Step 1: Receive real-time observation data from the integrity monitoring network and integrity information from satellite clock-orbit correction products through the PPP-RTK service platform;

[0009] Step 2: Based on the navigation performance required by users in the PPP-RTK application scenario, preprocess the real-time observation data and the integrity information of the satellite clock-orbit correction product to construct a protection level prediction model;

[0010] Step 3: Construct a protection level error prediction model based on the protection level prediction model, and determine the coding accuracy of the satellite clock track correction product integrity information through sensitivity analysis;

[0011] Step 4: Determine the average fault duration based on the determined encoding precision and the preprocessed integrity information;

[0012] Step 5: Construct an update cycle determination model based on the mean fault duration and determine the update cycle.

[0013] On the other hand, the present invention provides a device for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information, comprising:

[0014] The information acquisition module is used to receive real-time observation data from the integrity monitoring network and integrity information from satellite clock-orbit correction products through the PPP-RTK service platform;

[0015] The prediction model module is used to preprocess the real-time observation data and satellite clock-orbit correction product integrity information according to the navigation performance required by users in PPP-RTK application scenarios, and to construct a protection level prediction model.

[0016] The accuracy determination module is used to construct a protection level error prediction model based on the protection level prediction model, and determine the encoding accuracy of the integrity information of the satellite clock track correction product through sensitivity analysis.

[0017] The duration determination module is used to determine the average fault duration based on the determined encoding precision and the preprocessed integrity information;

[0018] The update cycle determination module is used to construct an update cycle determination model based on the mean fault duration and determine the update cycle.

[0019] Thirdly, the present invention provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned method for determining the encoding accuracy and update cycle of satellite clock-orbit correction product integrity information.

[0020] Fourthly, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enable the processor to implement the aforementioned method for determining the encoding accuracy and update cycle of satellite clock-orbit correction product integrity information.

[0021] The beneficial effects of this invention are as follows:

[0022] Improve positioning reliability: By dynamically determining the encoding accuracy and update cycle of satellite clock track correction product integrity information, the system ensures that the correction data received by users has high reliability, significantly improving the reliability and security of PPP-RTK positioning, and meeting the needs of critical life safety fields such as autonomous driving and unmanned agriculture.

[0023] Optimize data broadcasting efficiency: Based on sensitivity analysis and fault duration model, scientifically determine the update cycle of integrity information to avoid data redundancy or update lag, optimize communication bandwidth usage while ensuring performance, and improve broadcasting efficiency.

[0024] Support for high-precision application expansion: By accurately quantifying the impact of integrity information on the user's protection level, it provides real-time and reliable error statistical characteristics for high-precision navigation and positioning, promoting the widespread application of PPP-RTK technology in emerging fields such as intelligent transportation and precision agriculture.

[0025] Enhance system adaptability: Combine the navigation performance requirements of different application scenarios to dynamically adjust the coding accuracy and update cycle, ensuring that the system can flexibly cope with complex and ever-changing real-world environments and improve the robustness and adaptability of the overall service.

[0026] Filling a technological gap: It solves the problem of missing encoding and broadcasting schemes for the integrity information of satellite clock-orbit correction products in existing technologies, and provides key technical support for high integrity services of global satellite navigation systems (such as BDS, GPS, etc.). Attached Figure Description

[0027] Figure 1 This is a flowchart of a method for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information according to the present invention. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] This invention conducts sensitivity analysis on the amplitude and time of changes in user protection levels caused by changes in the integrity information of satellite clock-track correction products, determines the encoding accuracy and update cycle of the integrity information of satellite clock-track correction products, and comprehensively ensures the reliability of broadcast data and the integrity of PPP-RTK real-time positioning.

[0030] like Figure 1As shown, the present invention provides a method for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information, which specifically includes:

[0031] Step 1: Receive real-time observation data from the integrity monitoring network and integrity information from satellite clock-orbit correction products through the PPP-RTK service platform.

[0032] The system receives real-time data from the integrity monitoring station and integrity information from satellite clock-orbit correction products through the PPP-RTK service platform and accumulates this data for at least three months. The real-time observation data includes satellite ephemeris and observations, while the satellite clock-orbit correction product integrity information includes: σ URA and b nom , where σ URA For user ranging accuracy, b nom This is the nominal deviation.

