Optimal transfer method of frequency drift rate of navigation satellite on-orbit master and backup clock

Abstract

The application provides a navigation satellite on-orbit operation main and backup clock frequency drift rate optimal transfer method, comprising: combining satellite-ground two-way ranging observation data, using satellite-ground two-way comparison method to calculate a plurality of main clock difference parameters; through on-orbit navigation satellite downlink engineering telemetry data, obtaining the clock difference parameters of the hot backup clock relative to the main clock; calculating a plurality of hot backup clock difference parameters; in the main and backup clock following state, the phase and frequency of the hot backup clock are equal to the phase and frequency of the main clock and change synchronously with time; after the on-orbit navigation satellite is stably operated, the frequency drift rate of the satellite clock difference data is a constant, the hot backup clock difference parameters are uploaded to the on-orbit navigation satellite storage; when the on-orbit navigation satellite autonomously monitors that the main clock and the hot backup clock are switched, the stored hot backup clock difference parameters are directly and autonomously called to replace the main clock difference parameters as the satellite clock difference data, the satellite clock difference data after switching is compensated, and the frequency drift rate of the satellite clock difference data is corrected.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of spaceborne atomic clock, in particular to a navigation satellite in-orbit operation master-slave clock frequency drift rate optimal transfer method. BACKGROUND

[0002] With the continuous development of satellite navigation positioning, satellite communication and other fields, the requirements of satellite payload for time and frequency accuracy are becoming higher and higher. Satellite navigation system can provide high-precision, high-reliability positioning, navigation, timing services for all kinds of users all over the world, all day and all year round, which is related to national security and economic development. Precise time keeping technology is the technical basis for satellite navigation system to provide high-precision positioning, navigation, timing services. At present, satellite navigation system is equipped with precise atomic clock, and the atomic clock of each monitoring station and master station is always kept in precise synchronization, so as to provide precise navigation and timing services for users.

[0003] In order to ensure the stability and reliability of navigation satellite system, the satellite-borne time and frequency processing system of navigation satellite adopts redundant backup architecture design, and two atomic clocks are used to work at the same time, one of which is in master working state and the other is in hot backup working state. When the master working atomic clock appears abnormal or fails, the system can automatically and smoothly switch to the hot backup atomic clock, so as to ensure the continuity of navigation satellite frequency signal. In order to ensure that the system output time and frequency reference signal does not have large jitter and change before and after the master-slave atomic clock switching, the system uses phase comparator to measure the phase difference of master-slave atomic clock, and adjusts the control of hot backup atomic clock signal to follow the master atomic clock according to the measured phase difference data through phase control word and frequency control word, as shown in Figure 1 .

[0004] At present, the smooth switching technology of master-slave clock can only realize the smooth switching of a0(phase difference) and a1(clock speed) in clock difference parameters, but cannot realize the switching of a2(frequency drift) in clock difference parameters, so it cannot realize the optimal performance transfer of master-slave clock. The clock difference model of in-orbit navigation satellite is △t=a0+a1τ+a2τ 2 , where △t is clock difference, τ is time, a0 is phase, a1 is frequency, and a2 is frequency drift rate. The accuracy of satellite clock clock difference parameter measurement and its long-term consistency directly affect the accuracy of satellite navigation and positioning. At present, in order to ensure the stability and reliability of navigation satellite system, the satellite-borne time and frequency processing system of navigation satellite adopts redundant backup architecture design, and two atomic clocks are used to work at the same time, one of which is in master working state and the other is in hot backup working state. When the master working atomic clock appears abnormal or fails, the system can automatically and smoothly switch to the hot backup atomic clock, so as to ensure the continuity of navigation satellite frequency signal. In order to ensure that the system output time and frequency reference signal does not have large jitter and change before and after the master-slave atomic clock switching, the system uses phase comparator to measure the phase difference of master-slave atomic clock, and adjusts the control of hot backup atomic clock signal to follow the master atomic clock according to the measured phase difference data through phase control word and frequency control word, as shown in 0备 . 1备 . 0主 .1主 To maintain consistency, while the frequency drift rate a of the hot-backup atomic clock. 2备 Frequency drift rate a of the primary atomic clock 2主 They are different. Therefore, when the primary atomic clock malfunctions or fails, the navigation satellite system automatically switches to the hot backup atomic clock. Only the phase a0 and frequency a1 of the primary and backup clocks can be transferred, but the frequency drift rate a2 cannot be transferred. Before and after the primary / backup clock switch, the frequency drift rate a2 changes abruptly, preventing the optimal transfer of satellite clock performance.

[0005] According to the clock bias model, after a primary / backup clock switch occurs in an on-orbit navigation satellite, if the ground cannot promptly update the new clock bias parameters, the frequency drift rate a2 will jump, causing the clock bias prediction error to increase quadratically with the integration time. This has a significant impact on long-term clock bias prediction; for example, the prediction error over 48 hours can reach tens of nanoseconds. This severely affects the timing accuracy of navigation satellites and significantly limits the autonomous navigation capability of the navigation satellite system. Therefore, there is an urgent need for an optimal performance transfer technology for on-orbit navigation satellite primary / backup clock switchover. Summary of the Invention

[0006] The purpose of this invention is to provide an optimal method for transmitting the frequency drift rate of the primary and backup clocks during on-orbit operation of navigation satellites, so as to solve the problem that the transmission of the frequency drift rate of the primary and backup clocks cannot be achieved when the existing navigation satellite system automatically switches to hot backup atomic clock operation.

[0007] To address the aforementioned technical problems, this invention provides a method for optimal transmission of primary and backup clock frequency drift rates during on-orbit operation of navigation satellites. This method includes:

[0008] Step 1: The on-orbit navigation satellite uses two atomic clocks that are powered on simultaneously. One of the atomic clocks serves as the master clock and is in primary working state, while the other atomic clock serves as the hot standby clock and is in hot backup working state.

[0009] By combining satellite-to-ground two-way ranging observation data, multiple master clock difference parameters are calculated using the satellite-to-ground two-way comparison method.

[0010] Step 2: Obtain the clock difference parameters between the hot standby clock and the master clock using the engineering telemetry data broadcast from the on-orbit navigation satellite;

[0011] Step 3: Using the onboard primary and backup atomic clock phase comparison method, multiple hot backup clock bias parameters are calculated based on the primary clock bias parameters and the engineering telemetry data.

[0012] Step 4: In the master-slave clock following state, the phase and frequency of the hot standby clock remain equal to the phase and frequency of the master clock and change synchronously with time, enabling seamless switching;

[0013] After the in-orbit navigation satellite is stabilized, the frequency drift rate of the satellite clock difference data is constant, and the hot backup clock difference parameter is uploaded to the in-orbit navigation satellite for storage as a backup;

[0014] In step five, when the in-orbit navigation satellite autonomously detects that the main clock is switched to the hot backup clock, the stored hot backup clock difference parameter is directly and autonomously called to replace the main clock difference parameter as satellite clock difference data, the frequency drift rate of the satellite clock difference data is compensated, and the satellite clock difference data is corrected.

[0015] Optionally, in the optimal transfer method of the frequency drift rates of the main and backup clocks of the navigation satellite in the in-orbit operation, the downlink signal used in the satellite-ground two-way ranging is a satellite signal output after frequency reduction processing by a high-frequency head, and the frequency is 950 MHZ-2150 MHZ.

[0016] Optionally, in the optimal transfer method of the frequency drift rates of the main and backup clocks of the navigation satellite in the in-orbit operation, the main clock difference parameters are calculated by using a satellite-ground two-way comparison method in combination with satellite-ground two-way ranging observation data, and the main clock difference parameters include:

[0017] A ground control system taking a ground reference atomic clock as a reference transmits an uplink signal to establish an uplink ranging link with a satellite, and the satellite takes a main clock of an on-board atomic clock as a reference. Meanwhile, the satellite transmits a downlink signal to establish a downlink ranging link with the ground control system. The satellite measures an uplink pseudo-range value between the satellite and the ground, and the ground control system measures a downlink pseudo-range value between the satellite and the ground.

[0018] The uplink pseudo-range value is returned to the ground control system through telemetry. The ground control system calculates a clock difference of the main clock relative to the ground reference atomic clock within a sampling period according to the downlink pseudo-range value and the uplink pseudo-range value.

