Quality evaluation method and quality evaluation device for troposphere moisture delay correction product

Abstract

The invention discloses a troposphere moisture delay correction product quality evaluation method and a quality evaluation device, the troposphere moisture delay (ZWD) estimation value of each monitoring station is independently calculated, the effective ZWD estimation value is judged from an observation domain and a positioning domain, and the quality of the ZWD estimation value is improved; an effective ZWD estimated value is judged from a positioning domain and directly corresponds to a user demand, so that the accuracy of fault identification is improved; a ZWD interpolation result is calculated through an effective ZWD estimated value, a ZWD residual error is calculated based on the interpolation result and a ZWD correction product, the quality of the ZWD correction product is evaluated according to the ZWD residual error in combination with the number of effective monitoring stations, a terminal user can reject unavailable and low-quality ZWD correction products according to a quality evaluation result, and information support is provided for improving decision quality and safety for the user. The external coincidence precision based on the monitoring station is obtained through quality evaluation, the real error of the ZWD correction product is reflected more accurately, and the influence of the ZWD correction product on the reliability and accuracy of the positioning result is reduced.

Description

Technical Field

[0001] The present invention relates to satellite navigation technology, and in particular to a quality assessment method and a quality assessment device for tropospheric wet delay correction products. Background Art

[0002] The Global Navigation Satellite System (GNSS) can provide global users with three-dimensional, all-weather, high-quality positioning, navigation and timing (PNT) services, and is a critical positioning method for industries such as transportation, communications, and surveying and mapping. However, the use of GNSS's own navigation service can only achieve meter-level positioning accuracy, which cannot meet the urgent needs for fast centimeter-level positioning in fields such as autonomous driving, precision agriculture, drone mapping, geodesy, and earthquake and tsunami monitoring; for this reason, high-precision positioning technology based on GNSS has emerged. Typical high-precision positioning methods include real-time kinematic (RTK), precise point positioning (PPP), and PPP-RTK, which combines the advantages of both PPP and RTK. The basic idea of ​​PPP-RTK is to use the local area network observation data to refine the (partial) state space domain correction (SSR, State Space Representation) products provided by the global network (wide area network), such as satellite orbit clock errors, and solve parameters such as atmospheric delay. All kinds of regenerated correction information are represented by SSR and broadcast separately to the mobile station for use; the user end uses the received SSR correction number to correct the observation data to restore the integer characteristics of the ambiguity and fix it, and achieve high-precision positioning at the decimeter level or even the centimeter level by accelerating the initialization of PPP.

[0003] As an important high-precision atmospheric prior constraint in the correction of SSR products, the correction of tropospheric wet delay (ZWD) can greatly shorten the time of PPP convergence and improve the user positioning experience. Since the tropospheric delay has significant temporal and spatial correlation, the ZWD correction in related technologies is usually calculated by region. The steps of calculating the ZWD correction in a region include: 1. Data collection: Collect observation data from ground observation stations evenly distributed in the region to ensure that the data density and quality within the coverage meet the requirements; 2. PPP processing: When the data density and quality within the coverage meet the requirements, the data of each reference station is processed by precise point positioning (PPP) to obtain a high-precision ZWD reference estimate. This step is the basis for ensuring the accuracy of subsequent interpolation; 3. Spatial interpolation: Apply appropriate spatial interpolation algorithms (such as kriging, inverse distance weighted method, etc.) to estimate the ZWD correction (ZWD correction product) of any point in the region based on the ZWD reference estimate of each reference station; when selecting the interpolation method, its applicability and accuracy should be considered to achieve the best spatial prediction effect. Although the Kriging interpolation method can provide the model strength (or internal accuracy) of the interpolation results, it cannot fully reflect the true estimation error of the interpolation results.

