Satellite system time synchronization method and device

Abstract

The invention discloses a satellite system time synchronization method and device, which can be used in the technical field of constellation management. The satellite system time synchronization method comprises the steps that joint clock correction estimation is carried out according to clock correction resolving results of all satellite-earth observation pairs of a satellite system and clock correction resolving results of all inter-satellite observation pairs, a joint clock correction estimation result is obtained, each satellite-earth observation pair is an observation combination composed of a ground station and a first satellite, and each inter-satellite observation pair is an observation combination composed of a second satellite and a third satellite; each inter-satellite observation pair is an observation combination formed by a second satellite and one first satellite or another second satellite; and sending the joint clock error estimation result to enable the satellite system to perform time synchronization. According to the satellite system time synchronization method and device provided by the invention, by integrating the time synchronization data of the satellite-earth observation pair and the inter-satellite observation pair and carrying out combined clock error estimation, the problem of accumulative errors possibly caused by local synchronization is solved, and the effect of ensuring the time reference consistency of the satellite system is achieved.

Description

Technical Field

[0001] The present application relates to the field of constellation management technology, and in particular to a satellite system time synchronization method and device. Background Art

[0002] Currently, low-orbit satellite systems, as an important supplement to terrestrial mobile communication systems, have become a core component of the integrated information network of space, land, and sea. Low-orbit satellites operate in relatively low orbits, offer short transmission latency, and offer flexible networking, effectively addressing the issue of insufficient terrestrial communication network coverage. However, the normal operation of low-orbit satellite systems relies on network-wide time synchronization. This is particularly true in complex communication environments, where GPS or Beidou signals may be unavailable, rendering the system unable to synchronize time. Network-wide time synchronization plays a crucial role in ensuring communication coordination, information transmission accuracy, and system reliability within the low-orbit satellite system, directly impacting the service capabilities and operational efficiency of the integrated information network of space, land, and sea. Therefore, ensuring time synchronization within the low-orbit satellite system without an external timing signal has become a critical issue that needs to be addressed. Summary of the Invention

[0003] To solve at least some of the above technical problems, embodiments of the present application provide a satellite system time synchronization method and apparatus.

[0004] On the one hand, an embodiment of the present application provides a satellite system time synchronization method, including: performing a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system to obtain a joint clock error estimation result, wherein each of the satellite-to-ground observation pairs is an observation combination consisting of a ground station and a first satellite, and each of the inter-satellite observation pairs is an observation combination consisting of a second satellite and one of the first satellites or another second satellite; sending the joint clock error estimation result to enable the satellite system to be time synchronized.

[0005] In some embodiments, a direct communication link is configured between the first satellite and at least one ground station of the satellite system, and no direct communication link is configured between the second satellite and the ground station of the satellite system.

[0006] In some embodiments, a direct communication link is configured between the first satellite and the ground station constituting a satellite-to-ground observation pair; a direct communication link is configured between the second satellite and the first satellite constituting an inter-satellite observation pair; and a direct communication link is configured between the two second satellites constituting an inter-satellite observation pair.

[0007] In some embodiments, performing a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair of the satellite system and the clock error solution results of each inter-satellite observation pair to obtain a joint clock error estimation result includes: selecting a clock of one of the ground station, the first satellite, and the second satellite of the satellite system as a reference clock; performing a joint clock error estimation relative to the reference clock based on the clock error solution results of each satellite-to-ground observation pair of the satellite system and the clock error solution results of each inter-satellite observation pair to obtain a joint clock error estimation result.

[0008] In some embodiments, performing a joint clock error estimation relative to the reference clock based on the clock error solution results of each satellite-to-ground observation pair of the satellite system and the clock error solution results of each inter-satellite observation pair to obtain a joint clock error estimation result includes: performing a joint clock error estimation relative to the reference clock based on the clock error observation values, clock error standard deviations of each satellite-to-ground observation pair of the satellite system and the clock error observation values, clock error standard deviations of each inter-satellite observation pair to obtain a joint clock error estimation result.

[0009] In some embodiments, the method of performing a joint clock error estimation relative to the reference clock based on the clock error observation values, clock error standard deviations of each satellite-to-ground observation pair of the satellite system and the clock error observation values, clock error standard deviations of each inter-satellite observation pair to obtain a joint clock error estimation result includes: constructing a clock error observation vector based on the clock error observation values ​​of each satellite-to-ground observation pair of the satellite system and the clock error observation values ​​of each inter-satellite observation pair; constructing a weight matrix based on the clock error standard deviations of each satellite-to-ground observation pair and the clock error standard deviations of each inter-satellite observation pair; constructing a design matrix based on the link establishment relationship between the first satellite and the ground station in each satellite-to-ground observation pair and the link establishment relationship between the second satellite and the first satellite or another second satellite in each inter-satellite observation pair; performing a joint clock error estimation relative to the reference clock based on the clock error observation vector, the weight matrix and the design matrix to obtain a joint clock error estimation result, wherein the joint clock error estimation result includes the clock error estimation value of at least one of the following relative to the reference clock: the first satellite, the second satellite, and the ground station.

[0010] In some embodiments, sending the joint clock error estimation result to synchronize the satellite system time includes: sending the clock error estimation value to the corresponding satellite, so that the satellite adjusts the clock based on the received clock error estimation value, thereby achieving inter-satellite and / or satellite-to-ground time synchronization of the satellite system.

[0011] In some embodiments, sending the joint clock error estimation result to synchronize the satellite system time includes: sending the clock error estimation value to the corresponding ground station, so that the ground station adjusts the clock based on the received clock error estimation value, thereby achieving inter-satellite and / or satellite-to-ground time synchronization of the satellite system.

