CN115808867A - Comprehensive pulsar time determination method and system based on timing residual error - Google Patents
Comprehensive pulsar time determination method and system based on timing residual error Download PDFInfo
- Publication number
- CN115808867A CN115808867A CN202211514638.8A CN202211514638A CN115808867A CN 115808867 A CN115808867 A CN 115808867A CN 202211514638 A CN202211514638 A CN 202211514638A CN 115808867 A CN115808867 A CN 115808867A
- Authority
- CN
- China
- Prior art keywords
- pulsar
- optimal
- error
- timing
- comprehensive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
The invention relates to the technical field of pulsar time, in particular to a comprehensive pulsar time determination method and a comprehensive pulsar time determination system based on timing residual errors, which comprise the following steps: preprocessing and filtering the initial timing residual error of each screened optimal pulsar to obtain a corresponding smooth timing residual error; and selecting a reference pulsar, and performing equidistant downsampling on the smooth timing residual error and the initial error of each optimal pulsar according to the number of observation points of the reference pulsar to obtain a corresponding downsampled timing residual error and a downsampled initial error, thereby obtaining the comprehensive pulsar time stability. According to the invention, the comprehensive pulsar time stability is obtained through preprocessing, vondrak filtering, down-sampling and weighted average algorithm, so that not only is alignment of all points of pulsar timing residual errors ensured and stronger interpretability achieved, but also the comprehensive pulsar time stability is improved by more than 1 order of magnitude compared with the average level of single pulsar stability, and the reliability is high.
Description
Technical Field
The invention relates to the technical field of pulsar time, in particular to a comprehensive pulsar time determination method and system based on timing residual errors.
Background
In a positioning navigation time service (PNT) system, time service determines whether positioning and navigation can be successful, and high-precision time service is based on high-precision high-stability timekeeping to ensure stable and safe operation of various industries such as communication, finance and the like, wherein pulsar belongs to a neutron star and has the characteristics of strong magnetic field, small volume, large density and high autorotation speed, and a ground test station can receive high-energy rays emitted by two poles of pulsar every time the pulsar autorotates for one period -19 ～10 -21 The most stable clock in the nature is honored by the reputation, and the stability of pulsar timing residual error can be used for weighing pulsar emission high energy impulse signal's stability.
At present, when stability evaluation is carried out on comprehensive pulsar time, the traditional pulsar time generation method mainly adopts a Vondrak filtering pretreatment and a cubic spline interpolation method to analyze the pulsar timing stability of the pulsar time, but in the process of evaluating the comprehensive pulsar time by using the traditional method, not only can alignment of all points of pulsar timing residual errors be guaranteed, but also the timing total residual error and the timing total error are difficult to obtain confidence, and only the Vondrak filtering is adopted to carry out data processing, so that the contribution to the timing stability is limited.
Disclosure of Invention
The invention provides a comprehensive pulsar time determination method and system based on timing residual errors, and solves the technical problems that a traditional pulsar time generation method cannot ensure that all points of pulsar timing residual errors are aligned, so that timing total residual errors and total errors are difficult to obtain, and contribution to timing stability is limited only by adopting Vondrak filtering for data processing.
In order to solve the technical problems, the invention provides a comprehensive pulsar time determination method and system based on timing residual errors.
In a first aspect, the present invention provides a method for determining a synthetic pulsar time based on a timing residual, the method comprising the steps of:
selecting at least two optimal pulsar according to preset optimal screening conditions, and acquiring an initial timing residual error and an initial error of each optimal pulsar;
sequentially preprocessing and filtering the initial timing residual error of each optimal pulsar to obtain a corresponding smooth timing residual error;
selecting a reference pulsar, and performing equidistant downsampling on the smooth timing residual error and the initial error of each optimal pulsar according to the number of observation points of the reference pulsar to obtain a corresponding downsampled timing residual error and a downsampled initial error;
obtaining the stability of each optimal pulsar according to the timing residual after the down-sampling and the initial error after the down-sampling;
obtaining a comprehensive weighting residual error and a comprehensive weighting error according to the stability of each optimal pulsar;
and obtaining the comprehensive pulsar time stability according to the comprehensive weighting residual error, the comprehensive weighting error and the julian day of the reference pulsar.
