CN115623582B - Low-orbit satellite constellation time synchronization method, system, device and medium - Google Patents
Low-orbit satellite constellation time synchronization method, system, device and medium Download PDFInfo
- Publication number
- CN115623582B CN115623582B CN202211637730.3A CN202211637730A CN115623582B CN 115623582 B CN115623582 B CN 115623582B CN 202211637730 A CN202211637730 A CN 202211637730A CN 115623582 B CN115623582 B CN 115623582B
- Authority
- CN
- China
- Prior art keywords
- time
- satellite
- gnss
- value
- current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/001—Synchronization between nodes
- H04W56/002—Mutual synchronization
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18517—Transmission equipment in earth stations
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/18521—Systems of inter linked satellites, i.e. inter satellite service
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/0055—Synchronisation arrangements determining timing error of reception due to propagation delay
- H04W56/006—Synchronisation arrangements determining timing error of reception due to propagation delay using known positions of transmitter and receiver
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Astronomy & Astrophysics (AREA)
- Aviation & Aerospace Engineering (AREA)
- General Physics & Mathematics (AREA)
- Synchronisation In Digital Transmission Systems (AREA)
- Position Fixing By Use Of Radio Waves (AREA)
- Radio Relay Systems (AREA)
Abstract
The application discloses a low earth orbit satellite constellation time synchronization method, a system, a device and a medium, which are applied to the field of aerospace. According to the low earth orbit satellite constellation time synchronization method provided by the application, whether the low earth orbit satellite constellation time synchronization method is a central satellite or not needs to be judged, if yes, the time synchronization frame of the central satellite is actively and periodically sent to an adjacent satellite, and a GNSS synchronization method is adopted to synchronize with GNSS time. If not, receiving the time synchronization frame from the adjacent satellite, sending the time synchronization frame of the current satellite to the rest adjacent satellites, and performing the step of adopting the GNSS synchronization method and the GNSS time synchronization. According to the method, time synchronization between the satellite and the ground can be realized only by at least comprising one GNSS receiver in a plurality of satellites without faults, the satellites are communicated with each other, synchronization between the satellites is realized, the faultless GNSS receiver is adopted again, synchronization with the ground is achieved, and extra requirements on a ground measurement and control station are not required.
Description
Technical Field
The present application relates to the field of aerospace, and in particular, to a method, system, device, and medium for synchronizing a low earth orbit satellite constellation time.
Background
In recent years, some commercial space companies plan to build their own low-orbit satellite constellations, and the common orbiting satellites in the constellations generally have bidirectional or unidirectional inter-satellite communication capability, which makes requirements on inter-satellite time synchronization in the constellations, and currently, the common intra-constellation time synchronization methods mainly include the following 2 types: the scheme 1 completely depends on a GNSS receiver of the satellite to carry out time synchronization, the scheme 2 depends on a ground measurement and control station and a single satellite to adopt a Round Trip Time (RTT) synchronization algorithm to realize the time synchronization of the single satellite and the ground, and then the satellite after the time synchronization adopts the RTT synchronization algorithm through an inter-satellite link and other satellites to realize the time synchronization of the other satellites and the satellite.
However, in the scheme 1, a GNSS receiver has a permanent fault, so that the satellite cannot perform time synchronization with other satellites, the scheme 2 puts extra demands on a ground measurement and control station, and for a constellation with only inter-satellite unidirectional links, an RTT method cannot be adopted to realize an inter-satellite time synchronization function.
In view of the above-mentioned technology, it is an urgent need of those skilled in the art to find a method for achieving inter-satellite time synchronization and ground time synchronization in a constellation by using a GNSS receiver and a unidirectional inter-satellite link when the GNSS receiver of only one of a plurality of satellites is not in failure.
Disclosure of Invention
The application aims to provide a low earth orbit satellite constellation time synchronization method, a system, a device and a medium. When the GNSS receivers in some satellites on the same orbit have faults, the satellite time synchronization is realized when only one GNSS receiver is intact.
In order to solve the above technical problem, the present application provides a method for synchronizing a low earth orbit satellite constellation time, including:
judging whether the satellite is a central satellite;
if so, actively and periodically sending a time synchronization frame of the central satellite to an adjacent satellite, and synchronizing with the GNSS time by adopting a GNSS synchronization method;
if not, receiving the time synchronization frame from the adjacent satellite, sending the time synchronization frame of the current satellite to the other adjacent satellites, and performing the step of synchronizing with the GNSS time by adopting the GNSS synchronization method.
Preferably, if the satellite itself is a central satellite, the transmitting the time synchronization frame of the central satellite to the adjacent satellite includes:
judging whether the timing time is reached;
if the timing time is reached, reading the second value and the microsecond value of the central satellite;
the time synchronization frame of the central satellite is filled.
Preferably, if the satellite itself is not the central satellite, receiving the time synchronization frame from the adjacent satellite includes:
judging whether the high-precision time of the current satellite is effective or not and whether the high-precision time in the time synchronization frame of the adjacent satellite is effective or not;
if the satellite is valid, reading the second value and the microsecond value of the current satellite;
reading the second value and the microsecond value of the adjacent satellite;
obtaining a calibration value according to the second value and the microsecond value of the adjacent satellite and the second value and the microsecond value of the current satellite;
judging whether the high-precision time or the low-precision time of the current satellite is invalid and whether the sub-precision time of the adjacent satellite is valid;
if the satellite is valid, reading the second value and the microsecond value of the adjacent satellite;
obtaining the satellite time of the current satellite according to the second value, the microsecond value and the calibration value of the adjacent satellite;
setting the sub-precision time of the current satellite to be effective.
Preferably, after setting the sub-precision time of the current satellite to be valid, the method further comprises:
judging whether the current satellite is the time synchronization frame of the current satellite to actively launch the satellite;
if not, reading the second value and the microsecond value of the current satellite;
and filling the time synchronization frame of the current satellite.
Preferably, the GNSS synchronization method is used for synchronizing with GNSS time, and includes:
judging whether the rising edge of the PPS sent by the GNSS receiver is detected;
if the fact that the GNSS receiver sends the PPS rising edge is detected, delaying the first time, receiving and analyzing a GNSS telemetering packet;
judging whether the GNSS telemetry packet passes verification and whether the GNSS receiver is effective in positioning;
if the GNSS telemetering packet is not checked or the GNSS receiver is invalid for positioning, adding 1 to the GNSS continuous positioning invalid count, and clearing the GNSS continuous positioning valid count;
if the GNSS telemetry packet passes verification and the GNSS receiver is effectively positioned, judging whether a difference value before and after time in the GNSS telemetry packet is equal to second time or not;
if the difference value before and after the time in the GNSS telemetering packet is not equal to the second time, adding 1 to the GNSS continuous positioning invalid count, and clearing the GNSS continuous positioning valid count;
if the difference value between the time before and after the GNSS telemetering packet is equal to the second time, judging whether the current satellite time is synchronous with the GNSS time and whether the difference value between the current satellite time and the GNSS time is larger than a third time;
if the current satellite time and the GNSS time are synchronous and the difference value of the current satellite time and the GNSS time is more than the third time, setting the high-precision time of the current satellite to be invalid and setting the low-precision time of the current satellite to be invalid;
and if the current satellite time is not synchronous with the GNSS time or the difference value between the current satellite time and the GNSS time is not more than the third time, adding 1 to the GNSS continuous positioning valid count, and clearing the GNSS continuous positioning invalid times.
