CN114422065A - A high-orbit remote sensing satellite on-board time synchronization system and method - Google Patents

Abstract

The invention relates to a high-orbit remote sensing satellite on-board time synchronization system and method, and belongs to the technical field of on-board time systems for high-orbit satellites. The present invention proposes for the first time that the high-orbit GNSS navigation receiving system is used for satellite-ground time synchronization in high-orbit, which solves the problems that high-orbit satellites can only rely on ground measurement and control for time correction, and the time correction accuracy is not high and the operation cost is high. At the same time, the immediacy of the time error obtained by the navigation receiving system is used to calibrate the long-term drift of the high-stability clock source and the high-stability clock, which solves the problem of long-term index drift of the high-stability clock source and the high-stability clock, and ensures the accuracy of the onboard clock system. . Then, a highly stable clock source is used to keep the precise time of the satellite, which solves the problem of low reliability of receiving GNSS navigation signals in high orbit.

Description

A high-orbit remote sensing satellite on-board time synchronization system and method

technical field

The invention relates to a high-orbit remote sensing satellite on-board time synchronization system and method, and belongs to the technical field of on-board time systems for high-orbit satellites.

Background technique

Geosynchronous orbit satellites generally use ground time service, on-board high-stability clocks are punctual, and at the same time provide the platform's precise time scale solution, which requires frequent time synchronization through the ground measurement and control station system, and complex satellite-ground time alignment and correction measures to ensure . The satellite-ground time synchronization accuracy can be guaranteed to be 1-10ms per day. If a higher-precision satellite-ground time synchronization accuracy needs to be ensured, the ground measurement and control station needs to perform time calibration once a day or even several hours apart. With the development and application of high-orbit remote sensing satellites, the requirements for satellite time accuracy of payloads gradually increase, and at the same time, users' demands for satellite autonomy also gradually increase. High-precision, autonomous time synchronization development requirements.

SUMMARY OF THE INVENTION

The technical solution of the present invention is to overcome the deficiencies of the prior art, and propose a high-orbit remote sensing satellite on-board time synchronization system and method, which is a space-based autonomous high-precision time synchronization system and method, Without relying on the calibration operation of the ground measurement and control station, it can autonomously achieve microsecond or even nanosecond-level satellite-to-ground time synchronization in orbit, reducing the dependence of satellites on the ground, which can effectively improve the flexibility of satellite applications and the ability to operate autonomously.

The technical solution of the present invention is:

An on-board time synchronization system for a high-orbit remote sensing satellite, the on-board time synchronization system includes a high-orbit GNSS navigation receiving system, a highly stable clock source, a data management system and a bus terminal;

The bus terminal is divided into a high-precision application demand bus terminal and a conventional precision application demand bus terminal; the time precision of the high-precision application demand bus terminal is on the order of μs; the conventional precision application demand bus terminal The time precision of the bus terminal is the amount of ms class;

The described high-orbit GNSS navigation receiving system is used to receive the navigation information of the navigation satellite constellation, and obtains the time information of the standard time according to the received navigation information as the benchmark of the satellite-earth time system calibration;

The high-orbit GNSS navigation receiving system converts the time information of the acquired standard time into the hardware second pulse information and the whole second time code corresponding to the hardware second pulse information;

The high-orbit GNSS navigation receiving system transmits the converted hardware second pulse information to a highly stable clock source through a signal line;

The high-orbit GNSS navigation receiving system transmits the whole-second time code corresponding to the converted hardware second pulse information to a highly stable clock source through the bus;

The highly stable clock source is used to receive the hardware second pulse information and the whole second time code transmitted by the high-orbit GNSS navigation receiving system, and use the received hardware second pulse information and the whole second time code to calibrate the internal clock to generate a clock that can be used as a clock. the time base used on the star;

The highly stable clock source converts the generated time reference used on the satellite into hardware second pulse information and whole second time code. The hardware second pulse information is transmitted to the high-precision application demand bus terminal through the signal line, and the whole second time code passes through The bus is passed to the bus terminal of high-precision application requirements, providing a time reference for the bus terminal of high-precision application requirements;

The data management system sends the current time of the data management system to the highly stable clock source through the bus, and the highly stable clock source calibrates the current time of the data management system by using the generated time reference used on the satellite, produces the time difference of the time calibration, and generates a The time difference is transmitted to the data management system through the bus, and the data management system completes the time calibration according to the received time difference, and sends the calibrated time to the bus terminal required by conventional precision applications to provide time for the bus terminal required by conventional precision applications. benchmark.

