A PPP-B2b precise positioning method and system with accelerated convergence

Abstract

The present application is applicable to the field of satellite navigation technology and provides a PPP‑B2b precise positioning method with accelerated convergence, including calculating the satellite precise orbit parameters of each epoch; for the first epoch, obtaining the corresponding satellite precise clock error parameters based on the basic navigation broadcast clock error parameters; for all epochs except the first epoch, calculating the satellite precise clock error parameters of the current epoch based on the PPP‑B2b clock error correction number of the current epoch and the clock error parameter data of the previous epoch; obtaining the O‑C residual information of the dual-frequency observation data in each epoch and constructing the partial derivative information of the dual-frequency observation data to the navigation solution parameters; based on the normal equation matrix and the residual vector, calculating the navigation solution data set of the corresponding epoch. The present application processes the satellite precise clock errors of the first epoch and the subsequent epochs separately, thereby avoiding the deviation error in the PPP‑B2b clock error correction number and shortening the user convergence time.

Description

Technical Field

[0001] The present application belongs to the field of satellite navigation technology, and in particular relates to a PPP-B2b precise positioning method and system with accelerated convergence. Background Art

[0002] In the existing technology, users receive the satellite orbit correction and clock correction numbers broadcast by the Beidou GEO satellite PPP-B2b signal, and use them in conjunction with the navigation message to form precise orbit and clock correction parameters. They then use the acquired multi-frequency pseudorange and phase observation data to complete the positioning solution. Among them, convergence performance is an important indicator of precise positioning services, and user-side algorithm design is an important factor affecting convergence performance. It needs to better adapt to the precise enhancement information characteristics broadcast by the system.

[0003] However, after evaluation of the above technical solutions, it was found that the clock correction number broadcast by the PPP-B2b signal has a constant deviation. The current PPP-B2b user-side algorithm does not fully consider the impact of this deviation parameter, resulting in a long convergence time for PPP-B2b precise positioning, affecting the user experience. Summary of the Invention

[0004] The embodiments of the present application provide a PPP-B2b precise positioning method and system with accelerated convergence, which can avoid the deviation error in the PPP-B2b clock correction number and shorten the user convergence time.

[0005] In a first aspect, an embodiment of the present application provides a PPP-B2b precise positioning method with accelerated convergence, comprising:

[0006] Calculate the precise satellite orbit parameters for each epoch based on the basic navigation message broadcast ephemeris and the precise corrections broadcast by PPP-B2b;

[0007] For the first epoch, the corresponding satellite precise clock error parameters are obtained based on the basic navigation broadcast clock error parameters;

[0008] For all epochs except the first one, the satellite precise clock parameters of the current epoch are calculated based on the PPP-B2b clock correction of the current epoch and the clock parameter data of the previous epoch;

[0009] For all epochs, based on the satellite's precise orbit parameters and satellite's precise clock parameters, a dual-frequency ionosphere-free combination method is used to obtain the OC residual information of the dual-frequency observation data in each epoch and construct the partial derivative information of the dual-frequency observation data with respect to the navigation solution parameters;

[0010] Based on the OC residual information and the partial derivative information, a normal equation matrix and a residual vector are constructed, and based on the normal equation matrix and the residual vector, a navigation solution data set of the corresponding epoch is calculated.

[0011] Furthermore, the calculation of the satellite precise orbit parameters for each epoch based on the basic navigation message broadcast ephemeris and the precise correction numbers broadcast by PPP-B2b includes:

[0012] Based on the basic navigation message broadcast ephemeris, obtain the satellite orbit position corresponding to each epoch;

[0013] Obtain orbit corrections broadcast via PPP-B2b and convert them to the satellite orbit coordinate system;

[0014] Based on the satellite orbit position and the orbit correction number, the precise orbit parameters of the satellite at each epoch are calculated.

[0015] Furthermore, the clock error parameter data includes satellite precise clock error parameters and clock error correction numbers;

[0016] For all epochs except the first one, the satellite precise clock parameters for the current epoch are calculated based on the PPP-B2b clock correction of the current epoch and the clock parameter data of the previous epoch, including:

[0017] Calculate the clock error difference between the current epoch and the previous epoch;

[0018] Based on the clock error difference and the satellite precise clock error parameters of the previous epoch, the satellite precise clock error parameters of the current epoch are obtained.

[0019] Furthermore, the dual-frequency observation data includes pseudorange observation data and carrier phase observation data;

[0020] For all epochs, based on the satellite precise orbit parameters and satellite precise clock parameters, the dual-frequency ionosphere-free combination method is used to obtain the OC residual information of the dual-frequency observation data in each epoch, including:

[0021] Based on the basic navigation message, the single point positioning processing method is used to calculate the clock error parameters and site coordinates of the user receiver;

[0022] Calculating a satellite-to-ground distance between the satellite and the user receiver based on the precise satellite orbit parameters and the site coordinates, wherein the site coordinates represent the coordinates of the user receiver;

[0023] A dual-frequency ionospheric-free combination method is used to perform pseudo-range observations and carrier phase observations on the satellite through the user receiver to obtain pseudo-range observation data and carrier phase observation data.

[0024] Calculate the correlation errors generated by pseudorange observation and carrier phase observation process;

[0025] Based on the clock error parameter, the satellite-to-ground distance, the correlation error and the pseudorange observation data, the OC residual information of the pseudorange observation is calculated using a pseudorange residual equation;

[0026] Based on the clock error parameter, the satellite-to-ground distance, the correlation error and the carrier phase observation data, OC residual information of the carrier phase observation is calculated through a carrier phase residual equation.

