A navigation satellite orbit determination precision improvement method based on pseudo-range bias correction

Abstract

The present application relates to a kind of navigation satellite orbit determination precision promotion method based on pseudo-range deviation correction, belong to satellite navigation field, the method is combined with global distribution ground station dual-frequency pseudo-range observation value and external precise orbit clock difference product constructs ionosphere-free combination observation equation, through precise point positioning calculation receiver coordinate and constructs posteriori pseudo-range residual equation;According to the grouping of receiver model and the application of zero-sum constraint, align receiver clock difference, through multi-epoch joint network least square batch processing each type receiver is solved to each navigation satellite dual-frequency ionosphere-free combination pseudo-range deviation value;According to the receiver model of ground station, select the pseudo-range deviation value of corresponding type, deduct from dual-frequency ionosphere-free combination pseudo-range observation, obtain the pseudo-range observation of correction;Using the pseudo-range observation of correction and carrier phase observation, joint solution navigation satellite precise orbit parameter.The present application has significantly improved the navigation satellite orbit determination precision and spatial reference consistency level.

Description

Technical Field

[0001] This invention relates to the fields of satellite navigation, aerospace measurement and control, and in particular to a method for improving the orbit determination accuracy of navigation satellites based on pseudorange deviation correction. Background Technology

[0002] As a critical national spatiotemporal infrastructure, satellite navigation systems provide precise orbits and clock biases, which are essential prerequisites for achieving high-precision positioning, navigation, and timing services. Currently, the International GNSS Service (IGS) conducts precise orbit determination for navigation satellites through approximately 500 ground monitoring stations distributed globally. These stations are equipped with receivers from different manufacturers, with numerous models and significant differences in hardware parameters (such as front-end bandwidth and correlator spacing).

[0003] Due to the non-ideal characteristics of navigation satellite payloads, downlink navigation signals exhibit varying degrees of waveform distortion. Different types of receivers process this distortion differently, resulting in pseudorange measurement constant deviations (code bias) of varying magnitudes and signs for the same satellite, or even for different satellites, by different receiver models. The characteristics of this deviation are: different pseudorange biases for different satellites by the same receiver; different pseudorange biases for the same satellite by different receiver models; and in precise orbit determination processing, these errors cannot be effectively absorbed by satellite clock bias or receiver clock bias parameters, becoming an independent source of systematic error.

[0004] In dual-frequency, ionospherically insulated processing, pseudorange bias is amplified, directly affecting the accuracy of the orbit determination observation model and leading to increased errors in orbit parameter calculation. In the current IGS standard orbit determination strategy, phase observations are the primary constraint, while pseudorange is mainly used for initial clock bias values ​​and anomaly detection. Therefore, the pseudorange bias problem has long remained unresolved systematically.

[0005] In the prior art, the solutions related to this invention mainly include: correcting rotation errors by introducing low-orbit satellite observation data and combining them with space reference conversion parameters, but without addressing pseudorange deviations caused by differences in receiver models; improving orbit determination geometry by fusing space-based and ground-based observation data, but without proposing a method for calibrating and correcting pseudorange deviations; and improving orbit determination accuracy by optimizing dual-frequency ambiguity fixing strategies, but neglecting the impact of systematic deviations in pseudorange observation values.

[0006] Therefore, how to effectively calibrate and systematically correct pseudorange deviations under the condition of a globally distributed heterogeneous GNSS receiver network, and improve the precision orbit determination accuracy of navigation satellites, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] In view of the above analysis, the present invention aims to disclose a method for improving the orbit determination accuracy of navigation satellites based on pseudorange deviation correction, thereby solving the above-mentioned technical problems.

[0008] This invention discloses a method for improving the orbit determination accuracy of navigation satellites based on pseudorange bias correction, comprising:

[0009] S1. Carrier phase smoothing is performed on dual-frequency pseudorange observations from globally distributed ground stations. An ionospheric-free combined observation equation is constructed by combining external precision orbital clock error products. Receiver coordinates are calculated through precise single-point positioning, and a post-test pseudorange residual equation is constructed.