In a further embodiment, the preset optimal screening conditions include:
the optimal pulsar is a millisecond pulsar, the observation time span of the optimal pulsar needs to meet a preset observation time span threshold value, and the number of observation points needs to meet a preset observation point threshold value.
In a further embodiment, the step of sequentially preprocessing and filtering the initial timing residual of each optimal pulsar to obtain a corresponding smooth timing residual includes:
performing gross error point extraction on the initial timing residual error of each optimal pulsar by using an absolute median deviation method;
zeroing the gross error point of each optimal pulsar, and performing interpolation processing on the gross error point by using a piecewise cubic Hermite interpolation method to obtain a preprocessed initial timing residual error;
and performing filtering and noise reduction treatment on the preprocessed initial timing residual error by using Vondrak filtering to obtain a smooth timing residual error of each optimal pulsar.
In a further embodiment, the calculation formula of the integrated weighted residual and the integrated weighted error is:
wherein, the first and the second end of the pipe are connected with each other,
in the formula res General assembly Represents the integrated weighted residual; res is i ' represents the timing residual after the down-sampling of the ith optimal pulsar; err (r) General (1) Representing the composite weighted error; err (r) i ' represents the initial error after the down-sampling of the ith optimal pulsar; w is a i Representing the weight of the ith optimal pulsar; sigma zi And the stability of the ith optimal pulsar is shown.
In a further embodiment, the integrated pulsar-time stability is calculated by the formula:
in the formula, σ General assembly (τ) represents integrated pulsar-time stability; τ represents a time scale; c. C 3 Representing a cubic polynomial coefficient; res is General (1) Representing the integrated weighted residual; x (MJD 3) represents a cubic polynomial fitting function; MJD3 represents the julian day of the reference pulsar; err (r) General assembly Representing the integrated weighted error.
In a further embodiment, the step of selecting a reference pulsar comprises: and screening all the optimal pulsar according to preset reference screening conditions to obtain a reference pulsar, and taking the reference pulsar observation julian day as a reference julian day.
In further embodiments, the preset reference screening conditions include: and selecting the optimal pulsar with the least observation points as a reference pulsar.
In a second aspect, the present invention provides a timing residual based integrated pulsar time determination system, the system comprising:
the optimal pulsar obtaining module is used for selecting at least two optimal pulsars according to preset optimal screening conditions and obtaining an initial timing residual error and an initial error of each optimal pulsar;
the pulsar data processing module is used for sequentially preprocessing and filtering the initial timing residual error of each optimal pulsar to obtain a corresponding smooth timing residual error; the method is also used for selecting a reference pulsar and performing equidistant downsampling on the smooth timing residual error and the initial error of each optimal pulsar according to the number of observation points of the reference pulsar to obtain a corresponding downsampled timing residual error and a downsampled initial error; obtaining the stability of each optimal pulsar according to the timing residual after the down-sampling and the initial error after the down-sampling;
the timing residual weighting module is used for obtaining comprehensive weighting residual and comprehensive weighting error according to the stability of each optimal pulsar;
and the comprehensive pulsar time determining module is used for obtaining the comprehensive pulsar time stability according to the comprehensive weighting residual error, the comprehensive weighting error and the julian day of the reference pulsar.
In a third aspect, the present invention further provides a computer device, including a processor and a memory, where the processor is connected to the memory, the memory is used for storing a computer program, and the processor is used for executing the computer program stored in the memory, so that the computer device executes the steps for implementing the method.
In a fourth aspect, the present invention also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the above method.
The invention provides a timing residual error-based comprehensive pulsar time determination method and a timing residual error-based comprehensive pulsar time determination system. Compared with the prior art, the method is based on pulsar timing residual processing of preprocessing, vondrak filtering and downsampling, determines the comprehensive pulsar time, and simultaneously utilizes a weighted average pulsar time algorithm to improve the stability of the comprehensive pulsar time by more than 1 order of magnitude compared with the stability average level of a single pulsar, so that the precision and the reliability of the comprehensive pulsar time are improved, and the method is high in practicability.
Drawings
Fig. 1 is a schematic flow chart of a method for determining a synthetic pulsar time based on a timing residual according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a synthetic pulsar-time calculation process provided by an embodiment of the present invention;
fig. 3 is a schematic diagram of comparison of timing residuals before and after a coarse difference point of the pulsar J0437-4715 is removed by an MAD method according to an embodiment of the present invention;
FIG. 4 is a comparison diagram of timing residuals before and after the pre-processing of pulsar J0437-4715 provided by the embodiment of the present invention;
FIG. 5 is a comparison diagram of pulsar J0437-4715 timing residuals before and after Vondrak filtering according to an embodiment of the present invention;
FIG. 6 is a schematic diagram illustrating the comparison between the integrated pulsar time stability and the stability of the optimal pulsar in single time according to an embodiment of the present invention;
FIG. 7 is a block diagram of a system for integrated pulsar-time determination based on timing residuals according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a computer device according to an embodiment of the present invention.
Detailed Description
The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, which are given solely for the purpose of illustration and are not to be construed as limitations of the invention, including the drawings which are incorporated herein by reference and for illustration only and are not to be construed as limitations of the invention, since many variations thereof are possible without departing from the spirit and scope of the invention.
Referring to fig. 1, an embodiment of the present invention provides a method for determining a synthetic pulsar time based on a timing residual, as shown in fig. 1, the method includes the following steps:
s1, selecting at least two optimal pulsar according to preset optimal screening conditions, and obtaining an initial timing residual error and an initial error of each optimal pulsar.
Specifically, in the present embodiment, according to a preset optimal screening condition, in IPTA2019-Release2, a plurality of optimal pulsar is screened from 37 pulsars observed by NANOGrav, and a Tempo2 software is used to perform an operation on an ephemeris file and a model parameter of each pulsar to obtain an initial timing residual error and an initial error of each optimal pulsar, where in the present embodiment, the preset optimal screening condition includes:
(1) The optimal pulsar is a millisecond pulsar; the rotation stability of the millisecond pulsar is high, and the timing residual error is small, so that the millisecond pulsar is used as one of basic requirements of the optimal pulsar;
(2) The observation time span of the optimal pulsar needs to satisfy a preset observation time span threshold value so as to calculate the long-term stability of the pulsar in a subsequent step and study the noise characteristics, in this embodiment, the preset observation time span threshold value is preferably set to be more than 10yr (i.e., 10 years);
(3) The observation point number (i.e., TOAs) of the optimal pulsar needs to satisfy a preset observation point number threshold value to improve the fitting precision of the timing model, and the preset observation point number threshold value is preferably set to be more than 8000 in the embodiment.
Based on the above optimal screening conditions, this example screened 8 pulsar as shown in table 1 from 37 pulsars observed by NANOGrav, and table 1 is as follows:
TABLE 1
It should be noted that although the PSR J0437-4715 pulsar has a long observation year, the TOAs in the original observation data is only 5302, which is far less than that of other pulsars, and if they are selected together, the number of points after down-sampling of other pulsars will be adversely affected to some extent, which is not favorable for improving the stability of the integrated pulsars, so this embodiment excludes the PSR J0437-4715 pulsars.
And S2, sequentially preprocessing and filtering the initial timing residual error of each optimal pulsar to obtain a corresponding smooth timing residual error.
In one embodiment, the step of sequentially preprocessing and filtering the initial timing residual of each optimal pulsar to obtain a corresponding smooth timing residual includes:
extracting gross error points of the initial timing residual error of each optimal pulsar by using an absolute median deviation method;
zeroing the gross error point of each optimal pulsar, and performing interpolation processing on the gross error point by using a piecewise cubic Hermite interpolation method to obtain a preprocessed initial timing residual error;
and performing filtering and noise reduction treatment on the preprocessed initial timing residual error by using Vondrak filtering to obtain a smooth timing residual error of each optimal pulsar.
As shown in fig. 2, in this embodiment, the initial timing residuals of the 8 optimal pulsar are respectively preprocessed and Vondrak filtered, wherein the preprocessing step adopts an absolute median offset Method (MAD) to extract coarse difference points of the pulsar timing residuals, which specifically includes:
in the formula, x j (j =1,2.. N.) represents the initial timing residual vector.
If x j If the above equation is satisfied, it indicates that the initial timing residual exceeds the gross error threshold, in this embodiment, the initial timing residual is taken as a gross error point, the gross error point is subjected to zeroing processing, and then the gross error point is subjected to interpolation processing by using a piecewise cubic Hermite interpolation method to obtain a preprocessed initial timing residual, so that the preprocessed initial timing residual is more reasonable and smooth, thereby avoiding a Runge phenomenon; after the initial timing residual is preprocessed, the embodiment further performs filtering and denoising processing on the preprocessed initial timing residual through von-randak filtering to filter out high-frequency noise.
It should be noted that although pulsar J0437-4715 is not included in 8 optimal pulsars, it can be used for demonstration experiments (the results of other 8 pulsars are similar), fig. 3 is a timing residual comparison diagram before and after the pulsars J0437-4715 remove the coarse difference point by the MAD method; FIG. 4 is a comparison diagram of timing residuals before and after preprocessing performed by pulsar J0437-4715, wherein in FIG. 4, a preprocessing curve with the Runge phenomenon is a curve generated by replacing cubic Hermite interpolation with cubic spline interpolation in preprocessing; FIG. 5 is a comparison of pulsar J0437-4715 timing residuals before and after Vondrak filtering.
And S3, selecting a reference pulsar, and performing equidistant downsampling on the smooth timing residual error and the initial error of each optimal pulsar according to the number of observation points of the reference pulsar to obtain the corresponding downsampled timing residual error and downsampled initial error.
Specifically, in this embodiment, all the optimal pulsar is screened according to a preset reference screening condition to obtain a reference pulsar, and the reference pulsar observation julian day is used as a reference julian day; wherein the preset reference screening conditions include: the optimal pulsar with the minimum observation point number (TOAs) is selected as a reference pulsar, and according to the optimal pulsar selected in table 1, the pulsar PSR J1643-1224 with the minimum TOAs is selected as the reference pulsar in the embodiment, and the observation julian day ((modified julian date, MJD)) range of the reference pulsar, that is, the MJD3 is used as the reference julian day.
Then, this example compares N i (i =1,2, \8230; 8) TOAs noted as the ith best pulsar, in particular, N = min { N { i }＝N 3 Wherein N is 3 TOAs of reference pulsar No. 3 PSR J1643-1224 in Table 1 are shown, and res is recorded in this example i And err i The smooth timing residual and the initial error of the ith optimal pulsar are respectively expressed as:
according to the observation number of the reference pulsar, performing equidistant downsampling on the smooth timing residual error and the initial error of each optimal pulsar to obtain a corresponding downsampled timing residual error and a downsampled initial error, aligning the timing residual error and the error number of each optimal pulsar through downsampling, and selecting the julian date of the reference pulsar as a unified condition during data processing to form an interpretable (credible) comprehensive pulsar, wherein the downsampled timing residual error and the downsampled initial error are respectively:
wherein res i ' represents the timing residual after the down-sampling of the ith optimal pulsar; err (r) i ' represents the initial error after the down-sampling of the ith optimal pulsar;<x>indicating that x is rounded off.
And S4, obtaining the stability of each optimal pulsar according to the timing residual after the down sampling and the initial error after the down sampling.
To eliminate the influence of linear frequency drift, the stability of pulsar is usually σ z Variance (also called Hadamard variance) evaluation, unlike Allan variance, etc., statistic z The calculation mode does not need to require that residual errors are distributed at equal intervals, and is particularly convenient for analyzing pulsar data, sigma z The calculation method of (after fitting) the timing residual with the time scale tau is fitted by using a cubic polynomial function, and the numerical value of the timing residual is determined by using a cubic polynomial coefficient c3, which specifically comprises the following steps: recording the total observation time of the data as T = T N -t 1 And divided into subsequences of equal interval τ, set t 0 For reference time, a least squares fit is made to each subsequence using a cubic polynomial function X (t), i.e.:
X(t)＝c 0 +c 1 (t-t 0 )+c 2 (t-t 0 ) 2 +c 3 (t-t 0 ) 3
wherein the stability sigma of each optimal pulsar zi The calculation formula of (τ) is specifically:
in the formula, t i (i =1,2, \8230;, n) indicates the observed time (in julian days) for the ith optimal pulsar, n =8 since 8 optimal pulsars were selected according to the method described above; x is the number of i Representing the timing residual error of the ith optimal pulsar; sigma i The error of the ith optimal pulsar is represented; tip bracket
Is represented on all subsequences by c 3 The inverse square of the uncertainty is weighted to make a weighted average.
And S5, obtaining a comprehensive weighted residual error and a comprehensive weighted error according to the stability of each optimal pulsar.
In one embodiment, the calculation formula of the integrated weighted residual and the integrated weighted error is:
wherein, the first and the second end of the pipe are connected with each other,
in the formula res General (1) Representing the integrated weighted residual; res i ' represents the timing residual after the down-sampling of the ith optimal pulsar; err (r) General assembly Representing the composite weighted error; err (r) i ' represents the initial error of the ith optimal pulsar after down sampling; w is a i Representing the weight value of the ith optimal pulsar; sigma zi And the stability of the ith optimal pulsar is shown.
And S6, obtaining the comprehensive pulsar time stability according to the comprehensive weighted residual error, the comprehensive weighted error and the reference julian day.
In one embodiment, the calculation formula of the integrated pulsar-time stability is as follows:
in the formula, σ General assembly (τ) represents integrated pulsar-time stability; τ represents a time scale; c. C 3 Indicating an error; res General assembly Representing the integrated weighted residual; x (MJD 3) represents a cubic polynomial fitting function; MJD3 represents the julian day of the reference pulsar; err (r) General assembly Representing the integrated weighted error.
In the embodiment, the reference pulsar is obtained by reference to the julian days MJD3 and the comprehensive weighted residual res General assembly And the combined weighted error err General (1) The integrated pulsar-time stability composed of 8 optimal pulsar is obtained through calculation, fig. 6 is a schematic diagram showing the comparison between the integrated pulsar-time stability and the stability of the 8 optimal pulsar in a single timekeeping mode, in fig. 6, the abscissa represents the time scale of calculating the stability, and the value is equal to the length of each subsequence (if the abscissa takes 0, the time scale tau takes a logarithmic value of 0, so tau is 1yr, sigma is z When calculating the stability, the observed data should be grouped and fitted by taking 1yr as a unit); ordinate represents σ z The logarithm of the stability value is shown in fig. 6, and the combined pulsar-time stability σ based on the classical weighted average algorithm is shown in this embodiment General assembly (τ) reached 1e-15.9 on a 22yr time scale, and table 2 shows the long and short term stability calculated for each of the 8 best pulsar, as shown below in table 2:
TABLE 2
The time scales of the long and short term stabilities in table 2 correspond to the left and right endpoints of the individual timekeeping curves of the 8 optimal pulsar in fig. 6, respectively, which are not specific values, but a range covering twice the span, because the observation time of each pulsar is different, and σ is different z The calculation of the stability is based on 2 in the time domainLogarithmically distributed; in fig. 6, since the single optimal pulsar PSR J1713+0747 with the highest stability under 22yr reaches only 1e to 15.0 (the observation time of PSR J1909 to 3744 is only half of 22yr, which is not taken into consideration), whereas the 22yr stability at the time of the integrated pulsar in fig. 6 is 1e to 15.9, it can be concluded that the integrated pulsar time stability obtained based on the timing residual data processing algorithm provided in this embodiment is generally 1 order of magnitude higher than that of the single pulsar.
The embodiment of the invention provides a comprehensive pulsar time determination method based on timing residual errors, which is characterized by sequentially preprocessing and filtering the initial timing residual error of each screened optimal pulsar to obtain a corresponding smooth timing residual error, and performing equidistant downsampling on the smooth timing residual error and the initial error of each optimal pulsar to determine the comprehensive pulsar time stability according to the downsampled timing residual error, the downsampled initial error and the julian days of reference pulsars. Compared with the prior art, the method for processing the pulsar timing residual errors based on preprocessing, vondrak filtering and down sampling is adopted, meanwhile, a classic weighted average algorithm is used for establishing comprehensive pulsar timing for the timing residual errors after 8 optimal pulsars are processed, the technical effects that the stability of 22yr is improved by 0.9 orders of magnitude compared with that of a single pulsar with the highest stability, and the average level of the stability of the single pulsar under the time scale is improved by more than 1 order of magnitude are achieved, and the method has important practical significance for pulsar timing.
It should be noted that, the sequence numbers of the above processes do not mean the execution sequence, and the execution sequence of each process should be determined by the function and the inherent logic of each process, and should not limit the implementation process of the embodiment of the present application.
In one embodiment, as shown in fig. 7, an embodiment of the present invention provides a timing residual-based integrated pulsar time determination system, including:
the optimal pulsar obtaining module 101 is configured to select at least two optimal pulsars according to a preset optimal screening condition, and obtain an initial timing residual error and an initial error of each optimal pulsar;
the pulsar data processing module 102 is configured to sequentially perform preprocessing and filtering on the initial timing residual error of each optimal pulsar to obtain a corresponding smooth timing residual error; according to a pre-selected reference julian day, performing equidistant downsampling on the smooth timing residual error and the initial error of each optimal pulsar to obtain corresponding downsampled timing residual error and downsampled initial error; the system is also used for obtaining the stability of each optimal pulsar according to the timing residual after the down-sampling and the initial error after the down-sampling;
the timing residual weighting module 103 is used for obtaining a comprehensive weighting residual and a comprehensive weighting error according to the stability of each optimal pulsar;
and a comprehensive pulsar-time determining module 104, configured to obtain a comprehensive pulsar-time stability according to the comprehensive weighted residual, the comprehensive weighted error, and the reference julian day.
For specific limitations of a timing residual based integrated pulsar time determination system, reference may be made to the above limitations of a timing residual based integrated pulsar time determination method, which are not described herein again. Those of ordinary skill in the art will appreciate that the various modules and steps described in connection with the embodiments disclosed herein may be implemented in hardware, software, or a combination of both. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
The embodiment of the invention provides a comprehensive pulsar time determination system based on timing residual errors, wherein a pulsar data processing module of the system adopts a pulsar timing residual error processing mode based on preprocessing, vondrak filtering and down sampling, and a timing residual error weighting module processes the timing residual errors and errors after optimal pulsar processing through a weighted average algorithm, so that the comprehensive pulsar time stability is determined. Compared with the prior art, the method and the device can effectively guide the subsequent positioning navigation time service, improve the reliability and the interpretability of pulsar timing, and have the advantages of wide application range, strong practicability, high navigation efficiency and the like.
FIG. 8 is a block diagram of a computer device including a memory, a processor, and a transceiver coupled via a bus according to an embodiment of the invention; the memory is used to store a set of computer program instructions and data and may transmit the stored data to the processor, which may execute the program instructions stored by the memory to perform the steps of the above-described method.
Wherein the memory may comprise volatile memory or non-volatile memory, or may comprise both volatile and non-volatile memory; the processor may be a central processing unit, a microprocessor, an application specific integrated circuit, a programmable logic device, or a combination thereof. By way of example, and not limitation, the programmable logic devices described above may be complex programmable logic devices, field programmable gate arrays, general array logic, or any combination thereof.
In addition, the memory may be a physically separate unit or may be integrated with the processor.
It will be appreciated by those of ordinary skill in the art that the architecture shown in fig. 8 is a block diagram of only a portion of the architecture associated with the present solution and is not intended to limit the computing devices to which the present solution may be applied, and that a particular computing device may include more or less components than those shown, or may combine certain components, or have the same arrangement of components.
In one embodiment, the present invention provides a computer readable storage medium, on which a computer program is stored, which when executed by a processor implements the steps of the above-described method.
According to the comprehensive pulsar time determining method and system based on the timing residual errors, pulsar timing residual error processing based on preprocessing, vondrak filtering and down sampling is achieved, meanwhile, a classic weighted average pulsar time algorithm is utilized, comprehensive pulsar time stability with high reliability is obtained, and the method and system can be used for providing data support for pulsar navigation.
In the above embodiments, all or part of the implementation may be realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the invention to be performed in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (e.g., coaxial cable, fiber optic, digital subscriber line) or wirelessly (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that includes one or more available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., SSD), among others.
Those skilled in the art will appreciate that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and the computer program can include the processes of the embodiments of the methods described above when executed.
The above-mentioned embodiments only express some preferred embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for those skilled in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present application. Therefore, the protection scope of the present patent shall be subject to the protection scope of the claims.
Claims (10)
1. A comprehensive pulsar time determination method based on timing residual errors is characterized by comprising the following steps:
selecting at least two optimal pulsar according to preset optimal screening conditions, and acquiring an initial timing residual error and an initial error of each optimal pulsar;
sequentially preprocessing and filtering the initial timing residual error of each optimal pulsar to obtain a corresponding smooth timing residual error;
selecting a reference pulsar, and performing equidistant downsampling on the smooth timing residual error and the initial error of each optimal pulsar according to the number of observation points of the reference pulsar to obtain a corresponding downsampled timing residual error and a corresponding downsampled initial error;
obtaining the stability of each optimal pulsar according to the timing residual after the down-sampling and the initial error after the down-sampling;
obtaining a comprehensive weighted residual error and a comprehensive weighted error according to the stability of each optimal pulsar;
and obtaining the comprehensive pulsar time stability according to the comprehensive weighted residual error, the comprehensive weighted error and the julian day of the reference pulsar.
2. The method of claim 1, wherein the predetermined optimal selection condition comprises:
the optimal pulsar is a millisecond pulsar, the observation time span of the optimal pulsar needs to meet a preset observation time span threshold value, and the number of observation points needs to meet a preset observation point threshold value.
3. The method of claim 1, wherein the step of preprocessing and filtering the initial timing residuals of each optimal pulsar in sequence to obtain corresponding smoothed timing residuals comprises:
performing gross error point extraction on the initial timing residual error of each optimal pulsar by using an absolute median deviation method;
carrying out zero setting processing on the gross error point of each optimal pulsar, and carrying out interpolation processing on the gross error point by utilizing a segmented cubic Hermite interpolation method to obtain a preprocessed initial timing residual error;
and performing filtering and noise reduction treatment on the preprocessed initial timing residual error by using Vondrak filtering to obtain a smooth timing residual error of each optimal pulsar.
4. The method of claim 1, wherein the integrated weighted residual and the integrated weighted error are calculated by the following equations:
wherein the content of the first and second substances,
in the formula res General (1) Represents the integrated weighted residual; res is i ' represents the timing residual after the down-sampling of the ith optimal pulsar; err (r) General assembly Representing the composite weighted error; err (r) i ' represents the initial error after the down-sampling of the ith optimal pulsar; w is a i Representing the weight of the ith optimal pulsar; sigma zi And the stability of the ith optimal pulsar is shown.
5. The method of claim 1, wherein the integrated pulsar-time stability level is calculated by the formula:
in the formula, σ General assembly (τ) represents integrated pulsar time stability; τ represents a time scale; c. C 3 Representing a cubic polynomial coefficient; res is General assembly Representing the integrated weighted residual; x (MJD 3) represents a cubic polynomial fitting function; MJD3 represents the julian day of the reference pulsar; err (r) General assembly Representing the integrated weighted error.
6. The method of claim 1, wherein the step of selecting a reference pulsar comprises: and screening all the optimal pulsar according to a preset reference screening condition to obtain a reference pulsar, and taking the julian day of the reference pulsar as a reference julian day.
7. The method as claimed in claim 1, wherein the predetermined reference screening condition comprises: and selecting the optimal pulsar with the least observation points as a reference pulsar.
8. A system for integrated pulsar-time determination based on timing residuals, said system comprising:
the optimal pulsar obtaining module is used for selecting at least two optimal pulsars according to preset optimal screening conditions and obtaining an initial timing residual error and an initial error of each optimal pulsar;
the pulsar data processing module is used for sequentially preprocessing and filtering the initial timing residual error of each optimal pulsar to obtain a corresponding smooth timing residual error; the method is also used for selecting a reference pulsar and performing equidistant downsampling on the smooth timing residual error and the initial error of each optimal pulsar according to the number of observation points of the reference pulsar to obtain a corresponding downsampled timing residual error and a downsampled initial error; obtaining the stability of each optimal pulsar according to the timing residual after the down-sampling and the initial error after the down-sampling;
the timing residual weighting module is used for obtaining comprehensive weighting residual and comprehensive weighting error according to the stability of each optimal pulsar;
and the comprehensive pulsar time determining module is used for obtaining the comprehensive pulsar time stability according to the comprehensive weighting residual error, the comprehensive weighting error and the julian day of the reference pulsar.
9. A computer device, characterized by: comprising a processor and a memory, the processor being connected to the memory, the memory being adapted to store a computer program, the processor being adapted to execute the computer program stored in the memory to cause the computer device to perform the method of any of claims 1 to 7.
10. A computer-readable storage medium characterized by: the computer-readable storage medium has stored thereon a computer program which, when executed, implements the method of any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211514638.8A CN115808867A (en) | 2022-11-30 | 2022-11-30 | Comprehensive pulsar time determination method and system based on timing residual error |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211514638.8A CN115808867A (en) | 2022-11-30 | 2022-11-30 | Comprehensive pulsar time determination method and system based on timing residual error |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115808867A true CN115808867A (en) | 2023-03-17 |
Family
ID=85484588
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211514638.8A Pending CN115808867A (en) | 2022-11-30 | 2022-11-30 | Comprehensive pulsar time determination method and system based on timing residual error |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115808867A (en) |
-
2022
- 2022-11-30 CN CN202211514638.8A patent/CN115808867A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102098133B (en) | Soft decoding for quantizied channel | |
| CN110008080B (en) | Business index anomaly detection method and device based on time sequence and electronic equipment | |
| CN111458746B (en) | Tunnel microseismic waveform arrival time picking method based on U-Net neural network | |
| CN101860344A (en) | Construction method of frequency-selecting filter and construction method for realizing FIR-type and IIR-type filters by adopting same | |
| CN110517154A (en) | Data model training method, system and computer equipment | |
| CN114240779B (en) | Point cloud denoising method, device, equipment and storage medium | |
| CN113495913B (en) | Air quality data missing value interpolation method and device | |
| CN107677290B (en) | Testing method and device for precision evaluation of inertial navigation system | |
| CN115808867A (en) | Comprehensive pulsar time determination method and system based on timing residual error | |
| US20030149560A1 (en) | Pitch extraction methods and systems for speech coding using interpolation techniques | |
| CN109736793B (en) | Method and equipment for evaluating pore structure of reservoir | |
| Rowlands et al. | Denoising of spectra with no user input: a spline‐smoothing algorithm | |
| CN108596383B (en) | Reservoir classification method and device | |
| CN114114421B (en) | Deep learning-based guided self-learning seismic data denoising method and device | |
| CN112882907B (en) | User state determination method and device based on log data | |
| CN112363243A (en) | Method, device, computer equipment and medium for predicting high-quality reservoir of shale oil | |
| US10671624B2 (en) | Parallel filtering of large time series of data for filters having recursive dependencies | |
| CN111985163B (en) | Rubidium clock life prediction method and device | |
| CN115541021A (en) | Method for locating characteristic peak of Raman spectrum, electronic device and storage medium | |
| CN115685340A (en) | Method and device for improving seismic characterization precision of thin-layer structure | |
| CN114114881B (en) | Pulsar timing performance optimization method and system | |
| CN113608261B (en) | Diffracted wave imaging method and device and electronic equipment | |
| CN107861918B (en) | M-sparse algorithm-based nuclear magnetic resonance echo data inversion method and device | |
| CN112712855A (en) | Joint training-based clustering method for gene microarray containing deletion value | |
| CN113590952B (en) | Data center construction method and system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |