A positioning method, system, device, and medium
By constructing an ionospheric correction model for multiple target base station sets and performing weighted fusion, the problem of providing reliable and high-precision ionospheric correction services for off-network users in the CORS system was solved, and high-precision positioning of off-network users was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-26
- Publication Date
- 2026-06-23
AI Technical Summary
The BeiDou Ground-Based Augmentation System (CORS) is unable to provide reliable and high-precision ionospheric correction services to users outside the network, resulting in low positioning accuracy and poor reliability outside the network.
By identifying multiple target base station sets, an ionospheric correction model is constructed, an initial ionospheric correction number is calculated, and the reliability of the model is evaluated using weighted fusion and error propagation equations. Correction services are only provided when the results of multiple models are consistent.
It enables high-precision positioning of users outside the network, improves the reliability and accuracy of ionospheric correction services, and ensures the credibility and accuracy of positioning results.
Smart Images
Figure CN122260362A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of satellite positioning, and more particularly to a positioning method, system, device, and medium. Background Technology
[0002] The BeiDou Ground-Based Augmentation System (CORS) provides centimeter-level positioning services to users within the network through multiple base stations, but the service range is limited by the physical network coverage of the base stations, making it difficult to meet the high-precision requirements of areas outside the network.
[0003] Currently, users outside the network typically locate themselves by obtaining raw observation data from the nearest single base station. The system cannot generate and provide reliable, high-precision ionospheric correction services for these users. However, due to the significant spatial variation in ionospheric delay, the extrapolation error of single-station data is large and cannot be verified, resulting in low positioning accuracy and poor reliability outside the network. Summary of the Invention
[0004] This invention provides a positioning method, system, device, and medium that can solve the problem of how to enable the CORS system to provide reliable and high-precision ionospheric correction services to users outside the network, so that users outside the network can also achieve high-precision positioning based on the CORS system's base stations.
[0005] This invention provides a positioning method, comprising: Based on the initial location information of users outside the network, multiple target base station sets are determined from all the first base stations of the BeiDou ground-based augmentation system. The users outside the network refer to users outside the preset service range of the BeiDou ground-based augmentation system. For each set of target base stations, an ionospheric correction model is determined based on the base station observation data of all target base stations, and the initial ionospheric correction number between the external user and the target satellite is determined based on the ionospheric correction model. Calculate the pairwise differences between all the initial ionospheric corrections to obtain the maximum difference, and compare the maximum difference with a preset threshold. If the maximum difference is less than or equal to a preset threshold, the initial ionospheric corrections are fused to obtain a target ionospheric correction. The target ionospheric correction is then sent to the off-network user so that the off-network user can perform positioning calculations based on the target ionospheric correction and the off-network user's original observation data to obtain the target location information.
[0006] This invention determines multiple target base station sets based on the initial location information of users outside the network, expanding the scope of the correction service beyond a single user within the network and providing a foundation for subsequent multi-model analysis. For each set, an ionospheric correction model is determined and initial corrections are calculated. Ionospheric errors are evaluated from different spatial perspectives using multiple independent models, improving the comprehensiveness of the evaluation. A cross-validation mechanism is introduced, comparing the maximum difference between all corrections with a preset threshold, automatically determining the reliability of the model results and preventing unreliable corrections from affecting positioning. When the maximum difference is less than or equal to the threshold, the corrections are fused and sent to the user, ensuring that enhanced services are only provided when the results of multiple models are consistent, thus improving the reliability of the corrections. Users are then positioned based on the corrections and original observation data, extending the correction service from within the network to outside the network and achieving high-precision positioning for users outside the network.
[0007] Furthermore, the determination of multiple target base station sets from all first base stations of the BeiDou ground-based augmentation system based on the initial location information of users outside the network specifically involves: Among all the first base stations, a main base station and multiple second base stations are determined based on initial location information. The main base station is the first base station that is closest to the user outside the network, and each of the second base stations is a first base station whose distance from the main base station is within a preset range. Based on the main base station and all the second base stations, a first preset number of target base station sets is determined.
[0008] This invention, through its embodiments, determines the base station closest to the user as the primary base station, ensuring that the extrapolation starting point is closest to the user, minimizing the spatial extrapolation distance, and reducing extrapolation errors. It selects a second base station within a preset distance from the primary base station to ensure a reasonable spatial distribution of base stations participating in the modeling, guaranteeing ionospheric spatial correlation and improving model effectiveness. Based on the primary and second base stations, it determines a target set, forming a user-centric local modeling region, making the model more targeted. Overall, this lays a spatial foundation for constructing a high-quality ionospheric correction model and effectively controls the uncertainty of model extrapolation.
[0009] Further, the step of determining a first preset number of target base station sets based on the initial location information, based on the main base station and all the second base stations, specifically involves: From all the second base stations, a first preset number of initial base station sets are randomly selected, wherein the initial base station set includes a second preset number of second base stations; The main base station is combined with each of the initial base station sets to obtain each of the target base station sets.
[0010] In this embodiment of the invention, an initial set of base stations is randomly selected from the second base stations to ensure that multiple models have different spatial sampling points; each set contains a specific number of second base stations to control the complexity of each model and avoid overfitting or underfitting; the main base station is combined with each initial set to achieve the differential construction of multiple models while ensuring that all models contain the nearest reference point and maintain extrapolation consistency.
[0011] Furthermore, the base station observation data includes carrier phase values and pseudorange observation values. Specifically, for each set of target base stations, determining the ionospheric correction model based on the base station observation data of all target base stations involves: The ionospheric delay of each target base station relative to the target satellite is calculated based on the carrier phase value and the pseudorange observation value of each target base station. The ionospheric delay is processed by linear interpolation to obtain the ionospheric correction model corresponding to the target base station set.
[0012] This invention calculates the ionospheric delay of each base station to obtain the original observed values of ionospheric error, providing a data foundation for modeling; it uses linear interpolation to process the delay data, constructs a simple and effective spatial variation model, has high computational efficiency, and is suitable for real-time applications.
[0013] Furthermore, the process of fusing the initial ionospheric corrections to obtain the target ionospheric correction specifically involves: The interpolation error of each ionospheric correction model is calculated based on the error propagation equation, and the weights corresponding to each initial ionospheric correction number are determined based on each interpolation error. The initial ionospheric corrections are weighted and fused according to their respective weights to obtain the target ionospheric correction.
[0014] This invention calculates the interpolation error of each model to quantitatively evaluate the theoretical accuracy of each model at the extrapolation point; determines the weights based on the interpolation error to achieve intelligent weighting of high-precision models with high weights and low-precision models with low weights; and obtains the target correction number through weighted fusion, which can combine the advantages of multiple models to obtain a better result than any single model, achieving optimal fusion based on accuracy and significantly improving the accuracy and reliability of the final correction number.
[0015] Furthermore, the interpolation error of each ionospheric correction model calculated based on the error propagation equation is specifically as follows: For each target base station, based on the ionospheric correction model, the residuals corresponding to each target base station are calculated, and the posterior variance of the ionospheric correction model is calculated based on each residual. Calculate the first distance between the external user and the main base station, and the average distance between each target base station and the main base station; Substituting the posterior variance, the first distance, and the average distance into the error propagation equation, the posterior variance is amplified based on the ratio of the first distance to the average distance to obtain the interpolation error.
[0016] Based on the calculated model residuals and posterior variance, this invention can objectively evaluate the model's fitting quality at the modeling points; by calculating the distance relationship between users and base stations, the geometric amplification effect of spatial extrapolation can be quantified; and by amplifying the posterior variance based on distance comparisons, the accuracy decay of the model at the extrapolation points can be scientifically predicted. Overall, based on the law of error propagation, by combining the model fitting error with spatial geometric relationships, the theoretical accuracy at the extrapolation points can be scientifically predicted, providing an objective and quantitative basis for weight allocation.
[0017] Furthermore, the positioning method also includes; If the maximum difference is greater than a preset threshold, the target ionospheric correction is set to zero so that the off-network user can locate the device based on the original observation data.
[0018] In this embodiment of the invention, when the maximum difference is greater than the threshold, the correction number is set to zero. This enables the correction to be abandoned proactively when the model results are inconsistent, thus avoiding the introduction of errors. It also allows users to locate based on the original observation data, provides a safe degradation scheme, ensures that the basic positioning function is not interrupted, and establishes a reliable safe positioning mechanism.
[0019] Another embodiment of the present invention provides a positioning system, including: a base station combination module, a correction calculation module, a determination module, and a positioning module; The base station combination module is used to determine multiple target base station sets from all the first base stations of the BeiDou ground-based augmentation system based on the initial location information of users outside the network. The users outside the network refer to users outside the preset service range of the BeiDou ground-based augmentation system. The correction calculation module is used to determine an ionospheric correction model for each target base station set based on the base station observation data of all target base stations, and to determine the initial ionospheric correction number between the external user and the target satellite based on the ionospheric correction model. The determination module is used to calculate the difference between each pair of all the initial ionospheric corrections, obtain the maximum difference, and compare the maximum difference with a preset threshold. The positioning module is configured to, if the maximum difference is less than or equal to a preset threshold, fuse the initial ionospheric corrections to obtain a target ionospheric correction, and send the target ionospheric correction to the off-network user so that the off-network user can perform positioning calculations based on the target ionospheric correction and the off-network user's original observation data to obtain target location information.
[0020] Another embodiment of the present invention provides a terminal device, including: a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, it implements the steps of the positioning method of the present invention.
[0021] Another embodiment of the present invention provides a computer-readable storage medium item, including: a stored computer program, which, when the computer program is running, controls the device where the computer-readable storage medium is located to perform the steps of the positioning method of the present invention. Attached Figure Description
[0022] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0023] Figure 1 This is a flowchart illustrating a positioning method provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a positioning system provided in an embodiment of the present invention. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.
[0026] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.
[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0028] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.
[0029] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).
[0030] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.
[0031] See Figure 1 To address the problem in existing technologies of how to enable CORS systems to provide reliable and high-precision ionospheric correction services to users outside the network, so that users outside the network can also achieve high-precision positioning based on CORS system base stations, an embodiment of the present invention provides a positioning method, comprising: Step S101: Based on the initial location information of users outside the network, determine multiple target base station sets from all the first base stations of the BeiDou ground-based augmentation system, wherein the users outside the network refer to users outside the preset service range of the BeiDou ground-based augmentation system.
[0032] In this embodiment, a location service request initiated by an external user is received. This request contains the user's initial location coordinates obtained through single-point positioning, with an accuracy typically on the order of meters. Based on this approximate location, multiple different subsets of base stations are selectively constructed from all available reference stations in the BeiDou ground-based augmentation system under its management. Each subset constitutes a target base station set. The core principle of selection is to ensure that the generated sets have sufficient spatial diversity, meaning that each set contains different base stations, and these sets are generally associated with the user's approximate location; for example, the base stations in the sets are roughly distributed in the area surrounding the user.
[0033] As an example of an embodiment of the present invention, determining multiple target base station sets from all first base stations of the BeiDou ground-based augmentation system based on the initial location information of the user outside the network specifically involves: determining a main base station and multiple second base stations from all first base stations based on the initial location information, wherein the main base station is the first base station closest to the user outside the network, and each second base station is a first base station whose distance from the main base station is within a preset range; and determining a first preset number of target base station sets based on the main base station and all second base stations.
[0034] In this embodiment, for all first base stations of the BeiDou CORS system, the geometric distance between each first base station and the user's initial location is calculated, and the base station with the closest distance is selected as the primary base station serving the user (denoted as station A). A spherical or circular screening area is defined in space with primary base station A as the center and a preset range as the radius. All base stations falling within this area are selected to obtain a second set of base stations. For example, from the surrounding base stations, 6 to 8 base stations with a distance of 20 to 50 kilometers from primary base station A are selected. These base stations constitute a candidate base station set. The preset range is determined based on a typical scale of ionospheric delay spatial correlation to ensure that the ionospheric state within this range has high similarity. From the second set of base stations, multiple different target base station sets are generated according to a first preset set size N and a second preset number of base stations in each set.
[0035] As an example of an embodiment of the present invention, the step of determining a first preset number of target base station sets based on the initial location information and based on the main base station and all the second base stations specifically involves: randomly selecting the first preset number of initial base station sets from all the second base stations, wherein the initial base station sets include a second preset number of second base stations; and combining the main base station with each of the initial base station sets to obtain each target base station set.
[0036] In this embodiment, multiple different subsets of base stations are randomly selected from the candidate base station set or selected according to specific rules. Each subset contains 2 or 3 candidate base stations, resulting in an initial base station set. Then, the main base station A is combined with each subset to form the final multiple target base station sets. The total number (K) of the target base station sets is usually not less than 4 sets to ensure sufficient samples for subsequent cross-validation. The structure of each set is {main base station A, base station 1 in the subset, base station 2 in the subset for calculating the first distance between the external user and the main base station} for calculating the first distance between the external user and the main base station (or adding a base station 3).
[0037] Step S102: For each set of target base stations, determine the ionospheric correction model based on the base station observation data of all target base stations, and determine the initial ionospheric correction number between the external user and the target satellite based on the ionospheric correction model.
[0038] In this embodiment, real-time observation data and precise coordinates of all base stations (e.g., stations A, B, and C) within each target base station set are acquired. The base station observation data includes B1 and B2 dual-frequency carrier phase and pseudorange observations of at least six BeiDou satellites (including GEO, IGSO, and MEO types). The carrier phase observations are processed, and their integer ambiguities are fixed using methods such as Lambda to obtain integer solutions. For target satellite i, the absolute value of the ionospheric delay from each base station (e.g., station A) within the set to the satellite is calculated using the ambiguity-fixed dual-frequency carrier phase observations. For each ionospheric delay value, methods such as linear interpolation are used to model and obtain the ionospheric correction model corresponding to the target base station set. Substituting the initial location information of the external user U into the above model, the initial ionospheric correction number of the external user U relative to satellite i predicted by the k-th ionospheric correction model is calculated. The calculation formula is as follows: ; Among them, a k and b k These are the model parameters of the k-th ionospheric correction model, obtained by linear interpolation based on the coordinates and ionospheric delay of each base station in the target base station set; X u Y u This refers to the initial location information (i.e., planar coordinates) of user u outside the network; X A Y A These are the planar coordinates of the main base station A.
[0039] As an example of an embodiment of the present invention, the base station observation data includes carrier phase values and pseudorange observation values. Specifically, for each set of target base stations, determining the ionospheric correction model based on the base station observation data of all target base stations involves: calculating the ionospheric delay of each target base station relative to the target satellite based on the carrier phase value and pseudorange observation value of each target base station; and processing each ionospheric delay using linear interpolation to obtain the ionospheric correction model corresponding to the set of target base stations.
[0040] In this embodiment, taking the A-station i satellite as an example, the ionospheric delay of the A-station i satellite with millimeter-level precision is calculated using the calculated satellite integer ambiguity and high-precision carrier phase observations. .
[0041] ; In the formula, , The frequencies of observations B1 and B2, , The wavelengths of observations B1 and B2 are... , The integer ambiguity of satellite B1 and B2 observations at station A. , These are the carrier observation values for frequency points B1 and B2 of satellite i at station A.
[0042] Taking a target base station set {A,B,C} and satellite i as an example, the planar coordinates of the three stations A, B, and C and the calculated ionospheric delay are compared. , and Using known points, an ionospheric correction model is constructed for each target base station set using linear interpolation. Parameters of the ionospheric correction model , The calculation formula is as follows: ; in, This represents the average distance between base stations in the area. This is the distance between station B and main station A. , This provides the north and east coordinates for station A.
[0043] Step S103: Calculate the difference between each pair of all the initial ionospheric corrections to obtain the maximum difference, and compare the maximum difference with a preset threshold.
[0044] In this embodiment, after S102, for the same target satellite i, based on the K initial ionospheric corrections (i.e., K different target base station set models) , ... Calculate the absolute difference between any two of the K corrections, and determine the largest difference from all calculated differences. The calculation formula is as follows: ; Maximum difference The results are compared with a preset consistency verification threshold T1, which is usually set to be less than or equal to 5 mm (≤5 mm). This threshold is the standard for judging whether the results of multiple models are consistent and reliable.
[0045] Step S104: If the maximum difference is less than or equal to a preset threshold, the initial ionospheric corrections are fused to obtain a target ionospheric correction. The target ionospheric correction is then sent to the off-network user so that the off-network user can perform positioning calculations based on the target ionospheric correction and the off-network user's original observation data to obtain the target location information.
[0046] In this embodiment, if If T1 ≤ T1, then the prediction results of all K ionospheric correction models for target satellite i are considered to be of good consistency and reliable, and the process proceeds to the fusion step. In the fusion step, for each ionospheric correction model, the interpolation error extrapolated to user u is calculated based on the error propagation law. The weight of each initial ionospheric correction is determined according to the interpolation error; for example, the smaller the interpolation error, the larger the weight. The weighted least squares method is used to fuse the K initial ionospheric corrections to calculate an optimal target ionospheric correction with the smallest variance. This fused target ionospheric correction is broadcast to users outside the network in real time. The user's receiver, locally, applies this correction to its own original observation data of satellite i to eliminate ionospheric delay errors. This process is repeated for all visible satellites. Finally, the user's receiver uses all corrected observations to calculate its own high-precision target position (centimeter-level).
[0047] As an example of an embodiment of the present invention, the step of fusing the initial ionospheric corrections to obtain the target ionospheric correction specifically involves: calculating the interpolation error of each ionospheric correction model based on the error propagation equation, and determining the weight corresponding to each initial ionospheric correction based on each interpolation error; and performing weighted fusion on the corresponding initial ionospheric corrections according to each weight to obtain the target ionospheric correction.
[0048] In this embodiment, based on the error propagation law, and combining the spatial distance between external users and surrounding base stations, the modeled posterior variance is used. Calculate the ionospheric interpolation error for each satellite for users outside the network. A weight matrix is designed based on the interpolation error information of each model, and the ionospheric corrections of each model are weighted and fused. The target ionospheric correction number of the target satellite is obtained from the user. The calculation formula is as follows: .
[0049] As an example of an embodiment of the present invention, the calculation of the interpolation error of each ionospheric correction model based on the error propagation equation specifically involves: for each target base station, calculating the residual corresponding to each target base station based on the ionospheric correction model, and calculating the posterior variance of the ionospheric correction model based on each residual; calculating the first distance between the external user and the main base station and the average distance between each target base station and the main base station; substituting the posterior variance, the first distance, and the average distance into the error propagation equation to amplify the posterior variance according to the ratio of the first distance to the average distance, thereby obtaining the interpolation error.
[0050] In this embodiment, the model parameter a is based on each ionospheric correction model k. k and b k Based on the ionospheric delay of base station B relative to target satellite i and the northward coordinates X of the target base station B B and the eastward coordinate Y B The residuals of each target base station were calculated. The calculation formula is as follows: ; The a priori variance is calculated based on the residuals of all ionospheric correction models. The calculation formula is as follows: ; Where j is the index of the target base station in the current set, which includes four base stations: A, B, C, and D. Based on the law of error propagation, and combined with the average distance between each target base station (B, C) and the main base station A, The first spatial distance between the external user u and the main base station and the posterior variance of the model The ionospheric interpolation error corresponding to each target satellite i for external user u is calculated. The calculation formula is as follows: .
[0051] As an example of an embodiment of the present invention, the positioning method further includes: if the maximum difference is greater than a preset threshold, setting the target ionospheric correction number to zero, so that the off-network user can perform positioning based on the original observation data.
[0052] In this embodiment, if If the first distance T1 between the external user and the main base station is calculated, it is determined that for the current target satellite, the ionospheric corrections provided by all K models have failed to reach a credible consensus, and the correction results are unreliable. For the satellite that is determined to be unreliable, no form of fusion calculation is performed, and the target ionospheric correction to be sent to the user is explicitly assigned a specific and meaningful value - zero (0). No ionospheric correction is applied, and the external user directly uses the original observation value containing the ionospheric delay to participate in the positioning solution, thus avoiding the introduction of erroneous correction values.
[0053] like Figure 2 As shown, based on the above-described method embodiments, an embodiment of the present invention provides a positioning system 200, including: a base station combination module 201, a correction calculation module 202, a determination module 203, and a positioning module 204; The base station combination module 201 is used to determine multiple target base station sets from all the first base stations of the BeiDou ground-based augmentation system based on the initial location information of users outside the network. The users outside the network refer to users outside the preset service range of the BeiDou ground-based augmentation system. The correction calculation module 202 is used to determine an ionospheric correction model for each set of target base stations based on the base station observation data of all target base stations, and to determine the initial ionospheric correction number between the external user and the target satellite based on the ionospheric correction model. The determination module 203 is used to calculate the difference between each pair of all the initial ionospheric corrections, obtain the maximum difference, and compare the maximum difference with a preset threshold. The positioning module 204 is used to fuse each of the initial ionospheric corrections to obtain a target ionospheric correction if the maximum difference is less than or equal to a preset threshold, and send the target ionospheric correction to the off-network user so that the off-network user can perform positioning calculation based on the target ionospheric correction and the off-network user's original observation data to obtain the target location information.
[0054] This invention determines multiple target base station sets based on the initial location information of users outside the network, expanding the scope of the correction service beyond a single user within the network and providing a foundation for subsequent multi-model analysis. For each set, an ionospheric correction model is determined and initial corrections are calculated. Ionospheric errors are evaluated from different spatial perspectives using multiple independent models, improving the comprehensiveness of the evaluation. A cross-validation mechanism is introduced, comparing the maximum difference between all corrections with a preset threshold, automatically determining the reliability of the model results and preventing unreliable corrections from affecting positioning. When the maximum difference is less than or equal to the threshold, the corrections are fused and sent to the user, ensuring that enhanced services are only provided when the results of multiple models are consistent, thus improving the reliability of the corrections. Users are then positioned based on the corrections and original observation data, extending the correction service from within the network to outside the network and achieving high-precision positioning for users outside the network.
[0055] Furthermore, the determination of multiple target base station sets from all first base stations of the BeiDou ground-based augmentation system based on the initial location information of users outside the network specifically involves: Among all the first base stations, a main base station and multiple second base stations are determined based on initial location information. The main base station is the first base station that is closest to the user outside the network, and each of the second base stations is a first base station whose distance from the main base station is within a preset range. Based on the main base station and all the second base stations, a first preset number of target base station sets is determined.
[0056] This invention, through its embodiments, determines the base station closest to the user as the primary base station, ensuring that the extrapolation starting point is closest to the user, minimizing the spatial extrapolation distance, and reducing extrapolation errors. It selects a second base station within a preset distance from the primary base station to ensure a reasonable spatial distribution of base stations participating in the modeling, guaranteeing ionospheric spatial correlation and improving model effectiveness. Based on the primary and second base stations, it determines a target set, forming a user-centric local modeling region, making the model more targeted. Overall, this lays a spatial foundation for constructing a high-quality ionospheric correction model and effectively controls the uncertainty of model extrapolation.
[0057] Further, the step of determining a first preset number of target base station sets based on the initial location information, based on the main base station and all the second base stations, specifically involves: From all the second base stations, a first preset number of initial base station sets are randomly selected, wherein the initial base station set includes a second preset number of second base stations; The main base station is combined with each of the initial base station sets to obtain each of the target base station sets.
[0058] In this embodiment of the invention, an initial set of base stations is randomly selected from the second base stations to ensure that multiple models have different spatial sampling points; each set contains a specific number of second base stations to control the complexity of each model and avoid overfitting or underfitting; the main base station is combined with each initial set to achieve the differential construction of multiple models while ensuring that all models contain the nearest reference point and maintain extrapolation consistency.
[0059] Furthermore, the base station observation data includes carrier phase values and pseudorange observation values. Specifically, for each set of target base stations, determining the ionospheric correction model based on the base station observation data of all target base stations involves: The ionospheric delay of each target base station relative to the target satellite is calculated based on the carrier phase value and the pseudorange observation value of each target base station. The ionospheric delay is processed by linear interpolation to obtain the ionospheric correction model corresponding to the target base station set.
[0060] This invention calculates the ionospheric delay of each base station to obtain the original observed values of ionospheric error, providing a data foundation for modeling; it uses linear interpolation to process the delay data, constructs a simple and effective spatial variation model, has high computational efficiency, and is suitable for real-time applications.
[0061] Furthermore, the process of fusing the initial ionospheric corrections to obtain the target ionospheric correction specifically involves: The interpolation error of each ionospheric correction model is calculated based on the error propagation equation, and the weights corresponding to each initial ionospheric correction number are determined based on each interpolation error. The initial ionospheric corrections are weighted and fused according to their respective weights to obtain the target ionospheric correction.
[0062] This invention calculates the interpolation error of each model to quantitatively evaluate the theoretical accuracy of each model at the extrapolation point; determines the weights based on the interpolation error to achieve intelligent weighting of high-precision models with high weights and low-precision models with low weights; and obtains the target correction number through weighted fusion, which can combine the advantages of multiple models to obtain a better result than any single model, achieving optimal fusion based on accuracy and significantly improving the accuracy and reliability of the final correction number.
[0063] Furthermore, the interpolation error of each ionospheric correction model calculated based on the error propagation equation is specifically as follows: For each target base station, based on the ionospheric correction model, the residuals corresponding to each target base station are calculated, and the posterior variance of the ionospheric correction model is calculated based on each residual. Calculate the first distance between the external user and the main base station, and the average distance between each target base station and the main base station; Substituting the posterior variance, the first distance, and the average distance into the error propagation equation, the posterior variance is amplified based on the ratio of the first distance to the average distance to obtain the interpolation error.
[0064] Based on the calculated model residuals and posterior variance, this invention can objectively evaluate the model's fitting quality at the modeling points; by calculating the distance relationship between users and base stations, the geometric amplification effect of spatial extrapolation can be quantified; and by amplifying the posterior variance based on distance comparisons, the accuracy decay of the model at the extrapolation points can be scientifically predicted. Overall, based on the law of error propagation, by combining the model fitting error with spatial geometric relationships, the theoretical accuracy at the extrapolation points can be scientifically predicted, providing an objective and quantitative basis for weight allocation.
[0065] Furthermore, the positioning method also includes; If the maximum difference is greater than a preset threshold, the target ionospheric correction is set to zero so that the off-network user can locate the device based on the original observation data.
[0066] In this embodiment of the invention, when the maximum difference is greater than the threshold, the correction number is set to zero. This enables the correction to be abandoned proactively when the model results are inconsistent, thus avoiding the introduction of errors. It also allows users to locate based on the original observation data, provides a safe degradation scheme, ensures that the basic positioning function is not interrupted, and establishes a reliable safe positioning mechanism.
[0067] It is understood that the above system item embodiments correspond to the method item embodiments of the present invention, and can implement the positioning method provided by any of the above method item embodiments of the present invention.
[0068] It should be noted that the system embodiments described above are merely illustrative, and some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the system embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.
[0069] For ease of description and brevity, the embodiments of the system items of the present invention include all the implementation methods in the above-described positioning method embodiments, and will not be repeated here.
[0070] Based on the above-described positioning method embodiments, another embodiment of the present invention provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it performs the following steps: Based on the initial location information of users outside the network, multiple target base station sets are determined from all the first base stations of the BeiDou ground-based augmentation system. The users outside the network refer to users outside the preset service range of the BeiDou ground-based augmentation system. For each set of target base stations, an ionospheric correction model is determined based on the base station observation data of all target base stations, and the initial ionospheric correction number between the external user and the target satellite is determined based on the ionospheric correction model. Calculate the pairwise differences between all the initial ionospheric corrections to obtain the maximum difference, and compare the maximum difference with a preset threshold. If the maximum difference is less than or equal to a preset threshold, the initial ionospheric corrections are fused to obtain a target ionospheric correction. The target ionospheric correction is then sent to the off-network user so that the off-network user can perform positioning calculations based on the target ionospheric correction and the off-network user's original observation data to obtain the target location information.
[0071] This invention determines multiple target base station sets based on the initial location information of users outside the network, expanding the scope of the correction service beyond a single user within the network and providing a foundation for subsequent multi-model analysis. For each set, an ionospheric correction model is determined and initial corrections are calculated. Ionospheric errors are evaluated from different spatial perspectives using multiple independent models, improving the comprehensiveness of the evaluation. A cross-validation mechanism is introduced, comparing the maximum difference between all corrections with a preset threshold, automatically determining the reliability of the model results and preventing unreliable corrections from affecting positioning. When the maximum difference is less than or equal to the threshold, the corrections are fused and sent to the user, ensuring that enhanced services are only provided when the results of multiple models are consistent, thus improving the reliability of the corrections. Users are then positioned based on the corrections and original observation data, extending the correction service from within the network to outside the network and achieving high-precision positioning for users outside the network.
[0072] Furthermore, the determination of multiple target base station sets from all first base stations of the BeiDou ground-based augmentation system based on the initial location information of users outside the network specifically involves: Among all the first base stations, a main base station and multiple second base stations are determined based on initial location information. The main base station is the first base station that is closest to the user outside the network, and each of the second base stations is a first base station whose distance from the main base station is within a preset range. Based on the main base station and all the second base stations, a first preset number of target base station sets is determined.
[0073] This invention, through its embodiments, determines the base station closest to the user as the primary base station, ensuring that the extrapolation starting point is closest to the user, minimizing the spatial extrapolation distance, and reducing extrapolation errors. It selects a second base station within a preset distance from the primary base station to ensure a reasonable spatial distribution of base stations participating in the modeling, guaranteeing ionospheric spatial correlation and improving model effectiveness. Based on the primary and second base stations, it determines a target set, forming a user-centric local modeling region, making the model more targeted. Overall, this lays a spatial foundation for constructing a high-quality ionospheric correction model and effectively controls the uncertainty of model extrapolation.
[0074] Further, the step of determining a first preset number of target base station sets based on the initial location information, based on the main base station and all the second base stations, specifically involves: From all the second base stations, a first preset number of initial base station sets are randomly selected, wherein the initial base station set includes a second preset number of second base stations; The main base station is combined with each of the initial base station sets to obtain each of the target base station sets.
[0075] In this embodiment of the invention, an initial set of base stations is randomly selected from the second base stations to ensure that multiple models have different spatial sampling points; each set contains a specific number of second base stations to control the complexity of each model and avoid overfitting or underfitting; the main base station is combined with each initial set to achieve the differential construction of multiple models while ensuring that all models contain the nearest reference point and maintain extrapolation consistency.
[0076] Furthermore, the base station observation data includes carrier phase values and pseudorange observation values. Specifically, for each set of target base stations, determining the ionospheric correction model based on the base station observation data of all target base stations involves: The ionospheric delay of each target base station relative to the target satellite is calculated based on the carrier phase value and the pseudorange observation value of each target base station. The ionospheric delay is processed by linear interpolation to obtain the ionospheric correction model corresponding to the target base station set.
[0077] This invention calculates the ionospheric delay of each base station to obtain the original observed values of ionospheric error, providing a data foundation for modeling; it uses linear interpolation to process the delay data, constructs a simple and effective spatial variation model, has high computational efficiency, and is suitable for real-time applications.
[0078] Furthermore, the process of fusing the initial ionospheric corrections to obtain the target ionospheric correction specifically involves: The interpolation error of each ionospheric correction model is calculated based on the error propagation equation, and the weights corresponding to each initial ionospheric correction number are determined based on each interpolation error. The initial ionospheric corrections are weighted and fused according to their respective weights to obtain the target ionospheric correction.
[0079] This invention calculates the interpolation error of each model to quantitatively evaluate the theoretical accuracy of each model at the extrapolation point; determines the weights based on the interpolation error to achieve intelligent weighting of high-precision models with high weights and low-precision models with low weights; and obtains the target correction number through weighted fusion, which can combine the advantages of multiple models to obtain a better result than any single model, achieving optimal fusion based on accuracy and significantly improving the accuracy and reliability of the final correction number.
[0080] Furthermore, the interpolation error of each ionospheric correction model calculated based on the error propagation equation is specifically as follows: For each target base station, based on the ionospheric correction model, the residuals corresponding to each target base station are calculated, and the posterior variance of the ionospheric correction model is calculated based on each residual. Calculate the first distance between the external user and the main base station, and the average distance between each target base station and the main base station; Substituting the posterior variance, the first distance, and the average distance into the error propagation equation, the posterior variance is amplified based on the ratio of the first distance to the average distance to obtain the interpolation error.
[0081] Based on the calculated model residuals and posterior variance, this invention can objectively evaluate the model's fitting quality at the modeling points; by calculating the distance relationship between users and base stations, the geometric amplification effect of spatial extrapolation can be quantified; and by amplifying the posterior variance based on distance comparisons, the accuracy decay of the model at the extrapolation points can be scientifically predicted. Overall, based on the law of error propagation, by combining the model fitting error with spatial geometric relationships, the theoretical accuracy at the extrapolation points can be scientifically predicted, providing an objective and quantitative basis for weight allocation.
[0082] Furthermore, the positioning method also includes; If the maximum difference is greater than a preset threshold, the target ionospheric correction is set to zero so that the off-network user can locate the device based on the original observation data.
[0083] In this embodiment of the invention, when the maximum difference is greater than the threshold, the correction number is set to zero. This enables the correction to be abandoned proactively when the model results are inconsistent, thus avoiding the introduction of errors. It also allows users to locate based on the original observation data, provides a safe degradation scheme, ensures that the basic positioning function is not interrupted, and establishes a reliable safe positioning mechanism.
[0084] For example, in this embodiment, the computer program can be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in the terminal device.
[0085] The terminal device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.
[0086] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting all parts of the terminal device via various interfaces and lines.
[0087] Based on the above-described method embodiments, another embodiment of the present invention provides a computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to perform the following steps: Based on the initial location information of users outside the network, multiple target base station sets are determined from all the first base stations of the BeiDou ground-based augmentation system. The users outside the network refer to users outside the preset service range of the BeiDou ground-based augmentation system. For each set of target base stations, an ionospheric correction model is determined based on the base station observation data of all target base stations, and the initial ionospheric correction number between the external user and the target satellite is determined based on the ionospheric correction model. Calculate the pairwise differences between all the initial ionospheric corrections to obtain the maximum difference, and compare the maximum difference with a preset threshold. If the maximum difference is less than or equal to a preset threshold, the initial ionospheric corrections are fused to obtain a target ionospheric correction. The target ionospheric correction is then sent to the off-network user so that the off-network user can perform positioning calculations based on the target ionospheric correction and the off-network user's original observation data to obtain the target location information.
[0088] This invention determines multiple target base station sets based on the initial location information of users outside the network, expanding the scope of the correction service beyond a single user within the network and providing a foundation for subsequent multi-model analysis. For each set, an ionospheric correction model is determined and initial corrections are calculated. Ionospheric errors are evaluated from different spatial perspectives using multiple independent models, improving the comprehensiveness of the evaluation. A cross-validation mechanism is introduced, comparing the maximum difference between all corrections with a preset threshold, automatically determining the reliability of the model results and preventing unreliable corrections from affecting positioning. When the maximum difference is less than or equal to the threshold, the corrections are fused and sent to the user, ensuring that enhanced services are only provided when the results of multiple models are consistent, thus improving the reliability of the corrections. Users are then positioned based on the corrections and original observation data, extending the correction service from within the network to outside the network and achieving high-precision positioning for users outside the network.
[0089] Furthermore, the determination of multiple target base station sets from all first base stations of the BeiDou ground-based augmentation system based on the initial location information of users outside the network specifically involves: Among all the first base stations, a main base station and multiple second base stations are determined based on initial location information. The main base station is the first base station that is closest to the user outside the network, and each of the second base stations is a first base station whose distance from the main base station is within a preset range. Based on the main base station and all the second base stations, a first preset number of target base station sets is determined.
[0090] This invention, through its embodiments, determines the base station closest to the user as the primary base station, ensuring that the extrapolation starting point is closest to the user, minimizing the spatial extrapolation distance, and reducing extrapolation errors. It selects a second base station within a preset distance from the primary base station to ensure a reasonable spatial distribution of base stations participating in the modeling, guaranteeing ionospheric spatial correlation and improving model effectiveness. Based on the primary and second base stations, it determines a target set, forming a user-centric local modeling region, making the model more targeted. Overall, this lays a spatial foundation for constructing a high-quality ionospheric correction model and effectively controls the uncertainty of model extrapolation.
[0091] Further, the step of determining a first preset number of target base station sets based on the initial location information, based on the main base station and all the second base stations, specifically involves: From all the second base stations, a first preset number of initial base station sets are randomly selected, wherein the initial base station set includes a second preset number of second base stations; The main base station is combined with each of the initial base station sets to obtain each of the target base station sets.
[0092] In this embodiment of the invention, an initial set of base stations is randomly selected from the second base stations to ensure that multiple models have different spatial sampling points; each set contains a specific number of second base stations to control the complexity of each model and avoid overfitting or underfitting; the main base station is combined with each initial set to achieve the differential construction of multiple models while ensuring that all models contain the nearest reference point and maintain extrapolation consistency.
[0093] Furthermore, the base station observation data includes carrier phase values and pseudorange observation values. Specifically, for each set of target base stations, determining the ionospheric correction model based on the base station observation data of all target base stations involves: The ionospheric delay of each target base station relative to the target satellite is calculated based on the carrier phase value and the pseudorange observation value of each target base station. The ionospheric delay is processed by linear interpolation to obtain the ionospheric correction model corresponding to the target base station set.
[0094] This invention calculates the ionospheric delay of each base station to obtain the original observed values of ionospheric error, providing a data foundation for modeling; it uses linear interpolation to process the delay data, constructs a simple and effective spatial variation model, has high computational efficiency, and is suitable for real-time applications.
[0095] Furthermore, the process of fusing the initial ionospheric corrections to obtain the target ionospheric correction specifically involves: The interpolation error of each ionospheric correction model is calculated based on the error propagation equation, and the weights corresponding to each initial ionospheric correction number are determined based on each interpolation error. The initial ionospheric corrections are weighted and fused according to their respective weights to obtain the target ionospheric correction.
[0096] This invention calculates the interpolation error of each model to quantitatively evaluate the theoretical accuracy of each model at the extrapolation point; determines the weights based on the interpolation error to achieve intelligent weighting of high-precision models with high weights and low-precision models with low weights; and obtains the target correction number through weighted fusion, which can combine the advantages of multiple models to obtain a better result than any single model, achieving optimal fusion based on accuracy and significantly improving the accuracy and reliability of the final correction number.
[0097] Furthermore, the interpolation error of each ionospheric correction model calculated based on the error propagation equation is specifically as follows: For each target base station, based on the ionospheric correction model, the residuals corresponding to each target base station are calculated, and the posterior variance of the ionospheric correction model is calculated based on each residual. Calculate the first distance between the external user and the main base station, and the average distance between each target base station and the main base station; Substituting the posterior variance, the first distance, and the average distance into the error propagation equation, the posterior variance is amplified based on the ratio of the first distance to the average distance to obtain the interpolation error.
[0098] Based on the calculated model residuals and posterior variance, this invention can objectively evaluate the model's fitting quality at the modeling points; by calculating the distance relationship between users and base stations, the geometric amplification effect of spatial extrapolation can be quantified; and by amplifying the posterior variance based on distance comparisons, the accuracy decay of the model at the extrapolation points can be scientifically predicted. Overall, based on the law of error propagation, by combining the model fitting error with spatial geometric relationships, the theoretical accuracy at the extrapolation points can be scientifically predicted, providing an objective and quantitative basis for weight allocation.
[0099] Furthermore, the positioning method also includes; If the maximum difference is greater than a preset threshold, the target ionospheric correction is set to zero so that the off-network user can locate the device based on the original observation data.
