199 results about "Precise Point Positioning" patented technology

The invention relates to the technical field of inertial assistance, in particular to a Beidou high-precision space-time reference dynamic compensation system based on inertial assistance, which is characterized in that an inertial measurement unit module is used for measuring original measurement data, and the original measurement data comprises a carrier phase and a Doppler observation value; the processing unit module is used for fusing the inertial measurement unit, executing real-time environment perception and dynamic modeling, classifying an operation environment and predicting error characteristics; performing an adaptive robust fusion filtering algorithm that dynamically adjusts filter parameters and switches a filter model to estimate the position and attitude of the carrier; and in combination with radio wave precision single-point positioning enhancement service, super-tight combination signal tracking and integrity monitoring are realized, an estimated inertial assistance system state is fed back to a tracking loop of the multi-frequency Beidou receiving module, and real-time fault detection is performed on original measurement data.

The invention provides a GNSS virtual observation value generation method and system based on real-time precise point positioning, and belongs to the technical field of GNSS positioning, and the method comprises the steps: obtaining ephemeris clock error data and observation data received by a reference station in real time, filling a UCUD PPP observation equation, and solving a non-difference floating point solution of a to-be-estimated parameter of each parameter station; through UPD estimation, non-difference floating point solution ambiguity parameters recover the whole cycle characteristic, and a fixed solution STEC and a fixed solution ZTD are obtained; the STEC is locally fitted into a function about the position, and a regional non-difference ionosphere model is established; the ZTD is locally fitted into a function about the position, and a regional non-difference troposphere model is established; and generating a double-difference atmospheric delay between the main reference station and the virtual reference station based on the non-difference ionosphere model and the regional non-difference troposphere model to obtain a virtual observation value. According to the method, the reliability of GNSS signal atmospheric delay is effectively improved, so that the quality of a virtual observation value is improved.

The invention discloses a multi-frequency multi-mode signal multi-path error weakening method, and relates to the technical field of precision positioning, and the method comprises the steps: constructing a multi-frequency multi-mode non-combination precision single-point positioning observation equation, separating multi-path errors in pseudo-range and phase observation values through the equation, and forming residual data; performing quality control on the residual error, and eliminating an abnormal value; feature extraction and judgment are carried out based on residual data, wherein time repeatability features, spatial distribution features and trend complexity features are extracted; selecting a correction model according to a feature judgment result, wherein the correction model comprises a fixed star daily filtering model, a multi-path hemispherical graph model and a trend surface analysis multi-path hemispherical graph model; and generating a multi-path error correction amount through a selected model, correcting an original observation value, and outputting a positioning result. The method solves the problem that the positioning precision is reduced due to multi-path errors, can effectively weaken the multi-path errors, improves the positioning precision and stability, adapts to a complex environment, and reduces data processing redundancy.

The invention belongs to the technical field of time service, and relates to a Beidou time service delay processing method and device based on PPP-B2b. The method comprises the following steps: acquiring a navigation signal of a current epoch to obtain an observation value, a broadcast ephemeris and precise point positioning service information; obtaining a precision satellite position and a precision satellite clock error according to the broadcast ephemeris and the precision single-point positioning service information; forecasting to obtain a forecast value; calculating a difference value between the forecast value and the observation value, when the difference value does not exceed a preset threshold value, establishing a satellite pseudo-range and carrier phase ionosphere-free combination observation equation, establishing an antenna position constraint virtual observation equation, and performing resolving according to the combination observation equation and the virtual observation equation to obtain a receiver clock error result; and correcting the pulse per second according to a clock error result of the receiver so as to carry out delay time service. According to the invention, accurate time service can be realized, interference and environmental influence are avoided, and the convergence speed is high.