Preferably, after the GNSS positioning invalid count is increased by 1 and the GNSS positioning valid count is cleared, the method further includes:
judging whether the times of the GNSS continuous positioning invalidity are greater than a first time;
if the number of times is larger than the first number of times, setting the low-precision time of the current satellite to be invalid;
if the number of times of the GNSS continuous positioning invalidation is not more than the first time, judging whether the number of times of the GNSS continuous positioning invalidation is more than the second time or not;
and if the number of times is more than the second number of times, setting the high-precision time of the current satellite to be invalid.
Preferably, after the count of valid GNSS consecutive positions is increased by 1 and the number of invalid GNSS consecutive positions is cleared, the method further includes:
judging whether the effective times of the GNSS continuous positioning are greater than a second time or not;
if the GNSS continuous positioning effective times are larger than the second time, judging whether the absolute value of the time difference between the satellite affair and the GNSS is larger than the fourth time;
if the current satellite time is greater than the fourth time, setting the current satellite time as a time second value in the GNSS telemetry packet;
if the time is not more than the fourth time, judging whether the microsecond value of the current satellite at the PPS moment is more than the fifth time or not;
if the time is not more than the fifth time, adjusting the satellite time according to the first calculation mode;
if the time is longer than the fifth time, the satellite time is adjusted according to a second calculation mode;
setting the high-precision time of the current satellite to be effective;
it is effective to set the low-precision time of the current satellite.
In order to solve the above technical problem, the present application further provides a low earth orbit satellite constellation time synchronization system, including:
the judging module is used for judging whether the satellite is a central satellite;
the transmitting module is used for transmitting the time synchronization frame of the central satellite to the adjacent satellite when the transmitting module is the central satellite, and adopts a GNSS synchronization method to synchronize with the GNSS time;
and the receiving module is used for receiving the time synchronization frame from the adjacent satellite, sending the time synchronization frame of the current satellite to other adjacent satellites when the receiving module is not the central satellite, and performing the step of adopting a GNSS synchronization method and GNSS time synchronization.
In order to solve the above technical problem, the present application further provides a low earth orbit satellite constellation time synchronization apparatus, including a memory for storing a computer program;
a processor for implementing the steps of the method for time synchronization of low earth orbit satellite constellations described above when executing a computer program.
In order to solve the above technical problem, the present application further provides a computer-readable storage medium, on which a computer program is stored, and the computer program, when executed by a processor, implements the steps of the method for synchronizing the time of the low earth orbit satellite constellation.
According to the low earth orbit satellite constellation time synchronization method provided by the application, whether the low earth orbit satellite constellation time synchronization method is a central satellite or not needs to be judged, if yes, a time synchronization frame of the central satellite is sent to an adjacent satellite, and the GNSS synchronization method is adopted to be synchronized with the GNSS time. If not, receiving the time synchronization frame from the adjacent satellite, sending the time synchronization frame of the current satellite to the rest adjacent satellites, and performing the step of adopting a GNSS synchronization method and GNSS time synchronization. The method avoids the defect caused by time synchronization because a single satellite adopts a GNSS receiver and ground communication, and cannot realize time synchronization when the GNSS receiver fails. According to the method, only in numerous satellites, at least one GNSS receiver is contained, time synchronization between the satellites and the ground can be achieved without failure, the satellites are communicated with one another, synchronization between the satellites is achieved, the failure-free GNSS receiver is adopted again, synchronization with the ground is achieved, and extra requirements for a ground measurement and control station are not needed.
Drawings
In order to more clearly illustrate the embodiments of the present application, the drawings needed for the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained by those skilled in the art without inventive effort.
Fig. 1 is a flowchart of a low earth orbit satellite constellation time synchronization method according to an embodiment of the present disclosure;
fig. 2 is a plan view of a low earth orbit satellite constellation provided in an embodiment of the present application;
FIG. 3 is a flowchart illustrating a method for a central satellite to transmit a time synchronization frame of the central satellite to neighboring satellites according to an embodiment of the present invention;
FIG. 4 is a flow chart of an embodiment of the present invention for receiving a time synchronization frame from neighboring satellites;
FIG. 5 is a flowchart illustrating GNSS time synchronization using a GNSS method according to an embodiment of the present invention;
fig. 6 is a block diagram of a low earth orbit satellite constellation time synchronization system according to another embodiment of the present application;
fig. 7 is a block diagram of a low earth orbit satellite constellation time synchronization apparatus according to another embodiment of the present application.
Detailed Description
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 obtained by a person of ordinary skill in the art based on the embodiments in the present application without any creative effort belong to the protection scope of the present application.
The core of the application is to provide a low earth orbit satellite constellation time synchronization method, system, device and medium.
In order that those skilled in the art will better understand the disclosure, the following detailed description is given with reference to the accompanying drawings.
Fig. 1 is a flowchart of a low earth orbit satellite constellation time synchronization method provided in an embodiment of the present application, and as shown in fig. 1, the method includes the following steps.
S10: and judging whether the satellite is the central satellite.
In a specific embodiment, a low-earth satellite constellation generally includes a plurality of orbital planes, and if N satellites are provided on one orbital plane, the N satellites are generally uniformly distributed on the same orbital plane, and if the N satellites can achieve time synchronization and time synchronization with the ground, the satellites on other orbital planes can achieve time synchronization by the same method and time synchronization with the ground, and finally achieve satellite time synchronization in the whole constellation and time synchronization with the ground.
In a specific embodiment, each satellite is equipped with at least an on-board computer, a GNSS receiver and an inter-satellite communicator, an asynchronous RS422 interface and a PPS interface are provided between the on-board computer and the GNSS receiver, and a bidirectional synchronous interface is provided between the on-board computer and the inter-satellite communicator. When the positioning of the GNSS receiver is effective, the GNSS receiver generates a PPS signal (which is a 1ms wide positive pulse) at the time of a whole second, the rising edge of the PPS signal is aligned with the whole second, and the GNSS telemetry packet (containing the positioning state, time, track position and speed information) is actively sent through the asynchronous RS422 at the moment.