[0004] In GNSS applications, especially in the field of high-precision positioning services, the accuracy of ZWD corrections has a direct impact on the final positioning results; related technologies The methods for calculating ZWD corrections usually rely on interpolation techniques, which can provide model strength under certain conditions; however, the obtained ZWD corrections still have some significant shortcomings, which may affect their reliability and accuracy in practical applications; including: 1. Inability to reflect the true error: only the internal consistency of the model is evaluated, that is, the degree of agreement between the observed value and the model prediction value (the model here refers to the model used to estimate position, clock error and other parameters in GNSS positioning), and it cannot directly reflect the difference between the model prediction value and the real physical phenomenon; this means that even if a model exhibits high internal consistency accuracy, its prediction results may systematically deviate from the actual situation. 2. It is difficult to identify model defects. It is difficult to discover and diagnose potential problems or limitations in the model. The reasons include: I. It only relies on internal accuracy. Internal accuracy depends on the assumptions of the model, such as the distribution characteristics of observation errors. If these assumptions are not true, then even if the model shows good internal consistency, it may not correctly reflect the actual error. II. Systematic deviations: If there are factors that are not considered by the model, such as atmospheric delay and satellite orbit errors, these systematic deviations will not be captured by internal accuracy because they also affect all observations, resulting in consistent deviations in the entire data set, which does not affect internal accuracy. III. Lack of external reference: Internal accuracy is based on the performance of the model itself, not relative to a known true value or an independent external reference system. Therefore, even if the model is very consistent internally, its absolute accuracy cannot be guaranteed. IV. The impact of random errors: Even if the model is very good, random errors will cause the results of a single measurement to deviate from the true value. The existence of such random errors makes even highly accurate models likely to have large residuals. 3. Difficulty in terminal integration: For end users, only knowing the internal accuracy is not enough for them to fully trust the correction service they use.

[0005] In summary, how to reduce the defects of ZWD correction numbers and avoid them affecting the reliability and accuracy of positioning results in practical applications has become a problem to be solved. Summary of the invention

[0006] The embodiment of the present application provides a quality assessment method for a tropospheric wet delay correction product, comprising: For two or more monitoring stations set in advance, the corresponding tropospheric wet delay ZWD estimation value and the monitoring station coordinate position of each monitoring station at the first moment are determined respectively, wherein the two or more monitoring stations are evenly distributed in the area where the reference station is located, the reference station is a base station on a preset grid point, the preset grid point is the grid point for calculating the ZWD correction product, and the first moment is the moment for calculating the ZWD correction product; For each ZWD estimation value obtained, the validity of the ZWD estimation value is judged by the posterior residual, posterior variance and position domain check respectively. The posterior residual is used to determine whether the ZWD estimation value is valid based on the observed data, the posterior variance is used to determine whether the ZWD estimation value is valid based on the statistical characteristics of multiple ZWD estimation values, and the position domain check is used to determine whether the ZWD estimation value is valid based on the obtained monitoring station coordinate position and the actual coordinates of the monitoring station; Calculate the ZWD interpolation result at each preset grid point according to the ZWD estimated value determined to be valid; For each grid point, the ZWD residual of the grid point at the first moment is determined based on the ZWD interpolation result of each grid point and the ZWD correction product at the first moment; The quality of the ZWD correction product of each grid point is evaluated based on the statistical characteristics of the ZWD residuals of all grid points in a time sliding window of preset length and the number of valid monitoring stations contained in the area where the reference station is located. The valid monitoring station is the monitoring station corresponding to the valid ZWD estimate.

[0007] On the other hand, an embodiment of the present application further provides a computer storage medium, wherein the computer storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned quality assessment method is implemented.

[0008] On the other hand, an embodiment of the present application further provides a terminal, comprising: a memory and a processor, wherein the memory stores a computer program; wherein: The processor is configured to execute the computer program in the memory; When the computer program is executed by the processor, the quality assessment method described above is implemented.