The invention relates to the technical field of GNSS (Global Navigation Satellite System) navigation and positioning, in particular to a GNSS real-time precise single-point positioning ambiguity fixing method for a complex environment. The method comprises the steps of obtaining and processing data, obtaining a precision satellite orbit and a precision satellite clock error from original observation data, broadcast ephemeris and an SSR correction number which are originally obtained in sequence, obtaining original frequency point non-difference floating point ambiguity, obtaining fixed integer inter-satellite single-difference wide-lane ambiguity, and obtaining floating point inter-satellite single-difference narrow-lane ambiguity. And finally, selecting the complete set ambiguity according to the precision index of the floating point narrow lane ambiguity, and carrying out iteration to obtain an ambiguity subset meeting the optimal aperture check rule. Through the method, the ambiguity fixing reliability can be further improved, and the convergence time is shortened.

A Beidou / GNSS-based real-time high-precision sea surface measurement method and a buoy, wherein by using free-to-use broadcast ephemeris freely broadcast by GNSS satellites, precise point positioning of China's Beidou satellites, and other high-precision service space signals, real-time centimeter-level element information comprising time, longitude, latitude, water level, wave height, wave period, wave direction, sea surface current velocity and direction, atmospheric water vapor content, and the like can be directly obtained. The information can be stored locally in a buoy or transmitted back by communication, and is suitable for real-time high-precision sea surface measurements in offshore and far-sea scenarios.

The invention relates to the technical field of satellite navigation and positioning, and discloses a Beidou precise point positioning method based on double-frequency combination, which comprises the following steps of: firstly, acquiring an original observation file and various correction files of a double-frequency signal from an IGS official website; a clean observation value is obtained through the steps of data validity checking and data preprocessing; carrying out correction and correction to obtain an error correction value; establishing a Beidou dual-frequency ionospheric elimination combination model, and performing dual-frequency DCB correction on the combination observation value to obtain a corrected dual-frequency combination observation value; constructing a double-frequency ionosphere elimination observation equation, and performing coordinate solution by using Kalman filtering to obtain a positioning result of double-frequency combination; analyzing the positioning result of the double-frequency combination, counting the error value of the positioning result, and evaluating the positioning precision and the convergence time; according to the invention, when DCB correction is considered, a dual-frequency ionosphere-eliminating PPP positioning model is established by using a BDS signal, so that the positioning precision can be remarkably improved, and the convergence time can be shortened.

The embodiment of the invention discloses a precision positioning acceleration method and device based on a low earth orbit satellite / LSTM neural network. The method comprises the steps that a terminal obtains a wide lane phase decimal deviation product, a narrow lane phase decimal deviation product and a first GNSS combination observation value which are generated by a server based on an LSTM method and are subjected to coding processing; determining a first GNSS wide lane real number ambiguity according to the first GNSS wide lane real number Based on a precise point positioning algorithm, determining initial GNSS ionosphere elimination combination real ambiguity and other parameters; performing inter-satellite single difference on the first GNSS wide-lane real number ambiguity, and obtaining the integer ambiguity by combining wide-lane phase decimal deviation product fixation; performing inter-satellite single difference on the initial GNSS ionosphere-free combination real ambiguity, determining a first GNSS narrow-lane real ambiguity by combining the wide-lane integer ambiguity, and fixing the first GNSS narrow-lane real ambiguity by using a narrow-lane phase decimal deviation product through a partial ambiguity fixing method to obtain the integer ambiguity of the narrow-lane phase decimal deviation product; and calculating a user coordinate fixed solution in combination with related parameters.

The invention discloses a self-adaptive positioning method and device, equipment and a storage medium, and relates to the technical field of unmanned equipment. According to the technical scheme provided by the invention, the method comprises the steps: determining the convergence condition of a precise point positioning mode according to the task precision of mobile equipment and / or the convergence speed of the precise point positioning mode; after a positioning system of the mobile equipment is powered on, first position information of the mobile equipment is solved in a self-differential positioning mode, and second position information of the mobile equipment is solved in a precise single-point positioning mode; under the condition that the second position information does not meet the convergence condition, determining that the first position information is target position information of the mobile equipment; and under the condition that the second position information meets the convergence condition, determining target position information of the mobile equipment based on the second position information. Through the technical means, the convergence efficiency and the convergence precision of the positioning system can be balanced by adjusting the convergence condition, so that the operation precision of the mobile equipment is improved.