[0012] In some embodiments, before performing a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair in the satellite system and the clock error solution results of each inter-satellite observation pair to obtain the joint clock error estimation result, the method further includes: monitoring the clock values ​​of satellites and / or ground stations in the satellite system; if the deviation between the clock value and the reference value is greater than the deviation threshold, obtaining the clock error solution results of each satellite-to-ground observation pair in the satellite system and the clock error solution results of each inter-satellite observation pair.

[0013] In some embodiments, obtaining the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system includes: obtaining real-time two-way ranging data of each satellite-to-ground observation pair and the real-time two-way ranging data of each inter-satellite observation pair in the satellite system; performing clock error solution on the satellite-to-ground observation pair according to the real-time two-way ranging data of the satellite-to-ground observation pair to obtain the clock error solution results of the satellite-to-ground observation pair; performing clock error solution on the inter-satellite observation pair according to the real-time two-way ranging data of the inter-satellite observation pair to obtain the clock error solution results of the inter-satellite observation pair.

[0014] On the other hand, an embodiment of the present application provides a satellite system time synchronization device, including: a calculation module, used to perform a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair of the satellite system and the clock error solution results of each inter-satellite observation pair, to obtain a joint clock error estimation result, wherein each of the satellite-to-ground observation pairs is an observation combination consisting of a ground station and a first satellite, and each of the inter-satellite observation pairs is an observation combination consisting of a second satellite and one of the first satellites or another second satellite; a sending module, used to send the joint clock error estimation result, so that the satellite system is time synchronized.

[0015] An embodiment of the present application further provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described in any of the above embodiments when executing the computer program.

[0016] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described in any of the above embodiments is implemented.

[0017] An embodiment of the present application further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the method described in any of the above embodiments is implemented.

[0018] The satellite system time synchronization method and apparatus provided in the embodiments of the present application perform a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system, thereby obtaining a joint clock error estimation result. Each satellite-to-ground observation pair is an observation combination consisting of a ground station and a first satellite, and each inter-satellite observation pair is an observation combination consisting of a second satellite and one of the first satellites or another second satellite. The joint clock error estimation result is transmitted to synchronize the satellite system. In this way, by integrating the time synchronization data of the satellite-to-ground observation pairs and the inter-satellite observation pairs and performing a joint clock error estimation, the cumulative error problem that may be caused by local synchronization is resolved, thereby ensuring the consistency of the satellite system's time reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0020] Figure 1 This is a flowchart of a satellite system time synchronization method provided in one embodiment of the present application.

[0021] Figure 2 This is a schematic structural diagram of a satellite system provided in one embodiment of the present application.

[0022] Figure 3 This is a partial flow chart of a satellite system time synchronization method provided in one embodiment of the present application.

[0023] Figure 4 This is a partial flow chart of a satellite system time synchronization method provided in one embodiment of the present application.

[0024] Figure 5 This is a partial flow chart of a satellite system time synchronization method provided in one embodiment of the present application.

[0025] Figure 6 This is a partial flow chart of a satellite system time synchronization method provided in one embodiment of the present application.

[0026] Figure 7 This is a structural diagram of a satellite system time synchronization device proposed in one embodiment of the present application.

[0027] Figure 8 This is a schematic diagram of the physical structure of an electronic device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0028] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clearly understood, the embodiments of the present application are further described in detail below with reference to the accompanying drawings. The illustrative embodiments of the present application and their descriptions are used to explain the present application but are not intended to limit the present application. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application can be arranged in any order.

[0029] The terms “first,” “second,” etc. used herein do not specifically refer to an order or sequence, nor are they intended to limit this application. They are merely used to distinguish elements or operations described with the same technical terms.

[0030] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0031] As used herein, "and / or" includes any and all permutations of the items described.

[0032] The execution subject of the satellite system time synchronization method provided in the embodiment of the present application includes but is not limited to a computer.

[0033] In order to better understand this application, the research background of this application is first described in detail below.

[0034] A method currently exists for achieving full network time synchronization for low-orbit satellite systems using a two-way time comparison algorithm. This approach addresses the problem of achieving self-organizing time synchronization when external timing signals such as GPS or Beidou are unavailable. This approach utilizes a time synchronization frame to transmit nanosecond-level time accuracy across both the satellite-to-ground and inter-satellite links, ensuring accurate synchronization of the low-orbit satellite system while also enabling inter-satellite time synchronization even when ground communication is lacking. However, this approach presents several challenges: inter-satellite synchronization relies on a hop-by-hop approach, which becomes inefficient as the size of the satellite constellation increases, potentially limiting the system's time synchronization speed, particularly in large-scale constellation management. The synchronization process requires multiple repetitions to ensure accuracy, increasing communication overhead and processing complexity, impacting the overall operational efficiency of the system. Furthermore, when the satellite and ground are not visible, time synchronization relies on the stability of the inter-satellite link. If this link fails, the reliability of the system's time synchronization may be compromised.

[0035] In order to solve the above technical problems, Figure 1 FIG. 1 is a flow chart of a satellite system time synchronization method provided by an embodiment of the present application. Figure 1 As shown, the satellite system time synchronization method provided by the embodiment of the present application includes:

[0036] S1. Performing a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system to obtain a joint clock error estimation result, wherein each satellite-to-ground observation pair is an observation combination consisting of a ground station and a first satellite, and each inter-satellite observation pair is an observation combination consisting of a second satellite and one of the first satellites or another second satellite;

[0037] In step S1, the satellite system includes a ground station and a satellite, and the ground station and the satellite work together to achieve a specific function; for example, Figure 2 The satellite system shown includes ground stations R1, R2 and satellite S 1 、S 2 、S 3 、S 4 Among them, the satellite-ground observation pair refers to the observation combination consisting of a ground station and a satellite, and the inter-satellite observation pair refers to the observation combination consisting of a satellite and a satellite. The satellites in the satellite system can be classified, and the satellites belonging to the first category are called first satellites, and the satellites belonging to the second category are called second satellites.

