Ground PNT system high-precision positioning method based on carrier phase observation value
Patent Information
- Application Number
- CN202511280455.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-09
- Publication Date
- 2025-11-14
AI Technical Summary
但目前关于如何提高地面PNT系统定位精度的研究还较为空白，因此亟需一种仅针对地面PNT系统来提高定位精度的方法
[0016]其有益效果在于：本发明公开了一种基于载波相位观测值的地面PNT系统高精度定位方法，通过码相位技术得到测量伪距，并结合载波波长，得到载波相位的整周模糊度浮点解；依据伪距测量误差，确定整周模糊度的搜索区间；在所述搜索区间内遍历整周模糊度整数解组合，将其与载波相位观测值小数部分结合后与载波波长相乘，得到载波相位观测伪距；获取所有基站坐标及相应载波相位观测伪距，构建多个定位方程组并进行解算，筛选定位残差最小的组合作为定位结果输出。本发明无需依赖差分站的配合、多频信号辅助以及载波相位误差协方差矩阵计算，就能针对地面PNT系统实现厘米级甚至毫米级的高精度定位。
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Figure CN120949281A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of satellite navigation technology, and in particular to a high-precision positioning method for a ground-based PNT system based on carrier phase observations. Background Technology
[0002] Since the beginning of the 21st century, satellite navigation has become deeply integrated into people's daily lives, from smart terminal positioning to professional applications in various industries, and the demand for high-precision positioning has grown exponentially. Against this backdrop, pseudosatellite navigation, with its outstanding advantage of flexible deployment, has become a key supplementary means to expand the application scenarios of high-precision positioning. It can help achieve high-precision carrier phase positioning, providing new technical support for fields with stringent positioning accuracy requirements such as surveying and mapping remote sensing, autonomous driving, and disaster monitoring.
[0003] In research on carrier phase positioning, most studies are based on satellite positioning. Specifically, differential observation or multi-frequency signal assistance is needed to improve positioning accuracy. The principle of differential observation is to use a base station (differential station) with a known location to calculate and broadcast error correction. Assuming that the user and the base station receive signals from the same satellite, since the precise location of the base station is known, the error between the actual measurement value and the theoretical value can be calculated and broadcast to the user. The user can then correct their own measurement value according to the calibration, thereby eliminating most of the common error. The principle of multi-frequency signal assistance is that multi-frequency GPS can use signals of multiple frequencies simultaneously. Different frequency signals are affected by atmospheric delay and other errors differently. By processing and combining different frequency signals, the influence of signal propagation errors can be effectively reduced, thereby improving positioning accuracy.
[0004] Ground-based PNT systems are the core collective term for ground-based wireless navigation systems. Their principle involves fixed ground base stations transmitting radio signals, which users then receive and calculate their location. However, current research on how to improve the positioning accuracy of ground-based PNT systems is relatively lacking. Therefore, there is an urgent need for a method specifically designed to improve the positioning accuracy of ground-based PNT systems. Summary of the Invention
[0005] In view of this, this application provides a high-precision positioning method for a ground-based PNT system based on carrier phase observations to address the shortcomings of existing technologies.
[0006] The first aspect of this application provides a high-precision positioning method for a ground-based PNT system based on carrier phase observations, comprising: Based on code phase technology, the measurement pseudorange of multiple base stations is obtained, and combined with the carrier wavelength, the integer ambiguity floating-point solution of the corresponding carrier phase is obtained. The integer ambiguity floating-point solution is rounded to obtain the rounding result. Based on the pseudo-moment measurement error, the search interval of the integer ambiguity is determined with the rounding result as the central reference. Within the search interval, all existing integer solutions with integer ambiguity are obtained; For each set of integer ambiguity solutions, the fractional part of the corresponding carrier phase observation value is combined with the carrier wavelength to obtain multiple carrier phase observation pseudo-moments for each base station. The pseudorange of all carrier phase observations from each base station is distributed into different datasets to obtain multiple datasets; Based on the base station coordinates of all base stations and all data sets, multiple nonlinear positioning equations are constructed. Solve all nonlinear positioning equations, select the integer solution with the smallest carrier phase positioning residual as the optimal fixed integer ambiguity solution, and output the receiver's three-dimensional coordinates and receiver clock error under the corresponding nonlinear positioning equations.
