PPP-rtk positioning service method and system based on crowdsourcing mode

Abstract

The present application relates to the technical field of GNSS positioning, and particularly relates to a PPP-RTK positioning service method and system based on a crowdsourcing mode. The method comprises the following steps: obtaining an initial user station approximate position and a first satellite product, and observing to generate first original observation data; using ionosphere-free combinations and satellite product iteration to solve a first observation equation to obtain a solution position and register as a crowdsourcing user station; subsequently, inverse calculation is performed to generate initial user correction numbers; an initial user station approximate position, surrounding multi-source user correction numbers, a second satellite product and a reference station solution position are obtained, and second original observation data is generated by observation; multi-source correction numbers are spatially interpolated and observation data is corrected; a solution position is obtained by iteration according to a second observation equation; and user enhanced correction numbers are generated by correction of the multi-source correction numbers. The present application can have the global accuracy of PPP and the rapid convergence advantage of RTK. Direct data exchange between user stations is realized through a C2C link, and the service center load is significantly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of GNSS positioning technology, in particular to a PPP-RTK positioning service method and system based on a crowdsourcing mode. BACKGROUND

[0002] PPP-RTK (Precise Point Positioning - Real-Time Kinematic, precise point positioning - real-time kinematic differential technology) or network RTK (Real-Time Kinematic, real-time kinematic carrier phase differential technology) model can provide rapid and high-precision positioning services for users within the coverage area of the dense reference user station network, by means of the UPD (Uncalibrated Phase Delays, uncalibrated phase delay) and atmospheric delay correction products generated by the reference user station network. Users rely on the surrounding reference user stations to provide a variety of correction information in real time and continuously to accurately eliminate various error sources in the observation data. The quality of the atmospheric delay correction number is directly related to the distance between the user and the adjacent reference user station. Therefore, the positioning performance of the regional enhancement positioning service is directly limited by the density and spatial location layout of the reference user station network. When the user is in an area where the reference user station network is sparse, or is completely outside the network coverage, the accuracy of the positioning result will be significantly affected due to the precision limitation of the interpolation (or extrapolation) processing of the atmospheric correction parameters in these weak service areas, thereby weakening the availability, reliability and practical application value of high-precision positioning service. In addition, in order to expand the service range or densify the station network of the traditional regional enhancement positioning service model, the conventional strategy is to add reference user stations in the target area. However, this not only increases the construction and operation burden of the service provider, but also is particularly costly when deploying permanent reference user stations to meet occasional or temporary service needs.

[0003] In addition, in the traditional model, due to the restriction of the real-time link communication capability between devices and the limitation of server operation load, the effective enhancement information in the user observation data is often not fully extracted and effectively utilized. The introduction of the cooperative enhancement information of the adjacent user can theoretically obtain more significant enhancement benefits compared to the service provided by the distant reference user station. At the same time, in addition to the extensive communication data services provided by the mobile cellular network with an increasingly expanding range, the low-orbit communication satellite system under construction will also become a key infrastructure to meet the needs of two-way data communication of the cooperative enhancement model in the future. SUMMARY

[0004] The technical problem to be solved by the embodiments of the present application is to provide a PPP-RTK positioning service method and system based on a crowdsourcing mode, so as to solve the problem that the traditional regional enhanced positioning service model in the prior art has the above limitations.

[0005] The present application discloses a PPP-RTK positioning service method based on a crowdsourcing mode, comprising:

[0006] An initial user station is obtained, and a first satellite product broadcast by a service center is obtained, and first raw observation data is generated according to satellite signal observation from a GNSS;

[0007] A first observation equation is established, and the first observation equation is iteratively solved according to ionosphere-free combinations of the first raw observation data and the first satellite product, so as to obtain a calculated position of the initial user station and register the service center as a crowdsourcing user station;

[0008] The calculated position of the initial user station, the first raw observation data and the first satellite product are inversely calculated to obtain initial user corrections including tropospheric corrections, pseudorange and phase ionospheric corrections, and the initial user corrections that pass the test and are marked with quality are broadcast to surrounding crowdsourcing user stations through a C2C link;

[0009] The initial user station is obtained, and a first satellite product broadcast by a service center is obtained, and first raw observation data is generated according to satellite signal observation from a GNSS;

[0010] The position coordinate difference between the crowdsourcing user station and the reference user station is obtained, the received multi-source user corrections are interpolated in combination with the number of surrounding reference user stations, and the interpolated multi-source user corrections are used to correct the second raw observation data;

[0011] The second observation equation is established according to the multi-source user corrections marked with different quality, and the second observation equation is iteratively solved according to the corrected second raw observation data and the second satellite product, so as to obtain a calculated position of the crowdsourcing user station and broadcast the service center;

[0012] The user enhanced corrections of the crowdsourcing user station are obtained by correcting and inversely calculating the interpolated multi-source user corrections according to the calculated position of the crowdsourcing user station, the second raw observation data and the second satellite product, and the user enhanced corrections that pass the test and are marked with quality are broadcast to surrounding crowdsourcing user stations through a C2C link.

[0013] Optionally, the establishing the first observation equation, iteratively solving the first observation equation according to the ionosphere-free combination of the first raw observation data and the first satellite product, comprises:

[0014] The first observation equation group is established, and a functional expression of the first observation equation group is:

[0015]

[0016] In the formula, is a satellite identifier, is an ionosphere-free combination, is the speed of light in a vacuum, is a pseudo-range observation value of a satellite ionosphere-free combination, is a clock error of a satellite ionosphere-free combination, is a user-solved position range, is a clock error of a user receiver ionosphere-free combination, is a constant bias of an initial user station receiver simultaneously receiving different navigation system signals, is an oblique troposphere delay, is a pseudo-range observation noise of a satellite ionosphere-free combination, is an equivalent wavelength of an ionosphere-free combination, is a phase observation value of a satellite ionosphere-free combination, is a floating ambiguity of a satellite ionosphere-free combination phase observation, is a phase observation noise of a satellite ionosphere-free combination;

[0017] The first raw observation data is transformed into ionosphere-free combination observation values, and orbit and clock error products and UPD products are extracted from the first satellite product;

[0018] The ionosphere-free combination observation values, the orbit and clock error products are substituted into the first observation equation, and multi-epoch iterative calculation is performed on the first observation equation based on a filtering algorithm, so that the solved position, receiver clock error and floating ambiguity of the initial user station are gradually converged and solved;

[0019] The floating ambiguity is fixed as an integer ambiguity by using the extracted UPD product, the first observation equation is re-solved according to the integer ambiguity, and the optimal solved position of the initial user station is obtained.

[0020] Optionally, the PPP-RTK positioning service method further comprises, after the solved position of the initial user station is solved, inversely calculating the initial user correction number and performing verification marking, comprising:

[0021] An inversion equation group of the initial user correction number is established, and a function expression of the inversion equation group is:

[0022]

[0023] In the formula, is a troposphere delay correction number of the initial user station for solving a position, is a pseudo-range ionosphere delay correction number of the initial user station for solving the position at the i-th frequency point, is an original pseudo-range observation value of the satellite at the i-th frequency point, is a phase ionosphere delay correction number of the initial user station for solving the position at the i-th frequency point, is an electromagnetic wave wavelength of the i-th frequency point, is an original ambiguity of the satellite at the i-th frequency point, is an original phase observation value of the satellite at the i-th frequency point, is an identification of a signal frequency;

[0024] The initial user correction number is calculated by substituting the solved position of the initial user station, the floating-point ambiguity, the receiver clock difference, and the first original observation data into the inversion equation, and the initial user correction number includes the troposphere correction number, the pseudo-range and phase ionosphere correction number;

[0025] Based on a satellite-ground distance deviation of the solved position of the initial user station and a real position, an error transfer model of the satellite-ground distance deviation transferred in the initial user correction number is established, and a function expression of the error transfer model is:

[0026]

[0027] In the formula, is a troposphere delay correction number of the real position of the initial user station, is a pseudo-range ionosphere delay correction number of the real position of the initial user station at the i-th frequency point, is the satellite-ground distance deviation, is a satellite-ground distance of the real position of the user station, is a phase ionosphere delay correction number of the real position of the initial user station at the i-th frequency point;

[0028] An influence degree of the satellite-ground distance deviation on the initial user correction number in the error transfer model is evaluated, quality inspection is performed on the initial user correction number according to an evaluation result, and a first type of quality mark is generated for the initial user correction number passing the quality inspection, and a second type of quality mark with a quality degree lower than the first type of quality mark is generated.

