A joint positioning method and system for a dual-satellite-based real-time precise single-point positioning system

Abstract

This invention discloses a joint positioning method for a dual-satellite-based real-time precise point positioning system. This method synchronously receives and decodes real-time satellite orbits, clock errors, and code bias corrections from PPP-B2b and HAS. Through strategies such as orbit combination and clock error correction optimization and switching, real-time precise point positioning of the user terminal is achieved using the combined GPS, BDS-3, and Galileo systems. Regarding orbit corrections, a Helmert similarity transformation model is used to unify the reference values ​​of the two satellite-based PPP orbit products. A weight adjustment strategy combining a priori and a posteriori weighting is employed to generate a combined orbit product. Regarding clock error corrections, to address the issue of inconsistent time references between different satellite-based corrections, consistency detection of clock error types between consecutive epochs is performed, and the ambiguity parameters of the corresponding satellites are reset promptly.

Description

Technical Field

[0001] This invention belongs to the field of BeiDou / GNSS precision data processing and high-precision satellite navigation and positioning, specifically involving a joint positioning method based on the dual-satellite-based real-time precise point positioning (PPP) system of BeiDou PPP-B2b and Galileo HAS. Background Technology

[0002] Global Navigation Satellite Systems (GNSS) provide high-precision, high-frequency spatiotemporal information for human production and daily life, creating enormous socio-economic value. Precise Point Positioning (PPP), an important high-precision positioning technology, was initially proposed in the 1990s, but for a long time, its acquisition of precise orbit and clock bias products was delayed, limiting it to a post-processing model. With the development of internet communication technology, real-time PPP technology based on internet communication links has become possible. Currently, the International GNSS Service (IGS) has been providing real-time satellite orbit and clock bias products, broadcasting them to users via the internet. While this real-time PPP solution offers advantages such as low cost and global coverage, it relies on terrestrial communication network services and remains unusable in areas with weak internet infrastructure, such as deserts and oceans. To address this issue, some commercial companies are currently using geosynchronous orbit (GEO) satellites to broadcast high-precision real-time correction products to users; however, these commercial solutions are relatively expensive.

[0003] In recent years, major global navigation satellite systems have successively launched their own high-precision PPP services, such as the BeiDou-3 system (BDS-3) and the Galileo system. Currently, BDS-3 and Galileo systems began providing publicly available, free real-time PPP services in 2020 and 2023, respectively, namely the PPP-B2b service based on B2b signals and the Galileo High Accuracy Service (HAS) based on E6-B signals. They utilize navigation satellite signals as correction data broadcasting channels, unaffected by network fluctuations and interruptions. However, compared to real-time services (RTS) transmitted via the internet, the accuracy of satellite-based real-time orbits and clock biases is relatively poor. Furthermore, the number of satellite systems and satellites supported by a single augmentation system is limited, making it difficult to further improve positioning accuracy. Moreover, when applying a single satellite-based PPP correction product, it is susceptible to server-side failures, satellite broadcasting links, and signal interference from the user end, leading to interruptions, errors, and other anomalies in the correction data product, thus increasing the risk of disruption to real-time PPP positioning continuity. Therefore, integrating multiple satellite-based PPP precision products and optimizing and fusing multi-satellite orbit and clock difference products to achieve joint precision positioning is crucial for improving positioning accuracy and reliability. Summary of the Invention

[0004] To address the shortcomings in accuracy, reliability, and continuity of current positioning methods using single satellite-based PPP corrections, this invention designs a strategy for processing orbit and clock error corrections in joint positioning. It proposes a method for GPS+BDS-3+Galileo three-system satellite-based PPP positioning by combining PPP-B2b and GalileoHAS, effectively improving the performance of satellite-based PPP user terminal positioning services.

[0005] According to one aspect of the present invention, a joint positioning method for a dual-satellite-based real-time precise single-point positioning system is provided, comprising:

[0006] Step 1: Acquire and decode the synchronously received PPP-B2b and Galileo HAS navigation augmentation message information, match the satellite-based augmentation orbit and clock correction with the corresponding broadcast ephemeris orbit and clock products, and recover the complete and precise satellite orbit and satellite clock products of all available satellites in the current epoch.

[0007] Step 2: Construct a common satellite subset of the real-time correction products provided by BeiDou PPP-B2b and Galileo HAS in the current epoch, and preprocess the orbit products of the common satellite subset to remove anomalies, so as to obtain "clean" orbit products of the common satellite subsets of the two satellite-based PPP systems.