[0007] In one possible implementation of the first aspect, obtaining the measurement pseudorange of multiple base stations based on code phase technology includes: To measure pseudorange, The signal propagation time between the base station and the receiver. To measure the phase difference between the received pseudo-random code and the local reference pseudo-random code at the receiver. The width of the symbol. It is at the speed of light.
[0008] In one possible implementation of the first aspect, the integer ambiguity floating-point solution for the corresponding carrier phase, in conjunction with the carrier wavelength, includes: For the integer ambiguity floating-point solution of the carrier phase, The carrier wavelength.
[0009] In one possible implementation of the first aspect, determining the search interval for integer ambiguity based on the rounding result as a central reference, according to the pseudo-moment measurement error, includes: Based on the pseudorange measurement error, the search range for integer ambiguity is determined; The search interval is determined by using the rounding result as the central reference of the search range.
[0010] In one possible implementation of the first aspect, the pseudorange measurement error includes hardware prior error and pseudorange measurement error, wherein the pseudorange measurement error is obtained by deploying calibration receivers at multiple calibration points for the ground PNT system.
[0011] In one possible implementation of the first aspect, obtaining multiple carrier phase observation pseudo-moments for each base station includes: For carrier phase observation pseudorange, The fractional part of the carrier phase observation. For integer solutions of the integer ambiguity of the carrier phase.
[0012] One possible implementation of the first aspect also includes: The receiver obtains the fractional part of the corresponding carrier phase observation value by measuring the phase difference between the received signal phase and the local reference phase.
[0013] In one possible implementation of the first aspect, constructing a system of multiple nonlinear positioning equations includes: For the receiver's three-dimensional coordinates, The base station coordinates are the base station coordinates. For the number of base stations, For receiver clock difference, For carrier phase observation pseudorange, Each item belongs to a different dataset.
[0014] In one possible implementation of the first aspect, the Levenberg-Marquardt algorithm is used to solve all the nonlinear positioning equations.
[0015] In one possible implementation of the first aspect, the total number of base stations is at least four.
[0016] Its beneficial effects are as follows: This invention discloses a high-precision positioning method for ground-based PNT systems based on carrier phase observations. It obtains the measured pseudorange through code phase technology and, combined with the carrier wavelength, obtains the integer ambiguity floating-point solution of the carrier phase. Based on the pseudorange measurement error, a search interval for the integer ambiguity is determined. Within the search interval, the integer solutions of the integer ambiguity are traversed, and after combining them with the fractional part of the carrier phase observation value, they are multiplied by the carrier wavelength to obtain the carrier phase observation pseudorange. All base station coordinates and corresponding carrier phase observation pseudoranges are obtained, multiple positioning equation sets are constructed and solved, and the combination with the smallest positioning residual is selected as the positioning result output. This invention achieves centimeter-level or even millimeter-level high-precision positioning for ground-based PNT systems without relying on differential station cooperation, multi-frequency signal assistance, or carrier phase error covariance matrix calculation. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of a high-precision positioning equation for a ground-based PNT system based on carrier phase observations, provided in an embodiment of this application. Figure 2 This is a schematic diagram of the composition of a ground-based PNT system provided in an embodiment of this application; Figure 3 This is a first printed image of the simulation positioning result of a ground PNT system provided in an embodiment of this application; Figure 4 This is a second printed image of the simulation positioning result of a ground PNT system provided in an embodiment of this application. Detailed Implementation
[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0020] In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.