[0029] Optionally, the step of obtaining the position coordinate difference between the crowd-sourced user station and the reference user station, and interpolating the received multi-source user correction number in combination with the number of surrounding reference user stations, comprises:

[0030] According to the approximate position of the crowd-sourced user station and the calculated position of the reference user station broadcast by the service center, the position coordinate difference between the crowd-sourced user station and the reference user station is calculated, wherein the reference user station comprises the initial user station, other crowd-sourced user stations and existing CORS reference user stations.

[0031] According to the number of surrounding reference user stations, a corresponding low-order curved surface interpolation model is established, and the function expression of the low-order curved surface interpolation model is:

[0032]

[0033]

[0034] In the formula, sat is a satellite identifier, is a satellite identifier, is an approximate position of a crowd-sourced user station, is an interpolated ionospheric delay correction number according to the approximate position of the crowd-sourced user station, is an interpolated tropospheric delay correction number according to the approximate position of the crowd-sourced user station, is a coefficient of the low-order curved surface interpolation model, is a coordinate difference between the crowd-sourced user station and the reference user station in the X-axis direction, is a coordinate difference between the crowd-sourced user station and the reference user station in the Y-axis direction, is a height difference between the crowd-sourced user station and the reference user station, is the number of surrounding broadcast reference user stations;

[0035] By performing least square fitting on the position coordinate difference and the multi-source user correction number, each coefficient in the low-order curved surface interpolation model is determined.

[0036] The position coordinate difference is substituted into the low-order curved surface interpolation model after the coefficients are determined, and the interpolated multi-source user correction number is obtained.

[0037] Optionally, the step of correcting the second original observation data by using the interpolated multi-source user correction number comprises:

[0038] A correction equation group of the original observation data is established, and the function expression of the correction equation group is:

[0039]

[0040] In the formula, sat is a satellite identifier, is the original pseudo-range observation of the satellite at the i-th frequency point after correction, is the original pseudo-range observation of the satellite at the i-th frequency point before correction, is the ionospheric delay correction of the pseudo-range at the i-th frequency point interpolated according to the approximate position of the crowd-sourced user station, is the speed of light in vacuum, is the satellite clock bias, is the wavelength of the electromagnetic wave at the i-th frequency point, is the original phase observation of the satellite at the i-th frequency point after correction, is the original phase observation of the satellite at the i-th frequency point before correction, is the ionospheric delay correction of the phase at the i-th frequency point interpolated according to the approximate position of the crowd-sourced user station;

[0041] The second original observation data after correction is obtained by substituting the interpolated multi-source user correction number into the correction equation set.

[0042] Optionally, the PPP-RTK positioning service method further comprises calculating the resolved position of the crowd-sourced user station after the second original observation data is corrected, comprising:

[0043] If the multi-source user correction number is marked with the first type of quality mark, the second observation equation is established, and the functional expression of the second observation equation is:

[0044]

[0045] If the multi-source user correction number is marked with the second type of quality mark, the second observation equation is established, and the functional expression of the second observation equation is:

[0046]

[0047] In the formula, is the user resolved position, is the receiver clock bias of the crowd-sourced user station, is the ionospheric delay coefficient related to frequency at the i-th frequency point, is the slant ionospheric delay according to the approximate position of the crowd-sourced user station, is the projection function of the zenith tropospheric delay mapped to the satellite slant path direction, is the satellite elevation angle, is the zenith tropospheric delay, is the pseudo-range observation noise of the satellite at the i-th frequency point, is the phase observation noise of the satellite at the i-th frequency point, is the floating-point ambiguity of the phase observation of the satellite at the i-th frequency point;

[0048] extracting an orbit and clock error product and a UPD product from the second satellite product, substituting the corrected second original observation data, the orbit and clock error product and the UPD product into the corresponding second observation equation according to the quality marks of the multi-source user corrections, and performing multi-epoch iterative calculation on the second observation equation based on a filtering algorithm to gradually converge and solve the calculated position, receiver clock error and floating ambiguity of the crowd-sourced user station;

[0049] fixing the calculated floating ambiguity as an integer ambiguity using the extracted UPD product, and re-solving the second observation equation according to the integer ambiguity to obtain the optimal calculated position of the crowd-sourced user station.

[0050] Optionally, the PPP-RTK positioning service method further comprises, after the calculated position of the crowd-sourced user station is solved, correcting and inverting the interpolated multi-source user corrections to obtain user enhanced corrections of the crowd-sourced user station and performing a quality mark, comprising:

[0051] According to the interpolated tropospheric delay correction, adding the tropospheric delay residual error in the calculation process of the calculated position of the crowd-sourced user station, and calculating the tropospheric enhanced delay correction of the crowd-sourced user station, the calculation function expression of the tropospheric enhanced delay correction is:

[0052]

[0053] In the formula, is the tropospheric enhanced delay correction of the calculated position of the crowd-sourced user station;

[0054] The sliding time window is used to perform multi-epoch smoothing processing on the tropospheric enhanced delay correction, and the function expression of the smoothing processing is:

[0055]

[0056] In the formula, is the smoothed tropospheric delay, is the index of the target epoch, represents the number of epochs taken before and after the target epoch in the time window, represents the index of any epoch;

[0057] According to the calculated position, receiver clock error and floating ambiguity of the crowd-sourced user station, and the second original observation data after correction, the ionospheric correction value at the calculated position of the crowd-sourced user station is calculated in combination with the smoothed tropospheric delay, and the calculation function expression of the ionospheric correction value is:

[0058]

[0059] wherein, is a pseudorange ionosphere correction value at the position of the crowdsourcing user station, is a satellite ionosphere-free combined clock error, is a user receiver ionosphere-free combined clock error, is a phase ionosphere correction value at the position of the crowdsourcing user station;

[0060] The ionosphere correction value is used to correct the interpolated ionosphere delay correction number to obtain an ionosphere enhanced delay correction number of the crowdsourcing user station, and a calculation function expression of the ionosphere enhanced delay correction number is:

[0061]

[0062] wherein, is a pseudorange troposphere enhanced delay correction number at the position of the crowdsourcing user station, is an interpolated pseudorange ionosphere delay correction number at the i-th frequency point according to the approximate position of the crowdsourcing user station, is a phase troposphere enhanced delay correction number at the position of the crowdsourcing user station, is an interpolated phase ionosphere delay correction number at the i-th frequency point according to the approximate position of the crowdsourcing user station;

[0063] The user enhanced correction number is subjected to quality inspection, and the first type of quality mark and the second type of quality mark are generated for the user enhanced correction number passing the quality inspection according to the inspection result.

[0064] Optionally, the PPP-RTK positioning service method further comprises data communication between the user and the surrounding users, comprising:

[0065] The approximate position of the initial user station is sent to the service center, and satellite products and a service list of surrounding registered crowdsourcing user stations are broadcast to the receiver of the initial user station by the service center according to the approximate position, wherein the service list comprises the calculated position and IP address of the crowdsourcing user station;

[0066] According to the service list returned by the service center, a batch of adjacent crowdsourcing user stations are selected by the initial user station and a data request is sent;

[0067] In response to the data request of the initial user station, enhanced information comprising atmospheric delay correction numbers is generated in real time by the requested crowdsourcing user stations, and is sent back to the initial user station through a C2C link;

[0068] According to the satellite products broadcast by the service center and the enhanced information returned by the requested crowdsourcing user stations, the position of the initial user station is calculated;

[0069] When the position solution of the initial user station is completed and converges stably, the solved position and IP address of the initial user station are reported to the service center to register as a crowdsourcing user station.