[0027] Furthermore, the pseudorange observation and carrier phase observation of the satellite are performed by the user receiver to obtain the pseudorange observation data and the carrier phase observation data, including:

[0028] The pseudorange observation data is obtained by calculation through the pseudorange observation equation, and the carrier phase observation data is obtained by the carrier phase observation equation;

[0029] The specific formula of the pseudorange observation equation is:

[0030]

[0031] The specific formula of the carrier phase observation equation is:

[0032]

[0033] In the pseudorange observation equation and the carrier phase observation equation, The user receiver r represents the satellite s at The pseudo-range observation data of the dual-frequency ionosphere-free combination at the time, The user receiver r represents the satellite s at The carrier phase observation data of the dual-frequency ionospheric-free combination at the time, represents the precise orbit parameters of the satellite, represents the site coordinates of the user receiver, represents the light travel time, represents the speed of light, represents the clock error parameter of the user receiver, represents the satellite precise clock error parameter, represents the tropospheric delay of the satellite-ground line, represents the equivalent wavelength of the dual-frequency ionospheric-free combined phase observation, represents the initial value of the carrier phase ambiguity, represents the correlation error, represents the multipath effect and noise of pseudorange observation data in the dual-frequency ionosphere-free combination, Represents the multipath effect and noise of carrier phase observation data in the dual-frequency ionosphere-free combination.

[0034] Furthermore, the specific formula of the pseudorange residual equation is:

[0035]

[0036] The specific formula of the carrier phase residual equation is:

[0037]

[0038] In the pseudorange residual equation and the carrier phase residual equation, represents the OC of the dual-frequency ionospheric-free combination method, Indicates the carrier phase OC in the dual-frequency ionospheric-free combination method, represents pseudorange observation data, represents the carrier phase observation data, represents the precise orbit parameters of the satellite, represents the site coordinates of the user receiver, represents the speed of light, represents the clock error parameter of the user receiver, represents the satellite precise clock error parameter, represents the tropospheric delay of the satellite-ground line, represents the equivalent wavelength of the dual-frequency ionospheric-free combined phase observation, represents the initial value of the carrier phase ambiguity, Represents the correlation error.

[0039] Furthermore, the navigation solution parameters include receiver position parameters, receiver clock error parameters, tropospheric delay parameters and carrier phase ambiguity parameters;

[0040] The constructing of partial derivative information of dual-frequency observation data with respect to navigation solution parameters includes:

[0041] For the partial derivative information of the receiver position parameter, constructing a position partial derivative function of the dual-frequency observation data with respect to the receiver position parameter;

[0042] For the partial derivative information of the tropospheric delay parameter, constructing a tropospheric partial derivative function of the dual-frequency observation data with respect to the tropospheric delay parameter;

[0043] For the partial derivative information of the receiver clock error parameter, the speed of light To express;

[0044] For the partial derivative information of the carrier phase ambiguity parameter, the equivalent wavelength To express.

[0045] Furthermore, the navigation solution data set includes navigation solution parameters and covariance information of the navigation solution parameters;

[0046] The constructing a normal equation matrix and a residual vector based on the OC residual information and the partial derivative information, and calculating a navigation solution data set of a corresponding epoch based on the normal equation matrix and the residual vector, includes:

[0047] Based on the partial derivative information, construct a partial derivative matrix;

[0048] Constructing a residual vector based on the OC residual information;

[0049] Constructing a constant matrix based on the partial derivative matrix and the residual vector;

[0050] Based on the constant matrix, construct a normal equation matrix;

[0051] Based on the normal equation matrix and the residual vector, a least squares estimation method is used to obtain navigation solution parameters of each epoch and covariance information of the navigation solution parameters.

[0052] Furthermore, for all epochs except the first epoch, before calculating the navigation solution data set of the corresponding epoch, the following is also included:

[0053] Based on the state prediction method of Kalman filtering, the navigation solution data set of the previous epoch is subjected to parameter process noise setting, and the predicted information of the parameters to be estimated at the current epoch is predicted. The predicted information of the parameters to be estimated includes the estimated state of the navigation solution parameters and the covariance information of the navigation solution parameters under the estimated state.

[0054] In a second aspect, an embodiment of the present application provides a PPP-B2b precise positioning system with accelerated convergence, comprising:

[0055] Satellite precise orbit parameter calculation module: used to calculate the precise satellite orbit parameters of each epoch based on the basic navigation message broadcast ephemeris and the precise correction numbers broadcast by PPP-B2b;

[0056] Satellite precise clock error parameter calculation module: used for obtaining the corresponding satellite precise clock error parameters for the first epoch based on the basic navigation broadcast clock error parameters. For all epochs except the first epoch, the satellite precise clock error parameters for the current epoch are calculated based on the PPP-B2b clock error correction number of the current epoch and the clock error parameter data of the previous epoch.

[0057] Dual-frequency observation data processing module: for all epochs, based on the satellite precise orbit parameters and satellite precise clock error parameters, using the dual-frequency ionosphere-free combination method, obtains the OC residual information of the dual-frequency observation data in each epoch and constructs the partial derivative information of the dual-frequency observation data with respect to the navigation solution parameters;

[0058] Navigation solution parameter calculation module: used to construct a normal equation matrix and a residual vector based on the OC residual information and the partial derivative information, and calculate the navigation solution data set of the corresponding epoch based on the normal equation matrix and the residual vector.

