A real-time carrier phase time tracing method and device based on broadcast ephemeris

Abstract

The present invention discloses a real-time carrier phase time tracing method and device based on broadcast ephemeris, including: constructing pseudo-range and carrier phase observation equations of satellites at the observation time; using dual-frequency ionosphere-free combination to obtain ionosphere-free observation equations; obtaining satellite-to-ground distance based on user position and broadcast ephemeris broadcast parameters; screening healthy broadcast ephemeris to obtain information of available satellites; based on all observation equations and information of available satellites, using Kalman filter real-time estimation, using ambiguity as floating point solution, solving epoch by epoch to obtain solution vector of observation time, and obtaining solved user clock error; obtaining GNSSUT information of observation time from broadcast ephemeris; calculating the sum of solved user clock error and GNSSUT information to obtain the difference between UTC and user clock error, so as to realize user and international standard time tracing. The present invention is based on broadcast ephemeris and carrier phase observation values, and users can achieve higher tracing accuracy while being not restricted by the network and location.

Description

Technical Field

[0001] The present invention belongs to the field of time and frequency, and in particular relates to a real-time carrier phase time tracing method and device based on broadcast ephemeris. Background Art

[0002] Accurate and reliable time information is an indispensable component of national defense construction and national economic development, and is a basic element to ensure the normal operation of all industries. GNSS (Global Navigation Satellite System) has become the mainstream way of time transmission with its advantages such as free signals, unlimited users and global coverage, and is widely used in various fields.

[0003] Since 1975, Coordinated Universal Time (UTC) has been recommended by the International Bureau of Weights and Measures as the only international standard time. A unified time reference is the basis for international cooperation and plays a vital role in time accuracy certification, carrier certification and source certification.

[0004] Common view technology and PPP (precise point positioning) technology are the current mainstream traceability methods. The common view method is based on broadcast ephemeris and pseudo-range observations to achieve time traceability. The accuracy of pseudo-range observations restricts the accuracy of time traceability. The PPP method is based on carrier phase observations and broadcast ephemeris and its corrections to achieve time traceability. The corrections of navigation satellites rely on regular broadcasts from the network. When users are in an offline environment, it will affect the continuity of time traceability. In addition, with the current existing technologies, users can only trace back to the coordinated universal time independently maintained by each country, and cannot trace back to the unified coordinated universal time UTC.

[0005] As the accuracy of the broadcast ephemeris of the global satellite navigation system continues to improve, the service performance of the satellite navigation system is also gradually improving. Therefore, how to propose a real-time carrier phase time tracing method based on broadcast ephemeris to overcome the above-mentioned defects of the existing technology and enable users to trace back to the only international standard time is a problem worthy of study. Summary of the invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides a real-time carrier phase time tracing method and device based on broadcast ephemeris. The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a real-time carrier phase time tracing method based on broadcast ephemeris, which is applied to a ground-based GNSS receiver, wherein the GNSS receiver normally receives satellite dual-frequency signals and broadcast ephemeris, and the method includes:

[0008] Under the condition that the user clock error, satellite clock error, tropospheric and ionospheric delays are taken into account and the influence of various error terms is ignored, the pseudo-range observation equation and carrier phase observation equation of each satellite at the observation time are constructed; wherein the various error terms include solid tide, ocean tide, earth rotation correction and phase winding;

[0009] Using a dual-frequency ionospheric elimination combination, the ionospheric elimination observation equations corresponding to the pseudorange observation equation and the carrier phase observation equation are obtained respectively;

[0010] Based on the known user position and the parameters of the broadcast ephemeris, the distance between each satellite and the ground is obtained; by screening healthy broadcast ephemeris, the information of available satellites is obtained, including available satellites and their distance between the satellite and the ground;

[0011] Based on the pseudorange observation equation and the carrier phase observation equation, the corresponding ionospheric elimination observation equations, and the information of the available satellites, a Kalman filter is used to perform real-time estimation, and the ambiguity is used as a floating-point solution to obtain a solution vector of the observation time epoch by epoch, and a solved user clock error is obtained therefrom;

[0012] Obtaining GNSSUT information at the observation time from the acquired broadcast ephemeris;

[0013] By calculating the sum of the solved user clock difference and the GNSSUT information, the difference between the Coordinated Universal Time UTC and the user clock difference is obtained, thereby realizing the traceability of the user and international standard time.

