Satellite clock frequency difference and phase difference determination method, system, equipment, medium and product

Abstract

The invention relates to a satellite clock frequency difference and phase difference determination method, system and device, a medium and a product, and the method comprises the steps: carrying out the bidirectional comparison clock difference measurement of adjacent satellites when a time-frequency reference reported by an operation control center is received, and obtaining the initial frequency difference and initial phase difference of a satellite clock; performing volume Kalman filtering prediction on the initial phase difference according to the current time frequency information and a clock phase difference value at a previous moment of the current moment to obtain a phase difference prediction value; according to a preset period, taking a frequency difference average value measured by the neighbor satellites of the adjacent satellites as a target frequency difference of a satellite clock, and taking a phase difference average value measured by the adjacent satellites as an updated initial phase difference; and processing the phase difference predicted value, the target frequency difference and the updated initial phase difference by adopting a volume Kalman filtering strategy to obtain the target phase difference of the satellite clock, so that an accurate adjustment basis is provided for calibration of the satellite clock, and the clock synchronization precision is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of satellite communication, and in particular to a satellite clock frequency difference and phase difference determination method, system, device, medium and product. BACKGROUND

[0002] Very long baseline interferometry (VLBI) is a high-precision astronomical observation technology. By simultaneously observing celestial bodies from multiple observation stations that are far apart, data is comprehensively processed to achieve high-precision measurement. In recent years, VLBI technology has been extended from the ground to space platforms (such as satellite constellations) to break through the diameter limit of the Earth, improve measurement accuracy, and avoid the effects of atmospheric fading and rain fading. Inter-satellite laser links are used for satellite communication due to their high speed and high security, making high-precision inter-satellite time synchronization possible.

[0003] The inter-satellite time and frequency transfer algorithm commonly used in related technologies adopts a centralized scheme, taking the clock of a master satellite (a satellite that can obtain a time and frequency reference from a ground control center through a feeder link) as a reference clock, considering the satellite constellation as a multi-hop network, and achieving time synchronization layer by layer. However, such a centralized scheme is prone to cumulative errors between layers, making it difficult to meet the requirements for time and frequency synchronization and phase synchronization. SUMMARY

[0004] Therefore, it is necessary to provide a satellite clock frequency difference and phase difference determination method, system, device, medium and product to solve the above technical problems.

[0005] In a first aspect, the present application provides a satellite clock frequency difference and phase difference determination method, which comprises:

[0006] Upon receiving the time and frequency reference reported by the control center, bidirectional comparative clock difference measurement is performed on adjacent satellites to obtain initial frequency difference and initial phase difference of the satellite clock;

[0007] According to the current time and frequency information and the clock phase difference value at the previous time of the current time, the initial phase difference is subjected to cubature Kalman filter prediction to obtain a phase difference prediction value; the current time and frequency information includes the initial frequency difference, the initial phase difference and the current time;

[0008] According to a preset period, the average of the frequency difference measured by the neighbor satellites of the adjacent satellites is taken as the target frequency difference of the satellite clock, and the average of the phase difference measured by the adjacent satellites is taken as the updated initial phase difference;

[0009] The phase difference prediction value, the target frequency difference and the updated initial phase difference are processed using a cubature Kalman filter strategy to obtain a target phase difference of the satellite clock.

[0010] In one of the embodiments, according to the current time-frequency information and the clock phase difference value of the previous time of the current time, the initial phase difference is subjected to cubature Kalman filtering prediction to obtain a phase difference prediction value, including:

[0011] Based on the preset minimum variance of the phase difference and the operation value of the clock phase difference value of the previous time of the current time, a prediction cubature point required by the cubature Kalman filtering is determined;

[0012] According to the prediction cubature point and the preset clock phase difference model, the phase difference prediction value is obtained.

[0013] In one of the embodiments, the determination process of the minimum variance includes:

[0014] The historical phase difference data of the satellite clock in a first historical time period is obtained;

[0015] According to different division rules, the historical phase difference data is divided into a plurality of different processing data; each processing data includes prediction data and prediction data; the sum of the time length of the prediction data and the time length of the prediction data is the time length corresponding to the first historical time period;

[0016] For each processing data, the historical phase difference data at each time in the prediction data of the processing data is fitted to obtain a phase difference prediction model, the prediction data of the processing data is predicted according to the phase difference prediction model to obtain a prediction value corresponding to the prediction data, and based on the prediction data and the prediction value, a prediction variance is determined;

[0017] The minimum value of the prediction variances corresponding to the plurality of different processing data is determined as the minimum variance.

[0018] In one of the embodiments, the cubature Kalman filtering strategy is adopted to process the phase difference prediction value, the target frequency difference and the updated initial phase difference to obtain a target phase difference of the satellite clock, including:

[0019] Based on the phase difference prediction value and a preset prediction formula, a variance prediction value of the phase difference is determined;

[0020] Based on the phase difference prediction value and the variance prediction value of the phase difference, a measurement cubature point is determined;

[0021] According to an observation equation, a prediction value of the phase difference observation value corresponding to the measurement cubature point is determined; the observation equation is determined according to the frequency difference average value and the phase difference average value;

[0022] According to the average value of the prediction value of the phase difference observation value corresponding to the measurement cubature point, an updated phase difference prediction value is determined;

[0023] Based on the updated phase difference prediction value, a new gain is determined, and based on the new gain and the phase difference prediction value, a target phase difference of the satellite clock is determined.

[0024] In one of the embodiments, the innovation gain is determined based on the updated phase difference prediction value, including:

[0025] The innovation variance is determined based on the updated phase difference prediction value.

[0026] The cross-covariance between the measurement value and the prediction value of the phase difference is determined according to the updated phase difference prediction value, the prediction value of the phase difference observation value corresponding to the measurement volume point, and the phase difference prediction value.

[0027] The innovation gain is determined according to the product of the cross-covariance and the innovation variance.

[0028] In one of the embodiments, the clock phase difference value at the previous moment of the current moment is determined according to a preset clock model, and the construction process of the clock model includes:

[0029] The historical initial frequency difference, the historical initial phase difference and the clock noise of the satellite clock at different moments in a second historical time period are obtained.

[0030] The relationship between the phase difference sequence of the satellite clock and the time is fitted by using the polynomial model, the historical initial frequency difference, the historical initial phase difference and the clock noise, to obtain the clock model.

[0031] In a second aspect, the application further provides a satellite clock frequency difference and phase difference determination system, which comprises:

[0032] An initial data acquisition module is configured to perform bidirectional comparison clock difference measurement on adjacent satellites when receiving the time-frequency reference reported by the operation and control center, to obtain the initial frequency difference and the initial phase difference of the satellite clock.

[0033] A clock phase difference prediction module is configured to perform cubature Kalman filter prediction on the initial phase difference according to the current time-frequency information and the clock phase difference value at the previous moment of the current moment, to obtain the phase difference prediction value; the current time-frequency information includes the initial frequency difference, the initial phase difference and the current moment.

[0034] A frequency difference and phase difference determination module is configured to take the frequency difference average value measured by the adjacent satellite of the adjacent satellite as the target frequency difference of the satellite clock and take the phase difference average value measured by the adjacent satellite as the updated initial phase difference according to a preset period; and perform processing on the phase difference prediction value, the target frequency difference and the updated initial phase difference by using the cubature Kalman filter strategy, to obtain the target phase difference of the satellite clock.

[0035] In a third aspect, the application further provides a computer device, which comprises a memory and a processor, the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0036] When the time-frequency reference reported by the operation control center is received, a two-way comparison clock difference measurement is performed on the adjacent satellites to obtain an initial frequency difference and an initial phase difference of the satellite clock;

[0037] According to the current time-frequency information and a clock phase difference value at a previous moment of the current moment, the initial phase difference is subjected to a cubature Kalman filtering prediction to obtain a phase difference prediction value; the current time-frequency information includes the initial frequency difference, the initial phase difference and the current moment;

[0038] According to a preset period, an average of the frequency differences measured by the neighbor satellites of the adjacent satellites is taken as a target frequency difference of the satellite clock, and an average of the phase differences measured by the adjacent satellites is taken as an updated initial phase difference;

[0039] The phase difference prediction value, the target frequency difference and the updated initial phase difference are processed by using a cubature Kalman filtering strategy to obtain a target phase difference of the satellite clock.

[0040] In a fourth aspect, the present application further provides a computer readable storage medium, which has a computer program stored thereon, and the computer program is executed by a processor to implement the following steps:

[0041] When the time-frequency reference reported by the operation control center is received, a two-way comparison clock difference measurement is performed on the adjacent satellites to obtain an initial frequency difference and an initial phase difference of the satellite clock;

[0042] According to the current time-frequency information and a clock phase difference value at a previous moment of the current moment, the initial phase difference is subjected to a cubature Kalman filtering prediction to obtain a phase difference prediction value; the current time-frequency information includes the initial frequency difference, the initial phase difference and the current moment;

[0043] According to a preset period, an average of the frequency differences measured by the neighbor satellites of the adjacent satellites is taken as a target frequency difference of the satellite clock, and an average of the phase differences measured by the adjacent satellites is taken as an updated initial phase difference;

[0044] The phase difference prediction value, the target frequency difference and the updated initial phase difference are processed by using a cubature Kalman filtering strategy to obtain a target phase difference of the satellite clock.

[0045] In a fifth aspect, the present application further provides a computer program product, which includes a computer program, and the computer program is executed by a processor to implement the following steps:

[0046] When the time-frequency reference reported by the operation control center is received, a two-way comparison clock difference measurement is performed on the adjacent satellites to obtain an initial frequency difference and an initial phase difference of the satellite clock;

[0047] According to the current time-frequency information and a clock phase difference value at a previous moment of the current moment, the initial phase difference is subjected to a cubature Kalman filtering prediction to obtain a phase difference prediction value; the current time-frequency information includes the initial frequency difference, the initial phase difference and the current moment;

[0048] According to a preset period, the average of the frequency difference measured by the neighbor satellite of the adjacent satellite is taken as the target frequency difference of the satellite clock, and the average of the phase difference measured by the adjacent satellite is taken as the updated initial phase difference;

[0049] The target phase difference of the satellite clock is obtained by processing the phase difference prediction value, the target frequency difference and the updated initial phase difference using the cubature Kalman filtering strategy.

[0050] The satellite clock frequency difference and phase difference determination method, system, device, medium and product provided by the above embodiments are used for, for each satellite, when the time-frequency reference reported by the operation and control center is received, first performing bidirectional comparison clock difference measurement on the adjacent satellite to obtain the initial frequency difference and the initial phase difference of the satellite clock, which helps to provide basic data for subsequent clock calibration; then performing cubature Kalman filtering prediction on the initial phase difference according to the current time-frequency information and the clock phase difference value at the time point one hour before the current time point to obtain the phase difference prediction value, which helps to estimate the phase difference change of the satellite clock in advance and provides a reference for subsequent clock calibration, thereby improving the timeliness and accuracy of clock synchronization, wherein the current time-frequency information includes the initial frequency difference, the initial phase difference and the current time point; then according to a preset period, the average of the frequency difference measured by the neighbor satellite of the adjacent satellite is taken as the target frequency difference of the satellite clock, and the average of the phase difference measured by the adjacent satellite is taken as the updated initial phase difference, which helps to improve the accuracy of the frequency difference and phase difference measurement; finally, the target phase difference of the satellite clock is obtained by processing the phase difference prediction value, the target frequency difference and the updated initial phase difference using the cubature Kalman filtering strategy, which helps to provide accurate adjustment basis for the calibration of the satellite clock, thereby further improving the accuracy of clock synchronization. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 An application environment diagram of the satellite clock frequency difference and phase difference determination method provided by some embodiments of the present application is provided;

[0052] Figure 2 A flowchart of the satellite clock frequency difference and phase difference determination method provided by some embodiments of the present application is provided;

[0053] Figure 3 A principle diagram of bidirectional comparison clock difference measurement provided by some embodiments of the present application is provided;

[0054] Figure 4 A flowchart of obtaining the phase difference prediction value provided by some embodiments of the present application is provided;

[0055] Figure 5 A flowchart of determining the minimum variance provided by some embodiments of the present application is provided;

[0056] Figure 6 A flowchart of determining the target phase difference provided by some embodiments of the present application is provided;

[0057] Figure 7 A flowchart for determining innovation gain provided for some embodiments of this application;

[0058] Figure 8 Flowcharts for constructing clock models provided for some embodiments of this application;

[0059] Figure 9 This application provides a structural block diagram of a satellite clock frequency difference and phase difference determination system according to some embodiments;

[0060] Figure 10 This is a schematic diagram of the structure of a satellite clock frequency difference and phase difference determination system provided in a detailed embodiment of this application;

[0061] Figure 11 This is an internal structural diagram of a computer device provided in some embodiments of this application. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0063] The satellite clock frequency difference and phase difference determination method provided in this application embodiment can be applied to, for example, Figure 1 The illustrated ring satellite network includes a master satellite and multiple sequentially connected slave satellites. Adjacent satellites communicate bidirectionally via laser links. Specifically, satellites can periodically send clock signals to neighboring satellites via laser links to measure clock differences, thereby achieving time-frequency transmission. Furthermore, each satellite has a controller that executes the satellite clock frequency and phase difference determination method provided in this embodiment to accurately determine the clock frequency and phase differences between each slave satellite and the master satellite. This helps each slave satellite calibrate its own atomic clock output time and signal transmission frequency, ensuring time-frequency consistency among all satellites.

[0064] In one embodiment, such as Figure 2 As shown, this method is applied to Figure 1 The method will be illustrated using a satellite processor as an example. In this embodiment, the method includes the following steps:

[0065] Step 202: Upon receiving the time and frequency reference reported by the Operations Control Center, perform bidirectional comparison clock difference measurement on adjacent satellites to obtain the initial frequency difference and initial phase difference of the satellite clocks.

[0066] Among them, the operation control center is the satellite operation control center, which is the core institution for managing and controlling the satellite, responsible for collecting various data of the satellite, sending instructions to the satellite, monitoring the running state of the satellite, and performing orbit calculation, attitude control and other operations. In the process of determining the satellite clock frequency difference and phase difference, the operation control center provides time and frequency reference, and provides standard reference for the calibration of satellite clock. The time and frequency reference is a time and frequency standard with high accuracy and high stability, usually based on high-precision devices such as atomic clocks, and is the basis for the normal operation of the entire satellite system. The role of time and frequency reference is to provide a unified standard for time and frequency measurement, ensuring that the clocks of each satellite in the satellite system can be accurately synchronized.

[0067] In the satellite network, adjacent satellites refer to satellites that are close in space position to the current satellite and can communicate and exchange data. Adjacent satellites can measure clock difference and exchange information to achieve clock synchronization and calibration. Two-way comparative clock difference measurement is a method of measuring clock difference by transmitting signals between two satellites. Specifically, two satellites send signals with time stamps to each other, and then calculate the clock difference according to the sending and receiving time of the signals, the purpose of which is to accurately measure the clock difference between adjacent satellites and obtain the initial frequency difference and initial phase difference of the satellite clock, providing basic data for subsequent clock calibration. Referring to Figure 3 , the clock difference measurement result obtained by two-way comparative clock difference measurement can be expressed as: , wherein, and are the signal sending times of clock and clock , and represent the signal receiving times of clock and clock , and represent the signal transmission times from reference clock to target clock and from clock to clock , and represent the sending delays of and , and represent the receiving delays of and .

[0068] In the process of two-way comparison of clock difference, the local clock signal is modulated in laser by optical modulator and sent, and the time-frequency information in the signal is obtained by local processing unit after demodulation by optical demodulator at the receiving end, so the transmission and receiving time delay 、 、 、 The time delay caused by optical modulation and demodulation process is included in the delay caused by the equipment, and the two parts of time delay can be obtained by initial calibration. and respectively represent the signal transmission time from the reference clock to the target clock and from the clock to the clock , and the two parts can be offset when the two-way channel is completely symmetrical, but in this scenario, since the satellites are in relative motion, in order to obtain high-precision time synchronization, the satellite position information at the time of transmitting the clock information needs to be transmitted at the same time, which can be obtained by ephemeris, thereby modeling and as follows:

[0069] ;

[0070] ;

[0071] wherein, and are the signal transmission time of the reference clock and the target clock respectively, 、 represent the position vector of the satellite at the signal transmission and receiving time through ephemeris, 、 represent the position vector of the satellite at the signal transmission and receiving time through ephemeris, represents the vector length.

[0072] The initial frequency difference of the satellite clock refers to the initial difference of the clock frequency between adjacent satellites after two-way comparison of clock difference. The initial frequency difference reflects the inconsistency of the clock frequency of two satellites. The initial phase difference of the satellite clock refers to the initial difference of the clock phase between adjacent satellites after two-way comparison of clock difference. The initial phase difference reflects the time offset of two satellite clocks at a certain time.

[0073] Optionally, the main satellite receives the time and frequency reference reported by the operation control center, and performs two-way comparison of clock difference with the adjacent satellites, records the sending and receiving time of the signal, calculates the clock difference according to the time difference, and obtains the initial frequency difference and initial phase difference of the satellite clock of the adjacent satellite; the satellite obtaining the initial frequency difference and initial phase difference performs two-way comparison of clock difference with its neighbor, so that each satellite in the ring satellite network can obtain the initial frequency difference and initial phase difference.

[0074] Specifically, step A: the main satellite in the satellite network is recorded as No. 0, and the remaining satellites are recorded as 1~N, where N is the total number of satellites in the satellite network. The clock of the main satellite corrected by the ground control center is taken as the reference system, that is, the clock frequency offset , phase deviation of the main satellite is 0. The clock frequency offset and phase offset of the remaining satellites are recorded as , , respectively according to their numbers. The two-way comparison of clock difference measurement results of a certain satellite and the main satellite are recorded as , , , and the interval time between the two measurements is , so that the initial frequency difference and the initial phase difference of the satellite clock are obtained:

[0075] ;

[0076] ;

[0077] In the formula, , the clock frequency of the satellite at this moment is represented.

[0078] Further, step B: the satellite obtaining the initial frequency difference and initial phase offset is recorded as satellite , and a certain neighbor satellite of the satellite is recorded as satellite . The clock difference obtained by two consecutive two-way comparison of clock difference measurement between the two satellites is and , and the interval time between the two measurements is , so that the initial frequency difference of satellite is:

[0079] ;

[0080] The initial phase difference is:

[0081] ;

[0082] ​The step B is repeatedly executed until the initial frequency difference and the initial phase difference of all satellites in the ring satellite network are calculated.

[0083] In step 204, the initial phase difference is cubature Kalman filter predicted according to the current time-frequency information and the clock phase difference value of the previous moment of the current moment, to obtain a phase difference prediction value.

[0084] The current time-frequency information refers to the information related to the clock at the current moment, including the initial frequency difference, the initial phase difference and the current moment. The current time-frequency information is used to provide input data for the cubature Kalman filter prediction, so as to predict the phase difference of the satellite clock. The clock phase difference value of the previous moment of the current moment refers to the phase difference value of the satellite clock obtained by measurement or calculation at the previous moment of the current moment. In the cubature Kalman filter prediction, the clock phase difference value of the previous moment of the current moment can be used as historical information to update the prediction model, so as to improve the accuracy of the prediction.

[0085] The cubature Kalman filter prediction of the initial phase difference is to use the cubature Kalman filter algorithm to predict the phase difference of the satellite clock according to the current time-frequency information and the clock phase difference value of the previous moment, to obtain a phase difference prediction value. The phase difference prediction value is an estimated value of the phase difference of the satellite clock at a future moment obtained by the cubature Kalman filter prediction. The phase difference prediction value can provide a reference for subsequent clock calibration, so as to help the satellite to adjust the clock in advance, thereby reducing the clock error.

[0086] Optionally, a cubature Kalman filter model can be established according to the current time-frequency information (the initial frequency difference, the initial phase difference and the current moment) and the clock phase difference value of the previous moment of the current moment, to predict the initial phase difference and obtain a phase difference prediction value.

[0087] It can be understood that the phase difference of the satellite clock will change with time, and the traditional measurement method can only obtain the phase difference value at the current moment, and cannot predict the future phase difference. In step 204, the initial phase difference is predicted by using the cubature Kalman filter algorithm, which can estimate the phase difference change of the satellite clock in advance, so as to provide a reference for subsequent clock calibration and improve the timeliness and accuracy of clock synchronization.

[0088] In step 206, the frequency difference average value measured by the neighbor satellite of the adjacent satellite is taken as the target frequency difference of the satellite clock, and the phase difference average value measured by the adjacent satellite is taken as the updated initial phase difference, according to a preset period.

[0089] The preset period refers to a time interval for updating the frequency difference and the phase difference in the satellite clock calibration process. The preset period can be determined according to requirements of the ring satellite network, running characteristics of the satellite, and different accuracy requirements of the system on the clock, and the like. For example, if the system has a high accuracy requirement on clock synchronization, the preset period can be set to be short; if the running state of the satellite is stable, the preset period can be appropriately lengthened.

[0090] Optionally, frequency difference and phase difference data measured by the neighbor satellites of the adjacent satellite are collected according to the preset period, and a frequency difference average value and a phase difference average value are respectively calculated, the frequency difference average value is taken as the target frequency difference of the satellite clock, and the phase difference average value is taken as the updated initial phase difference.

[0091] It can be understood that, in the running process of the satellite, the measurement data can have errors. By calculating the frequency difference average value and the phase difference average value, the measurement errors can be reduced, and thus the accuracy of the frequency difference and phase difference measurement can be improved. Meanwhile, the target frequency difference and the initial phase difference are updated regularly, so that the satellite clock can timely adapt to clock changes, and thus the stability of clock synchronization can be improved.

[0092] Step 208: A cubature Kalman filtering strategy is adopted to process the phase difference prediction value, the target frequency difference, and the updated initial phase difference, to obtain a target phase difference of the satellite clock.

[0093] The target phase difference of the satellite clock is the final target of the satellite clock calibration.

[0094] Optionally, the cubature Kalman filtering strategy is adopted to take the phase difference prediction value, the target frequency difference, and the updated initial phase difference as inputs, and the inputs are processed through a filtering algorithm to obtain the target phase difference of the satellite clock.

[0095] It can be understood that, the cubature Kalman filtering algorithm can comprehensively consider multiple factors to accurately estimate the phase difference of the satellite clock. By processing the phase difference prediction value, the target frequency difference, and the updated initial phase difference to obtain the final target phase difference, accurate adjustment basis can be provided for the calibration of the satellite clock, and thus the accuracy of clock synchronization can be further improved.

[0096] The above satellite clock frequency difference and phase difference determination method can accurately measure and predict the frequency difference and the phase difference of the satellite clock by means of bidirectional comparison clock difference measurement, cubature Kalman filtering prediction, and regular updating of the frequency difference and the phase difference, to provide accurate basis for the calibration of the satellite clock, and thus the accuracy of clock synchronization of the entire satellite system can be improved. In addition, by calculating the frequency difference average value and the phase difference average value, the influence of measurement errors can be reduced, and thus the accuracy of the frequency difference and phase difference measurement can be improved.

[0097] In one embodiment, as shown in FIG. 1, a satellite clock calibration system includes a satellite clock 100, a satellite clock calibration device 200, and a satellite clock calibration method 300. Figure 4As shown, according to the current time-frequency information and the clock phase difference value of the previous moment of the current moment, the initial phase difference is subjected to cubature Kalman filtering prediction to obtain a phase difference prediction value, including:

[0098] In step 402, based on the preset minimum variance of the phase difference and the operation value of the clock phase difference value of the previous moment of the current moment, a prediction cubature point required by the cubature Kalman filtering is determined.

[0099] The prediction cubature point is a point determined based on the preset minimum estimation variance of the phase difference and the clock phase difference value of the previous moment of the current moment, and there are usually two prediction cubature points. The cubature point is a key element in the cubature Kalman filtering prediction algorithm, and the clock phase difference can be sampled through the two prediction cubature points. The probability distribution of the system state is approximated using these sampling points, and then the prediction of the clock phase difference is realized to overcome the problem caused by the non-Gaussian nature of the clock noise and improve the accuracy of the prediction.

[0100] Optionally, first, the minimum estimation variance of the phase difference is obtained according to the system pre-setting or through the previous data statistical analysis , and the clock phase difference value of the previous moment of the current moment is obtained ; then, two prediction cubature points are generated according to the following formula and :

[0101] ;

[0102] .

[0103] In step 404, the phase difference prediction value is obtained according to the prediction cubature point and the preset clock phase difference model.

[0104] The preset clock phase difference model is a mathematical model describing the change rule of the clock phase difference, and its function is to calculate the corresponding phase difference prediction value according to the value of the prediction cubature point.

[0105] Optionally, the two prediction cubature points obtained above are substituted into the preset clock phase difference model , and and are calculated; finally, the phase difference prediction value is calculated according to the formula 2.

[0106] It can be understood that in the actual satellite clock system, the clock noise often has a non-Gaussian nature, and the traditional filtering method may not be able to accurately process such noise. The cubature filtering based on the cubature point (Caubature) transformation can better adapt to the non-Gaussian noise environment, and by generating the cubature point and using the preset clock phase difference model for phase difference prediction, the phase difference prediction accuracy under the non-Gaussian noise can be effectively improved.

[0107] In one embodiment, as shown in FIG. 4, the determination process of the minimum variance comprises: Figure 5

[0108] At step 502, historical difference data of the satellite clock in a first historical time period is obtained.

[0109] The first historical time period is a pre-selected time interval in the past, used for collecting and analyzing relevant data of the satellite clock. The selection of the first time period needs to consider the characteristics of the satellite system, the regularity of clock change, and the effectiveness of data, etc. factors, and usually needs to be long enough to contain enough clock change information, and cannot be too long to cause the data to be too old and lose reference value. The historical difference data is the difference record between the satellite clock and the standard clock in the first historical time period. The historical difference data reflects the time deviation of the satellite clock in the past period of time, and is the basis for subsequent analysis and modeling.

[0110] Optionally, the difference record between the satellite clock and the standard clock in the first historical time period can be extracted from the data storage device or database of the satellite system. These difference records can be collected and stored in real time by high-precision clock measurement equipment.

[0111] At step 504, the historical difference data is divided into a plurality of different processing data according to different division rules; each processing data includes prediction data and prediction data.

[0112] The sum of the time length of the prediction data and the time length of the prediction data is the time length corresponding to the first historical time period. Different division rules refer to rules for dividing the historical difference data in the first historical time period into prediction data and prediction data in different ways. For example, it can be divided according to a fixed time ratio, such as the first 70% of the data as prediction data and the last 30% of the data as prediction data.

[0113] Optionally, a fixed time ratio division rule can be used to divide the historical difference data into prediction data and prediction data according to a set time ratio.

[0114] At step 506, for each processing data, the historical difference data at each time in the prediction data of the processing data is fitted to obtain a difference prediction model, the prediction data of the processing data is predicted according to the difference prediction model, the prediction value corresponding to the prediction data is obtained, and the prediction variance is determined based on the prediction data and the prediction value.

[0115] ​The phase difference prediction model is a mathematical model obtained by fitting the historical phase difference data at each time in the prediction data of the processing data. The phase difference prediction model is used to describe the variation law of the satellite clock phase difference with time, and can predict the future phase difference according to the known historical data. The phase difference prediction model can be a linear model, a polynomial model, a time series model, etc. The specific model selection depends on the characteristics of the historical phase difference data.

[0116] Optionally, for each kind of processing data, if the data presents a linear trend, a linear regression method can be used for fitting; if the data has periodicity, a Fourier series method or the like can be used for fitting. After obtaining the phase difference prediction model, the time point corresponding to the prediction data is substituted into the model to obtain the predicted value of the prediction data. Then, the error sum of squares between the actual value and the predicted value of the prediction data is calculated, and then divided by the number of prediction data to obtain the prediction variance.

[0117] Step 508, determining the minimum value in the prediction variances corresponding to the plurality of different processing data as the minimum variance.

[0118] Optionally, the prediction variances corresponding to the plurality of different processing data can be compared to find the minimum value, and the minimum value is determined as the minimum variance.

[0119] In this embodiment, by using a plurality of division rules and fitting methods, the historical phase difference data is analyzed and modeled from different angles, which can more comprehensively capture the variation law of the satellite clock phase difference, so as to select the model and division method with the minimum prediction error, and improve the accuracy of phase difference prediction. In addition, the determined minimum variance can be used as an important parameter of the cubature Kalman filtering algorithm and the like, to optimize the filtering process and improve the filtering effect, and thus improve the synchronization accuracy of the satellite clock.

[0120] In one embodiment, as shown in FIG. 6, a cubature Kalman filtering strategy is used to process the phase difference prediction value, the target frequency difference and the updated initial phase difference to obtain the target phase difference of the satellite clock, including: Figure 6

[0121] Step 602, determining a variance prediction value of the phase difference based on the phase difference prediction value and a preset prediction formula.

[0122] The variance prediction value of the phase difference reflects the uncertainty degree of the phase difference prediction value, and can measure the possible deviation degree between the prediction result and the true value, which is an important parameter for subsequent calculation of the measurement cubature point and the innovation variance.

[0123] Optionally, the variance prediction value of the phase difference can be calculated based on the following preset prediction formula :

[0124] .​

[0125] At step 604, the measurement volume point is determined based on the phase difference prediction value and the variance prediction value of the phase difference.

[0126] The measurement volume point can sample the system state and more comprehensively describe the probability distribution of the phase difference, thereby improving the accuracy of filtering in a non-Gaussian noise environment.

[0127] Optionally, the measurement volume point can be determined according to the following formula and :

[0128] ; .

[0129] At step 606, the prediction value of the phase difference observation value corresponding to the measurement volume point is determined according to the observation equation.

[0130] The observation equation is determined according to the frequency difference average value and the phase difference average value, and is used to describe the relationship between the clock difference measurement results between satellites and the state variables such as the phase difference and the frequency difference. The observation equation can link the state variables (phase difference, frequency difference, etc.) of the system with the observable satellite clock difference measurement values, thereby realizing the estimation and updating of the system state.

[0131] Optionally, the expression of the observation equation is as follows:

[0132] ;

[0133] According to the observation equation, the prediction values of the phase difference observation values corresponding to the two measurement volume points are calculated and :

[0134] ;

[0135] .

[0136] At step 608, the updated phase difference prediction value is determined according to the average value of the prediction values of the phase difference observation values corresponding to the measurement volume points.

[0137] The updated phase difference prediction value is a further correction of the phase difference prediction value after considering the observation information, so as to be closer to the true phase difference value.

[0138] Optionally, the updated phase difference prediction value is determined based on the following calculation formula :

[0139] .

[0140] At step 610, a new information gain is determined based on the updated phase difference prediction value, and a target phase difference of the satellite clock is determined based on the new information gain and the phase difference prediction value.

[0141] The new information gain is used to balance the weights of the prediction value and the observation value in the final estimation. By adjusting the new information gain, the filtering result can more accurately track the change of the system state.

[0142] In this embodiment, in the case that the satellite clock system has non-Gaussian noise, the system state is sampled by using the measurement volume point through the cubature Kalman filtering strategy, which can more accurately describe the probability distribution of the phase difference, thereby improving the filtering effect and the accuracy of the phase difference prediction. In addition, the clock difference measurement results between satellites are related to the system state variables through the observation equation, which can fully utilize the observation information to correct the phase difference prediction value, so that the final phase difference estimation result is closer to the true value. The introduction of the new information gain enables the filtering process to dynamically adjust the weights of the prediction value and the observation value in the final estimation according to the reliability of the two, thereby improving the adaptability and robustness of the filtering and better tracking the change of the satellite clock state.

[0143] In one embodiment, as shown in FIG. 7, based on the updated phase difference prediction value, the new information gain is determined, including: Figure 7

[0144] At step 702, a new information variance is determined based on the updated phase difference prediction value.

[0145] The new information variance can reflect the difference between the observation value and the prediction value, and measure the uncertainty of the observation information. In the filtering process, it can be used to evaluate the reliability of the observation value, and also can help to determine the weight of the observation value in the final state estimation.

[0146] Optionally, the new information variance can be determined according to the following calculation formula :

[0147] .

[0148] At step 704, a cross-covariance between the measurement value and the prediction value of the phase difference is determined according to the updated phase difference prediction value, the prediction value of the phase difference observation value corresponding to the measurement volume point, and the phase difference prediction value.

[0149] The cross-covariance between the measurement value and the prediction value of the phase difference is used to describe the correlation between the phase difference prediction value and the phase difference observation value prediction value, and also is used to measure the correlation degree between the prediction value and the observation value, so as to determine how to combine the information of the two in the state update.