[0033] Step 2: Based on the navigation performance required by the user in the PPP-RTK application scenario, preprocess the real-time observation data and the integrity information of the satellite clock-orbit correction product to construct a protection level prediction model.

[0034] First, determine the false negative rate P based on the navigation performance required by users in PPP-RTK application scenarios. md Therefore, the horizontal magnification factor K is determined. H and vertical magnification factor K v Then, the real-time observation data and satellite clock-orbit correction product integrity information accumulated over a long period in step 1 are preprocessed. The preprocessing includes:

[0035] (1) Calculate the satellite position and satellite elevation angle at different times based on the satellite ephemeris, exclude satellites with an elevation angle less than 5°, and obtain the effective satellite set;

[0036] (2) Calculate the observation matrix at different times based on the calculated satellite position and observations;

[0037] (3) Match the satellite clock track correction product integrity information accumulated in step 1 with the valid satellite set;

[0038] (4) Calculate the observation noise variance-covariance matrix based on the data matching results and the calculated satellite elevation angle. The observation noise variance-covariance matrix is ​​shown below, where m is the number of available satellites in the effective satellite set.

[0039] (1)

[0040] Where IF represents the non-ionosphere combination, σ Pi,IF (i=1,2,…,m) represents the standard deviation of noise in the ionospheric-free combined pseudorange observations of the i-th satellite. (i=1,2,…,m) represents the standard deviation of the noise of the ionospheric combined carrier phase observations for the i-th satellite.

[0041] After the calculation is completed, the horizontal magnification factor K is calculated. H Vertical magnification factor K v Constructing a protection level prediction model using the observation matrix and the observation noise variance-covariance matrix:

[0042] (2)

[0043] Wherein, HPL and VPL are the predicted protection levels in the horizontal and vertical directions, respectively. The current positioning error deviation value is given by the subscript k, which indicates the current epoch and will be omitted in the following description. and This represents the positioning error deviation values ​​in the horizontal and vertical directions at the current moment, where, and The subscript indicates the position of the element in the deviation vector. and These represent the standard deviations of positioning errors in the horizontal and vertical directions, respectively. , K H and K v These are the horizontal and vertical amplification factors determined based on the false negative rate, b. fm K represents the deviation caused by the fault. k and R k These are the Kalman gain matrix and the observation noise variance-covariance matrix, respectively. nom H is the nominal deviation value. k For the observation matrix, Let be the state transition matrix.

[0044] Step 3: Construct a protection level error prediction model based on the protection level prediction model, and determine the encoding accuracy of the satellite clock track correction product integrity information through sensitivity analysis.

[0045] First, a protection level error prediction model is constructed. The specific form of the protection level error prediction model is shown below:

[0046] (3)

[0047] Where dHPL and dVPL are the predicted protection level changes in the horizontal and vertical directions, respectively, and dσ is the predicted protection level change in the horizontal and vertical directions, respectively. URA and db nom To correct for changes in the integrity of satellite clock track products, including user ranging accuracy and nominal deviation, and These are the standard deviation coefficient and the deviation coefficient of the horizontal sensitivity, respectively. and These are the vertical sensitivity standard deviation coefficient and the deviation coefficient, respectively, obtained by differentiating the horizontal protection level prediction model expression and the vertical protection level prediction model expression with respect to the integrity information of the satellite clock track correction product.

[0048] Secondly, based on the navigation performance requirements of users in PPP-RTK application scenarios, the protection level change threshold, the different groups of change amplitudes of satellite clock-orbit correction product integrity information, and the user's required availability limits are determined. Taking the vertical direction as an example, according to equation (3), dσ in the vertical direction is calculated. URA and db nom Different amplitude changes lead to changes in the vertical prediction protection level. Availability is then calculated based on the ratio of the number of sites below the protection level change threshold to the total number of sites for that set of amplitude changes. The availability under this set of amplitude changes is compared to the user's required availability limit. If the availability under a certain set of integrity information change amplitudes is greater than the availability limit, then the change amplitude dσ of that set of integrity information is set. URA and db nom The encoding precision for integrity information is determined.

[0049] Step 4: Determine the average fault duration based on the determined encoding precision and the preprocessed integrity information.