[0070] The application further discloses a positioning service system adopting the PPP-RTK positioning service method based on the crowdsourcing mode.

[0071] A satellite information broadcasting module is configured to acquire the approximate position of an initial user station and a first satellite product broadcast by a service center, and generate first raw observation data based on satellite signal observation from a GNSS;

[0072] An initial user station position solution module is configured to establish a first observation equation, iteratively solve the first observation equation based on ionosphere-free combinations of the first raw observation data and the first satellite product, and obtain a solved position of the initial user station and report the service center to register as a crowdsourcing user station;

[0073] An initial user correction number generation module is configured to perform inversion calculation on the solved position of the initial user station, the first raw observation data and the first satellite product, obtain initial user correction numbers including tropospheric correction numbers, pseudo-range and phase ionospheric correction numbers, and broadcast the initial user correction numbers that pass the test and are marked with a quality mark to surrounding crowdsourcing user stations through a C2C link;

[0074] A satellite and user information broadcasting module is configured to acquire the approximate position of a crowdsourcing user station, multi-source user correction numbers broadcast by surrounding reference user stations, a second satellite product broadcast by the service center and a solved position of the reference user stations, and generate second raw observation data based on satellite signal observation from a GNSS;

[0075] An observation data correction module is configured to acquire the position coordinate difference between the crowdsourcing user station and the reference user stations, interpolate the received multi-source user correction numbers in combination with the number of surrounding reference user stations, and correct the second raw observation data using the interpolated multi-source user correction numbers;

[0076] A crowdsourcing user station position solution module is configured to establish a second observation equation based on the multi-source user correction numbers marked with different quality marks, iteratively solve the second observation equation based on the corrected second raw observation data and the second satellite product, and obtain a solved position of the crowdsourcing user station and report the service center;

[0077] The crowd-sourcing user station correction number generation module is configured to correct and inverse the interpolated multi-source user correction number according to the resolved position of the crowd-sourcing user station, the second original observation data and the second satellite product, to obtain user enhanced correction number of the crowd-sourcing user station, and to broadcast the user enhanced correction number that passes the test and is marked by quality to surrounding crowd-sourcing user stations through a C2C link.

[0078] The application further discloses a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the PPP-RTK positioning service method based on the crowd-sourcing mode.

[0079] Compared with the prior art, the PPP-RTK positioning service method and system based on the crowd-sourcing mode have the following advantages:

[0080] The crowd-sourcing PPP-RTK model effectively overcomes the dependence of the traditional regional enhanced positioning service on the dense reference station network, realizes direct broadcasting of user correction numbers between users by using a C2C link, and greatly reduces the construction and operation costs. The initial user station generates initial user correction numbers by inverse calculation, and the crowd-sourcing user station fuses multi-source user correction numbers, and then generates user enhanced correction numbers by quickly resolving positions in combination with the differentiated second observation equation after interpolation and correction. BRIEF DESCRIPTION OF DRAWINGS

[0081] The technical solutions of the application will be further described in detail below with reference to the drawings and embodiments. In the drawings:

[0082] Figure 1 A step schematic block diagram of the PPP-RTK positioning service method provided by the embodiments of the application is shown in the figure.

[0083] Figure 2 A data processing flow schematic diagram of the PPP-RTK positioning service method provided by the embodiments of the application is shown in the figure.

[0084] Figure 3 A principle schematic diagram of introducing satellite-earth distance bias in the error transfer model provided by the embodiments of the application is shown in the figure.

[0085] Figure 4 A schematic diagram of data communication between a user and surrounding users provided by the embodiments of the application is shown in the figure. DETAILED DESCRIPTION

[0086] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The preferred embodiments of the application will be described in detail with reference to the drawings.

[0087] The application discloses a PPP-RTK positioning service method based on a crowdsourcing mode, as shown in Figure 1 and Figure 2 The method comprises the following steps.

[0088] S1, obtaining the approximate position of an initial user station and a first satellite product broadcast by a service center, and generating first raw observation data according to satellite signal observation from a GNSS;

[0089] S2, establishing a first observation equation, iteratively solving the first observation equation according to ionosphere-free combinations of the first raw observation data and the first satellite product, obtaining the calculated position of the initial user station and reporting the service center to register as a crowdsourcing user station;

[0090] S3, performing inversion calculation on the calculated position of the initial user station, the first raw observation data and the first satellite product, obtaining initial user corrections including tropospheric corrections, pseudorange and phase ionospheric corrections, and broadcasting the initial user corrections that pass the test and are marked with quality to surrounding crowdsourcing user stations through a C2C link;

[0091] S4, obtaining the approximate position of a crowdsourcing user station, multi-source user corrections broadcast by surrounding reference user stations, a second satellite product broadcast by the service center and the calculated position of the reference user station, and generating second raw observation data according to satellite signal observation from the GNSS;

[0092] S5, obtaining the position coordinate difference between the crowdsourcing user station and the reference user station, interpolating the received multi-source user corrections in combination with the number of surrounding reference user stations, and correcting the second raw observation data by using the interpolated multi-source user corrections;

[0093] S6, establishing a differentiated second observation equation according to multi-source user corrections with different quality marks, iteratively solving the second observation equation according to the corrected second raw observation data and the second satellite product, obtaining the calculated position of the crowdsourcing user station and reporting the service center;

[0094] S7, correcting and inverting the interpolated multi-source user corrections according to the calculated position of the crowdsourcing user station, the second raw observation data and the second satellite product, obtaining user enhanced corrections of the crowdsourcing user station, and broadcasting the user enhanced corrections that pass the test and are marked with quality to surrounding crowdsourcing user stations through a C2C link.

[0095] Through the implementation of the above-mentioned PPP-RTK positioning service method embodiment, first, the initial user station's approximate position and the first satellite product broadcast by the service center are obtained, and the first raw observation data is generated by the receiver of the initial user station autonomously receiving the satellite signal of the GNSS (Global Navigation Satellite System) to lay the data foundation for positioning calculation. By establishing the first observation equation, the ionosphere-free combination observation value and the satellite product are used for iterative PPP calculation to obtain the accurate calculation position of the initial user station and register it as a crowd-sourced user station to ensure the reliability of system initialization. Subsequently, the calculation position of the initial user station, the observation data and the satellite product are calculated inversely to obtain the initial user correction number (i.e. atmospheric delay correction number) containing the troposphere, pseudorange and phase ionosphere after the parameters converge stably, the quality tested and marked correction numbers are packaged to obtain the crowd-sourced PPP-RTK correction number product, and the product is broadcast to the surrounding users through the C2C (Client to Client) link to form a preliminary enhanced information network.

[0096] For the crowd-sourced user station, the system obtains its approximate position, the multi-source user correction number broadcast by the surrounding reference user station, and the second satellite product and the reference station calculation position provided by the service center, and the second raw observation data is generated by the receiver of the crowd-sourced user station autonomously receiving the satellite signal of the GNSS to build a complete data input system. By calculating the position coordinate difference between the crowd-sourced user station and the reference user station, and combining the number of surrounding reference stations to interpolate the multi-source user correction number, the interpolated correction number is used to correct the second raw observation data, which can effectively compensate the spatial correlation error. According to the different quality marked multi-source user correction number, a differentiated second observation equation is established, the corrected observation data and the satellite product are used for iterative PPP-RTK calculation to obtain the accurate calculation position of the crowd-sourced user station, and the positioning accuracy under different quality data is ensured.

[0097] Finally, according to the calculated position, observation data and satellite product of the crowd-sourcing user station, the residual amount of troposphere delay is introduced to further correct the multi-source user correction number, and the enhanced correction number of the user is generated. These enhanced correction numbers which are strictly quality tested and marked are packaged to obtain the crowd-sourcing PPP-RTK correction number product, and are broadcast to the surrounding users through the C2C link to form a continuously optimized enhanced information flow. Thus, the organic integration of PPP and RTK technology is realized through the crowd-sourcing mode: on the one hand, the precise point positioning technology is used to process the global errors such as satellite orbit and clock error, and on the other hand, the local enhanced correction number provided by the crowd-sourcing user station is used to realize rapid ambiguity fixing, so as to have the global accuracy of PPP and the rapid convergence advantage of RTK. And through the C2C link, direct data exchange between user stations is realized, which significantly reduces the load of the service center, so as to ensure the reliability and adaptability of the positioning service through quality grading and differential processing, and provides an effective technical solution for large-scale high-precision positioning application.

