GNSS (Global Navigation Satellite System) time service enhancement method and device, electronic equipment and storage medium
By acquiring and fitting historical digital quantities, the target digital quantities when GNSS navigation signal is lost are predicted, which solves the problems of local clock aging and frequency and temperature characteristics changes when GNSS navigation signal is lost, and achieves efficient timing enhancement.
Patent Information
- Application Number
- CN202510284602.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2025-07-08
AI Technical Summary
When the GNSS satellite reference signal is lost, the prior art is difficult to effectively compensate for the aging of the local clock and the changes in frequency and temperature characteristics, resulting in a decrease in timing accuracy.
By obtaining the GNSS navigation signal at historical moments, the historical digital quantity is determined, the target fitting function is obtained, and the target digital quantity at the time of the GNSS navigation signal is predicted, and the local clock is timed and enhanced based on this.
It improves the time efficiency of timing, and can maintain high-precision frequency accuracy and time synchronization capabilities when GNSS navigation signals are lost, simplifies the model establishment process and reduces considerations for other influencing factors.
Smart Images
Figure CN120275997A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of computers, and more particularly, to a method, apparatus, electronic device, and storage medium for enhancing GNSS time synchronization. Background Art
[0002] Time synchronization service is one of the three major services of the Global Navigation Satellite System (GNSS). GNSS time synchronization has the advantages of all-weather, all-day, and wide coverage, and can be widely applied to many key industries related to the national economy and people's livelihood, such as communication, power, transportation, finance, aerospace, etc.
[0003] GNSS time synchronization service is realized through GNSS time synchronization terminals. Usually, a high-precision standard space-based reference signal provided by GNSS satellite signals is used to calibrate the local clock, so that the local clock is aligned with the GNSS time reference, thereby improving the long-term frequency stability and time synchronization accuracy. However, when the GNSS satellite reference signal is lost, the local clock will be affected by factors such as its own aging and frequency-temperature characteristics, and the output frequency will drift, and the time synchronization performance will also deteriorate sharply. Therefore, how to compensate for the changes brought about by the aging and frequency-temperature characteristics of the local clock so that it still has high-precision frequency accuracy and time synchronization ability in the extreme case of GNSS satellite reference signal loss is crucial for GNSS time synchronization service. Summary of the Invention
[0004] The embodiments of the present disclosure at least provide a method, apparatus, electronic device, and storage medium for enhancing GNSS time synchronization.
[0005] In a first aspect, an embodiment of the present disclosure provides a method for enhancing GNSS time synchronization, including:
[0006] When it is detected that the GNSS navigation signal is lost, obtaining a historical digital quantity determined based on the GNSS navigation signal at a historical moment; wherein, the historical moment is a moment when the GNSS navigation signal is normal, and the historical digital quantity is used to represent the clock difference data information between the satellite clock and the local clock at the historical moment;
[0007] Fitting the historical digital quantity to obtain a target fitting function of the historical digital quantity;
[0008] Predicting a target digital quantity at the moment when the GNSS navigation signal is lost according to the target fitting function, and enhancing the time synchronization of the local clock according to the target digital quantity.
[0009] In an optional implementation, the historical digital quantity is obtained through the following method:
[0010] Receive GNSS navigation signals through a GNSS antenna, and process the GNSS navigation signals to obtain satellite navigation messages and raw observations of the GNSS navigation signals;
[0011] Solve the satellite navigation messages and the raw observations to obtain clock difference data between the satellite clock and the local clock;
[0012] Determine a digital quantity to be used according to the clock difference data, and store the digital quantity to be used to obtain the historical digital quantity.
[0013] In an optional implementation manner, the fitting the historical digital quantity to obtain a target fitting function of the historical digital quantity includes:
[0014] Construct an initial fitting function based on the historical digital quantity and the historical time corresponding to the historical digital quantity, and construct an evaluation function of the initial fitting function; wherein, the evaluation function is used to measure the quality of the initial fitting function;
[0015] Solve the evaluation function to obtain a parameter estimation value of the initial fitting function, and determine the target fitting function based on the parameter estimation value; wherein, the parameter estimation value is the value of each coefficient in the target fitting function when the evaluation function is minimized.
[0016] In an optional implementation manner, the predicting a target digital quantity at the moment when the GNSS navigation signal is lost according to the target fitting function includes:
[0017] Determine the target digital quantity based on the GNSS navigation signal loss period and the target fitting function; wherein, the signal loss period is used to indicate a target time period starting from the signal loss moment.
[0018] In an optional implementation manner, the enhancing the time synchronization of the local clock according to the target digital quantity includes:
[0019] Convert the target digital quantity and the historical digital quantity into analog quantities to obtain a first analog quantity and a second analog quantity respectively;
[0020] Adjust the output frequency of the local clock according to the first analog quantity and the second analog quantity.
[0021] In an optional implementation manner, the adjusting the output frequency of the local clock according to the first analog quantity and the second analog quantity includes:
[0022] Generate a current signal and / or a voltage signal according to the first analog quantity and the second analog quantity;
[0023] Adjust the output frequency of the local clock according to the current signal and / or voltage signal.
[0024] In a second aspect, an embodiment of the present disclosure further provides a GNSS timing enhancement device, including:
[0025] A determination module, configured to obtain historical digital quantities determined based on GNSS navigation signals at historical moments when it is detected that the GNSS navigation signal is lost; wherein, the historical moments are moments when the GNSS navigation signal is normal, and the historical digital quantities are used to represent clock difference data information between the satellite clock and the local clock at the historical moments;
[0026] A fitting module, configured to fit the historical digital quantities to obtain a target fitting function of the historical digital quantities;
[0027] A timing module, configured to predict a target digital quantity at the moment when the GNSS navigation signal is lost according to the target fitting function, and perform timing enhancement on the local clock according to the target digital quantity.
[0028] In a third aspect, an embodiment of the present disclosure further provides an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device runs, the processor communicates with the memory through the bus. When the machine-readable instructions are executed by the processor, the steps in the first aspect, or any possible implementation manner in the first aspect, are executed.
[0029] In a fourth aspect, an embodiment of the present disclosure further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is run by a processor, the steps in the first aspect, or any possible implementation manner in the first aspect, are executed.
[0030] The GNSS timing enhancement method, device, and system provided by the embodiments of the present disclosure determine historical digital quantities to obtain a target fitting function. Since the digital quantities when the GNSS navigation signal is lost still evolve according to the change law of the historical digital quantities when the GNSS navigation signal is normal. Therefore, the target digital quantity at the moment when the GNSS navigation signal is lost can be determined according to the target fitting function. Then, timing enhancement is performed on the local clock based on the target digital quantity. Moreover, the historical digital quantities are determined based on clock difference data, and the clock difference data includes all influencing factors of the local clock. Therefore, timing enhancement can be performed on the local clock only based on the determined target digital quantity, without considering other influencing factors additionally, improving the time efficiency of timing.
[0031] To make the above objects, features, and advantages of the present disclosure more obvious and understandable, the following specifically enumerates preferred embodiments and cooperates with the attached drawings for detailed description as follows. Brief Description of the Drawings
[0032] To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. The drawings herein are incorporated into the specification and constitute a part of this specification. These drawings illustrate the embodiments that conform to the present disclosure and, together with the specification, are used to explain the technical solutions of the present disclosure. It should be understood that the following drawings only illustrate some embodiments of the present disclosure and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.
[0033] Figure 1 The flowchart showing a method for enhancing GNSS timing provided by an embodiment of the present disclosure;
[0034] Figure 2 The detailed flowchart showing a method for enhancing GNSS timing provided by an embodiment of the present disclosure;
[0035] Figure 3 The schematic diagram showing a system for enhancing GNSS timing provided by an embodiment of the present disclosure;
[0036] Figure 4 The schematic diagram showing a device for enhancing GNSS timing provided by an embodiment of the present disclosure;
[0037] Figure 5 The schematic diagram showing an electronic device provided by an embodiment of the present disclosure. Detailed Embodiments
[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Usually, the components of the embodiments of the present disclosure described and illustrated in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present disclosure provided in the drawings is not intended to limit the scope of the present disclosure to be protected, but only represents the selected embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present disclosure.
[0039] It should be noted that: similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.
[0040] In this text, the term "and / or" merely describes an association relationship, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the term "at least one" in this text means any one of multiple or any combination of at least two of multiple. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set composed of A, B, and C.
[0041] It has been found through research that in existing technical solutions, there are mainly two categories of methods to enhance the GNSS timing service ability: one is to conduct long-term and extensive tests on the phase difference data of local clocks such as oven-controlled crystal oscillators or rubidium clocks under free oscillation conditions, and then perform mathematical modeling on the aging and frequency-temperature characteristics of local clocks, and then make compensation according to the model function; the other is to introduce neural network training models such as adaptive Kalman filtering, gray model, BP neural network, etc., and filter the historical clock error data accumulated when the GNSS navigation signal is normal to analyze the aging characteristics and frequency-temperature characteristics, and then achieve compensation.
[0042] Existing technical solutions all achieve the prediction and compensation of the aging and frequency-temperature characteristics of local clocks by modeling the phase difference data or clock error data of the local clocks built in the GNSS timing terminal, or by means of neural network algorithms combined with adaptive filtering, etc. Essentially, they all directly process the clock error data. Processing the clock error data has three disadvantages: First, the clock error data under normal GNSS navigation signal conditions basically remains unchanged and cannot clearly and directly represent the influence of the aging and frequency-temperature characteristics of the local clock, and further analysis and processing are required, so the implementation difficulty and complexity are increased; Second, in the case of GNSS navigation signal loss, clock error data cannot be generated, so the clock error data cannot be used. In addition, generally, long-term tests and a large amount of data need to be accumulated for modeling the aging and frequency-temperature characteristics of local clocks. When the environment where the local clock is located changes, the applicability of the established model is greatly reduced, resulting in poor compensation effects; Third, the clock error data reflects the influence of all factors, not only the influence of the aging and frequency-temperature characteristics of the local clock, but also other influences such as circuit drift, hardware delay, and temperature effect. Only modeling the aging and frequency-temperature characteristics of the local clock cannot compensate for the influence of other factors, so residuals will accumulate.