[0008] Step 3: Generate a combined orbit of public satellites based on the public satellite subset, and calculate the coordinate reference transformation parameters between the combined orbit product of the public satellite subset and the satellite-based PPP orbit product;

[0009] Step 4: Using the coordinate reference transformation parameters calculated in Step 3, transfer all non-public satellite orbit products to the same coordinate reference frame as the combined orbit products of public satellites.

[0010] Step 5: Correct the differences between the combined orbit and the B2b / HAS orbit to their respective satellite clock products;

[0011] Step 6: When the clock correction number used for positioning in the dual-satellite system changes, perform a clock error type consistency check between previous and subsequent epochs on the satellite-based clock error, and reset the ambiguity of satellites that fail the check.

[0012] Step 7: Using the corrected precision orbit and clock error corrections provided in Steps 5 and 6, achieve precise positioning of the joint dual-satellite-based PPP system.

[0013] As a further technical solution, step 1 also includes:

[0014] Simultaneously receive real-time correction data from both PPP-B2b and HAS satellite-based PPP systems, including satellite orbit correction data, clock error correction data, and code offset correction data;

[0015] After receiving the broadcast enhancement message, the SSR correction numbers of different types are obtained according to the format.

[0016] After decoding, the correction data product is matched with the corresponding broadcast ephemeris by the data version number of the correction data to restore the real-time precise satellite orbits and satellite clock biases of all available satellites in the current epoch.

[0017] As a further technical solution, step 2 also includes:

[0018] Anomalies in orbits are detected by cross-verifying two products. When the difference between the two satellite-based orbits in any direction exceeds a threshold, the satellite's PPP-B2b orbit or Galileo HAS orbit is considered to be abnormal.

[0019] As a further technical solution, step 3, which calculates the combined orbit of the public satellites and the coordinate reference transformation parameters between the combined orbit and the satellite-based PPP orbit product using the iterative weighted least squares method, also includes:

[0020] The Helmert similarity transformation model is used to unify the benchmark between different satellite orbit products. The parameters to be estimated at each epoch are the combined orbit of each satellite and the seven transformation parameters corresponding to each orbit product. The weight of the combined orbit is determined by combining the prior weighting of product accuracy assessment and the posterior weighting based on observations.

[0021] As a further technical solution, step 4 also includes:

[0022] Using the coordinate reference transformation parameters calculated in step 3, all non-public satellite orbit products are transformed to the same coordinate reference frame as the combined orbit products of public satellites according to the Helmert similarity transformation model. The Helmert parameter transformation method achieves high-precision coordinate system transformation by estimating one scale parameter, three translation parameters, and three rotation parameters.

[0023] As a further technical solution, step 5 also includes:

[0024] The formula for calculating orbit clock consistency correction for satellite-based clock bias is as follows:

[0025]

[0026] In the formula, The track clock consistency correction for product a (real-time clock difference) is expressed in seconds. and These are the satellite coordinate vectors for a specific satellite-based orbit and a combined orbit, respectively. Let represent the unit vector corresponding to the star-based orbit, and c be the speed of light in a vacuum.

[0027] As a further technical solution, step 6, which involves detecting the consistency of clock bias types between consecutive epochs for satellite-based clock biases, also includes:

[0028] Mark the type of clock correction used by each GPS satellite in the current epoch i;

[0029] For each satellite in the subset, check if the label of the current epoch is the same as the label of the previous epoch;

[0030] If they are the same, it means that the clock correction type used by the satellite at different epochs is consistent; if they are different, it means that the clock correction type used by the satellite at different epochs is inconsistent, and the ambiguity parameters of the satellite should be reset.

[0031] According to one aspect of the present invention, a dual-satellite-based real-time precise point positioning system is provided, comprising:

[0032] The first main module is used to acquire and decode the synchronously received PPP-B2b and Galileo HAS navigation enhancement message information, match the satellite-based augmentation orbit and clock correction with the corresponding broadcast ephemeris orbit and clock products, and recover the complete and precise satellite orbit and satellite clock products of all available satellites in the current epoch.

[0033] The second main module is used to construct a common satellite subset of the real-time correction products provided by Beidou PPP-B2b and Galileo HAS in the current epoch, and to preprocess the orbit products of the common satellite subset to remove anomalies, so as to obtain "clean" orbit products of the common satellite subsets of the two satellite-based PPP systems.