[0050] In determining the integrity information of the satellite clock track correction product σ URA and b nom After determining the encoding precision, the encoding precision is used as the threshold for changes in integrity information. The σ values ​​of different satellites after step 2 are then statistically analyzed. URA and b nom The shortest time for changes to exceed the integrity information change threshold, combined with the shortest times from all satellites, is used to calculate the Mean Time Between Failures (MTBE) as follows:

[0051] (4)

[0052] Where, N sat The effective number of satellites is represented by TTE, which is the time during which the integrity information changes beyond the change threshold. The subscript i is the satellite index, and j is the index of the shortest time during which the integrity information changes beyond the change threshold.

[0053] Step 5: Construct an update cycle determination model based on the mean fault duration and determine the update cycle. Based on the coding accuracy determined in Step 4 and the update cycle, encode and broadcast the integrity information of the clock-orbit correction products of the effective satellites after preprocessing in Step 2.

[0054] After determining the Mean Time Between Failures (MTBE), an update cycle determination model is constructed based on the MTBE. The specific form is shown below:

[0055] (5)

[0056] Where TTU is the update cycle, x is the number of times the integrity information of the satellite clock-orbit correction product exceeds the change threshold, MTBE is the mean fault duration, and P(x) is the probability that the integrity information of the satellite clock-orbit correction product exceeds the change threshold x times within one update cycle. The update cycle can be calculated accordingly. Combining the determined coding precision and the determined update cycle, the integrity information σ of the satellite clock-orbit correction product is... URA and b nom Encode and broadcast.

[0057] On the other hand, the present invention provides a device for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information, which includes various modules capable of implementing the various steps of the aforementioned method, specifically including:

[0058] The information acquisition module is used to receive real-time observation data from the integrity monitoring network and integrity information from satellite clock-orbit correction products through the PPP-RTK service platform;

[0059] The prediction model module is used to preprocess the real-time observation data and satellite clock-orbit correction product integrity information according to the navigation performance required by users in PPP-RTK application scenarios, and to construct a protection level prediction model.

[0060] The accuracy determination module is used to construct a protection level error prediction model based on the protection level prediction model, and determine the encoding accuracy of the integrity information of the satellite clock track correction product through sensitivity analysis.

[0061] The duration determination module is used to determine the average fault duration based on the determined encoding precision and the preprocessed integrity information;

[0062] The update cycle determination module is used to construct an update cycle determination model based on the mean fault duration and determine the update cycle.

[0063] Thirdly, the present invention provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned method for determining the encoding accuracy and update cycle of satellite clock-orbit correction product integrity information.

[0064] Fourthly, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enable the processor to implement the aforementioned method for determining the encoding accuracy and update cycle of satellite clock-orbit correction product integrity information.

[0065] In summary, this invention proposes a method, apparatus, computer, and storage medium for determining the encoding accuracy and update cycle of real-time satellite clock-track correction product integrity information. By analyzing the sensitivity of the amplitude and time of changes in user protection levels caused by changes in the integrity information of satellite clock-track correction products, the encoding accuracy and update cycle of satellite clock-track correction product integrity information are determined, ensuring the reliability of broadcast data and the integrity of PPP-RTK real-time positioning. This is of great significance for supporting the expansion of satellite navigation applications towards intelligent and unmanned industries that require high-precision and high-integrity spatiotemporal information.

[0066] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for determining the encoding accuracy and update cycle of integrity information for satellite clock track correction products, characterized in that, The method includes: Step 1: Receive real-time observation data from the integrity monitoring network and integrity information from satellite clock-orbit correction products through the PPP-RTK service platform; Step 2: Based on the navigation performance required by users in the PPP-RTK application scenario, preprocess the real-time observation data and the integrity information of the satellite clock-orbit correction product to construct a protection level prediction model; Step 3: Construct a protection level error prediction model based on the protection level prediction model, and determine the coding accuracy of the satellite clock track correction product integrity information through sensitivity analysis; Step 4: Determine the average fault duration based on the determined encoding precision and the preprocessed integrity information; Step 5: Construct an update cycle determination model based on the Mean Time Between Failures (MTBE) and determine the update cycle. The update cycle determination model based on the MTBE is as follows: （5） Where TTU is the update cycle, x is the number of times the integrity information of the satellite clock-orbit correction product exceeds the change threshold, MTBE is the mean fault duration, and P(x) is the probability that the integrity information of the satellite clock-orbit correction product exceeds the change threshold x times within one update cycle; based on a determined coding precision and a determined update cycle, the preprocessed integrity information σ of the satellite clock-orbit correction product is... URA and b nom Encoding and broadcasting are performed, where σ URA For user ranging accuracy, b nom This is the nominal deviation.

