CN114286286A

CN114286286A - Time synchronization method, apparatus, medium, and program product

Info

Publication number: CN114286286A
Application number: CN202111559891.0A
Authority: CN
Inventors: 艾艳军; 张一�; 王璇
Original assignee: Zhejiang Geely Holding Group Co Ltd; Zhejiang Shikong Daoyu Technology Co Ltd
Current assignee: Zhejiang Geely Holding Group Co Ltd; Zhejiang Shikong Daoyu Technology Co Ltd
Priority date: 2021-12-20
Filing date: 2021-12-20
Publication date: 2022-04-05

Abstract

The present application provides a time synchronization method, device, medium, and program product, by acquiring first ranging information sent by a satellite navigation system and auxiliary information sent by an auxiliary satellite system, the auxiliary information including: the method comprises the steps that precise orbit data and precise clock error data of a navigation satellite and an auxiliary satellite, second ranging information measured by the auxiliary satellite and a first time difference uploaded to the auxiliary satellite by a data center are obtained; determining a second time difference between the local time and the navigation time of the ground terminal when the ground terminal is positioned and resolved by using a preset positioning model according to the first ranging information and the auxiliary information; and correcting the local time according to the first time difference and the second time difference so as to synchronize the local time with the reference time. The auxiliary satellite system covers the whole world, so that the technical problem that the time transmission must be carried out by depending on a ground communication network in the prior art is solved.

Description

Time synchronization method, apparatus, medium, and program product

Technical Field

The present application relates to the field of satellite technologies, and in particular, to a time synchronization method, device, medium, and program product.

Background

The time information is the root of signal analysis, frequency transmission, synchronization comparison and information transmission, and in the navigation and positioning process, time synchronization is also required to be performed at each terminal to ensure the positioning accuracy.

Currently, in time reference synchronization, a satellite navigation System, such as a GPS (Global Positioning System) System, can be used to perform time synchronization while performing Positioning by using a precise single-point Positioning technology.

However, the precise single-point positioning technology needs to be supported by a terrestrial communication network. The precise orbit information and the precise clock error information of the navigation satellite released by the international global navigation satellite system service organization are transmitted through a ground communication network so as to improve the positioning precision. Namely, the prior art has the technical problem that the time transmission must depend on a ground communication network.

Disclosure of Invention

The application provides a time synchronization method, a device, a medium and a program product, which are used for solving the technical problem that the time transmission must depend on a ground communication network in the prior art.

In a first aspect, the present application provides a time synchronization method applied to a ground terminal, including:

acquiring first ranging information sent by a satellite navigation system and auxiliary information sent by an auxiliary satellite system, wherein the satellite navigation system comprises a plurality of navigation satellites, the auxiliary satellite system comprises a plurality of auxiliary satellites, and the auxiliary information comprises: the precise orbit data and the precise clock error data of the navigation satellite and the auxiliary satellite, the second ranging information measured by the auxiliary satellite, and the first time difference uploaded to the auxiliary satellite by the data center comprise: a time difference between a reference time of the data center and a navigation time of the navigation satellite;

utilizing a preset positioning model, determining a second time difference when positioning and resolving the ground terminal according to the first ranging information and the auxiliary information, wherein the second time difference comprises: a time difference between a local time of the ground terminal and the navigation time;

and correcting the local time according to the first time difference and the second time difference so as to synchronize the local time with the reference time.

In one possible design, the second orbit of the secondary satellite is lower than the first orbit of the navigation satellite.

Optionally, the auxiliary satellite is a low earth orbit satellite.

In one possible design, the precise orbit data includes: first precise orbit data of a navigation satellite and second precise orbit data of an auxiliary satellite, the precise clock error data comprising: a navigation clock error, which is the inherent bias of the satellite clock on the navigation satellite, and a third time difference, which is the time difference of the clock time of the auxiliary satellite relative to the navigation time;

correspondingly, utilize and preset the location model, according to first range finding information and auxiliary information, when positioning to ground terminal and resolving, confirm the second time difference, include:

combining the first ranging information and the second ranging information according to the precise orbit data and the precise clock error data by using a preset deviation calibration model to determine comprehensive ranging information;

positioning and resolving the ground terminal by using a preset positioning model according to the comprehensive ranging information to determine a second time difference;

wherein the second ranging information is used for: and when positioning calculation is carried out, the convergence speed of the positioning calculation is accelerated so as to obtain the second time difference more quickly.

In one possible design, modifying the local time according to the first time difference and the second time difference to synchronize the local time with the reference time includes:

acquiring a local frequency signal generated by a local frequency source in a ground terminal;

and adjusting the local frequency signal according to the first time difference and the second time difference so as to synchronize a second pulse corresponding to the local time with a first pulse corresponding to the reference time.

In a second aspect, the present application provides a time synchronization method applied to an auxiliary satellite, including:

obtaining upper note data sent by a data center and first ranging information sent by a navigation satellite of a satellite navigation system, wherein the upper note data comprises: a first time difference between a reference time of the data center and a navigation time of the navigation satellite, and a first precise orbit data and a navigation clock error of the navigation satellite, wherein the navigation clock error is an inherent deviation of a satellite clock on the navigation satellite;

determining second precise orbit data and a third time difference of the auxiliary satellite according to the first precise orbit data, the navigation clock difference and the first ranging information by using a preset positioning model, wherein the third time difference is a difference value of the clock time of the auxiliary satellite relative to the navigation time;

determining auxiliary information according to the upper note data, the second precise orbit data, the third time difference and second ranging information for assisting satellite measurement;

and sending the auxiliary information to the ground terminal so that the ground terminal performs time synchronization on the local time of the ground terminal and the reference time according to the received first ranging information and the auxiliary information by using a preset positioning model.