[0034] The third main module is used to generate a combined orbit of public satellites based on a subset of public satellites, and to calculate the coordinate reference transformation parameters between the combined orbit product of the public satellite subset and the satellite-based PPP orbit product.

[0035] The fourth main module is used to convert the orbital products of all non-public satellites to the same coordinate reference frame as the combined orbital products of public satellites using the calculated coordinate reference transformation parameters.

[0036] The fifth main module is used to correct the differences between the combined orbit and the B2b / HAS orbit to their respective satellite clock products;

[0037] The sixth main module is used to perform a clock error type consistency check between previous and subsequent epochs on the satellite-based clock error when the clock error correction number used for positioning in the dual-satellite system changes, and to reset the ambiguity of satellites that fail the check.

[0038] The seventh main module is used to achieve precise positioning of the joint dual-satellite-based PPP system using the provided corrected precision orbit and clock error corrections.

[0039] According to one aspect of the present invention, an electronic device is provided, including a memory and a processor, the memory storing program instructions that are executed by the processor, the processor calling the program instructions to execute the aforementioned dual-satellite-based real-time precise single-point positioning system joint positioning method.

[0040] According to one aspect of the present invention, a non-transitory computer-readable storage medium is provided, the non-transitory computer-readable storage medium storing computer instructions that cause the computer to execute the aforementioned dual-satellite-based real-time precise single-point positioning system joint positioning method.

[0041] Traditional satellite-based PPP systems are susceptible to server-side failures, signal obstruction, or interference during practical applications, leading to interruptions and errors in the received satellite-based correction data, thus affecting service performance. Compared with existing technologies, the advantages of this invention are:

[0042] This invention can use the orbital corrections of two satellite-based PPPs on a subset of common satellites to cross-check each other, promptly eliminate satellites with abnormal orbits, and make full use of as many available satellites as possible in the solution, thereby improving the availability of GPS single satellites and increasing positioning accuracy and convergence speed. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 A schematic diagram of the flowchart of the joint positioning method based on BeiDou PPP-B2b and Galileo HAS dual-satellite-based PPP system provided as an example of the present invention.

[0045] Figure 2 The following is a time series diagram of real-time orbital error of GPS satellites PPP-B2b and Galileo HAS, provided as an example of the present invention.

[0046] Figure 3 This diagram illustrates the number of available satellites and PDOP values ​​of the MIZU station in single BeiDou PPP-B2b, single Galileo HAS, and dual-satellite-based PPP modes, as provided for examples of this invention.

[0047] Figure 4 A schematic diagram of dynamic positioning error of MIZU station in single BeiDou PPP-B2b, single Galileo HAS and dual satellite-based PPP modes provided for the example of the present invention. Detailed Implementation

[0048] This invention provides a joint positioning method based on the BeiDou PPP-B2b and Galileo HAS dual-satellite-based PPP systems. This method synchronously receives and processes real-time orbit and clock correction data from PPP-B2b and Galileo HAS, and achieves joint real-time precise point positioning using strategies such as orbit combination and clock correction switching.

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined to form new technical solutions. Such combinations are not bound by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0050] like Figure 1 As shown, this invention provides a joint positioning method based on BeiDou PPP-B2b and Galileo HAS dual-satellite-based PPP systems, comprising the following steps:

[0051] Step 1: Acquire and decode the synchronously received PPP-B2b and Galileo HAS navigation augmentation message information, match the satellite-based augmentation orbit and clock correction with the corresponding broadcast ephemeris orbit and clock products, and recover the complete and precise satellite orbits and satellite clock products of all available satellites at the current epoch.

[0052] Step 2: Construct a common satellite subset of the real-time correction products provided by BeiDou PPP-B2b and Galileo HAS in the current epoch, and preprocess the orbit products of the common satellite subset to remove anomalies such as gross errors and jump values, so as to obtain "clean" orbit products of the common satellite subsets of the two satellite-based PPP systems.

[0053] Step 3: Generate a combined orbit of public satellites based on the public satellite subset, and calculate the coordinate reference transformation parameters between the combined orbit product of the public satellite subset and the satellite-based PPP orbit product.

[0054] Step 4: Using the coordinate reference transformation parameters calculated in Step 3, transfer the orbital products of all non-public satellites to the same coordinate reference frame as the combined orbital products of public satellites.