The on-board computer of each satellite can realize the time synchronization of the satellite and the GNSS (when the GNSS positioning is effective, the satellite affair and GNSS time synchronization error is less than 10 us) through the GNSS receiver, and the time difference of the GNSS receiver is very small with the standard time, which can reach us magnitude. The present application thus makes it a prerequisite for the normal use of GNSS receivers comprising at least one satellite in the same orbital plane.
In the present application, as shown in fig. 2, first, any satellite in an orbital plane is selected as a center satellite, and is used as a starting point, and the satellite needs to determine whether the satellite is the center satellite or not, and whether the satellite is the starting point or not. And proceeds to the step of S11 or S12 according to the judgment result.
In fig. 2, the satellite 1 is a central satellite, and the satellites 2, 3, 4, 5, and 6 are all adjacent satellites.
S11: if yes, the time synchronization frame of the central satellite is actively and periodically sent to the adjacent satellite, and a GNSS synchronization method is adopted to synchronize with the GNSS time.
In a specific embodiment, when the central satellite is determined by itself, the time synchronization frame of the central satellite is actively sent to the adjacent satellite of the central satellite periodically, and the adjacent satellite is communicated with the time synchronization frame to perform time synchronization, and a GNSS time synchronization method is adopted to synchronize with the GNSS time, that is, synchronize with standard time such as a ground acquired Beidou satellite, so that the satellite time is synchronized and synchronized with the ground time.
S12: if not, receiving the time synchronization frame from the adjacent satellite, sending the time synchronization frame of the current satellite to the other adjacent satellites, and performing the step of synchronizing with the GNSS time by adopting a GNSS synchronization method.
In a specific embodiment, when the satellite is not a central satellite, the time synchronization frame from the adjacent satellite is received, and after time synchronization with the adjacent satellite, the time synchronization frame is sent to the rest adjacent satellites, and the GNSS time synchronization method is adopted to synchronize with the GNSS time, that is, synchronize with standard time such as a ground-acquired Beidou satellite, so that the satellite time is synchronized and synchronized with the ground time.
As shown in fig. 1, when 1 is the central satellite, the time synchronization frame is sent to the satellite No. 2, after the satellite No. 2 is synchronized with the satellite No. 1 in time, the time synchronization frame of the satellite No. 2 is sent to the satellite No. 3, and the cycle is repeated in sequence, and after the satellite No. 6 is synchronized, the time synchronization frame of the satellite No. 6 needs to be sent to the satellite No. 1, so that the time synchronization between one complete periodic satellite is completed.
The GNSS synchronization method and the GNSS time synchronization need no fault of the GNSS receiver, and when the GNSS receiver in one satellite in one orbit plane has no fault, the GNSS time synchronization method and the GNSS time synchronization method can realize the GNSS time synchronization, namely the standard time synchronization with the ground acquired Beidou satellite and the like. In the whole process of sending and receiving the time synchronization frame, time synchronization is realized among the satellites, only one of the satellites realizes time synchronization with the ground, and the satellites realize time synchronization with the ground.
According to the low-orbit satellite constellation time synchronization method, whether the low-orbit satellite constellation time synchronization method is a central satellite or not needs to be judged, if yes, a time synchronization frame of the central satellite is sent to an adjacent satellite, and a GNSS synchronization method is adopted to synchronize with GNSS time. If not, receiving the time synchronization frame from the adjacent satellite, sending the time synchronization frame of the current satellite to the rest adjacent satellites, and performing the step of adopting a GNSS synchronization method and GNSS time synchronization. The method avoids the defect caused by time synchronization because a single satellite adopts a GNSS receiver and ground communication, and cannot realize time synchronization when the GNSS receiver fails. According to the method, time synchronization between the satellite and the ground can be realized only by at least comprising one GNSS receiver in a plurality of satellites without faults, the satellites are communicated with each other, synchronization between the satellites is realized, the faultless GNSS receiver is adopted again, synchronization with the ground is achieved, and extra requirements on a ground measurement and control station are not required.
In addition to the above embodiments, as a preferred embodiment, if the satellite itself is a central satellite, the method for transmitting the time synchronization frame of the central satellite to the adjacent satellite includes:
judging whether the timing time is reached;
if the timing time is reached, reading the second value and the microsecond value of the central satellite;
the time synchronization frame of the central satellite is filled.
In a specific embodiment, when the GNSS receiver fails, the inter-satellite time synchronization with another satellite is realized through an inter-satellite link, and when the inter-satellite time synchronization is a central satellite, it is necessary to determine whether a timing time is reached, and if the timing time is reached, a second value and a microsecond value of the central satellite are read, and a time synchronization frame of the central satellite is filled. Wherein the format of the time sync frame is as shown in table 1.
TABLE 1
Wherein, the central satellite is the active initiating satellite. The timing time is a cycle time, and after the time synchronization is realized, the time is always synchronized within a certain time, but some devices used in the satellite cannot be completely the same, the loss cannot be calculated, and therefore, the time is different after a certain time, and therefore, a timing time is required for cyclically transmitting and receiving the time synchronization frame.
The timing time is only a preferred mode, and may be one minute, or may be set by the user according to the user's needs, and the present application is not limited.
As shown in fig. 3, the central satellite time synchronization frame transmission processing flow for actively transmitting the time synchronization frame through the inter-satellite link includes the following steps:
s13: and judging whether the timing time is reached.
S14: and reading the second value and the microsecond value of the central satellite.
S15: the time synchronization frame of the central satellite is filled.
S16: and sending the time synchronization frame to the inter-satellite communication machine through the synchronization serial port.
In the method, whether the timing time is reached is judged, and if the timing time is reached, the second value and the microsecond value of the central satellite are read, and the time synchronization frame of the central satellite is filled. And circularly transmitting the time synchronization frame of the central satellite within a certain time, thereby reducing the time error among the satellites.
In addition to the above embodiments, as a preferred embodiment, if the satellite itself is not the central satellite, the method for receiving the time synchronization frame from the adjacent satellite includes:
judging whether the high-precision time of the current satellite is effective or not and whether the high-precision time in the time synchronization frame of the adjacent satellite is effective or not;
if the satellite is valid, reading the second value and the microsecond value of the current satellite;
reading the second value and the microsecond value of the adjacent satellite;
obtaining a calibration value according to the second value and the microsecond value of the adjacent satellite and the second value and the microsecond value of the current satellite;
judging whether the high-precision time or the low-precision time of the current satellite is invalid and whether the sub-precision time of the adjacent satellite is valid;
if the satellite is valid, reading the second value and the microsecond value of the adjacent satellite;
obtaining the satellite time of the current satellite according to the second value, the microsecond value and the calibration value of the adjacent satellite;
setting the sub-precision time of the current satellite to be effective.