In one possible design, determining the aiding information based on the upper-note data, the second precise orbit data, the third time difference, and the second ranging information for aiding the satellite measurement includes:

adjusting a satellite frequency source on the auxiliary satellite according to the second precise orbit data and the third time difference to synchronize the clock time and the navigation time so as to improve the positioning function after the second ranging information is combined with the first ranging information;

and combining and coding the upper annotation data, the second precise orbit data and the second ranging information to determine auxiliary information.

Optionally, the auxiliary satellite is a low earth orbit satellite.

In a third aspect, the present application provides a time synchronization method applied to a data center, including:

acquiring reference time generated by an atomic clock group and first precise orbit data and a navigation clock error of a navigation satellite in a satellite navigation system, wherein the navigation clock error is inherent deviation of a satellite clock on the navigation satellite;

determining a first time difference between the reference time and the navigation time of the navigation satellite according to the first precise orbit data and the navigation clock error;

determining upper note data according to the first precise orbit data, the navigation clock error and the first time error;

and sending the upper-injection data to an auxiliary satellite of an auxiliary satellite system so as to send auxiliary information to the ground terminal by using the auxiliary satellite, so that the ground terminal performs time synchronization on the local time of the ground terminal and the reference time according to the received first ranging information and the auxiliary information measured by the navigation satellite by using a preset positioning model.

Optionally, the auxiliary satellite is a low earth orbit satellite.

In a fourth aspect, the present application provides a time synchronization apparatus, comprising:

an obtaining module, configured to obtain first ranging information sent by a satellite navigation system and auxiliary information sent by an auxiliary satellite system, where the satellite navigation system includes a plurality of navigation satellites, the auxiliary satellite system includes a plurality of auxiliary satellites, and the auxiliary information includes: the precise orbit data and the precise clock error data of the navigation satellite and the auxiliary satellite, the second ranging information measured by the auxiliary satellite, and the first time difference uploaded to the auxiliary satellite by the data center comprise: a time difference between a reference time of the data center and a navigation time of the navigation satellite;

a processing module to:

Optionally, the auxiliary satellite is a low earth orbit satellite.

correspondingly, the processing module is configured to:

In one possible design, the obtaining module is further configured to obtain a local frequency signal generated by a local frequency source in the ground terminal;

and the processing module is used for adjusting the local frequency signal according to the first time difference and the second time difference so as to synchronize a second pulse corresponding to the local time with a first pulse corresponding to the reference time.

In a fifth aspect, the present application provides a time synchronization apparatus, including:

the acquisition module is used for acquiring the upper note data sent by the data center and first ranging information sent by a navigation satellite of a satellite navigation system, wherein the upper note data comprises: a first time difference between a reference time of the data center and a navigation time of the navigation satellite, and a first precise orbit data and a navigation clock error of the navigation satellite, wherein the navigation clock error is an inherent deviation of a satellite clock on the navigation satellite;

a processing module to:

In one possible design, the processing module is to:

Optionally, the auxiliary satellite is a low earth orbit satellite.

In a sixth aspect, the present application provides a time synchronization apparatus, comprising:

the system comprises an acquisition module, a data acquisition module and a data acquisition module, wherein the acquisition module is used for acquiring reference time generated by an atomic clock group and first precise orbit data and a navigation clock error of a navigation satellite in a satellite navigation system, and the navigation clock error is inherent deviation of a satellite clock on the navigation satellite;

a processing module to:

Optionally, the auxiliary satellite is a low earth orbit satellite.

In a seventh aspect, the present application provides a time synchronization system, including: the system comprises a plurality of ground terminals, at least one data center, a satellite navigation subsystem and an auxiliary satellite subsystem, wherein the satellite navigation subsystem comprises a plurality of navigation satellites, and the auxiliary satellite subsystem comprises a plurality of auxiliary satellites;

a ground terminal configured to perform any one of the possible time synchronization methods provided by the first aspect;

an auxiliary satellite configured to perform any one of the possible time synchronization methods provided by the second aspect;

a data center configured to perform any one of the possible time synchronization methods provided by the third aspect.

In an eighth aspect, the present application provides a ground terminal comprising:

a memory for storing program instructions;

and the processor is used for calling and executing the program instructions in the memory and executing any one of the possible time synchronization methods provided by the first aspect.

In a ninth aspect, the present application provides an assisted satellite comprising:

a memory for storing program instructions;

and the processor is used for calling and executing the program instructions in the memory and executing any one of the possible time synchronization methods provided by the second aspect.

In a tenth aspect, the present application provides an electronic device comprising:

a memory for storing program instructions;

and the processor is used for calling and executing the program instructions in the memory and executing any one of the possible time synchronization methods provided by the third aspect.

In an eleventh aspect, the present application provides a storage medium having a computer program stored thereon, the computer program being configured to execute any one of the possible time synchronization methods provided in the first aspect.

In a twelfth aspect, the present application provides a storage medium, wherein a computer program is stored in the storage medium, and the computer program is used to execute any one of the possible time synchronization methods provided in the second aspect.

In a thirteenth aspect, the present application provides a storage medium, wherein a computer program is stored in the storage medium, and the computer program is used to execute any one of the possible time synchronization methods provided in the third aspect.