[0059] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0060] The present application discloses a PPP-B2b precise positioning method for accelerated convergence, which treats the precise positioning processing of the first epoch and the precise positioning processing of subsequent epochs separately. Specifically, the satellite precise clock errors of the first epoch and subsequent epochs are processed separately, thereby avoiding the bias error in the PPP-B2b clock error correction number and shortening the user convergence time. In addition, for all epochs except the first epoch, before solving the navigation solution parameters, the state of the navigation solution parameters of the current epoch is predicted, thereby improving the estimated accuracy of the parameter estimates of subsequent epochs and improving positioning accuracy and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0062] Figure 1 1 is a flow chart of a PPP-B2b precise positioning method with accelerated convergence provided by one embodiment of the present invention;

[0063] Figure 2 This is a flow chart of a method for positioning a user receiver in the first epoch and subsequent epochs in a PPP-B2b precise positioning method with accelerated convergence provided by one embodiment of the present invention;

[0064] Figure 3 The figure is a schematic structural diagram of a PPP-B2b precise positioning system with accelerated convergence provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0065] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0066] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0067] It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0068] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0069] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0070] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0071] See also Figure 1 As shown, the present invention is a PPP-B2b precise positioning method with accelerated convergence, comprising the following steps:

[0072] S100, calculating the satellite precise orbit parameters for each epoch based on the basic navigation message broadcast ephemeris and the precise corrections broadcast by PPP-B2b;

[0073] In some embodiments, step S100 includes:

[0074] Based on the basic navigation message broadcast ephemeris, obtain the satellite orbit position corresponding to each epoch;

[0075] Obtain orbit corrections broadcast via PPP-B2b and convert them to the satellite orbit coordinate system;

[0076] Based on the satellite orbit position and the orbit correction number, the precise orbit parameters of the satellite at each epoch are calculated.

[0077] Specifically, the basic navigation message broadcast ephemeris includes specific information about the satellite's orbit. Through the basic navigation message broadcast ephemeris, the satellite orbit position corresponding to each epoch can be obtained.

[0078] In this embodiment, the information in the basic navigation message is corrected through PPP-B2b to obtain corresponding precise correction numbers to improve positioning accuracy. The PPP-B2b service then broadcasts the precise correction numbers, enabling the user receiver to achieve high-precision positioning without relying on ground base stations. Specifically, the orbit correction numbers broadcast based on PPP-B2b are obtained and converted into orbit data in the satellite orbit coordinate system, so that the satellite can use the orbit data for precise orbit positioning.

[0079] It can be understood that the specific formula for the satellite's precise orbit parameters is: = ,in, represents the precise orbit parameters of the satellite, Indicates the satellite orbital position obtained through basic navigation broadcast ephemeris, Indicates the orbit correction number broadcasted via PPP-B2b and converted to the satellite orbit coordinate system.

[0080] S200: For the first epoch, obtain corresponding satellite precise clock error parameters based on basic navigation broadcast clock error parameters;

[0081] Specifically, basic navigation messages usually include basic information such as the satellite's orbital parameters and clock error parameters, which are the basis for users to conduct navigation and positioning. Satellites broadcast the above-mentioned broadcast messages in the form of wireless signals. User receivers receive and decode the above-mentioned broadcast messages to obtain satellite position and clock information, and then perform preliminary positioning calculations.

[0082] In this embodiment, the satellite orbital position and satellite precise clock error parameters corresponding to each epoch are obtained through the basic navigation message. Specifically, the basic navigation message includes the basic navigation message broadcast ephemeris and the basic navigation broadcast clock error parameters, wherein the basic navigation message broadcast ephemeris includes specific information of the satellite's motion orbit. The satellite orbital position corresponding to each epoch can be obtained through the basic navigation message broadcast ephemeris. The basic navigation broadcast clock error parameters are used to reflect information such as the deviation, frequency deviation and frequency change rate of the satellite clock. The satellite precise clock error parameters of each epoch can be obtained through the basic navigation broadcast clock error parameters.

[0083] It can be understood that the first epoch is the first time unit for starting precise positioning calculations. The satellite clock error obtained through the basic navigation broadcast clock error parameters can be used to represent the satellite precise clock error corresponding to the first epoch. ,in, represents the satellite precise clock error parameter, Indicates the satellite clock error obtained through the basic navigation broadcast clock error parameters.

[0084] S300, for all epochs except the first epoch, calculate the satellite precise clock error parameters of the current epoch based on the PPP-B2b clock error correction number of the current epoch and the clock error parameter data of the previous epoch;

[0085] In this embodiment, all epochs except the first epoch are subsequent epochs, which represent the time units following the first epoch. Therefore, when calculating the satellite precise clock error parameters of the subsequent epochs, it is necessary to comprehensively consider the PPP-B2b clock error correction number of the previous epoch and the clock error parameter data of the previous epoch.

[0086] In some embodiments, the clock error parameter data includes satellite precise clock error parameters and clock error correction numbers;

[0087] The above step S300 includes:

[0088] Calculate the clock error difference between the current epoch and the previous epoch;

[0089] Based on the clock error difference and the satellite precise clock error parameters of the previous epoch, the satellite precise clock error parameters of the current epoch are obtained.

[0090] In this embodiment, the clock error difference between the clock error correction number of the current epoch and the previous epoch is calculated to constrain the deviation of the basic navigation broadcast clock error parameter between two adjacent epochs, avoid the deviation error caused by the PPP-B2b clock error correction number, and then accurately evaluate the change of the user receiver time, thereby performing more accurate time synchronization, and then obtain the satellite precise clock error parameter of the current epoch by the clock error difference and the satellite precise clock error parameter of the previous epoch. Specifically, the precise clock error of the satellite s in the previous epoch is recorded as , the PPP-B2b clock correction of satellite s in the last epoch is , the PPP-B2b clock correction of satellite s at the current epoch is , then the satellite precise clock error parameters of the current epoch are: .

[0091] In this application, the precise positioning processing of the first epoch and the precise positioning processing of subsequent epochs are treated separately, which is specifically reflected in the separate processing of the satellite precise clock errors of the first epoch and subsequent epochs, thereby avoiding the bias error in the PPP-B2b clock correction number and shortening the user convergence time.

[0092] S400, for all epochs, based on the satellite precise orbit parameters and satellite precise clock error parameters, a dual-frequency ionosphere-free combination method is used to obtain the OC residual information of the dual-frequency observation data in each epoch and construct the partial derivative information of the dual-frequency observation data with respect to the navigation solution parameters;

[0093] In some embodiments, the dual-frequency observation data includes pseudorange observation data and carrier phase observation data;

[0094] Among them, for all epochs, based on the satellite precise orbit parameters and satellite precise clock error parameters, the dual-frequency ionosphere-free combination method is used to obtain the OC residual information of the dual-frequency observation data in each epoch, including:

[0095] Based on the basic navigation message, the single point positioning processing method is used to calculate the clock error parameters and site coordinates of the user receiver;

[0096] Calculating the satellite-to-ground distance between the satellite and the user receiver based on the satellite precise orbit parameters and the site coordinates;

[0097] A dual-frequency ionospheric-free combination method is used to perform pseudo-range observations and carrier phase observations on the satellite through the user receiver to obtain pseudo-range observation data and carrier phase observation data.

[0098] Calculate the correlation errors generated by pseudorange observation and carrier phase observation process;

[0099] Based on the clock error parameter, the satellite-to-ground distance, the correlation error and the pseudorange observation data, the OC residual information of the pseudorange observation is calculated using a pseudorange residual equation;

[0100] Based on the clock error parameter, the satellite-to-ground distance, the correlation error and the carrier phase observation data, OC residual information of the carrier phase observation is calculated through a carrier phase residual equation.

[0101] In this embodiment, a standard single-point positioning method is adopted to obtain the site coordinates and clock error parameters of the user receiver based on the calculation of the basic navigation message. Specifically, a user receiver is used to receive satellite signals from multiple satellites at the same time. By measuring the propagation time of the satellite signal from the satellite to the user receiver and combining the orbit parameters and clock error parameters in the basic navigation message, the least squares algorithm is used to solve the site coordinates and clock error parameters of the user receiver. It can be understood that when positioning is performed by the standard single-point positioning method, due to its relatively low positioning accuracy, the site coordinates and clock error parameters obtained are the approximate coordinates and approximate clock error of the user receiver. Therefore, the calculated site coordinates and clock error parameters need to be combined with dual-frequency observation data to perform residual calculation processing, thereby improving the positioning accuracy of PPP-B2b.

[0102] Specifically, the satellite-to-ground distance between the satellite and the user receiver is obtained using the site coordinates of the user receiver and the precise satellite orbit parameters obtained in step S100, where: .

[0103] In satellite navigation positioning, there is usually a problem of ionospheric delay. In order to eliminate the influence of ionospheric delay, in this embodiment, a dual-frequency ionospheric-free combination method is adopted for the observation data. Based on the property that ionospheric delay is inversely proportional to the square of the frequency, the influence of ionospheric delay is eliminated by combining observation values of two different frequencies. Specifically, the dual-frequency ionospheric-free combination method usually performs pseudorange observation and carrier phase observation on the satellite respectively, and then obtains pseudorange observation data and carrier phase observation data.

[0104] In satellite navigation positioning, due to various physical phenomena, instrument characteristics and environmental factors, such as receiver phase center, relativistic effect, receiver phase center deviation, earth rotation, tide, phase entanglement and other related errors, the above-mentioned related errors usually lead to differences between the final positioning solution and the actual position, and various related errors may exist alone or superimpose on each other, jointly affecting the positioning accuracy. Therefore, in this embodiment, when calculating the OC residual information of the dual-frequency observation data, the above-mentioned related errors need to be considered to improve the final positioning accuracy.

[0105] In some embodiments, performing pseudorange observation and carrier phase observation on a satellite by a user receiver to obtain pseudorange observation data and carrier phase observation data includes:

[0106] The pseudorange observation data is obtained by calculation through the pseudorange observation equation, and the carrier phase observation data is obtained by the carrier phase observation equation;

[0107] The specific formula of the pseudorange observation equation is:

[0108] The specific formula of the carrier phase observation equation is:

[0109] In the pseudorange observation equation and the carrier phase observation equation, The user receiver r represents the satellite s at The pseudo-range observation data of the dual-frequency ionosphere-free combination at the time, The user receiver r represents the satellite s at The carrier phase observation data of the dual-frequency ionospheric-free combination at the time, represents the precise orbit parameters of the satellite, represents the site coordinates of the user receiver, represents the light travel time, represents the speed of light, represents the clock error parameter of the user receiver, represents the satellite precise clock error parameter, represents the tropospheric delay of the satellite-ground line, represents the equivalent wavelength of the dual-frequency ionospheric-free combined phase observation, represents the initial value of the carrier phase ambiguity, represents the correlation error, represents the multipath effect and noise of pseudorange observation data in the dual-frequency ionosphere-free combination, Represents the multipath effect and noise of carrier phase observation data in the dual-frequency ionosphere-free combination.

[0110] In the carrier phase observation process, the integer deviation between the carrier phase observation value and the true distance, that is, the integer ambiguity, must also be considered. Therefore, in the carrier phase observation equation, the equivalent wavelength is The initial value of the carrier phase ambiguity Multiplying them together, we get the equivalent distance value, which is used to reflect the actual distance corresponding to the integer ambiguity in the carrier phase observation value, thereby improving the positioning accuracy and facilitating the error analysis and correction of related errors, thereby further improving the accuracy and reliability of positioning.

[0111] In some embodiments, the specific formula of the pseudorange residual equation is:

[0112] The specific formula of the carrier phase residual equation is:

[0113] In the pseudorange residual equation and the carrier phase residual equation, represents the OC of the dual-frequency ionospheric-free combination method, Indicates the carrier phase OC in the dual-frequency ionospheric-free combination method, represents pseudorange observation data, represents the carrier phase observation data, represents the precise orbit parameters of the satellite, represents the site coordinates of the user receiver, represents the speed of light, represents the clock error parameter of the user receiver, represents the satellite precise clock error parameter, represents the tropospheric delay of the satellite-ground line, represents the equivalent wavelength of the dual-frequency ionospheric-free combined phase observation, represents the initial value of the carrier phase ambiguity, Represents the correlation error.

[0114] In this embodiment, for the pseudorange residual equation or the carrier phase equation, the satellite-to-ground distance, clock error and various related errors are deducted from the corresponding dual-frequency observation data to obtain the corresponding OC residual information. In the above pseudorange residual equation and the carrier phase equation, the “ " represents the clock error, which is calculated by taking the difference between the user receiver's clock error parameters and the satellite's precise clock error parameters to correct the error caused by clock asynchrony, thereby improving positioning accuracy and reliability.

[0115] In some embodiments, the navigation solution parameters include receiver position parameters, receiver clock error parameters, tropospheric delay parameters, and carrier phase ambiguity parameters;

[0116] The constructing of partial derivative information of dual-frequency observation data with respect to navigation solution parameters includes:

[0117] For the partial derivative information of the receiver position parameter, constructing a position partial derivative function of the dual-frequency observation data with respect to the receiver position parameter;

[0118] For the partial derivative information of the tropospheric delay parameter, constructing a tropospheric partial derivative function of the dual-frequency observation data with respect to the tropospheric delay parameter;

[0119] For the partial derivative information of the receiver clock error parameter, the speed of light To express;

[0120] For the partial derivative information of the carrier phase ambiguity parameter, the equivalent wavelength To express.

[0121] In this embodiment, by constructing partial derivative information of the dual-frequency observation data with respect to the navigation solution parameters, the relationship between the dual-frequency observation data and the navigation solution parameters can be more accurately described, thereby helping to reduce errors in the navigation solution process and improve the accuracy of the solution. At the same time, by pre-calculating the partial derivative information of the dual-frequency observation data with respect to the navigation solution parameters, when the navigation solution parameters and the covariance information of the navigation solution parameters are iteratively solved in the subsequent step S500, a more accurate initial value or iteration direction can be provided for the iterative process, thereby accelerating the speed of iterative convergence and reducing calculation time, thereby achieving high-precision and fast navigation positioning.

[0122] Specifically, the speed of light connects three key physical quantities: time, distance, and speed. In the process of navigation and positioning, the speed of light is the basis of the signal propagation speed. Therefore, the speed of light is used to represent the partial derivative information of the receiver clock error parameters, and the equivalent wavelength reflects the periodic characteristics of the carrier signal. The equivalent wavelength is used to represent the partial derivative information of the carrier phase ambiguity parameters, which can intuitively reflect the relationship between the carrier phase observation and the ambiguity parameters; the position partial derivative function is constructed through the difference between the user receiver and the satellite, and the partial derivative information of the receiver position parameters is calculated, which helps to accurately reflect the impact of small changes in the observation data on the receiver position during the navigation solution process, thereby improving the positioning accuracy; the tropospheric partial derivative function is constructed through the mapping function of the current user receiver and satellite combination to the tropospheric delay, and the partial derivative information of the tropospheric delay parameters is calculated, which helps to correct the error caused by the tropospheric delay, thereby improving the positioning accuracy of the satellite navigation system.

[0123] Specifically, the specific formula of the position partial derivative function taking pseudorange observation data as an example is:

[0124] The specific formula of the tropospheric partial derivative function taking pseudorange observation data as an example is: in, represents the mapping function of the current user receiver and satellite combination to the tropospheric delay, Represents tropospheric parameters.

[0125] S500: constructing a normal equation matrix and a residual vector based on the OC residual information and the partial derivative information, and calculating and obtaining a navigation solution data set of a corresponding epoch based on the normal equation matrix and the residual vector.

[0126] In some embodiments, the navigation solution dataset includes navigation solution parameters and covariance information of the navigation solution parameters, wherein the above step S500 includes:

[0127] Based on the partial derivative information, construct a partial derivative matrix;

[0128] Constructing a residual vector based on the OC residual information;

[0129] Constructing a constant matrix based on the partial derivative matrix and the residual vector;

[0130] Based on the constant matrix, construct a normal equation matrix;

[0131] Based on the normal equation matrix and the residual vector, a least squares estimation method is used to obtain navigation solution parameters of each epoch and covariance information of the navigation solution parameters.

[0132] In this embodiment, the partial derivative information of each navigation solution parameter in step S400 is obtained, and a partial derivative matrix is constructed to facilitate subsequent iterative calculations. Specifically, the partial derivative matrix is: , and then constructing a constant matrix based on the partial derivative matrix and the OC residual information, specifically including:

[0133] Based on the OC residual information, a residual vector is constructed, and the residual vector is specifically:

[0134]

[0135] Based on the residual vector and the partial derivative matrix, a constant matrix is constructed. The constant matrix is specifically:

[0136] In this embodiment, a constant matrix is calculated based on the partial derivative matrix and the OC residual information of the dual-frequency observation data, which is used to reflect the projection of the difference between the dual-frequency observation data and the current parameter estimation value in the parameter space.

[0137] In one possible embodiment, the normal equation matrix is specifically: , where A is the dual-frequency observation data matrix.

[0138] In this embodiment, based on the normal equation matrix and residual vector, the navigation solution parameters for the user receiver in each epoch are iteratively calculated using the least squares estimation method. The navigation solution parameters include receiver position parameters, receiver clock error parameters, tropospheric delay parameters, and phase ambiguity parameters. Specifically, the least squares estimation method can be used to iteratively process the aforementioned navigation solution parameters. This involves repeatedly adjusting parameter estimates and recalculating the OC residuals and normal equations until the parameter estimates converge, i.e., the sum of squares of the OC residuals reaches a minimum or the change in the parameter estimates is less than a preset threshold. The parameter estimates are estimated values of the aforementioned navigation solution parameters. It will be appreciated that in each iteration, the OC residual information and partial derivative information are calculated using the current parameter estimates. The normal equation matrix and residual vector are then updated, and the parameter estimates are solved again. When the iteration converges, the parameter estimates are the optimal estimates of the receiver position parameters, receiver clock error parameters, tropospheric delay parameters, and phase ambiguity parameters of the user receiver in the current epoch. The receiver position parameters are the estimated position information of the user receiver.

[0139] In addition, the least squares estimation method can also provide covariance information of the estimated navigation solution parameters, which is used to describe the uncertainty or correlation between the estimated values of each parameter. In the least squares estimation, the covariance information is obtained by inverting the normal equation matrix.

[0140] In some embodiments, for all epochs except the first epoch, before calculating the navigation solution data set corresponding to the epoch, the method further includes:

[0141] Based on the state prediction method of Kalman filtering, the navigation solution data set of the previous epoch is subjected to parameter process noise setting, and the predicted information of the parameters to be estimated at the current epoch is predicted. The predicted information of the parameters to be estimated includes the estimated state of the navigation solution parameters and the covariance information of the navigation solution parameters under the estimated state.

[0142] In this embodiment, for all epochs except the first epoch, before obtaining the navigation solution data set, the state of the current epoch is estimated based on the navigation solution data set of the previous epoch to obtain forecast information of the parameters to be estimated, that is, the state is predicted based on the parameter estimation values of each navigation solution parameter of the previous epoch and the corresponding covariance information, and then the estimated state of the navigation solution parameters of the current epoch is obtained, so that the parameter estimation values of each navigation solution parameter of the previous epoch can be better utilized, thereby improving the estimation accuracy of the parameter estimation values of subsequent epochs and improving positioning accuracy and efficiency.

[0143] In this embodiment, parameter process noise is applied to the navigation solution parameters in the navigation solution dataset of the previous epoch to reflect the randomness of the user receiver's state over time. Different navigation solution parameters have different process noise characteristics. Specifically, the receiver position parameters are treated as white noise, indicating that the user receiver's position is subject to a random, independent error at each epoch. The tropospheric parameters are modeled as random walks, representing the tropospheric parameters. For example, the ZTD parameters have small, random variations between epochs. The carrier phase ambiguity parameters are modeled as constants, indicating that the ambiguity parameters remain constant between epochs. Based on this parameter process noise setting, a Kalman filter uses state transition equations to predict the estimated state of each navigation solution parameter in the current epoch, as well as the covariance information of the navigation solution parameters under the estimated state.

[0144] In this embodiment, for all epochs except the first epoch, the normal equation matrix and residual vector in the estimated state are constructed based on the predicted information of the parameters to be estimated, and the least squares estimation of the navigation solution parameters of the current epoch is performed based on the residual vector and the normal equation matrix, and the navigation solution parameters of the corresponding epoch and the covariance information corresponding to the navigation solution parameters are calculated. In the estimated state, the residual vector is specifically , the corresponding constant matrix is , where the residual vector and constant matrix above are Represents epochs other than the first epoch.

[0145] like Figure 2 As shown, in one embodiment of the present application, the positioning method of the first epoch user receiver specifically includes:

[0146] A1: Calculate the precise orbit parameters of the satellite in the current epoch;

[0147] A2: Calculate satellite precise clock error parameters based on basic navigation broadcast clock error parameters;

[0148] A3: Obtain the OC residual of the dual-frequency observation data and construct the partial derivative information of the dual-frequency observation data;

[0149] A4: Iteratively calculate the estimated position information of the user receiver at the current epoch;

[0150] For subsequent epochs, that is, all epochs except the first epoch, the positioning method of the user receiver includes:

[0151] B1: current epoch state prediction;

[0152] B2: Calculate the precise orbit parameters of the satellite in the current epoch;

[0153] B3: Calculate the satellite precise clock error parameters based on the PPP-B2b clock error correction of the current epoch and the clock error parameter data of the previous epoch;

[0154] B4: Obtain the OC residual of the dual-frequency observation data and construct the partial derivative information of the dual-frequency observation data;

[0155] B5: Iteratively calculate the estimated position information of the user receiver at the current epoch.