In a specific embodiment, after the adjacent satellites receive the time synchronization frame transmitted by the inter-satellite link, the FPGA of the housekeeping computer parses the received inter-satellite data, and after the received inter-satellite data is parsed into a valid frame (the frame header and the frame trailer are correct, and the check is also correct), if the received inter-satellite data is judged to be the time synchronization frame, the on-satellite time (including a second value and a microsecond value) of the current satellite is latched and stored, and the housekeeping processor is notified of the processing through the interruption.
In a particular embodiment, it is determined whether a time synchronization frame is received for an adjacent satellite, where the two satellites are adjacent, where the adjacent satellite may be the center satellite. For example: as shown in fig. 2, six satellites are included in the same orbital plane, and 1, 2, 3, 4, 5, 6, and six satellites form an approximately circular orbit, where 1 is a central satellite, 1 transmits a time synchronization frame of 12,2 and realizes time synchronization with 1, and then transmits a time synchronization frame of 2 to 3, so that the cycle is repeated. From the perspective of 2, the station acquires the time synchronization frame of the central satellite and the adjacent satellite, and from the perspective of 3, the station receives the time synchronization frame of the adjacent satellite.
In a specific embodiment, if the satellite is not the central satellite, receiving a time synchronization frame from the central satellite, determining whether the high-precision time of the current satellite is valid and the high-precision time in the time synchronization frame of the adjacent satellite is valid, if the high-precision time of the current satellite is valid, reading the second value and the microsecond value of the current satellite, reading the second value and the microsecond value of the adjacent satellite (the second value and the microsecond value in the time synchronization frame), obtaining a calibration value according to the second value and the microsecond value of the adjacent satellite and the second value and the microsecond value of the current satellite, determining whether the high-precision time or the low-precision time of the current satellite is invalid and the sub-precision time of the adjacent satellite is valid, if the high-precision time or the low-precision time of the current satellite is valid, reading the second value and the microsecond value of the adjacent satellite, and obtaining the sub-precision time of the current satellite according to the second value, the microsecond value and the calibration value of the adjacent satellite, and setting the sub-precision time of the current satellite to be valid.
In a specific embodiment, a specific calculation manner of the calibration value is obtained according to the second value and the microsecond value of the adjacent satellite and the second value and the microsecond value of the current satellite, which is not limited in the present application, and the second value and the microsecond value of the adjacent satellite may be subtracted from the second value and the microsecond value of the current satellite, or may be set by the user according to the user's needs.
The specific calculation formula of the satellite time of the current satellite is obtained according to the second value, the microsecond value and the calibration value of the adjacent satellite, the calculation formula is not limited in the application, the second value and the microsecond value of the adjacent satellite can be added with the calibration value, and the calculation formula can be set according to the user requirement.
In this embodiment, the time synchronization frames of adjacent satellites are received, and the time synchronization frame of the satellite is adjusted, thereby achieving synchronization between the satellites.
On the basis of the above embodiment, as a preferred embodiment, after setting the sub-accuracy time of the current satellite to be valid, the method further includes:
judging whether the current satellite is the time synchronization frame of the current satellite to actively launch the satellite;
if not, reading the second value and the microsecond value of the current satellite;
and filling the time synchronization frame of the current satellite.
In a specific embodiment, after the sub-precision time of the current satellite is set to be valid, it is further determined whether the current satellite actively initiates a satellite for the time synchronization frame of the current satellite, and if not, the second value and the microsecond value of the current satellite are read and the time synchronization frame of the current satellite is filled. Wherein the time synchronization frame includes a second value and a microsecond value. After the current satellite achieves time synchronization with the adjacent satellite, it needs to fill its time synchronization frame and transmit the next adjacent satellite.
To sum up the above embodiments, as shown in fig. 4, the process of receiving the time synchronization frame includes the following steps:
s17: the time sync frame reception is interrupted.
S18: and judging whether the time synchronization frame sent by the adjacent satellite is received.
S19: and if the time synchronization frame sent by the adjacent satellite is received, judging whether the high-precision time of the satellite is valid and whether the high-precision time in the time synchronization frame is valid. If the time synchronization frame transmitted by the adjacent satellite is not received, the step of S18 is returned to.
S20: and if the time Tr is valid, reading the time Tr latched by the FPGA. If not, the process proceeds to step S23.
S21: the time Ts in the time sync frame is read.
S22: and calculating a calibration value Td, and sending the Td as telemetering.
S23: and judging whether the high/low precision time of the satellite is invalid and whether the secondary low precision time in the time synchronization frame is valid.
S24: if yes, reading time Ts in the time synchronization frame. If not, the process proceeds to step S27.
S25: and calculating the satellite time T.
S26: the local satellite is effectively arranged in low-precision time.
S27: and judging whether the satellite configuration is a time synchronization frame initiative initiating satellite or not.
S28: if not, reading the current satellite hour-second value and microsecond value.
S29: the time synchronization frame is filled.
S30: and sending the time synchronization frame to the inter-satellite communication machine through the synchronization serial port.
Wherein, tr is the second value and microsecond value of the satellite, namely the current satellite, ts is the second value and microsecond value of the adjacent satellite, and Td is the calibration value.
The core of time synchronization through an inter-satellite link is that processing and transmission time delay Td between two adjacent satellites needs to be calibrated, when high-precision time of the two adjacent satellites is effective at the same time, the time delay Td can be measured, and multiple measured values of the Td of multiple satellites are averaged to obtain a calibrated value Td (the deviation from the actual measured value is expected to be less than 0.5 ms). After the transmission delay is obtained, the current time of the satellite can be obtained by adding the standard time delay to the time in the received time synchronization frame, so that the time synchronization with other satellites is realized.
On the basis of the above embodiments, as a preferred embodiment, the GNSS synchronization method and GNSS time synchronization are adopted, and the method includes:
judging whether a GNSS receiver sends a PPS rising edge or not;
if the fact that the GNSS receiver sends the PPS rising edge is detected, delaying the first time, receiving and analyzing a GNSS telemetering packet;
judging whether the GNSS telemetry packet passes verification and whether the GNSS receiver is effective in positioning;
if the GNSS telemetry packet is not checked or the GNSS receiver is invalid in positioning, adding 1 to the GNSS continuous positioning invalid count, and clearing the GNSS continuous positioning valid count;
if the GNSS telemetry packet passes the verification and the GNSS receiver is effectively positioned, judging whether the difference value before and after the time in the GNSS telemetry packet is equal to a second time or not;
if the difference value before and after the time in the GNSS telemetering packet is not equal to the second time, adding 1 to the GNSS continuous positioning invalid count, and clearing the GNSS continuous positioning valid count;
if the difference value between the time in the GNSS telemetry packet and the time before and after the time in the GNSS telemetry packet is equal to the second time, judging whether the current satellite time is synchronous with the GNSS time and whether the difference value between the current satellite time and the GNSS time is larger than a third time;
if the current satellite time and the GNSS time are synchronous and the difference value of the current satellite time and the GNSS time is more than the third time, setting the high-precision time of the current satellite to be invalid and setting the low-precision time of the current satellite to be invalid;
and if the current satellite time is not synchronous with the GNSS time or the difference value between the current satellite time and the GNSS time is not more than the third time, adding 1 to the GNSS continuous positioning valid count, and clearing the GNSS continuous positioning invalid times.