In a fourteenth aspect, the present application further provides a computer program product comprising a computer program, which when executed by a processor, implements any one of the possible time synchronization system methods provided in the first aspect.

In a fifteenth aspect, the present application further provides a computer program product comprising a computer program which, when executed by a processor, implements any one of the possible time synchronization system methods provided by the second aspect.

In a sixteenth aspect, the present application further provides a computer program product comprising a computer program which, when executed by a processor, implements any one of the possible time synchronization system methods provided in the third aspect.

The application provides a time synchronization method, a device, equipment, a medium and a program product, uploading upper note data to an auxiliary satellite through a data center, wherein the upper note data comprise: a first time difference, first precise orbit data of a navigation satellite and a navigation clock difference, the first time difference comprising: the time difference between the reference time of the data center and the navigation time of the navigation satellite, wherein the navigation clock difference is the inherent deviation of a satellite clock on the navigation satellite; the auxiliary satellite subsystem receives the upper annotation data and first ranging information sent by a navigation satellite through an auxiliary satellite; synchronizing the clock time and the navigation time of the auxiliary satellite according to the upper annotation data and the first ranging information; determining auxiliary information according to second ranging information measured by the auxiliary satellite and the upper injection data, and sending the auxiliary information to each ground terminal; the ground terminal receives the auxiliary information and the first ranging information; determining a second time difference when the ground terminal is positioned and solved according to the first ranging information and the auxiliary information by using a preset positioning model; and correcting the local time according to the first time difference and the second time difference so as to synchronize the local time of the ground terminal with the reference time. The technical problem that time transmission must be carried out by depending on a ground communication network in the prior art is solved. By using the global low-orbit navigation enhanced satellite, the time distribution function without ground network support and communication area limitation is realized, and the technical effect of high-precision time synchronization of a single receiver can be realized.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.

Fig. 1 is a schematic diagram of a time synchronization system and an application scenario thereof according to an embodiment of the present application;

fig. 2 is a schematic flowchart of a time synchronization method according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of a data center according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of a data processing device in an auxiliary satellite according to an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of a data center according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a time synchronization apparatus according to an embodiment of the present application;

fig. 7 is a schematic structural diagram of another time synchronization apparatus according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of another time synchronization apparatus according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of an electronic device provided in the present application.

With the above figures, there are shown specific embodiments of the present application, which will be described in more detail below. These drawings and written description are not intended to limit the scope of the inventive concepts in any manner, but rather to illustrate the inventive concepts to those skilled in the art by reference to specific embodiments.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, including but not limited to combinations of embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any inventive step are within the scope of the present application.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the drawings described above, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The following description is made for some of the basic concepts and words involved in the present application:

the global navigation positioning technology is a technology for positioning and timing a user terminal by utilizing known positions of more than 4 navigation satellites and carrying out backward intersection calculation, the navigation satellites maintain time reference by relying on a high-precision atomic clock carried by the navigation satellites, and the time for transmitting signals from the navigation satellites to the user terminal is calculated by utilizing navigation ranging signals, so that the time transmission function can be completed by the precision time and the transmission time of the navigation satellites.

The positioning accuracy achieved by the user side through the navigation satellite is not high, generally, the positioning accuracy can reach the positioning accuracy of 3 meters horizontally and 5m vertically, and correspondingly, the time transfer accuracy of 50 nanoseconds can be achieved by the user side.

If the time synchronization precision needs to be further improved, a time difference transmission method needs to be comprehensively utilized to perform time transmission in a comparison mode. Time difference measurements using GNSS (Global Navigation Satellite System) technology are typically done using averages measured over a period of time or using precise point-and-point positioning.

GNSS positioning is an observation that uses pseudoranges, ephemeris, satellite launch times, etc. from a set of satellites, while the user clock error must also be known. The global navigation satellite system is a space-based radio navigation positioning system that can provide users with all-weather 3-dimensional coordinates and velocity and time information at any location on the earth's surface or in near-earth space. Therefore, it is popular to say that if you want to know the altitude in addition to the longitude and latitude, you must receive 4 satellites to locate accurately.

The precise single-point positioning technology is to eliminate the above mentioned satellite positioning orbit error and satellite clock error by using the satellite precise orbit and clock error information generated by the International global navigation satellite system Service organization, such as IGS (International GNSS Service) or other organizations.

With the continuous maturity of the application of the precise single-point positioning, the real-time precise single-point positioning based on the network data distribution can increase the positioning precision to centimeter level in real time and increase the time transfer precision to nanosecond level, however, the ionosphere information and the troposphere information which are difficult to correct cause the precision convergence to be slow, and a user usually needs to observe for 30-60 minutes to be able to reach the centimeter level positioning precision and the nanosecond level time transfer precision. In addition, in the absence of a ground network, the precise track information and the precise clock error information cannot be transmitted, so that the method cannot be realized.

In summary, the prior art solutions have the following drawbacks and disadvantages:

1) the time synchronization convergence speed is slow: in the above prior art, the time is transmitted by using global navigation satellite single-point positioning, and the real-time positioning precision is only several meters, so that the precision can only reach tens of nanoseconds, and the time synchronization precision requirement of high-precision frequency synchronization is difficult to meet. By using the precise single-point positioning technology, the convergence time usually needs 30-60 minutes, and the convergence speed is slow, so that the requirement of fast time transfer is difficult to meet.