2. The method for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information according to claim 1, characterized in that, In step 1, the real-time observation data includes satellite ephemeris and observation data. The integrity information of the satellite clock-orbit correction product includes user ranging accuracy and nominal deviation.

3. The method for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information according to claim 1, characterized in that, Step 2 includes: Based on the navigation performance required by users in PPP-RTK application scenarios, determine the horizontal and vertical magnification factors; Calculate the satellite position and satellite elevation angle at different times based on the satellite ephemeris, exclude satellites with an elevation angle of less than 5°, and obtain the effective set of satellites; Calculate the observation matrix at different times based on the calculated satellite positions and observations; The integrity information of the satellite clock track correction product is matched with the valid satellite set; Calculate the observation noise variance-covariance matrix based on the data matching results and the calculated satellite elevation angle: A protection level prediction model is constructed based on the horizontal amplification factor, the vertical amplification factor, the observation matrix, and the observation noise variance-covariance matrix.

4. The method for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information according to claim 3, characterized in that, The protection level prediction model is as follows: （2） Wherein, HPL and VPL are the predicted protection levels in the horizontal and vertical directions, respectively, and K... H K v These are the horizontal magnification factor and the vertical magnification factor, respectively. and These represent the standard deviations of positioning errors in the horizontal and vertical directions, respectively. and This indicates the positioning error deviation values ​​in the horizontal and vertical directions at the current moment.

5. The method for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information according to claim 1, characterized in that, Step 3 includes, Construct a protection level error prediction model: （3） Where dHPL and dVPL are the predicted protection level changes in the horizontal and vertical directions, respectively, and dσ is the predicted protection level change in the horizontal and vertical directions, respectively. URA and db nom To correct for changes in the integrity of satellite clock track products, including user ranging accuracy and nominal deviation, and These are the standard deviation coefficient and the deviation coefficient of the horizontal sensitivity, respectively. and These are the standard deviation coefficient and the deviation coefficient of the vertical sensitivity, respectively; Based on the navigation performance requirements of users in PPP-RTK application scenarios, the protection level change threshold, different sets of change amplitudes of satellite clock-orbit correction product integrity information, and the user's required availability limit are determined. If the availability under a certain set of integrity information change amplitudes is greater than the availability limit, then the change amplitude dσ of that set of integrity information is... URA and db nom The encoding precision for integrity information is determined.

6. The method for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information according to claim 1, characterized in that, Step 4 includes using the encoding precision as a threshold for changes in integrity information, and statistically analyzing the σ values ​​of different satellites after processing in step 2. URA and b nom The shortest time for changes to exceed the integrity information change threshold, combined with the shortest times from all satellites, is used to calculate the Mean Time Between Failures (MTBE) as follows: （4） Where, N sat The effective number of satellites is represented by TTE, which is the time during which the integrity information changes beyond the change threshold. The subscript i is the satellite index, and j is the index of the shortest time during which the integrity information changes beyond the change threshold.

7. A device for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information, used to execute the method according to any one of claims 1-6, characterized in that, include: The information acquisition module is used to receive real-time observation data from the integrity monitoring network and integrity information from satellite clock-orbit correction products through the PPP-RTK service platform; The prediction model module is used to preprocess the real-time observation data and satellite clock-orbit correction product integrity information according to the navigation performance required by users in PPP-RTK application scenarios, and to construct a protection level prediction model. The accuracy determination module is used to construct a protection level error prediction model based on the protection level prediction model, and determine the encoding accuracy of the integrity information of the satellite clock track correction product through sensitivity analysis. The duration determination module is used to determine the average fault duration based on the determined encoding precision and the preprocessed integrity information; The update cycle determination module is used to construct an update cycle determination model based on the mean fault duration and determine the update cycle.

8. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs; When one or more programs are executed by the one or more processors, the one or more processors implement the method for determining the encoding accuracy and update cycle of satellite clock-orbit correction product integrity information as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, It stores executable instructions, which, when executed by a processor, enable the processor to implement the method for determining the encoding accuracy and update cycle of satellite clock track correction product integrity information as described in any one of claims 1-6.

Images