[0038] The first satellite is paired with a ground station to form a satellite-to-ground observation pair, and the second satellite is paired with the first satellite or another second satellite to form an inter-satellite observation pair. The clock error solution for each satellite-to-ground observation pair can be obtained based on the bidirectional satellite-to-ground measurement data from the first satellite and the ground station that constitute the satellite-to-ground observation pair. Similarly, the clock error solution for each inter-satellite observation pair can be obtained based on the bidirectional inter-satellite measurement data from the two satellites that constitute the inter-satellite observation pair.

[0039] After obtaining the clock error solution results for each satellite-ground observation pair and each inter-satellite observation pair in the satellite system, a joint clock error estimation is performed by combining the clock error solution results for the satellite-ground observation pair and the inter-satellite observation pair to obtain a joint clock error estimation result. The joint clock error estimation result may include clock error estimates for each ground station and / or satellite in the satellite system.

[0040] S2. Send the joint clock error estimation result to enable the satellite system to perform time synchronization.

[0041] In step S2, the joint clock error estimation result can be sent to each ground station and / or satellite of the satellite system. For example, when the joint clock error estimation result includes the clock error estimation values ​​of each ground station and / or satellite of the satellite system, the clock error estimation values ​​of each ground station and / or satellite are sent to the corresponding ground station and / or satellite respectively, so that the corresponding ground station and / or satellite adjusts its own clock based on the received clock error estimation value. At this point, the inter-satellite and / or satellite-to-ground time synchronization of the satellite system is achieved.

[0042] The satellite system time synchronization method provided in an embodiment of the present application performs a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system, thereby obtaining a joint clock error estimation result. Each satellite-to-ground observation pair is an observation combination consisting of a ground station and a first satellite, and each inter-satellite observation pair is an observation combination consisting of a second satellite and one of the first satellites or another second satellite. The joint clock error estimation result is transmitted to synchronize the satellite system. In this way, by integrating the time synchronization data of the satellite-to-ground observation pairs and the inter-satellite observation pairs and performing a joint clock error estimation, the cumulative error problem that may be caused by local synchronization is resolved, thereby ensuring the consistency of the satellite system's time reference.

[0043] In some embodiments, a direct communication link is configured between the first satellite and at least one ground station of the satellite system, and no direct communication link is configured between the second satellite and the ground station of the satellite system. Figure 2 As shown, satellite S 1 There are direct communication links between satellite S and ground stations R1 and R2. 2 There is a direct communication link with the ground station R2, so Figure 2 In the satellite system shown, satellite S 1 、S 2 are the first satellites respectively. Figure 2 As shown, satellite S 3 、S 4 There is no direct communication link between satellite S and ground stations R1 and R2. 3 、S 4 The second satellite respectively.

[0044] In some embodiments, a direct communication link is configured between a first satellite forming a satellite-to-ground observation pair and a ground station; a direct communication link is configured between a second satellite forming an inter-satellite observation pair and the first satellite; and a direct communication link is configured between two second satellites forming an inter-satellite observation pair. Specifically, in the satellite system, a satellite-to-ground observation pair can be formed between a first satellite with a direct communication link and a ground station. For a second satellite not having a direct communication link with the ground station, other satellites with direct communication links are configured with the second satellite to form an inter-satellite observation pair. This eliminates the accumulation of errors during intermediate hops and reduces reliance on intermediate nodes / networks when performing time synchronization, compared to observation pairs without direct communication links.

[0045] For example, if Figure 2 As shown, satellite S 1 Together with the ground station R1, it forms a satellite-to-earth observation pair S 1 R1, Satellite S1 Together with the ground station R2, it forms a satellite-to-ground observation pair S 1 R2, Satellite S 2 Together with the ground station R2, it forms a satellite-to-ground observation pair S 2 R2; thus we get three satellite-ground observation pairs S 1 R1, S 1 R2, S 2 R2; In addition, satellite S 3 With satellite S 4 Form an intersatellite observation pair S 3 S 4 , satellite S 3 With satellite S 2 Form an intersatellite observation pair S 3 S 2 , thus we get two intersatellite observation pairs S 3 S 4 、S 3 S 2 .

[0046] like Figure 3 As shown, in some embodiments, the above step S1 may specifically include:

[0047] S11. Selecting a clock from a ground station, a first satellite, and a second satellite in the satellite system as a reference clock;

[0048] In step S11, a satellite or a ground station clock may be selected in the satellite system as a reference clock, and it is assumed that the clock error is 0, or the value relative to GPS time is known.

[0049] S12. Perform a joint clock error estimation relative to the reference clock based on the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system to obtain a joint clock error estimation result.

[0050] In step S12, after the reference clock is selected, the clock errors of other satellites or ground stations in the satellite system will be estimated relative to the reference clock.

[0051] In some embodiments, the above-mentioned step S12 may specifically include: performing a joint clock error estimation relative to the reference clock based on the clock error observation values, clock error standard deviations of each satellite-to-ground observation pair of the satellite system and the clock error observation values, clock error standard deviations of each inter-satellite observation pair to obtain a joint clock error estimation result.

[0052] Specifically, each satellite-ground observation pair The clock error calculation results can include the clock error observation value and the clock error standard deviation. Specifically, for each satellite-ground observation pair Perform time synchronization and obtain satellite and ground stations The clock difference between , and get satellite and ground stations Standard deviation of clock difference .For example, Figure 1 In the satellite system shown in the figure, the satellite-ground observation pair can be calculated. The clock difference observation value and the standard deviation of the clock error , wherein the standard deviation of the clock error observation value of each satellite-ground observation pair (clock error standard deviation) is calculated based on the clock error observation value of each satellite-ground observation pair.