2) Region and communication restriction: according to the technical scheme, when data products such as precision track information and precision clock error information are acquired, a ground network is required to be used for transmission, and time transmission based on precision single-point positioning cannot be realized under the condition that the ground network is not available.

3) Relying on an atomic clock: in the above prior art schemes, external atomic clock signals are transmitted to the inside of the receiver, and the receiver compares the time difference between the atomic clock signals and the local oscillation signals, rather than outputting high-precision time synchronization information.

4) It is difficult to achieve multi-terminal synchronization: the above prior art scheme generally performs data transmission on two receivers, compares the two receivers with each other to realize time synchronization, and if the time of three or more terminals needs to be synchronized, a complex organization structure is required, which causes great difficulty in engineering practice.

In summary, the prior art has a technical problem that the time transmission must depend on a terrestrial communication network.

In order to solve the above problems, the inventive concept of the present application is:

besides the navigation satellite system, a set of auxiliary satellite system capable of covering the whole world is constructed. For example, a low-orbit navigation enhancement system is constructed by using the characteristics of low cost and easy emission of a low-orbit satellite, and the low-orbit navigation enhancement satellite is used for transmitting the precise orbit information and the precise clock error information of the navigation satellite, so that global seamless information broadcast coverage can be realized, and the dependence of the prior art on a ground communication network is broken through. In addition, the low-orbit navigation enhancement signal, namely the auxiliary signal sent by the auxiliary satellite, can accelerate the convergence speed of the precise single-point positioning to a certain extent, and can help a user to quickly acquire a high-precision time transfer result.

In addition, the data service center, namely the data center, which is built by the data service center is used for transmitting the precise orbit information, the precise clock error information and the correction information of the standard time to an auxiliary satellite, such as a low-earth-orbit navigation enhanced satellite, and when a signal is modulated by a low-earth-orbit navigation enhanced satellite signal, the data is broadcast by using a wave band close to that of a GNSS navigation satellite. After receiving the signal, the time synchronization terminal, i.e. the ground terminal, adjusts its own time information to the standard time information, so as to realize the automatic time synchronization among a plurality of ground terminals and achieve the function of time transmission or time synchronization.

In summary, the present application can solve the following problems:

1) the low-orbit navigation enhanced satellite is utilized to realize the broadcasting of precise products, breaks through the dependence of the traditional method on a ground network, expands the usable area range and can be used in unmanned areas.

2) By utilizing the broadcasting of the signals, the independent work of the synchronous terminal is realized, and the signal interaction is not needed.

3) The output of external high-precision pulse signals and time information is realized.

4) And the centralized multi-terminal synchronization technology is realized by using the centralized frequency reference and signal broadcasting.

5) And the low-orbit satellite signals are utilized to realize the quick convergence and the quick time synchronization of the precise point positioning.

The following describes the technical solutions of the present application and how to solve the above technical problems with specific embodiments. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of a time synchronization system and an application scenario thereof according to an embodiment of the present application. As shown in fig. 1, the time synchronization system includes: a plurality of ground terminals 101, at least one data center 102, a satellite navigation subsystem comprising a plurality of navigation satellites 103, and an auxiliary satellite subsystem comprising a plurality of auxiliary satellites 104. The orbit of the auxiliary satellite 104 is lower than that of the navigation satellite 103, so that the rotation speed of the auxiliary satellite 104 around the earth is faster, the second change speed of the second ranging information observed by the auxiliary satellite 104 to the ground is faster than the first change speed of the first ranging information observed by the navigation satellite 103 to the ground, and after the two are combined with each other, the navigation precision of the navigation satellite 103 can be improved, and meanwhile, the time error corresponding to navigation positioning can be further shortened to within tens of nanoseconds from the existing tens of nanoseconds, even within the order of several nanoseconds. The precise orbit information and the precise clock error information of the navigation satellite which needs to be used in the positioning process are transmitted by injecting data to the auxiliary satellite 104 through the self-built data center 102, so that the ground terminal 101 does not need to rely on a ground communication network to receive the information, the dependence on the ground communication network is eliminated, and the satellite network of the auxiliary satellite subsystem covers the whole earth, so that the region limitation is eliminated, and the navigation positioning and the time information transmission can be realized in remote regions without the ground communication network or regions with weak ground communication network signals.

The following describes in detail how to implement the time synchronization method provided in the present application.

Fig. 2 is a schematic flowchart of a time synchronization method according to an embodiment of the present application. As shown in fig. 2, the specific steps of the time synchronization method include:

s201, acquiring reference time generated by an atomic clock group and first precise orbit data and a navigation clock error of a navigation satellite in a satellite navigation system.

In this step, the navigation clock error is an inherent deviation of a satellite clock on the navigation satellite, that is, precise clock error information of the navigation satellite, and is used to represent an error value between the time of the satellite clock on the navigation satellite and the world standard time issued by the authoritative time issuing authority, where the error value is generated by a certain physically unavoidable delay when the satellite clock is started, and can be measured by a two-way comparison method.

Fig. 3 is a schematic structural diagram of a data center according to an embodiment of the present application. As shown in fig. 3, the data center 300 includes: an atomic clock group 301, a network device 302, a GNSS receiver 303, an upcasting device 304, and a two-way comparison device 305.

Specifically, the data center 300 is equipped with an atomic clock group 301 as a time reference, and the time reference of the atomic clock group 301 is synchronized with the reference time issued by the authority through a bidirectional comparison device 305 by using fiber bidirectional comparison or satellite bidirectional comparison.

