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

Abstract

The invention discloses a satellite clock orbit correction product integrity information coding precision and updating period determination method and device, and belongs to the technical field of satellite navigation. According to the method, real-time observation data of an integrity monitoring station network and satellite clock orbit correction product integrity information are received through a PPP-RTK cloud master control station, a protection level prediction model is constructed based on navigation performance required by a user, and sensitivity analysis is performed on protection level changes caused by integrity information changes. And determining the coding precision and the average fault duration. And combining the average fault duration to construct an update period determination model, and finally forming a coding and broadcasting scheme of the integrity information of the satellite clock orbit correction product. According to the method, the reliability of broadcast data and the integrity of PPP-RTK real-time positioning are remarkably improved, and important support is provided for intelligent and unmanned application of high-precision and high-integrity space-time information requirements.

Description

Technical Field

[0001] The present invention belongs to the field of satellite navigation technology, and in particular relates to a method and device for determining the coding accuracy and update period of satellite clock and orbit correction products. Background Art

[0002] With the completion of the global network of the Beidou Navigation Satellite System (BDS), its applications in precision positioning, disaster monitoring, intelligent transportation, and other fields 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 integrity assurance mechanisms for existing satellite clock and orbit correction products are clearly insufficient.

[0003] Precision Point Positioning - Real-Time Kinematic (PPP-RTK) technology combines the wide-area coverage advantages 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 and orbit correction products, but the integrity of the correction products directly affects the reliability of terminal positioning. Currently, the error statistical characteristics of satellite clock and orbit correction products (such as user ranging accuracy σ URA and nominal deviation b nom ) The lack of effective coding and broadcasting solutions makes it impossible for users to evaluate the reliability of positioning results in real time, restricting 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 the integrity information of satellite clock and orbit correction products to ensure the reliability of the broadcast data and meet the needs of high-precision and high-integrity navigation services. Summary of the Invention

[0005] To address the above technical issues, the present invention provides a method and device for determining the encoding accuracy and update period of satellite clock and orbit correction product integrity information. Relying on the integrity information generated by the PPP-RTK cloud-based master station, a protection level prediction model is constructed based on the user's desired navigation performance requirements. This model conducts an amplitude and time sensitivity analysis of the predicted protection level exceeding the limit caused by changes in the integrity information of the satellite clock and orbit correction product, and determines the encoding accuracy and update period of the satellite clock and orbit integrity information. Combining the encoding accuracy and update period to form a satellite clock and orbit correction product encoding and broadcasting scheme ensures the reliability of the integrity information broadcast data of the clock and orbit correction product, which is of great significance for expanding the application of PPP-RTK technology in life safety-related fields.

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

[0007] A method for determining the coding accuracy and update period of satellite clock and orbit correction product integrity information, the method comprising:

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

[0009] Step 2: Preprocess the real-time observation data and satellite clock and orbit correction product integrity information according to the navigation performance required by users in the PPP-RTK application scenario, and build 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 encoding accuracy of the satellite clock and orbit correction product integrity information through sensitivity analysis;

[0011] Step 4: determining an average fault duration based on the determined encoding accuracy and the pre-processed integrity information;

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

[0013] In another aspect, the present invention provides a device for determining the encoding accuracy and update period of satellite clock and orbit correction product integrity information, comprising:

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

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

[0016] an accuracy determination module, configured 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 and orbit correction product through sensitivity analysis;

[0017] a duration determination module, configured to determine an average fault duration based on the determined encoding accuracy and the pre-processed integrity information;

[0018] The update cycle determination module is used to build an update cycle determination model according to the mean failure duration and determine the update cycle.

[0019] In a third aspect, the present invention provides an electronic device comprising: one or more processors; 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 period of the integrity information of the satellite clock and orbit correction product.

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

[0021] The beneficial effects of the present invention are:

[0022] Improve positioning reliability: By dynamically determining the coding accuracy and update cycle of the integrity information of satellite clock and orbit correction products, the correction data received by users is ensured to be highly reliable, significantly improving the reliability and safety of PPP-RTK positioning, meeting the needs of critical life safety areas such as autonomous driving and unmanned agriculture.

[0023] Optimize data broadcast efficiency: Based on sensitivity analysis and fault duration models, scientifically determine the update cycle of integrity information to avoid data redundancy or update lags. While ensuring performance, it optimizes communication bandwidth usage and improves broadcast efficiency.

[0024] Supporting the expansion of high-precision applications: By accurately quantifying the impact of integrity information on user protection levels, it provides real-time and reliable error statistics 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: Dynamically adjust encoding accuracy and update cycles based on the navigation performance requirements of different application scenarios to ensure the system can flexibly respond to complex and changing actual environments, thereby improving the robustness and adaptability of the overall service.

[0026] Filling the technological gap: It solves the problem of the lack of integrity information coding and broadcasting scheme for satellite clock and orbit correction products in the existing technology, and provides key technical support for the high integrity services of global satellite navigation systems (such as BDS, GPS, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a flow chart of a method for determining the coding accuracy and update period of satellite clock and orbit correction product integrity information of the present invention. DETAILED DESCRIPTION

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

[0029] The present invention conducts sensitivity analysis on the amplitude and time of excessive changes in user protection levels caused by changes in the integrity information of satellite clock and orbit correction products, determines the coding accuracy and update cycle of the integrity information of satellite clock and orbit correction products, and comprehensively guarantees 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 coding accuracy and update period of satellite clock and orbit correction product integrity information, specifically comprising:

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

[0032] Receive real-time data from integrity monitoring stations and satellite clock and orbit correction product integrity information through the PPP-RTK service platform and accumulate them for at least three months. The real-time observation data includes satellite ephemeris and observation quantities, and the integrity information of satellite clock and orbit correction products includes: URA and b nom , where σ URA is the user ranging accuracy, b nom is the nominal deviation.

[0033] Step 2: Preprocess the real-time observation data and satellite clock and orbit correction product integrity information according to the navigation performance required by users in the PPP-RTK application scenario, and build a protection level prediction model.

[0034] First, determine the missed detection rate P according to the navigation performance required by the user in the PPP-RTK application scenario. md , and then determine the horizontal magnification coefficient K H and the vertical magnification factor K v Then, the real-time observation data and satellite clock and orbit correction product integrity information accumulated over a long period of time in step 1 are preprocessed. The preprocessing includes:

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

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

[0037] (3) Match the integrity information of the satellite clock and orbit correction products accumulated over a long period of time in step 1 with the data of the valid satellite set;

[0038] (4) The observation noise variance-covariance matrix is ​​calculated 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 valid satellite set.

[0039] (1)

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

[0041] After the calculation is completed, according to the calculated horizontal magnification coefficient K H , vertical magnification factor K v , observation matrix and observation noise variance-covariance matrix to construct the protection level prediction model:

[0042] (2)

[0043] Among them, HPL and VPL are the predicted protection levels in the horizontal and vertical directions respectively. is the current positioning error deviation value, the subscript k represents the current epoch, which is omitted in the subsequent expression and is only expressed by and Indicates the current horizontal and vertical positioning error deviation values, where: and , the subscript indicates the position of the element in the deviation vector, and Represent the standard deviation of positioning error in the horizontal and vertical directions, , , K H and K v are the horizontal and vertical magnification coefficients determined according to the missed detection rate, b fm is the deviation caused by the fault, K k and R k are the Kalman gain matrix and the observation noise variance-covariance matrix, b nom is the nominal deviation value, H k is the observation matrix, is the state transition matrix.

[0044] 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 and orbit 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 as follows:

[0046] (3)

[0047] Where dHPL and dVPL are the predicted protection level changes in the horizontal and vertical directions respectively, dσ URA and db nom Correction of satellite clock and orbit product integrity information, user ranging accuracy, nominal deviation changes, and are the horizontal sensitivity standard deviation coefficient and the deviation coefficient, and are the standard deviation coefficient and bias coefficient of the vertical sensitivity, respectively, which are obtained by deriving 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 and orbit correction product.

[0048] Secondly, the protection level change threshold, the amplitude of the change of different groups of satellite clock and orbit correction product integrity information and the user's required availability limit are determined based on the required navigation performance of the user in the PPP-RTK application scenario. Taking the vertical direction as an example, according to formula (3), dσ in the vertical direction is calculated. URA and db nom Different amplitude changes lead to changes in the vertical predicted protection level. Then, the availability of the group under the change amplitude is calculated based on the ratio of the number of sites below the protection level change threshold to the total number of sites. Compare the availability under the group change amplitude with the user's required availability limit. If the availability under a certain group of integrity information change amplitude is greater than the availability limit, then the group of integrity information change amplitude dσ is increased. URA and db nom Determine the encoding accuracy of the integrity information.

[0049] Step 4: Determine an average fault duration based on the determined encoding accuracy and the pre-processed integrity information.

[0050] In determining the integrity information of satellite clock and orbit correction products σ URA and b nom After the coding accuracy is obtained, the coding accuracy is used as the integrity information change threshold, and the different satellite σ processed in step 2 are counted respectively. URA and b nom The shortest time that the change exceeds the integrity information change threshold, combined with the shortest time of all satellites, is used to calculate the mean duration of failure (MTBE) as follows:

[0051] (4)

[0052] Among them, N sat is the number of valid satellites, TTE is the time when the integrity information change exceeds the change threshold, subscript i is the satellite index, and j is the shortest time index when the integrity information change exceeds the change threshold.

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

[0054] After determining the mean failure duration MTBE, an update cycle determination model is constructed based on the mean failure duration MTBE. The specific form is as follows:

[0055] (5)

[0056] Where TTU is the update period, x is the number of times the integrity information of the satellite clock and orbit correction product exceeds the change threshold, MTBE is the mean duration of failure, and P(x) is the probability that the integrity information of the satellite clock and orbit correction product exceeds the change threshold x times within one update period. The update period can be calculated based on this. Combining the coding accuracy determined in the above with the determined update period, the integrity information of the satellite clock and orbit correction product σ is calculated. URA and b nom Encoding and broadcasting.

[0057] On the other hand, the present invention provides a device for determining the encoding accuracy and update period of satellite clock and orbit 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 station network and the integrity information of satellite clock and orbit correction products through the PPP-RTK service platform;

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

[0060] an accuracy determination module, configured 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 and orbit correction product through sensitivity analysis;

[0061] a duration determination module, configured to determine an average fault duration based on the determined encoding accuracy and the pre-processed integrity information;

[0062] The update cycle determination module is used to build an update cycle determination model according to the mean failure duration and determine the update cycle.

[0063] In a third aspect, the present invention provides an electronic device comprising: one or more processors; 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 period of the integrity information of the satellite clock and orbit correction product.

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

[0065] In summary, the present invention proposes a method, device, computer and storage medium for determining the coding accuracy and update period of the integrity information of real-time satellite clock and orbit correction products. By analyzing the sensitivity of the amplitude and time of the excessive changes in the user protection level caused by the changes in the integrity information of the satellite clock and orbit correction products, the coding accuracy and update period of the integrity information of the satellite clock and orbit correction products are determined, thereby ensuring the reliability of the broadcast data and the integrity of the PPP-RTK real-time positioning, and supporting the expansion of satellite navigation applications to intelligent and unmanned industries with high-precision and high-integrity spatiotemporal information requirements, which is of great significance.

[0066] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only 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 in the scope of protection of the present invention.

Claims

1. A method for determining the encoding accuracy and update period of satellite clock and orbit correction product integrity information, characterized in that: The method comprises: Step 1: Receive real-time observation data from the integrity monitoring station network and satellite clock and orbit correction product integrity information through the PPP-RTK service platform; Step 2: Preprocess the real-time observation data and satellite clock and orbit correction product integrity information according to the navigation performance required by users in the PPP-RTK application scenario, and build a protection level prediction model; 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 and orbit correction product integrity information through sensitivity analysis; Step 4: determining an average fault duration based on the determined encoding accuracy and the pre-processed integrity information; Step 5: Build an update cycle determination model based on the mean failure duration and determine the update cycle.

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

3. The method for determining the encoding accuracy and update period of satellite clock and orbit correction product integrity information according to claim 1, characterized in that: The step 2 includes: Determine the horizontal and vertical magnification factors based on the navigation performance required by users in PPP-RTK application scenarios; Calculate satellite positions and satellite elevation angles at different times based on satellite ephemeris, exclude satellites with elevation angles less than 5°, and obtain a valid satellite set; Calculate the observation matrix at different times based on the calculated satellite positions and observation quantities; Match the integrity information of satellite clock and orbit correction products 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, vertical amplification factor, observation matrix and observation noise variance-covariance matrix.

4. The method for determining the coding accuracy and update period of satellite clock and orbit correction product integrity information according to claim 3, characterized in that: The protection level prediction model is: （2） Among them, HPL and VPL are the predicted protection levels in the horizontal and vertical directions respectively, and K H , K v are the horizontal magnification factor and the vertical magnification factor respectively. and Represent the standard deviation of positioning error in the horizontal and vertical directions, and Indicates the horizontal and vertical positioning error deviation values ​​at the current moment.

5. The method for determining the coding accuracy and update period of satellite clock and orbit correction product integrity information according to claim 1, characterized in that: Said step 3 comprises, 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, dσ URA and db nom Correction of satellite clock and orbit product integrity information, user ranging accuracy, nominal deviation changes, and are the horizontal sensitivity standard deviation coefficient and the deviation coefficient, and are the standard deviation coefficient and deviation coefficient of sensitivity in the vertical direction respectively; According to the required navigation performance of users in PPP-RTK application scenarios, the protection level change threshold, the change amplitude of different groups of satellite clock and orbit correction product integrity information and the user's required availability limit are determined. If the availability under the change amplitude of a certain group of integrity information is greater than the availability limit, the change amplitude dσ of the integrity information of this group is changed. URA and db nom Determine the encoding accuracy of the integrity information.

6. The method for determining the coding accuracy and update period of satellite clock and orbit correction product integrity information according to claim 1, characterized in that: The step 4 includes taking the coding accuracy as the integrity information change threshold, and respectively counting the different satellites σ after the processing in step 2. URA and b nom The shortest time that the change exceeds the integrity information change threshold, combined with the shortest time of all satellites, is used to calculate the mean duration of failure (MTBE) as follows: （4） Among them, N sat is the number of valid satellites, TTE is the time when the integrity information change exceeds the change threshold, subscript i is the satellite index, and j is the shortest time index when the integrity information change exceeds the change threshold.

7. The method for determining the coding accuracy and update period of satellite clock and orbit correction product integrity information according to claim 1, characterized in that: The step 5 includes constructing an update cycle determination model according to the mean time between failures MTBE: （5） Where TTU is the update period, x is the number of times the integrity information of the satellite clock and orbit correction product exceeds the change threshold, MTBE is the mean duration of failure, and P(x) is the probability that the integrity information of the satellite clock and orbit correction product exceeds the change threshold x times within one update period. Based on the determined coding accuracy and the determined update period, the integrity information σ of the preprocessed satellite clock and orbit correction product is URA and b nom Encoding and broadcasting.

8. A device for determining the coding accuracy and update period of satellite clock and orbit correction product integrity information, characterized in that: include: The information acquisition module is used to receive real-time observation data from the integrity monitoring station network and the integrity information of satellite clock and orbit correction products through the PPP-RTK service platform; A prediction model module is used to pre-process the real-time observation data and satellite clock and orbit correction product integrity information according to the navigation performance required by users in PPP-RTK application scenarios, and build a protection level prediction model; an accuracy determination module, configured 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 and orbit correction product through sensitivity analysis; a duration determination module, configured to determine an average fault duration based on the determined encoding accuracy and the pre-processed integrity information; The update cycle determination module is used to build an update cycle determination model according to the mean failure duration and determine the update cycle.

9. An electronic device, characterized in that: include: one or more processors; a memory for storing one or more programs; Among them, when one or more programs are executed by the one or more processors, the one or more processors implement a method for determining the coding accuracy and update period of satellite clock and orbit correction product integrity information as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that Executable instructions are stored thereon, which, when executed by a processor, enable the processor to implement a method for determining the coding accuracy and update period of satellite clock and orbit correction product integrity information as described in any one of claims 1-7.

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