The invention provides an elastic non-difference and non-combination-based PPP-RTK high-precision positioning method and device, and belongs to the field of satellite navigation high-precision positioning, and the method comprises the steps: obtaining reference station data, and judging the validity of the reference station data; if the reference station data is valid, outputting satellite navigation positioning information based on a real-time dynamic positioning technology RTK; and if the reference station data is invalid, acquiring enhanced data of a non-difference and non-combination positioning technology PPP-RTK, and outputting satellite navigation positioning information based on a precision single point positioning technology PPP, a precision single point positioning ambiguity estimation technology PPP-AR or a PPP-RTK technology according to the PPP-RTK enhanced data, a preset positioning precision requirement and a resource occupation condition of the terminal equipment. According to the invention, by judging the validity of the reference station data and dynamically adjusting the positioning mode, the influence of the change of the environment where the terminal equipment is located on the reference station data is avoided, the precision of the positioning result can be always kept at a relatively high level, and a better high-precision positioning service result is obtained.

The invention discloses a global ionosphere modeling method and device based on Beidou single-frequency ionosphere weighted PPP, and belongs to the technical field of GNSS navigation positioning and atmosphere modeling. The method comprises the following steps: acquiring real-time precise orbit and clock error information of a Beidou satellite and an initial ionospheric delay correction value; a single-frequency ionosphere weighted precision single point positioning (SF-IW-PPP) observation equation is constructed; establishing a space-time correlation constraint model of the ionized layer delay error and determining a prior variance; carrying out combined calculation by taking the previous variance as a constraint to obtain an ionosphere delay residual error, and further obtaining the total delay of the high-precision inclined ionosphere; and finally generating a global ionosphere grid model. According to the invention, high-precision and real-time global ionosphere modeling is realized by only needing a low-cost single-frequency receiver and combining Beidou real-time enhancement service, the hardware threshold and data processing delay are remarkably reduced, and the method is suitable for the fields of public navigation, intelligent transportation, space weather monitoring and the like.

The invention provides a precise point positioning method and system based on broadcast ephemeris satellite clock speed forecast, and the method comprises the steps: collecting broadcast ephemeris clock speed data, and filtering the broadcast ephemeris clock speed data through a dynamic sliding window; preprocessing the filtered broadcast ephemeris clock speed data, and removing abnormal state data to obtain preprocessed broadcast ephemeris clock speed data; fitting the preprocessed broadcast ephemeris clock speed data by adopting a linear period combination model and utilizing a least square method to obtain a fitted clock speed model of each satellite, and obtaining a satellite clock speed predicted value based on the fitted clock speed model; according to the satellite clock speed predicted value, user information and satellite information are combined, user equivalent distance measurement errors of a satellite orbit and clock error jump when broadcast ephemeris of each satellite is updated are calculated, the user equivalent distance measurement errors are applied to precise single-point positioning data for calculation and adjustment, and a corrected precise single-point positioning result is obtained.

The invention relates to the technical field of navigation and positioning, in particular to a PPP / INS / laser radar combined positioning method and system based on graph optimization. Constructing a to-be-optimized factor graph by taking the IMU pre-integral measurement value, the variation of the laser radar inertial odometer and the precise single-point positioning as factor nodes, and acquiring the initial pose of the motion carrier by using the IMU original observation data, the IMU odometer and the laser radar inertial odometer; and judging the signal quality of a global navigation satellite system (GNSS) by using a specified index, selecting a laser radar inertial odometer-based factor or combining precise point positioning and a laser radar inertial odometer according to the signal quality of the GNSS to carry out optimization solution on the factor graph, so as to obtain the pose of the motion carrier according to an optimization solution result. According to the method, accurate and robust estimation of global positioning can be realized, and continuous and accurate positioning of a carrier in each application scene can be realized.