[0019] Optionally, in the optimal transfer method of the frequency drift rates of the main and backup clocks of the navigation satellite in the in-orbit operation, the main clock difference parameters are calculated by using a satellite-ground two-way comparison method in combination with satellite-ground two-way ranging observation data, and the main clock difference parameters further include:

[0020] The uplink pseudo-range value measured by the satellite is a sum of a microwave propagation time delay between the satellite and the ground and a clock difference of the main clock relative to the ground reference atomic clock;

[0021] The downlink pseudo-range value measured by the ground control system is a difference between the microwave propagation time delay between the satellite and the ground and the clock difference of the main clock relative to the ground reference atomic clock;

[0022] The microwave propagation time delay between the satellite and the ground contained in the uplink pseudo-range value and the microwave propagation time delay between the satellite and the ground contained in the downlink pseudo-range value are equal within the same sampling period.

[0023] Optionally, in the navigation satellite in-orbit operation master backup clock frequency drift rate optimal transfer method, the clock difference parameter of the hot backup clock relative to the master clock is obtained through the engineering telemetry data broadcast by the in-orbit navigation satellite.

[0024] The satellite time-frequency processing system measures and records the clock difference of the hot backup clock relative to the master clock in real time.

[0025] Optionally, in the navigation satellite in-orbit operation master backup clock frequency drift rate optimal transfer method, the clock difference of the hot backup clock relative to the master clock measured and recorded by the satellite time-frequency processing system is the phase difference between the hot backup clock output signal and the master clock output signal.

[0026] The phase difference between the hot backup clock output signal and the master clock output signal measured by the phase discriminator of the satellite-borne time-frequency processing system is the clock difference of the hot backup clock relative to the master clock.

[0027] Optionally, in the navigation satellite in-orbit operation master backup clock frequency drift rate optimal transfer method, the on-board master backup atomic clock phase comparison method is adopted, and a plurality of hot backup clock difference parameters are calculated according to the master clock difference parameter and the engineering telemetry data.

[0028] The clock difference of the hot backup clock relative to the master clock is returned to the ground operation and control system through telemetry, and the ground operation and control system obtains the clock difference of the hot backup clock relative to the ground reference atomic clock according to the clock difference of the master clock relative to the ground reference atomic clock and the clock difference of the hot backup clock relative to the master clock.

[0029] Optionally, in the navigation satellite in-orbit operation master backup clock frequency drift rate optimal transfer method, the uplink pseudo-range value and the clock difference of the hot backup clock relative to the master clock are both transmitted to the ground in real time through the satellite-ground measurement and control channel, and are collected to the ground operation and control system for data processing to obtain the clock difference of the master clock relative to the ground reference atomic clock and the clock difference of the hot backup clock relative to the ground reference atomic clock.

[0030] In the optimal transfer method of the frequency drift rate of the main and backup clocks of the navigation satellite in orbit provided by the application, the multiple hot backup clock difference parameters are calculated according to the main clock difference parameters and engineering telemetry data, the hot backup clock difference parameters are uploaded to the storage backup of the navigation satellite in orbit, when the navigation satellite in orbit autonomously monitors that the main clock and the hot backup clock are switched, the stored hot backup clock difference parameters are directly and autonomously called to replace the main clock difference parameters as the satellite clock difference data, the satellite clock difference data after switching is compensated, the frequency drift rate of the satellite clock difference data is corrected, and the optimal performance transfer during the switching of the main and backup clocks of the satellite is realized. Therefore, the application provides an optimal performance transfer technology for the switching of the main and backup clocks of the navigation satellite in orbit, and can realize the optimal transfer of the phase, frequency and frequency drift rate during the switching of the main and backup clocks in orbit, improve the long-term clock difference prediction accuracy by one order of magnitude, and improve the autonomous navigation operation capability of the navigation satellite. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a schematic diagram of the existing optimal transfer method of the frequency drift rate of the main and backup clocks of the navigation satellite in orbit;

[0032] Figure 2 is a schematic diagram of the clock difference change of the main and backup clocks of the existing optimal transfer method of the frequency drift rate of the main and backup clocks of the navigation satellite in orbit;

[0033] Figure 3 is a schematic diagram of the optimal transfer method of the frequency drift rate of the main and backup clocks of the navigation satellite in orbit according to an embodiment of the application;

[0034] In the drawings: 10-main clock; 20-hot backup clock; 30-power supply; 40-frequency synthesizer; 50-phase comparator; 60-controller; 70-switching matrix. DETAILED DESCRIPTION

[0035] The optimal transfer method of the frequency drift rate of the main and backup clocks of the navigation satellite in orbit provided by the application will be further described below in combination with the drawings and specific embodiments. The advantages and features of the application will be clearer according to the following description and claims. It should be noted that the drawings are very simplified and use non-precise proportions, and are only used to facilitate and clarify the purpose of assisting in the description of the embodiments of the application.

[0036] The core idea of the application is to provide an optimal transfer method of the frequency drift rate of the main and backup clocks of the navigation satellite in orbit, so as to solve the problem that the existing navigation satellite system cannot realize the transfer of the frequency drift rate of the main and backup clocks when automatically switching to the hot backup atomic clock.

[0037] To realize the above idea, the application provides a navigation satellite in-orbit operation master-slave clock frequency drift rate optimal transfer method, which comprises the following steps: step one, two atomic clocks are used to work simultaneously in the in-orbit navigation satellite, one of which is used as a master clock and is in a master working state, and the other is used as a hot standby clock and is in a hot standby working state; a plurality of master clock difference parameters are calculated by using a star-ground two-way comparison method in combination with star-ground two-way ranging observation data; step two, the clock difference parameters of the hot standby clock relative to the master clock are obtained through the engineering telemetry data broadcast by the in-orbit navigation satellite; step three, a plurality of hot standby clock difference parameters are calculated by using a star master-slave atomic clock phase comparison method according to the master clock difference parameters and the engineering telemetry data; step four, in the master-slave clock following state, the phase and frequency of the hot standby clock are kept equal to and change synchronously with the phase and frequency of the master clock, so that seamless switching can be realized; after the in-orbit navigation satellite is stably operated, the frequency drift rate of the satellite clock difference data is a constant, and the hot standby clock difference parameters are uploaded to the in-orbit navigation satellite for storage; step five, when the in-orbit navigation satellite autonomously monitors that the master clock and the hot standby clock are switched, the hot standby clock difference parameters stored are directly called autonomously to replace the master clock difference parameters as satellite clock difference data, the satellite clock difference data after switching is compensated, and the frequency drift rate of the satellite clock difference data is corrected.

[0038] The in-orbit navigation satellite clock difference model is △t=a0+a1τ+a2τ 2 , wherein △t is the clock difference, τ is the time, a0 is the phase, a1 is the frequency, and a2 is the frequency drift rate.

[0039] At present, in order to ensure the stability and reliability of the navigation satellite system, a redundant backup architecture design is adopted for the satellite-borne time-frequency processing system of the navigation satellite, as shown in the figure. Figure 1 The power supply 30 supplies power to the entire system, two atomic clocks are used to work simultaneously, one of which is in a master working state (master clock / primary atomic clock 10) and the other is in a hot standby working state (hot standby clock / hot standby atomic clock 20), the master-slave clocks are in a tracking enabled state, the phase and frequency of the hot standby clock 20 are kept in a following state (achieved by a frequency synthesizer 40 and a controller 60, a phase comparator 50 is used to monitor the clock difference data between the master-slave clocks, according to the clock difference data, the frequency synthesizer 40 and the controller 60 jointly control the hot standby clock 20 to follow the master clock 10, so that the phase and frequency parameters of the master-slave clocks are kept the same), and the system output frequency is achieved by a switch matrix 70, that is, the standby clock phase a 0备 and the frequency a 1备 are kept equal to the master clock phase a 0主 and the frequency a 1主 , but the standby clock frequency drift rate a2备 and the frequency drift rate a2 of the main clock 2主 are not equal. Therefore, when the main clock is abnormal or fails, and the satellite switches to the backup clock, only the phase a0 and the frequency a1 of the main clock and the backup clock can be transferred, but the frequency drift rate a2 cannot be transferred. Since the frequency drift rate a2 of the backup clock is different from that of the main clock 2备 and the frequency drift rate a2 of the main clock 2主 are not equal, after the satellite switches from the main clock to the backup clock, the frequency drift rate a2 jumps, and the optimal performance of the satellite clock cannot be transferred, as shown in FIG. 1 (switching from the main clock to the backup clock at t0), when the ground station cannot timely upload the new clock difference parameters, the clock difference parameters a Figure 2 used by the satellite are seriously inconsistent with the actual clock difference parameters a 2主 used by the satellite after switching to the backup clock, and the long-term clock difference prediction error increases quadratically with the integral time. 2备

[0040] In order to achieve the optimal transfer of the phase a0, the frequency a1 and the frequency drift rate a2 when the main clock and the backup clock are switched on the satellite, after the navigation satellite atomic clock is stably operated, the clock difference parameters (a 0备 -a 0主 ), (a 1备 -a 1主 ) and (a 2备 -a 2主 ) of the backup clock relative to the main clock are obtained through the engineering telemetry data "main-backup clock phase difference" broadcast by the navigation satellite on orbit. Combined with the L-band satellite-ground two-way ranging observation data, the main clock difference parameters a 0主 , a 1主 and a 2主 can be calculated by using the satellite-ground two-way comparison method, and then the backup clock difference parameters a 0备 , a 1备 and a 2备 can be calculated by using the on-satellite main-backup atomic clock phase comparison method. Since the phase a 0备 and the frequency a 1备 of the backup clock follow the state of the main clock and keep equal to the phase a 0主 and the frequency a 1主 of the main clock and change synchronously with time, seamless switching can be achieved, and the frequency drift rate of the satellite atomic clock is basically a constant after stable operation, so only the calculated backup clock difference parameters a 2备 are uploaded to the satellite for storage as backup. When the satellite autonomously monitors the switching of the main clock and the backup clock, the stored backup clock difference parameters a 2备 are directly called to replace the original main clock difference parameters a 2主 , the satellite clock difference data after switching is compensated, the frequency drift rate is corrected, and the optimal performance transfer of the satellite main clock and the backup clock is achieved.

[0041] <Embodiment I> ​

[0042] The embodiment provides a navigation satellite in-orbit operation master and backup clock frequency drift rate optimal transfer method. Figure 3 As shown in the figure, the navigation satellite in-orbit operation master and backup clock frequency drift rate optimal transfer method comprises the following steps: step one, the in-orbit navigation satellite adopts two atomic clocks to work simultaneously, one of which is a master clock 10 in a master working state, and the other is a hot backup clock 20 in a hot backup working state; a plurality of master clock difference parameters a 0主 , a 1主 and a 2主 are calculated by using a star-ground two-way comparison method combined with star-ground two-way ranging observation data; step two, clock difference parameters (a 0备 -a 0主 ), (a 1备 -a 1主 ) and (a 2备 -a 2主 ) of the hot backup clock relative to the master clock are obtained through engineering telemetry data broadcast by the in-orbit navigation satellite; step three, a plurality of hot backup clock difference parameters a 0备 , a 1备 and a 2备 are calculated by using a star-based master and backup atomic clock phase comparison method according to the master clock difference parameters and the engineering telemetry data; step four, in the master and backup clock following state, the phase and frequency a 0备 and a 1备 of the hot backup clock remain equal to and change synchronously with the phase and frequency a 0主 and a 1主 of the master clock, and seamless switching can be realized; after the in-orbit navigation satellite is stably operated, the frequency drift rate of satellite clock difference data is a constant, the hot backup clock difference parameter a 2备 is uploaded to the in-orbit navigation satellite storage backup; step five, when the in-orbit navigation satellite autonomously monitors that the master clock and the hot backup clock are switched, the stored hot backup clock difference parameter a 2备 is directly and autonomously called to replace the master clock difference parameter a 2主 as satellite clock difference data, the satellite clock difference data after switching is compensated, and the frequency drift rate of the satellite clock difference data is corrected.

[0043] Specifically, in the navigation satellite in-orbit operation master and backup clock frequency drift rate optimal transfer method, the downlink signal used in the satellite-ground two-way ranging is a satellite signal output after frequency reduction processing by a high frequency head, and the frequency is 950 MHZ-2150 MHZ. In the navigation satellite in-orbit operation master and backup clock frequency drift rate optimal transfer method, a plurality of master clock difference parameters are calculated by using a satellite-ground two-way comparison method combined with satellite-ground two-way ranging observation data, including: taking a ground reference atomic clock as a reference, a ground operation and control system transmits an uplink signal to establish an uplink ranging link with a satellite, the satellite takes a master clock of a satellite-borne atomic clock as a reference, and the satellite transmits a downlink signal to establish a downlink ranging link with the ground operation and control system, the satellite measures an uplink pseudo-range value between the satellite and the ground, and the ground operation and control system measures a downlink pseudo-range value between the satellite and the ground; the uplink pseudo-range value is returned to the ground operation and control system through telemetry, and the ground operation and control system calculates a clock difference of the master clock relative to the ground reference atomic clock in a sampling period according to the downlink pseudo-range value and the uplink pseudo-range value.

[0044] Further, in the navigation satellite in-orbit operation master and backup clock frequency drift rate optimal transfer method, the plurality of master clock difference parameters calculated by using the satellite-ground two-way comparison method combined with satellite-ground two-way ranging observation data further include: the uplink pseudo-range value measured by the satellite between the satellite and the ground is the sum of a microwave propagation time delay between the satellite and the ground and a clock difference of the master clock relative to the ground reference atomic clock; the downlink pseudo-range value measured by the ground operation and control system between the satellite and the ground is the difference between the microwave propagation time delay between the satellite and the ground and the clock difference of the master clock relative to the ground reference atomic clock; and the satellite-ground microwave propagation time delay contained in the uplink pseudo-range value and the satellite-ground microwave propagation time delay contained in the downlink pseudo-range value are equal in the same sampling period.

[0045] In addition, in the navigation satellite in-orbit operation master and backup clock frequency drift rate optimal transfer method, the clock difference parameter of the hot backup clock relative to the master clock is obtained through engineering telemetry data broadcast by the in-orbit navigation satellite, including: a satellite time-frequency processing system measures and records the clock difference of the hot backup clock relative to the master clock in real time. In the navigation satellite in-orbit operation master and backup clock frequency drift rate optimal transfer method, the clock difference of the hot backup clock relative to the master clock measured and recorded by the satellite time-frequency processing system is the difference between the phase of the hot backup clock output signal and the phase of the master clock output signal; the phase difference between the hot backup clock output signal and the master clock output signal is measured by a phase discriminator of the satellite-borne time-frequency processing system, and the clock difference of the hot backup clock relative to the master clock is obtained.

[0046] Specifically, in the navigation satellite in orbit operation main and backup clock frequency drift rate optimal transfer method, the on-board main and backup atomic clock phase comparison method is adopted, and according to the main clock difference parameters and the engineering telemetry data, a plurality of hot backup clock difference parameters are calculated, including: the hot backup clock difference relative to the main clock is returned to the ground operation and control system through telemetry, and the ground operation and control system obtains the hot backup clock difference relative to the ground reference atomic clock according to the clock difference of the main clock relative to the ground reference atomic clock and the clock difference of the hot backup clock relative to the main clock. In the navigation satellite in orbit operation main and backup clock frequency drift rate optimal transfer method, the uplink pseudo-range value and the clock difference of the hot backup clock relative to the main clock are both transmitted to the ground in real time through the satellite-ground measurement and control channel, and are collected to the ground operation and control system for data processing to obtain the clock difference of the main clock relative to the ground reference atomic clock and the clock difference of the hot backup clock relative to the ground reference atomic clock.

[0047] In the navigation satellite in orbit operation main and backup clock frequency drift rate optimal transfer method provided by the application, a plurality of hot backup clock difference parameters are calculated according to the main clock difference parameters and the engineering telemetry data, and the hot backup clock difference parameters are uploaded to the in-orbit navigation satellite storage backup. When the in-orbit navigation satellite autonomously monitors that the main clock and the hot backup clock are switched, the stored hot backup clock difference parameters are directly and autonomously called to replace the main clock difference parameters as satellite clock difference data, the satellite clock difference data after switching is compensated, the frequency drift rate of the satellite clock difference data is corrected, and the optimal performance transfer of the satellite main and backup clock switching is realized. Therefore, the application provides an in-orbit navigation satellite main and backup clock switching optimal performance transfer technology, which can realize optimal transfer of phase, frequency and frequency drift rate during in-orbit main and backup clock switching, improve long-term clock difference prediction accuracy by one order of magnitude, and improve the autonomous navigation operation capability of the navigation satellite.

[0048] In summary, the above embodiments have described in detail the different configurations of the navigation satellite in orbit operation main and backup clock frequency drift rate optimal transfer method. Of course, the application includes but is not limited to the configurations listed in the above embodiments. Any transformation based on the configurations provided in the above embodiments belongs to the scope of protection of the application. Those skilled in the art can make further inferences based on the above embodiments.

[0049] The above description is only a description of the preferred embodiments of the application, and does not limit the scope of the application. Any modification or modification of the application by those skilled in the art based on the above disclosure is within the scope of protection of the claims.

Claims

1. A navigation satellite in-orbit master-slave clock frequency drift rate optimal transfer method, characterized in that, The method comprises the following steps: Step 1, two atomic clocks on the in-orbit navigation satellite are powered on at the same time, one of which is a master clock in a main working state, and the other is a hot standby clock in a hot standby working state; Step 2, the clock difference parameters of the master clock are calculated by using a satellite-ground two-way comparison method combined with satellite-ground two-way ranging observation data; Step 3, the clock difference parameters of the hot standby clock relative to the master clock are obtained through the engineering telemetry data broadcast by the in-orbit navigation satellite; Step 4, the clock difference parameters of the hot standby clock are calculated by using a satellite onboard master-slave atomic clock phase comparison method according to the clock difference parameters of the master clock and the engineering telemetry data; Step 5, in the master-slave clock following state, the phase and frequency of the hot standby clock remain equal to and synchronous with the phase and frequency of the master clock, and seamless switching can be realized; After the in-orbit navigation satellite is stably operated, the frequency drift rate of the satellite clock difference data is a constant, the clock difference parameters of the hot standby clock are uploaded to the in-orbit navigation satellite for storage as a backup; Step 5, when the in-orbit navigation satellite autonomously monitors that the master clock and the hot standby clock are switched, the stored clock difference parameters of the hot standby clock are directly and autonomously called to replace the clock difference parameters of the master clock as satellite clock difference data, the satellite clock difference data after switching is compensated, and the frequency drift rate of the satellite clock difference data is corrected; The method for calculating the clock difference parameters of the master clock by using a satellite-ground two-way comparison method combined with satellite-ground two-way ranging observation data comprises the following steps: A ground control system transmits an uplink signal with a ground reference atomic clock as a reference, and establishes an uplink ranging link with a satellite, the satellite takes a master clock of a satellite-borne atomic clock as a reference, and simultaneously transmits a downlink signal to establish a downlink ranging link with the ground control system, the satellite measures an uplink pseudo-range value between the satellite and the ground, and the ground control system measures a downlink pseudo-range value between the satellite and the ground; The uplink pseudo-range value is returned to the ground control system through telemetry, and the ground control system calculates the clock difference of the master clock relative to the ground reference atomic clock within a sampling period according to the downlink pseudo-range value and the uplink pseudo-range value; The uplink pseudo-range value and the clock difference of the hot standby clock relative to the master clock are both transmitted to the ground in real time through a satellite-ground measurement and control channel, and are collected to the ground control system for data processing to obtain the clock difference of the master clock relative to the ground reference atomic clock and the clock difference of the hot standby clock relative to the ground reference atomic clock; The method for obtaining the clock difference parameters of the hot standby clock relative to the master clock through the engineering telemetry data broadcast by the in-orbit navigation satellite comprises the following steps: A satellite time-frequency processing system measures and records the clock difference of the hot standby clock relative to the master clock in real time; The clock difference of the hot standby clock relative to the master clock measured and recorded by the satellite time-frequency processing system is the difference between the phase of the hot standby clock output signal and the phase of the master clock output signal; The phase difference between the hot standby clock output signal and the master clock output signal is measured by a phase detector of a satellite-borne time-frequency processing system, and is the clock difference of the hot standby clock relative to the master clock; The method for calculating the clock difference parameters of the hot standby clock by using a satellite onboard master-slave atomic clock phase comparison method according to the clock difference parameters of the master clock and the engineering telemetry data comprises the following steps: The clock difference of the hot backup clock relative to the master clock is returned to the ground operation and control system through telemetry, and the ground operation and control system obtains the clock difference of the hot backup clock relative to the ground reference atomic clock according to the clock difference of the master clock relative to the ground reference atomic clock and the clock difference of the hot backup clock relative to the master clock.

2. The navigation satellite on-orbit master-slave clock frequency drift rate optimal transfer method according to claim 1, characterized in that, The multiple master clock difference parameters calculated by the star-ground two-way comparison method in combination with the star-ground two-way ranging observation data further include: The satellite measures the uplink pseudo-range value between the satellite and the ground as the sum of the microwave propagation time delay between the satellite and the ground and the clock difference of the master clock relative to the ground reference atomic clock; The ground operation and control system measures the downlink pseudo-range value between the satellite and the ground as the difference between the microwave propagation time delay between the satellite and the ground and the clock difference of the master clock relative to the ground reference atomic clock; The satellite and the ground microwave propagation time delay contained in the uplink pseudo-range value measured in the same sampling period is equal to the satellite and the ground microwave propagation time delay contained in the downlink pseudo-range value.

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