[0014] In a second aspect, an embodiment of the present invention provides a real-time carrier phase time tracing device based on broadcast ephemeris, which is applied to a ground GNSS receiver, wherein the GNSS receiver normally receives satellite dual-frequency signals and broadcast ephemeris, and the device comprises:

[0015] A pseudo-range carrier phase observation equation construction module is used to construct pseudo-range observation equations and carrier phase observation equations for each satellite at the observation time, taking into account user clock error, satellite clock error, tropospheric and ionospheric delays and ignoring the influence of various error terms; wherein the various error terms include solid tide, ocean tide, earth rotation correction and phase entanglement;

[0016] An ionospheric elimination observation equation construction module is used to obtain the ionospheric elimination observation equations corresponding to the pseudorange observation equation and the carrier phase observation equation respectively by using a dual-frequency ionospheric elimination combination;

[0017] The satellite-to-ground distance acquisition module is used to obtain the satellite-to-ground distance of each satellite based on the known user position and the parameters broadcast by the broadcast ephemeris;

[0018] The broadcast ephemeris screening module is used to obtain the information of available satellites, including available satellites and their satellite-to-ground distances, by screening healthy broadcast ephemeris;

[0019] A user clock error solving module is used to use Kalman filtering to perform real-time estimation based on the pseudorange observation equation and the carrier phase observation equation, the corresponding ionospheric elimination observation equations, and the information of the available satellites, and to solve the solution vector of the observation time epoch by epoch using the ambiguity as a floating point solution, and obtain the solved user clock error therefrom;

[0020] A GNSSUT information acquisition module, used to obtain the GNSSUT information of the observation time from the acquired broadcast ephemeris;

[0021] The time tracing module is used to obtain the difference between the coordinated universal time UTC and the user clock difference by calculating the sum of the solved user clock difference and the GNSSUT information, thereby realizing the tracing of the user and international standard time.

[0022] Beneficial effects of the present invention:

[0023] The real-time carrier phase time tracing method based on broadcast ephemeris provided in the embodiment of the present invention is based on broadcast ephemeris and carrier phase observation values. Users are not restricted by the network and location. The carrier phase observation values ​​are two orders of magnitude more accurate than pseudorange observation values, realizing a tracing method with higher accuracy than the traditional common view mode, and can trace in real time and to international standard time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flowchart of a real-time carrier phase time tracing method based on broadcast ephemeris provided in an embodiment of the present invention;

[0025] Figure 2 A schematic diagram for understanding a real-time carrier phase time tracing method based on broadcast ephemeris provided in an embodiment of the present invention;

[0026] Figure 3 A schematic structural diagram of a real-time carrier phase time tracing device based on broadcast ephemeris provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0028] In the first aspect, an embodiment of the present invention provides a real-time carrier phase time tracing method based on broadcast ephemeris, which is applied to a ground-based GNSS receiver. The GNSS receiver normally receives satellite dual-frequency signals and broadcast ephemeris. Please refer to Figure 1 and Figure 2It is understood that the method may include the following steps:

[0029] S1, constructing the pseudorange observation equation and carrier phase observation equation of each satellite at the observation time under the condition of considering the user clock error, satellite clock error, tropospheric and ionospheric delay and ignoring the influence of various error terms; wherein the various error terms include solid tide, ocean tide, earth rotation correction and phase entanglement;

[0030] In the embodiment of the present invention, the GNSS satellite-related data, including the observation values ​​from the GNSS satellite to the user and the broadcast ephemeris from the GNSS satellite to the user, are received by a ground GNSS receiver, i.e., a user receiver. The method of the embodiment of the present invention is implemented on the premise that the GNSS receiver can normally receive the satellite dual-frequency signal and the broadcast ephemeris.