The invention relates to the field of marine meteorological monitoring, and discloses a GNSS-based marine troposphere atmosphere rainfall real-time monitoring method, which comprises the following steps: estimating total troposphere zenith delay of an observation station position by using GNSS precise point positioning, and calculating troposphere zenith dry delay by using meteorological elements so as to obtain troposphere zenith wet delay; obtaining ERA5 reanalysis data, and constructing an atmospheric weighted average temperature model; calculating an atmospheric weighted average temperature and a water vapor conversion coefficient by using an atmospheric weighted average temperature model and combining with meteorological elements of the observation station position; and calculating atmospheric rainfall of the troposphere by using the troposphere zenith wet delay and the water-vapor conversion coefficient at the observation station position. According to the method disclosed by the invention, the GNSS signal which is high in space-time coverage and passively received is taken as a signal source, real-time precise single-point positioning is carried out, zenith troposphere wet delay is extracted, and atmospheric rainfall can be monitored in real time in a high-precision manner under the condition of lacking historical sounding data.

The invention discloses a Galileo HAS service receiving and positioning performance evaluation method and device, and belongs to the technical field of satellite positioning and navigation. The method comprises the steps that Galileo E6B frequency band signals are captured through USRP equipment, after radio frequency and direct current signals are separated through a bias device, self-adaptive layering processing is carried out through GNSS-SDR software, and the self-adaptive layering processing comprises dynamic sampling and interference suppression of a radio frequency adaptation layer, double-domain cooperative synchronization and self-adaptive decoding of a baseband intelligent processing layer and self-adaptive decoding of a baseband intelligent processing layer. And carrying out multi-dimensional feature mapping and robust verification on the HAS correction number extraction layer, and finally outputting a standardized HAS correction number. And in combination with a real-time precise single-point positioning technology, centimeter-level dynamic positioning is realized, and the positioning performance is evaluated through comparison with reference station data. According to the method, the robustness and precision of signal receiving and processing are improved, and the method is suitable for high-precision positioning requirements in a complex environment.

The invention relates to the technical field of computers, and particularly provides a time service method and device of a low-orbit satellite, electronic equipment and a storage medium. The method comprises the following steps: acquiring a digital navigation signal, and suppressing an interference spectral line of the digital navigation signal to obtain a suppressed digital navigation signal; performing amplitude-frequency compensation on the suppressed digital navigation signal to obtain a target navigation signal; correcting the pseudo-range observation model and the carrier phase observation model of the low-orbit satellite based on an error model of precise point positioning to obtain a corrected pseudo-range observation model and a corrected carrier phase observation model; and carrying out precise point positioning calculation on the corrected pseudo-range observation model, the corrected carrier phase observation model and the navigation message of the target navigation signal to obtain clock error data of the target navigation signal, and carrying out time service on a local clock according to the clock error data.

The invention relates to the technical field of positioning. The deep learning assisted satellite positioning rapid resolving method comprises the following steps: acquiring and preprocessing satellite observation data, local environment characteristic data and receiver state data to generate multi-source fusion input data; performing dynamic error prediction processing through a locally deployed deep learning model to generate a positioning error correction amount; the positioning error correction is fused to a precise single-point positioning calculation process for iterative optimization processing, and positioning coordinates meeting the requirement for regional surveying and mapping precision are generated; a local historical observation data set is combined to trigger an online learning mechanism to perform model parameter updating processing, and a self-adaptive optimization model is generated so as to dynamically adapt to ionosphere / troposphere disturbance in a local complex environment, improve the resolving convergence efficiency in a multi-path effect scene and improve the real-time performance of the multi-path effect scene. And through multi-source data coupling modeling, the technical effects of error correction and accurate adaptation of a real scene are realized.