[0010] S2. Group the receivers by model and apply zero-sum constraints, align the receiver clock biases, and calculate the pseudorange deviation values ​​of the dual-frequency non-ionospheric combination of each receiver model to each navigation satellite through multi-epoch joint network least squares batch processing.

[0011] S3. Based on the ground station receiver model, select the corresponding pseudorange deviation value and subtract it from the pseudorange observation of the dual-frequency non-ionospheric combination to obtain the corrected pseudorange observation.

[0012] S4. Using the corrected pseudorange observations and carrier phase observations, the precise orbital parameters of the navigation satellite are jointly calculated.

[0013] Further, S1 includes:

[0014] S101. For the raw pseudorange observations of each ground station receiver distributed globally at the first frequency F1 and the second frequency F2, smooth the original pseudorange observations using the carrier phase observations to reduce pseudorange measurement noise.

[0015] S102. Using the smoothed dual-frequency pseudorange observations and carrier phase observations, combined with the navigation satellite precision orbit and clock error products provided by the IGS analysis center as known information, the observation data of the two frequency points are linearly combined in an ionospheric-free combination method to establish an ionospheric-free combination observation equation that eliminates the influence of the first-order delay of the ionosphere.

[0016] S103. Based on the above ionospheric-free combined observation equations, a precise single-point positioning model is used to estimate parameters, calculate the precise three-dimensional coordinates of the receivers at each ground station, and estimate the receiver clock error, zenith tropospheric delay, and carrier phase ambiguity parameters.

[0017] S104. Using the receiver coordinates and parameters obtained from the precise single-point positioning calculation, the geometric distance from the satellite to the receiver is recalculated. Known correction terms, including geometric distance, satellite clock error, tropospheric delay, and relativistic effects, are deducted from the pseudorange observations of the ionosphere-free combination. Finally, the post-hoc pseudorange residual equation, which retains the receiver clock error and the pseudorange bias information of the dual-frequency ionosphere-free combination, is obtained.

[0018] Furthermore, in S102, the ionospheric-free combination equation for constructing GNSS satellite pseudorange and carrier phase observation data is as follows:

[0019] ;

[0020] ;

[0021] in, and These are the combined observations of dual-frequency pseudorange and carrier phase without ionosphere at the two frequency points F1 and F2, respectively. The geometric distance from the satellite to the receiver. The speed of light in a vacuum; and These are the satellite clock bias and receiver clock bias, respectively, including the receiver and satellite hardware delays after the ionosphere-free combination; This is a correction term for relativistic effects; For tropospheric delay; For wavelengths without ionosphere, For ionospheric composite phase ambiguity, For multipath error after ionosphere-free combination, The errors after ionospherically-free assembly include antenna phase center deviation and receiver observation noise. , These are the carrier frequency values ​​for the two frequency points F1 and F2; This is a correction for the phase entanglement effect.

[0022] Furthermore, in S104, the post-hoc pseudorange residual equation is:

[0023] ;

[0024] in, To deduct the geometric distance from the satellite to the receiver Satellite clock bias Tropospheric correction Relativity correction The pseudorange residual portion after; For receiver clock bias, For receiver For satellites The pseudorange deviation value of the dual-frequency non-ionospheric combination.

[0025] Further, S2 includes:

[0026] S201. Divide all globally distributed ground station receivers into different groups according to manufacturer and model, ensuring that receivers within the same group are of identical model; count the total number of receivers. Number of groups and the number of receivers in each group , ;

[0027] S202. Apply zero-sum constraints to each group of receiver models to eliminate the rank deficiency problem between pseudorange bias parameters.

[0028] S203. Simplify the post-hoc pseudorange residual equation into a linear expression containing only receiver clock error and pseudorange bias, and apply this to all... Each receiver is uniformly numbered, and a serial number system is established for each receiver. To its corresponding model group The mapping relationship provides an index basis for subsequent matrix construction;

[0029] S204. Select the first receiver as the time reference, construct clock bias alignment constraints to eliminate reference differences, and based on the reference, receiver model grouping mapping relationship and zero-sum constraint conditions, integrate the a priori residual equations of all receivers under all epochs, and assemble the whole network method equations.

[0030] S205. The least squares batch processing algorithm is used to solve the post-test residual equation, and the clock bias parameters of all receivers and the pseudorange deviation values ​​of dual-frequency non-ionospheric combination of each type of receiver for each navigation satellite are estimated simultaneously to achieve accurate extraction of the deviation parameters.

[0031] Furthermore, in S202, the zero-sum constraint condition applied to each group of receiver models is as follows:

[0032] ;

[0033] In the formula, For the first All receivers in the group are paired with the first The pseudorange bias value of the dual-frequency non-ionospheric combination of the satellites; the zero-sum constraint condition specifies the first Group receivers for all The sum of the pseudorange deviations of the navigation satellites is zero, thus establishing a reference frame for the pseudorange deviations.

[0034] Furthermore, in S203, the established linear expression is:

[0035] ;

[0036] In the formula, For the first Group 1 Taiwan receiver to satellite The pseudo-range residuals after verification; For the first Group 1 Receiver clock bias of the receiver; , Representing the Group receiver, This represents the index number of the receiver in each group, in group 1. The maximum value is In the In the group The maximum value is And so on, in the 1st In the group The maximum value is ; .

[0037] Furthermore, in S204, the whole-network method equation is:

[0038] ;

[0039] Among them, the observation vector To deduct residuals after satellite-to-ground distance, satellite clock error, tropospheric error, and relativistic corrections, a matrix is ​​designed. The intermediate parameters characterize the contribution relationship between receiver clock error and pseudorange bias to the residuals; the parameter vector to be determined For including The parameters to be estimated include the clock bias of the receiver and the pseudorange deviation of all different types of ground station receivers for each navigation satellite;

[0040] Observation vector for Dimensional vector:

[0041] ;

[0042] Parameter vector to be determined for Dimensional vector:

[0043] ;

[0044] Design Matrix The number of rows in the middle is: Taiwan receiver Each satellite corresponds to one observation equation in each row.

[0045] Design Matrix The column number is: Individual receiver clock bias + Group receiver × Each satellite has a column corresponding to a parameter to be estimated.

[0046] Design Matrix All elements in the middle are either 0 or 1; including the preceding elements. The receiver clock bias portion and the remaining pseudorange bias portion of the array;

[0047] The receiver clock bias section, if a certain row of observations comes from the first... The receiver, then the line number The column coefficient is 1;

[0048] The pseudorange bias component, if a row of observations comes from the first row... Group receiver, and the observation satellite is the first If there are 1 satellite, then that row corresponds to 1 satellite. The column coefficient is 1.

[0049] Furthermore, in S3, for the first... Group receiver For navigation satellites The pseudorange observations of the dual-frequency non-ionospheric combination after correcting for pseudorange bias are as follows:

[0050] ;

[0051] in, For ground station receiver For navigation satellites Dual-frequency ionospheric-free original pseudorange observations, for The corresponding model of receiver supports navigation satellites The pseudorange deviation value, The pseudorange observations of the dual-frequency non-ionospheric combination are corrected for pseudorange bias.

[0052] Further, S4 includes:

[0053] S401. Dual-frequency ionospheric-free combined pseudorange observations and carrier phase observations after correcting pseudorange bias using globally distributed ground station receivers;

[0054] S402. Fix the coordinates of each station to precise known values, and use the least squares batch processing algorithm to jointly solve the initial satellite position and velocity, solar radiation pressure parameters, satellite and station receiver clock error parameters, zenith tropospheric delay, and carrier phase ambiguity parameters as parameters to be estimated.

[0055] S403. Correct the pseudorange deviation based on the solution results to achieve precise orbit determination of navigation satellites.

[0056] This invention can achieve one of the following beneficial effects:

[0057] This invention effectively suppresses system errors introduced by receiver-end hardware delay, significantly improving the orbit determination accuracy of navigation satellites and their consistency with space references; among which,

[0058] Based on the network-wide calculation of the residual after precise single-point positioning verification, without the need for parallel receiver deployment, it directly achieves high-precision calibration of pseudorange deviation of dual-frequency non-ionospheric combination receivers of different models in the global heterogeneous monitoring network, solving the application bottleneck of traditional methods that can only calculate inter-frequency deviation.

[0059] In the precise orbit determination of navigation satellites, the pseudorange deviation of different receiver models is systematically corrected. By constructing a refined measurement model, the deviation is unified to the same reference benchmark, eliminating the impact of this error on orbit calculation from the root and improving orbit determination accuracy.

[0060] By connecting the pseudorange deviation extraction and orbit determination correction stages, the calibration results can be directly applied to the subsequent orbit determination process without additional adaptation processing. This approach balances high precision with engineering practicality and is particularly suitable for large-scale and complex monitoring networks with hundreds of stations and dozens of receiver models worldwide. Attached Figure Description

[0061] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0062] Figure 1 This is a flowchart of the method for improving the orbit determination accuracy of navigation satellites based on pseudorange deviation correction in an embodiment of the present invention. Detailed Implementation

[0063] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0064] One embodiment of the present invention discloses a method for improving the orbit determination accuracy of navigation satellites based on pseudorange deviation correction, such as... Figure 1 As shown, it includes:

[0065] S1. Carrier phase smoothing is performed on dual-frequency pseudorange observations from globally distributed ground stations. An ionospheric-free combined observation equation is constructed by combining external precision orbital clock error products. Receiver coordinates are calculated through precise single-point positioning, and a post-test pseudorange residual equation is constructed.

[0066] S2. Group the receivers by model and apply zero-sum constraints, align the receiver clock biases, and calculate the pseudorange deviation values ​​of the dual-frequency non-ionospheric combination of each receiver model to each navigation satellite through multi-epoch joint network least squares batch processing.

[0067] S3. Based on the ground station receiver model, select the corresponding pseudorange deviation value and subtract it from the pseudorange observation of the dual-frequency non-ionospheric combination to obtain the corrected pseudorange observation.

[0068] S4. Using the corrected pseudorange observations and carrier phase observations, the precise orbital parameters of the navigation satellite are jointly calculated.

[0069] Specifically, S1 includes:

[0070] S101. For the raw pseudorange observations of each ground station receiver distributed globally at the first frequency F1 and the second frequency F2, smooth the original pseudorange observations using the carrier phase observations to reduce pseudorange measurement noise.

[0071] S102. Using the smoothed dual-frequency pseudorange observations and carrier phase observations, combined with the navigation satellite precision orbit and clock error products provided by the IGS analysis center as known information, the observation data of the two frequency points are linearly combined in an ionospheric-free combination method to establish an ionospheric-free combination observation equation that eliminates the influence of the first-order delay of the ionosphere.

[0072] The ionospheric-free combination equations for GNSS satellite pseudorange and carrier phase observation data are constructed as follows:

[0073] ;

[0074] ;

[0075] in, and These are the combined observations of dual-frequency pseudorange and carrier phase without ionosphere at the two frequency points F1 and F2, respectively. The geometric distance from the satellite to the receiver. The speed of light in a vacuum; and These are the satellite clock bias and receiver clock bias, respectively, including the receiver and satellite hardware delays after the ionosphere-free combination; This is a correction term for relativistic effects; For tropospheric delay; For wavelengths without ionosphere, For ionospheric composite phase ambiguity, This refers to the multipath error after ionosphere-free combination. This includes errors such as antenna phase center deviation and receiver observation noise after ionospheric-free assembly. , These are the carrier frequency values ​​for the two frequency points F1 and F2; This is a correction for the phase entanglement effect.

[0076] S103. Based on the above ionospheric-free combined observation equations, a precise single-point positioning model is used to estimate parameters, calculate the precise three-dimensional coordinates of the receivers at each ground station, and estimate the receiver clock error, zenith tropospheric delay, and carrier phase ambiguity parameters.

[0077] In this step, the least squares batch processing or Kalman filtering solution methods disclosed in existing literature can be used as a reference. The three-dimensional coordinates of the station, receiver clock error, zenith tropospheric delay, and carrier phase ambiguity are taken as the parameter vector to be estimated. These parameters are substituted into the IGS precise orbit / clock error product to fix the satellite end error. The joint estimation and separation of all parameters are achieved through the overall adjustment of multi-epoch observation data. The precise three-dimensional coordinates of the receivers at each ground station are calculated, and the receiver clock error, zenith tropospheric delay, and carrier phase ambiguity parameters are estimated at the same time.

[0078] S104. Using the receiver coordinates and parameters obtained from the precise single-point positioning calculation, the geometric distance from the satellite to the receiver is recalculated. Known correction terms, including geometric distance, satellite clock error, tropospheric delay, and relativistic effects, are deducted from the pseudorange observations of the ionosphere-free combination. Finally, the post-hoc pseudorange residual equation, which retains the receiver clock error and the pseudorange bias information of the dual-frequency ionosphere-free combination, is obtained.

[0079] In S104, the post-hoc pseudorange residual equation is:

[0080] ;

[0081] in, To deduct the distance between the satellite and the ground Satellite clock bias Tropospheric correction Relativity correction The pseudorange residual portion after; For receiver clock bias, For receiver For satellites The pseudorange deviation value of the dual-frequency non-ionospheric combination.

[0082] Specifically, S2 includes:

[0083] S201. All ground station receivers distributed globally are uniformly numbered and divided into different groups according to manufacturer and model, ensuring that receivers within the same group are of identical model; the total number of receivers is then tallied. Number of groups and the number of receivers in each group , ;

[0084] S202. Apply zero-sum constraints to each group of receiver models to eliminate the rank deficiency problem between pseudorange bias parameters.

[0085] In this step, the zero-sum constraint applied to each group of receiver models is as follows:

[0086] ;

[0087] In the formula, For the first All receivers in the group are paired with the first The pseudorange bias value of the dual-frequency non-ionospheric combination of the satellites; the zero-sum constraint condition specifies the first Group receivers for all The sum of the pseudorange deviations of the navigation satellites is zero, thus establishing a reference frame for the pseudorange deviations.

[0088] Based on the characteristics of the pseudorange bias parameter, different receivers within the same group will have the same pseudorange bias value for the same satellite.

[0089] Right now, , ; For the first Group 1 The pseudorange deviation of the dual-frequency non-ionospheric combination of the receiver.

[0090] S203. Simplify the post-hoc pseudorange residual equation into a linear expression containing only receiver clock error and pseudorange bias, and establish a system based on receiver serial number. To its corresponding model group The mapping relationship provides an index basis for subsequent matrix construction;

[0091] In this step, the established linear expression is:

[0092] ;

[0093] In the formula, For the first Group 1 Taiwan receiver to satellite The pseudo-range residuals after verification; For the first Group 1 Receiver clock bias of the receiver; , Representing the Group receiver, This represents the index number of the receiver in each group, in group 1. The maximum value is In Group 2 The maximum value is And so on, in the 1st Group The maximum value is ; .

[0094] S204. Select the first receiver as the time reference, construct clock bias alignment constraints to eliminate reference differences, and based on the reference, receiver model grouping mapping relationship and zero-sum constraint conditions, integrate the a priori residual equations of all receivers under all epochs, and assemble the whole network method equations.

[0095] In this step, the whole-network method equation is:

[0096] ;

[0097] Among them, the observation vector To deduct residuals after satellite-to-ground distance, satellite clock error, tropospheric error, and relativistic corrections, a matrix is ​​designed. The intermediate parameters characterize the contribution relationship between receiver clock error and pseudorange bias to the residuals; the parameter vector to be determined For including The parameters to be estimated include the clock bias of the receiver and the pseudorange deviation of all different types of ground station receivers for each navigation satellite;

[0098] Observation vector for Dimensional vector:

[0099] ;

[0100] Parameter vector to be determined for Dimensional vector:

[0101] ;

[0102] Design Matrix The number of rows in the middle is: Taiwan receiver Each satellite corresponds to one observation equation in each row.

[0103] Design Matrix The column number is: Individual receiver clock bias + Group receiver × Each satellite has a column corresponding to a parameter to be estimated.

[0104] Design Matrix All elements in the middle are either 0 or 1; including the preceding elements. The receiver clock bias portion and the remaining pseudorange bias portion of the array;

[0105] The receiver clock bias section, if a certain row of observations comes from the first... The receiver, then the line number The column coefficient is 1;

[0106] The pseudorange bias component, if a row of observations comes from the first row... Group receiver, and the observation satellite is the first If there are 1 satellite, then that row corresponds to 1 satellite. The column coefficient is 1, and the rest... The coefficient of each deviation column is 0.

[0107] S205. The least squares batch processing algorithm is used to solve the post-test residual equation, and the clock bias parameters of all receivers and the pseudorange deviation values ​​of dual-frequency non-ionospheric combination of each type of receiver for each navigation satellite are estimated simultaneously to achieve accurate extraction of the deviation parameters.

[0108] In the least squares batch processing, a diagonal weight matrix is ​​first constructed based on the prior error of each observation determined by the observation noise model and empirical statistics of the signal-to-noise ratio. Stations or satellites with poor observation quality are assigned smaller weights to suppress the impact of abnormal observations on parameter estimation.

[0109] When solving, the clock bias of the first receiver is set. As a baseline constraint, it is eliminated from the parameter vector to achieve relative reduction of the clock error parameter. Simultaneously, S202's... Zero-sum constraint equations The virtual observation equation is incorporated into the normal equation to eliminate the rank deficiency problem between pseudorange bias and receiver clock error.

[0110] For large-scale parameter calculations, sparse matrix storage and ultra-relaxed iterative methods can be used to improve efficiency. After calculation, the output parameter estimates and covariance matrix are calculated. The accuracy is calibrated by evaluating the mean square error of the deviation parameters, and out-of-limit parameters are used with reduced weight to ensure reliable and stable extraction results.

[0111] Specifically, in S3, pseudorange bias correction is performed in the dual-frequency pseudorange combined observation of navigation satellites by the ground station receiver. Specifically, based on the receiver model, the pseudorange bias value of the corresponding receiver model is extracted and subtracted from the dual-frequency pseudorange observation.

[0112] For the Group receiver For navigation satellites The pseudorange observations of the dual-frequency non-ionospheric combination after correcting for pseudorange bias are as follows:

[0113] ;

[0114] in, For ground station receiver For navigation satellites Dual-frequency ionospheric-free original pseudorange observations, for The corresponding model of receiver supports navigation satellites The pseudorange deviation value, The pseudorange observations of the dual-frequency non-ionospheric combination are corrected for pseudorange bias.

[0115] Specifically, S4 includes:

[0116] S401. Dual-frequency ionospheric-free combined pseudorange observations and carrier phase observations after correcting pseudorange bias using globally distributed ground station receivers;

[0117] S402. Fix the coordinates of each station to precise known values, and use the least squares batch processing algorithm to jointly solve the initial satellite position and velocity, solar radiation pressure parameters, satellite and station receiver clock error parameters, zenith tropospheric delay, and carrier phase ambiguity parameters as parameters to be estimated.

[0118] Specifically, the Gauss-Newton iterative method is used, with initial values ​​taken from broadcast ephemeris and SINEX files; the pseudorange observations employ modified pseudorange observations. The phase observations are calculated using carrier phase observations that are synchronously resolved with the corrected pseudorange. ; Dynamic constraints employ prior constraints on solar radiation pressure parameters; such as The convergence criterion is that the parameter increment is less than a set threshold or the residual rate of change is less than a set threshold.

[0119] S403. Correct the pseudorange deviation based on the solution results to achieve precise orbit determination of navigation satellites.

[0120] In summary, the solution of this invention effectively suppresses system errors introduced by receiver-end hardware delay, significantly improving the orbit determination accuracy of navigation satellites and the consistency level with space references; wherein,

[0121] Based on the network-wide calculation of the residual after precise single-point positioning verification, without the need for parallel receiver deployment, it directly achieves high-precision calibration of pseudorange deviation of dual-frequency non-ionospheric combination receivers of different models in the global heterogeneous monitoring network, solving the application bottleneck of traditional methods that can only calculate inter-frequency deviation.

[0122] In the precise orbit determination of navigation satellites, the pseudorange deviation of different receiver models is systematically corrected. By constructing a refined measurement model, the deviation is unified to the same reference benchmark, eliminating the impact of this error on orbit calculation from the root and improving orbit determination accuracy.

[0123] By connecting the pseudorange deviation extraction and orbit determination correction stages, the calibration results can be directly applied to the subsequent orbit determination process without additional adaptation processing. This approach balances high precision with engineering practicality and is particularly suitable for large-scale and complex monitoring networks with hundreds of stations and dozens of receiver models worldwide.

[0124] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for improving the orbit determination accuracy of navigation satellites based on pseudorange deviation correction, characterized in that, include: S1. Carrier phase smoothing is performed on dual-frequency pseudorange observations from globally distributed ground stations. An ionospheric-free combined observation equation is constructed by combining external precision orbital clock error products. Receiver coordinates are calculated through precise single-point positioning, and a post-test pseudorange residual equation is constructed. S2. Group the receivers by model and apply zero-sum constraints, align the receiver clock biases, and calculate the pseudorange deviation values ​​of the dual-frequency non-ionospheric combination of each receiver model to each navigation satellite through multi-epoch joint network least squares batch processing. S3. Based on the ground station receiver model, select the corresponding pseudorange deviation value and subtract it from the pseudorange observation of the dual-frequency non-ionospheric combination to obtain the corrected pseudorange observation. S4. Using the corrected pseudorange observations and carrier phase observations, the precise orbital parameters of the navigation satellite are jointly calculated. The S2 includes: S201. Divide all globally distributed ground station receivers into different groups according to manufacturer and model, ensuring that receivers within the same group are of identical model; count the total number of receivers. Number of groups and the number of receivers in each group , ; S202. Apply zero-sum constraints to each group of receiver models to eliminate the rank deficiency problem between pseudorange bias parameters. S203. Simplify the post-hoc pseudorange residual equation into a linear expression containing only receiver clock error and pseudorange bias, and apply this to all... Each receiver is uniformly numbered, and a serial number system is established for each receiver. To its corresponding model group The mapping relationship provides an index basis for subsequent matrix construction; S204. Select the first receiver as the time reference, construct clock bias alignment constraints to eliminate reference differences, and based on the time reference, receiver model grouping mapping relationship and zero-sum constraint conditions, integrate the a priori pseudorange residual equations of all receivers under all epochs, and assemble the whole network method equations. S205. The least squares batch processing algorithm is used to solve the post-approval pseudorange residual equation, and the clock error parameters of all receivers and the pseudorange deviation values ​​of dual-frequency non-ionospheric combination of each type of receiver for each navigation satellite are estimated simultaneously to achieve accurate extraction of the deviation parameters. In S202, the zero-sum constraint condition applied to each group of receiver models is as follows: ； In the formula, For the first All receivers in the group are paired with the first The pseudorange bias value of the dual-frequency non-ionospheric combination of the satellites; the zero-sum constraint condition specifies the first Group receivers for all The sum of the pseudorange deviation values ​​of the navigation satellites is zero, thus establishing a reference frame for the pseudorange deviation; In S203, the established linear expression is: ； In the formula, For the first Group 1 Taiwan receiver to satellite The pseudo-range residuals after verification; For the first Group 1 Receiver clock bias of the receiver; , Representing the Group receiver, This represents the index number of the receiver in each group, in group 1. The maximum value is In the In the group The maximum value is And so on, in the 1st In the group The maximum value is ; ; In S204, the whole-network equation is: ； Among them, the observation vector To deduct the residuals after corrections for satellite-to-ground distance, satellite clock error, tropospheric delay, and relativistic effects, a matrix is ​​designed. The intermediate parameters characterize the contribution relationship between receiver clock error and pseudorange bias to the residuals; the parameter vector to be determined For including The parameters to be estimated include the clock bias of the receiver and the pseudorange deviation of all different types of ground station receivers for each navigation satellite; Observation vector for Dimensional vector: ； Parameter vector to be determined for Dimensional vector: ； Design Matrix The number of rows in the middle is: Taiwan receiver Each satellite corresponds to one observation equation in each row. Design Matrix The column number is: Individual receiver clock bias + Group receiver × Each satellite has a column corresponding to a parameter to be estimated. Design Matrix All elements in the middle are either 0 or 1; including the preceding elements. The receiver clock bias portion and the remaining pseudorange bias portion of the array; The receiver clock bias section, if a certain row of observations comes from the first... The receiver, then the line number The column coefficient is 1; The pseudorange bias component, if a row of observations comes from the first row... Group receiver, and the observation satellite is the first If there are 1 satellite, then that row corresponds to 1 satellite. The column coefficient is 1.