In a specific embodiment, a GNSS synchronization method is adopted to synchronize with GNSS time, namely, time synchronization with the ground is realized, a GNSS receiver sends out a PPS signal every second, therefore, whether a PPS rising edge sent by the GNSS receiver is detected or not is judged firstly, if the PPS rising edge sent by the GNSS receiver is detected, a GNSS telemetering packet is received and analyzed after the first time is delayed, and whether the GNSS telemetering packet is checked to pass or not and whether the positioning of the GNSS receiver is valid or not is judged, wherein the GNSS telemetering packet comprises positioning state, time, track position and speed information and is required to be valid or not, and if the GNSS telemetering packet is not checked to pass or the positioning of the GNSS receiver is invalid, the GNSS continuous positioning invalid count is added with 1, and the GNSS continuous positioning valid count is cleared; the number of consecutive invalidations is counted. And if the GNSS telemetry packet passes the verification and the GNSS receiver is effectively positioned, judging whether the difference value between the time before and after in the GNSS telemetry packet is equal to the second time or not, and carrying out primary verification on the judgment to prove that the GNSS receiver sending the PPS signal is intact. And if the difference value before and after the time in the GNSS telemetering packet is not equal to the second time, adding 1 to the GNSS continuous positioning invalid count, and clearing the GNSS continuous positioning valid count, which is also the invalid counting times. If the difference value between the time before and after the GNSS telemetering packet is equal to the second time, whether the current satellite time is synchronous with the GNSS time or not and whether the difference value between the current satellite time and the GNSS time is larger than the third time or not are continuously judged, and the judgment is also a protection measure to carry out verification. And if the current satellite time and the GNSS time are synchronous and the difference value of the current satellite time and the GNSS time is greater than the third time, setting the high-precision time of the current satellite to be invalid and setting the low-precision time of the current satellite to be invalid. And if the current satellite time is not synchronous with the GNSS time or the difference value between the current satellite time and the GNSS time is not more than the third time, adding 1 to the GNSS continuous positioning valid count, clearing the GNSS continuous positioning invalid times and calculating the valid times.
As a preferred embodiment, the first time may be 50ms, the second time may be 1s, and the third time may be 20s. However, this embodiment is only a preferred method, and can be set by the user according to the user's needs.
On the basis of the above embodiment, as a preferred embodiment, after adding 1 to the GNSS positioning invalid count and clearing the GNSS positioning valid count, the method further includes:
judging whether the times of the GNSS continuous positioning invalidity are greater than a first time;
if the number of times is larger than the first number of times, setting the low-precision time of the current satellite to be invalid;
if the number of times of the GNSS continuous positioning invalidation is not more than the first time, judging whether the number of times of the GNSS continuous positioning invalidation is more than a second number of times;
and if the number of times is larger than the second number of times, setting the high-precision time of the current satellite to be invalid.
In a specific embodiment, the PPS signal is transmitted in whole seconds, that is, every second, when the number of times of GNSS continuous positioning invalidation is greater than a first number, the low-precision time of the current satellite is set to be invalid, when the number of times of GNSS continuous positioning invalidation is not greater than the first number, it is required to determine whether the number of times is greater than a second number, and when the number of times is greater than the second number, the high-precision time is invalid. That is, the information in the time synchronization frame of the current satellite contains the satellite GNSS receiver which has a fault, and the synchronization with the ground cannot be realized.
The first number may be 1800 and the second number may be 5 as a preferred embodiment, but the present invention is also limited to a preferred embodiment, and the first number and the second number may be selected by the user according to the user's needs.
On the basis of the foregoing embodiment, as a preferred embodiment, after adding 1 to the GNSS continuous positioning valid count and clearing the number of times of GNSS continuous positioning invalidity, the method further includes:
judging whether the effective times of the GNSS continuous positioning are greater than a second time or not;
if the GNSS continuous positioning effective times are larger than the second time, judging whether the absolute value of the time difference between the satellite affair and the GNSS is larger than the fourth time;
if the time is more than the fourth time, setting the current satellite time as a time second value in the GNSS telemetry packet;
if the time is not more than the fourth time, judging whether the microsecond value of the current satellite at the PPS moment is more than the fifth time or not;
if the time is not more than the fifth time, adjusting the satellite time according to the first calculation mode;
if the time is longer than the fifth time, adjusting the satellite time according to a second calculation mode;
setting the high-precision time of the current satellite to be effective;
it is effective to set the low-precision time of the current satellite.
In the specific embodiment, after the continuous positioning is effective, whether the effective time of the GNSS continuous positioning is more than a second time or not is judged, if so, whether the absolute value of the time difference between the satellite service and the GNSS is more than a fourth time or not is continuously judged, if so, the second value of the GNSS telemetry packet is determined as the second value of the time in the GNSS telemetry packet when the satellite is currently on the satellite,
if the time is not more than the fourth time, continuously judging whether the microsecond value of the current satellite at the PPS time is more than the fifth time, if the time is not more than the fifth time, adjusting the satellite according to the first calculation mode, if the time is more than the fifth time, adjusting the satellite according to the second calculation mode, wherein the satellite of the current satellite is adjusted, but the calculation formulas may be the same or different. And it is effective to set the high-precision and low-precision times of the current satellite.
Wherein, as a preferred embodiment, the second number may be 5, the fourth time is 400ms, and the fifth time is 500000us. The method and the device do not limit specific numerical values and can be set automatically according to the requirements of users.
The first calculation formula and the second calculation formula are not limited in the application and can be set by users according to the needs of the users.
By integrating the above embodiments, each satellite can obtain its own high/low precision time valid flag, that is, if the GNSS receiver is continuously located valid, the high/low precision time is valid, and the satellite service time is automatically synchronized with the GNSS time. The PPS signal is transmitted for a whole second. If the subsequent GNSS receiver continuously exceeds 5s for non-positioning, the high-precision time is invalid, and if the subsequent GNSS receiver continuously exceeds 30 minutes for positioning, the low-precision time is invalid. If the continuous positioning is invalid for less than 30 minutes, self-timekeeping is carried out by depending on the high-stability crystal oscillator of the star computer, and the drift can be controlled within 0.5ms within 30 minutes when the star computer is on the satellite.