Preferably, the high-precision application requires the time precision of the bus terminal to be 1-40 μs, and the conventional precision application requires the time precision of the bus terminal to be 1-10 ms.

Preferably, the high-stability clock source also corrects the long-term clock drift of the high-stability clock according to the received hardware second pulse information of the high-orbit GNSS navigation receiving system.

Preferably, the bus terminal required by the conventional precision application is used to maintain the conventional operation of the satellite, and receives the conventional precision time reference broadcast by the data management system through the bus, as the time reference of these bus terminals, including the thermal control subsystem, Measurement and control subsystem, data transmission subsystem, etc.

Preferably, the bus terminal required for high-precision applications participates in payload imaging applications and ensures imaging quality, including payload subsystems, control subsystems, and other subsystems that require high time accuracy.

Preferably, the method for the high-orbit GNSS navigation receiving system to obtain the time information of the standard time according to the received navigation information is as follows: by configuring the high-orbit GNSS navigation system to receive the GNSS navigation signals transmitted across the earth, and to calculate and navigate between satellites information such as the distance and navigation message of the satellite to obtain the time information of the current moment of the satellite.

A method for on-board time synchronization of a high-orbit remote sensing satellite, the steps of the method include:

In the first step, the high-orbit GNSS navigation receiving system receives the navigation information of the navigation satellite constellation, and obtains the time information of the standard time according to the received navigation information, which is used as the benchmark for the satellite-earth time system calibration;

In the second step, the high-orbit GNSS navigation receiving system converts the obtained time information of standard time into hardware second pulse information and the whole-second time code corresponding to the hardware second pulse information, and transmits the converted hardware second pulse information to the high-speed pulse through the signal line. Stable clock source, the high-orbit GNSS navigation receiving system transmits the whole second time code corresponding to the converted hardware second pulse information to the highly stable clock source through the bus;

In the third step, the highly stable clock source receives the hardware second pulse information and the whole second time code transmitted by the high-orbit GNSS navigation receiving system, and calibrates the internal clock of the highly stable clock source according to the received hardware second pulse information and the whole second time code. , generate a time reference that can be used on the satellite, and maintain the generated time reference used on the satellite; the highly stable clock source also uses its highly stable clock to provide a highly stable clock for the high-orbit GNSS navigation receiving system Signal;

In the fourth step, the high-stability clock source converts the generated time reference used on the satellite into the hardware second pulse information and the whole second time code corresponding to the hardware second pulse information, and provides it to the bus terminal for high-precision applications that require high time accuracy. use;

In the fifth step, the highly stable clock source performs time calibration with the data management system through the bus, and the data management system obtains the calibrated time information through the calibration of the highly stable clock source, and maintains the time reference of conventional precision inside the data management system;

In the sixth step, the data management system distributes the time information calibrated by the high-stable clock source to the bus terminal for use by conventional precision applications through broadcasting;

In the seventh step, the highly stable clock source maintains the generated time reference used on the satellite on time;

The eighth step, the high-stability clock source uses the hardware second pulse information of the high-orbit GNSS navigation receiving system to correct the long-term clock drift of the high-stability clock;

The ninth step, the high-stability clock source provides the high-stability clock signal to the system on the satellite that needs to use the high-stability clock.