[0021] Example Current research on improving satellite positioning accuracy primarily utilizes carrier phase positioning, often relying on differential observation or multi-frequency signal assistance. However, both differential observation and multi-frequency signal assistance share a common problem: they are ill-suited for scenarios lacking infrastructure, with strong signal blockage, and requiring low costs. In situations such as indoor positioning, emergency rescue, and consumer-grade devices, differential observation is unusable due to the lack of reference stations and communication links, while multi-frequency signals are ineffective due to high hardware costs and signal blockage, hindering the implementation of high-precision positioning.
[0022] However, research on how to improve the positioning accuracy of ground-based PNT systems is still relatively lacking. Furthermore, research on carrier phase in satellite positioning cannot be directly applied to ground-based PNT systems, as they belong to different positioning systems. Therefore, research on how to improve the positioning accuracy of ground-based PNT systems is of great practical significance and application value.
[0023] Therefore, this application provides a high-precision positioning method for a ground-based PNT system based on carrier phase observations, such as... Figure 1 As shown, it includes: Based on code phase technology, the measurement pseudorange of multiple base stations is obtained, and combined with the carrier wavelength, the integer ambiguity floating-point solution of the corresponding carrier phase is obtained. The integer ambiguity floating-point solution is rounded to obtain the rounding result. Based on the pseudo-moment measurement error, the search interval of the integer ambiguity is determined with the rounding result as the central reference. Within the search interval, all existing integer solutions with integer ambiguity are obtained; For each set of integer ambiguity solutions, the fractional part of the corresponding carrier phase observation value is combined with the carrier wavelength to obtain multiple carrier phase observation pseudo-moments for each base station. The pseudorange of all carrier phase observations from each base station is distributed into different datasets to obtain multiple datasets; Based on the base station coordinates of all base stations and all data sets, multiple nonlinear positioning equations are constructed. Solve all nonlinear positioning equations, select the integer solution with the smallest carrier phase positioning residual as the optimal fixed integer ambiguity solution, and output the receiver's three-dimensional coordinates and receiver clock error under the corresponding nonlinear positioning equations.
[0024] Before explaining the implementation principle of this embodiment, the following explains how existing ground-based PNT systems achieve positioning: The positioning principle of ground-based PNT systems is based on the distance formula between two points: in, Indicates the coordinates of the ground-based PNT system base station. For the receiver's three-dimensional coordinates, This represents the distance between the receiver and the base station. In a ground-based PNT positioning system, the base station coordinates are known quantities, while... An approximation can be made using pseudorange observations (measuring pseudorange). Pseudorange observations are the most fundamental observations in a ground-based positioning system. They are obtained by multiplying the propagation time of the signal from the base station to the receiver by the speed of light. The observation equation is similar to that used in the pseudorange measurement example, specifically: in, Receiver observation of reception time Includes a fixed receiver clock difference (Right now ); Therefore, the above equation can be iterated to the following formula: In this method, the receiver measures signal propagation time using pseudo-random code phase offset. However, the pseudo-random code has a large symbol width, and the receiver's measurement accuracy for code phase is typically only 0.1 chip widths, resulting in a distance error on the order of ten meters (even after optimization, it can only reach the meter level), which cannot meet the high-precision requirements of surveying and mapping. In contrast, carrier phase observations are based on carrier signal phase difference measurements. By solving integer ambiguity and geometric distance, centimeter-level or even millimeter-level accuracy can be achieved. The principle is to utilize the fixed characteristic of the carrier wavelength, calculating the precise distance by determining the integer number of signal propagation cycles and the phase offset value of less than one cycle. However, solving for fixed integer ambiguity is very difficult. Traditional methods, such as the LAMBDA algorithm, require a floating-point solution for the carrier phase observations and the observation error covariance matrix (reflecting the correlation between observations). The optimal integer solution for integer ambiguity is searched using integer least squares estimation, and then the integer ambiguity and carrier phase observations are combined to obtain the distance between the base station and the receiver for carrier phase positioning calculation. It should be noted that the above formula is also the underlying logic for constructing the nonlinear positioning equation set in this embodiment.