[0031] Specifically, for S1, the pseudorange observation equation and carrier phase observation equation of each satellite at the observation time are expressed as:

[0032] (1);

[0033] in, represents a receiver; Indicates the satellite number; Indicates the observation time; Indicates the observation time ,satellite At frequency Raw pseudorange observations in meters, frequency ; Indicates the observation time ,satellite At frequency The raw phase observations in meters; Indicates satellite The distance between the satellite and the ground, that is, the distance from the station to the satellite The geometric distance of represents the speed of light in a vacuum; Indicates the user clock error, i.e. the receiver clock error; Indicates satellite The satellite clock error is obtained by fitting the three clock error parameters broadcast by the broadcast ephemeris; Indicates satellite Tropospheric delay; Indicates satellite At frequency ionospheric delay; Indicates frequency wavelength; Indicates satellite At frequency Phase observations in cycles; Indicates satellite At frequency The fuzziness of Indicates satellite At frequency The observation noise of the pseudorange observations; Indicates satellite At frequency The observation noise of the phase observation quantity; In the above formula (1), and Through observation, it corresponds to Figure 2 The observation value of GNSS satellite to the user. It is understandable that there are many satellites observed, and for each observation time , each satellite can construct the observation equation shown in the above formula (1).

[0034] S2, using a dual-frequency ionospheric elimination combination, obtaining ionospheric elimination observation equations corresponding to the pseudorange observation equation and the carrier phase observation equation respectively;

[0035] The dual-frequency ionospheric elimination combination can eliminate more than 90% of the ionospheric errors in the signal propagation path. Therefore, by using the dual-frequency ionospheric elimination combination, the ionospheric elimination observation equations corresponding to the pseudorange observation equation and the carrier phase observation equation are obtained as follows:

[0036] (2);

[0037] in, Indicates the observation time ,satellite The ionospheric-free pseudorange observation value; Indicates the observation time ,satellite The deionospheric phase observations of Indicates frequency The frequency of Indicates frequency frequency 1 and frequency 2 are the dual frequencies described in the embodiment of the present invention; Indicates satellite The raw pseudorange observations in meters at frequency point 1; Indicates satellite The raw pseudorange observations in meters at frequency 2; Indicates satellite The raw phase observation in meters at frequency point 1; Indicates satellite The raw phase observation in meters at frequency 2; represents the wavelength of the deionospheric combination; Indicates satellite The ambiguity of the ionospheric elimination combination at frequency 1 and frequency 2; Indicates satellite Observation noise in pseudorange observations of the deionospheric combination; Indicates satellite Observational noise in the phase observables of the deionospheric combination.

[0038] S3, based on the known user position and the parameters broadcast by the broadcast ephemeris, obtain the satellite-to-earth distance of each satellite;

[0039] In the embodiment of the present invention, the user position is unique and known, and the position of each satellite, that is, the satellite orbit, can be obtained through the parameters broadcast by the ephemeris. Therefore, the satellite-to-earth distance of each satellite can be calculated.

[0040] Specifically, based on the known user position and the parameters broadcast by the broadcast ephemeris, the satellite-to-earth distance of each satellite is obtained using the following formula:

[0041] (3);

[0042] in, Indicates satellite The distance between the star and the earth; Indicates the user's location; Indicates the satellite obtained according to the parameters broadcast by the broadcast ephemeris position, i.e. the satellite orbit.

[0043] Among them, satellite Location The six Kepler parameters and six spherical harmonic coefficient parameters broadcast by the broadcast ephemeris are fitted, and the specific process is not described in detail here.