Compared with the prior art, the present invention has the following beneficial effects:

(1) For the first time, the present invention proposes to use the GNSS navigation system for satellite-ground time synchronization in high orbit, which solves the problems that high-orbit satellites can only rely on ground measurement and control for time correction, and the time correction accuracy is not high and the operating cost is high. At the same time, the long-term drift of the high-stability clock of the high-stability clock source is calibrated by adopting the immediacy of the time error of the navigation receiving system, which solves the problem of long-term index drift of the high-stability clock and ensures the accuracy of the onboard clock system. The use of a highly stable clock to keep track of the precise time of the satellite solves the problem of low reliability of GNSS navigation signals received in high orbits.

(2) Compared with ordinary high-orbit remote sensing satellites, a high-orbit GNSS navigation receiving system is added, which can be used for on-board autonomous time correction. Compared with previous remote sensing satellites, the core equipment of punctuality and timing is transferred from the navigation receiving system to a highly stable clock source, which improves the accuracy and reliability of the system. The traceability and calibration of the precision of the highly stable clock signal by using the second pulse of the navigation receiving system is added, which solves the problem of time offset errors after long-term operation in the process of autonomous punctuality and timing.

(3) The on-board time synchronization system and method of the present invention is a design and scheme with extremely low dependence on ground time correction, and low constraints on weak signals and low reliability of the high-orbit GNSS navigation receiving system. It saves the time, personnel and economic cost of ground operation control management. It is highly reliable, high-precision, and can operate independently, safely and stably. It meets the requirements of high-orbit remote sensing satellites for satellite-ground time synchronization accuracy and on-board time maintenance accuracy. It has a very good application. value.

(4) The present invention aims at the independent requirements and characteristics of high-orbit remote sensing satellites for satellite-to-ground time synchronization accuracy and on-board time calibration, so that the satellite can independently complete the satellite-to-ground time calibration and maintain the accuracy of microseconds or even nanoseconds during the on-orbit operation of the satellite. , which can be completely separated from the ground measurement and control school and work independently and stably for a long time. The time synchronization system can effectively reduce the cost of ground measurement and control operation and control while meeting the time accuracy and autonomy requirements of high-orbit remote sensing satellites, and improve the ease of use and ease of use of the satellites.

(5) The high-stability clock source of the present invention provides the high-stability clock signal to the system on the satellite that needs to use the high-stability clock, ensures the stability of the clock application and the consistency of the clock phase, and improves the synchronization accuracy.

Description of drawings

FIG. 1 is a schematic diagram of the composition of a high-orbit remote sensing satellite on-board time synchronization system of the present invention.

Detailed ways

To make the purposes, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention.

An on-board time synchronization system for a high-orbit remote sensing satellite, the on-board time synchronization system includes a high-orbit GNSS navigation receiving system, a highly stable clock source, a data management system and a bus terminal;

The bus terminals are divided into high-precision application requirements bus terminals and conventional precision application requirements bus terminals; the high-precision application requirements bus terminal time accuracy of the order of μs, preferably 1 ~ 40μs, conventional precision applications require the time accuracy of the bus terminal is on the order of ms, preferably 1 to 10 ms;

The described high-orbit GNSS navigation receiving system is used to receive the navigation information of the navigation satellite constellation, and obtain the time information of the standard time according to the received navigation information as the benchmark for the satellite-ground time system calibration, that is, receive by configuring the high-orbit GNSS navigation system. The GNSS navigation signal transmitted across the earth, calculate the distance between the navigation satellite and the navigation message and other information, and obtain the time information of the satellite's current time; the high-orbit GNSS navigation receiving system converts the obtained time information of the standard time into hardware second pulse information The whole-second time code corresponding to the second pulse information; the high-orbit GNSS navigation receiving system transmits the converted hardware second pulse information to the highly stable clock source through the signal line, and the high-orbit GNSS navigation receiving system will convert the hardware second pulse information corresponding to the whole second. The second time code is transmitted to a highly stable clock source through the bus (commonly used bus is 1553B or CAN bus);