[0053] Similarly, each interstellar observation pair The clock error solution results can include clock error observation value and clock error standard deviation. Specifically, all inter-satellite observation pairs can be synchronized to obtain the satellite and satellite The clock difference between , and get satellite and satellite Standard deviation of clock difference .For example, Figure 2 In the satellite system shown in the figure, the intersatellite observation pair can be calculated. The clock difference observation value and the standard deviation of the clock error , wherein the standard deviation of the clock error observation value of each inter-satellite observation pair (clock error standard deviation) is calculated based on the clock error observation value of each inter-satellite observation pair.

[0054] like Figure 4 As shown, in some embodiments, performing a joint clock error estimation relative to the reference clock based on the clock error observation values ​​and clock error standard deviations of each satellite-to-ground observation pair of the satellite system and the clock error observation values ​​and clock error standard deviations of each inter-satellite observation pair to obtain a joint clock error estimation result may specifically include:

[0055] S121. Constructing a clock error observation vector based on the clock error observation values ​​of each satellite-ground observation pair and the clock error observation values ​​of each inter-satellite observation pair in the satellite system;

[0056] In step S121, the clock error observation vector Contains the clock error observation values ​​of each satellite-ground observation pair and the clock error observation values ​​of each inter-satellite observation pair:

[0057]

[0058] in:

[0059] Indicates satellite and ground stations The clock difference observation between

[0060] Indicates satellite and satellite The clock difference between the observations.

[0061] For example, for Figure 1 In the satellite system shown in Figure 1, the clock error observation vector It can be expressed as:

[0062] .

[0063] S122, constructing a weight matrix according to the clock error standard deviations of each satellite-to-ground observation pair and the clock error standard deviations of each inter-satellite observation pair;

[0064] In step S122, the weight matrix It can be a diagonal matrix, and the diagonal elements are the weights corresponding to the clock error observations. For each satellite-ground observation pair, the weight corresponding to the clock error observation value of the satellite-ground observation pair can be determined based on the clock error standard deviation of the satellite-ground observation pair. Similarly, for each inter-satellite observation pair, the weight corresponding to the clock error observation value of the inter-satellite observation pair can be determined based on the clock error standard deviation of the inter-satellite observation pair. Accordingly, the weight matrix It can be expressed as:

[0065]

[0066] in:

[0067] It is a satellite-ground observation pair The weight corresponding to the clock difference observation value;

[0068] It is an interstellar observation pair The weight corresponding to the clock difference observation.

[0069] For example, for Figure 1 The satellite system shown, the weight matrix It can be expressed as:

[0070] .

[0071] S123. Construct a design matrix according to the link establishment relationship between the first satellite and the ground station in each satellite-to-ground observation pair and the link establishment relationship between the second satellite and the first satellite or another second satellite in each inter-satellite observation pair;

[0072] In step S123, the design matrix It is used to represent the satellite-to-ground or inter-satellite link relationship, which can be expressed as:

[0073]

[0074] Among them, each column corresponds to a satellite or ground station, and each row represents the link relationship between satellite and ground station, and between satellites. Satellite-to-ground observation corresponds to "+1 (satellite) / -1 (ground station)", and inter-satellite observation corresponds to "+1 (transmitter) / -1 (receiver)": If the observation involves satellite-to-ground synchronization, the relevant ground station (reference clock) does not participate in the estimation; if the observation involves inter-satellite synchronization, columns related to the two satellites will appear in the design matrix.

[0075] S124. Perform a joint clock error estimation relative to the reference clock based on the clock error observation vector, weight matrix and design matrix to obtain a joint clock error estimation result, wherein the joint clock error estimation result includes the clock error estimation value of at least one of the following relative to the reference clock: the first satellite, the second satellite, and the ground station.

[0076] In step S124, the least squares method can be used:

[0077]

[0078] The joint clock error estimation result is calculated , joint clock error estimation results The clock error estimates for each satellite and each ground station are included in the vector. These clock error estimates are relative differences to the reference clock. For example, if the ground station is not involved in the estimation, the vector The specific expression can be as follows:

[0079]

[0080] in, Indicates satellite Relative to the reference clock (satellite ) is the estimated value of the clock error.

[0081] like :Indicates satellite The clock is faster than the reference clock by Second;

[0082] like :Indicates satellite The clock is slower than the reference clock by a specific time Second;

[0083] like :Indicates satellite The clock is fully synchronized with the reference clock.

[0084] In some embodiments, the above-mentioned step S2 may specifically include: sending the clock error estimate value to the corresponding satellite, so that the satellite adjusts the clock based on the received clock error estimate value, thereby achieving inter-satellite and / or satellite-to-ground time synchronization of the satellite system; and / or, sending the clock error estimate value to the corresponding ground station, so that the ground station adjusts the clock based on the received clock error estimate value, thereby achieving inter-satellite and / or satellite-to-ground time synchronization of the satellite system.

[0085] Specifically, in order to achieve high-precision time synchronization of the satellite system, it is necessary to adjust the clocks of each satellite and / or ground station based on the clock error estimation results. Taking satellites as an example, the specific process can be as follows:

[0086] The results can be estimated from the joint clock error Read the clock error of each satellite relative to the reference clock , and then the clock difference The signals are sent to the corresponding satellites respectively, so that the corresponding satellites adjust their local clocks based on the received clock errors. The clock error adjustment principles are as follows:

[0087] if , then the satellite The clock is faster than the reference clock and needs to be dialed back. Second;

[0088] if , then the satellite The clock is slower than the reference clock and needs to be adjusted forward. Second;

[0089] if , then the satellite The clock is synchronized with the reference clock and no adjustment is required.

[0090] After adjustment, the clocks of each satellite will be synchronized with the reference clock. At this time, the clock synchronization status of the satellites in the entire satellite system is as follows:

[0091]

[0092] This means that the clock difference errors between all satellite clocks in the satellite system are close to zero, which is minimized.