[0009] In another aspect, the embodiment of the present application further provides a quality assessment device for a tropospheric wet delay correction product, comprising: an estimation value determination unit, a validity determination unit, an interpolation unit, a residual determination unit and a quality assessment unit; wherein, The estimation value determination unit is configured to: for two or more preset monitoring stations, respectively determine the tropospheric wet delay ZWD estimation value and the monitoring station coordinate position corresponding to each monitoring station at the first moment, wherein the two or more monitoring stations are evenly distributed in the area where the reference station is located, the reference station is a base station on a preset grid point, the preset grid point is a grid point for calculating the ZWD correction product, and the first moment is the moment for calculating the ZWD correction product; The validity determination unit is configured to: for each ZWD estimation value obtained, determine whether the ZWD estimation value is valid through the posterior residual, the posterior variance and the position domain check respectively, wherein the posterior residual is used to determine whether the ZWD estimation value is valid based on the observed data, the posterior variance is used to determine whether the ZWD estimation value is valid based on the statistical characteristics of multiple ZWD estimation values, and the position domain check is used to determine whether the ZWD estimation value is valid based on the obtained monitoring station coordinate position and the actual coordinates of the monitoring station; The interpolation unit is set to: calculate the ZWD interpolation result at each preset grid point according to the ZWD estimation value judged to be valid; The residual unit setting is determined as follows: for each grid point, the ZWD residual of the grid point at the first moment is determined according to the ZWD interpolation result of each grid point and the ZWD correction product at the first moment; The quality assessment unit is set to evaluate the quality of the ZWD correction product of each grid point according to the statistical characteristics of the ZWD residuals of all grid points in a time sliding window of preset length and the number of valid monitoring stations contained in the area where the reference station is located, where the valid monitoring station is the monitoring station corresponding to the valid ZWD estimation value.

[0010] The disclosed embodiment independently calculates the ZWD estimation value of each monitoring station, and judges the effective ZWD estimation value from the observation domain and positioning domain levels through the three aspects of post-validation residual, post-validation variance and location domain verification, thereby improving the use quality of the ZWD estimation value and enhancing the integrity of the entire system and the reliability of the link; based on the location domain verification, the effective ZWD estimation value is judged from the positioning domain level, which directly corresponds to the actual needs of the user, improves the accuracy of fault identification, ensures that the results output by the system are closer to the user's application scenario, and improves the user experience and satisfaction; the ZWD interpolation result is calculated through the effective ZWD estimation value, and the ZWD residual calculated based on the interpolation result and the ZWD correction product is combined with the ZWD residual of the grid point in the time sliding window with the number of effective monitoring stations to calculate the ZWD interpolation, which well evaluates the ZWD spatial accuracy, and the grid points in the time sliding window of preset duration are The statistical characteristics of the ZWD residuals can well evaluate the ZWD time accuracy. The evaluation process integrates the spatial and temporal characteristics of the ZWD correction products, improves the efficiency of data processing and fusion, and realizes the quality evaluation of the ZWD correction products based on the monitoring station. The end users can eliminate unusable and low-quality ZWD correction products according to the quality evaluation results, eliminate the risks brought by potential failures, and provide information support for users to improve the quality and safety of decision-making; the external conformity accuracy based on the monitoring station is obtained through quality evaluation. Compared with the internal conformity accuracy that only relies on the internal consistency of the model, it more accurately reflects the real error of the ZWD correction product and has higher reliability. It provides data for users to conduct quality control of the ZWD correction products, reduces the impact of the ZWD correction products on the reliability and accuracy of the positioning results, and provides data support for improving the positioning accuracy and reliability of user terminals.

[0011] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0013] Figure 1 A flow chart of a quality assessment method for tropospheric wet delay correction products according to an embodiment of the present disclosure; Figure 2 It is a structural block diagram of the quality assessment device of the tropospheric wet delay correction product according to the embodiment of the present disclosure. DETAILED DESCRIPTION

[0014] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0015] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0016] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0017] Figure 1 Flow chart of the quality assessment method of the tropospheric wet delay correction product according to the embodiment of the present disclosure. Figure 1 As shown, including: Step 101, for two or more pre-set monitoring stations, respectively determine the corresponding tropospheric wet delay (ZWD) estimation value and the monitoring station coordinate position of each monitoring station at the first moment, wherein the two or more monitoring stations are evenly distributed in the area where the reference station is located, the reference station is a base station on a preset grid point, the preset grid point is the grid point for calculating the ZWD correction product, and the first moment is the moment for calculating the ZWD correction product; Step 102: for each ZWD estimation value obtained, determine whether the ZWD estimation value is valid through posterior residual, posterior variance and position domain check respectively, wherein the posterior residual is used to determine whether the ZWD estimation value is valid based on the observed data, the posterior variance is used to determine whether the ZWD estimation value is valid based on the statistical characteristics of multiple ZWD estimation values, and the position domain check is used to determine whether the ZWD estimation value is valid based on the obtained monitoring station coordinate position and the actual coordinates of the monitoring station; Step 103: Calculate the ZWD interpolation result at each preset grid point according to the ZWD estimated value determined to be valid; Step 104: for each grid point, determine the ZWD residual of the grid point at the first moment according to the ZWD interpolation result of each grid point and the ZWD correction product at the first moment; Step 105: Evaluate the quality of the ZWD correction product of each grid point according to the statistical characteristics of the ZWD residuals of all grid points within a time sliding window of a preset length and the number of valid monitoring stations contained in the area where the reference station is located, wherein the valid monitoring station is the monitoring station corresponding to the valid ZWD estimation value.