The network device 302 acquires the precise orbit information and the precise clock error information of the GNSS navigation satellite from an authoritative time distribution mechanism, such as an IGS or other organization, through the internet or other data transmission network, and transmits the precise orbit information and the precise clock error information to the GNSS receiver 303.

And S202, determining a first time difference between the reference time and the navigation time of the navigation satellite according to the first precise orbit data and the navigation clock error.

In this step, specifically, the time of the atomic clock group 301 is input to the GNSS receiver 303, and the GNSS receiver 303 completes the precise single-point positioning by using the precise orbit information and the precise clock offset information, and operates for a long time. After the precise single-point positioning is completed, the difference between the satellite time (also called navigation time) of the navigation satellite and the reference time (i.e. the first time difference) is measured.

In one possible design, the first time difference may be calculated by using multiple receivers, i.e., multiple GNSS receivers 303, so that after redundant processing, the measurement accuracy of the satellite time of the navigation satellite, i.e., the navigation time, and the time difference (i.e., the first time difference) between the atomic clock group 301 may be improved.

And S203, determining the upper note data according to the first precise orbit data, the navigation clock error and the first time difference.

In this step, the annotating device 304 receives the GNSS satellite ephemeris and precision clock error information, i.e., the precision orbit information and the navigation clock error, forwarded by the network device 302, and receives the first time difference transmitted by the GNSS receiver 303, and performs packet encoding on these data, i.e., determines the annotating data.

And S204, transmitting the upper note data to an auxiliary satellite of the auxiliary satellite system.

In this step, the second orbit of the auxiliary satellite is lower than the first orbit of the navigation satellite.

The data center 300 injects the measured difference between the GNSS navigation satellite and the reference time, i.e., the first time difference, and the precise orbit and clock error information to the auxiliary satellite of the auxiliary satellite system.

Optionally, the auxiliary satellite is a low-orbit satellite, such as a low-orbit navigation enhancement satellite.

Specifically, the betting device 304 transmits the betting data to the auxiliary satellite via the antenna.

The following begins with an introduction of the steps performed by the secondary satellite:

s205, the upper note data sent by the data center and first ranging information sent by a navigation satellite of the satellite navigation system are obtained.

Fig. 4 is a schematic structural diagram of a data processing device in an auxiliary satellite according to an embodiment of the present disclosure. As shown in fig. 4, the auxiliary satellite 400 includes: a satellite receiving antenna 401, a signal encoder 402, an on-board GNSS receiver 403, a satellite frequency source 404, a signal generator 405, and a satellite transmitting antenna 406.

In this step, specifically, the auxiliary satellite 400, such as a low earth orbit satellite, receives the uplink data from the terrestrial data center through the satellite receiving antenna 401, and transmits the data to the signal encoder 402, and the signal encoder 402 re-encodes the data into a protocol format for signal broadcasting.

Meanwhile, the on-board GNSS receiver 403 receives the first ranging information, which is the signal transmitted by the GNSS navigation satellite, and the upper-note data, which is the information generated by the signal encoder 402.

S206, determining second precise orbit data and a third time difference of the auxiliary satellite according to the first precise orbit data, the navigation clock difference and the first distance measurement information by using a preset positioning model.

In this step, the third time difference is the difference of the clock time of the auxiliary satellite with respect to the navigation time.

Specifically, the on-board GNSS receiver 403 performs fine positioning and fine timing by using a preset positioning model (e.g., a fine single-point positioning algorithm model). The fine positioning generates satellite orbit information, i.e., second fine orbit data, of an auxiliary satellite, such as a low-earth-orbit navigation enhancement satellite. The timing results of the fine timing generation include: the difference between the clock time of the auxiliary satellite relative to the navigation time, i.e., the third time difference, may regulate the satellite frequency source 404 such that the satellite time of the auxiliary satellite 400 is synchronized with the satellite time of the navigation satellite, i.e., the navigation time.

And S207, determining auxiliary information according to the upper note data, the second precise orbit data, the third time difference and second ranging information for assisting satellite measurement.

In this embodiment, the present step includes:

Specifically, the on-board GNSS receiver 403 feeds back the third time difference to the satellite frequency source 404 and the signal encoder 402. The signal encoder 402 transmits the uplink data and the third time difference to the signal generator 405, the signal generator 405 measures the ground under the support of the adjusted satellite frequency source 404 to obtain second ranging information, and then determines auxiliary information, also called a navigation enhancement signal, according to the uplink data and the second ranging information, which includes: the precise orbit information (namely, the first precise orbit data) of the GNSS navigation satellite, the precise clock error information, the DCB (Differential Code Bias, GNSS Differential Code Bias) data product, the navigation enhancement information such as the low orbit satellite navigation ephemeris (namely, the second precise orbit data) and the like, and the second ranging information, such as the ranging Code, namely, the new ranging signal observed quantity can greatly accelerate the convergence speed of the ground terminal during positioning, thereby realizing the function of rapid positioning.

It should be noted that the second ranging information includes: the measured distance between the low-orbit navigation enhanced satellite and the ground receiving terminal can participate in overall positioning time service resolving, belongs to the introduction of new signals, the navigation enhanced information improves the positioning performance of GNSS positioning, and simultaneously contains the time difference between a low-orbit navigation enhanced system and standard time, and is used as correction data to be broadcasted to a user terminal set ground terminal, the user terminal analyzes the time correction information contained in a low-orbit navigation satellite clock, so that the time correction information can be formed, and the local time of the ground terminal is corrected to the standard time.