[0044] S4, by screening healthy broadcast ephemeris, obtain the information of available satellites, including available satellites and their satellite-to-ground distances;

[0045] Since anomalies may occur during the generation, uploading and decoding of the broadcast ephemeris, resulting in errors in the calculation of the satellite position and clock difference obtained by fitting the broadcast ephemeris, affecting the time tracing accuracy of the user, the embodiment of the present invention filters the broadcast ephemeris to select healthy broadcast ephemeris, thereby selecting reliable satellites and satellite-to-ground distances for subsequent calculations.

[0046] Specifically, the process of screening healthy broadcast ephemeris includes:

[0047] 1) Discard the unhealthy broadcast ephemeris and complete the first screening;

[0048] 2) Based on the first screening, the broadcast ephemeris with parameters beyond the reasonable range is discarded to complete the second screening;

[0049] The parameters in this step refer to various parameters broadcasted by the broadcast ephemeris. It can be understood that various parameters broadcasted by the broadcast ephemeris have corresponding known reasonable ranges. If a parameter exceeds its reasonable range, the corresponding broadcast ephemeris is discarded.

[0050] 3) Based on the second screening, the satellite orbit and satellite clock error at the current observation time are obtained through the broadcast ephemeris forecast at the previous observation time. When the satellite orbit accuracy and satellite clock error accuracy exceed the threshold, the corresponding satellite is eliminated, thus completing the third screening.

[0051] The satellite orbit and clock error at the current observation time are obtained through the broadcast ephemeris forecast at the previous observation time. Please refer to the relevant technical understanding, which will not be explained in detail here. The satellite orbit represents the satellite position, and the satellite clock error is obtained by fitting the three clock error parameters broadcast by the broadcast ephemeris.

[0052] It can be understood that the accuracy of satellite orbits and satellite clock errors have corresponding thresholds. When the accuracy of either exceeds the corresponding threshold, the corresponding satellite is eliminated to obtain a screened, healthy broadcast ephemeris, based on which the information of available satellites can be obtained. The information of available satellites includes the available satellites and their satellite-to-ground distances for subsequent calculations.

[0053] S5, based on the pseudorange observation equation and the carrier phase observation equation, the corresponding ionospheric observation equations, and the information of the available satellites, a Kalman filter is used to perform real-time estimation, and the ambiguity is used as a floating-point solution to obtain a solution vector of the observation time epoch by epoch, and a solved user clock error is obtained therefrom;

[0054] Specifically, according to the results of formula (1), formula (2), and formula (3) corresponding to the available satellites, Kalman filtering is used for real-time estimation, and the ambiguity is used as a floating-point solution. The solution vector at the observation time is obtained by solving each epoch, which is expressed as:

[0055] (4);

[0056] in, Indicates the observation time The solution vector of ; it can be understood that the sampling interval of the observation value is one second, The result is calculated every second. Indicates the observation time User clock difference; Indicates the observation time The zenith tropospheric wet delay of , and the corresponding dry delay are corrected by the model; is the total number of available satellites; Indicates the time of observation Available satellites The ionospheric ambiguity elimination; Indicates the time of observation Available satellites The ionospheric ambiguity elimination; Indicates transpose.

[0057] Regarding the process of obtaining the solution vector by real-time estimation using Kalman filtering, please refer to the relevant technical understanding and will not be explained here.

[0058] What is actually needed in the embodiment of the present invention is to solve the user clock error in the vector It should be noted that the calculated user clock error is a relative value, which is actually the difference between the actual user clock error and the broadcast ephemeris system time GNSST used.

[0059] S6, obtaining GNSSUT information of the observation time from the acquired broadcast ephemeris;

[0060] The broadcast ephemeris in this step is recorded as the filtered broadcast ephemeris. GNSSUT information can be GPUT (difference between GPS and UTC), GAUT (difference between Galileo and UTC), BDUT (difference between BDS and UTC), etc. GNSSUT information is actually the difference between Coordinated Universal Time UTC and Broadcast Ephemeris System Time GNSST.

[0061] Specifically, S6 is expressed as:

[0062] (5);

[0063] in, GNSSUT information representing the observation time; Indicates multiplication; Indicates the start time of broadcast ephemeris, which is broadcast once a day; and Represents the coefficient of broadcast ephemeris. Using formula (5), the predicted arrival and user clock error Moments of consistency.

[0064] S7, by calculating the sum of the solved user clock difference and the GNSSUT information, the difference between the Coordinated Universal Time UTC and the user clock difference is obtained, thereby realizing the traceability of the user and international standard time.

[0065] The principle of obtaining the difference between the Coordinated Universal Time UTC and the user clock difference by calculating the sum of the solved user clock difference and the GNSSUT information is expressed as follows:

[0066] (6);

[0067] in, is Coordinated Universal Time; is the GNSSUT information at the observation time; is the calculated user clock error, indicating the difference between the actual user clock error and the broadcast ephemeris system time GNSST used.

[0068] From formula (6), we can see that after expanding the brackets on the right side of the equal sign, the result is The embodiment of the present invention is based on the physical meanings and calculation expressions corresponding to the two items, the GNSSUT information at the observation time and the calculated user clock difference. Without obtaining the specific values ​​of each item, the embodiment of the present invention simply uses the obtained GNSSUT information and the calculated user clock difference, and cleverly uses the mathematical relationship between the physical quantities of the two to simply calculate the difference between the Coordinated Universal Time UTC and the user clock difference. , realizing real-time traceability of users and international standard time.

[0069] The real-time carrier phase time tracing method based on broadcast ephemeris provided in the embodiment of the present invention is based on broadcast ephemeris and carrier phase observation values, and the user is not restricted by the network and location, thus realizing a tracing method with higher accuracy than the traditional common view mode. The common view mode only uses pseudo-range observation values, and the carrier phase observation values ​​are two orders of magnitude more accurate than the pseudo-range observation values, and can be traced in real time to the international standard time.

[0070] In the second aspect, corresponding to the above method embodiment, the embodiment of the present invention further provides a real-time carrier phase time tracing device based on broadcast ephemeris, which is applied to a ground-based GNSS receiver, and the GNSS receiver normally receives satellite dual-frequency signals and broadcast ephemeris, such as Figure 3 As shown, the device comprises:

[0071] A pseudo-range carrier phase observation equation construction module is used to construct pseudo-range observation equations and carrier phase observation equations for each satellite at the observation time, taking into account user clock error, satellite clock error, tropospheric and ionospheric delays and ignoring the influence of various error terms; wherein the various error terms include solid tide, ocean tide, earth rotation correction and phase entanglement;

[0072] An ionospheric elimination observation equation construction module is used to obtain the ionospheric elimination observation equations corresponding to the pseudorange observation equation and the carrier phase observation equation respectively by using a dual-frequency ionospheric elimination combination;

[0073] The satellite-to-ground distance acquisition module is used to obtain the satellite-to-ground distance of each satellite based on the known user position and the parameters broadcast by the broadcast ephemeris;

[0074] The broadcast ephemeris screening module is used to obtain the information of available satellites, including available satellites and their satellite-to-ground distances, by screening healthy broadcast ephemeris;

[0075] A user clock error solving module is used to use Kalman filtering to perform real-time estimation based on the pseudorange observation equation and the carrier phase observation equation, the corresponding ionospheric elimination observation equations, and the information of the available satellites, and to solve the solution vector of the observation time epoch by epoch using the ambiguity as a floating point solution, and obtain the solved user clock error therefrom;

[0076] A GNSSUT information acquisition module, used to obtain the GNSSUT information of the observation time from the acquired broadcast ephemeris;

[0077] The time tracing module is used to obtain the difference between the coordinated universal time UTC and the user clock difference by calculating the sum of the solved user clock difference and the GNSSUT information, thereby realizing the tracing of the user and international standard time.

[0078] For the specific processing process and related effects of each module of the device, please refer to the relevant content of the first aspect and will not be repeated here.

[0079] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A real-time carrier phase time tracing method based on broadcast ephemeris, characterized in that: A GNSS receiver applied to the ground, the GNSS receiver normally receives satellite dual-frequency signals and broadcast ephemeris, and the method comprises: Under the condition that the user clock error, satellite clock error, tropospheric and ionospheric delays are taken into account and the influence of various error terms is ignored, the pseudo-range observation equation and carrier phase observation equation of each satellite at the observation time are constructed; wherein the various error terms include solid tide, ocean tide, earth rotation correction and phase winding; Using a dual-frequency ionospheric elimination combination, the ionospheric elimination observation equations corresponding to the pseudorange observation equation and the carrier phase observation equation are obtained respectively; Based on the known user position and the parameters broadcast by the broadcast ephemeris, the distance between each satellite and the ground is obtained; By screening healthy broadcast ephemeris, information about available satellites is obtained, including available satellites and their distances from the satellite to the ground; Based on the pseudorange observation equation and the carrier phase observation equation, the corresponding ionospheric elimination observation equations, and the information of the available satellites, a Kalman filter is used to perform real-time estimation, and the ambiguity is used as a floating-point solution to obtain a solution vector of the observation time epoch by epoch, and a solved user clock error is obtained therefrom; Obtaining GNSSUT information at the observation time from the acquired broadcast ephemeris; By calculating the sum of the solved user clock difference and the GNSSUT information, the difference between the Coordinated Universal Time UTC and the user clock difference is obtained, thereby realizing the traceability of the user and international standard time.

2. The real-time carrier phase time tracing method based on broadcast ephemeris according to claim 1 is characterized in that: The pseudo-range observation equation and carrier phase observation equation of each satellite at the observation time are expressed as: ； in, represents a receiver; Indicates the satellite number; Indicates the observation time; Indicates the observation time ,satellite At frequency Raw pseudorange observations in meters, frequency ; Indicates the observation time ,satellite At frequency The raw phase observations in meters; Indicates satellite The distance between the star and the earth; represents the speed of light in a vacuum; Indicates the user clock difference; Indicates satellite The satellite clock error is obtained by fitting the three clock error parameters broadcast by the broadcast ephemeris; Indicates satellite Tropospheric delay; Indicates satellite At frequency ionospheric delay; Indicates frequency wavelength; Indicates satellite At frequency Phase observations in cycles; Indicates satellite At frequency The fuzziness of Indicates satellite At frequency The observation noise of the pseudorange observations; Indicates satellite At frequency The observation noise of the phase observation.

3. The real-time carrier phase time tracing method based on broadcast ephemeris according to claim 2 is characterized in that: The deionospheric observation equations corresponding to the pseudorange observation equation and the carrier phase observation equation are expressed as: ； in, Indicates the observation time ,satellite The ionospheric-free pseudorange observation value; Indicates the observation time ,satellite The deionospheric phase observations of Indicates frequency The frequency of Indicates frequency The frequency of Indicates satellite The raw pseudorange observations in meters at frequency point 1; Indicates satellite The raw pseudorange observations in meters at frequency 2; Indicates satellite The raw phase observation in meters at frequency point 1; Indicates satellite The raw phase observation in meters at frequency 2; represents the wavelength of the deionospheric combination; Indicates satellite The ambiguity of the ionospheric elimination combination at frequency 1 and frequency 2; Indicates satellite Observation noise in pseudorange observations of the deionospheric combination; Indicates satellite Observational noise in the phase observables of the deionospheric combination.

4. The real-time carrier phase time tracing method based on broadcast ephemeris according to claim 1 is characterized in that: Based on the known user position and the parameters broadcast by the broadcast ephemeris, the distance between each satellite and the ground is obtained using the following formula: ； in, Indicates satellite The distance between the star and the earth; Indicates the user's location; Indicates the satellite obtained according to the parameters broadcast by the broadcast ephemeris location.

5. The real-time carrier phase time tracing method based on broadcast ephemeris according to claim 4 is characterized in that: satellite Location It is obtained by fitting the 6 Kepler parameters and 6 spherical harmonic coefficients parameters broadcast by the broadcast ephemeris.