[0018] The disclosed embodiment independently calculates the ZWD estimation value of each monitoring station, and judges the effective ZWD estimation value from the observation domain and positioning domain levels through the three aspects of post-validation residual, post-validation variance and location domain verification, thereby improving the use quality of the ZWD estimation value and enhancing the integrity of the entire system and the reliability of the link; based on the location domain verification, the effective ZWD estimation value is judged from the positioning domain level, which directly corresponds to the actual needs of the user, improves the accuracy of fault identification, ensures that the results output by the system are closer to the user's application scenario, and improves the user experience and satisfaction; the ZWD interpolation result is calculated through the effective ZWD estimation value, and the ZWD residual calculated based on the interpolation result and the ZWD correction product is combined with the ZWD residual of the grid point in the time sliding window with the number of effective monitoring stations to calculate the ZWD interpolation, which well evaluates the ZWD spatial accuracy, and the grid points in the time sliding window of preset duration are The statistical characteristics of the ZWD residuals can well evaluate the ZWD time accuracy. The evaluation process integrates the spatial and temporal characteristics of the ZWD correction products, improves the efficiency of data processing and fusion, and realizes the quality evaluation of the ZWD correction products based on the monitoring station. The end users can eliminate unusable and low-quality ZWD correction products according to the quality evaluation results, eliminate the risks brought by potential failures, and provide information support for users to improve the quality and safety of decision-making; the external conformity accuracy based on the monitoring station is obtained through quality evaluation. Compared with the internal conformity accuracy that only relies on the internal consistency of the model, it more accurately reflects the real error of the ZWD correction product and has higher reliability. It provides data for users to conduct quality control of the ZWD correction products, reduces the impact of the ZWD correction products on the reliability and accuracy of the positioning results, and provides data support for improving the positioning accuracy and reliability of user terminals.

[0019] The disclosed embodiments detect and eliminate the ZWD estimation values ​​of faulty monitoring stations from three different dimensions; among them, post-test residual elimination: preliminarily judge whether there is an abnormality by directly checking the observation residuals of pseudorange and carrier phase; post-test variance elimination: evaluate the quality of ZWD estimation values ​​based on the statistical characteristics of multiple ZWD estimation values, which considers the uncertainty of parameter estimation rather than the difference of single observation values; position domain verification: verify the validity of the result by comparing the difference between the solved position and the known true value.

[0020] The ZWD residual in the embodiments of the present disclosure represents the difference between the ZWD estimate and the ZWD correction product.

[0021] In an exemplary embodiment, the number of monitoring stations in the embodiment of the present disclosure is greater than or equal to one third of the number of reference stations in the area.

[0022] In an exemplary embodiment, the embodiment of the present disclosure uses dual-frequency ionosphere-free (IF, Ionosphere-Free) PPP for state estimation based on the need to monitor ZWD correction products. The IF-PPP observation equation is as follows: Where s and r represent the satellite and receiver respectively, and IF represents that the physical quantity is in the form of ionosphere-free combination. and They are the observation minus computation (OMC) of pseudorange and carrier respectively. represents the direction cosine of the line connecting the satellite and the receiver, x is the three-dimensional position increment, and Identify the receiver and satellite clock errors respectively, is the zenith tropospheric wet delay, is the corresponding wet projection function, is the carrier wavelength, is the carrier phase integer ambiguity, d and b represent the pseudorange hardware delay and carrier hardware delay respectively, and denote the observation noise and multipath error combination of pseudorange and carrier, respectively.

[0023] The disclosed embodiment integrates more information for monitoring ZWD correction products by using a dual detector constructed by using pseudorange residuals and carrier phase residuals of the IF-PPP floating point solution.