[0156] The estimated position information of the user receiver of the current epoch iteratively calculated in step A4 and step B5 is the receiver position parameter in the navigation solution data set of the corresponding epoch calculated in the above step S500.

[0157] See also Figure 3 As shown, the present invention also provides a PPP-B2b precise positioning system with accelerated convergence, the system comprising:

[0158] Satellite precise orbit parameter calculation module 301: used to calculate the precise satellite orbit parameters of each epoch based on the basic navigation message broadcast ephemeris and the precise correction numbers broadcast by PPP-B2b;

[0159] Satellite precise clock error parameter calculation module 302 is used to obtain the corresponding satellite precise clock error parameters for the first epoch based on the basic navigation broadcast clock error parameters. For all epochs except the first epoch, the satellite precise clock error parameters for the current epoch are calculated based on the PPP-B2b clock error correction number of the current epoch and the clock error parameter data of the previous epoch.

[0160] The dual-frequency observation data processing module 303 is used to obtain the OC residual information of the dual-frequency observation data in each epoch and construct the partial derivative information of the dual-frequency observation data with respect to the navigation solution parameters based on the satellite precise orbit parameters and satellite precise clock error parameters using the dual-frequency ionosphere-free combination method for all epochs.

[0161] The navigation solution parameter calculation module 304 is used to construct a normal equation matrix and a residual vector based on the OC residual information and the partial derivative information, and calculate the navigation solution data set of the corresponding epoch based on the normal equation matrix and the residual vector.

[0162] It is understandable that if Figure 1 The contents of the embodiment of the PPP-B2b precise positioning method for accelerating convergence shown in FIG. 1 are applicable to the embodiment of the PPP-B2b precise positioning system for accelerating convergence. The functions specifically implemented by the embodiment of the PPP-B2b precise positioning system for accelerating convergence are similar to those in FIG. Figure 1 The embodiment of the PPP-B2b precise positioning method for accelerating convergence is the same as that shown in FIG. Figure 1The beneficial effects achieved by the embodiment of the PPP-B2b precise positioning method with accelerated convergence are also the same.

[0163] It should be noted that the information interaction, execution process and other contents between the above-mentioned systems are based on the same concept as the embodiment of the method of the present invention. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0164] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0165] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A PPP-B2b precise positioning method with accelerated convergence, characterized in that: include: Calculate the precise satellite orbit parameters for each epoch based on the basic navigation message broadcast ephemeris and the precise corrections broadcast by PPP-B2b; For the first epoch, the corresponding satellite precise clock error parameters are obtained based on the basic navigation broadcast clock error parameters; For all epochs except the first one, the satellite precise clock parameters of the current epoch are calculated based on the PPP-B2b clock correction of the current epoch and the clock parameter data of the previous epoch; For all epochs, based on the satellite's precise orbit parameters and satellite's precise clock parameters, a dual-frequency ionosphere-free combination method is used to obtain the OC residual information of the dual-frequency observation data in each epoch and construct the partial derivative information of the dual-frequency observation data with respect to the navigation solution parameters; Based on the OC residual information and the partial derivative information, a normal equation matrix and a residual vector are constructed, and based on the normal equation matrix and the residual vector, a navigation solution data set of the corresponding epoch is calculated.

2. The method according to claim 1, wherein The calculation of the satellite precise orbit parameters for each epoch based on the basic navigation message broadcast ephemeris and the precise correction numbers broadcast by PPP-B2b includes: Based on the basic navigation message broadcast ephemeris, obtain the satellite orbit position corresponding to each epoch; Obtain orbit corrections broadcast via PPP-B2b and convert them to the satellite orbit coordinate system; Based on the satellite orbit position and the orbit correction number, the precise orbit parameters of the satellite at each epoch are calculated.

3. The method according to claim 1, wherein The clock error parameter data includes satellite precise clock error parameters and clock error correction numbers; For all epochs except the first one, the satellite precise clock parameters for the current epoch are calculated based on the PPP-B2b clock correction of the current epoch and the clock parameter data of the previous epoch, including: Calculate the clock error difference between the current epoch and the previous epoch; Based on the clock error difference and the satellite precise clock error parameters of the previous epoch, the satellite precise clock error parameters of the current epoch are obtained.

4. The method according to claim 1, wherein The dual-frequency observation data includes pseudorange observation data and carrier phase observation data; For all epochs, based on the satellite precise orbit parameters and satellite precise clock parameters, the dual-frequency ionosphere-free combination method is used to obtain the OC residual information of the dual-frequency observation data in each epoch, including: Based on the basic navigation message, the single point positioning processing method is used to calculate the clock error parameters and site coordinates of the user receiver; Calculating a satellite-to-ground distance between the satellite and the user receiver based on the precise satellite orbit parameters and the site coordinates, wherein the site coordinates represent the coordinates of the user receiver; A dual-frequency ionospheric-free combination method is used to perform pseudo-range observations and carrier phase observations on the satellite through the user receiver to obtain pseudo-range observation data and carrier phase observation data. Calculate the correlation errors generated by pseudorange observation and carrier phase observation process; Based on the clock error parameter, the satellite-to-ground distance, the correlation error and the pseudorange observation data, the OC residual information of the pseudorange observation is calculated using a pseudorange residual equation; Based on the clock error parameter, the satellite-to-ground distance, the correlation error and the carrier phase observation data, OC residual information of the carrier phase observation is calculated through a carrier phase residual equation.