The highly stable clock source receives the hardware second pulse information and the whole second time code transmitted by the high-orbit GNSS navigation receiving system, and uses the received hardware second pulse information and the whole second time code through the internal timing module to calibrate the internal high stability clock source. According to the received hardware second pulse information of the high-orbit GNSS navigation receiving system, the high-stability clock of the high-stability clock source uses the clock taming module to correct the high-stability clock. Long-term clock drift (frequency difference compensation, phase compensation, etc.) to ensure long-term clock stability of highly stable clocks;

The high-stability clock source converts the generated time reference used on the satellite into the hardware second pulse information and the whole second time code corresponding to the hardware second pulse, respectively, and transmits it to the high-precision time requiring high precision through the signal line and the bus. The application requires a bus terminal, and the bus terminal provides time calibration for high-precision applications that require high time accuracy. The highly stable clock source is also used for time calibration of the data management system through the bus. First, the data management system sends the current time reference of the data management system to the highly stable clock source through the bus. The time base calibrates the time base of the data management system, and transmits the time difference to the data management system through the bus.

The high-stable clock source maintains the generated time reference used on the satellite through the time-keeping module, and utilizes its own high-stable clock characteristics, in the high-orbit GNSS navigation receiving system for a long time without second pulse information and whole time. Maintain the accuracy of its own time information when using the second time code.

The high-stable clock source outputs stable clock signals to other satellite systems or devices (including high-orbit GNSS navigation systems, data management systems, bus terminals required for high-precision applications, etc.) that require high-stable clocks.

The data management system communicates with a highly stable clock source through the bus to complete the time calibration, and obtains a regular precision time reference for maintaining satellite operation through the time calibration (accuracy is generally 1-10 ms). The calibration method is: the data management system transmits its own time code to the highly stable clock source, and the highly stable clock source compares the time code transmitted by the received data management system with the time reference maintained in the highly stable clock source to obtain the time difference information , and then feed back the obtained time difference information to the data management system, and the data management system calibrates the time information inside the data management system according to the received time difference information, obtains the calibrated time information, and maintains the time of the regular accuracy inside the data management system. benchmark. The data management system broadcasts the conventional precision time reference acquired and maintained by itself to the bus terminal of conventional precision application requirements through the bus (generally 1553B bus or CAN bus).

The conventional precision application requires that the bus terminals receive the conventional precision time reference broadcast by the data management system through the bus, as the time reference of these bus terminals.

The high-precision application requires bus terminals to receive hardware second pulse information and whole-second time codes sent by a highly stable clock source through signal lines and buses, and obtain a high-precision time reference as the time reference for these bus terminals.

The bus terminal required by the conventional precision application is generally a bus terminal for maintaining the basic operation of the satellite, including the thermal control sub-system, the measurement and control sub-system, the data transmission sub-system and other systems for the operation of the satellite platform;

The bus terminal required for high-precision applications is generally involved in payload imaging applications and ensuring imaging quality, including payload subsystems, control subsystems, and other subsystems that require high time accuracy. Satellite payload imaging related systems. The bus terminal required by high-precision applications uses the highly stable clock signal provided by the highly stable clock source;

The bus terminals are all used as users of time.

The equipment for receiving the second pulse includes a highly stable clock source, data management system, high-precision application demand bus terminal, etc. The signal using the second pulse is led out to the surface of the device through the device connector, which is convenient for receiving and using the second pulse. Pulse delay accuracy is tested and corrected to increase its high-precision measurability and ensure the accuracy and reliability of this high-precision time application.

A method for on-board time synchronization of a high-orbit remote sensing satellite, the steps of the method include:

The first step, the described high-orbit GNSS navigation receiving system receives the navigation information of the navigation satellite constellation, and obtains the time information of the standard time according to the received navigation information, as the benchmark of the satellite-earth time system calibration;

In the second step, the high-orbit GNSS navigation receiving system converts the obtained time information of standard time into hardware second pulse information and the whole-second time code corresponding to the hardware second pulse information, and transmits the converted hardware second pulse information to the high-speed pulse through the signal line. Stable clock source, the high-orbit GNSS navigation receiving system transmits the whole second time code corresponding to the converted hardware second pulse information to the highly stable clock source through 1553B or CAN bus;

In the third step, the highly stable clock source receives the hardware second pulse information and the whole second time code transmitted by the high-orbit GNSS navigation receiving system, and calibrates the high stability clock source according to the received hardware second pulse information and the whole second time code The internal clock generates a time reference that can be used on the satellite, and maintains the generated time reference used on the satellite; the high-stability clock source also uses its high-stability clock to provide high-orbit GNSS navigation receiving systems. A stable clock signal that acts as a clock for its software and hardware to operate.

In the fourth step, the highly stable clock source converts the generated time reference used on the satellite into the hardware second pulse information and the whole second time code corresponding to the hardware second pulse information, and provides it to high-precision applications that require high time accuracy Require bus terminal use;

In the fifth step, the highly stable clock source performs time calibration with the data management system through the bus, and the data management system obtains the calibrated time information through the calibration of the highly stable clock source, and this time information can be used to maintain the routine of the satellite platform. The operation and maintenance of the bus terminal is required for precision applications;

In the sixth step, the data management system distributes the time information calibrated by the highly stable clock source to the bus terminals required by conventional precision applications by broadcasting;

In the seventh step, the high-stable clock source maintains the generated time reference used on the satellite through the time-keeping module, and utilizes its own high-stable clock characteristics to ensure that there are no seconds in the high-orbit GNSS navigation receiving system for a long time. Maintains its own time accuracy with pulse information and whole-second timecode.

The bus terminal required by the conventional precision application is generally a bus terminal for maintaining the basic operation of the satellite, including the thermal control sub-system, the measurement and control sub-system, the data transmission sub-system and other systems for the operation of the satellite platform;

The bus terminal required for high-precision applications is generally involved in payload imaging applications and guaranteed imaging, including payload subsystems, control subsystems, and other subsystems that require high time accuracy. Satellite payload imaging-related systems;

The high-precision application requires that the bus terminal, the high-orbit GNSS navigation receiving system, and the data management system use the high-stable clock signal provided by the high-stable clock source;

The bus terminal acts as a user of time.

(1) Time generation

The satellite time reference of the high-orbit remote sensing satellite on-board time synchronization system, receives the GNSS navigation signal from the opposite side of the earth through the high-orbit GNSS navigation receiving system, measures and calculates the current time moment, and converts the GNSS time into the time used by the satellite platform benchmark. The time accuracy can be guaranteed to be 1 to 50 μs.

(2) Time traceability and calibration of highly stable clocks

The time base of the highly stable clock of the high-orbit remote sensing satellite is aligned with the time base of the high-orbit GNSS. The alignment method adopts high-precision hardware second pulse transmission, and the time accuracy can be guaranteed to be at the level of ±1μs or even ns. While the hardware second pulse is transmitted, the whole second time code of the time reference of the high-orbit GNSS is transmitted to the highly stable clock source through the data bus of the satellite platform. This completes the precise transfer of the high-precision satellite-to-earth time reference to the highly stable clock source.

After the high-stability clock source receives the hardware second pulse, it uses the non-accumulation and irrelevance of the second pulse time accuracy to calibrate its punctuality accuracy and high-stability clock accuracy, and correct the accumulated time error caused by its long-term drift and high stability. The long-term drift deviation of the clock can be used to accurately correct the satellite time reference and the highly stable clock source.

(3) Punctuality and maintenance of high stability time

High-orbit remote sensing satellites are equipped with highly stable clocks, generally hydrogen masers, rubidium clocks or constant temperature crystal oscillators, to achieve the punctuality accuracy of the satellite platform. Taking a rubidium clock as an example, the 10MHz clock output has a long-term stability of ±1×10 ^-13 /day. By using this clock to keep time, the maximum time change of 1μs per day can be guaranteed. Since the high-orbit GNSS navigation receiving system receives weak navigation signals from the earth and has poor reliability, there may be irregular time discontinuities. transition dependency.

(4) Satellite platform for timing

High-orbit remote sensing satellites have some terminals that require high-precision time applications, mainly payload subsystems (such as optical payload subsystems of optical remote sensing satellites, microwave payload subsystems of microwave remote sensing satellites) and satellite attitude and orbit control accuracy requirements are high. Control subsystems, etc. These high-precision applications require the time base of the bus terminal to be aligned with the time base of a highly stable clock source. The alignment method adopts high-precision hardware second pulse transmission, and the time accuracy can be guaranteed to be ±1μs. While the hardware second pulse is transmitted, the whole second time code of the highly stable clock source reference is transmitted to the payload subsystem and the control subsystem through the data bus of the satellite platform. In this way, the precise calibration of the time system of the bus terminal required by the satellite high-precision application is completed.

High-orbit remote sensing satellite platforms generally have some terminals with low sensitivity to time accuracy. These terminals have nothing to do with the accuracy of the payload application, and are mainly used to ensure the basic and reliable operation of the satellite platform, such as measurement and control subsystems, thermal control subsystems, and overall circuits. Sub-systems, power sub-systems, data transmission sub-systems, digital control computers in the data management system, remote units, etc., these bus terminals that require conventional precision applications, can meet the time accuracy requirements through the data management system. First, the data management system is time-calibrated through a highly stable clock source. The time-calibration methods include forced time-calibration and autonomous time-calibration. Then, after the data management system is punctual, the measurement and control sub-system, thermal control sub-system, overall circuit sub-system, power supply sub-system, data transmission sub-system, digital control computer in the data management system, remote unit, etc. are monitored through the data bus. calibration.

(4) Satellite time system test interface

The timing accuracy of the high-orbit remote sensing satellite onboard time system can be guaranteed to 1μs or even ns level through hardware second pulse. When the bus terminal required by high-precision applications, such as the load sub-system and the control sub-system, after receiving the second pulse, through internal hardware and software processing, the final application of the second pulse accuracy has a certain delay. In order to confirm the accurate value of the delay accuracy, the high-precision application requires the final application of the second pulse of the bus terminal to be led to the test interface of the device through measures such as branching, so as to facilitate the direct measurement of the second pulse output from the high-orbit GNSS navigation system to the high-precision The application requires the accuracy of the time delay of pulses per second for the final application of the bus termination.

Example

As shown in Figure 1, a high-orbit microwave remote sensing satellite is equipped with a high-orbit GNSS navigation receiving system. , automatically obtain the time information of the current moment of the satellite, and complete the time synchronization with the ground systems through the BDS constellation and the GPS constellation. The clock required for the operation and calculation of the high-orbit GNSS navigation receiving system is provided and guaranteed by the high-stability clock of the high-stability clock source configured on the satellite. This step completes the time unification of the satellite and the ground.

The high-orbit GNSS navigation receiving system converts the acquired time information of standard time into hardware second pulse information and whole second time code corresponding to hardware second pulse information. The high-orbit GNSS navigation receiving system transmits the converted hardware second pulse information to the highly stable clock source through the signal line, and transmits the whole second time code corresponding to the converted hardware second pulse information to the high stability clock source through the 1553B bus. The highly stable clock source receives the hardware second pulse information and the whole second time code transmitted by the high-orbit GNSS navigation receiving system, and uses the received hardware second pulse information and the whole second time code through the internal timing module to calibrate the internal time information of the highly stable clock source , to generate a time reference that can be used on the satellite to complete the timing operation.

The highly stable clock source converts the generated time reference used on the satellite into hardware second pulse information and whole second time code, and transmits it to the high-precision applications that require high time accuracy through the signal line and the bus respectively. Bus terminal 1, bus terminal 2, ..., bus terminal n, such terminals on the remote sensing satellite include a payload subsystem and a control subsystem, and provide time calibration for the payload subsystem and the control subsystem through hardware second pulse and whole-second time code. The calibration accuracy can reach the order of μs.