[0024] In an exemplary embodiment, the embodiment of the present disclosure performs PPP calculations on two or more pre-set monitoring stations respectively to obtain the ZWD estimation value and the monitoring station coordinate position corresponding to each independent monitoring station at the first moment.

[0025] In an exemplary embodiment, the embodiment of the present disclosure performs PPP calculation on two or more pre-set monitoring stations based on pseudorange and carrier data at the first moment to obtain the corresponding ZWD estimation value and monitoring station coordinate position of each independent monitoring station at the first moment.

[0026] In an exemplary embodiment, the method of the present disclosure further includes: For each grid point, the root mean square error between the ZWD correction product of the grid point and all ZWD residuals in the time sliding window is calculated, and the root mean square error is used as the quality factor (QI) to determine the quality of the correction product.

[0027] The disclosed embodiment directly measures the difference between the ZWD correction product and the actual observation through the quality factor, so that the user can more accurately understand the true error range of the correction product; the obtained quality factor provides a clear data quality judgment standard for the correction product, which can facilitate the server to identify and improve model defects; the user can calculate a more accurate and reliable tropospheric correction value based on the quality factor, reducing the positioning problems caused by the anomaly of the ZWD correction product and improving the reliability and security of the positioning results. After the disclosed embodiment obtains the quality factor, the terminal user can reasonably weight the ZWD correction product at each grid point involved in the solution according to the quality factor and perform positioning solution, thereby improving the reliability and security of the positioning results.

[0028] In an exemplary embodiment, the embodiment of the present disclosure evaluates the quality of the ZWD correction product of each grid point according to the statistical characteristics of the ZWD residuals of all grid points within a time sliding window of a preset length and the number of valid monitoring stations contained in the area where the reference station is located, including: When the number of valid monitoring stations in the region is greater than a preset threshold of the number of valid monitoring stations (for example, five, the quality requirements of the correction product can be set according to the number of monitoring stations in the region and the application scenario), and the ZWD residual of the grid point is less than the preset residual threshold, the quality of the ZWD correction product of the grid point is determined to be normal; The residual threshold of the embodiment of the present disclosure may be related to the statistical characteristics of all ZWD residuals in the time sliding window corresponding to the current grid point (for example, the mean or variance of the ZWD residuals); when the quality of the ZWD corrected product of the embodiment of the present disclosure is normal, it means that the ZWD corrected product has no faults and can be used; When the number of valid monitoring stations in the area is greater than the threshold of the number of valid monitoring stations, and the ZWD residual of the grid point is greater than or equal to the residual threshold, the quality alarm of the ZWD correction product of the grid point is determined; when the ZWD correction product of the embodiment of the present disclosure is a quality alarm, it means that the ZWD correction product is faulty and unavailable; If the number of valid monitoring stations in the area is less than or equal to the threshold of the number of valid monitoring stations, it is determined that the quality of the ZWD correction product at the grid point is not monitored; when the quality of the ZWD correction product in the embodiment of the present disclosure is not monitored, it means that the fault of the ZWD correction product is unknown.

[0029] In an exemplary embodiment, the method of the present disclosure further includes: When the ZWD correction product of a grid point is not obtained due to information encoding and decoding errors, it is determined that the monitoring information of the ZWD correction product of the grid point is abnormal.

[0030] In an exemplary embodiment, the method of the embodiment of the present disclosure further includes: adding a corresponding quality mark for the quality of the ZWD correction product of each grid point evaluated.

[0031] The disclosed embodiment defines the quality of the ZWD correction product for each grid point, adds a quality mark according to the quality result of the evaluation, can clearly display the health status of the ZWD correction product for each grid point, and alarm the grid point with a fault, so that the quality information of the ZWD correction product obtained by evaluation is clear and easy to use, which simplifies the gross error elimination operation of the ZWD correction product of the user terminal; the user can more conveniently manage and use the ZWD correction product based on the quality evaluation, thereby improving the user's decision-making efficiency.