[0093] The clock adjustment process for the ground station is similar to the clock adjustment process for the satellite described above and will not be repeated here.

[0094] like Figure 5 As shown, in some embodiments, before the above step S1, the method may further include:

[0095] S01. Monitoring clock values ​​of satellites and / or ground stations in a satellite system;

[0096] In step S01, a monitoring strategy for the satellite system may be set to monitor the clock values ​​of satellites and / or ground stations in the satellite system in real time.

[0097] S02. If the deviation between the clock value and the reference value is greater than the deviation threshold, the clock error calculation results of each satellite-to-ground observation pair and the clock error calculation results of each inter-satellite observation pair of the satellite system are obtained.

[0098] In step S02, when new monitoring data reveals that the time deviation of one or more satellites / ground stations has changed significantly, the time synchronization process can be quickly started. Specifically, a time deviation threshold can be defined. ,when When , the resynchronization process is triggered, where Indicates the clock reference value (or can be called the correct clock value), Indicates the monitored clock value.

[0099] like Figure 6 As shown, in some embodiments, obtaining the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair of the satellite system includes:

[0100] S021. Acquire real-time two-way ranging data of each satellite-to-ground observation pair and real-time two-way ranging data of each inter-satellite observation pair in the satellite system;

[0101] In step S021, two-way ranging is performed between the satellite of each satellite-to-ground observation pair and the ground station to obtain two-way ranging data. Similarly, two-way ranging is performed between the two satellites of each inter-satellite observation pair to obtain two-way ranging data.

[0102] S022. Calculate the clock difference of the satellite-ground observation pair based on the real-time two-way ranging data of the satellite-ground observation pair to obtain a clock difference calculation result of the satellite-ground observation pair;

[0103] In step S022, for each satellite-ground observation pair, based on the two-way ranging data of the satellite-ground observation pair, the clock difference between the satellite and the ground station constituting the satellite-ground observation pair is solved to obtain the clock difference solution result of the satellite-ground observation pair.

[0104] S023. Perform clock error calculation on the inter-satellite observation pair according to the real-time two-way ranging data of the inter-satellite observation pair to obtain a clock error calculation result of the inter-satellite observation pair.

[0105] In step S023, for each inter-satellite observation pair, based on the two-way ranging data of the inter-satellite observation pair, the clock difference between the two satellites constituting the inter-satellite observation pair is solved to obtain the clock difference solution result of the inter-satellite observation pair.

[0106] It should be noted that this embodiment does not limit the execution order between the above-mentioned step S022 and step S033. Step S022 can be executed before step S033, or after step S033, or simultaneously with step S033.

[0107] To better understand this application, Figure 2 Taking the satellite system shown as an example, the satellite system time synchronization method provided in the embodiment of the present application is described in detail.

[0108] Step 1: Synchronize satellite and ground time.

[0109] Sub-step 1.1: Obtain all visible ground station-satellite observation pairs (satellite-ground observation pairs) based on the ground station and satellite spatial coordinates ,in, Indicates the number satellite, Indicates the number For example, Figure 2 In the satellite system shown, the visible ground station-satellite observation pairs are .

[0110] Sub-step 1.2: For each visible ground station-satellite observation pair Perform time synchronization and obtain synchronization results , Indicates satellite and ground stations The clock difference observations between and get the clock difference standard deviation, Indicates satellite and ground stations The standard deviation of the clock difference observations between . For example, Figure 2 In the satellite system shown in the figure, the visible ground station-satellite observation pair can be solved The clock difference observation value and the standard deviation of the clock error .

[0111] Step 2: Inter-satellite time synchronization.

[0112] Sub-step 2.1: Search for satellites in the constellation that do not have a direct communication link with the ground station (also known as out-of-view satellites) For example, Figure 2 Satellite and satellite There is no direct communication link with the ground station, so the search results for exo-satellites are considered .

[0113] Sub-step 2.2: Search for all satellite-satellite pairs that can establish direct line of sight with the out-of-view satellite (intersatellite observation pairs) For example, Figure 2 The satellite system in the satellite-satellite pair search results are .

[0114] Sub-step 2.3: Synchronize all satellite-satellite pairs to obtain the synchronized clock error results , indicating the extra-visual satellite and satellite The clock difference observations between the two and the standard deviation of the clock difference are obtained , indicating satellite and satellite The standard deviation of the clock difference observations between . Figure 2 The satellite system shown in can be solved to obtain the satellite-satellite observation pair The clock difference observation value and the standard deviation of the clock error .

[0115] Step 3: Perform joint observation processing based on the time synchronization results.

[0116] In step 3, the goal is to perform joint time synchronization for the entire constellation using the weighted least squares method based on the known satellite-ground and inter-satellite time synchronization results, eliminating the deviation caused by measurement errors and thus achieving high-precision time synchronization for the entire constellation.

[0117] Sub-step 3.1: Basic formula of weighted least squares method

[0118] When performing weighted least squares estimation, a single satellite or ground station in the satellite network is selected as a reference clock. Its clock error is assumed to be zero, or its value relative to GPS time is known. The clock errors of all other satellites and ground stations are estimated relative to this reference clock. Therefore, the reference clock's clock error is fixed at a known value, and the remaining clock errors are estimated using the least squares method.

[0119] The objective function of the weighted least squares method is:

[0120]

[0121] in: Represents the clock difference observation value of each observation pair (satellite-ground or inter-satellite); represents the estimated clock error relative to the reference clock (estimated clock error value); is the weight of the observation, defined as ,in is the standard deviation of the corresponding clock error observation.