The highly stable clock source is also used for time calibration of the data management system through the bus. First, the data management system sends the current time reference of the data management system to the highly stable clock source through the bus. The time base calibrates the time base of the data management system, and transmits the time difference to the data management system through the bus. The data management system communicates with the highly stable clock source through the bus to complete the timing action, and obtains the regular precision time reference for maintaining the satellite operation through timing (the precision is generally 1-10ms).

The data management system broadcasts the conventional precision time reference acquired and maintained by itself to the bus terminal a, bus terminal b, and bus terminal m required by the conventional precision application through the 1553B bus. Such terminals on the remote sensing satellite include measurement and control subsystems, thermal control subsystems, data transmission subsystems, overall circuit subsystems, control subsystems, remote units of data management systems, etc., and provide time calibration for these subsystems. The calibration accuracy can reach the order of ms.

The high-stability clock source maintains the generated time reference used on the satellite through the punctuality module, and utilizes its own high-stability clock characteristics, in the high-orbit GNSS navigation receiving system, there is no second pulse information and whole-second time code for a long time. maintain the accuracy of its own time. Since the high-orbit GNN navigation receiving system receives the navigation signals of the navigation constellation opposite the earth, these navigation signals are the signals leaked from the side lobes of the navigation star, and the navigation receiving system may lose lock for tens of minutes to several hours. The navigation receiving system cannot provide the high-stability clock source with the second pulse signal and the corresponding whole-second time code. At this time, the high-stability clock source uses its own high-stability clock to extrapolate and maintain the time information maintained by itself.

The highly stable clock of the highly stable clock source uses the clock taming module to correct the long-term clock drift (frequency difference compensation, phase compensation, etc.) of the highly stable clock source according to the received hardware second pulse information of the high-orbit GNSS navigation receiving system to ensure a highly stable clock clock stability.

The highly stable clock source outputs a stable clock signal to other satellite systems or devices that require a highly stable clock.