[0032] The disclosed embodiment directly measures the difference between the ZWD correction product and the actual observation through the quality factor, so that the user can more accurately understand the true error range of the correction product; secondly, the available identification and quality factor provide a clear data quality judgment standard for the correction number, which can facilitate the service end to identify and improve model defects; finally, after receiving the external accuracy, the disclosed embodiment provides the QI information of the ZWD data without fault in real time, so that the user can calculate more accurate and reliable tropospheric correction values. The positioning problems caused by the abnormality of the ZWD correction number product are reduced, and the reliability and security of the positioning results are improved.

[0033] In the application field of high-precision GNSS (such as autonomous vehicles and eVTOL), the ZWD correction product with quality factor and quality mark in the embodiment of the present disclosure plays a vital role, including: 1. Improving positioning accuracy: The atmospheric product correction number containing the ZWD correction product in the embodiment of the present disclosure can effectively compensate for the influence of the atmosphere on the propagation of GNSS signals, such as ionospheric delay and tropospheric delay; the application of these correction numbers significantly improves the accuracy and convergence time of GNSS positioning, which means more accurate vehicle position and heading information for autonomous vehicles; 2. Enhancing system reliability: The quality mark and quality factor information ensure the accuracy and reliability of the ZWD correction product; in the autonomous driving system, the real-time monitoring and evaluation of this information is the key to ensuring the safe driving of the vehicle; 3. Meeting regulatory requirements: The ZWD correction product with quality mark and quality factor information can help the positioning system meet the strict requirements of relevant standards for accuracy and reliability, which is crucial to promoting the commercialization of autonomous driving technology.

[0034] The embodiment of the present disclosure also provides a computer storage medium, in which a computer program is stored. When the computer program is executed by a processor, the quality assessment method of the tropospheric wet delay correction product is implemented.

[0035] The embodiment of the present disclosure further provides a terminal, comprising: a memory and a processor, wherein a computer program is stored in the memory; The processor is configured to execute the computer program in the memory; When the computer program is executed by a processor, the quality assessment method of the tropospheric wet delay correction product as described above is implemented.

[0036] Figure 2 : is a structural block diagram of a quality assessment device for tropospheric wet delay correction products according to an embodiment of the present disclosure, such as Figure 2 As shown, it includes: an estimated value determination unit, a validity determination unit, an interpolation unit, a residual determination unit and a quality assessment unit; wherein, The estimation value determination unit is configured to: for two or more preset monitoring stations, respectively determine the tropospheric wet delay ZWD estimation value and the monitoring station coordinate position corresponding to each monitoring station at the first moment, wherein the two or more monitoring stations are evenly distributed in the area where the reference station is located, the reference station is a base station on a preset grid point, the preset grid point is a grid point for calculating the ZWD correction product, and the first moment is the moment for calculating the ZWD correction product; The validity determination unit is configured to: for each ZWD estimation value obtained, determine whether the ZWD estimation value is valid through the posterior residual, the posterior variance and the position domain check respectively, wherein the posterior residual is used to determine whether the ZWD estimation value is valid based on the observed data, the posterior variance is used to determine whether the ZWD estimation value is valid based on the statistical characteristics of multiple ZWD estimation values, and the position domain check is used to determine whether the ZWD estimation value is valid based on the obtained monitoring station coordinate position and the actual coordinates of the monitoring station; The interpolation unit is set to: calculate the ZWD interpolation result at each preset grid point according to the ZWD estimation value judged to be valid; The residual unit setting is determined as follows: for each grid point, the ZWD residual of the grid point at the first moment is determined according to the ZWD interpolation result of each grid point and the ZWD correction product at the first moment; The quality assessment unit is set to evaluate the quality of the ZWD correction product of each grid point according to the statistical characteristics of the ZWD residuals of all grid points in a time sliding window of preset length and the number of valid monitoring stations contained in the area where the reference station is located, where the valid monitoring station is the monitoring station corresponding to the valid ZWD estimation value.

[0037] In an exemplary embodiment, the number of monitoring stations in the embodiment of the present disclosure is greater than or equal to one third of the number of reference stations in the area.

[0038] In an exemplary embodiment, the estimated value determination unit of the embodiment of the present disclosure is configured as follows: PPP calculations are performed on two or more pre-set monitoring stations to obtain the corresponding ZWD estimation value and monitoring station coordinate position of each independent monitoring station at the first moment.

[0039] In an exemplary embodiment, the quality assessment device of the embodiment of the present disclosure further includes a quality factor determination unit, which is configured as follows: For each grid point, the root mean square error between the ZWD correction product of the grid point and all ZWD residuals in the time sliding window is calculated, and the root mean square error is used as the quality factor (QI) to determine the quality of the correction product.

[0040] In an exemplary embodiment, the quality assessment unit of the embodiment of the present disclosure is configured as follows: When the number of valid monitoring stations in the region is greater than a preset threshold of the number of valid monitoring stations (for example, five, the quality requirements of the correction product can be set according to the number of monitoring stations in the region and the application scenario), and the ZWD residual of the grid point is less than the preset residual threshold, the quality of the ZWD correction product of the grid point is determined to be normal; The residual threshold of the embodiment of the present disclosure may be related to the statistical characteristics of all ZWD residuals in the time sliding window corresponding to the current grid point (for example, the mean or variance of the ZWD residuals); when the quality of the ZWD corrected product of the embodiment of the present disclosure is normal, it means that the ZWD corrected product has no faults and can be used; When the number of valid monitoring stations in the area is greater than the threshold of the number of valid monitoring stations, and the ZWD residual of the grid point is greater than or equal to the residual threshold, the quality alarm of the ZWD correction product of the grid point is determined; when the ZWD correction product of the embodiment of the present disclosure is a quality alarm, it means that the ZWD correction product is faulty and unavailable; If the number of valid monitoring stations in the area is less than or equal to the threshold of the number of valid monitoring stations, it is determined that the quality of the ZWD correction product at the grid point is not monitored; when the quality of the ZWD correction product in the embodiment of the present disclosure is not monitored, it means that the fault of the ZWD correction product is unknown.

[0041] In an exemplary embodiment, the quality assessment unit of the embodiment of the present disclosure is further configured to: When the ZWD correction product of a grid point is not obtained due to information encoding and decoding errors, the quality of the ZWD correction product of the grid point is determined to be abnormal monitoring information.

[0042] In an exemplary embodiment, the quality assessment unit of the embodiment of the present disclosure is further configured to: Add a corresponding quality mark to the quality of the ZWD correction product for each grid point evaluated.

[0043] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or transient medium). As is known to those skilled in the art, the term "computer storage medium" includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A method for evaluating the quality of tropospheric wet delay correction products, characterized in that: include: For two or more monitoring stations set in advance, the corresponding tropospheric wet delay ZWD estimation value and the monitoring station coordinate position of each monitoring station at the first moment are determined respectively, wherein the two or more monitoring stations are evenly distributed in the area where the reference station is located, the reference station is a base station on a preset grid point, the preset grid point is the grid point for calculating the ZWD correction product, and the first moment is the moment for calculating the ZWD correction product; For each ZWD estimation value obtained, the validity of the ZWD estimation value is judged by the posterior residual, posterior variance and position domain check respectively. The posterior residual is used to determine whether the ZWD estimation value is valid based on the observed data, the posterior variance is used to determine whether the ZWD estimation value is valid based on the statistical characteristics of multiple ZWD estimation values, and the position domain check is used to determine whether the ZWD estimation value is valid based on the obtained monitoring station coordinate position and the actual coordinates of the monitoring station; Calculate the ZWD interpolation result at each preset grid point according to the ZWD estimated value determined to be valid; For each grid point, the ZWD residual of the grid point at the first moment is determined based on the ZWD interpolation result of each grid point and the ZWD correction product at the first moment; The quality of the ZWD correction product of each grid point is evaluated based on the statistical characteristics of the ZWD residuals of all grid points in a time sliding window of preset length and the number of valid monitoring stations contained in the area where the reference station is located. The valid monitoring station is the monitoring station corresponding to the valid ZWD estimate.

2. The quality assessment method according to claim 1, characterized in that: The number of monitoring stations is greater than or equal to one third of the number of reference stations in the region.

3. The quality assessment method according to claim 1, characterized in that: The step of respectively determining the tropospheric wet delay ZWD estimation value and the coordinate position of each monitoring station corresponding to the first moment comprises: Precise point positioning (PPP) calculations are performed on two or more pre-set monitoring stations to obtain a corresponding ZWD estimation value and a monitoring station coordinate position of each independent monitoring station at the first moment.