In summary of the above embodiments, as shown in fig. 5: the GNSS synchronization method and the GNSS time synchronization method comprise the following steps:
s31: and starting.
S32: and judging whether the PPS rising edge sent by the GNSS is detected.
S33: if yes, receiving the GNSS telemetry packet after delaying for 50ms and analyzing. If not, the process returns to step S32.
S34: and judging whether the GNSS telemetry packet is verified to pass the & GNSS and whether the positioning is valid.
S35: if the count is invalid, the GNSS continuously invalid count is +1, and the GNSS continuously valid count is cleared.
S36: if the time difference is 1s, judging whether the time difference between the time of the GNSS telemetry packet and the time of the GNSS telemetry packet is 1s. If not, the process proceeds to step S35.
S37: if yes, judging whether the on-satellite time and the GNSS are synchronized and whether the time difference between the on-satellite time and the GNSS is greater than 20s.
S38: if yes, setting high-precision time invalid.
S39: setting a low precision time is not effective.
S40: if not, the GNSS continuous effective count is +1, and the GNSS continuous ineffective count is cleared.
S41: it is determined whether the GNSS consecutive valid count is >5.
S42: if yes, judging that the absolute value of the time difference between the satellite affair and the GNSS exceeds 400ms.
S43: if yes, the satellite time is set as a time second value in the GNSS telemetry packet.
S44: if not, judging that the satellite microsecond value us _ val at the PPS moment is greater than 500000.
S45: if not, the us _ val microsecond is subtracted when the satellite is adjusted.
S46: if yes, then adjust the satellite, add 100000-us _ val microseconds.
S47: it is effective to set high-precision time.
S48: it is effective to set the low-precision time.
S49: the on-board time and GNSS time synchronized flag is set.
S50: after step S35, it is determined whether the GNSS continuous invalid count is >1800.
S51: if so, setting the low-precision time is invalid.
S52: if not, judging whether the GNSS continuous invalid count is larger than 5.
S53: if yes, setting high-precision time invalid.
In the above embodiments, the low-earth orbit satellite constellation time method is described in detail, and the present application also provides embodiments corresponding to the low-earth orbit satellite constellation time apparatus. It should be noted that the present application describes the embodiments of the apparatus portion from two perspectives, one from the perspective of the function module and the other from the perspective of the hardware.
As shown in fig. 6, a low earth orbit satellite constellation time synchronization system comprises:
the judging module 11 is used for judging whether the satellite is a central satellite;
a sending module 12, configured to actively and periodically send a time synchronization frame of a central satellite to an adjacent satellite when the sending module is the central satellite, and adopt a GNSS synchronization method to synchronize with GNSS time;
the receiving module 13 is configured to receive the time synchronization frame from the adjacent satellite, and when the receiving module is not the central satellite, send the time synchronization frame of the current satellite to the other adjacent satellites, and perform a step of performing GNSS synchronization with the GNSS time by using a GNSS synchronization method.
Since the embodiments of the apparatus portion and the method portion correspond to each other, please refer to the description of the embodiments of the method portion for the embodiments of the apparatus portion, which is not repeated here.
Fig. 7 is a structural diagram of a low earth orbit satellite constellation time synchronization apparatus according to another embodiment of the present application, and as shown in fig. 7, the low earth orbit satellite constellation time synchronization apparatus includes: a memory 20 for storing a computer program;
a processor 21 adapted to carry out the steps of the method of time synchronization of low earth orbit satellite constellations as mentioned in the above embodiments when executing the computer program.
The processor 21 may include one or more processing cores, such as a 4-core processor, an 8-core processor, and the like. The Processor 21 may be implemented in hardware using at least one of a Digital Signal Processor (DSP), a Field-Programmable Gate Array (FPGA), and a Programmable Logic Array (PLA). The processor 21 may also include a main processor and a coprocessor, where the main processor is a processor for Processing data in a wake state, and is also called a Central Processing Unit (CPU); a coprocessor is a low power processor for processing data in a standby state. In some embodiments, the processor 21 may be integrated with a Graphics Processing Unit (GPU) which is responsible for rendering and drawing the content required to be displayed by the display screen. In some embodiments, the processor 21 may further include an Artificial Intelligence (AI) processor for processing computational operations related to machine learning.
The memory 20 may include one or more computer-readable storage media, which may be non-transitory. Memory 20 may also include high speed random access memory, as well as non-volatile memory, such as one or more magnetic disk storage devices, flash memory storage devices. In this embodiment, the memory 20 is at least used for storing the following computer program 201, wherein the computer program is loaded and executed by the processor 21, and is capable of implementing relevant steps of a low earth orbit satellite constellation time synchronization method disclosed in any of the foregoing embodiments. In addition, the resources stored in the memory 20 may also include an operating system 202, data 203, and the like, and the storage manner may be a transient storage manner or a permanent storage manner. Operating system 202 may include, among other things, windows, unix, linux, etc.
In some embodiments, the low earth orbit satellite constellation time synchronization device may further include a display screen 22, an input/output interface 23, a communication interface 24, a power supply 25, and a communication bus 26.
Those skilled in the art will appreciate that the configuration shown in fig. 7 does not constitute a limitation of the low earth orbit satellite constellation time synchronizer and may include more or fewer components than those shown.
The low earth orbit satellite constellation time synchronization device provided by the embodiment of the application comprises a memory and a processor, wherein when the processor executes a program stored in the memory, the following method can be realized: a low earth orbit satellite constellation time synchronization method.
Finally, the application also provides a corresponding embodiment of the computer readable storage medium. The computer-readable storage medium has stored thereon a computer program which, when being executed by a processor, carries out the steps as set forth in the above-mentioned method embodiments.
It is to be understood that if the method in the above embodiments is implemented in the form of software functional units and sold or used as a stand-alone product, it can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application may be embodied in the form of a software product, which is stored in a storage medium and executes all or part of the steps of the methods described in the embodiments of the present application, or all or part of the technical solutions. And the aforementioned storage medium includes: various media capable of storing 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.