[0043] In view of the many problems of the above existing solutions, this solution proposes a new method and device for GNSS timing enhancement.
[0044] Based on the above research, the present disclosure provides a method for enhancing GNSS timing. By determining historical digital quantities to obtain a target fitting function, since the digital quantities when the GNSS navigation signal is lost still evolve according to the variation law of the historical digital quantities when the GNSS navigation signal is normal. Thus, the target digital quantity at the moment when the GNSS navigation signal is lost can be determined according to the target fitting function. Then, the local clock is enhanced in timing based on the target digital quantity. Moreover, the historical digital quantity is determined based on clock difference data, and the clock difference data includes all influencing factors of the local clock. Therefore, the local clock can be enhanced in timing only based on the determined target digital quantity without additionally considering other influencing factors, improving the time efficiency of timing.
[0045] For ease of understanding of this embodiment, first, a method for enhancing GNSS timing disclosed in the embodiments of the present disclosure is introduced in detail. The execution subject of the method for enhancing GNSS timing provided in the embodiments of the present disclosure is generally an electronic device with certain computing capabilities. In some possible implementation manners, the method for enhancing GNSS timing can be implemented by a processor calling computer-readable instructions stored in a memory.
[0046] Refer to Figure 1 As shown, it is a flowchart of a method for enhancing GNSS timing provided in the embodiments of the present disclosure. The method includes steps S101 to S103, where:
[0047] S101. In the case of detecting the loss of the GNSS navigation signal, obtain the historical digital quantity determined based on the GNSS navigation signal at a historical moment; where the historical moment is a moment when the GNSS navigation signal is normal, and the historical digital quantity is used to represent the clock difference data information between the satellite clock and the local clock at the historical moment.
[0048] In the embodiments of the present disclosure, when the GNSS antenna does not receive the GNSS navigation signal at the signal reception moment, it is determined that the GNSS navigation signal is lost.
[0049] Here, the moment before the above signal reception moment and when the GNSS navigation signal is normal can be determined as the historical moment. Among them, the GNSS navigation signals received by the GNSS antenna at several historical moments within a specified time period before the above signal reception moment can be processed to obtain the historical digital quantity corresponding to each historical moment.
[0050] S102. Fit the historical digital quantity to obtain the target fitting function of the historical digital quantity.
[0051] In the embodiments of the present disclosure, the historical digital quantity can be fitted based on a quadratic function.
[0052] Here, the parameters in the quadratic function can be determined based on minimizing the root mean square error. Among them, minimizing the root mean square error can be understood as minimizing the loss function of the quadratic function, so that the target digital quantity calculated by the determined target fitting function is more accurate.
[0053] S103. Predict the target digital quantity at the moment when the GNSS navigation signal is lost according to the target fitting function, and perform timing enhancement on the local clock according to the target digital quantity.
[0054] In the embodiments of the present disclosure, the moment when the GNSS navigation signal is lost and the fitting values of several navigation signals after the moment when the GNSS navigation signal is lost can be determined according to the target fitting function. Then, the above fitting values can be determined as the target digital quantity.
[0055] Here, the target digital quantity and the historical digital quantity can be processed to determine the output frequency of the local clock, so as to adjust the frequency of the local clock based on the output frequency, so as to achieve the purpose of enhancing the timing of the local clock.
[0056] In the embodiments of the present disclosure, first, in the case of detecting the loss of the GNSS navigation signal, obtain the historical digital quantity determined based on the GNSS navigation signal at the historical moment; where the historical moment is the moment when the GNSS navigation signal is normal, and the historical digital quantity is used to represent the clock difference data information between the satellite clock and the local clock at the historical moment; second, fit the historical digital quantity to obtain the target fitting function of the historical digital quantity; finally, predict the target digital quantity at the moment when the GNSS navigation signal is lost according to the target fitting function, and perform timing enhancement on the local clock according to the target digital quantity.
[0057] In the above implementation manner, by determining the historical digital quantity to obtain the target fitting function, because the digital quantity when the GNSS navigation signal is lost still evolves according to the change rule of the historical digital quantity when the GNSS navigation signal is normal. Therefore, the target digital quantity at the moment when the GNSS navigation signal is lost can be determined according to the target fitting function. Then, timing enhancement is performed on the local clock based on the target digital quantity. And, the historical digital quantity is determined based on the clock difference data, and the clock difference data includes all influencing factors of the local clock. Therefore, timing enhancement can be performed on the local clock only based on the determined target digital quantity, without considering other influencing factors additionally, improving the time efficiency of timing.
[0058] In an alternative embodiment, the historical digital quantity is obtained through the following processing:
[0059] First, receive the GNSS navigation signal through the GNSS antenna, and process the GNSS navigation signal to obtain the satellite navigation message and the original observation of the GNSS navigation signal.
[0060] Secondly, the satellite navigation message and the original observations are solved to obtain the clock difference data between the satellite clock and the local clock;
[0061] Finally, the digital quantity to be used is determined according to the clock difference data, and the digital quantity to be used is stored to obtain the historical digital quantity.
[0062] In the embodiment of the present disclosure, when the GNSS antenna receives the GNSS navigation signal, the GNSS navigation signal can be converted into a radio frequency signal.
[0063] After that, the GNSS antenna can send the radio frequency signal to the GNSS receiving unit. Among them, the GNSS receiving unit can perform low-noise amplification processing, power splitting processing, filtering processing, and digital intermediate frequency processing on the received radio frequency signal in sequence to obtain the satellite navigation message and the original observations of the GNSS navigation signal.
[0064] After that, the GNSS receiving unit can send the satellite navigation message and the original observations of the GNSS navigation signal to the information solving unit.
[0065] Here, the information solving unit can solve the satellite navigation message and the original observations to obtain the clock difference data between the satellite clock and the local clock.
[0066] After that, the information solving unit can send the clock difference data to the loop filtering unit. Among them, the loop filtering unit can perform digital filtering on the clock difference data and perform proportional-integral-derivative (PID) processing on the filtered clock difference data to obtain the digital quantity to be used.
[0067] Here, the digital quantity to be used d(t k ) meets the following conditions:
[0068] d(t k ) = [K1x(t k ) + K2∑ m j＝1 (x(t k )) + K3(x(t k ) - [x(t k ) - x(t (k-1) )])] + u0;
[0069] Among them, K1, K2, and K3 are state parameters when the GNSS navigation signal is normal, x(t k ) is the clock difference data at the kth moment, k ranges from 1 to m, m are the m moments before the kth moment, and u0 is a fixed value.
[0070] Here, the specific values of the state parameters can be determined through experimental debugging.
[0071] Here, when the loop filter unit normally receives the clock difference data (i.e., no loss of GNSS navigation signal is detected), the digital quantity to be used is stored.
[0072] Here, when the loop filter unit does not normally receive the clock difference data (i.e., a loss of GNSS navigation signal is detected), the digital quantity to be used in a specified time period before the moment of GNSS navigation signal loss is determined as the historical digital quantity.
[0073] In an optional embodiment, fitting is performed on the historical digital quantity to obtain the target fitting function of the historical digital quantity, which specifically includes the following steps:
[0074] Based on the historical digital quantity and the historical moment corresponding to the historical digital quantity, an initial fitting function is constructed, and an evaluation function of the initial fitting function is constructed, where the evaluation function is used to measure the quality of the initial fitting function;
[0075] The evaluation function is solved to obtain the parameter estimation value of the initial fitting function, and the target fitting function is determined based on the parameter estimation value; where the parameter estimation value is the value of each coefficient in the target fitting function when the evaluation function is minimized.
[0076] In the embodiments of the present disclosure, since the local clock is generally a crystal oscillator or a rubidium clock. Therefore, a quadratic function can be used for fitting.
[0077] Among them, the target fitting function u(t i ) of the historical digital quantity meets the following conditions:
[0078] u(t i ) = a + bt i + ct i 2 ;
[0079] Among them, a, b, and c are parameter estimation values, where t i is the i-th moment in the specified time period (i.e., the moment corresponding to the i-th historical digital quantity), the value of i ranges from 1 to N, N is the number of historical digital quantities in the specified time period, and u(t i ) is the historical digital quantity corresponding to the i-th moment in the specified time period.
[0080] Here, the determination function of the root mean square error can be determined as the loss function of the target fitting function u(t i ). Then, based on this loss function, the parameter estimation values a, b, and c are determined.
[0081] Among them, the parameter estimation values a, b, and c can be determined in the following manner:
[0082]
[0083] Among them, u(t i ) Here, the following matrix equation can be determined by the above formula:
[0084]
[0085] Afterwards, the above matrix equation can be solved based on the historical digital quantities to obtain the values of a, b and c.
[0086] In an optional embodiment, predicting the target digital quantity at the time when the GNSS navigation signal is lost according to the target fitting function specifically includes the following steps:
[0087] Based on the GNSS navigation signal loss period and the target fitting function, a target digital quantity is determined; wherein the signal loss period is used to indicate a target time period starting from the moment of signal loss.
[0088] In an embodiment of the present disclosure, here, when the loop filtering unit fails to receive the clock error data normally (ie, detects that the GNSS navigation signal is lost), the loop filtering unit may determine the standby digital quantity of the specified time period as the historical digital quantity.
[0089] Afterwards, the loop filter unit may send the historical digital quantity to the digital fitting and predictor unit.
[0090] After receiving the historical digital quantities, the digital fitting and predictor unit may determine a target fitting function based on the historical digital quantities.
[0091] Afterwards, the digital fitting and predictor unit may predict the digital quantity corresponding to the target time period based on the target fitting function to obtain the target digital quantity.
[0092] Here, the target time period can be determined according to the time when the GNSS navigation signal is lost. For example, if the GNSS navigation signal is lost for multiple consecutive times, the target time period is the time period corresponding to the consecutive lost GNSS navigation signals. If the GNSS navigation signal is lost for only one time, the target time period is the time when the GNSS navigation signal is lost.
[0093] Here, the digital quantity predicted at the time when the GNSS navigation signal is lost (i.e., the target digital quantity) can be determined based on the target fitting function. For example, when the GNSS antenna does not receive the GNSS navigation signal at the k+mth time, the digital quantity u(t k+m ) meets the following conditions:
[0094] u(t k+m )=a+b(t k+m )+c(t k+m) 2 Among them, the k-th moment is the moment when the GNSS antenna last receives the GNSS navigation signal. The (k + m)-th moment is the moment when the GNSS antenna cannot receive the GNSS navigation signal.
[0095] In an alternative embodiment, the local clock is enhanced in timekeeping according to a target digital quantity, which specifically includes the following steps:
[0096] Convert the target digital quantity and the historical digital quantity into analog quantities to obtain a first analog quantity and a second analog quantity respectively;
[0097] Adjust the output frequency of the local clock according to the first analog quantity and the second analog quantity.
[0098] Here, adjusting the output frequency of the local clock according to the first analog quantity and the second analog quantity specifically includes the following steps:
[0099] Generate a current signal and / or a voltage signal according to the first analog quantity and the second analog quantity;
[0100] Adjust the output frequency of the local clock according to the current signal and / or the voltage signal.
[0101] In the embodiments of the present disclosure, first, the clock characteristics of the local clock can be determined, that is, which physical quantity (current signal or voltage signal) the local clock needs to be adjusted based on. After that, the target digital quantity and the historical digital quantity can be respectively converted into a first analog quantity and a second analog quantity based on the clock characteristics.
[0102] For example, when the clock characteristic of the local clock is a current signal, the target digital quantity and the historical digital quantity are converted into a current signal, and the converted current is determined as the analog quantity.
[0103] Among them, each historical digital quantity can be converted into a second analog quantity. Here, each historical digital quantity corresponds to a second analog quantity.
[0104] Each target digital quantity can be converted into a first analog quantity. Here, each target digital quantity corresponds to a first analog quantity.
[0105] Here, after the first analog quantity and the second analog quantity are determined, the output frequency for adjusting the local clock can be determined based on the first analog quantity and the second analog quantity.
[0106] In the above embodiments, since the output frequency is determined by the clock error data (including all influencing factors of the local clock). Therefore, the aging of the local clock itself, the frequency-temperature characteristics, and the changes brought by other factors can be compensated by adjusting the output frequency of the local clock, thereby realizing the timekeeping enhancement of the GNSS timekeeping terminal in extreme cases.
[0107] Reference Figure 2 As shown, it is a specific flow chart of a method for enhancing GNSS timing provided by an embodiment of the present disclosure, wherein:
[0108] S10. When receiving the GNSS navigation signal, the GNSS antenna converts the GNSS navigation signal into a radio frequency signal.
[0109] S20, processing the GNSS navigation signal to obtain the satellite navigation message and the original observation value of the GNSS navigation signal.
[0110] S30, solving the satellite navigation message and the original observation quantity to obtain the clock difference data between the satellite clock and the local clock.
[0111] S40, determining the digital quantity to be used according to the clock difference data, and storing the digital quantity to be used to obtain the historical digital quantity.
[0112] S50: constructing an initial fitting function based on the historical digital quantity and the historical moment corresponding to the historical digital quantity, and constructing an evaluation function of the initial fitting function.
[0113] S60: Solve the evaluation function to obtain parameter estimation values of the initial fitting function, and determine the target fitting function based on the parameter estimation values.
[0114] S70. Predicting a target digital value at the moment when the GNSS navigation signal is lost according to the target fitting function.
[0115] S80: Convert the target digital quantity and the historical digital quantity into analog quantities to obtain a first analog quantity and a second analog quantity respectively.
[0116] S90. Adjust the output frequency of the local clock according to the first analog quantity and the second analog quantity.
[0117] When this solution is actually implemented, the following technical effects can be achieved:
[0118] (1) The present disclosure first adopts the method of historical digital quantity fitting when the GNSS navigation signal is normal and subsequent digital quantity prediction when the GNSS navigation signal is lost, enabling the local clock to still adjust and compensate according to the digital quantity change rule when the GNSS navigation signal is normal even when the GNSS navigation signal is lost, converting the GNSS navigation signal loss state into a "quasi-GNSS navigation signal normal state", and thus realizing the timing enhancement of the GNSS timing terminal in extreme cases. Compared with the existing technical solutions, the proposal in this application does not directly utilize clock error data, does not require a large amount of test data for separately modeling the aging and frequency-temperature characteristics of the local clock, nor does it require complex algorithms; in addition, since the value of the digital quantity is very large, which is equivalent to amplifying the clock error data with a relatively small value, it is easier to show the influence brought by the aging and frequency-temperature characteristics of the local clock when the GNSS navigation signal is normal. The clock error data usually shows a non-trending straight line when the GNSS navigation signal is normal, and it is impossible to directly observe the influence brought by the aging and frequency-temperature characteristics of the local clock.
[0119] (2) The present disclosure directly absorbs all other influencing factors such as the aging of the local clock, frequency-temperature characteristics, circuit drift, hardware delay, and temperature characteristics into the digital quantity, uniformly regarded as an adjustment variable, and directly compensates for the changes brought by the aging of the local clock, frequency-temperature characteristics, and other influencing factors by compensating the digital quantity, thus no longer separately distinguishing and compensating for the aging and frequency-temperature characteristics. Compared with the prior art, the principle is simpler and the implementation is easier.
[0120] Those skilled in the art can understand that in the above method of the specific implementation manner, the writing order of each step does not mean a strict execution order that constitutes any limitation to the implementation process, and the specific execution order of each step should be determined according to its function and possible internal logic.
[0121] Based on the same inventive concept, the present disclosure embodiment also provides a GNSS timing enhancement system corresponding to the GNSS timing enhancement method. Since the principle of solving problems by the system in the present disclosure embodiment is similar to the above GNSS timing enhancement method in the present disclosure embodiment, the implementation of the system can refer to the implementation of the method, and the repeated parts will not be described again.
[0122] Refer to Figure 3 As shown in the figure, it is a schematic diagram of a GNSS timing enhancement system provided by the present disclosure embodiment. The system includes: a GNSS antenna, a GNSS receiving unit, an information solving unit, a loop filtering unit, a digital fitting and predictor unit, a digital-to-analog conversion unit, and a local clock, where:
[0123] The GNSS antenna is used to receive the GNSS navigation signal, and when receiving the GNSS navigation signal, convert the GNSS navigation signal into a radio frequency signal, and then send the radio frequency signal to the GNSS receiving unit.
[0124] The GNSS receiving unit is used to perform low-noise amplification, power division, filtering and digital intermediate frequency processing on the received radio frequency signal in sequence to obtain the original observation values of the satellite navigation message and the GNSS navigation signal, and send the original observation values of the satellite navigation message and the GNSS navigation signal to the information solution unit.
[0125] The information solution unit is used to solve the satellite navigation message and the original observation quantity, obtain the clock difference data between the satellite clock and the local clock, and send the clock difference data to the loop filter unit.
[0126] When the loop filtering unit receives the clock error data normally (i.e., no GNSS navigation signal loss is detected), the standby digital quantity is stored; when the clock error data is not received normally (i.e., the GNSS navigation signal loss is detected), the standby digital quantity for a specified time period before the GNSS navigation signal loss is determined as a historical digital quantity, and the historical digital quantity is sent to the digital fitting and predictor unit and the digital-to-analog conversion unit.
[0127] The digital fitting and prediction unit can determine the target fitting function based on the historical digital quantity, and determine the target digital quantity at the moment when the GNSS navigation signal is lost based on the target fitting function. Thereafter, the target digital quantity is sent to the digital-to-analog conversion unit.
[0128] The digital-to-analog conversion unit is used to convert the target digital quantity and the historical digital quantity into analog quantities to obtain a first analog quantity and a second analog quantity respectively, and adjust the output frequency of the local clock according to the first analog quantity and the second analog quantity.
[0129] This system determines the historical digital quantity to obtain the target fitting function. Since the digital quantity when the GNSS navigation signal is lost still evolves according to the change law of the historical digital quantity when the GNSS navigation signal is normal, the target digital quantity at the moment when the GNSS navigation signal is lost can be determined according to the target fitting function. Afterwards, the local clock is enhanced based on the target digital quantity. In addition, the historical digital quantity is determined based on the clock difference data, and the clock difference data contains all the influencing factors of the local clock. Therefore, the local clock can be enhanced based only on the determined target digital quantity, without considering other influencing factors, thereby improving the time efficiency of the timing.
[0130] Based on the same inventive concept, embodiments of the present disclosure also provide a GNSS timing enhancement device corresponding to the GNSS timing enhancement method. Since the principle of problem-solving of the device in the embodiments of the present disclosure is similar to that of the above GNSS timing enhancement method in the embodiments of the present disclosure, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be elaborated.
[0131] Referring Figure 4 As shown, it is a schematic diagram of a GNSS timing enhancement device provided by an embodiment of the present disclosure. The device includes: a determination module 11, a fitting module 12, and a timing module 13; wherein,
[0132] The determination module 11 is configured to, when detecting the loss of the GNSS navigation signal, obtain historical digital quantities determined based on the GNSS navigation signals at historical moments; wherein, the historical moments are the moments when the GNSS navigation signals are normal, and the historical digital quantities are used to represent the clock difference data information between the satellite clock and the local clock at the historical moments;
[0133] The fitting module 12 is configured to fit the historical digital quantities to obtain a target fitting function of the historical digital quantities;
[0134] The timing module 13 is configured to predict the target digital quantity at the moment when the GNSS navigation signal is lost according to the target fitting function, and perform timing enhancement on the local clock according to the target digital quantity.
[0135] In the embodiments of the present disclosure, by determining the historical digital quantities to obtain the target fitting function, since the digital quantities when the GNSS navigation signal is lost still evolve according to the variation law of the historical digital quantities when the GNSS navigation signal is normal. Thus, the target digital quantity at the moment when the GNSS navigation signal is lost can be determined according to the target fitting function. Then, timing enhancement is performed on the local clock based on the target digital quantity. And, the historical digital quantities are determined based on the clock difference data, and the clock difference data includes all influencing factors of the local clock. Therefore, timing enhancement can be performed on the local clock only based on the determined target digital quantity, without the need to additionally consider other influencing factors, improving the time efficiency of timing.
[0136] In a possible implementation manner, the determination module 11 is further configured to: receive the GNSS navigation signal through a GNSS antenna, and process the GNSS navigation signal to obtain the satellite navigation message and the original observations of the GNSS navigation signal;
[0137] Perform a solution on the satellite navigation message and the original observations to obtain the clock difference data between the satellite clock and the local clock;
[0138] Determine the digital quantity to be used according to the clock difference data, and store the digital quantity to be used to obtain the historical digital quantity.
[0139] In a possible implementation manner, the fitting module 12 is further configured to: construct an initial fitting function based on the historical digital quantity and the historical moment corresponding to the historical digital quantity, and construct an evaluation function of the initial fitting function; wherein, the evaluation function is used to measure the quality of the initial fitting function.
[0140] Solve the evaluation function to obtain the parameter estimation value of the initial fitting function, and determine the target fitting function based on the parameter estimation value; wherein, the parameter estimation value is the value of each coefficient in the target fitting function when the evaluation function is minimized.
[0141] In a possible implementation manner, the timing module 13 is further configured to: determine the target digital quantity based on the GNSS navigation signal loss period and the target fitting function; wherein, the signal loss period is used to indicate a target time period starting from the signal loss moment.
[0142] In a possible implementation manner, the timing module 13 is specifically configured to: convert the target digital quantity and the historical digital quantity into analog quantities to obtain a first analog quantity and a second analog quantity respectively.
[0143] Adjust the output frequency of the local clock according to the first analog quantity and the second analog quantity.
[0144] In a possible implementation manner, the timing module 13 is specifically configured to: generate a current signal and / or a voltage signal according to the first analog quantity and the second analog quantity.
[0145] Adjust the output frequency of the local clock according to the current signal and / or the voltage signal.
[0146] The description of the processing flow of each module in the device and the interaction flow between each module can refer to the relevant description in the above method embodiments, and will not be elaborated here.
[0147] Corresponding to Figure 1 the GNSS timing enhancement method in, the embodiments of the present disclosure further provide an electronic device 500, as Figure 5 shown, which is a schematic structural diagram of the electronic device 500 provided by the embodiments of the present disclosure, including:
[0148] A processor 51, a memory 52, and a bus 53; the memory 52 is used to store execution instructions, including an internal memory 521 and an external memory 522; here, the internal memory 521 is also called the main memory, which is used to temporarily store the operation data in the processor 51 and the data exchanged with the external memory 522 such as a hard disk. The processor 51 exchanges data with the external memory 522 through the internal memory 521. When the electronic device 500 runs, the processor 51 communicates with the memory 52 through the bus 53, so that the processor 51 executes the following instructions:
[0149] When detecting the loss of GNSS navigation signals, obtaining historical digital quantities determined based on GNSS navigation signals at historical moments; wherein, the historical moments are the moments when GNSS navigation signals are normal, and the historical digital quantities are used to represent the clock difference data information between the satellite clock and the local clock at the historical moments;
[0150] Fitting the historical digital quantities to obtain a target fitting function of the historical digital quantities;
[0151] Predicting the target digital quantity at the moment of GNSS navigation signal loss according to the target fitting function, and performing timing enhancement on the local clock according to the target digital quantity.
[0152] The embodiments of the present disclosure also provide a computer-readable storage medium, on which a computer program is stored. When the computer program is run by a processor, it executes the steps of the GNSS timing enhancement method described in the above method embodiments. Wherein, the storage medium can be a volatile or non-volatile computer-readable storage medium.
[0153] The embodiments of the present disclosure also provide a computer program product, which carries program codes. The instructions included in the program codes can be used to execute the steps of the GNSS timing enhancement method described in the above method embodiments. For details, refer to the above method embodiments and will not be elaborated here.
[0154] Among them, the above computer program product can be specifically implemented in a way of hardware, software or a combination thereof. In an optional embodiment, the computer program product is specifically embodied as a computer storage medium. In another optional embodiment, the computer program product is specifically embodied as a software product, such as a Software Development Kit (SDK), etc.
[0155] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the specific working processes of the systems and devices described above can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated herein. In several embodiments provided in the present disclosure, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For another example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the couplings or direct couplings or communication connections shown or discussed with each other can be through some communication interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.
[0156] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.
[0157] In addition, in each embodiment of the present disclosure, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.
[0158] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium executable by a processor. Based on such an understanding, the technical solution of the present disclosure, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present disclosure. The foregoing storage medium includes: various media that can store program codes such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks, or optical discs.
[0159] Finally, it should be noted that the above-described embodiments are only specific implementation manners of the present disclosure, used to illustrate the technical solutions of the present disclosure, rather than limiting them. The protection scope of the present disclosure is not limited thereto. Although the present disclosure has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: any person skilled in the technical field of the present disclosure can still modify the technical solutions recorded in the foregoing embodiments, or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure, and should all be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.
Claims
1. A method for enhancing GNSS time synchronization, characterized in that, Comprising: In the case of detecting the loss of GNSS navigation signals, obtaining historical digital quantities determined based on GNSS navigation signals at historical moments; wherein, the historical moments are the moments when the GNSS navigation signals are normal, and the historical digital quantities are used to represent the clock difference data information between the satellite clock and the local clock at the historical moments; Fitting the historical digital quantities to obtain a target fitting function of the historical digital quantities; Predicting a target digital quantity at the moment of GNSS navigation signal loss according to the target fitting function, and enhancing the timing of the local clock according to the target digital quantity.
2. The method according to claim 1, characterized in that, The historical digital quantities are obtained through the following processing: Receiving GNSS navigation signals through a GNSS antenna, and processing the GNSS navigation signals to obtain satellite navigation messages and original observations of the GNSS navigation signals; Solving the satellite navigation messages and the original observations to obtain clock difference data between the satellite clock and the local clock; Determining standby digital quantities according to the clock difference data, and storing the standby digital quantities to obtain the historical digital quantities.
3. The method according to claim 1, characterized in that, The fitting of the historical digital quantities to obtain a target fitting function of the historical digital quantities includes: Constructing an initial fitting function based on the historical digital quantities and the historical moments corresponding to the historical digital quantities, and constructing an evaluation function of the initial fitting function; wherein, the evaluation function is used to measure the quality of the initial fitting function; Solving the evaluation function to obtain parameter estimation values of the initial fitting function, and determining the target fitting function based on the parameter estimation values; wherein, the parameter estimation values are the values of the coefficients in the target fitting function when the evaluation function is minimized.
4. The method according to claim 1, wherein The predicting of the target digital quantity at the moment of GNSS navigation signal loss according to the target fitting function includes: Determining the target digital quantity based on the GNSS navigation signal loss period and the target fitting function; wherein, the signal loss period is used to indicate a target time period starting from the signal loss moment.
5. The method according to claim 1, characterized in that, The enhancing of the timing of the local clock according to the target digital quantity includes: Converting the target digital quantity and the historical digital quantity into analog quantities to obtain a first analog quantity and a second analog quantity respectively; Adjusting the output frequency of the local clock according to the first analog quantity and the second analog quantity.
6. The method according to claim 5, characterized in that, The adjusting of the output frequency of the local clock according to the first analog quantity and the second analog quantity includes: Generating a current signal and / or a voltage signal according to the first analog quantity and the second analog quantity; Adjusting the output frequency of the local clock according to the current signal and / or the voltage signal.
7. A device for enhancing GNSS time synchronization, characterized in that, Comprising: A determination module, configured to obtain historical digital quantities determined based on GNSS navigation signals at historical moments in the case of detecting the loss of GNSS navigation signals; wherein, the historical moments are the moments when the GNSS navigation signals are normal, and the historical digital quantities are used to represent the clock difference data information between the satellite clock and the local clock at the historical moments; A fitting module, configured to fit the historical digital quantities to obtain a target fitting function of the historical digital quantities; A timing module, configured to predict a target digital quantity at the moment of GNSS navigation signal loss according to the target fitting function, and perform timing enhancement on the local clock according to the target digital quantity.
8. An electronic device, characterized in that, It includes: A processor, a memory and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device runs, the processor communicates with the memory through the bus. When the machine-readable instructions are executed by the processor, the steps of the GNSS timing enhancement method according to any one of claims 1 / 6 are performed.
9. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium. When the computer program is run by the processor, the steps of the GNSS timing enhancement method according to any one of claims 1 to 6 are performed.
10. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, the steps of the GNSS timing enhancement method according to any one of claims 1 to 6 are implemented.