To sum up, the above are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. a high-orbit remote sensing satellite on-board time synchronization system is characterized in that: this on-board time synchronization system comprises a high-orbit GNSS navigation receiving system, a highly stable clock source, a data management system and a bus terminal; The bus terminal is divided into a high-precision application demand bus terminal and a conventional precision application demand bus terminal; the time precision of the high-precision application demand bus terminal is on the order of μs; the conventional precision application demand bus terminal The time precision of the bus terminal is the amount of ms class; The described high-orbit GNSS navigation receiving system is used to receive the navigation information of the navigation satellite constellation, and obtains the time information of the standard time according to the received navigation information as the benchmark of the satellite-earth time system calibration; The high-orbit GNSS navigation receiving system converts the time information of the acquired standard time into the hardware second pulse information and the whole second time code corresponding to the hardware second pulse information; The high-orbit GNSS navigation receiving system transmits the converted hardware second pulse information to a highly stable clock source through a signal line; The high-orbit GNSS navigation receiving system transmits the whole-second time code corresponding to the converted hardware second pulse information to a highly stable clock source through the bus; The highly stable clock source is used to receive the hardware second pulse information and the whole second time code transmitted by the high-orbit GNSS navigation receiving system, and use the received hardware second pulse information and the whole second time code to calibrate the internal clock to generate a clock that can be used as a clock. the time base used on the star; The highly stable clock source converts the generated time reference used on the satellite into hardware second pulse information and whole second time code. The hardware second pulse information is transmitted to the high-precision application demand bus terminal through the signal line, and the whole second time code passes through The bus is passed to the bus terminal of high-precision application requirements, providing a time reference for the bus terminal of high-precision application requirements; The data management system sends the current time of the data management system to the highly stable clock source through the bus, and the highly stable clock source calibrates the current time of the data management system by using the generated time reference used on the satellite, produces the time difference of the time calibration, and generates a The time difference is transmitted to the data management system through the bus, and the data management system completes the time calibration according to the received time difference, and sends the calibrated time to the bus terminal required by conventional precision applications to provide time for the bus terminal required by conventional precision applications. benchmark. 2. a kind of high-orbit remote sensing satellite on-board time synchronization system according to claim 1, is characterized in that: The high-precision application requires the time precision of the bus terminal to be 1-40 μs, and the conventional precision application requires the time precision of the bus terminal to be 1-10 ms. 3. a kind of high-orbit remote sensing satellite on-board time synchronization system according to claim 1, is characterized in that: The high-stability clock source also corrects the long-term clock drift of the high-stability clock according to the received hardware second pulse information of the high-orbit GNSS navigation receiving system. 4. a kind of high-orbit remote sensing satellite on-board time synchronization system according to claim 1, is characterized in that: The bus terminal required by the conventional precision application is used to maintain the normal operation of the satellite, and receive the conventional precision time reference broadcast by the data management system through the bus, as the time reference of these bus terminals, including the thermal control sub-system, the measurement and control sub-system , Data transmission subsystem, etc. 5. a kind of high-orbit remote sensing satellite on-board time synchronization system according to claim 1, is characterized in that: The bus terminal required for high-precision applications participates in payload imaging applications and ensures imaging quality, including payload subsystems, control subsystems, and other subsystems that require high time accuracy. 6. a kind of high-orbit remote sensing satellite on-board time synchronization system according to claim 1, is characterized in that: The method for the high-orbit GNSS navigation receiving system to obtain the time information of the standard time according to the received navigation information is: by configuring the high-orbit GNSS navigation system to receive the GNSS navigation signal transmitted across the earth, and to calculate the distance and the navigation star. Navigation messages and other information to obtain the time information of the current time of the satellite. 7. A high-orbit remote sensing satellite on-board time synchronization method is characterized in that the steps of the method comprise: In the first step, the high-orbit GNSS navigation receiving system receives the navigation information of the navigation satellite constellation, and obtains the time information of the standard time according to the received navigation information, which is used as the benchmark for the satellite-earth time system calibration; In the second step, the high-orbit GNSS navigation receiving system converts the obtained time information of standard time into hardware second pulse information and the whole-second time code corresponding to the hardware second pulse information, and transmits the converted hardware second pulse information to the high-speed pulse through the signal line. Stable clock source, the high-orbit GNSS navigation receiving system transmits the whole second time code corresponding to the converted hardware second pulse information to the highly stable clock source through the bus; In the third step, the highly stable clock source receives the hardware second pulse information and the whole second time code transmitted by the high-orbit GNSS navigation receiving system, and calibrates the internal clock of the highly stable clock source according to the received hardware second pulse information and the whole second time code. , generate a time reference that can be used on the satellite, and maintain the generated time reference used on the satellite; the highly stable clock source also uses its highly stable clock to provide a highly stable clock for the high-orbit GNSS navigation receiving system Signal; In the fourth step, the high-stability clock source converts the generated time reference used on the satellite into the hardware second pulse information and the whole second time code corresponding to the hardware second pulse information, and provides it to the bus terminal for high-precision applications that require high time accuracy. use; In the fifth step, the highly stable clock source performs time calibration with the data management system through the bus, and the data management system obtains the calibrated time information through the calibration of the highly stable clock source, and maintains the time reference of conventional precision inside the data management system; In the sixth step, the data management system distributes the time information calibrated by the high-stable clock source to the bus terminal for use by conventional precision applications through broadcasting; In the seventh step, the highly stable clock source maintains the generated time reference used on the satellite on time; The eighth step, the high-stability clock source uses the hardware second pulse information of the high-orbit GNSS navigation receiving system to correct the long-term clock drift of the high-stability clock; The ninth step, the high-stability clock source provides the high-stability clock signal to the system on the satellite that needs to use the high-stability clock.

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