[0100] In this embodiment of the invention, when the maximum difference is greater than the threshold, the correction number is set to zero. This enables the correction to be abandoned proactively when the model results are inconsistent, thus avoiding the introduction of errors. It also allows users to locate based on the original observation data, provides a safe degradation scheme, ensures that the basic positioning function is not interrupted, and establishes a reliable safe positioning mechanism.
[0101] Based on the above-described method embodiments, this invention further provides a computer program / program product, which is stored in a storage medium and is executed by at least one processor in the following steps: Based on the initial location information of users outside the network, multiple target base station sets are determined from all the first base stations of the BeiDou ground-based augmentation system. The users outside the network refer to users outside the preset service range of the BeiDou ground-based augmentation system. For each set of target base stations, an ionospheric correction model is determined based on the base station observation data of all target base stations, and the initial ionospheric correction number between the external user and the target satellite is determined based on the ionospheric correction model. Calculate the pairwise differences between all the initial ionospheric corrections to obtain the maximum difference, and compare the maximum difference with a preset threshold. If the maximum difference is less than or equal to a preset threshold, the initial ionospheric corrections are fused to obtain a target ionospheric correction. The target ionospheric correction is then sent to the off-network user so that the off-network user can perform positioning calculations based on the target ionospheric correction and the off-network user's original observation data to obtain the target location information.
[0102] The modules / units integrated in the device / terminal equipment, if implemented as software functional units and sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.
[0103] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.
Claims
1. A positioning method, characterized in that, include: Based on the initial location information of users outside the network, multiple target base station sets are determined from all the first base stations of the BeiDou ground-based augmentation system. The users outside the network refer to users outside the preset service range of the BeiDou ground-based augmentation system. For each set of target base stations, an ionospheric correction model is determined based on the base station observation data of all target base stations, and the initial ionospheric correction number between the external user and the target satellite is determined based on the ionospheric correction model. Calculate the pairwise differences between all the initial ionospheric corrections to obtain the maximum difference, and compare the maximum difference with a preset threshold. If the maximum difference is less than or equal to a preset threshold, the initial ionospheric corrections are fused to obtain a target ionospheric correction. The target ionospheric correction is then sent to the off-network user so that the off-network user can perform positioning calculations based on the target ionospheric correction and the off-network user's original observation data to obtain the target location information.
2. The positioning method as described in claim 1, characterized in that, The process of determining multiple target base station sets from all first base stations of the BeiDou ground-based augmentation system based on the initial location information of users outside the network is specifically as follows: Among all the first base stations, a main base station and multiple second base stations are determined based on initial location information. The main base station is the first base station that is closest to the user outside the network, and each of the second base stations is a first base station whose distance from the main base station is within a preset range. Based on the main base station and all the second base stations, a first preset number of target base station sets is determined.
3. The positioning method as described in claim 2, characterized in that, The step of determining a first preset number of target base stations based on the initial location information, based on the main base station and all the second base stations, specifically involves: From all the second base stations, a first preset number of initial base station sets are randomly selected, wherein the initial base station set includes a second preset number of second base stations; The main base station is combined with each of the initial base station sets to obtain each of the target base station sets.
4. The positioning method as described in claim 1, characterized in that, in, The base station observation data includes carrier phase values and pseudorange observation values. Specifically, for each set of target base stations, an ionospheric correction model is determined based on the base station observation data of all target base stations. The ionospheric delay of each target base station relative to the target satellite is calculated based on the carrier phase value and the pseudorange observation value of each target base station. The ionospheric delay is processed by linear interpolation to obtain the ionospheric correction model corresponding to the target base station set.
5. The positioning method as described in claim 1, characterized in that, The process of fusing the initial ionospheric corrections to obtain the target ionospheric correction is specifically as follows: The interpolation error of each ionospheric correction model is calculated based on the error propagation equation, and the weights corresponding to each initial ionospheric correction number are determined based on each interpolation error. The initial ionospheric corrections are weighted and fused according to their respective weights to obtain the target ionospheric correction.
6. The positioning method as described in claim 5, characterized in that, The interpolation error of each ionospheric correction model, calculated based on the error propagation equation, is specifically as follows: For each target base station, based on the ionospheric correction model, the residuals corresponding to each target base station are calculated, and the posterior variance of the ionospheric correction model is calculated based on each residual. Calculate the first distance between the external user and the main base station, and the average distance between each target base station and the main base station; Substituting the posterior variance, the first distance, and the average distance into the error propagation equation, the posterior variance is amplified based on the ratio of the first distance to the average distance to obtain the interpolation error.
7. The positioning method as described in claim 1, characterized in that, The positioning method further includes; If the maximum difference is greater than a preset threshold, the target ionospheric correction is set to zero so that the off-network user can locate the device based on the original observation data.
8. A positioning system, characterized in that, include: Base station assembly module, correction calculation module, judgment module, and positioning module; The base station combination module is used to determine multiple target base station sets from all the first base stations of the BeiDou ground-based augmentation system based on the initial location information of users outside the network. The users outside the network refer to users outside the preset service range of the BeiDou ground-based augmentation system. The correction calculation module is used to determine an ionospheric correction model for each target base station set based on the base station observation data of all target base stations, and to determine the initial ionospheric correction number between the external user and the target satellite based on the ionospheric correction model. The determination module is used to calculate the difference between each pair of all the initial ionospheric corrections, obtain the maximum difference, and compare the maximum difference with a preset threshold. The positioning module is configured to, if the maximum difference is less than or equal to a preset threshold, fuse the initial ionospheric corrections to obtain a target ionospheric correction, and send the target ionospheric correction to the off-network user so that the off-network user can perform positioning calculations based on the target ionospheric correction and the off-network user's original observation data to obtain target location information.
9. A terminal device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, it implements the positioning method as described in any one of claims 1-7.
10. A computer-readable storage medium, characterized in that, include: A stored computer program, wherein, when the computer program is executed, it controls the device containing the computer-readable storage medium to perform the positioning method as described in any one of claims 1-7.