[0025] This embodiment differs from traditional carrier phase positioning methods in that it does not require the cooperation of differential stations (reference stations with known coordinates), multi-frequency signal assistance, or carrier phase error covariance matrix calculation. It only requires adding an integer ambiguity traversal search process to the traditional carrier phase positioning method, recording the corresponding positioning error residuals, and selecting the positioning result corresponding to the minimum positioning error residual as the output. This achieves high-precision carrier phase positioning. The specific implementation logic is as follows: Step 1: The terrestrial PNT system contains at least 4 base stations. The pseudorange measurements of all base stations are obtained using code phase technology, including: ; and combined with the carrier wavelength, the integer ambiguity floating-point solution for the corresponding carrier phase is obtained, including: It should be noted that the integer ambiguity floating-point solution of the carrier phase includes parameters such as the integer part, the fractional part, and the receiver clock difference.
[0026] Step 2: Based on the pseudorange measurement error, set the search range of integer solutions for the integer ambiguity floating-point solution of each base station. When setting the search range, it is necessary to balance the relationship between the actual coverage value and the control computation. The pseudorange measurement error integrates the hardware prior error and the pseudorange measured error (including multipath effect, scene clock drift, etc.). The hardware prior error includes hardware noise, fixed delay and manufacturer specification, while the pseudorange measured error is determined by setting a calibration point for actual measurement. It should be noted that the pseudorange measurement error applies to the entire PNT system, so it is consistent for all base stations.
[0027] Regarding the determination of the search range, the pseudorange measurement error (the ratio of pseudorange measurement error to carrier wavelength) is first converted into integer ambiguity error. A conservative value is then used to set the search range for the integer ambiguity error. For example, the integer result of the floating-point solution of the integer ambiguity is used as the central reference, and the range is extended upwards and downwards by 5 integer cycles to ensure coverage of the true integer part, such as base station 1. The value is approximately 39000.5, and the search range is 38995~39005 (5 whole cycles, totaling 11 integer solutions). All base stations have the same search interval size, meaning the number of integer solutions is the same, ensuring the synchronization of subsequent whole-cycle combination traversals. The above data is for illustrative purposes only and can be adjusted according to actual conditions; this embodiment does not impose specific limitations.
[0028] Step 3: For each set of integer ambiguity solutions, combine the fractional part of the carrier phase with the carrier wavelength to obtain the carrier phase observation pseudorange used for positioning, including: The fractional part of the carrier phase observation is obtained by measuring the phase difference between the received signal phase and the local reference phase using the receiver, and extracting the portion of the phase difference that is less than an integer cycle.
[0029] This embodiment sets up data sets, placing all carrier phase observation pseudoranges from each base station into different data sets. Based on the principle of synchronous traversal, it selects one carrier phase observation pseudorange from each data set for combination, providing observation values for subsequent equations. It should be noted that each data set corresponds one-to-one with a base station.
[0030] Step 4: Based on the coordinates of all base stations and the carrier phase observation pseudorange stored in all datasets, construct a set of multiple nonlinear positioning equations containing the receiver's parameters to be estimated (including the receiver's three-dimensional coordinates and clock bias), including: Regarding the construction logic of the equation system, the left side is the theoretical pseudorange calculated based on the parameters to be estimated, while the right side is the generated carrier phase observation pseudorange. Since it involves square root operations, it cannot be solved linearly directly and requires iterative calculation.