A method, a system, a device and a medium for low earth orbit satellite constellation time synchronization provided by the present application are introduced in detail above. The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed in the embodiment corresponds to the method disclosed in the embodiment, so that the description is simple, and the relevant points can be referred to the description of the method part. It should be noted that, for those skilled in the art, without departing from the principle of the present application, the present application can also make several improvements and modifications, and those improvements and modifications also fall into the protection scope of the claims of the present application.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
Claims (9)
1. A method for time synchronization of low earth orbit satellite constellations, the method comprising:
judging whether the satellite is a central satellite;
if so, actively and periodically sending the time synchronization frame of the central satellite to an adjacent satellite, and synchronizing with the GNSS time by adopting a GNSS synchronization method;
if not, receiving the time synchronization frame from the adjacent satellite, sending the time synchronization frame of the current satellite to the rest adjacent satellites, and performing the step of synchronizing with the GNSS time by adopting a GNSS synchronization method;
the method for synchronizing the GNSS and the GNSS time comprises the following steps:
judging whether a GNSS receiver sends a PPS rising edge or not;
if the GNSS receiver is detected to send out a PPS rising edge, delaying the first time, receiving a GNSS telemetering packet and analyzing;
judging whether the GNSS telemetry packet passes verification and whether the GNSS receiver is effective in positioning;
if the GNSS telemetry packet is not verified or the GNSS receiver is invalid for positioning, adding 1 to the GNSS continuous positioning invalid count, and clearing the GNSS continuous positioning valid count;
if the GNSS telemetry packet passes verification and the GNSS receiver is positioned effectively, judging whether a difference value between the time before and after in the GNSS telemetry packet is equal to a second time;
if the difference value before and after the time in the GNSS telemetering packet is not equal to the second time, adding 1 to the GNSS continuous positioning invalid count, and clearing the GNSS continuous positioning valid count;
if the difference value between the time in the GNSS telemetry packet and the time before and after the time in the GNSS telemetry packet is equal to a second time, judging whether the current satellite time is synchronous with the GNSS time and whether the difference value between the current satellite time and the GNSS time is larger than a third time;
if the current satellite time is synchronous with the GNSS time and the difference value between the current satellite time and the GNSS time is greater than a third time, setting the high-precision time of the current satellite to be invalid and setting the low-precision time of the current satellite to be invalid;
and if the time of the current satellite is not synchronous with the GNSS time or the difference value between the time of the current satellite and the GNSS time is not more than a third time, adding 1 to the GNSS continuous positioning valid count, and clearing the GNSS continuous positioning invalid times.
2. The method according to claim 1, wherein if the self is a central satellite, sending the time synchronization frame of the central satellite to an adjacent satellite comprises:
judging whether the timing time is reached;
if the timing time is reached, reading a second value and a microsecond value of the central satellite;
the time synchronization frame of the central satellite is filled.
3. The method of claim 2, wherein receiving the time synchronization frame from the neighboring satellite if the satellite is not the central satellite comprises:
judging whether the high-precision time of the current satellite is effective or not and whether the high-precision time in the time synchronization frame of the adjacent satellite is effective or not;
if the satellite is valid, reading the second value and the microsecond value of the current satellite;
reading the second value and the microsecond value of the adjacent satellite;
obtaining a calibration value according to the second value and the microsecond value of the adjacent satellite and the second value and the microsecond value of the current satellite;
judging whether the current satellite meets the conditions that the high or low precision time of the current satellite is invalid and the sub-precision time of the adjacent satellite is valid;
if yes, reading the second value and the microsecond value of the adjacent satellite;
obtaining the satellite time of the current satellite according to the second value, the microsecond value and the calibration value of the adjacent satellite;
and setting the sub-precision time of the current satellite to be effective.
4. The method for time synchronization of low earth orbit satellite constellations of claim 3, wherein after the setting the sub-precision time of the current satellite is valid, further comprising:
judging whether the current satellite is the time synchronization frame of the current satellite to actively launch the satellite;
if not, reading the second value and the microsecond value of the current satellite;
and filling the time synchronization frame of the current satellite.
5. The method for time synchronization of low earth orbit satellite constellations of any one of claims 1-4, wherein after incrementing the GNSS location invalid count by 1 and clearing the GNSS location valid count, further comprising:
judging whether the number of times of the GNSS continuous positioning invalidity is greater than a first number of times;
if the current satellite is greater than the first time, setting the low-precision time of the current satellite to be invalid;
if the number of times of the GNSS continuous positioning invalidation is not more than the first time, judging whether the number of times of the GNSS continuous positioning invalidation is more than a second number of times;
and if the time is greater than the second time, setting the high-precision time of the current satellite to be invalid.
6. The method of claim 5, wherein after the GNSS consecutive position fix valid count is incremented by 1 and the GNSS consecutive position fix invalid times is cleared, the method further comprises:
judging whether the GNSS continuous positioning effective times are greater than the second times or not;
if the GNSS continuous positioning effective times are greater than the second times, judging whether the absolute value of the time difference between the satellite affairs and the GNSS is greater than fourth time;
if the current satellite time is greater than the fourth time, setting the current satellite time as a time second value in the GNSS telemetry packet;
if the time is not more than the fourth time, judging whether the microsecond value of the current satellite at the PPS moment is more than a fifth time or not;
if the time is not more than the fifth time, adjusting the satellite time according to a first calculation mode;
if the time is longer than the fifth time, adjusting the satellite time according to a second calculation mode;
setting the high-precision time of the current satellite to be effective;
and setting the low-precision time of the current satellite to be effective.
7. A low earth orbit satellite constellation time synchronization system, comprising:
the judging module is used for judging whether the satellite is a central satellite;
the transmitting module is used for actively and periodically transmitting the time synchronization frame of the central satellite to an adjacent satellite when the central satellite is the central satellite, and is synchronized with the GNSS time by adopting a GNSS synchronization method;
a receiving module, configured to receive the time synchronization frame from the adjacent satellite, and when the receiving module is not the central satellite, send the time synchronization frame of the current satellite to the remaining adjacent satellites, and perform GNSS time synchronization with the current satellite by using a GNSS synchronization method;
the method for synchronizing the GNSS and the GNSS time comprises the following steps:
judging whether a GNSS receiver sends a PPS rising edge or not;
if the GNSS receiver is detected to send out a PPS rising edge, delaying the first time, receiving a GNSS telemetering packet and analyzing;
judging whether the GNSS telemetry packet passes verification and whether the GNSS receiver is effective in positioning;
if the GNSS telemetry packet is not checked or the GNSS receiver is invalid in positioning, adding 1 to the GNSS continuous positioning invalid count, and clearing the GNSS continuous positioning valid count;
if the GNSS telemetry packet passes the verification and the GNSS receiver is effectively positioned, judging whether a difference value before and after time in the GNSS telemetry packet is equal to second time or not;
if the difference value before and after the time in the GNSS telemetering packet is not equal to the second time, adding 1 to the GNSS continuous positioning invalid count, and clearing the GNSS continuous positioning valid count;
if the difference value between the time in the GNSS telemetry packet and the time before and after the time in the GNSS telemetry packet is equal to a second time, judging whether the current satellite time is synchronous with the GNSS time and whether the difference value between the current satellite time and the GNSS time is larger than a third time;
if the current satellite time is synchronous with the GNSS time and the difference value between the current satellite time and the GNSS time is greater than a third time, setting the high-precision time of the current satellite to be invalid and setting the low-precision time of the current satellite to be invalid;
and if the time of the current satellite is not synchronous with the GNSS time or the difference value between the time of the current satellite and the GNSS time is not more than a third time, adding 1 to the GNSS continuous positioning valid count, and clearing the GNSS continuous positioning invalid times.