[0150] Optionally, the cross-covariance between the measurement value and the prediction value of the phase difference can be determined according to the following calculation formula ​:

[0151] .

[0152] Step 706, the innovation gain is determined according to the product of the cross covariance and the innovation variance.

[0153] Optionally, the innovation gain can be determined according to the following calculation formula :

[0154] .

[0155] Finally, the target phase difference of the satellite clock obtained by the capacity product Kalman filter is :

[0156] .

[0157] In this embodiment, by accurately calculating the innovation variance and the cross covariance, a reasonable innovation gain can be obtained, so that the weights of the predicted value and the observed value can be better balanced in the filtering process, and thus the filtering result can be closer to the real satellite clock phase difference state, thereby improving the filtering precision; the filtering algorithm can also be dynamically adjusted according to different observation and prediction conditions, thereby enhancing the adaptability of the algorithm to different environments and noise conditions; in addition, the reasonable innovation gain can effectively fuse the prediction information and the observation information, so that the finally determined target phase difference of the satellite clock is more accurate, thereby helping to improve the time synchronization precision between satellites, and further helping to improve the performance of the entire satellite system and the accuracy of data processing.

[0158] In one embodiment, as shown in Figure 8 , the clock phase difference value at the previous time of the current time is determined according to a preset clock model, and the construction process of the clock model includes:

[0159] Step 802, obtaining the historical initial frequency difference, the historical initial phase difference and the clock noise of the satellite clock at different times in a second historical time period.

[0160] The second historical time period is a historical time interval selected in advance for constructing the clock model. In the second historical time period, the relevant data of the satellite clock are recorded, including the historical initial frequency difference, the historical initial phase difference and the clock noise, etc. The selection of the second historical time period needs to be determined according to the actual situation and the modeling requirement, so as to ensure that the data therein can reflect the change rule of the satellite clock, so as to construct an accurate clock model. The historical initial frequency difference refers to the difference between the initial frequency of the satellite clock and a certain reference frequency at each specific time in the second historical time period. The historical initial phase difference refers to the difference between the initial phase of the satellite clock and a certain reference phase at each specific time in the second historical time period.

[0161] Clock noise is an interference factor affecting the operation of a satellite clock, and mainly includes five mutually independent noises, i.e., white noise phase modulation, flicker noise phase modulation, white noise frequency modulation, flicker noise frequency modulation, and random walk noise frequency modulation. In different frequency bands or time periods, clock noise is dominated by one of the noises. The characteristics of clock noise can be expressed by clock noise frequency spectrum density and phase spectrum density Specifically,

[0162] ;

[0163] ;

[0164] In the formula, is a constant of reaction noise intensity, which can be obtained by calibration, and the calibration method is a common means in the field of clock error prediction, which will not be described here.

[0165] Optionally, a high-precision frequency measurement device can be used to measure the frequency of the satellite clock at different times in the second historical time period and compare it with the reference frequency to obtain the historical initial frequency difference at each time; a phase measurement technology can be used to measure the phase of the satellite clock at different times in the second historical time period and compare it with the reference phase to obtain the historical initial phase difference at each time; according to the expressions of clock noise frequency spectrum density and phase spectrum density, combined with relevant measurement data and calibration methods, the clock noise at different times in the second historical time period can be calculated. For example, the frequency distribution of the noise can be obtained by performing spectrum analysis on the satellite clock signal, and then combined with the known noise model and calibration parameters, the specific value of the clock noise can be determined.

[0166] In step 804, the relationship between the phase difference sequence of the satellite clock and time is fitted by using the polynomial model, the historical initial frequency difference, the historical initial phase difference, and the clock noise, to obtain a clock model.

[0167] In the formula, the polynomial model is a mathematical model used for modeling the clock phase difference, and the change of the satellite clock phase difference sequence over time can be expressed as:

[0168] ;

[0169] In the formula, is the historical initial phase difference; is the historical initial frequency difference; is the linear drift of the clock frequency; is the clock noise.

[0170] Optionally, the historical initial frequency difference, historical initial phase difference, and clock noise can be substituted into the polynomial model mentioned above; then, fitting methods such as least squares can be used to adjust the parameters in the model (e.g., The parameters are estimated and optimized to obtain the optimal model parameter estimates. Finally, after fitting, the specific values ​​of each parameter in the polynomial model can be determined, thus obtaining a clock model to describe the change of satellite clock phase difference sequence over time.

[0171] In this embodiment, by acquiring relevant data within the second historical time period and fitting it with a multinomial model, the variation of satellite clock phase difference over time can be captured more accurately. Furthermore, by considering multiple factors such as historical initial frequency difference, historical initial phase difference, and clock noise, the constructed clock model is more consistent with the actual situation, thereby improving the accuracy of predicting the clock phase difference value of the previous moment and the future clock phase difference.

[0172] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0173] Based on the same inventive concept, this application also provides a satellite clock frequency difference and phase difference determination system for implementing the satellite clock frequency difference and phase difference determination method described above. The solution provided by this device is similar to the implementation scheme described in the above method; therefore, the specific limitations of one or more satellite clock frequency difference and phase difference determination system embodiments provided below can be found in the limitations of the satellite clock frequency difference and phase difference determination method described above, and will not be repeated here.

[0174] In one embodiment, such as Figure 9 As shown, a satellite clock frequency difference and phase difference determination system is provided, including: an initial data acquisition module 902, a clock phase difference prediction module 904, and a frequency difference and phase difference determination module 906, wherein:

[0175] The initial data acquisition module 902 is used to perform bidirectional comparison clock difference measurement on adjacent satellites when it receives the time and frequency reference reported by the operation and control center, so as to obtain the initial frequency difference and initial phase difference of the satellite clock;

[0176] The clock phase difference prediction module 904 is configured to perform cubature Kalman filtering prediction on the initial phase difference according to the current time-frequency information and a clock phase difference value at a time point preceding the current time, to obtain a phase difference prediction value; the current time-frequency information includes an initial frequency difference, an initial phase difference and the current time;

[0177] The frequency difference and phase difference determination module 906 is configured to, according to a preset period, take an average of the frequency differences measured by the neighbor satellites of the adjacent satellites as a target frequency difference of the satellite clock, and take an average of the phase differences measured by the neighbor satellites as an updated initial phase difference; and perform processing on the phase difference prediction value, the target frequency difference and the updated initial phase difference by using a cubature Kalman filtering strategy, to obtain a target phase difference of the satellite clock.

[0178] In an embodiment, the clock phase difference prediction module 904 includes a prediction cubature point determination sub-module and a phase difference prediction value determination sub-module; the prediction cubature point determination sub-module is configured to determine a prediction cubature point required by the cubature Kalman filtering based on a preset minimum variance of the phase difference and an operation value of the clock phase difference value at a time point preceding the current time; and the phase difference prediction value determination sub-module is configured to obtain the phase difference prediction value according to the prediction cubature point and a preset clock phase difference model.

[0179] In an embodiment, the prediction cubature point determination sub-module includes a historical phase difference data acquisition unit, a historical data division unit, a prediction variance determination unit and a minimum variance determination unit; the historical phase difference data acquisition unit is configured to acquire historical phase difference data of the satellite clock in a first historical time period; the historical data division unit is configured to divide the historical phase difference data into a plurality of different processing data according to different division rules; each kind of processing data includes prediction data and prediction data; the sum of the time length of the prediction data and the time length of the prediction data is the time length corresponding to the first historical time period; the prediction variance determination unit is configured to, for each kind of processing data, fit the historical phase difference data at each time point in the prediction data of the processing data, to obtain a phase difference prediction model, predict the prediction data of the processing data according to the phase difference prediction model, obtain a prediction value corresponding to the prediction data, and determine a prediction variance based on the prediction data and the prediction value; and the minimum variance determination unit is configured to determine the minimum value of the prediction variances corresponding to the plurality of different processing data as the minimum variance.

[0180] In one embodiment, the frequency difference and phase difference determination module 906 includes a variance prediction value determination submodule, a measurement volume point determination submodule, an observation prediction value determination submodule, a phase difference prediction value update submodule, and a target phase difference determination submodule. The variance prediction value determination submodule is used to determine the variance prediction value of the phase difference based on the phase difference prediction value and a preset prediction formula. The measurement volume point determination submodule is used to determine the measurement volume point based on the phase difference prediction value and the variance prediction value of the phase difference. The observation prediction value determination submodule is used to determine the predicted value of the phase difference observation value corresponding to the measurement volume point according to the observation equation, whereby the observation equation is determined based on the average frequency difference and the average phase difference. The phase difference prediction value update submodule is used to determine the updated phase difference prediction value based on the average value of the predicted values ​​of the phase difference observation values ​​corresponding to the measurement volume point. The target phase difference determination submodule is used to determine the innovation gain based on the updated phase difference prediction value and to determine the target phase difference of the satellite clock based on the innovation gain and the phase difference prediction value.

[0181] In one embodiment, the target phase difference determination submodule includes a novelty variance determination unit, a cross-variance determination unit, and a novelty gain determination unit. The novelty variance determination unit is used to determine the novelty variance based on the updated phase difference prediction value. The cross-variance determination unit is used to determine the cross-variance between the measured value and the predicted value of the phase difference based on the updated phase difference prediction value, the predicted value of the phase difference observation value corresponding to the measurement volume point, and the phase difference prediction value. The novelty gain determination unit is used to determine the novelty gain based on the product of the cross-variance and the novelty variance.

[0182] In one embodiment, the clock phase difference prediction module 904 includes a clock model construction submodule, which is used to obtain the historical initial frequency difference, historical initial phase difference, and clock noise of the satellite clock at different times within the second historical time period; and to fit the relationship between the phase difference sequence of the satellite clock and the time change using a polynomial model, historical initial frequency difference, historical initial phase difference, and clock noise to obtain a clock model.

[0183] In a detailed embodiment, such as Figure 10 As shown, the satellite clock frequency difference and phase difference determination system in this embodiment also includes a local clock. optical modulator Laser emitter Laser receiver optical demodulator Clock difference measurement module Initial phase difference calculation module Frequency difference estimation module Phase difference measurement module Phase difference prediction module Phase difference measurement update module .

[0184] wherein the output of the local clock points to the optical modulator and the clock difference measurement module ; the local clock is used to maintain the cooperation of the whole system. The input of the optical modulator is the local clock ; the output of the optical modulator points to the laser modulator ; the optical modulator is used to modulate the clock output signal to the laser for laser transmission. The input of the laser transmitter is the optical modulator ; the output of the laser transmitter is the clock difference measurement module ; the laser transmitter is used to transmit the laser carrying the local always-on signal to other satellites through the laser link for bidirectional comparison of the clock difference. The input of the laser receiver is the laser signal transmitted through the inter-satellite laser link; the output of the laser receiver points to the optical demodulator ; the laser receiver is used to receive the laser signal transmitted through the inter-satellite laser link. The input of the optical demodulator is the laser receiver ; the output of the optical demodulator points to the clock difference measurement module ; the optical demodulator is used to demodulate the time-frequency information transmitted by other satellites from the received laser signal for bidirectional comparison of the clock difference.

[0185] The input of the clock difference measurement module is the optical demodulator and the local clock ; the output of the clock difference measurement module points to the initial frequency difference calculation module , the initial phase difference calculation module , the frequency difference estimation module , the phase difference measurement module ; the clock difference measurement module is used to measure the clock difference between the satellite and other satellites by using the bidirectional comparison measurement method, for subsequent frequency and phase error calculation. The input of the initial frequency difference calculation module is the clock difference measurement module ; the output of the initial frequency difference calculation module points to the frequency difference estimation module , the phase difference measurement module , the phase difference prediction module ; the initial frequency difference calculation module for calculating the initial frequency difference of the satellite. Initial phase difference calculation module The input of the initial phase difference calculation module is the clock difference measurement module ; the output of the initial phase difference calculation module points to the frequency difference estimation module , the phase difference measurement module , the phase difference prediction module ; the initial phase difference calculation module is used for the initial phase difference of the satellite. The input of the frequency difference estimation module is the clock difference measurement module , the initial frequency difference calculation module , the initial phase difference calculation module . The output of the frequency difference estimation module is the clock frequency difference; the frequency difference estimation module is used for obtaining the clock frequency difference by using the bi-directional contrast measurement result of the neighbor satellite. The input of the phase difference measurement module is the clock difference measurement module , the initial frequency difference calculation module , the initial phase difference calculation module ; the output of the phase difference measurement module is the phase difference measurement update module ; the phase difference measurement module is used for obtaining the average value of the satellite clock difference measurement according to the clock difference result obtained by the bi-directional contrast measurement of the satellite and the neighbor satellite.

[0186] The input of the phase difference prediction module is the initial frequency difference calculation module , the initial phase difference calculation module , the frequency difference estimation module , the phase difference measurement module ; the output of the phase difference prediction module is the phase difference measurement update module ; the phase difference prediction module is used for performing phase difference prediction according to the initial frequency difference of the satellite, the initial phase difference, and the clock frequency difference and the phase difference in a period of time, and calculating the prediction variance. The input of the phase difference measurement update module is the phase difference measurement module , the phase difference prediction module ; the output of the phase difference measurement update module updates the clock phase difference; the phase difference measurement update module is used for updating the clock phase difference according to the phase difference prediction result, the prediction variance, and the phase difference measurement result according to the cubature Kalman filter.

[0187] The modules in the satellite clock frequency difference and phase difference determination system can be implemented by software, hardware, or a combination thereof. The modules can be embedded in a processor in a computer device or independent of the processor, or stored in a memory in the computer device in a software form, so that the processor can execute the operations of the modules.

[0188] In an embodiment, a computer device is provided, which can be a control component inside a satellite. The internal structure of the computer device can be as shown in FIG. 1. Figure 11 The computer device includes a processor, a memory, a communication interface, an input device, and the like connected by a system bus. The processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for running the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is configured to perform wired or wireless communication with an external terminal. The wireless communication can be achieved by WIFI, mobile cellular network, NFC (Near Field Communication), or other technologies. The computer program is executed by the processor to implement a satellite clock frequency difference and phase difference determination method.

[0189] Those skilled in the art can understand that Figure 11 The structure shown in FIG. 1 is only a block diagram of part of the structure related to the scheme of the present application, and does not limit the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0190] In an embodiment, a computer device is provided, which includes a memory and a processor. The memory stores a computer program. The processor executes the computer program to implement the steps in the above method embodiments.

[0191] In an embodiment, a computer readable storage medium is provided, which stores a computer program. The computer program is executed by a processor to implement the steps in the above method embodiments.

[0192] In an embodiment, a computer program product is provided, which includes a computer program. The computer program is executed by a processor to implement the steps in the above method embodiments.

[0193] It should be noted that the user information (including but not limited to user device information, user personal information, and the like) and data (including but not limited to data for analysis, stored data, displayed data, and the like) involved in the present application are all information and data authorized by the user or authorized by all parties.

[0194] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0195] Any combination of the technical features of the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist, it should be considered as the scope of the present application.

[0196] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method of determining a satellite clock frequency and phase difference, characterized by, The method comprises: When receiving the time-frequency reference reported by the operation control center, performing a two-way comparison clock difference measurement on the adjacent satellites to obtain an initial frequency difference and an initial phase difference of the satellite clock; According to the current time-frequency information and the clock phase difference value at the time point before the current time point, performing a cubature Kalman filter prediction on the initial phase difference to obtain a phase difference prediction value; the current time-frequency information comprises the initial frequency difference, the initial phase difference and the current time point; According to a preset period, taking the frequency difference average value measured by the adjacent satellite of the adjacent satellite as a target frequency difference of the satellite clock, and taking the phase difference average value measured by the adjacent satellite as an updated initial phase difference; Using a cubature Kalman filter strategy, processing the phase difference prediction value, the target frequency difference and the updated initial phase difference to obtain a target phase difference of the satellite clock.

2. The method of claim 1, wherein, The cubature Kalman filter prediction of the initial phase difference according to the current time-frequency information and the clock phase difference value at the time point before the current time point to obtain a phase difference prediction value comprises: Based on the minimum variance of the phase difference and the operation value of the clock phase difference value at the time point before the current time point, a prediction cubature point required by the cubature Kalman filter is determined; According to the prediction cubature point and a preset clock phase difference model, the phase difference prediction value is obtained.

3. The method of claim 2, wherein, The determination process of the minimum variance comprises: Obtaining historical phase difference data of the satellite clock in a first historical time period; According to different division rules, the historical phase difference data is divided into a plurality of different processing data; each processing data comprises prediction data and prediction data; the sum of the time length of the prediction data and the time length of the prediction data is the time length corresponding to the first historical time period; For each processing data, the historical phase difference data at each time point in the prediction data of the processing data is fitted to obtain a phase difference prediction model, the prediction data of the processing data is predicted according to the phase difference prediction model to obtain a prediction value corresponding to the prediction data, and the prediction variance is determined based on the prediction data and the prediction value; The minimum value of the prediction variances corresponding to the plurality of different processing data is determined as the minimum variance.

4. The method of claim 1, wherein, The processing of the phase difference prediction value, the target frequency difference and the updated initial phase difference using the cubature Kalman filter strategy to obtain the target phase difference of the satellite clock comprises: Based on the phase difference prediction value and a preset prediction formula, a variance prediction value of the phase difference is determined; Based on the phase difference prediction value and the variance prediction value of the phase difference, a measurement cubature point is determined; According to an observation equation, a prediction value of a phase difference observation value corresponding to the measurement cubature point is determined; the observation equation is determined according to the frequency difference average value and the phase difference average value; According to the average value of the prediction value of the phase difference observation value corresponding to the measurement cubature point, an updated phase difference prediction value is determined; Based on the updated phase difference prediction value, a new information gain is determined, and based on the new information gain and the phase difference prediction value, the target phase difference of the satellite clock is determined.

5. The method of claim 4, wherein, The determination of the new information gain based on the updated phase difference prediction value comprises: Based on the updated phase difference prediction value, a new information variance is determined; determine, according to the updated phase difference prediction value, a prediction value of an observation value of the phase difference corresponding to the measurement volume point, and the phase difference prediction value, a cross-covariance between a measurement value and a prediction value of the phase difference; determine, according to a product of the cross-covariance and the innovation variance, the innovation gain.

6. The method of claim 1, wherein, The clock phase difference value of the previous moment of the current moment is determined according to a preset clock model, and a construction process of the clock model comprises: acquiring historical initial frequency differences, historical initial phase differences and clock noises of the satellite clock at different moments in a second historical time period; fitting a relationship of the phase difference sequence of the satellite clock changing over time by using a polynomial model, the historical initial frequency differences, the historical initial phase differences and the clock noises to obtain the clock model.

7. A system for determining satellite clock frequency and phase differences, characterized by The system comprises: an initial data acquisition module configured to, when receiving a time-frequency reference reported by an operation control center, perform bidirectional comparison clock difference measurement on adjacent satellites to obtain initial frequency differences and initial phase differences of the satellite clock; a clock phase difference prediction module configured to perform cubature Kalman filter prediction on the initial phase differences according to current time-frequency information and a clock phase difference value of a previous moment of a current moment to obtain a phase difference prediction value; the current time-frequency information comprises the initial frequency differences, the initial phase differences and the current moment; a frequency difference and phase difference determination module configured to, according to a preset period, take an average value of frequency differences measured by neighbor satellites of the adjacent satellites as a target frequency difference of the satellite clock, take an average value of phase differences measured by the adjacent satellites as an updated initial phase difference, and process the phase difference prediction value, the target frequency difference and the updated initial phase difference by using a cubature Kalman filter strategy to obtain a target phase difference of the satellite clock. 8.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-7. The processor executes the computer program to implement the steps of the method in any one of claims 1 to 6.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method in any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method in any one of claims 1 to 6.

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