And S208, sending the auxiliary information to the ground terminal.

Specifically, the auxiliary satellite 400 transmits the auxiliary information to the ground terminal via the satellite transmitting antenna 406.

S209, acquiring the first ranging information sent by the satellite navigation system and the auxiliary information sent by the auxiliary satellite system.

In this step, the auxiliary information includes: the precise orbit data and the precise clock error data of the navigation satellite and the auxiliary satellite, the second ranging information measured by the auxiliary satellite, and the first time difference uploaded to the auxiliary satellite by the data center comprise: a time difference between a reference time of the data center and a navigation time of the navigation satellite.

Fig. 5 is a schematic structural diagram of a data center according to an embodiment of the present application. As shown in fig. 5, the data center 500 includes: the system comprises an antenna 501, a low-orbit navigation receiving module 502, a GNSS module 503, a frequency source module 504 and a time-frequency regulation module 505.

Specifically, the antenna 501 receives an auxiliary signal (including a low-orbit navigation enhancement signal) and a GNSS signal, that is, first ranging information, and divides the signal into two paths by the power dividing device, and transmits the two paths of signals to the low-orbit navigation receiving module 502 and the GNSS module 503 respectively.

The GNSS module 503 receives the radio frequency information of the antenna 501 to receive the GNSS original observed quantity, i.e., the first ranging information. The low-earth navigation receiving module 502 processes the auxiliary signals of the low-earth navigation augmentation satellites, i.e., the auxiliary satellites, and performs data calculation. The frequency source module 504 provides the low-orbit navigation receiving module 502 and the GNSS module 503 with the local reference time and the local frequency information.

S210, determining a second time difference when the ground terminal is positioned and solved according to the first ranging information and the auxiliary information by using a preset positioning model.

In this step, the second time difference includes: a time difference between a local time of the ground terminal and the navigation time.

In the embodiment, a preset deviation calibration model is used to combine the first ranging information and the second ranging information according to the precise orbit data and the precise clock error data to determine the comprehensive ranging information;

Specifically, the low-orbit navigation receiving module 502 tracks, decodes, and measures the auxiliary signal to obtain a low-orbit navigation observed quantity (i.e., second ranging information), first precise orbit data, a navigation clock error, and a first time difference, and transmits the information to the GNSS module 503. After receiving the resolving information transmitted by the low-orbit navigation receiving module 502, the GNSS module 503 combines the low-orbit navigation ranging signal (i.e., the second ranging information) with the GNSS original observed quantity information (i.e., the first ranging information) to perform precise single-point positioning resolving, and utilizes the fast change characteristic of the low-orbit navigation enhanced ranging information (i.e., the second ranging information) to accelerate the convergence rate of precise single-point positioning and calculate the time information of the local frequency source.

The GNSS module 503 calculates a difference between the local time and the navigation time of the GNSS navigation satellite, that is, a second time difference, and calculates a difference between the local time and the data center time, that is, a fourth time difference, using the first time difference calculated by the data center.

The GNSS module 503 may transmit the fourth time difference to the time-frequency adjustment module 505.

And S211, correcting the local time according to the first time difference and the second time difference so as to synchronize the local time with the reference time.

In this step, the method comprises the following steps: acquiring a local frequency signal generated by a local frequency source in a ground terminal;

Specifically, the time-frequency regulation module 505 receives the reference information of the frequency source module 504, that is, the local time information and the local reference frequency information, and regulates the local reference frequency information generated by the frequency source module 504 according to the fourth time difference, so as to regulate the pulse of the local time to be synchronized with the pulse of the reference time of the data center 300.

The time-frequency regulation module 505 outputs the adjusted pulse information and outputs time information corresponding to the pulse information time.

Through the above process, the ground terminal 500 and the data center 300 are synchronized with each other at the reference time.

It should be noted that, after a plurality of ground terminals simultaneously use the method, time synchronization of each ground terminal can be realized. Because of the auxiliary satellite system, such as the low-orbit navigation enhancement system, the global coverage can be realized and is not limited by the coverage area of the ground communication network.

The adjusted time information of each ground terminal is aligned with the reference time of the data center, so that each ground terminal independently completes time alignment of the data center, and further time synchronization of each terminal is realized.

When the number of the low-orbit navigation satellites is large, the fast-changing geometric configuration of the low-orbit navigation enhanced satellite is utilized, so that the convergence speed of the precise single-point positioning can be improved, the time convergence speed is accelerated, and the fast and precise time transfer is realized.

In summary, the beneficial effects of the embodiments of the present application include:

1) the GNSS precision track information, the clock error information and the difference value between the GNSS time and the standard time are simultaneously broadcast by the self-built data center, and the user side can finish high-precision time tracing only by receiving the GNSS precision track information, the clock error information and the difference value between the GNSS time and the standard time, so that the time synchronization efficiency of the terminal is improved, and the dependence on communication is eliminated.

2) The invention realizes a centralized synchronization scheme based on the time reference of the data center, and can more efficiently realize the time synchronization of multiple terminals with the continuous increase of synchronous terminals.

3) The low-orbit navigation is utilized to enhance the satellite, so that the coverage area of data broadcasting can be greatly increased, and the convergence rate of the terminal is improved.

4) And the external output of the precise time reference can be realized.