8. A low earth orbit satellite constellation time synchronization apparatus, comprising a memory for storing a computer program;
a processor for implementing the steps of the low earth satellite constellation time synchronization method according to any of claims 1 to 6 when executing said computer program.
9. A computer readable storage medium, having stored thereon a computer program which, when being executed by a processor, carries out the steps of the method for time synchronization of low earth orbit satellite constellations of any one of claims 1 to 6.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211637730.3A CN115623582B (en) | 2022-12-20 | 2022-12-20 | Low-orbit satellite constellation time synchronization method, system, device and medium |
| PCT/CN2023/125868 WO2024131257A1 (en) | 2022-12-20 | 2023-10-23 | Low-earth-orbit satellite constellation time synchronization method, system and apparatus, and medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211637730.3A CN115623582B (en) | 2022-12-20 | 2022-12-20 | Low-orbit satellite constellation time synchronization method, system, device and medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115623582A CN115623582A (en) | 2023-01-17 |
| CN115623582B true CN115623582B (en) | 2023-03-28 |
Family
ID=84880239
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211637730.3A Active CN115623582B (en) | 2022-12-20 | 2022-12-20 | Low-orbit satellite constellation time synchronization method, system, device and medium |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN115623582B (en) |
| WO (1) | WO2024131257A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115623582B (en) * | 2022-12-20 | 2023-03-28 | 浙江吉利控股集团有限公司 | Low-orbit satellite constellation time synchronization method, system, device and medium |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015021899A (en) * | 2013-07-22 | 2015-02-02 | 日本無線株式会社 | Satellite clock accuracy judging device, method and positioning device |
| CN114157338A (en) * | 2021-11-08 | 2022-03-08 | 浙江时空道宇科技有限公司 | Satellite network communication method and system |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0552928A (en) * | 1991-08-29 | 1993-03-02 | Mitsubishi Electric Corp | Position measuring method using satellite |
| US8441398B2 (en) * | 2010-02-03 | 2013-05-14 | Texas Instruments Incorporated | Receivers, circuits, and methods to improve GNSS time-to-fix and other performances |
| CN102291169B (en) * | 2011-09-09 | 2014-04-02 | 航天东方红卫星有限公司 | Onboard high-accuracy time synchronization method for satellite |
| WO2017024541A1 (en) * | 2015-08-12 | 2017-02-16 | 华为技术有限公司 | Synchronous communication method and terminal |
| KR101651647B1 (en) * | 2015-09-09 | 2016-08-26 | 한국항공우주연구원 | Time synchronization method between satellite and ground equipment, and satellite system thereof |
| EP3355079B8 (en) * | 2017-01-25 | 2023-06-21 | Airbus Defence and Space GmbH | Method for each of a plurality of satellites of a secondary global navigation satellite system in a low earth orbit |
| CN110518960B (en) * | 2019-08-13 | 2021-07-13 | 西安空间无线电技术研究所 | A highly robust satellite constellation time self-synchronization method |
| CN112904705B (en) * | 2021-01-22 | 2022-05-17 | 重庆邮电大学 | A Hierarchical Clock Synchronization Method Between Low-Orbit Small Satellites |
| CN115361086B (en) * | 2022-10-18 | 2023-01-31 | 浙江时空道宇科技有限公司 | Time synchronization method, device and medium for inter-satellite link |
| CN115623582B (en) * | 2022-12-20 | 2023-03-28 | 浙江吉利控股集团有限公司 | Low-orbit satellite constellation time synchronization method, system, device and medium |
-
2022
- 2022-12-20 CN CN202211637730.3A patent/CN115623582B/en active Active
-
2023
- 2023-10-23 WO PCT/CN2023/125868 patent/WO2024131257A1/en unknown
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015021899A (en) * | 2013-07-22 | 2015-02-02 | 日本無線株式会社 | Satellite clock accuracy judging device, method and positioning device |
| CN114157338A (en) * | 2021-11-08 | 2022-03-08 | 浙江时空道宇科技有限公司 | Satellite network communication method and system |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2024131257A1 (en) | 2024-06-27 |
| CN115623582A (en) | 2023-01-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102098194B (en) | Method and system for realizing time synchronization in local area network | |
| US12099126B2 (en) | Navigation satellite time system and its autonomous recovery method | |
| US7864817B2 (en) | Transport systems and methods incorporating absolute time references and selective buildout delays | |
| EP3846379A1 (en) | Clock synchronization method and apparatus, system, storage medium, and electronic device | |
| CN103563287A (en) | Synchronization device and synchronization method | |
| CN115623582B (en) | Low-orbit satellite constellation time synchronization method, system, device and medium | |
| CN102023565B (en) | Device and method for outputting time information | |
| CN106899371A (en) | Method for synchronizing time and device | |
| CA2883106A1 (en) | Method for providing synchronization in a data acquisition system | |
| Chowdhury | NextGen Network Synchronization | |
| CN115361086B (en) | Time synchronization method, device and medium for inter-satellite link | |
| JPH11154920A (en) | Clock synchronizing method for synchronizing-type base station control system and its synchronizing device | |
| US11493636B2 (en) | Master/slave ensembling for satellite-system timekeeping | |
| GB2300789A (en) | Transmission time measurement in data networks | |
| EP2493094A1 (en) | Method and system for synchronizing time and frequency sources, particularly for video data transmissions | |
| CN107528655A (en) | Method for synchronizing time and clock synchronization system | |
| US11300688B2 (en) | Phase clock performance improvement for a system embedded with GNSS receiver | |
| US7499512B2 (en) | Clock transmission apparatus for network synchronization between systems using an even-second clock and an Unshielded Twisted Pair (UTP) | |
| CN112748758A (en) | Clock source selection method and device, electronic equipment and storage medium | |
| CN118921732A (en) | Method and system for realizing time synchronization of networking satellites | |
| CN115347969B (en) | A time synchronization method, device and medium for low-orbit satellite | |
| CN107643529B (en) | Independent time support method for high-orbit remote sensing satellite | |
| KR102042423B1 (en) | GPS Synchronization Method of Low Earth Orbit Satellite Time | |
| CN113141227A (en) | Time determination method, system and medium based on hierarchical control | |
| KR20040106981A (en) | 1PPS generator using GPS |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |