Filtering and smoothing method and device for GNSS post-processing clock error
By using the clock difference correction amount at the previous moment and the frequency difference observation value in the GNSS receiver for extrapolation, and adjusting the clock difference correction amount in combination with the pseudorange, Doppler residual and satellite geometric distribution at the current moment, the clock difference correction amount is solved The problem of missing clock difference caused by satellite signal interference achieves stability and accuracy of timing results.
Patent Information
- Application Number
- CN202411254591.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-09
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2044-09-09
AI Technical Summary
When the satellite signal is disturbed or lost lock, the observation quantity and quality of the GNSS receiver cannot guarantee, resulting in the missing clock difference value, affecting the accuracy and continuity of the timing results.
By extrapolation by using the clock difference correction amount and frequency difference observation value at the previous moment, the predicted value of the clock difference correction amount is obtained, and reasonable judgment is made based on the pseudorange, Doppler residual and satellite geometric distribution at the current moment. Adjust the trusted clock difference value. If the difference value is greater than the preset value, use the trusted clock difference value to adjust the timing result. If it is within the preset range, use the improved clock difference correction predictor for adjustment.
Ensure the continuity and accuracy of timing results, reduce field values and jump points, and improve the stability of timing process.
Smart Images
Figure CN118759545B_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of GNSS positioning and timing technology, and in particular to a filtering and smoothing method and device for GNSS post-processing clock error. Background Art
[0002] The internal clock of a GNSS receiver is usually a quartz clock, which is less accurate than an atomic clock. Therefore, there is an error between the internal clock of the receiver and the system standard time, so the receiver needs to constantly correct the error of its own clock. GNSS timing generally uses a GNSS receiver to continuously receive satellite signals and perform pseudo-range measurements and clock error calculations to obtain the receiver clock error and correct its deviation to achieve high-precision time synchronization with the system standard time.
[0003] Normally, in the field of GNSS positioning and timing, the receiver receives signals from at least four satellites, calculates the corresponding pseudo-ranges of the satellites, and uses least squares or Kalman filtering to solve its own three-dimensional position and clock error. The receiver's local clock can be corrected using the solved clock error correction to achieve accurate timing. However, when the satellite signal is interfered with, blocked, or lost, the quantity and quality of the observations cannot be guaranteed, and the solution process cannot proceed or converge, which will lead to the loss of clock error values, and ultimately affect the accuracy and continuity of the timing results.
[0004] In order to solve the problems of timing continuity and accuracy, existing technologies often integrate multiple time sources to build a multi-level, multi-redundant time synchronization system. When one time source is unavailable, switch to other time sources to ensure the continuous operation of the system. At present, the GNSS timing field often uses external atomic clocks for taming to provide additional redundant time information. By observing GNSS signals and analyzing relevant time information including receiver clock errors, after obtaining accurate and stable time and frequency references, the local atomic clock is tamed to obtain better timing accuracy and stability. Summary of the invention
[0005] Based on this, it is necessary to provide a filtering and smoothing method and device for GNSS post-processing clock error in response to the above technical problems.
[0006] A filtering and smoothing method for GNSS post-processing clock error, the method comprising:
[0007] According to the clock error correction value and the frequency error observation value at the previous moment, the predicted value of the clock error correction value is obtained;
[0008] According to the credible clock error value at the current moment, the predicted value of the clock error correction is smoothed to obtain an improved predicted value of the clock error correction; wherein, if the current pseudorange, Doppler residual and satellite geometric distribution meet the preset threshold requirements, the credible clock error value at the current moment is the clock error value at the current moment, otherwise the credible clock error value at the current moment is the predicted value of the clock error correction;
[0009] The predicted value of the improved clock error correction is compared with the credible clock error value at the current moment. If the difference between the two is greater than a preset value, the timing result is adjusted according to the credible clock error value at the current moment. If the difference between the two is within a preset range, the timing result is adjusted according to the predicted value of the improved clock error correction.
[0010] In one embodiment, the method further includes: obtaining a predicted value of the clock error correction according to the clock error correction and the frequency error observation at the previous moment:
[0011] ;
[0012] in, is the predicted value of the clock correction at the current time, and are respectively the clock correction and frequency difference observation values at the previous moment.
[0013] In one embodiment, the method further includes: performing smoothing processing on the predicted value of the clock error correction according to the credible clock error value at the current moment, and obtaining an improved predicted value of the clock error correction:
[0014] ;
[0015] in, Indicates the reliable clock difference value of the current time. represents the smoothing weight, Represents the predicted value of the improved clock correction.
[0016] A filtering and smoothing device for GNSS post-processing clock error, the device comprising:
[0017] The clock error correction value prediction module is used to obtain the clock error correction value prediction value according to the clock error correction value and the frequency error observation value at the previous moment;
[0018] A smoothing processing module is used to smooth the predicted value of the clock error correction according to the credible clock error value at the current moment to obtain an improved predicted value of the clock error correction; wherein, if the current pseudorange, Doppler residual and satellite geometric distribution meet the preset threshold requirements, the credible clock error value at the current moment is the clock error value at the current moment, otherwise the credible clock error value at the current moment is the predicted value of the clock error correction;
[0019] A smoothing reset module is used to compare the predicted value of the improved clock error correction amount with the credible clock error value at the current moment. If the difference between the two is greater than a preset value, the timing result is adjusted according to the credible clock error value at the current moment. If the difference between the two is within a preset range, the timing result is adjusted according to the predicted value of the improved clock error correction amount.
[0020] In one embodiment, the clock error correction value prediction module is further used to obtain the clock error correction value prediction value according to the clock error correction value and the frequency error observation value at the previous moment:
[0021] ;
[0022] in, is the predicted value of the clock correction at the current time, and are respectively the clock correction and frequency difference observation values at the previous moment.
[0023] In one embodiment, the smoothing processing module is further used to perform smoothing processing on the predicted value of the clock error correction according to the credible clock error value at the current moment, and obtain an improved predicted value of the clock error correction as follows:
[0024] ;
[0025] in, Indicates the reliable clock difference value of the current time. represents the smoothing weight, Represents the predicted value of the improved clock correction.
[0026] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:
[0027] According to the clock error correction value and the frequency error observation value at the previous moment, the predicted value of the clock error correction value is obtained;
[0028] According to the credible clock error value at the current moment, the predicted value of the clock error correction is smoothed to obtain an improved predicted value of the clock error correction; wherein, if the current pseudorange, Doppler residual and satellite geometric distribution meet the preset threshold requirements, the credible clock error value at the current moment is the clock error value at the current moment, otherwise the credible clock error value at the current moment is the predicted value of the clock error correction;
[0029] The predicted value of the improved clock error correction is compared with the credible clock error value at the current moment. If the difference between the two is greater than a preset value, the timing result is adjusted according to the credible clock error value at the current moment. If the difference between the two is within a preset range, the timing result is adjusted according to the predicted value of the improved clock error correction.
[0030] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the following steps:
[0031] According to the clock error correction value and the frequency error observation value at the previous moment, the predicted value of the clock error correction value is obtained;
[0032] According to the credible clock error value at the current moment, the predicted value of the clock error correction is smoothed to obtain an improved predicted value of the clock error correction; wherein, if the current pseudorange, Doppler residual and satellite geometric distribution meet the preset threshold requirements, the credible clock error value at the current moment is the clock error value at the current moment, otherwise the credible clock error value at the current moment is the predicted value of the clock error correction;
[0033] The predicted value of the improved clock error correction is compared with the credible clock error value at the current moment. If the difference between the two is greater than a preset value, the timing result is adjusted according to the credible clock error value at the current moment. If the difference between the two is within a preset range, the timing result is adjusted according to the predicted value of the improved clock error correction.
[0034] The filtering and smoothing processing method, device, computer equipment and storage medium of the above-mentioned GNSS post-processing clock error, in order to solve the problems of missing clock error correction and many wild values in the timing process, firstly extrapolate the clock error correction and frequency error observation value at the previous moment to obtain the clock error correction prediction value, and then make a rationality judgment based on the current pseudorange, Doppler residual and satellite geometric distribution. If the current pseudorange, Doppler residual and satellite geometric distribution meet the preset threshold requirements, then the credible clock error value at the current moment is the clock error value at the current moment, otherwise the credible clock error value at the current moment is the clock error correction prediction value, which can ensure the accuracy of the extrapolation, and then compare the improved clock error correction prediction value with the credible clock error value at the current moment. If the difference between the two is greater than the preset value, the timing result is adjusted according to the credible clock error value at the current moment. If the difference between the two is within the preset range, the timing result is adjusted according to the improved clock error correction prediction value. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Figure 1 is a flow chart of a timing process of a receiver in one embodiment;
[0036] Figure 2 1. It is a flowchart of a filtering and smoothing method for GNSS post-processing clock error in one embodiment;
[0037] Figure 3 1 is a schematic diagram of the overall process of a filtering and smoothing method for GNSS post-processing clock error in one embodiment;
[0038] Figure 4 It is a structural block diagram of a filtering and smoothing processing device for GNSS post-processing clock error in one embodiment;
[0039] Figure 5 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION
[0040] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0041] In the GNSS timing process, the receiver clock is usually corrected using the clock error correction calculated by the least squares or Kalman filter to complete the timing process. When the satellite signal is interfered with or lost, the quantity and quality of the observations cannot be guaranteed, resulting in the loss of clock error values, making it impossible to use the receiver clock error to provide timing to the user. The present invention uses the clock error and frequency error information of the previous epoch to compensate for the missing clock error value, thereby ultimately ensuring the continuity and accuracy of the timing results. The timing process of the receiver is as follows: Figure 1 shown.
[0042] In one embodiment, Figure 2 As shown in FIG. 1 , a filtering and smoothing method for GNSS post-processing clock error is provided, and the method is applied to Figure 1 The calculation of the clock correction value in is taken as an example to illustrate, including the following steps:
[0043] Step 202, obtaining a predicted value of the clock error correction according to the clock error correction and the frequency error observation at the previous moment.
[0044] In this step, this extrapolation is used for filtering. No matter what causes the clock correction to be missing, the predicted value of the clock correction can be used when the clock correction is needed for timing operations, thereby ensuring the continuity of the clock correction.
[0045] Step 204, smoothing the predicted value of the clock error correction according to the credible clock error value at the current moment to obtain an improved predicted value of the clock error correction.
[0046] If the current pseudorange, Doppler residual and satellite geometric distribution meet the preset threshold requirements, the credible clock error value at the current moment is the clock error value at the current moment; otherwise, the credible clock error value at the current moment is the predicted value of the clock error correction.
[0047] Among the parameters for judging the rationality of the clock correction, the pseudorange residual represents, to a certain extent, the accuracy of the current positioning result and clock error based on the pseudorange solution; the Doppler residual represents, to a certain extent, the accuracy of the current constant speed result and frequency error based on the Doppler solution; the geometric distribution of the satellite is reflected in the Dop, i.e., the precision factor, which can reflect the positioning error; since the clock correction is related to the solution of the positioning result, the precision factor can also reflect the accuracy of the clock correction.
[0048] The rationality judgment thresholds used above are all based on theoretically reasonable derivation of the value range, and are finally set after testing by collecting multiple groups of data from different time periods and different frequency points.
[0049] Since the predicted value of the clock correction is obtained by extrapolating the clock correction and clock change at the previous moment, its accuracy is heavily dependent on the accuracy of the relevant data at the previous moment. In the case of low quality of observations, poor satellite geometry, etc., the accuracy of the relevant data at the previous moment cannot be guaranteed, which may cause the predicted value of the clock correction to jump, resulting in wild values in the final timing result. In order to make the clock correction used for timing as stable as possible, this step further smoothes the clock correction that will eventually be used for timing on the basis of the aforementioned filtering.
[0050] Step 206, compare the predicted value of the improved clock error correction amount with the credible clock error value at the current moment. If the difference between the two is greater than a preset value, adjust the timing result according to the credible clock error value at the current moment. If the difference between the two is within a preset range, adjust the timing result according to the predicted value of the improved clock error correction amount.
[0051] This step ensures the reliability of the clock correction used for filtering, and prevents the clock correction used after smoothing from showing an erroneous growth trend, causing the timing results to become increasingly biased.
[0052] In the filtering and smoothing method of the above-mentioned GNSS post-processing clock error, in order to solve the problems of missing clock error correction and many wild values in the timing process, firstly, the clock error correction and frequency difference observation values at the previous moment are extrapolated to obtain the predicted value of the clock error correction, and then a rationality judgment is made based on the current pseudorange, Doppler residual and satellite geometric distribution. If the current pseudorange, Doppler residual and satellite geometric distribution meet the preset threshold requirements, the credible clock error value at the current moment is the clock error value at the current moment, otherwise the credible clock error value at the current moment is the predicted value of the clock error correction, which can ensure the accuracy of the extrapolation, and then the improved predicted value of the clock error correction is compared with the credible clock error value at the current moment. If the difference between the two is greater than the preset value, the timing result is adjusted according to the credible clock error value at the current moment. If the difference between the two is within the preset range, the timing result is adjusted according to the improved predicted value of the clock error correction.
[0053] In one embodiment, the predicted value of the clock error correction is obtained based on the clock error correction value and the frequency error observation value at the previous moment:
[0054] ;
[0055] in, is the predicted value of the clock correction at the current time, and are respectively the clock correction and frequency difference observation values at the previous moment.
[0056] Specifically, if the pseudorange, Doppler residual and satellite geometric distribution meet the threshold requirements for reasonable judgment, the clock error value can be trusted. Get the clock difference of the current time ; If the rationality judgment fails, the predicted value of the current time clock correction is taken As a reliable clock error .
[0057] Specifically, the rationality judgment is based on the pseudorange residual, Doppler residual and satellite geometric distribution to judge the stability and credibility of the current solution, and select the reliable clock error and frequency error from the predicted value and the observed value. To a certain extent, it represents the accuracy of the current positioning results and clock errors based on pseudorange solution. The calculation formula is as follows:
[0058] ;
[0059] In the formula is the distance measurement between the receiver and the satellite. is the pseudorange value. is the predicted value of the clock difference, which is the clock difference value at the current moment .
[0060] Doppler residual To a certain extent, it represents the accuracy of the current Doppler-based constant speed results and frequency difference. The calculation formula is as follows:
[0061] ;
[0062] In the formula is the receiver velocity measurement, is the Doppler observation value, is the estimated value of clock drift.
[0063] The geometric distribution of satellites is reflected in the spatial position precision factor In general, the precision factor can reflect the situation of positioning error. Since the clock correction is related to the solution of positioning results, the precision factor can also reflect the accuracy of the clock correction. The calculation formula of spatial position precision factor is as follows:
[0064] ;
[0065] In the formula The diagonal elements representing the weight matrix are determined by the geometric distribution of satellites relative to the user.
[0066] The value range is reasonably deduced based on theory, and the thresholds are set after testing multiple groups of data in different time periods and frequencies. , the formula for rationality judgment is: , Represents logical AND.
[0067] If the pseudorange residuals, Doppler residuals and satellite geometric distribution meet the threshold requirements for reasonable judgment, the clock error value can be trusted. Get the clock difference of the current time ; If the rationality judgment fails, the clock difference value is credible Get the predicted value of the current clock correction .
[0068] In one embodiment, the predicted value of the clock error correction is smoothed according to the credible clock error value at the current moment, and the improved predicted value of the clock error correction is obtained as follows:
[0069] ;
[0070] in, Indicates the reliable clock difference value of the current time. represents the smoothing weight, Represents the predicted value of the improved clock correction.
[0071] In order to obtain the improved clock correction value prediction Then, according to the current reliable clock difference Compared with the current improved clock correction prediction value The difference between the clock and the smooth reset condition is judged. If the difference is too large, the current reliable clock difference is As the final clock correction, the clock drift is updated and the smoothing depth is reset (i.e. the number of consecutive times the smoothed clock correction is used to generate the predicted value); if the difference does not reach the reset condition, the improved clock correction predicted value is used as the final clock correction to adjust the timing result to ensure the continuity and stability of the timing result. The final clock correction will be used as the input parameter of the next filtering to generate the predicted value at the next moment. The overall flow chart is as follows: Figure 3 shown.
[0072] In summary, the present invention can use extrapolated values to ensure the stability and continuity of timing results when there is no clock correction due to lack of observations or low quality of observations, and reduce the wild values and jump points of the timing results to a certain extent, making the overall timing performance smoother.
[0073] It should be understood that although Figure 2 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 2 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.
[0074] In one embodiment, Figure 4 As shown, a filtering and smoothing processing device for GNSS post-processing clock error is provided, comprising: a clock error correction amount prediction value module 402, a smoothing processing module 404 and a smoothing reset module 406, wherein:
[0075] The clock error correction value prediction module 402 is used to obtain the clock error correction value prediction value according to the clock error correction value and the frequency error observation value at the previous moment;
[0076] The smoothing processing module 404 is used to smooth the clock error correction value prediction value according to the credible clock error value at the current moment to obtain an improved clock error correction value prediction value; wherein, if the current pseudorange, Doppler residual and satellite geometric distribution meet the preset threshold requirements, the credible clock error value at the current moment is the clock error value at the current moment, otherwise the credible clock error value at the current moment is the clock error correction value prediction value;
[0077] The smoothing reset module 406 is used to compare the predicted value of the improved clock error correction amount with the credible clock error value at the current moment. If the difference between the two is greater than a preset value, the timing result is adjusted according to the credible clock error value at the current moment. If the difference between the two is within a preset range, the timing result is adjusted according to the predicted value of the improved clock error correction amount.
[0078] In one embodiment, the clock error correction value prediction module 402 is further used to obtain the clock error correction value prediction value according to the clock error correction value and the frequency error observation value at the previous moment:
[0079] ;
[0080] in, is the predicted value of the clock correction at the current time, and are respectively the clock correction and frequency difference observation values at the previous moment.
[0081] In one embodiment, the smoothing processing module 404 is further used to perform smoothing processing on the predicted value of the clock error correction according to the credible clock error value at the current moment, and obtain an improved predicted value of the clock error correction as follows:
[0082] ;
[0083] in, Indicates the reliable clock difference value of the current time. represents the smoothing weight, Represents the predicted value of the improved clock correction.
[0084] For the specific definition of the filtering and smoothing processing device for GNSS post-processing clock error, please refer to the definition of the filtering and smoothing processing method for GNSS post-processing clock error in the above text, which will not be repeated here. Each module in the above-mentioned filtering and smoothing processing device for GNSS post-processing clock error can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.
[0085] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 5 As shown. The computer device includes a processor, a memory, a network interface and a database connected through a system bus. Among them, the processor of the computer device is used 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, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store historical clock error and frequency error data. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a filtering and smoothing method for GNSS post-processing clock error is implemented.
[0086] Those skilled in the art will understand that Figure 5The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.
[0087] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method in the above embodiment when executing the computer program.
[0088] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method in the above embodiment are implemented.
[0089] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.
[0090] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0091] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.
Claims
1. A filtering and smoothing method for GNSS post-processing clock error, It is characterized in that The method comprises: According to the clock error correction value and the frequency error observation value at the previous moment, the predicted value of the clock error correction value is obtained; According to the credible clock error value at the current moment, the predicted value of the clock error correction is smoothed to obtain an improved predicted value of the clock error correction; wherein, if the current pseudorange, Doppler residual and satellite geometric distribution meet the preset threshold requirements, the credible clock error value at the current moment is the clock error value at the current moment, otherwise the credible clock error value at the current moment is the predicted value of the clock error correction; Compare the predicted value of the improved clock error correction with the credible clock error value at the current moment. If the difference between the two is greater than a preset value, adjust the timing result according to the credible clock error value at the current moment. If the difference between the two is within a preset range, adjust the timing result according to the predicted value of the improved clock error correction; According to the reliable clock error value at the current moment, the predicted value of the clock error correction is smoothed to obtain an improved predicted value of the clock error correction, including: According to the reliable clock error value at the current moment, the predicted value of the clock error correction is smoothed to obtain the improved predicted value of the clock error correction: in, Indicates the reliable clock difference value of the current time. is the predicted value of the clock correction at the current time, represents the smoothing weight, Represents the predicted value of the improved clock correction.
2. The method according to claim 1, It is characterized in that The step of obtaining a predicted value of the clock error correction according to the clock error correction and the frequency error observation at the previous moment includes: According to the clock correction and frequency difference observations at the previous moment, the predicted clock correction is: in, and are respectively the clock correction and frequency difference observation values at the previous moment.
3. A filtering and smoothing device for GNSS post-processing clock error, It is characterized in that The device comprises: The clock error correction value prediction module is used to obtain the clock error correction value prediction value according to the clock error correction value and the frequency error observation value at the previous moment; A smoothing processing module is used to smooth the predicted value of the clock error correction according to the credible clock error value at the current moment to obtain an improved predicted value of the clock error correction; wherein, if the current pseudorange, Doppler residual and satellite geometric distribution meet the preset threshold requirements, the credible clock error value at the current moment is the clock error value at the current moment, otherwise the credible clock error value at the current moment is the predicted value of the clock error correction; A smoothing reset module, used to compare the predicted value of the improved clock error correction amount with the credible clock error value at the current moment, and if the difference between the two is greater than a preset value, adjust the timing result according to the credible clock error value at the current moment; if the difference between the two is within a preset range, adjust the timing result according to the predicted value of the improved clock error correction amount; The smoothing processing module is also used to perform smoothing processing on the predicted value of the clock error correction according to the credible clock error value at the current moment, and obtain an improved predicted value of the clock error correction as follows: in, Indicates the reliable clock difference value of the current time. is the predicted value of the clock correction at the current time, represents the smoothing weight, Represents the predicted value of the improved clock correction.
4. The device according to claim 3, It is characterized in that The clock error correction value prediction module is also used to obtain the clock error correction value prediction value according to the clock error correction value and the frequency error observation value at the previous moment: in, and are respectively the clock correction and frequency difference observation values at the previous moment.