[0055] Step 5: Since there is a strong correlation between satellite clock bias and satellite orbit, in order to maintain consistency and self-consistency, it is necessary to perform orbit clock consistency correction on satellite clock bias, that is, to correct the difference between the combined orbit and the B2b / HAS orbit to their respective satellite clock bias products.

[0056] Step 6: When the clock correction used for positioning by the dual-satellite system is switched (i.e., using GPS clock corrections provided by BeiDou PPP-B2b or Galileo HAS), there is a significant difference in the time reference. It is necessary to perform a consistency check on the clock correction type between consecutive epochs of the satellite-based system and reset the ambiguity of satellites that fail the check.

[0057] Step 7: Using the corrected precision orbit and clock error corrections provided in Steps 5 and 6, precise positioning of the joint dual-satellite-based PPP system can be achieved.

[0058] Furthermore, step 1 requires simultaneous reception of real-time correction data from both PPP-B2b and HAS satellite-based PPP systems, including satellite orbit corrections, clock bias corrections, and code offset corrections. After receiving the broadcast enhanced message, the user can decode it according to the format to obtain different types of SSR correction data. After decoding, the correction data product is matched with the corresponding broadcast ephemeris using the correction data's issue of data (IOD) to recover the real-time precise satellite orbits and clock biases of all available satellites in the current epoch.

[0059] Furthermore, in step 2, a common satellite subset of the real-time correction products provided by BeiDou PPP-B2b and Galileo HAS at the current epoch is constructed, and anomaly data preprocessing is performed on the orbits of the common subset. This invention uses a method of mutual verification between the two products to detect orbital anomalies. When the difference between the two satellite-based orbits in any direction exceeds a threshold Θ (set to an empirical value of 1m in this invention), it is considered that the PPP-B2b orbit or Galileo HAS orbit of that satellite is anomaly.

[0060] Furthermore, in step 3, based on the public satellite subset of PPP-B2b and Galileo HAS products, the coordinate reference transformation parameters between the combined orbit product of the public satellite subset and the satellite-based PPP orbit product are calculated. Specifically, this includes calculating the combined orbit of the public satellites and the coordinate reference transformation parameters between the combined orbit and the satellite-based PPP orbit product using an iterative weighted least squares method. First, the reference between different satellite orbit products is unified using the Helmert similarity transformation model, i.e., a one-step method can directly obtain the combined orbit and its Helmert transformation parameters. The mathematical model is as follows:

[0061]

[0062] In the formula, s represents a satellite. and Indicates the combined orbital coordinates of the satellites. These represent the satellite orbits corresponding to product type 'a', where 'a' represents either the Galileo HAS or PPP-B2b real-time product. The parameters to be estimated at each epoch are the combined orbits of each satellite and the seven transformation parameters corresponding to each orbit product.

[0063] Based on the above mathematical model, the linearized error equation for the i-th epoch is:

[0064]

[0065] in, Represents the design matrix, l a,i This represents the difference between the actual observed value and the estimated value. The specific expression for the observed residual vector can be written as:

[0066]

[0067] In the formula, M a , and These represent the scale, rotation, and translation parameters corresponding to orbital product a (where a is either the PPP-B2b or Galileo HAS product). The initial values ​​for the combined orbit are set to the average values ​​of the PPP-B2b and Galileo HAS orbits, and the initial values ​​for the Helmert transform parameters are calculated based on the transform model. The coefficient matrix of the combined orbitals. and E are the coefficient matrices for the scale and rotation parameters, respectively. i Let be a 3×3 identity matrix, and be the coefficient matrix of the translation parameters.

[0068] From the error equation Based on the characteristics, the PPP-B2b or Galileo HAS satellite orbits have the same coefficient matrix as the Helmert transformation parameters of the combined orbits. Therefore, a baseline constraint needs to be added to the model to separate the transformation parameters.

[0069]

[0070] To address the weight determination problem in the orbital combination process, this invention employs a combination of prior weighting for product accuracy assessment and posterior weighting based on observations. The specific method is as follows:

[0071] (1) Prior weights: The external conformity accuracy of the orbit products can be obtained by evaluating the historical orbit data of Beidou PPP-B2b and Galileo HAS. The weights of the two orbit products in the combined algorithm are determined according to different accuracy levels. That is, the prior weights are taken as the reciprocal of the ratio of the average error RMS of HAS orbit and PPP-B2b orbit.