The invention provides a navigation satellite short-term clock error forecasting method considering forecasting residual error periods, and relates to the technical field of satellite navigation. The method comprises the following steps: acquiring satellite real-time clock error data, and determining a modeling time window length and a forecast time length; performing epoch-by-epoch real-time sliding forecast on the satellite clock error by using a linear model, and subtracting the forecast clock error from the real-time clock error to obtain an error sequence; performing spectral analysis on the error sequence, and identifying main periodic terms; setting a scaling parameter related to the forecast time length, and establishing a periodic model in combination with the main periodic term fitting error sequence; in the subsequent sliding forecasting, the linear model is used for forecasting the clock error main trend, meanwhile, the periodic model is used for forecasting the residual periodic error, and the two results are added to obtain a final forecasting value. According to the method, by capturing the periodic error in the clock error, the short-term clock error forecasting precision is remarkably improved, the problems of real-time clock error service delay and data loss can be solved, and support is provided for real-time precise single-point positioning.

The invention provides a method and a device for acquiring state parameters of high-orbit and low-orbit constellation joint precision point positioning, and relates to the technical field of satellite navigation. Obtaining observation data based on high and low orbit combined satellite constellation parameters, receiver position parameters and epoch moments; preprocessing the observation data to obtain target observation data generated after preprocessing, and carrying out high and low orbit constellation joint standard single-point positioning solution based on the target observation data to obtain a single-point positioning solution; and performing state estimation and ambiguity fixation by taking the single-point positioning solution as an iterative initial value of Kalman filtering to obtain state parameters.

The invention discloses a mobile behavior interference method and device, mobile equipment and a storage medium, and relates to the technical field of unmanned equipment. According to the technical scheme, the method comprises the steps that after a positioning system of the mobile equipment is powered on, first position information of the mobile equipment is solved in a self-differential positioning mode, and second position information of the mobile equipment is solved in a precise single-point positioning mode; under the condition that the second position information is not calculated, determining that the first position information is target position information of the mobile equipment, and determining an actual convergence speed of a precise point positioning mode; comparing the actual convergence speed with the expected convergence speed; and under the condition that the actual convergence speed is smaller than the expected convergence speed, interfering with the moving behavior of the mobile equipment. Through the technical means, when the speed or the position of the mobile equipment affects the resolving efficiency of the precise single-point positioning mode, the moving behavior of the mobile equipment is interfered so as to lower the moving speed of the mobile equipment or move the mobile equipment out of the shielding area, and the resolving efficiency is improved.

The invention provides a railway user terminal adaptive positioning method and system, and relates to the technical field of wireless communication networks, and the method comprises the steps: determining that a target railway user terminal currently accesses a railway Beidou application service platform through terminal account login; if yes, a real-time positioning service based on a target positioning mode corresponding to the positioning precision requirement type is provided for the terminal according to the positioning precision requirement type of the terminal so as to send real-time positioning data to the terminal, and the target positioning mode comprises a precision single-point positioning and real-time dynamic positioning mode or a real-time dynamic differential positioning mode; and providing a corresponding real-time reference conversion service for the terminal according to the reference conversion demand type of the terminal so as to send real-time reference conversion data to the terminal, so that the terminal corrects the real-time positioning data according to the real-time reference conversion data. According to the invention, a high-precision self-adaptive elastic positioning service can be provided for the railway user terminal, so that the positioning precision, the dynamic adaptability, the reliability and the effectiveness of the railway user terminal can be effectively improved.