[0098] As described above, the satellite product mainly includes orbit, clock error and UPD product. The precise orbit product is used to provide the accurate three-dimensional coordinates of each GNSS satellite at any time; the precise clock error product is used to provide the accurate clock error between each satellite clock and the system reference time; and the UPD product is used to provide the correction number for eliminating the hardware delay, so that the ambiguity is fixed to an integer.

[0099] Further, a first observation equation is established, and the first observation equation is iteratively solved according to the ionosphere-free combination of the first original observation data and the first satellite product, including:

[0100] A first observation equation set is established, and the functional expression of the first observation equation set is:

[0101]

[0102] In the formula, c is the speed of light in vacuum, is a satellite identifier, is an ionosphere-free combination, is the speed of light in vacuum, is a pseudo-range observation value of the satellite ionosphere-free combination, is a clock error of the satellite ionosphere-free combination, is a user calculated position, is a clock error of the user receiver ionosphere-free combination, is a constant bias of the initial user station receiver receiving signals of different navigation systems at the same time, is an oblique troposphere delay, is a pseudo-range observation noise of the satellite ionosphere-free combination, is an equivalent wavelength of the ionosphere-free combination, is a phase observation value of the satellite ionosphere-free combination, a float ambiguity of a satellite ionosphere-free combined phase observation, a noise of a satellite ionosphere-free combined phase observation,

[0103] transforming the first original observation data into ionosphere-free combined observation values, and extracting orbit and clock error products and UPD products from the first satellite products;

[0104] substituting the ionosphere-free combined observation values, the orbit and clock error products into the first observation equation, and performing multi-epoch iterative calculation on the first observation equation based on a filtering algorithm, gradually converging and solving out the solved position of the initial user station, the receiver clock error and the float ambiguity;

[0105] fixing the solved float ambiguity as an integer ambiguity by using the extracted UPD products, and re-solving the first observation equation according to the integer ambiguity to obtain the optimal solved position of the initial user station.

[0106] Through the implementation of the above-mentioned PPP-RTK positioning service method embodiment, the first observation equation set is established, and the ionosphere-free combination can effectively eliminate the main influence of ionosphere delay on positioning solution, so as to improve the precision and stability of parameter estimation. Therefore, by converting the first original observation data into ionosphere-free combined observation values and fusing the precise orbit and clock error products in the first satellite products, a data foundation is laid for high-precision positioning. After substituting the above-mentioned data into the first observation equation, a filtering algorithm is used for multi-epoch iterative calculation, and the solved position of the initial user station, the receiver clock error and the float ambiguity and other key parameters are gradually converged and solved out, which can improve the reliability and convergence speed of parameter solution. Finally, by introducing the UPD product to fix the float ambiguity as an integer ambiguity, and re-solving the first observation equation, the optimal solved position of the initial user station is obtained, which finally ensures that the initial user station can quickly obtain a high-precision and high-reliability solved position, and provides a solid data foundation for subsequent provision of crowd-sourced enhanced information. Among them, the UPD product together with the precise orbit and clock error is broadcast by the service center, and users are encouraged to correctly fix the ambiguity as much as possible. By fixing the ambiguity, the initial user can obtain a high-precision dynamic position solution.

[0107] Further, the PPP-RTK positioning service method further includes, after solving out the solved position of the initial user station, inversely calculating the initial user correction number and performing inspection marking, including:

[0108] establishing an inverse equation set of the initial user correction number, and the functional expression of the inverse equation set is:

[0109]

[0110] In the formula, is the troposphere delay correction number of the solved position of the initial user station, a pseudo-range ionospheric delay correction number at the i-th frequency point for the initial user station to solve the position, an original pseudo-range observation value of the satellite at the i-th frequency point, a phase ionospheric delay correction number at the i-th frequency point for the initial user station to solve the position, an electromagnetic wave wavelength at the i-th frequency point, an original ambiguity of the satellite at the i-th frequency point, an original phase observation value of the satellite at the i-th frequency point, an identification of a signal frequency;

[0111] the initial user correction number includes a tropospheric correction number, a pseudo-range ionospheric correction number and a phase ionospheric correction number.

[0112] an error transfer model of the satellite-ground distance deviation being transferred in the initial user correction number is established based on the satellite-ground distance deviation between the initial user station position solved and the real position, and a function expression of the error transfer model is:

[0113]

[0114] in the formula, a tropospheric delay correction number at the real position of the initial user station, a pseudo-range ionospheric delay correction number at the i-th frequency point for the real position of the initial user station, a satellite-ground distance deviation, a satellite-ground distance at the real position of the user station, a phase ionospheric delay correction number at the i-th frequency point for the real position of the initial user station;

[0115] an influence degree of the satellite-ground distance deviation on the initial user correction number in the error transfer model is evaluated, the initial user correction number is quality inspected according to the evaluation result, and a first type quality mark is generated for the initial user correction number passing the quality inspection, and a second type quality mark with a quality degree lower than the first type quality mark.

[0116] By implementing the above PPP-RTK positioning service method embodiment, the initial user correction number inversion equation set and the error transfer model are established, and high-precision estimation and reliability control of the atmospheric delay error are realized. Specifically, the inversion equation set is used to systematically solve the tropospheric delay correction number of the initial user station, the ionospheric delay correction number at each frequency point, and the phase ionospheric delay correction number, thereby providing complete atmospheric correction information for subsequent broadcasting. By introducing the satellite-geodetic distance deviation parameter to establish the error transfer model, the influence degree of the calculated position error on various correction numbers is quantified. Based on the model, the quality of the initial user correction number is inspected, and a differentiated quality mark is generated according to the influence evaluation result of the satellite-geodetic distance deviation, including a first type of quality mark and a second type of quality mark, to ensure the reliability and usability of the correction number information. Thus, a complete quality control closed loop is formed, which not only fully utilizes the enhancement potential of the initial user station as a dynamic reference station, but also ensures the reliability of the enhanced information through a strict quality control mechanism, thereby laying a foundation for the effective utilization of atmospheric correction information in the crowdsourcing PPP-RTK system and improving the precision and robustness of the entire positioning service system. The necessary condition for generating the initial user correction number is that the parameters are sufficiently converged and stable, and it is not necessary to fix the ambiguity.

[0117] As described above, the biggest difference between the estimation of atmospheric delay correction number of the embodiment method of the present application and the traditional model is the satellite-geodetic distance. Since the real-time dynamic coordinates of the user can only be obtained by estimation, they are not accurate known values, and errors are inevitably introduced into the calculation. As shown in the following formula, assuming that the real position and the calculated position of the initial user station receiver are Figure 3 and , for a satellite located at S1 (S2) position, the real and calculated satellite-geodetic distances are represented as PS1 (PS2) and , respectively, and are denoted as and . On the PS1 (PS2) line, make d1 (d2) points such that d1S1= S1 (d2S2= S2), then Pd1 (d2) is the satellite-geodetic distance of the S1 (S2) satellite caused by the deviation of the calculation error, that is:

[0118]

[0119] In the formula, δ is the satellite-geodetic distance deviation, P is the satellite-geodetic distance of the user station real position, and P' is the satellite-geodetic distance of the user calculated position.

[0120] ​​​​​​The value of the satellite-geodetic distance deviation is related to the coordinate error, satellite height, azimuth angle and elevation angle, and is difficult to accurately predict, so it is necessary to perform quality inspection on the correction number generated by the user station.

[0121] Further, the position coordinate difference between the crowd-sourced user station and the reference user station is obtained, and the received multi-source user correction number is interpolated in combination with the number of surrounding reference user stations, including:

[0122] According to the approximate position of the crowd-sourced user station and the calculated position of the reference user station broadcast by the service center, the position coordinate difference between the crowd-sourced user station and the reference user station is calculated, and the reference user station includes an initial user station, other crowd-sourced user stations and existing CORS reference user stations (Continuously Operating Reference Station);

[0123] According to the number of surrounding reference user stations, a corresponding low-order curved surface interpolation model is established, and the function expression of the low-order curved surface interpolation model is:

[0124]

[0125]

[0126] In the formula, is a satellite identifier, is an approximate position of the crowd-sourced user station, is an ionospheric delay correction number interpolated according to the approximate position of the crowd-sourced user station, is a tropospheric delay correction number interpolated according to the approximate position of the crowd-sourced user station, is a coefficient of the low-order curved surface interpolation model, is a coordinate difference between the crowd-sourced user station and the reference user station in the X-axis direction, is a coordinate difference between the crowd-sourced user station and the reference user station in the Y-axis direction, is a height difference between the crowd-sourced user station and the reference user station, is the number of surrounding broadcast reference user stations;

[0127] By performing least square fitting on the position coordinate difference and the multi-source user correction number, each coefficient in the corresponding low-order curved surface interpolation model is determined;

[0128] The position coordinate difference is substituted into the low-order curved surface interpolation model with the determined coefficients to obtain the interpolated multi-source user correction number.

[0129] Further, the interpolated multi-source user correction number is used to correct the second original observation data, including:

[0130] The correction equation set of the original observation data is established, and the function expression of the correction equation set is:

[0131]

[0132] In the formula, is the original pseudo-range observation value of the satellite at the i-th frequency point after correction, is the original pseudo-range observation value of the satellite at the i-th frequency point before correction, is the pseudo-range ionospheric delay correction value at the i-th frequency point after interpolation according to the approximate position of the crowd-sourcing user station, is the speed of light in vacuum, is the satellite clock error, is the wavelength of the electromagnetic wave at the i-th frequency point, is the original phase observation value of the satellite at the i-th frequency point after correction, is the original phase observation value of the satellite at the i-th frequency point before correction, is the phase ionospheric delay correction value at the i-th frequency point after interpolation according to the approximate position of the crowd-sourcing user station;

[0133] The interpolated multi-source user correction value is substituted into the correction equation set to obtain the second original observation data after correction.

[0134] Through the implementation of the above-mentioned PPP-RTK positioning service method embodiment, the position coordinate difference , and the height difference are accurately calculated based on the approximate position of the crowd-sourcing user station and the calculated position of the reference user station broadcast by the service center, and the spatial geometric relationship foundation is established. According to the number of the surrounding broadcast reference user stations, the low-order curved surface interpolation model is intelligently selected: when n=3, the plane model is adopted; when n>3, the height factor is introduced to form a three-dimensional model, so as to ensure that the low-order curved surface interpolation model is highly consistent with the spatial characteristics of the atmospheric delay. Through the least square fitting of the position coordinate difference and the multi-source user correction value, the coefficients of the low-order curved surface interpolation model are accurately determined, and then the ionospheric delay correction value and the tropospheric delay correction value after interpolation of the approximate position of the crowd-sourcing user station are obtained. After obtaining the interpolated atmospheric delay correction value, the positioning calculation can be performed. The interpolated multi-source user correction value is substituted into the correction equation set to perform systematic correction on the second original observation data. The pseudo-range observation value is corrected by introducing and , and the phase observation value is corrected by introducing and , and the satellite clock error The influence of the first and second types of quality marks is removed, and the corrected original pseudorange observation value and original phase observation value are obtained. Thus, a complete data processing chain is formed to improve the spatial availability of multi-source user corrections and the quality of observation data, and to provide a reliable data basis for high-precision positioning calculation of the crowd-sourced PPP-RTK system.

[0135] The CORS reference user station is a component of a traditional fixed reference station network, and is usually deployed and maintained by an official or service provider. Because it is a permanent infrastructure, it can provide continuous and stable observation data and traditional corrections, thereby obtaining a traditional correction product.

[0136] Further, the PPP-RTK positioning service method further includes calculating the calculated position of the crowd-sourced user station after correcting the second original observation data, including:

[0137] If the multi-source user corrections have the first type of quality mark, a second observation equation is established, and the functional expression of the second observation equation is:

[0138]

[0139] If the multi-source user corrections have the second type of quality mark, a second observation equation is established, and the functional expression of the second observation equation is:

[0140]

[0141] In the formula, is the user calculated position, is the receiver clock bias of the crowd-sourced user station, is the ionospheric delay coefficient related to the frequency at the i-th frequency point, is the slant ionospheric delay at the approximate position of the crowd-sourced user station, is a projection function of the zenith tropospheric delay mapped to the satellite slant path direction, is the satellite elevation angle, is the zenith tropospheric delay, is the pseudorange observation noise of the satellite at the i-th frequency point, is the phase observation noise of the satellite at the i-th frequency point, is the float ambiguity of the phase observation of the satellite at the i-th frequency point;

[0142] The orbit and clock bias products and the UPD product are extracted from the second satellite product, the corrected second original observation data, the orbit and clock bias products are substituted into the corresponding second observation equation according to the quality mark of the multi-source user corrections, and the second observation equation is calculated by a filtering algorithm for multi-epoch iteration, so that the calculated position, the receiver clock bias and the float ambiguity of the crowd-sourced user station are gradually converged and calculated.

[0143] The extracted UPD product is used to fix the calculated floating-point ambiguity to integer ambiguity. The second observation equation is then recalculated based on the integer ambiguity to obtain the optimal solution position of the crowdsourcing user station.

[0144] Through the implementation of the above-described PPP-RTK positioning service method embodiment, the observation model is first intelligently selected based on the quality label of the multi-source user correction data; when the correction data carries a first-type quality label, the satellite-to-ground distance including the user's calculated location is used. Receiver clock bias Projection function and zenith tropospheric delay The simplified equation; when the second type of mass label is included, a frequency-dependent ionospheric delay coefficient is added. and oblique ionospheric delay Parameters are used to compensate for insufficient accuracy. Orbit and clock bias products extracted from the second satellite product, along with the UPD product and the corrected second original observation data, are substituted into the corresponding equations. Multi-epoch iterative calculations are performed based on a filtering algorithm, gradually converging to accurately calculate the solution location of the crowdsourced user station, receiver clock bias, and floating-point ambiguity. Finally, the floating-point ambiguity is fixed to integer ambiguity using the UPD product, and the second observation equation is recalculated to obtain the optimal solution location of the crowdsourced user station. This scheme achieves adaptive selection of the second observation model through quality labeling, ensures gradual parameter convergence through multi-epoch iteration, and ultimately achieves a leap in accuracy through ambiguity fixation, forming a complete high-precision positioning solution system. This greatly enhances the adaptability and positioning performance of the crowdsourced PPP-RTK system under different data quality conditions.

[0145] Furthermore, the PPP-RTK positioning service method also includes, after calculating the calculated location of the crowdsourced user station, correcting and inverting the interpolated multi-source user correction number to obtain the user enhancement correction number of the crowdsourced user station and performing verification marking, including:

[0146] Based on the interpolated tropospheric delay correction, and adding the residual error of the tropospheric delay from the crowdsourced user station location calculation process, the tropospheric enhancement delay correction for the crowdsourced user station is calculated. The calculation function expression for the tropospheric enhancement delay correction is as follows:

[0147]

[0148] In the formula, Calculate the tropospheric enhancement delay correction for the location of crowdsourced user stations;

[0149] Because of the use of the zenith troposphere and projection functions The accuracy of the interpolation is subject to the accuracy of the multi-source user correction number after interpolation and the accuracy of ambiguity fixing, so that abnormal outliers may be generated. The tropospheric delay is more stable than the ionospheric delay and generally does not fluctuate sharply in a short time, so a sliding time window can be used to smooth and eliminate outliers. That is:

[0150] The tropospheric delay correction number is smoothed for multiple epochs by using a sliding time window, and the function expression of the smoothing is:

[0151]

[0152] In the formula, is the smoothed tropospheric delay, is the index of the target epoch, represents the number of epochs taken before and after the target epoch within the time window, represents the index of any epoch;

[0153] After the second original observation data is corrected, the satellite clock error and the user station receiver clock error have been changed to ionosphere-free combinations, so:

[0154] According to the calculated position of the crowd-sourced user station, the receiver clock error, the floating ambiguity, and the corrected second original observation data, combined with the smoothed tropospheric delay, the ionospheric correction value at the calculated position of the crowd-sourced user station is calculated and calculated, and the function expression of the ionospheric correction value is:

[0155]

[0156] In the formula, is the ionospheric correction value of the pseudo-range at the calculated position of the crowd-sourced user station, is the clock error of the satellite ionosphere-free combination, is the clock error of the user receiver ionosphere-free combination, is the phase ionospheric correction value at the calculated position of the crowd-sourced user station;

[0157] The ionospheric correction value is used to correct the interpolated ionospheric delay correction number to obtain the ionospheric enhancement delay correction number of the crowd-sourced user station, and the function expression of the ionospheric enhancement delay correction number is:

[0158]

[0159] In the formula, is the pseudo-range tropospheric enhancement delay correction number at the calculated position of the crowd-sourced user station, is the interpolated pseudo-range ionospheric delay correction number at the i-th frequency point according to the approximate position of the crowd-sourced user station, a tropospheric enhancement delay correction number for crowd-sourcing user stations to solve positions, an interpolated phase ionospheric delay correction number at the i-th frequency point according to the approximate position of the crowd-sourcing user station;

[0160] quality inspection is performed on the user enhancement correction number, and a first type of quality mark and a second type of quality mark are generated for the user enhancement correction number passing the quality inspection according to the inspection result.

[0161] Through the implementation of the above-mentioned PPP-RTK positioning service method embodiment, unlike the initial user station, the crowd-sourcing user station has corrected the atmospheric delay error, so it is not necessary to construct the ionosphere-free combined observation value to estimate the correction number, but to estimate the residual atmospheric delay error in the observation value on the basis of the corrected observation value as the correction value of the interpolated atmospheric delay and combine the interpolated correction number into the accurate crowd-sourcing correction number.

[0162] Firstly, based on the interpolated tropospheric delay correction number, the tropospheric delay residual error calculated in the solving process of the crowd-sourcing user station is introduced, and the influence of the satellite elevation angle projection function is fully considered, so that the tropospheric enhancement delay correction number is accurately calculated, and the model error of the initial interpolated correction number is effectively compensated. Further, a sliding time window is used to perform multi-epoch smoothing processing on the correction number, and through the weighted average in the time domain, the random observation noise and short-term fluctuation can be effectively suppressed, and the stability and reliability of the correction number can be significantly improved. Subsequently, according to the accurate solving position, the receiver clock difference and the float ambiguity parameter of the crowd-sourcing user station, in combination with the corrected second original observation data and the smoothed tropospheric delay, the pseudo-range ionospheric correction value and the phase ionospheric correction value are respectively calculated through the corresponding function relationship, and the two correction values can accurately reflect the actual residual error of the ionospheric delay at the current solving position. Then, these ionospheric correction values are used to accurately correct the interpolated ionospheric delay correction number, so as to obtain the final ionospheric enhancement delay correction number, including the pseudo-range and phase enhancement correction numbers, so as to eliminate the error caused by interpolation. Finally, strict quality inspection is performed on the generated user enhancement correction number, and a first type of quality mark or a second type of quality mark is assigned according to the inspection result, so as to form a complete quality control closed loop. Thus, a complete atmospheric correction number optimization system is constructed, the precision and reliability of the atmospheric delay correction number in the crowd-sourcing PPP-RTK system are significantly improved, a solid technical support is provided for high-precision positioning service, and flexible data selection basis is provided for positioning applications with different precision requirements through the quality mark.

[0163] Further, in combination with Figure 4 It is shown that the PPP-RTK positioning service method further includes data communication between the user and the surrounding users, including:

[0164] sending the approximate position of the initial user station to the service center, and according to the approximate position, broadcasting satellite products and a service list of surrounding registered crowd-sourcing user stations to the receiver of the initial user station by the service center, the service list including the calculated positions and IP addresses of the crowd-sourcing user stations;

[0165] selecting a number of adjacent crowd-sourcing user stations according to the service list returned by the service center, and sending a data request by the initial user station;

[0166] in response to the data request of the initial user station, generating enhanced information including atmospheric delay corrections in real time by the requested crowd-sourcing user stations, and sending the enhanced information back to the initial user station through a C2C link;

[0167] calculating the position of the initial user station according to the satellite products broadcasted by the service center and the enhanced information returned by the requested crowd-sourcing user stations;

[0168] when the position calculation of the initial user station is completed and converges stably, registering the calculated position and IP address of the initial user station as a crowd-sourcing user station to the service center.

[0169] Through the implementation of the above-mentioned PPP-RTK positioning service method embodiment, first, the approximate position of the initial user station is sent to the service center, the service center broadcasts satellite products and a service list of surrounding registered crowd-sourcing user stations to the initial user station according to the approximate position, ensuring that the initial user can quickly obtain surrounding available enhanced resources. According to the calculated position and IP address information of the crowd-sourcing user stations included in the service list, the initial user station can intelligently select a number of adjacent crowd-sourcing user stations and send a data request, realizing accurate acquisition of enhanced information. The requested crowd-sourcing user stations generate enhanced information including atmospheric delay corrections in real time as collaborative users, and send the enhanced information back to the initial user station through a C2C link, which greatly reduces the computational load and data transmission delay of the service center. The initial user station combines the satellite products broadcasted by the service center and the enhanced information returned by the requested crowd-sourcing user stations to calculate the position, fully utilizing the complementary advantages of multi-source enhanced information, significantly accelerating the positioning convergence speed. When the position calculation of the initial user station is completed and converges stably, the real-time calculated position and IP address of the initial user station are registered as a crowd-sourcing user station to the service center, realizing the self-growth and self-expansion of the crowd-sourcing user group, forming a benign system ecological cycle. The entire communication process from approximate position uploading to service list acquisition, from data request to enhanced information return, and finally completing position calculation and user registration, not only significantly improves the coverage ability and initialization efficiency of the positioning service, but also enhances the reliability and stability of the entire system through the continuous expansion of the crowd-sourcing user group, providing a feasible technical solution for large-scale high-precision positioning services.

[0170] The application further discloses a positioning service system which adopts the PPP-RTK positioning service method based on the crowdsourcing mode.

[0171] A satellite information broadcasting module is used for acquiring the approximate position of the initial user station and the first satellite product broadcast by the service center, and generating first raw observation data according to satellite signal observation from the GNSS;

[0172] An initial user station position solving module is used for establishing a first observation equation, iteratively solving the first observation equation according to ionosphere-free combinations of the first raw observation data and the first satellite product, obtaining the solved position of the initial user station and reporting the service center to register as a crowdsourcing user station;

[0173] An initial user correction number generating module is used for performing inversion calculation on the solved position of the initial user station, the first raw observation data and the first satellite product, obtaining initial user correction numbers including tropospheric correction numbers, pseudorange and phase ionospheric correction numbers, and broadcasting the initial user correction numbers which pass the test and are marked with quality to the surrounding crowdsourcing user stations through the C2C link;

[0174] A satellite and user information broadcasting module is used for acquiring the approximate position of the crowdsourcing user station, the multi-source user correction numbers broadcast by the surrounding reference user stations, the second satellite product broadcast by the service center and the solved position of the reference user station, and generating second raw observation data according to satellite signal observation from the GNSS;

[0175] An observation data correction module is used for acquiring the position coordinate difference between the crowdsourcing user station and the reference user station, interpolating the received multi-source user correction numbers in combination with the number of the surrounding reference user stations, and correcting the second raw observation data by using the interpolated multi-source user correction numbers;

[0176] A crowdsourcing user station position solving module is used for establishing differential second observation equations according to multi-source user correction numbers marked with different quality, iteratively solving the second observation equations according to the corrected second raw observation data and the second satellite product, obtaining the solved position of the crowdsourcing user station and reporting the service center;

[0177] A crowdsourcing user station correction number generating module is used for correcting and inverting the interpolated multi-source user correction numbers to obtain user enhanced correction numbers of the crowdsourcing user station according to the solved position of the crowdsourcing user station, the second raw observation data and the second satellite product, and broadcasting the user enhanced correction numbers which pass the test and are marked with quality to the surrounding crowdsourcing user stations through the C2C link.

[0178] The application further discloses a computer readable storage medium which stores a computer program, and the computer program is executed by a processor to realize the PPP-RTK positioning service method based on the crowdsourcing mode.

[0179] The application further discloses a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the PPP-RTK positioning service method based on the crowdsourcing mode when executing the computer program.

[0180] The application is described according to flowcharts and / or block diagrams of the method, device (system), and computer program product of the specific embodiments. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be realized by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device for realizing the functions specified in the flows and / or blocks in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus for realizing the functions specified in one or more flows and / or blocks.

[0181] These computer program instructions can also be stored in a computer-readable memory capable of guiding the computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product comprising instruction apparatus, which realizes the functions specified in the flows and / or blocks in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus for realizing the functions specified in one or more flows and / or blocks.

[0182] These computer program instructions can also be loaded into a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide a process for realizing the functions specified in the flows and / or blocks in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus for realizing the functions specified in one or more flows and / or blocks.

[0183] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it. For those skilled in the art, the technical solutions recorded in the above embodiments can be modified, or some technical features can be replaced by equivalents; and all these modifications and replacements shall belong to the protection scope of the present application.

Claims

1. A PPP-RTK positioning service method based on a crowdsourcing model, characterized in that, The PPP-RTK positioning service method includes: Obtain the approximate location of the initial user station and the first satellite products broadcast by the service center, and generate the first raw observation data based on satellite signal observations from GNSS; A first observation equation is established, and the first observation equation is iteratively solved based on the non-ionospheric combination of the first original observation data and the first satellite product to obtain the solution location of the initial user station and report it to the service center to register it as a crowdsourced user station. The initial user station's solution location, the first original observation data, and the first satellite product are inverted to obtain initial user corrections, including tropospheric corrections, pseudorange corrections, and phase ionospheric corrections. The initial user corrections that have passed the verification and been quality-marked are then broadcast to surrounding crowdsourced user stations via a C2C link. The approximate location of the crowdsourced user station, the multi-source user correction data broadcast by the surrounding reference user stations, the second satellite product broadcast by the service center and the calculated location of the reference user station are obtained, and second raw observation data are generated based on satellite signal observations from GNSS. The location coordinate difference between the crowdsourcing user station and the reference user station is obtained, and the received multi-source user correction number is interpolated by combining the number of surrounding reference user stations. The interpolated multi-source user correction number is then used to correct the second original observation data. A differentiated second observation equation is established based on the multi-source user corrections with different quality labels. The second observation equation is then iteratively solved based on the corrected second original observation data and the second satellite product to obtain the solution location of the crowdsourced user station and report it to the service center. Based on the solution location of the crowdsourcing user station, the second original observation data, and the second satellite product, the interpolated multi-source user correction number is corrected and inverted to obtain the user enhancement correction number of the crowdsourcing user station. The user enhancement correction number that has passed the verification and been quality-marked is broadcast to the surrounding crowdsourcing user stations through the C2C link. The establishment of the first observation equation, which involves iteratively solving the first observation equation based on the ionospheric combination of the first original observation data and the first satellite product, includes: Establish the first set of observation equations, the functional expression of which is: In the formula, For satellite identification, It is an ionosphere-free assemblage. The speed of light in a vacuum. These are pseudorange observations from satellites without ionospheric assemblies. For the clock bias of satellites without ionospheric assemblies, Calculate the satellite distance to the ground for the user's location. For the clock bias of the user receiver without ionosphere, This is the constant deviation of the initial user station receiver simultaneously receiving signals from different navigation systems. For oblique tropospheric delay, For pseudorange observation noise of satellites without ionospheric assemblies, The equivalent wavelength for an ionosphere-free combination. These are phase observations of the satellite without an ionospheric array. For floating-point ambiguity of satellite-based ionospheric combined phase observations, Phase observation noise for satellites without ionospheric assemblies; The first raw observation data is transformed into ionospherically-free combined observations, and orbit and clock error products and UPD products are extracted from the first satellite products. Substitute the ionosphere-free combined observations, the orbit and clock error products into the first observation equation, and perform multi-epoch iterative calculations on the first observation equation based on the filtering algorithm to gradually converge and solve for the initial user station's solution position, receiver clock error, and floating-point ambiguity. The extracted UPD product is used to fix the calculated floating-point ambiguity into an integer ambiguity. The first observation equation is then recalculated based on the integer ambiguity to obtain the optimal solution position of the initial user station.

2. The PPP-RTK positioning service method based on crowdsourcing model according to claim 1, characterized in that, The PPP-RTK positioning service method further includes, after calculating the initial user station's location, inverting the calculation to obtain the initial user correction number and performing verification marking, including: Establish a set of inversion equations for the initial user corrections, the functional expression of which is: In the formula, This is the tropospheric delay correction for the initial user station's calculated location. Let i be the pseudorange ionospheric delay correction at the i-th frequency point of the initial user station's calculated location. This represents the original pseudorange observation value of the satellite at the i-th frequency point. Let i be the phase ionospheric delay correction at the i-th frequency point of the initial user station's calculated location. Let be the wavelength of the electromagnetic wave at the i-th frequency point. The original ambiguity of the satellite at the i-th frequency point. The original phase observation value of the satellite at the i-th frequency point. It serves as an identifier for the signal frequency; The initial user station's solution location, floating-point ambiguity, receiver clock error, and the first original observation data are substituted into the inversion equation to calculate the initial user correction, which includes tropospheric correction, pseudorange, and phase ionospheric correction. Based on the satellite-to-ground distance deviation between the calculated and actual positions of the initial user stations, an error propagation model is established to represent the propagation of this deviation in the initial user station corrections. The functional expression of the error propagation model is as follows: In the formula, This is the tropospheric delay correction for the initial actual location of the user station. This is the pseudorange ionospheric delay correction at the i-th frequency point of the initial user station's true location. For the deviation of the satellite distance, The satellite distance to the ground is the actual location of the user station. Phase ionospheric delay correction at the i-th frequency point of the initial user station's actual location; The influence of the satellite-to-ground distance deviation in the error propagation model on the initial user correction is evaluated. Based on the evaluation results, the initial user correction is quality checked. Based on the check results, a first-class quality label is generated for the initial user correction that passes the quality check, and a second-class quality label with a quality level lower than the first-class quality label is generated.

3. The PPP-RTK positioning service method based on crowdsourcing model according to claim 2, characterized in that, The step of obtaining the location coordinate difference between the crowdsourced user station and the reference user station, and interpolating the received multi-source user correction data based on the number of surrounding reference user stations, includes: Based on the approximate location of the crowdsourced user station and the calculated location of the reference user station broadcast by the service center, the position coordinate difference between the crowdsourced user station and the reference user station is calculated. The reference user station includes the initial user station, other crowdsourced user stations, and existing CORS reference user stations. A corresponding low-order surface interpolation model is established based on the number of surrounding reference user stations. The function expression of the low-order surface interpolation model is as follows: In the formula, For satellite identification, This is a general location for crowdsourcing user sites. This is the ionospheric delay correction number interpolated based on the approximate location of the crowdsourced user site. This is the tropospheric delay correction value interpolated based on the approximate location of the crowdsourced user site. , , , The coefficients are those of the low-order surface interpolation model. The difference in coordinates between the crowdsourcing user station and the reference user station along the X-axis. The difference in coordinates between the crowdsourcing user station and the reference user station along the Y-axis. The elevation difference between the crowdsourcing user station and the reference user station. The number of reference user stations broadcasting in the surrounding area; By performing least squares fitting on the position coordinate difference and the multi-source user correction, the coefficients in the corresponding low-order surface interpolation model are determined. Substituting the position coordinate difference into the low-order surface interpolation model after determining the coefficients, the interpolated multi-source user correction number is obtained.

4. The PPP-RTK positioning service method based on crowdsourcing model according to claim 3, characterized in that, The step of correcting the second original observation data using the interpolated multi-source user corrections includes: Establish a set of corrected equations for the original observation data. The functional expression of the set of corrected equations is as follows: In the formula, This is the original pseudorange observation value corrected by the satellite at the i-th frequency point. This represents the original pseudorange observation value of the satellite before correction at the i-th frequency point. This is the pseudorange ionospheric delay correction at the i-th frequency point after interpolation based on the approximate location of the crowdsourced user station. The speed of light in a vacuum. For satellite clock bias, Let be the wavelength of the electromagnetic wave at the i-th frequency point. This is the original phase observation value of the satellite at the i-th frequency point after correction. The original phase observation value of the satellite before correction at the i-th frequency point. This is the phase ionospheric delay correction at the i-th frequency point after interpolation based on the approximate location of the crowdsourced user station; Substituting the interpolated multi-source user corrections into the correction equations yields the corrected second original observation data.

5. The PPP-RTK positioning service method based on crowdsourcing model according to claim 4, characterized in that, The PPP-RTK positioning service method further includes calculating the solution location of the crowdsourced user station after correcting the second original observation data, including: If the multi-source user corrections carry a first-type quality label, a second observation equation is established, and the functional expression of the second observation equation is: If the multi-source user corrections carry a second type of quality label, establish the second observation equation, the functional expression of which is: In the formula, Calculate the satellite distance to the ground for the user's location. For the clock bias of the receiver at the crowdsourcing user station, Let be the frequency-dependent ionospheric delay coefficient at the i-th frequency point. To determine the oblique ionospheric delay based on the approximate location of the crowdsourcing user station, This is the projection function of the tropospheric delay mapping from the zenith direction to the satellite's oblique path direction. For the satellite elevation angle, For tropospheric delay in the zenith direction, The pseudorange observation noise of the satellite at the i-th frequency point, The phase observation noise of the satellite at the i-th frequency point, Let be the floating-point ambiguity of the phase observation of the satellite at the i-th frequency point; The orbit and clock bias products and UPD products are extracted from the second satellite products. Based on the quality marker of the multi-source user correction, the corrected second original observation data and the orbit and clock bias products are substituted into the corresponding second observation equation. The second observation equation is then subjected to multi-epoch iterative calculation based on the filtering algorithm to gradually converge and solve the solution position, receiver clock bias and floating-point ambiguity of the crowdsourced user station. The extracted UPD product is used to fix the calculated floating-point ambiguity into an integer ambiguity. The second observation equation is then recalculated based on the integer ambiguity to obtain the optimal solution position of the crowdsourcing user station.

6. The PPP-RTK positioning service method based on crowdsourcing model according to claim 5, characterized in that, The PPP-RTK positioning service method further includes, after calculating the calculated location of the crowdsourced user station, correcting and inverting the interpolated multi-source user correction number to obtain the user enhancement correction number of the crowdsourced user station and performing verification marking, including: Based on the interpolated tropospheric delay correction, the residual error of the tropospheric delay during the calculation of the crowdsourced user station's location is added to obtain the tropospheric enhancement delay correction for the crowdsourced user station. The calculation function expression for the tropospheric enhancement delay correction is as follows: In the formula, Calculate the tropospheric enhancement delay correction for the location of crowdsourced user stations; A sliding time window is used to smooth the tropospheric enhancement delay correction over multiple epochs. The function expression for the smoothing is as follows: In the formula, To smooth out the tropospheric delay, For the index of the target epoch, This indicates the number of epochs taken before and after the target epoch within the time window. Indicates an index for any epoch; Based on the solution location of the crowdsourced user station, receiver clock error, floating-point ambiguity, and the corrected second original observation data, the ionospheric correction value at the solution location of the crowdsourced user station is obtained by combining the smoothed tropospheric delay inversion calculation. The calculation function expression for the ionospheric correction value is as follows: In the formula, To calculate the pseudorange ionospheric correction value at the location of the crowdsourced user station. For the clock bias of satellites without ionospheric assemblies, For the clock bias of the user receiver without ionosphere, Calculate the phase ionospheric correction value at the location of the crowdsourcing user station; The interpolated ionospheric delay correction is corrected using the ionospheric correction value to obtain the ionospheric enhancement delay correction for the crowdsourcing user station. The calculation function expression for the ionospheric enhancement delay correction is as follows: In the formula, The pseudorange tropospheric enhancement delay correction is calculated for the location of crowdsourced user stations. This is the pseudorange ionospheric delay correction number interpolated at the i-th frequency point based on the approximate location of the crowdsourced user station. The phase tropospheric enhancement delay correction for the location of the crowdsourced user station is calculated. This is the phase ionospheric delay correction number interpolated at the i-th frequency point based on the approximate location of the crowdsourced user station; The user enhancement corrections are subjected to quality inspection, and the first type of quality label and the second type of quality label are generated for the user enhancement corrections that pass the quality inspection based on the inspection results.

7. The PPP-RTK positioning service method based on crowdsourcing model according to claim 1, characterized in that, The PPP-RTK positioning service method also includes data communication between the user and surrounding users, including: The approximate location of the initial user station is sent to the service center, and the service center broadcasts satellite products and a list of nearby services registered as crowdsourcing user stations to the receiver of the initial user station based on the approximate location. The service list includes the solution location and IP address of the crowdsourcing user station. Based on the service list returned by the service center, the initial user station selects a group of nearby crowdsourcing user stations and sends a data request. In response to the data request from the initial user station, the requested crowdsourcing user station generates enhanced information, including atmospheric delay corrections, in real time and sends it back to the initial user station via a C2C link. The location of the initial user station is calculated based on the satellite products broadcast by the service center and the augmented information returned by the requested crowdsourced user station. Once the location of the initial user station is calculated and converged stably, the calculated location and IP address of the initial user station are reported to the service center to register it as a crowdsourcing user station.

8. A location service system, employing the PPP-RTK location service method based on a crowdsourcing model as described in any one of claims 1-7, characterized in that, The location service system includes: The satellite information broadcasting module is used to obtain the approximate location of the initial user station and the first satellite products broadcast by the service center, and to generate the first raw observation data based on satellite signal observations from GNSS. The initial user station location calculation module is used to establish a first observation equation, and iteratively solve the first observation equation based on the non-ionospheric combination of the first original observation data and the first satellite product to obtain the calculated location of the initial user station and report it to the service center for registration as a crowdsourced user station. The initial user correction generation module is used to perform inversion calculations on the solution location of the initial user station, the first original observation data and the first satellite product to obtain initial user corrections including tropospheric corrections, pseudorange and phase ionospheric corrections. The initial user corrections that have passed the verification and been quality marked are broadcast to the surrounding crowdsourced user stations through the C2C link. The satellite and user information broadcasting module is used to obtain the approximate location of the crowdsourced user station, the multi-source user correction numbers broadcast by the surrounding reference user stations, the second satellite product broadcast by the service center and the calculated location of the reference user station, and generate second raw observation data based on satellite signal observations from GNSS. The observation data correction module is used to obtain the position coordinate difference between the crowdsourcing user station and the reference user station, interpolate the received multi-source user correction number in combination with the number of surrounding reference user stations, and use the interpolated multi-source user correction number to correct the second original observation data. The crowdsourced user station location calculation module is used to establish a differentiated second observation equation based on the multi-source user corrections with different quality labels, and to iteratively solve the second observation equation based on the corrected second original observation data and the second satellite product to obtain the calculated location of the crowdsourced user station and report it to the service center. The crowdsourced user station correction number generation module is used to correct and invert the interpolated multi-source user correction number based on the solution location of the crowdsourced user station, the second original observation data and the second satellite product to obtain the user enhancement correction number of the crowdsourced user station, and broadcast the user enhancement correction number that has passed the verification and been quality marked to the surrounding crowdsourced user stations through the C2C link.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the PPP-RTK location service method based on the crowdsourcing model as described in any one of claims 1-7.

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