The embodiment provides a time synchronization method, which uploads remark data to an auxiliary satellite through a data center, wherein the remark data includes: a first time difference, first precise orbit data of a navigation satellite and a navigation clock difference, the first time difference comprising: the time difference between the reference time of the data center and the navigation time of the navigation satellite, wherein the navigation clock difference is the inherent deviation of a satellite clock on the navigation satellite; the auxiliary satellite subsystem receives the upper annotation data and first ranging information sent by a navigation satellite through an auxiliary satellite; synchronizing the clock time and the navigation time of the auxiliary satellite according to the upper annotation data and the first ranging information; determining auxiliary information according to second ranging information measured by the auxiliary satellite and the upper injection data, and sending the auxiliary information to each ground terminal; the ground terminal receives the auxiliary information and the first ranging information; determining a second time difference when the ground terminal is positioned and solved according to the first ranging information and the auxiliary information by using a preset positioning model; and correcting the local time according to the first time difference and the second time difference so as to synchronize the local time of the ground terminal with the reference time. The technical problem that time transmission must be carried out by depending on a ground communication network in the prior art is solved. By using the global low-orbit navigation enhanced satellite, the time distribution function without ground network support and communication area limitation is realized, and the technical effect of high-precision time synchronization of a single receiver can be realized.

Fig. 6 is a schematic structural diagram of a time synchronization apparatus according to an embodiment of the present application. The time synchronizer 600 may be implemented by software, hardware, or a combination of both.

As shown in fig. 6, the time synchronizer 600 includes:

an obtaining module 601, configured to obtain first ranging information sent by a satellite navigation system and auxiliary information sent by an auxiliary satellite system, where the satellite navigation system includes a plurality of navigation satellites, the auxiliary satellite system includes a plurality of auxiliary satellites, and the auxiliary information includes: the precise orbit data and the precise clock error data of the navigation satellite and the auxiliary satellite, the second ranging information measured by the auxiliary satellite, and the first time difference uploaded to the auxiliary satellite by the data center comprise: a time difference between a reference time of the data center and a navigation time of the navigation satellite;

a processing module 602 configured to:

Optionally, the auxiliary satellite is a low earth orbit satellite.

correspondingly, the processing module 602 is configured to:

In a possible design, the obtaining module 601 is further configured to obtain a local frequency signal generated by a local frequency source in the ground terminal;

the processing module 602 is configured to adjust the local frequency signal according to the first time difference and the second time difference, so that the second pulse corresponding to the local time is synchronized with the first pulse corresponding to the reference time.

It should be noted that the apparatus provided in the embodiment shown in fig. 6 can execute the method steps provided in any of the above method embodiments at the ground terminal side, and the specific implementation principle, technical features, technical term explanation and technical effects thereof are similar, and are not described herein again.

Fig. 7 is a schematic structural diagram of another time synchronization apparatus according to an embodiment of the present application. The time synchronization apparatus 700 may be implemented by software, hardware, or a combination of both.

As shown in fig. 7, the time synchronization apparatus 700 includes:

an obtaining module 701, configured to obtain upper note data sent by a data center and first ranging information sent by a navigation satellite of a satellite navigation system, where the upper note data includes: a first time difference between a reference time of the data center and a navigation time of the navigation satellite, and a first precise orbit data and a navigation clock error of the navigation satellite, wherein the navigation clock error is an inherent deviation of a satellite clock on the navigation satellite;

a processing module 702 configured to:

In one possible design, the processing module 702 is configured to:

Optionally, the auxiliary satellite is a low earth orbit satellite.

It should be noted that the apparatus provided in the embodiment shown in fig. 7 can execute the method steps of the auxiliary satellite side provided in any of the above method embodiments, and the specific implementation principle, technical features, technical term explanation and technical effects thereof are similar and will not be described herein again.

Fig. 8 is a schematic structural diagram of another time synchronization apparatus according to an embodiment of the present application. The time synchronizer 800 may be implemented by software, hardware, or a combination of both.

As shown in fig. 8, the time synchronizer 800 includes:

an obtaining module 801, configured to obtain a reference time generated by an atomic clock group, and first precise orbit data and a navigation clock offset of a navigation satellite in a satellite navigation system, where the navigation clock offset is an inherent deviation of a satellite clock on the navigation satellite;

a processing module 802 configured to:

Optionally, the auxiliary satellite is a low earth orbit satellite.

It should be noted that the apparatus provided in the embodiment shown in fig. 8 can execute the method steps on the data center side provided in any of the above method embodiments, and the specific implementation principle, technical features, technical term explanation and technical effects thereof are similar and will not be described herein again.

Fig. 9 is a schematic structural diagram of an electronic device according to an embodiment of the present application. As shown in fig. 9, the electronic device 900 may include: at least one processor 901 and memory 902. Fig. 9 shows an electronic device as an example of a processor.

And a memory 902 for storing programs. In particular, the program may include program code including computer operating instructions.

Memory 902 may comprise high-speed RAM memory and may also include non-volatile memory (non-volatile memory), such as at least one disk memory.

The processor 901 is configured to execute the computer executable instructions stored in the memory 902 to implement the method steps corresponding to any one of the data center, the auxiliary satellite and the ground terminal in the above method embodiments.

The processor 901 may be a Central Processing Unit (CPU), an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

Alternatively, the memory 902 may be separate or integrated with the processor 901. When the memory 902 is a device independent of the processor 901, the electronic device 900 may further include:

a bus 903 for connecting the processor 901 and the memory 902. The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended ISA (EISA) bus, or the like. Buses may be classified as address buses, data buses, control buses, etc., but do not represent only one bus or type of bus.