6. The real-time carrier phase time tracing method based on broadcast ephemeris according to claim 4 is characterized in that: The process of screening for healthy broadcast ephemeris includes: Discard the broadcast ephemeris marked as unhealthy and complete the first screening; Based on the first screening, the broadcast ephemeris with parameters beyond the reasonable range is discarded to complete the second screening; Based on the second screening, the satellite orbit and satellite clock error at the current observation time are obtained through the broadcast ephemeris forecast at the previous observation time. When the satellite orbit accuracy and satellite clock error accuracy exceed the threshold, the corresponding satellite is eliminated, thus completing the third screening.

7. The real-time carrier phase time tracing method based on broadcast ephemeris according to claim 6 is characterized in that: The solution vector at the observation time is expressed as: ； in, Indicates the observation time The solution vector of ; Indicates the observation time User clock difference; Indicates the observation time The zenith tropospheric wet delay of , and the corresponding dry delay are corrected by the model; is the total number of available satellites; Indicates the time of observation Available satellites The ionospheric ambiguity elimination; Indicates the time of observation Available satellites The ionospheric ambiguity elimination; Indicates transpose.

8. The real-time carrier phase time tracing method based on broadcast ephemeris according to claim 7 is characterized in that: The GNSSUT information at the observation time is obtained from the acquired broadcast ephemeris and is expressed as follows: ； in, The GNSSUT information representing the observation time is essentially the difference between the Coordinated Universal Time UTC and the Broadcast Ephemeris System Time GNSST; Indicates multiplication; Indicates the start time of broadcast ephemeris, which is broadcast once a day; and Indicates the coefficients of the broadcast ephemeris.

9. The real-time carrier phase time tracing method based on broadcast ephemeris according to claim 8, characterized in that: The principle of obtaining the difference between the Coordinated Universal Time UTC and the user clock difference by calculating the sum of the solved user clock difference and the GNSSUT information is expressed as follows: ； in, is Coordinated Universal Time; is the GNSSUT information at the observation time; is the calculated user clock error, indicating the difference between the actual user clock error and the used broadcast ephemeris system time GNSST.

10. A real-time carrier phase time tracing device based on broadcast ephemeris, characterized in that: A GNSS receiver applied to the ground, the GNSS receiver normally receives satellite dual-frequency signals and broadcast ephemeris, and the device comprises: A pseudo-range carrier phase observation equation construction module is used to construct pseudo-range observation equations and carrier phase observation equations for each satellite at the observation time, taking into account user clock error, satellite clock error, tropospheric and ionospheric delays and ignoring the influence of various error terms; wherein the various error terms include solid tide, ocean tide, earth rotation correction and phase entanglement; An ionospheric elimination observation equation construction module is used to obtain the ionospheric elimination observation equations corresponding to the pseudorange observation equation and the carrier phase observation equation respectively by using a dual-frequency ionospheric elimination combination; The satellite-to-ground distance acquisition module is used to obtain the satellite-to-ground distance of each satellite based on the known user position and the parameters broadcast by the broadcast ephemeris; The broadcast ephemeris screening module is used to obtain the information of available satellites, including available satellites and their satellite-to-ground distances, by screening healthy broadcast ephemeris; A user clock error solving module is used to use Kalman filtering to perform real-time estimation based on the pseudorange observation equation and the carrier phase observation equation, the corresponding ionospheric elimination observation equations, and the information of the available satellites, and to solve the solution vector of the observation time epoch by epoch using the ambiguity as a floating point solution, and obtain the solved user clock error therefrom; A GNSSUT information acquisition module, used to obtain the GNSSUT information of the observation time from the acquired broadcast ephemeris; The time tracing module is used to obtain the difference between the coordinated universal time UTC and the user clock difference by calculating the sum of the solved user clock difference and the GNSSUT information, thereby realizing the tracing of the user and international standard time.

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