[0122] Sub-step 3.2: Setting the reference clock

[0123] Select a satellite or ground station clock as the reference clock and assume that its clock error is 0, that is, , or its clock error relative to GPS time is known. In this case, the reference clock is not used in the estimation, and the clock errors of the remaining clocks are estimated as differences relative to the reference clock.

[0124] For example, assuming that ground station R1 is selected as the reference clock, then , the clock bias estimates for all other ground stations and satellites ( ), is the estimated value relative to ground station R1.

[0125] Sub-step 3.3: Formula for calculating clock error estimate

[0126] By selecting the reference clock, the design matrix (also called the design matrix) for the joint observation process can be simplified. The clock error estimate is derived using the following matrix form of the weighted least squares method:

[0127]

[0128] in: represents the clock error vector relative to the reference clock that needs to be estimated; represents a design matrix constructed based on a linking relationship between the first satellite and the ground station in each of the satellite-to-ground observation pairs and a linking relationship between the second satellite and the first satellite or another second satellite in each of the inter-satellite observation pairs; is the weight matrix, and the diagonal elements are , , is the standard deviation of the corresponding clock error observation; is the clock error observation vector, which includes the clock error observations obtained by satellite-ground synchronization and inter-satellite synchronization.

[0129] Sub-step 3.4: Setting clock error weights

[0130] The formula for setting the clock error weight should be expressed as:

[0131]

[0132] Special, for Figure 2 For the satellite system in [1], consider the following satellite-ground and inter-satellite observation pairs:

[0133] Satellite-ground synchronous observation pair:

[0134] Clock error observations , standard deviation of clock error ;

[0135] Clock error observations , standard deviation of clock error ;

[0136] Clock error observations , standard deviation of clock error ;

[0137] Intersatellite synchronous observation pair:

[0138] Clock error observations , standard deviation of clock error ;

[0139] Clock error observations , standard deviation of clock error .

[0140] For these clock error observations, the weights are:

[0141]

[0142] Sub-step 3.5: Joint estimation process of clock errors

[0143] 1. Constructing a clock error observation vector :

[0144] Clock error observation vector Contains all satellite-ground and inter-satellite clock error observations:

[0145]

[0146] in: Indicates satellite and ground stations Observed values ​​of satellite-to-ground clock difference;

[0147] Indicates satellite and satellite The inter-satellite clock difference observations between .

[0148] For example, for Figure 2 The satellite system in the clock error observation vector Expressed as:

[0149] .

[0150] 2. Constructing the weight matrix :

[0151] Weight Matrix is a diagonal matrix, and the diagonal elements are the weights corresponding to the clock error observations:

[0152]

[0153] in:

[0154] is the weight of the satellite-ground synchronous clock difference observation value;

[0155] is the weight of the inter-satellite synchronous clock error observation.

[0156] For example, for Figure 2 The satellite system in the weight matrix Expressed as:

[0157]

[0158] 3. Build a design matrix :

[0159] Design Matrix Represents the relationship between the clock error observation value and the actual clock error of each satellite and ground station, and the design matrix It can be expressed as:

[0160]

[0161] Among them, each column corresponds to a satellite or ground station, and each row represents the link relationship between satellite and ground station, and between satellites. Satellite-to-ground observation corresponds to "+1 (satellite) / -1 (ground station)", and inter-satellite observation corresponds to "+1 (transmitter) / -1 (receiver)": If the observation involves satellite-to-ground synchronization, the relevant ground station (reference clock) does not participate in the estimation; if the observation involves inter-satellite synchronization, columns related to the two satellites will appear in the design matrix.

[0162] For example, for Figure 2 In the satellite system, since the clock of ground station R1 is used as the reference clock, the clock error of ground station R1 is known ( ), so the columns related to R1 can be omitted from the design matrix, which can be expressed as:

[0163]

[0164] Since the clock of ground station R1 is used as the reference clock, the above matrix H is the matrix generated after omitting the columns related to R1. The original matrix is:

[0165]

[0166] Among them, each column from left to right represents S 1、S 2 、S 3 、S 4 , R1, R2, the first row indicates that the ground station-satellite observation pair in step 1 has S 1 R1 (+1 (S 1 ) / -1(R1)), the second row indicates that the ground station-satellite observation pair in step 1 has S 1 R2 (+1 (S 1 ) / -1(R2)), the third row indicates that the ground station-satellite observation pair in step 1 has S 2 R2 (+1 (S 2 ) / -1(R2)), the fourth row indicates that the satellite-satellite observation pair in step 2 has S 2 S 3 (+1(S 2 ) / -1(S 3 )), the fifth row indicates that the satellite-satellite observation pairs in step 2 have S 3 S 4 (+1(S 3 ) / -1(S 4 )).

[0167] 4. Joint clock error estimation:

[0168] By the least squares formula:

[0169]

[0170] Calculate the estimated clock errors of all satellites , these clock differences are relative to the reference clock ( ) relative differences.

[0171] Step 4: Final output of joint clock error estimation and time synchronization adjustment

[0172] Sub-step 4.1: Presentation of Joint Clock Error Estimates

[0173] Since the reference clock (such as the ground station ) is 0, the joint clock error estimation result will show the clock error of each non-reference clock relative to the reference clock.

[0174] The final output of the joint clock error estimation result is as follows:

[0175]

[0176] in, Indicates ground station Relative to the reference clock ( ), Indicates satellite Relative to the reference clock ( ) is the estimated value of the clock error.

[0177] Sub-step 4.2: Physical meaning of clock error estimation results

[0178] Take the satellite clock error estimate as an example:

[0179] :Indicates satellite The clock is faster than the reference clock by Second;

[0180] :Indicates satellite The clock is slower than the reference clock by a specific time Second;

[0181] :Indicates satellite The clock is fully synchronized with the reference clock;

[0182] The same applies to the estimated clock error of the ground station.

[0183] These clock error estimates indicate how each satellite or ground station clock differs from a reference clock.

[0184] Sub-step 4.3: Use clock error estimation results to adjust time synchronization

[0185] In order to achieve high-precision time synchronization for the entire constellation, it is necessary to correct the clock of each satellite based on the clock error estimation results. The adjustment steps are as follows:

[0186] 1. Principles of Clock Correction

[0187] if , then the satellite The clock is faster than the reference clock and needs to be dialed back. Second;

[0188] if , then the satellite The clock is slower than the reference clock and needs to be adjusted forward. Second;

[0189] if , then the satellite The clock is synchronized with the reference clock and no adjustment is required.

[0190] 2. Adjustment process

[0191] Read clock error: From the clock error vector Read the clock error of each satellite or ground station relative to the reference clock .

[0192] Calculate the adjustment amount: Based on the clock error result , calculate the clock correction amount that needs to be adjusted:

[0193] for In this case, the clock needs to be turned back;

[0194] for In this case, the clock needs to be set forward.

[0195] Perform clock adjustment: For each satellite , adjust its local clock, the specific operation is to dial back or forward the clock.

[0196] 3. Adjusted synchronization status

[0197] After adjustment, the clocks of all satellites and ground stations will be aligned with the reference clock ( ) synchronization, the clock synchronization status of the entire constellation is as follows:

[0198]

[0199] This means that the clock difference errors between all clocks in the network are close to zero, which is minimized.

[0200] Step 5: Feedback mechanism and dynamic adjustment.

[0201] Sub-step 5.1: After time synchronization is completed, dynamically adjust the constellation's time synchronization strategy based on feedback from real-time observation data. For example, when new observation data reveals that the time deviation of some satellites has changed significantly, the synchronization process can be quickly restarted to ensure the continued accuracy of time synchronization. A time deviation threshold can be defined. ,when , triggers the resynchronization process.

[0202] Through the above process, the time synchronization of the entire constellation can be completed. Specifically,

[0203] Satellite-ground synchronization: Time synchronization between the ground station and the satellites within its visual range;

[0204] Intersatellite synchronization: The extrasatellite satellite is synchronized with other satellites through intersatellite links;

[0205] Joint synchronization: Based on the results of weighted least squares processing, all satellite clocks are adjusted relative to the reference clock, ultimately achieving high-precision time synchronization for the entire constellation.

[0206] After the adjustment is completed, the time synchronization error of the entire constellation is minimized, and the clock errors between satellites or ground stations are optimally synchronized within the measurement error range.

[0207] As can be seen, the satellite system time synchronization method provided in the embodiments of the present application combines satellite-to-ground and inter-satellite observations for joint time synchronization, solving the problem of high-precision time synchronization when satellites cannot directly communicate with ground stations. By utilizing inter-satellite communication links and a joint estimation algorithm, high-precision time synchronization is achieved for the entire constellation, making it particularly suitable for the management and control of low-orbit satellite constellations. By constructing a joint observation equation system for joint clock error estimation, the problem of integrating satellite-to-ground and inter-satellite observation data is solved, achieving the effect of fully utilizing all available observation information. By adopting a weighted processing mechanism based on observation accuracy, the problem of different observation data quality differences is solved, achieving the effect of optimizing overall synchronization accuracy. By using the iterative solution of the weighted least squares method, the difficulty of solving large-scale time synchronization problems is solved, achieving the effect of efficiently and accurately estimating the clock biases of all satellites. By adopting a dynamic adjustment mechanism, the problem of reduced synchronization accuracy caused by satellite clock drift is solved, achieving the effect of maintaining long-term stable and high-precision time synchronization. By adopting a global time synchronization correction method, the problem of cumulative errors that may be caused by local synchronization is solved, achieving the effect of ensuring the consistency of the time base of the entire constellation system.

[0208] Figure 7 This is a schematic diagram of the structure of a satellite system time synchronization device proposed in one embodiment of the present application. Figure 7 As shown, a satellite system time synchronization device proposed in an embodiment of the present application includes:

[0209] a calculation module 21 configured to perform a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system, to obtain a joint clock error estimation result, wherein each satellite-to-ground observation pair is an observation combination consisting of a ground station and a first satellite, and each inter-satellite observation pair is an observation combination consisting of a second satellite and one of the first satellites or another second satellite;

[0210] The sending module 22 is used to send the joint clock error estimation result to enable the satellite system to perform time synchronization.

[0211] The satellite system time synchronization device provided in an embodiment of the present application performs a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system, thereby obtaining a joint clock error estimation result. Each satellite-to-ground observation pair is an observation combination consisting of a ground station and a first satellite, and each inter-satellite observation pair is an observation combination consisting of a second satellite and one of the first satellites or another second satellite. The joint clock error estimation result is transmitted to synchronize the satellite system. In this way, by integrating the time synchronization data of the satellite-to-ground observation pair and the inter-satellite observation pair and performing a joint clock error estimation, the cumulative error problem that may be caused by local synchronization is resolved, thereby ensuring the consistency of the satellite system's time reference.

[0212] The embodiments of the apparatus provided in the embodiments of the present application can be specifically used to execute the processing flow of the above-mentioned embodiments of the satellite system time synchronization method. Its functions are not described in detail here, and reference can be made to the detailed description of the above-mentioned method embodiments.

[0213] Figure 8 A schematic diagram of the physical structure of an electronic device provided in an embodiment of the present application is shown in FIG. Figure 8 As shown, the electronic device may include: a processor 301, a communication interface 302, a memory 303, and a communication bus 304, wherein the processor 301, the communication interface 302, and the memory 303 communicate with each other via the communication bus 304. The processor 301 may call the logic instructions in the memory 303 to execute the method described in any of the above embodiments.

[0214] In addition, the logical instructions in the above-mentioned memory 303 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application, or the part that contributes to the existing technology, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program code.