[0031] Step 5: The Levenberg-Marquardt algorithm is used to iteratively solve the nonlinear positioning equations. Since each positioning equation contains parameters to be estimated, which are the receiver's three-dimensional coordinates... and clock difference There are four unknowns, therefore at least four equations are needed to solve this problem, meaning the number of base stations must be at least four. Let... Indicates the receiver position and clock difference. This represents the combination of observation pseudoranges, therefore the above system of equations can be abstracted into a system of observation equations. The Levenberg-Marquardt algorithm is then used to solve the observation equations. The solution steps mainly include: The first step is to set the initial values of the parameters to be estimated. , Indicates the receiver coordinates. This represents the receiver clock bias, for nonlinear observation equations. According to the initial value Calculate the Jacobian matrix The elements of the Jacobian matrix can be represented as: in, Indicates the number of observation equations. This indicates the number of parameters to be estimated, including four parameters: receiver three-dimensional coordinates and clock error. The second step is to construct a system containing damping factors. Regularization equation The residuals of the parameters to be estimated are solved by adjusting the damping factor, a hyperparameter, to balance the characteristics of the Gauss-Newton method and the fastest descent method. The third step is to update the estimated parameter values based on the parameter residuals, i.e. ,in This indicates the number of iterations; after updating the parameters, the objective function value is recalculated. Compared to the Jacobian matrix; The fourth step is to determine whether the iteration has converged and set a convergence threshold. ,if If the parameter residual is less than the set threshold or the maximum number of iterations is reached, the iteration is terminated and the final parameter estimate is output; otherwise, the iteration returns to the second step.
[0032] Step 6: Select the integer ambiguity solution corresponding to the minimum carrier phase positioning residual as the optimal fixed integer ambiguity solution, and output the receiver's three-dimensional coordinates and receiver clock error under the corresponding nonlinear positioning equation set. It should be noted that the above steps are only for clarity in explaining the implementation details of this embodiment and have no other limiting effect.
[0033] Please refer to Figure 2 A ground-based PNT system comprising seven pseudosatellites was constructed. This embodiment adds an iterative integer ambiguity solution process to the positioning solution. Different ambiguity combinations are combined with carrier phase observations to obtain carrier phase pseudorange for positioning calculation. Then, based on the magnitude of the carrier phase positioning residual, it is determined whether the fixed integer ambiguity is optimal. The integer solution with the smallest carrier phase positioning residual is selected as the optimal fixed integer ambiguity solution, ultimately obtaining high-precision carrier phase positioning results. Please refer to [reference needed]. Figure 3 and Figure 4 The simulation results of positioning using carrier phase positioning residual and pseudorange positioning residual in this embodiment show that the carrier phase positioning residual can achieve centimeter-level positioning effect, meet the requirements of high-precision positioning, and does not require the cooperation of differential stations, multi-frequency signal assistance, or carrier phase error covariance matrix calculation.
[0034] In some embodiments, obtaining the measurement pseudorange of multiple base stations based on code phase technology includes: To measure pseudorange, The signal propagation time between the base station and the receiver. To measure the phase difference between the received pseudo-random code and the local reference pseudo-random code at the receiver. The width of the symbol. It is the speed of light.
[0035] In some embodiments, obtaining the integer ambiguity floating-point solution for the corresponding carrier phase, in conjunction with the carrier wavelength, includes: For the integer ambiguity floating-point solution of the carrier phase, The carrier wavelength.
[0036] In some embodiments, determining the search interval for integer ambiguity based on the rounding result as the central reference, based on the pseudo-moment measurement error, includes: Based on the pseudorange measurement error, the search range for integer ambiguity is determined; The search interval is determined by using the rounding result as the central reference of the search range.
[0037] In some embodiments, the pseudorange measurement error includes hardware prior error and pseudorange measured error. The pseudorange measured error is for the ground PNT system and is measured and obtained by deploying calibration receivers at multiple calibration points.
[0038] In some embodiments, obtaining multiple carrier phase observation pseudo-moments for each base station includes: For carrier phase observation pseudorange, The fractional part of the carrier phase observation. For integer solutions of the integer ambiguity of the carrier phase.
[0039] In some embodiments, it also includes: The receiver obtains the fractional part of the corresponding carrier phase observation value by measuring the phase difference between the received signal phase and the local reference phase.
[0040] In some embodiments, constructing a set of multiple nonlinear positioning equations includes: For the receiver's three-dimensional coordinates, The base station coordinates are the base station coordinates. For the number of base stations, For receiver clock difference, For carrier phase observation pseudorange, Each item belongs to a different dataset.