[0072] (2) Posterior weights: In each iteration, the weights are dynamically adjusted based on the residual value of each satellite. This invention uses the following IGGIII equivalent weight function for adjustment:

[0073]

[0074] In the formula, p i and Let v' be the initial weight and the adjusted weight for the i-th observation. i To standardize the residuals, k0 and k1 are the critical values ​​of the deweighting region and the rejection region, respectively, and are taken as empirical values ​​of 3 and 6.

[0075] Furthermore, step 4 uses the transformation parameters obtained in step 3 to transform the orbits of all non-public satellites to the same reference frame as the combined orbits of the public satellite subset, based on the Helmert similarity transformation model. The Helmert seven-parameter transformation method achieves high-precision coordinate system transformation by estimating one scale parameter, three translation parameters, and three rotation parameters. The Helmert transformation model between different satellite-based PPP real-time satellite orbit products is as follows:

[0076]

[0077] In the formula, and These represent the satellite coordinates obtained from the reference product. and M and R represent the satellite coordinates obtained from the satellite-based PPP product to be converted, where s represents the satellite and i represents the epoch. k T k (k = x, y, z) represent the scale parameter, rotation parameter, and translation parameter of the product to be converted, respectively.

[0078] Furthermore, in step 5, after completing the orbit combination, the differences between the combined orbit and the PPP-B2b and Galileo HAS satellite-based orbits are corrected onto their respective satellite-based clock bias products to ensure consistency between the satellite-based orbits and clock bias products. The formula for calculating this consistency correction is as follows:

[0079]

[0080] In the formula, The clock consistency correction for real-time clock difference product a is expressed in seconds. and These are the satellite coordinate vectors for a specific satellite-based orbit (provided by PPP-B2b or Galileo HAS) and a combined orbit, respectively. Let represent the unit vector corresponding to the star-based orbit, and c be the speed of light in vacuum. Then the corrected clock error can be expressed as:

[0081]

[0082] Furthermore, in step 6, the consistency of clock error types between consecutive epochs is checked for the satellite clock errors. First, the clock error correction type used by each GPS satellite in the current epoch i is marked. Then, for each satellite in the subset, it is checked whether the marking in the current epoch is the same as the marking in the previous epoch. If they are the same, it means that the clock error correction type used by the satellite in consecutive epochs is consistent, and no special processing is required; if they are different, it means that the clock error correction type used by the satellite in consecutive epochs is inconsistent, and the ambiguity parameters of the satellite are reset.

[0083] Figure 2 Error sequences for the GPS satellite PPP-B2b real-time orbits and Galileo HAS real-time orbits are presented. The left column of the figure represents the PPP-B2b real-time orbit, and the right column represents the Galileo HAS real-time orbit. The three rows from top to bottom represent radial error, tangential error, and normal error, respectively. As shown in the figure, the radial accuracy of the HAS satellite orbit is similar to that of the PPP-B2b orbit, both within 0.2m, while the tangential and normal accuracy are significantly better than those of the PPP-B2b orbit, with smaller errors and more stable fluctuations. Therefore, based on the evaluation results of the accuracy of the two orbit products, a higher prior weight should be given to the HAS product when combining them to ensure accuracy. The prior weight is taken as the reciprocal of the ratio of the average RMS error of the HAS orbit to that of the PPP B2b orbit.

[0084] Figure 3 The figures show the number of available satellites and PDOP changes for the MIZU station in DOY 020 2024 using single BeiDou PPP-B2b, single Galileo HAS, and dual-satellite PPP modes. The method described in this invention is labeled as the "Comb" mode. As can be seen from the figures, the method of this invention can utilize as many GPS satellites as possible, with an average of 22.4 available satellites participating in the calculation, significantly higher than the 14.6 and 13.6 satellites in the single BeiDou PPP-B2b and single Galileo HAS modes, respectively. Simultaneously, the PDOP value sequence of the method of this invention is also significantly lower than that using any single satellite-based PPP system.

[0085] Figure 4The dynamic PPP positioning errors of the MIZU station during DOY 020 2024 were presented using single BeiDou PPP-B2b, single Galileo HAS, and dual-satellite-based PPP modes. The method described in this invention is labeled as the "Comb" mode. As shown in the figure, the positioning error sequence of the method described in this invention exhibits significantly reduced fluctuations, demonstrating higher positioning accuracy and stability. While the positioning results of single BeiDou PPP-B2b and single Galileo HAS showed some jumps or fluctuations in both the E and U directions, the method described in this invention still maintained relatively stable positioning results, with the maximum error fluctuation in the U direction not exceeding 0.3m.

[0086] The implementation of the various embodiments of the present invention is based on programmed processing by a device with processor functionality. Therefore, in practical engineering, the technical solutions and functions of the various embodiments of the present invention are encapsulated into various modules. Based on this reality, and building upon the above embodiments, the embodiments of the present invention provide a dual-satellite-based real-time precise single-point positioning system joint positioning system, which is used to execute a dual-satellite-based real-time precise single-point positioning system joint positioning method from the above method embodiments.

[0087] The system includes: a first main module, used to acquire and decode synchronously received PPP-B2b and Galileo HAS navigation augmentation message information, time-match the satellite-based augmentation orbits and clock corrections with the corresponding broadcast ephemeris orbits and clock bias products, and recover the complete and precise satellite orbits and satellite clock bias products of all available satellites in the current epoch; and a second main module, used to construct the BeiDou PPP-B2b and Galileo HAS navigation augmentation message information for the current epoch. The system uses a subset of public satellites provided by HAS for real-time correction products, preprocesses the orbit products of this subset to remove anomalies, and obtains "clean" orbit products for the two types of satellite-based PPP system public satellite subsets. The third main module generates combined orbits for the public satellites based on the subsets and calculates the coordinate reference transformation parameters between the combined orbit products and the satellite-based PPP orbit products. The fourth main module uses the calculated coordinate reference transformation parameters to convert all non-public satellite orbit products to the same coordinate reference frame as the combined orbit products of the public satellites. The fifth main module corrects the differences between the combined orbits and the B2b / HAS orbits onto their respective satellite clock bias products. The sixth main module performs clock bias type consistency checks on the satellite clock bias between epochs when the clock bias corrections used in dual-satellite system positioning change, and resets the ambiguities of satellites that fail the check. The seventh main module uses the provided corrected precise orbits and clock bias corrections to achieve precise positioning using the joint dual-satellite PPP system.

[0088] This invention provides a dual-satellite-based real-time precise single-point positioning system, addressing the shortcomings in accuracy, reliability, and continuity of current positioning systems using single-satellite-based PPP corrections. It employs several modules and designs a strategy for processing orbit and clock corrections in joint positioning. By combining PPP-B2b and Galileo HAS, it performs GPS+BDS-3+Galileo three-system satellite-based PPP positioning, effectively improving the performance of satellite-based PPP user-end positioning services.

[0089] It should be noted that the system embodiments provided by the present invention are used not only to implement the methods in the above method embodiments, but also to implement the methods in other method embodiments provided by the present invention. The only difference is that corresponding functional modules are set. The principle is basically the same as that of the above system embodiments provided by the present invention. As long as those skilled in the art can improve the modules in the above system embodiments by referring to the specific technical solutions in other method embodiments and combining technical features to obtain corresponding technical means and technical solutions composed of these technical means, on the basis of the above system embodiments, and on the premise of ensuring the practicality of the technical solutions, they can obtain corresponding system-like embodiments for implementing the methods in other method-like embodiments.

[0090] Based on the same inventive concept as the foregoing embodiments, this embodiment of the invention also provides an electronic device, including a memory and a processor. The memory stores program instructions that are executed by the processor, and the processor calls the program instructions to execute the aforementioned dual-satellite-based real-time precise single-point positioning system joint positioning method.

[0091] Based on the same inventive concept as the foregoing embodiments, this embodiment of the invention also provides a non-transitory computer-readable storage medium storing computer instructions that cause the computer to execute the aforementioned joint positioning method for a dual-satellite-based real-time precise single-point positioning system, including:

[0092] Step 1: Acquire and decode the synchronously received PPP-B2b and Galileo HAS navigation augmentation message information, match the satellite-based augmentation orbit and clock correction with the corresponding broadcast ephemeris orbit and clock products, and recover the complete and precise satellite orbit and satellite clock products of all available satellites in the current epoch.

[0093] Step 2: Construct a common satellite subset of the real-time correction products provided by BeiDou PPP-B2b and Galileo HAS in the current epoch, and preprocess the orbit products of the common satellite subset to remove anomalies, so as to obtain "clean" orbit products of the common satellite subsets of the two satellite-based PPP systems.

[0094] Step 3: Generate a combined orbit of public satellites based on the public satellite subset, and calculate the coordinate reference transformation parameters between the combined orbit product of the public satellite subset and the satellite-based PPP orbit product;

[0095] Step 4: Using the coordinate reference transformation parameters calculated in Step 3, transfer all non-public satellite orbit products to the same coordinate reference frame as the combined orbit products of public satellites.

[0096] Step 5: Correct the differences between the combined orbit and the B2b / HAS orbit to their respective satellite clock products;

[0097] Step 6: When the clock correction number used for positioning in the dual-satellite system changes, perform a clock error type consistency check between previous and subsequent epochs on the satellite-based clock error, and reset the ambiguity of satellites that fail the check.

[0098] Step 7: Using the corrected precision orbit and clock error corrections provided in Steps 5 and 6, achieve precise positioning of the joint dual-satellite-based PPP system.

[0099] In summary, this invention discloses a joint precise positioning method for a dual-satellite-based PPP system based on BeiDou-3 PPP-B2b service and Galileo HAS service. This method synchronously receives and decodes real-time satellite orbits, clock biases, and code offset corrections from PPP-B2b and HAS. Through strategies such as orbit combination and clock bias correction optimization and switching, real-time precise single-point positioning of the user terminal using the combined GPS+BDS-3+Galileo three systems is achieved. Regarding orbit corrections, the Helmert similarity transformation model unifies the reference of the two satellite-based PPP orbit products, and a weight adjustment strategy combining a priori and a posteriori weighting is adopted to generate a combined orbit product. Regarding clock bias corrections, to address the issue of inconsistent time references between different satellite-based corrections, consistency detection of clock bias types between consecutive epochs is performed, and the ambiguity parameters of the corresponding satellites are reset in a timely manner. This multi-satellite-based PPP joint positioning method addresses the impact of server-side failures and user-side signal obstruction on positioning accuracy and continuity in practical applications of the BeiDou and Galileo satellite-based PPP systems. It effectively mitigates error jumps caused by correction switching and achieves real-time satellite-based PPP user-side services with faster convergence speed and better positioning accuracy and continuity.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A joint positioning method for a dual-satellite-based real-time precise single-point positioning system, characterized in that, include: Step 1: Acquire and decode the synchronously received PPP-B2b and Galileo HAS navigation augmentation message information, match the satellite-based augmentation orbit and clock correction with the corresponding broadcast ephemeris orbit and clock products, and recover the complete and precise satellite orbit and satellite clock products of all available satellites in the current epoch. Step 2: Construct a common satellite subset of the real-time correction products provided by BeiDou PPP-B2b and Galileo HAS in the current epoch, and preprocess the orbit products of the common satellite subset to remove anomalies, so as to obtain "clean" orbit products of the common satellite subsets of the two satellite-based PPP systems. Step 3: Generate a combined orbit of public satellites based on the public satellite subset, and calculate the coordinate reference transformation parameters between the combined orbit product of the public satellite subset and the satellite-based PPP orbit product; Step 4: Using the coordinate reference transformation parameters calculated in Step 3, transfer all non-public satellite orbit products to the same coordinate reference frame as the combined orbit products of public satellites. Step 5: Correct the differences between the combined orbit and the B2b / HAS orbit to their respective satellite clock products; Step 6: When the clock correction number used for positioning in the dual-satellite system changes, perform a clock error type consistency check between previous and subsequent epochs on the satellite-based clock error, and reset the ambiguity of satellites that fail the check. Step 7: Using the corrected precision orbit and clock error corrections provided in Steps 5 and 6, achieve precise positioning of the joint dual-satellite-based PPP system.

2. The joint positioning method of a dual-satellite-based real-time precise single-point positioning system according to claim 1, characterized in that, Step 1 further includes: Simultaneously receive real-time correction data from both PPP-B2b and HAS satellite-based PPP systems, including satellite orbit correction data, clock error correction data, and code offset correction data; After receiving the broadcast enhancement message, the SSR correction numbers of different types are obtained according to the format. After decoding, the correction data product is matched with the corresponding broadcast ephemeris by the data version number of the correction data to restore the real-time precise satellite orbits and satellite clock biases of all available satellites in the current epoch.

3. The joint positioning method of a dual-satellite-based real-time precise single-point positioning system according to claim 1, characterized in that, Step 2 also includes: Anomalies in orbits are detected by cross-verifying two products. When the difference between the two satellite-based orbits in any direction exceeds a threshold, the satellite's PPP-B2b orbit or Galileo HAS orbit is considered to be abnormal.

4. The joint positioning method of a dual-satellite-based real-time precise single-point positioning system according to claim 1, characterized in that, Step 3, which calculates the combined orbit of the public satellites and the coordinate reference transformation parameters between the combined orbit and the satellite-based PPP orbit product using the iterative weighted least squares method, also includes: The Helmert similarity transformation model is used to unify the benchmark between different satellite orbit products. The parameters to be estimated at each epoch are the combined orbit of each satellite and the seven transformation parameters corresponding to each orbit product. The weight of the combined orbit is determined by combining the prior weighting of product accuracy assessment and the posterior weighting based on observations.

5. The joint positioning method of a dual-satellite-based real-time precise single-point positioning system according to claim 1, characterized in that, Step 4 also includes: Using the coordinate reference transformation parameters calculated in step 3, all non-public satellite orbit products are transformed to the same coordinate reference frame as the combined orbit products of public satellites according to the Helmert similarity transformation model. The Helmert parameter transformation method achieves high-precision coordinate system transformation by estimating one scale parameter, three translation parameters, and three rotation parameters.

6. The joint positioning method of a dual-satellite-based real-time precise single-point positioning system according to claim 1, characterized in that, Step 5 further includes: The formula for calculating orbit clock consistency correction for satellite-based clock bias is as follows: In the formula, The track clock consistency correction for product a (real-time clock difference) is expressed in seconds. and These are the satellite coordinate vectors for a specific satellite-based orbit and a combined orbit, respectively. Let represent the unit vector corresponding to the star-based orbit, and c be the speed of light in a vacuum.

7. The joint positioning method of a dual-satellite-based real-time precise single-point positioning system according to claim 1, characterized in that, Step 6, which involves checking the consistency of clock bias types between consecutive epochs for satellite-based clock biases, also includes: Mark the type of clock correction used by each GPS satellite in the current epoch i; For each satellite in the subset, check if the label of the current epoch is the same as the label of the previous epoch; If they are the same, it means that the clock correction type used by the satellite at different epochs is consistent; if they are different, it means that the clock correction type used by the satellite at different epochs is inconsistent, and the ambiguity parameters of the satellite should be reset.

8. A dual-satellite-based real-time precise single-point positioning system combined with a positioning system, characterized in that, include: The first main module is used to acquire and decode the synchronously received PPP-B2b and Galileo HAS navigation enhancement message information, match the satellite-based augmentation orbit and clock correction with the corresponding broadcast ephemeris orbit and clock products, and recover the complete and precise satellite orbit and satellite clock products of all available satellites in the current epoch. The second main module is used to construct a common satellite subset of the real-time correction products provided by Beidou PPP-B2b and Galileo HAS in the current epoch, and to preprocess the orbit products of the common satellite subset to remove anomalies, so as to obtain "clean" orbit products of the common satellite subsets of the two satellite-based PPP systems. The third main module is used to generate a combined orbit of public satellites based on a subset of public satellites, and to calculate the coordinate reference transformation parameters between the combined orbit product of the public satellite subset and the satellite-based PPP orbit product. The fourth main module is used to convert the orbital products of all non-public satellites to the same coordinate reference frame as the combined orbital products of public satellites using the calculated coordinate reference transformation parameters. The fifth main module is used to correct the differences between the combined orbit and the B2b / HAS orbit to their respective satellite clock products; The sixth main module is used to perform a clock error type consistency check between previous and subsequent epochs on the satellite-based clock error when the clock error correction number used for positioning in the dual-satellite system changes, and to reset the ambiguity of satellites that fail the check. The seventh main module is used to achieve precise positioning of the joint dual-satellite-based PPP system using the provided corrected precision orbit and clock error corrections.

9. An electronic device, characterized in that, The system includes a memory and a processor, wherein the memory stores program instructions that are executed by the processor, and the processor invokes the program instructions to execute a joint positioning method for a dual-satellite-based real-time precise single-point positioning system as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions that cause the computer to execute the joint positioning method of a dual-satellite-based real-time precise single-point positioning system as described in any one of claims 1 to 7.

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