4. The quality assessment method according to any one of claims 1 to 3, characterized in that: After determining the ZWD residual of the grid point at the first moment, the method further includes: For each grid point, the root mean square error between the ZWD correction product of the grid point and all ZWD residuals in the time sliding window is calculated, and the root mean square error is used as the quality factor QI to determine the quality of the ZWD correction product.

5. The quality assessment method according to any one of claims 1 to 3, characterized in that: The quality of the ZWD correction product of each grid point is evaluated according to the statistical characteristics of the ZWD residuals of all grid points in the time sliding window of the preset time length and the number of valid monitoring stations contained in the area where the reference station is located, including: When the number of effective monitoring stations in the area is greater than a preset threshold of the number of effective monitoring stations, and the ZWD residual of the grid point is less than a preset residual threshold, it is determined that the quality of the ZWD correction product of the grid point is normal; When the number of valid monitoring stations in the area is greater than the threshold of the number of valid monitoring stations, and the ZWD residual of the grid point is greater than or equal to the residual threshold, a quality alarm of the ZWD correction product of the grid point is determined; The number of valid monitoring stations in the area is less than or equal to the threshold of the number of valid monitoring stations, and it is determined that the quality of the ZWD correction product of the grid point is not monitored.

6. The quality assessment method according to claim 5, characterized in that: According to the statistical characteristics of the ZWD residuals of all grid points in the time sliding window of the preset duration and the number of valid monitoring stations contained in the area where the reference station is located, the quality of the ZWD correction product of each grid point is evaluated respectively, and the method further comprises: When the ZWD correction product of a grid point is not obtained due to information encoding and decoding errors, the quality of the ZWD correction product of the grid point is determined to be abnormal monitoring information.

7. The quality assessment method according to claim 6, characterized in that: After evaluating the quality of the ZWD correction product of each grid point according to the statistical characteristics of the ZWD residuals of all grid points in the time sliding window of the preset duration and the number of valid monitoring stations contained in the area where the reference station is located, the method further includes: Add a corresponding quality mark to the quality of the ZWD correction product for each grid point evaluated.

8. A computer storage medium, wherein a computer program is stored in the computer storage medium, and when the computer program is executed by a processor, the quality assessment method according to any one of claims 1 to 7 is implemented.

9. A terminal, comprising: A memory and a processor, wherein the memory stores a computer program; wherein, The processor is configured to execute the computer program in the memory; When the computer program is executed by the processor, the quality assessment method according to any one of claims 1 to 7 is implemented.

10. A quality assessment device for tropospheric wet delay correction products, comprising: An estimated value determination unit, a validity determination unit, an interpolation unit, a residual determination unit and a quality assessment unit; wherein, The estimation value determination unit is configured to: for two or more preset monitoring stations, respectively determine the tropospheric wet delay ZWD estimation value and the monitoring station coordinate position corresponding to each monitoring station at the first moment, wherein the two or more monitoring stations are evenly distributed in the area where the reference station is located, the reference station is a base station on a preset grid point, the preset grid point is a grid point for calculating the ZWD correction product, and the first moment is the moment for calculating the ZWD correction product; The validity determination unit is configured to: for each ZWD estimation value obtained, determine whether the ZWD estimation value is valid through the posterior residual, the posterior variance and the position domain check respectively, wherein the posterior residual is used to determine whether the ZWD estimation value is valid based on the observed data, the posterior variance is used to determine whether the ZWD estimation value is valid based on the statistical characteristics of multiple ZWD estimation values, and the position domain check is used to determine whether the ZWD estimation value is valid based on the obtained monitoring station coordinate position and the actual coordinates of the monitoring station; The interpolation unit is set to: calculate the ZWD interpolation result at each preset grid point according to the ZWD estimation value judged to be valid; The residual unit setting is determined as follows: for each grid point, the ZWD residual of the grid point at the first moment is determined according to the ZWD interpolation result of each grid point and the ZWD correction product at the first moment; The quality assessment unit is set to evaluate the quality of the ZWD correction product of each grid point according to the statistical characteristics of the ZWD residuals of all grid points in a time sliding window of preset length and the number of valid monitoring stations contained in the area where the reference station is located, where the valid monitoring station is the monitoring station corresponding to the valid ZWD estimation value.

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