A precision measurement and tamping operation method for an operating conventional-speed railway without a control network. The method comprises the following steps: S100, laying a temporary reference station (1) and performing initial precision track measurement; S200, processing office-processed data; and S300, performing tamping operation and precision measurement. The temporary reference station (1) is laid offline along an operation route by means of precise single-point positioning; when precision track measurement is performed by using a track inspector (2), the temporary reference station (1) may serve as a reference station and cooperate with an onboard moving station (3) to perform dynamic post-processing calculation, such that accurate coordinates of the center line of the route are obtained; and when precision tamping is performed by using a tamping vehicle (4) equipped with a tamping vehicle locator (5), the temporary reference station (1) may serve as a main reference station to provide real-time dynamic positioning for the tamping vehicle (4), thereby realizing centimeter-level mileage positioning accuracy, and realizing autonomous synchronization with field mileage.

The invention provides a troposphere delay correction method and system, electronic equipment and a storage medium, and the method comprises the steps: extracting troposphere delay of a reference station through a non-difference combination observation value method according to the obtained real-time reference station observation data, broadcast ephemeris, ultra-fast orbit and clock correction, carrying out the adjustment of observation values of a plurality of satellites, and carrying out the adjustment of the observation values of a plurality of satellites; the zenith troposphere delay of the base station is obtained; the zenith troposphere level of the base station after normalization processing is interpolated to the position of the moving station through an inverse distance weighted interpolation method, zenith troposphere delay of the moving station is obtained according to a pre-constructed elevation normalization model, and the elevation normalization model is constructed based on ERA5 horizontal atmospheric layer meteorological data. According to the method, the adaptability of the model to complex terrains can be improved, so that the model precision is improved, the precision single-point positioning convergence time of the moving station is effectively shortened, and the precision single-point positioning precision is improved.

The invention discloses an orbit determination method and device for a low-orbit satellite, the low-orbit satellite and a storage medium, and the method comprises the steps: obtaining global navigation satellite system (GNSS) observation data and broadcast ephemeris received by a receiver in the low-orbit satellite, and obtaining orbit state information in a PPP-B2b signal broadcasted by a Beidou No.3 system; preprocessing the GNSS observation data according to an observation model based on the GNSS observation data to obtain preprocessed GNSS observation data, and determining first position information of a GNSS satellite according to the broadcast ephemeris and the orbit state information; and determining orbit position information of the low-orbit satellite according to the preprocessed GNSS observation data and the first position information. Therefore, the low-orbit satellite can complete high-precision orbit positioning under the condition of limited computing power.

The invention discloses a Beidou four-frequency precise point positioning method and system based on satellite-based enhancement service. The method comprises the following steps: receiving and decoding a Beidou four-frequency signal, a PPP-B2b signal and a broadcast ephemeris in real time; the correction information in the PPP-B2b signal is matched with the corresponding information in the broadcast ephemeris; applying the orbit correction information to a broadcast ephemeris orbit; applying the clock error correction information to the broadcast ephemeris clock error; a Beidou four-frequency ionosphere-free dual-combination positioning model is constructed; correcting orbits and clock error parameters of the model; unifying the receiver end clock error in the ionosphere-free combination observation equation of B1C / B2a, and linearizing the corrected model; and resolving the Beidou four-frequency ionosphere-free dual-combination positioning model to obtain a high-precision receiver position coordinate. According to the invention, the problems of low positioning precision and slow convergence speed in dual-frequency PPP-B2b positioning can be solved.

The invention relates to an unmanned aerial vehicle high-precision positioning method based on micro-centimeter space low-orbit constellation and Beidou PPP-B2b fusion enhancement, and the method comprises the steps: obtaining a precise orbit correction number and a precise clock correction number of a GPS and a BDS system based on a Beidou PPP-B2b signal; calculating a precise orbit and a precise clock error of the GNSS satellite based on the precise orbit correction and the precise clock error correction; on the basis of the precise orbit and the precise clock error of the GNSS satellite, an observation value of a micro-centispace low-orbit satellite is fused, and a GNSS / LEO combined PPP observation model is constructed; and based on extended Kalman filtering, precise point positioning calculation is carried out on the GNSS / LEO combined PPP observation model, and the real-time high-precision position of the unmanned aerial vehicle is obtained. According to the invention, the real-time high-precision position of the unmanned aerial vehicle can be rapidly and stably obtained, and a reliable position reference is provided for autonomous operation of the unmanned aerial vehicle in a network-free environment.