Alternatively, in a specific implementation, if the memory 902 and the processor 901 are integrated into a chip, the memory 902 and the processor 901 may complete communication through an internal interface.

An embodiment of the present application further provides a computer-readable storage medium, where the computer-readable storage medium may include: various media that can store program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and in particular, the computer-readable storage medium stores program instructions for the methods in the above method embodiments.

An embodiment of the present application further provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the computer program implements the method in the foregoing method embodiments.

Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

It will be understood that the present application is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A time synchronization method is applied to a ground terminal, and comprises the following steps:

acquiring first ranging information sent by a satellite navigation system and auxiliary information sent by an auxiliary satellite system, wherein the satellite navigation system comprises a plurality of navigation satellites, the auxiliary satellite system comprises a plurality of auxiliary satellites, and the auxiliary information comprises: the precise orbit data and the precise clock error data of the navigation satellite and the auxiliary satellite, the second ranging information measured by the auxiliary satellite, and the first time difference uploaded to the auxiliary satellite by the data center are as follows: a time difference between a reference time of the data center and a navigation time of the navigation satellite;

and determining a second time difference by using a preset positioning model according to the first ranging information and the auxiliary information when the ground terminal is positioned and solved, wherein the second time difference comprises: a time difference between a local time of the ground terminal and the navigation time;

2. The method of claim 1, wherein the second orbit of operation of the auxiliary satellite is lower than the first orbit of operation of the navigation satellite.

3. The method of time synchronization of claim 2, wherein the auxiliary satellite is a low earth orbit satellite.

4. The time synchronization method according to claim 1, wherein the fine orbit data comprises: first precise orbit data of the navigation satellite and second precise orbit data of the auxiliary satellite, the precise clock error data comprising: a navigation clock bias that is an inherent bias of a satellite clock on the navigation satellite and a third time difference that is a time difference of a clock time of the secondary satellite relative to the navigation time;

correspondingly, when the ground terminal is located and resolved by using a preset location model according to the first ranging information and the auxiliary information, determining a second time difference comprises:

performing the positioning calculation on the ground terminal by using the preset positioning model according to the comprehensive ranging information to determine the second time difference;

wherein the second ranging information is used for: and when the positioning calculation is carried out, the convergence rate of the positioning calculation is accelerated so as to obtain the second time difference more quickly.

5. The method for time synchronization according to any one of claims 1 to 4, wherein the modifying the local time according to the first time difference and the second time difference to synchronize the local time with the reference time comprises:

acquiring a local frequency signal generated by a local frequency source in the ground terminal;

6. A method for time synchronization, applied to an auxiliary satellite, comprising:

determining auxiliary information according to the upper note data, the second precise orbit data, the third time difference and second ranging information measured by the auxiliary satellite;

and sending the auxiliary information to a ground terminal so that the ground terminal performs time synchronization on the local time of the ground terminal and the reference time according to the received first ranging information and the auxiliary information by using a preset positioning model.

7. The method according to claim 6, wherein the determining the aiding information according to the uplink data, the second precise orbit data, the third time difference and the second ranging information measured by the aiding satellite comprises:

and combining and coding the upper-note data, the second precise orbit data and the second ranging information to determine the auxiliary information.

8. The method according to claim 6 or 7, wherein the second orbit of the auxiliary satellite is lower than the first orbit of the navigation satellite.

9. The method of time synchronization of claim 8, wherein the auxiliary satellite is a low earth orbit satellite.

10. A time synchronization method is applied to a data center and comprises the following steps:

and sending the upper note data to an auxiliary satellite of an auxiliary satellite system so as to send auxiliary information to a ground terminal by using the auxiliary satellite, so that the ground terminal performs time synchronization on the local time of the ground terminal and the reference time according to the received first ranging information measured by the navigation satellite and the auxiliary information by using a preset positioning model.

11. The method of claim 10, wherein the second orbit of operation of the auxiliary satellite is lower than the first orbit of operation of the navigation satellite.

12. The method of time synchronization of claim 11, wherein the auxiliary satellite is a low earth orbit satellite.

13. A time synchronization system, comprising: a plurality of ground terminals, at least one data center, a satellite navigation subsystem comprising a plurality of navigation satellites, and an auxiliary satellite subsystem comprising a plurality of auxiliary satellites;

the ground terminal configured to perform the time synchronization method of any one of claims 1 to 5;

the auxiliary satellite configured to perform the time synchronization method of any one of claims 6 to 9;

the data center configured to perform the time synchronization method of any one of claims 10 to 12.

14. A ground terminal, comprising: a processor and a memory;

the memory for storing a computer program for the processor;

the processor is configured to perform the time synchronization method of any one of claims 1 to 5 via execution of the computer program.

15. An auxiliary satellite, comprising: a processor and a memory;

the memory for storing a computer program for the processor;

the processor is configured to perform the time synchronization method of any one of claims 6 to 9 via execution of the computer program.

16. An electronic device, comprising: a processor and a memory;

the memory for storing a computer program for the processor;

the processor is configured to perform the time synchronization method of any one of claims 10 to 12 via execution of the computer program.

17. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method for time synchronization according to any one of claims 1 to 5.

18. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method for time synchronization according to any one of claims 6 to 9.

19. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method for time synchronization according to any one of claims 10 to 12.

20. A computer program product having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the time synchronization method of any of claims 1 to 5.

21. A computer program product having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the time synchronization method of any one of claims 6 to 9.

22. A computer program product having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the time synchronization method of any of claims 10 to 12.