5. The method according to claim 4, wherein The method of performing pseudorange observation and carrier phase observation on the satellite by the user receiver to obtain pseudorange observation data and carrier phase observation data includes: The pseudorange observation data is obtained by calculation through the pseudorange observation equation, and the carrier phase observation data is obtained by the carrier phase observation equation; The specific formula of the pseudorange observation equation is: The specific formula of the carrier phase observation equation is: In the pseudorange observation equation and the carrier phase observation equation, The user receiver r represents the satellite s at The pseudo-range observation data of the dual-frequency ionosphere-free combination at the time, The user receiver r represents the satellite s at The carrier phase observation data of the dual-frequency ionospheric-free combination at the time, represents the precise orbit parameters of the satellite, represents the site coordinates of the user receiver, represents the light travel time, represents the speed of light, represents the clock error parameter of the user receiver, represents the satellite precise clock error parameter, represents the tropospheric delay of the satellite-ground line, represents the equivalent wavelength of the dual-frequency ionospheric-free combined phase observation, represents the initial value of the carrier phase ambiguity, represents the correlation error, represents the multipath effect and noise of pseudorange observation data in the dual-frequency ionosphere-free combination, Represents the multipath effect and noise of carrier phase observation data in the dual-frequency ionosphere-free combination.

6. The method according to claim 4, wherein The specific formula of the pseudorange residual equation is: The specific formula of the carrier phase residual equation is: In the pseudorange residual equation and the carrier phase residual equation, represents the OC of the dual-frequency ionospheric-free combination method, Indicates the carrier phase OC in the dual-frequency ionospheric-free combination method, represents pseudorange observation data, represents the carrier phase observation data, represents the precise orbit parameters of the satellite, represents the site coordinates of the user receiver, represents the speed of light, represents the clock error parameter of the user receiver, represents the satellite precise clock error parameter, represents the tropospheric delay of the satellite-ground line, represents the equivalent wavelength of the dual-frequency ionospheric-free combined phase observation, represents the initial value of the carrier phase ambiguity, Represents the correlation error.

7. The method according to claim 4, wherein The navigation solution parameters include receiver position parameters, receiver clock error parameters, tropospheric delay parameters and carrier phase ambiguity parameters; The constructing of partial derivative information of dual-frequency observation data with respect to navigation solution parameters includes: For the partial derivative information of the receiver position parameter, constructing a position partial derivative function of the dual-frequency observation data with respect to the receiver position parameter; For the partial derivative information of the tropospheric delay parameter, constructing a tropospheric partial derivative function of the dual-frequency observation data with respect to the tropospheric delay parameter; For the partial derivative information of the receiver clock error parameter, the speed of light To express; For the partial derivative information of the carrier phase ambiguity parameter, the equivalent wavelength To express.

8. The method according to claim 7, wherein The navigation solution data set includes navigation solution parameters and covariance information of the navigation solution parameters; The constructing a normal equation matrix and a residual vector based on the OC residual information and the partial derivative information, and calculating a navigation solution data set of a corresponding epoch based on the normal equation matrix and the residual vector, includes: Based on the partial derivative information, construct a partial derivative matrix; Constructing a residual vector based on the OC residual information; Constructing a constant matrix based on the partial derivative matrix and the residual vector; Based on the constant matrix, construct a normal equation matrix; Based on the normal equation matrix and the residual vector, a least squares estimation method is used to obtain navigation solution parameters of each epoch and covariance information of the navigation solution parameters.

9. The method according to claim 8, wherein For all epochs except the first epoch, before calculating the navigation solution data set for the corresponding epoch, the following is also included: Based on the state prediction method of Kalman filtering, the navigation solution data set of the previous epoch is subjected to parameter process noise setting, and the predicted information of the parameters to be estimated at the current epoch is predicted. The predicted information of the parameters to be estimated includes the estimated state of the navigation solution parameters and the covariance information of the navigation solution parameters under the estimated state.

10. A PPP-B2b precision positioning system with accelerated convergence, characterized in that: include: Satellite precise orbit parameter calculation module: used to calculate the precise satellite orbit parameters of each epoch based on the basic navigation message broadcast ephemeris and the precise correction numbers broadcast by PPP-B2b; Satellite precise clock error parameter calculation module: used for obtaining the corresponding satellite precise clock error parameters for the first epoch based on the basic navigation broadcast clock error parameters. For all epochs except the first epoch, the satellite precise clock error parameters for the current epoch are calculated based on the PPP-B2b clock error correction number of the current epoch and the clock error parameter data of the previous epoch. Dual-frequency observation data processing module: for all epochs, based on the satellite precise orbit parameters and satellite precise clock error parameters, using the dual-frequency ionosphere-free combination method, obtains the OC residual information of the dual-frequency observation data in each epoch and constructs the partial derivative information of the dual-frequency observation data with respect to the navigation solution parameters; Navigation solution parameter calculation module: used to construct a normal equation matrix and a residual vector based on the OC residual information and the partial derivative information, and calculate the navigation solution data set of the corresponding epoch based on the normal equation matrix and the residual vector.

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