The invention provides a high-precision precise point positioning method based on BDS-3, and relates to the technical field of wireless communication. The method comprises the following steps: firstly, introducing a traditional ionosphere-free combination model to eliminate the influence of ionosphere delay on positioning precision, and eliminating or weakening a satellite orbit error and a clock error error by using satellite orbit and clock error data provided by an IGS; secondly, constructing a troposphere correction model of adaptive weighted wet delay for eliminating troposphere delay errors; thirdly, establishing a self-adaptive random model, and reasonably weighting pseudo-range and carrier phase observed quantity; and finally, estimating the parameters to be estimated through extended Kalman filtering so as to obtain a positioning calculation result. The method has obvious advantages in the aspect of improving the positioning precision, can meet the requirement of high-precision positioning, can realize centimeter-level positioning precision no matter in a dynamic mode or a static mode, and can even reach millimeter-level positioning precision in the static mode in some observation stations and directions.

The invention discloses a stability analysis method and system for a BDS / GNSS reference station of a dam slope. The invention discloses a method for analyzing stability of GNSS reference stations in a dam and a surrounding area by using a GNSS station coordinate time sequence, and belongs to the field of GNSS precision positioning and engineering monitoring interdiscipline. According to the method, stable GNSS reference stations in a reservoir area and around the reservoir area are selected, long-term observation data are processed through a precise point positioning (PPP) mode with fixed ambiguity, and a high-precision GNSS station coordinate time sequence is obtained. Then, through the steps of reference frame alignment, data preprocessing, environmental load and thermoelastic deformation elimination and the like, non-structural signal interference is eliminated, and a clean coordinate time sequence is obtained. On the basis, parameter estimation is carried out by adopting a mathematical model of linear speed + annual term + semi-annual term + jump, and the stability of the reservoir dam and the surrounding GNSS reference station is comprehensively evaluated in combination with a reservoir dam border deformation mechanism, deformation characteristics and the like.

The invention discloses a double-satellite-based real-time precise single-point positioning system combined positioning method, which synchronously receives and decodes real-time satellite orbits, clock correction and code deviation correction of PPP-B2b and HAS, and realizes real-time precise single-point positioning of a user side combined with GPS + BDS-3 + Galileo three systems through strategies such as orbital combination and clock correction optimization and switching. In the aspect of orbit correction, two satellite-based PPP orbit product references are unified through a Helmert similarity transformation model, and a combined orbit product is generated by adopting a weight adjustment strategy combining a priori fixed weight and a posterior fixed weight. In the aspect of the clock correction number, aiming at the problem that different satellite-based correction numbers are inconsistent in time reference, clock correction type consistency detection between a front epoch and a rear epoch is carried out, and ambiguity parameters of corresponding satellites are reset in time.

The invention provides a railway user location service method and system based on satellite-ground collaboration, and relates to the technical field of wireless communication networks, and the method comprises the steps: constructing a coordinate reference unified frame and a seamless positioning model for a satellite-ground collaboration system, a positioning service is provided for a server side of precise single-point positioning and real-time dynamic positioning services and a railway user side, and Beidou satellite-based precise single-point positioning service precision, space abnormal signals, orbit integrity and environmental noise corresponding to a satellite-ground cooperative system are monitored; and broadcasting the positioning fusion service data to the railway user side in real time based on the satellite-ground cooperative system, so that the railway user side optimizes self positioning data based on the positioning fusion service data. According to the invention, high-precision position service can be provided for railway users in a railway complex environment, and the railway scene positioning precision, real-time performance and reliability can be improved, so that wider railway application requirements are met.