[0041] In some embodiments, the Levenberg-Marquardt algorithm is used to solve all nonlinear positioning equations.
[0042] In some embodiments, the number of all base stations is at least four.
[0043] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computing software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
[0044] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0045] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A high-precision positioning method for a ground-based PNT system based on carrier phase observations, wherein the ground-based PNT system comprises multiple base stations, characterized in that, include: Based on code phase technology, the measurement pseudorange of multiple base stations is obtained, and combined with the carrier wavelength, the integer ambiguity floating-point solution of the corresponding carrier phase is obtained. The integer ambiguity floating-point solution is rounded to obtain the rounding result. Based on the pseudo-moment measurement error, the search interval of the integer ambiguity is determined with the rounding result as the central reference. Within the search interval, all existing integer solutions with integer ambiguity are obtained; For each set of integer ambiguity solutions, the fractional part of the corresponding carrier phase observation value is combined with the carrier wavelength to obtain multiple carrier phase observation pseudo-moments for each base station. The pseudorange of all carrier phase observations from each base station is distributed into different datasets to obtain multiple datasets; Based on the base station coordinates of all base stations and all data sets, multiple nonlinear positioning equations are constructed. Solve all nonlinear positioning equations, select the integer solution with the smallest carrier phase positioning residual as the optimal fixed integer ambiguity solution, and output the receiver's three-dimensional coordinates and receiver clock error under the corresponding nonlinear positioning equations.
2. The high-precision positioning method for a ground-based PNT system based on carrier phase observations according to claim 1, characterized in that, The pseudorange measurements obtained from multiple base stations based on code phase technology include: To measure pseudorange, The signal propagation time between the base station and the receiver. To measure the phase difference between the received pseudo-random code and the local reference pseudo-random code at the receiver. The width of the symbol. It is the speed of light.
3. The high-precision positioning method for a ground-based PNT system based on carrier phase observations according to claim 2, characterized in that, Combining the carrier wavelength, the integer ambiguity floating-point solution for the corresponding carrier phase includes: For the integer ambiguity floating-point solution of the carrier phase, The carrier wavelength.
4. The high-precision positioning method for a ground-based PNT system based on carrier phase observations according to claim 1, characterized in that, Based on the pseudo-moment measurement error, the search interval for integer ambiguity is determined using the rounding result as the central reference, including: Based on the pseudorange measurement error, the search range for integer ambiguity is determined; The search interval is determined by using the rounding result as the central reference of the search range.
5. A high-precision positioning method for a ground-based PNT system based on carrier phase observations according to claim 4, characterized in that, The pseudorange measurement error includes hardware prior error and pseudorange measured error. The pseudorange measured error is for the ground PNT system and is obtained by deploying verification receivers at multiple verification points.
6. A high-precision positioning method for a ground-based PNT system based on carrier phase observations according to claim 1, characterized in that, The multiple carrier phase observation pseudo-moments obtained for each base station include: For carrier phase observation pseudorange, The fractional part of the carrier phase observation. For integer solutions of the integer ambiguity of the carrier phase.
7. A high-precision positioning method for a ground-based PNT system based on carrier phase observations according to claim 6, characterized in that, Also includes: The receiver obtains the fractional part of the corresponding carrier phase observation value by measuring the phase difference between the received signal phase and the local reference phase.
8. A high-precision positioning method for a ground-based PNT system based on carrier phase observations according to claim 6, characterized in that, The construction of multiple nonlinear localization equations includes: For the receiver's three-dimensional coordinates, The base station coordinates are the base station coordinates. For the number of base stations, For receiver clock difference, For carrier phase observation pseudorange, Each item belongs to a different dataset.
9. A high-precision positioning method for a ground-based PNT system based on carrier phase observations according to claim 1, characterized in that, The Levenberg-Marquardt algorithm was used to solve all the nonlinear positioning equations.
10. A high-precision positioning method for a ground-based PNT system based on carrier phase observations according to claim 1, characterized in that, The total number of base stations must be at least 4.