2. The method for improving the orbit determination accuracy of navigation satellites based on pseudorange deviation correction according to claim 1, characterized in that, S1 includes: S101. For the raw pseudorange observations of each ground station receiver distributed globally at the first frequency F1 and the second frequency F2, smooth the original pseudorange observations using the carrier phase observations to reduce pseudorange measurement noise. S102. Using the smoothed dual-frequency pseudorange observations and carrier phase observations, combined with the navigation satellite precision orbit and clock error products provided by the IGS analysis center as known information, the observation data of the two frequency points are linearly combined in an ionospheric-free combination method to establish an ionospheric-free combination observation equation that eliminates the influence of the first-order delay of the ionosphere. S103. Based on the ionospheric-free combined observation equation, a precise single-point positioning model is used to estimate parameters, calculate the precise three-dimensional coordinates of the receivers at various ground stations, and estimate the receiver clock error, zenith tropospheric delay, and carrier phase ambiguity parameters. S104. Using the receiver coordinates and parameters obtained from the precise single-point positioning calculation, the geometric distance from the satellite to the receiver is recalculated. Known correction terms, including geometric distance, satellite clock error, tropospheric delay, and relativistic effects, are deducted from the pseudorange observations of the ionosphere-free combination. Finally, the post-hoc pseudorange residual equation, which retains the receiver clock error and the pseudorange bias information of the dual-frequency ionosphere-free combination, is obtained.

3. The method for improving the orbit determination accuracy of navigation satellites based on pseudorange deviation correction according to claim 2, characterized in that, In step S102, the ionospheric-free combined observation equation for GNSS satellite pseudorange and carrier phase observation data is constructed as follows: ； ； in, and These are the combined observations of dual-frequency pseudorange and carrier phase without ionosphere at the two frequency points F1 and F2, respectively. The geometric distance from the satellite to the receiver. The speed of light in a vacuum; and These are the satellite clock bias and receiver clock bias, respectively, including the receiver and satellite hardware delays after the ionosphere-free combination; This is a correction term for relativistic effects; For tropospheric delay; For wavelengths without ionosphere, For ionospheric composite phase ambiguity, For multipath error after ionosphere-free combination, The errors after ionospherically-free assembly include antenna phase center deviation and receiver observation noise. , These are the carrier frequency values ​​for the two frequency points F1 and F2; This is a correction for the phase entanglement effect.

4. The method for improving the orbit determination accuracy of navigation satellites based on pseudorange deviation correction according to claim 3, characterized in that, In S104, the post-hoc pseudorange residual equation is: ； in, To deduct the geometric distance from the satellite to the receiver Satellite clock bias Tropospheric delay Relativistic effect correction term The pseudorange residual portion after; For receiver clock bias, For receiver For satellites The pseudorange deviation value of the dual-frequency non-ionospheric combination.

5. The method for improving the orbit determination accuracy of navigation satellites based on pseudorange deviation correction according to claim 1, characterized in that, In S3, for the first Group receiver For navigation satellites The pseudorange observations of the dual-frequency non-ionospheric combination after correcting for pseudorange bias are as follows: ； in, For ground station receiver For navigation satellites Dual-frequency ionospheric-free original pseudorange observations, for The corresponding model of receiver supports navigation satellites The pseudorange deviation value, The pseudorange observations of the dual-frequency non-ionospheric combination are corrected for pseudorange bias.

6. The method for improving the orbit determination accuracy of navigation satellites based on pseudorange deviation correction according to claim 5, characterized in that, The S4 includes: S401. Using globally distributed ground station receivers, acquire dual-frequency ionospheric-free combined pseudorange observations and carrier phase observations after pseudorange bias correction. S402. Fix the coordinates of each station to precise known values, and use the least squares batch processing algorithm to jointly solve the initial satellite position and velocity, solar radiation pressure parameters, satellite and station receiver clock error parameters, zenith tropospheric delay, and carrier phase ambiguity parameters as parameters to be estimated. S403. Correct the pseudorange deviation based on the calculation results to achieve precise orbit determination of navigation satellites.

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