[0215] This embodiment discloses a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the methods provided by the above-mentioned method embodiments.

[0216] This embodiment provides a computer-readable storage medium, which stores a computer program. The computer program enables the computer to execute the methods provided by the above method embodiments.

[0217] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0218] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0219] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0220] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1The steps for the function specified in one or more boxes.

[0221] In the description of this specification, reference to the terms "one embodiment," "a specific embodiment," "some embodiments," "for example," "example," "specific example," or "some examples" 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 application. 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 appropriate manner in any one or more embodiments or examples.

[0222] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A satellite system time synchronization method, characterized in that: include: Performing a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system to obtain a joint clock error estimation result, wherein each satellite-to-ground observation pair is an observation combination consisting of a ground station and a first satellite, and each inter-satellite observation pair is an observation combination consisting of a second satellite and one of the first satellites or another second satellite; The joint clock error estimation result is sent to enable the satellite system to perform time synchronization.

2. The method according to claim 1, characterized in that A direct communication link is configured between the first satellite and at least one ground station of the satellite system, and no direct communication link is configured between the second satellite and the ground station of the satellite system.

3. The method according to claim 2, characterized in that A direct communication link is configured between the first satellite and the ground station constituting a satellite earth observation pair; A direct communication link is configured between the second satellite and the first satellite constituting an inter-satellite observation pair; A direct communication link is configured between the two second satellites forming an inter-satellite observation pair.

4. The method according to any one of claims 1 to 3, characterized in that The performing of joint clock error estimation based on the clock error solution results of each satellite-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system to obtain the joint clock error estimation result includes: selecting a clock of one of a ground station, a first satellite, and a second satellite in the satellite system as a reference clock; Based on the clock error solution results of each satellite-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system, a joint clock error estimation relative to the reference clock is performed to obtain a joint clock error estimation result.

5. The method according to claim 4, characterized in that The step of performing a joint clock error estimation relative to the reference clock based on the clock error solution results of each satellite-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system to obtain a joint clock error estimation result includes: Based on the clock error observation values ​​and clock error standard deviations of each satellite-to-ground observation pair of the satellite system and the clock error observation values ​​and clock error standard deviations of each inter-satellite observation pair, a joint clock error estimation relative to the reference clock is performed to obtain a joint clock error estimation result.

6. The method according to claim 5, characterized in that The step of performing a joint clock error estimation relative to the reference clock based on the clock error observation values ​​and clock error standard deviations of each satellite-ground observation pair and the clock error observation values ​​and clock error standard deviations of each inter-satellite observation pair in the satellite system to obtain a joint clock error estimation result includes: Constructing a clock error observation vector based on the clock error observation values ​​of each satellite-ground observation pair and the clock error observation values ​​of each inter-satellite observation pair of the satellite system; Constructing a weight matrix according to the clock error standard deviations of each satellite-ground observation pair and the clock error standard deviations of each inter-satellite observation pair; constructing a design matrix according to the link establishment relationship between the first satellite and the ground station in each of the satellite-to-ground observation pairs and the link establishment relationship between the second satellite and the first satellite or another second satellite in each of the inter-satellite observation pairs; According to the clock error observation vector, weight matrix and design matrix, a joint clock error estimation is performed relative to the reference clock to obtain a joint clock error estimation result, wherein the joint clock error estimation result includes the clock error estimation value of at least one of the following relative to the reference clock: the first satellite, the second satellite, and the ground station.

7. The method according to claim 6, characterized in that The sending of the joint clock error estimation result so that the satellite system performs time synchronization includes: The clock error estimation value is sent to the corresponding satellite, so that the satellite adjusts the clock based on the received clock error estimation value, thereby achieving inter-satellite and / or satellite-to-ground time synchronization of the satellite system.

8. The method according to claim 6, characterized in that The sending of the joint clock error estimation result so that the satellite system performs time synchronization includes: The clock error estimate is sent to a corresponding ground station, so that the ground station adjusts the clock based on the received clock error estimate, thereby synchronizing the satellite system's inter-satellite and / or satellite-to-ground time.

9. The method according to any one of claims 1 to 3, characterized in that Before performing joint clock error estimation based on the clock error solution results of each satellite-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system to obtain the joint clock error estimation result, the method further includes: Monitoring the clock values ​​of satellites and / or ground stations in satellite systems; If the deviation between the clock value and the reference value is greater than the deviation threshold, the clock error calculation results of each satellite-to-ground observation pair and the clock error calculation results of each inter-satellite observation pair of the satellite system are obtained.

10. The method according to claim 9, characterized in that The obtaining of the clock error calculation results of each satellite-to-ground observation pair and the clock error calculation results of each inter-satellite observation pair of the satellite system includes: Acquiring real-time two-way ranging data of each satellite-to-ground observation pair and real-time two-way ranging data of each inter-satellite observation pair of the satellite system; performing clock error calculation on the satellite-ground observation pair according to the real-time two-way ranging data of the satellite-ground observation pair to obtain a clock error calculation result of the satellite-ground observation pair; The clock error of the inter-satellite observation pair is solved according to the real-time two-way ranging data of the inter-satellite observation pair to obtain the clock error solution result of the inter-satellite observation pair.

11. A satellite system time synchronization device, characterized in that: include: a calculation module, configured to perform a joint clock error estimation based on the clock error solution results of each satellite-to-ground observation pair and the clock error solution results of each inter-satellite observation pair in the satellite system, to obtain a joint clock error estimation result, wherein each satellite-to-ground observation pair is an observation combination consisting of a ground station and a first satellite, and each inter-satellite observation pair is an observation combination consisting of a second satellite and one of the first satellites or another second satellite; The sending module is used to send the joint clock error estimation result so that the satellite system can be time synchronized.

12. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 10 is implemented.

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