A method and apparatus for calculating the systematic difference of space-based directional observation data

Abstract

This invention discloses a method and apparatus for calculating the systematic difference of space-based directional observation data. The method includes: acquiring a set of stellar angular distance measurement data; processing precise ephemeris data of BeiDou satellites obtained from the MGEX system to obtain a set of true stellar angular distance values; calculating the systematic difference of the observation data using the set of stellar angular distance measurement data and the set of true stellar angular distance values; performing error calculation processing on the systematic difference of the observation data to obtain systematic difference characteristics; and evaluating the systematic difference characteristics to obtain systematic difference accuracy evaluation information. Using the technical solution provided in this application, the influence of different error sources on space-based directional observation data can be effectively separated and corrected, improving the robustness and adaptability of the calculation model.

Description

Technical Field

[0001] This invention relates to the field of satellite navigation technology, specifically to a method and apparatus for calculating the systematic difference of space-based directional observation data. Background Technology

[0002] Space-based orientation observation differs from traditional navigation systems that rely on ground stations to establish satellite orbit observation and orientation observation capabilities. It obtains the relative direction information of target satellites and background stars through high-precision star sensors, providing accurate inertial orientation reference for navigation satellites. This reduces dependence on ground stations, enhances the independent operation capability of the navigation system, and has the advantages of space autonomy, high dynamic coverage, and continuous observation.

[0003] Current research on space-based orientation observation technology largely focuses on algorithm verification and data processing, demonstrating preliminary feasibility in supporting autonomous orbit determination of navigation satellites. However, this research is mainly confined to the simulation verification stage and has not yet delved into the systematic errors commonly found in space-based orientation observation data in practical applications. Systematic errors, such as constant deviation, linear drift, and periodic errors, are often caused by a combination of factors including equipment characteristics, environmental changes, and observation conditions, requiring effective modeling for correction. Therefore, in-depth research into the systematic error characteristics of space-based orientation observation data and the development of targeted modeling and solution methods are crucial for the practical application of space-based orientation measurement. Summary of the Invention

[0004] To address the typical systematic errors in current space-based orientation observation data—constant deviation, linear error, and periodic error—this invention proposes a method for modeling and solving systematic errors in observation data, oriented towards these three types of error characteristics. Through in-depth modeling and precise correction of systematic errors, this method effectively improves the accuracy of navigation satellite orbit calculation, particularly demonstrating significant advantages in orbital plane orientation parameter estimation. It provides a solution for the field of systematic error solving in observation data and offers theoretical support and application basis for the further development of future navigation and measurement technologies.

[0005] To achieve the above objectives, a first aspect of the present invention discloses a method for calculating the systematic difference of space-based directional observation data, the method comprising:

[0006] S1. Obtain a set of stellar angular distance measurement data; the stellar angular distance measurement data includes the relative right ascension and relative declination observation values ​​between the observing satellite and the observed satellite; the observing satellite is a BeiDou IGSO satellite, and the observed satellite is a BeiDou MEO satellite; the stellar angular distance measurement data set includes the relative right ascension and relative declination observation values ​​with an observation duration of not less than 24 hours;

[0007] S2. Calculate and process the precise ephemeris of the BeiDou satellites to obtain a set of true values ​​for stellar angular distances; the true values ​​for stellar angular distances include true values ​​for relative right ascension and relative declination; the precise ephemeris of the BeiDou satellites is obtained from the MGEX system.

[0008] S3. Process the set of stellar angular distance measurement data and the set of stellar angular distance true values ​​to obtain the systematic difference of the observation data;

[0009] S4. Perform error calculation on the systematic difference of the observed data to obtain the systematic difference characteristics; the systematic difference characteristics include constant characteristics, linear characteristics, and periodic characteristics;

[0010] S5. The system difference characteristics are evaluated to obtain system difference accuracy evaluation information.

[0011] As an optional implementation, in the first aspect of the present invention, acquiring the set of stellar angular distance measurement data includes:

[0012] S11. Establish a staring link between the observation satellite and the observed satellite; the observation satellite includes 3 BeiDou IGSO satellites; the observed satellite includes 28 MEO satellites, distributed in 3 orbital planes, with each orbit corresponding to 3 BeiDou IGSO satellites; each BeiDou IGSO satellite establishes a fixed observation link with one visible MEO satellite in the observed orbit, and when the visible MEO satellite becomes invisible, switch to other visible MEO satellites in the same orbital plane;

[0013] S12. Within a preset observation period, at a preset observation interval, continuous observation is conducted using BeiDou IGSO satellites to obtain a set of stellar angular distance measurement data; each observation data includes 3 stellar angular distance measurement data, and each BeiDou IGSO satellite acquires 1 stellar angular distance measurement data; optionally, the preset observation period is not less than 1 day, and the preset observation interval is 15 minutes.

[0014] As an optional implementation, in the first aspect of the present invention, the calculation and processing of the precise ephemeris of the BeiDou satellite to obtain the true set of stellar angular distances includes:

[0015] S21. Obtain the precise ephemeris of the BeiDou satellite from the MGEX system; the precise ephemeris of the BeiDou satellite corresponds to the observation time of the star angular distance measurement data set; it should be noted that the precise ephemeris of the BeiDou satellite obtained from the MGEX system refers to the precise ephemeris of the BeiDou satellite released by the Multimode GNSS Experimental Tracking Network International Organization, which is public information.

[0016] S22. Using the true value calculation model of stellar angular distance, the precise ephemeris of the Beidou satellite is processed to obtain the true value set of stellar angular distance;

[0017] The true value calculation model expression for stellar angular distance is as follows:

[0018]

[0019] In the formula, and These are the true values ​​of the relative right ascension and relative declination between the observed satellite i and the observed satellite j, respectively. and The position vectors of satellite i and observed satellite j in the inertial coordinate system are observed respectively.

[0020] As an optional implementation, in the first aspect of the present invention, the processing of the stellar angular distance measurement data set and the stellar angular distance true value set to obtain the observation data systematic difference includes:

[0021] S31. Construct an observation model based on stellar angular distance measurement data and true stellar angular distance values;

[0022] The observation model is represented as follows:

[0023]

[0024] In the formula, and These are the relative right ascension and relative declination observations, respectively. and These represent the true relative right ascension and true relative declination between IGSO observation satellite i and observed MEO satellite j in the celestial coordinate system. and The relative right ascension error and relative declination error of the BeiDou IGSO satellite. and The relative right ascension error and relative declination error of the BeiDou MEO satellite are given; both of these errors include system error and Gaussian white noise.

[0025] S32. Apply error constraints to the observation model;

[0026] S33. Based on the error constraint, the observation model is used to process the stellar angular distance measurement data set to generate observation error values; the observation error values ​​include constant observation deviation values, linear observation error values, and periodic observation error values;

[0027] S34. Based on the observation error value, the observation model is used to solve the set of stellar angular distance measurement data and the set of true stellar angular distance values ​​to obtain the observation data systematic error; the observation data systematic error includes the relative right ascension systematic error and the relative declination systematic error.

[0028] As an optional implementation, in the first aspect of the present invention, the error constraint on the observation model specifically includes:

[0029] S321. The relative difference in right ascension and relative difference in declination must satisfy the following conditions:

[0030]

[0031] In the formula, p represents the satellite number, and N represents the number of BeiDou satellites used for space-based orientation measurement; and The relative right ascension error and relative declination error of satellite p; the and There are three forms of manifestation: constant deviation, linear error, and periodic error, as described in S322, S323, and S324.

[0032] S322, The constant deviation of the observation model is:

[0033]

[0034] in, Indicates the satellite's relative declination constant deviation. This represents the satellite's relative declination constant deviation, and scid represents the satellite number; JudP(scid) is a parity function to determine whether scid is odd or even. When scid is odd, JudP(scid) is -1, and when scid is even, JudP(scid) is 1. and These are Gaussian white noises with respect to relative right ascension and relative declination, respectively, under constant deviation.

[0035] S323, The linearity error of the observation model is:

[0036]

[0037] In the formula, Indicates the relative right ascension linearity error. This represents the linear error relative to declination, where t is the observation time; and These are Gaussian white noises with respect to relative right ascension and relative declination, respectively, under linear error conditions.

[0038] S324, The periodic error of the observation model is:

[0039]

[0040] In the formula, This indicates the periodicity error relative to right ascension. This indicates the periodicity error relative to declination. and These are Gaussian white noises with respect to relative right ascension and relative declination, respectively, under periodic deviation.

[0041] As an optional implementation, in the first aspect of the present invention, the observation data systematic error is obtained by solving the set of stellar angular distance measurement data and the set of true stellar angular distance values ​​using the observation model based on the observation error value.

[0042] S341. Obtain stellar angular distance measurement data for any observation epoch k from the set of stellar angular distance measurement data.

[0043] S342. Obtain the true value of stellar angular distance corresponding to any observation epoch k from the set of true values ​​of stellar angular distance;

[0044] S343. Based on the aforementioned observation model, using the least squares algorithm, calculate the stellar angular distance measurement data and the true value of the stellar angular distance for any observation epoch k, and obtain the relative right ascension systematic difference between the observed satellite and the observed satellite at that observation epoch k. Relative declination system difference

[0045] S344. Repeat steps S341 to S343 to calculate the relative right ascension systematic difference and relative declination systematic difference for each satellite corresponding to all observation epochs, and obtain the systematic difference of the observation data.

[0046] As an optional implementation, in the first aspect of the present invention, the step of performing error calculation processing on the systematic difference of the observation data to obtain the systematic difference characteristics includes:

[0047] S41. Using the constant deviation solution model, the systematic error of the observation data is processed to obtain the constant characteristics of each satellite;

[0048] The constant deviation calculation model is expressed as follows:

[0049]

[0050] In the formula, i represents the satellite number. The relative equatorial constant characteristic of satellite i is represented by M, which represents the number of epochs in which the systematic difference of satellite i's observation data is collected within the observation period. This represents the difference in right ascension relative to the system at the m-th epoch of satellite i; This indicates the relative latitude and longitude characteristics of satellite i. This represents the difference in latitude and longitude relative to the latitude and longitude system at the m-th epoch of satellite i;

[0051] S42. Using the systematic difference of the observation data, and using a preset linear error model of the observation values, the linear characteristics of each satellite are obtained by fitting and solving the data using the least squares method.

[0052] The preset linear error model for the observed values ​​is expressed as follows:

[0053]

[0054] In the formula, i represents the satellite number. This indicates the linearity of the relative right ascension of satellite i. This represents the relative latitude and longitude linearity of satellite i, where t represents the observation time, and a... i b i c i d i These represent the linear parameters of satellite i, respectively.

[0055] S43. Using the systematic difference of the observation data, solve the preset periodic error model of the observation values ​​to obtain the periodic characteristics of each satellite.

[0056] The preset periodic error model of the observed values ​​is expressed as follows:

[0057]

[0058] In the formula, i represents the satellite number. This indicates the periodicity of the relative right ascension of satellite i. The relative latitude and longitude periodicity of satellite i is represented by t, which represents the observation time, and e is the periodicity of ... i f i g i h i These represent the periodic parameters of satellite i;

[0059] As an optional implementation, in the first aspect of the present invention, processing the system difference characteristics to obtain system difference accuracy evaluation information includes:

[0060] S51. Evaluate the constant characteristics in the system difference characteristics to obtain the constant system difference solution accuracy, specifically:

[0061] S511. Based on the system difference characteristics, obtain the constant characteristics of satellite i;

[0062] S512. Using the constant deviation evaluation model, the constant characteristics of satellite i are evaluated and calculated to obtain the constant systematic difference calculation accuracy of satellite i; the constant systematic difference calculation accuracy includes the relative declination and latitude systematic difference calculation accuracy and the relative declination constant systematic difference calculation accuracy.

[0063] The constant deviation evaluation model is expressed as follows:

[0064]

[0065] In the formula, This indicates the accuracy of the relative ascension and latitude systematic difference solution for satellite i. This indicates the accuracy of the systematic difference solution for the relative declination constant of satellite i. This represents the relative equatorial constant characteristic of satellite i. The relative latitude constant characteristic of satellite i is represented by scid, which represents the satellite number; JudP(scid) is a parity function to determine whether scid is odd or even. When scid is odd, JudP(scid) is -1, and when scid is even, JudP(scid) is 1.

[0066] S513. Repeat S511 to S512 until the constant system difference calculation accuracy of all satellites is completed.

[0067] S52. Evaluate the linearity of the system difference characteristics to obtain the linear system difference solution accuracy, specifically:

[0068] S521. Based on the system difference characteristics, obtain the linear parameters of satellite i;

[0069] S522. Using the linear system difference evaluation model, the linear parameters of satellite i are evaluated and calculated to obtain the linear system difference solution accuracy of satellite i.

[0070] The linear systematic error evaluation model is expressed as:

[0071]

[0072] In the formula, The linear systematic error solution accuracy of satellite i is represented by , where a, b, c, and d represent the linear parameters of satellite i, and scid represents the satellite number. JudP(scid) is a parity function for determining whether scid is odd or even. When scid is odd, JudP(scid) is -1, and when scid is even, JudP(scid) is 1.

[0073] S523. Repeat S521 to S522 until the linear system difference calculation accuracy of all satellites is completed.

[0074] S53. Evaluate and process the periodic characteristics in the system difference characteristics to obtain the accuracy of the periodic system difference solution, specifically:

[0075] S531. Based on the aforementioned system difference characteristics, obtain the periodic parameters of satellite i;

[0076] S532. Using the periodic systematic difference evaluation model, the periodic parameters of satellite i are evaluated and calculated to obtain the periodic systematic difference solution accuracy of satellite i.

[0077] The periodic systematic error assessment model is expressed as:

[0078]

[0079] In the formula, The periodic systematic difference calculation accuracy of satellite i is represented by , e, f, g, and h represent the periodic parameters of satellite i, and scid represents the satellite number; JudP(scid) is a parity function to determine whether scid is odd or even. When scid is odd, JudP(scid) is -1, and when scid is even, JudP(scid) is 1.

[0080] S533, repeat S531 to S532 until the periodic systematic difference calculation accuracy of all satellites is completed.

[0081] S54. The accuracy of the constant systematic difference calculation, the accuracy of the linear systematic difference calculation, and the accuracy of the periodic systematic difference calculation are comprehensively processed to obtain systematic difference accuracy evaluation information.

[0082] The second aspect of this invention discloses a systematic difference calculation device for space-based directional observation data, employing the systematic difference calculation method for space-based directional observation data disclosed in the first aspect of this invention. The device includes:

[0083] The stellar angular distance measurement data acquisition module is used to acquire a set of stellar angular distance measurement data; the stellar angular distance measurement data includes the relative right ascension and relative declination observation values ​​between the observing satellite and the observed satellite; the observing satellite is a BeiDou IGSO satellite, and the observed satellite is a BeiDou MEO satellite;

[0084] The stellar angular distance truth value calculation module is used to calculate and process the precise ephemeris of BeiDou satellites to obtain a set of stellar angular distance truth values; the stellar angular distance truth values ​​include relative right ascension truth values ​​and relative declination truth values; the precise ephemeris of BeiDou satellites is obtained from the MGEX system;

[0085] The observation data systematic difference calculation module is used to process the set of stellar angular distance measurement data and the set of true stellar angular distance values ​​to obtain the observation data systematic difference;

[0086] The systematic error characteristic analysis module is used to perform error calculation on the systematic error of the observed data to obtain the systematic error characteristics; the systematic error characteristics include constant characteristics, linear characteristics, and periodic characteristics;

[0087] The evaluation module is used to evaluate the system difference characteristics and obtain system difference accuracy evaluation information.

[0088] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0089] The systematic error calculation method and apparatus for space-based directional observation data disclosed in this invention are designed for modeling and calculating systematic errors of space-based directional observation data with three types of error characteristics, and have the following technical advantages:

[0090] (1) Modeling and solving for multiple types of error characteristics. This invention incorporates three types of error characteristics—constant deviation, linear error, and periodic error—into a unified modeling framework, which can effectively separate and correct the influence of different error sources on space-based orientation observation data, and improve the robustness and adaptability of the solution model.

[0091] (2) Accuracy verification is performed using actual simulation data. The technical solution of this invention is based on the actual on-orbit state of Beidou satellites. It uses the actual simulation system difference as a benchmark for modeling and verification to ensure the practical applicability and high accuracy and reliability of the model. At the same time, the performance of the solution algorithm is optimized by evaluating the accuracy of the observation data system difference. Attached Figure Description

[0092] Figure 1 This is a schematic diagram of a method for calculating the systematic difference of space-based directional observation data disclosed in an embodiment of the present invention;

[0093] Figure 2 This is a schematic diagram of a system difference data processing procedure for space-based directional observation data disclosed in an embodiment of the present invention;

[0094] Figure 3 This is a schematic diagram of a space-based directional observation data system difference calculation device disclosed in an embodiment of the present invention;

[0095] Figure 4 This is a schematic diagram of another space-based directional observation data system difference calculation device disclosed in an embodiment of the present invention. Detailed Implementation

[0096] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0097] Example 1

[0098] Please see Figure 1 , 2 . Figure 1This is a schematic diagram of a method for calculating the systematic difference of space-based directional observation data disclosed in an embodiment of the present invention. Figure 2 This is a schematic diagram of a BeiDou satellite observation data system difference data processing process disclosed in an embodiment of the present invention; wherein, the space-based directional observation data system difference calculation method described in this application is applied in a management system, such as a local server or cloud server for management, etc., and the embodiments of the present invention are not limited thereto.

[0099] like Figure 1 As shown, the systematic difference calculation method for space-based directional observation data disclosed in this embodiment of the invention includes:

[0100] S1. Obtain a set of stellar angular distance measurement data; the stellar angular distance measurement data includes the relative right ascension and relative declination observation values ​​between the observing satellite and the observed satellite; the observing satellite is a BeiDou IGSO satellite, and the observed satellite is a BeiDou MEO satellite; the stellar angular distance measurement data set includes the relative right ascension and relative declination observation values ​​with an observation duration of not less than 24 hours;

[0101] S2. Calculate and process the precise ephemeris of the BeiDou satellites to obtain a set of true values ​​for stellar angular distances; the true values ​​for stellar angular distances include true values ​​for relative right ascension and relative declination; the precise ephemeris of the BeiDou satellites is obtained from the MGEX system.

[0102] S3. Process the set of stellar angular distance measurement data and the set of stellar angular distance true values ​​to obtain the systematic difference of the observation data;

[0103] S4. Perform error calculation on the systematic difference of the observed data to obtain the systematic difference characteristics; the systematic difference characteristics include constant characteristics, linear characteristics, and periodic characteristics;

[0104] S5. The system difference characteristics are evaluated to obtain system difference accuracy evaluation information.

[0105] In another optional embodiment, acquiring the stellar angular distance measurement data set includes:

[0106] S11. Establish a staring link between the observation satellite and the observed satellite; the observation satellite includes 3 BeiDou IGSO satellites; the observed satellite includes 28 MEO satellites, distributed in 3 orbital planes, with each orbit corresponding to 3 BeiDou IGSO satellites; each BeiDou IGSO satellite establishes a fixed observation link with one visible MEO satellite in the observed orbit, and when the visible MEO satellite becomes invisible, switch to other visible MEO satellites in the same orbital plane;

[0107] S12. Within a preset observation period, at a preset observation interval, continuous observation is conducted using BeiDou IGSO satellites to obtain a set of stellar angular distance measurement data; each observation data includes 3 stellar angular distance measurement data, and each BeiDou IGSO satellite obtains 1 stellar angular distance measurement data; optionally, the preset observation period is not less than 1 day, and the preset observation interval is 15 minutes.

[0108] In another optional embodiment, the calculation and processing of the precise ephemeris of the BeiDou satellite to obtain the true set of stellar angular distances includes:

[0109] S21. Obtain the precise ephemeris of the BeiDou satellite from the MGEX system; the precise ephemeris of the BeiDou satellite corresponds to the observation time of the set of stellar angular distance measurement data.

[0110] S22. Using the true value calculation model of stellar angular distance, the precise ephemeris of the Beidou satellite is processed to obtain the true value set of stellar angular distance;

[0111] The true value calculation model expression for stellar angular distance is as follows:

[0112]

[0113] In the formula, and These are the true values ​​of the relative right ascension and relative declination between the observed satellite i and the observed satellite j, respectively. and The position vectors of satellite i and observed satellite j in the inertial coordinate system are observed respectively.

[0114] In another optional embodiment, the processing of the stellar angular distance measurement data set and the stellar angular distance true value set to obtain the observation data systematic difference includes:

[0115] S31. Construct an observation model based on stellar angular distance measurement data and true stellar angular distance values;

[0116] The observation model is represented as follows:

[0117]

[0118] In the formula, and These are the relative right ascension and relative declination observations, respectively. and These represent the true relative right ascension and true relative declination between IGSO observation satellite i and observed MEO satellite j in the celestial coordinate system. and The relative right ascension error and relative declination error of the BeiDou IGSO satellite. and The relative right ascension error and relative declination error of the BeiDou MEO satellite are given; both of these errors include system error and Gaussian white noise.

[0119] S32. Apply error constraints to the observation model;

[0120] S33. Based on the error constraint, the observation model is used to process the stellar angular distance measurement data set to generate observation error values; the observation error values ​​include constant observation deviation values, linear observation error values, and periodic observation error values;

[0121] S34. Based on the observation error value, the observation model is used to solve the set of stellar angular distance measurement data and the set of true stellar angular distance values ​​to obtain the observation data systematic error; the observation data systematic error includes the relative right ascension systematic error and the relative declination systematic error.

[0122] In yet another optional embodiment, the error constraint on the observation model specifically includes:

[0123] S321. The relative difference in right ascension and relative difference in declination must satisfy the following conditions:

[0124]

[0125] In the formula, p represents the satellite number, and N represents the number of BeiDou satellites used for space-based orientation measurement; and The relative right ascension error and relative declination error of satellite p; the and There are three forms of manifestation: constant deviation, linear error, and periodic error, as described in S322, S323, and S324.

[0126] S322, The constant deviation of the observation model is:

[0127]

[0128] in, Indicates the satellite's relative declination constant deviation. This represents the satellite's relative declination constant deviation, and scid represents the satellite number; JudP(scid) is a parity function to determine whether scid is odd or even. When scid is odd, JudP(scid) is -1, and when scid is even, JudP(scid) is 1. and These are Gaussian white noises with respect to relative right ascension and relative declination, respectively, under constant deviation.

[0129] S323, The linearity error of the observation model is:

[0130]

[0131] In the formula, Indicates the relative right ascension linearity error. This represents the linear error relative to declination, where t is the observation time; and These are Gaussian white noises with respect to relative right ascension and relative declination, respectively, under linear error conditions.

[0132] S324, The periodic error of the observation model is:

[0133]

[0134] In the formula, This indicates the periodicity error relative to right ascension. This indicates the periodicity error relative to declination. and These are Gaussian white noises with respect to relative right ascension and relative declination under periodic deviation, respectively.

[0135] In another optional embodiment, the observation model is used to solve the set of stellar angular distance measurement data and the set of true stellar angular distance values ​​based on the observation error value to obtain the systematic error of the observation data.

[0136] S341. Obtain stellar angular distance measurement data for any observation epoch k from the set of stellar angular distance measurement data.

[0137] S342. Obtain the true value of stellar angular distance corresponding to any observation epoch k from the set of true values ​​of stellar angular distance;

[0138] S343. Based on the aforementioned observation model, using the least squares algorithm, calculate the stellar angular distance measurement data and the true value of the stellar angular distance for any observation epoch k, and obtain the relative right ascension systematic difference between the observed satellite and the observed satellite at that observation epoch k. Relative declination system difference

[0139] S344. Repeat steps S341 to S343 to calculate the relative right ascension systematic difference and relative declination systematic difference for each satellite corresponding to all observation epochs, and obtain the systematic difference of the observation data.

[0140] In yet another optional embodiment, the step of performing error calculation on the systematic error of the observed data to obtain the systematic error characteristics includes:

[0141] S41. Using the constant deviation solution model, the systematic error of the observation data is processed to obtain the constant characteristics of each satellite;

[0142] The constant deviation calculation model is expressed as follows:

[0143]

[0144] In the formula, i represents the satellite number. The relative equatorial constant characteristic of satellite i is represented by M, which represents the number of epochs in which the systematic difference of satellite i's observation data is collected within the observation period. This represents the difference in right ascension relative to the system at the m-th epoch of satellite i; This indicates the relative latitude and longitude characteristics of satellite i. This represents the difference in latitude and longitude relative to the latitude and longitude system at the m-th epoch of satellite i;

[0145] S42. Using the systematic difference of the observation data, and using a preset linear error model of the observation values, the linear characteristics of each satellite are obtained by fitting and solving the data using the least squares method.

[0146] The preset linear error model for the observed values ​​is expressed as follows:

[0147]

[0148] In the formula, i represents the satellite number. This indicates the linearity of the relative right ascension of satellite i. This represents the relative latitude and longitude linearity of satellite i, where t represents the observation time, and a... i b i c i d i These represent the linear parameters of satellite i, respectively.

[0149] It should be noted that the solution process uses the systematic difference of satellite i's observation data within the observation period. As observations, the linear coefficients a, b, c, and d are obtained by fitting using the least squares method;

[0150] S43. Using the systematic difference of the observation data, solve the preset periodic error model of the observation values ​​to obtain the periodic characteristics of each satellite.

[0151] The preset periodic error model of the observed values ​​is expressed as follows:

[0152]

[0153] In the formula, i represents the satellite number. This indicates the periodicity of the relative right ascension of satellite i. The relative latitude and longitude periodicity of satellite i is represented by t, which represents the observation time, and e is the periodicity of ... i f i g i h iThese represent the periodic parameters of satellite i;

[0154] It should be noted that the calculation process uses the systematic difference of satellite i's observation data within the observation period. As observables, the periodic coefficients e, f, g, and h are obtained by fitting using the least squares method.

[0155] In yet another optional embodiment, processing the systematic difference characteristics to obtain systematic difference accuracy assessment information includes:

[0156] S51. Evaluate the constant characteristics in the system difference characteristics to obtain the constant system difference solution accuracy, specifically:

[0157] S511. Based on the system difference characteristics, obtain the constant characteristics of satellite i;

[0158] S512. Using the constant deviation evaluation model, the constant characteristics of satellite i are evaluated and calculated to obtain the constant systematic difference calculation accuracy of satellite i; the constant systematic difference calculation accuracy includes the relative declination and latitude systematic difference calculation accuracy and the relative declination constant systematic difference calculation accuracy.

[0159] The constant deviation evaluation model is expressed as follows:

[0160]

[0161] In the formula, This indicates the accuracy of the relative ascension and latitude systematic difference solution for satellite i. This indicates the accuracy of the systematic difference solution for the relative declination constant of satellite i. This represents the relative equatorial constant characteristic of satellite i. The relative latitude constant characteristic of satellite i is represented by scid, which represents the satellite number; JudP(scid) is a parity function to determine whether scid is odd or even. When scid is odd, JudP(scid) is -1, and when scid is even, JudP(scid) is 1.

[0162] S513. Repeat S511 to S512 until the constant system difference calculation accuracy of all satellites is completed.

[0163] S52. Evaluate the linearity of the system difference characteristics to obtain the linear system difference solution accuracy, specifically:

[0164] S521. Based on the system difference characteristics, obtain the linear parameters of satellite i;

[0165] S522. Using the linear system difference evaluation model, the linear parameters of satellite i are evaluated and calculated to obtain the linear system difference solution accuracy of satellite i.

[0166] The linear systematic error evaluation model is expressed as:

[0167]

[0168] In the formula, The linear systematic error solution accuracy of satellite i is represented by , where a, b, c, and d represent the linear parameters of satellite i, and scid represents the satellite number. JudP(scid) is a parity function for determining whether scid is odd or even. When scid is odd, JudP(scid) is -1, and when scid is even, JudP(scid) is 1.

[0169] It should be noted that, Together, they serve as the accuracy of the linear systematic difference solution for the relative right ascension of satellite i; Together, they serve as the accuracy of the linear systematic difference solution for the relative declination of satellite i.

[0170] S523. Repeat S521 to S522 until the linear system difference calculation accuracy of all satellites is completed.

[0171] S53. Evaluate and process the periodic characteristics in the system difference characteristics to obtain the accuracy of the periodic system difference solution, specifically:

[0172] S531. Based on the aforementioned system difference characteristics, obtain the periodic parameters of satellite i;

[0173] S532. Using the periodic systematic difference evaluation model, the periodic parameters of satellite i are evaluated and calculated to obtain the periodic systematic difference solution accuracy of satellite i.

[0174] The periodic systematic error evaluation model is expressed as:

[0175]

[0176] In the formula, The periodic systematic difference calculation accuracy of satellite i is represented by , e, f, g, and h represent the periodic parameters of satellite i, and scid represents the satellite number; JudP(scid) is a parity function to determine whether scid is odd or even. When scid is odd, JudP(scid) is -1, and when scid is even, JudP(scid) is 1.

[0177] It should be noted that, Together, they contribute to the accuracy of the relative right ascension periodic systematic difference solution for satellite i; Together, they contribute to the accuracy of the relative declination periodic systematic difference solution for satellite i.

[0178] S533, repeat S531 to S532 until the periodic systematic difference calculation accuracy of all satellites is completed.

[0179] S54. The accuracy of the constant systematic difference calculation, the accuracy of the linear systematic difference calculation, and the accuracy of the periodic systematic difference calculation are comprehensively processed to obtain systematic difference accuracy evaluation information.

[0180] Example 2

[0181] Please see Figure 3 . Figure 3 This is a schematic diagram of a space-based directional observation data systematic difference calculation device disclosed in an embodiment of the present invention. Figure 3 The described apparatus can be applied in management systems, such as local servers or cloud servers for management, and the embodiments of the present invention are not limited thereto. Figure 3 As shown, the device may include:

[0182] The stellar angular distance measurement data acquisition module 201 is used to acquire a set of stellar angular distance measurement data; the stellar angular distance measurement data includes the relative right ascension and relative declination observation values ​​between the observing satellite and the observed satellite; the observing satellite is a BeiDou IGSO satellite, and the observed satellite is a BeiDou MEO satellite; the stellar angular distance measurement data set includes relative right ascension and relative declination observation values ​​with an observation duration of not less than 12 hours;

[0183] The stellar angular distance truth value calculation module 202 is used to calculate and process the precise ephemeris of the BeiDou satellite to obtain a set of stellar angular distance truth values; the stellar angular distance truth values ​​include the relative right ascension truth value and the relative declination truth value; the precise ephemeris of the BeiDou satellite is obtained from the MGEX system.

[0184] The observation data systematic difference calculation module 203 is used to process the set of stellar angular distance measurement data and the set of true stellar angular distance values ​​to obtain the observation data systematic difference;

[0185] The systematic difference characteristic analysis module 204 is used to perform error calculation processing on the systematic difference of the observation data to obtain the systematic difference characteristics; the systematic difference characteristics include constant characteristics, linear characteristics and periodic characteristics;

[0186] The evaluation module 205 is used to evaluate the system difference characteristics and obtain system difference accuracy evaluation information.

[0187] This second embodiment is the product embodiment corresponding to the first embodiment. The steps and methods included are the same as those in the first embodiment, and will not be described in detail in the second embodiment.

[0188] Example 3

[0189] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of another space-based directional observation data systematic difference calculation device disclosed in an embodiment of the present invention. Wherein, Figure 4The described apparatus can be applied in management systems, such as local servers or cloud servers for management, and the embodiments of the present invention are not limited thereto. Figure 4 As shown, the device may include:

[0190] Memory 301 storing executable program code;

[0191] Processor 302 coupled to memory 301;

[0192] The processor 302 calls the executable program code stored in the memory 301 to execute the steps in the method for solving the systematic difference of space-based directional observation data described in Embodiment 1.

[0193] The device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0194] Through the detailed description of the above embodiments, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, including read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically-Erasable Programmable Read-Only Memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, disk storage, magnetic tape storage, or any other computer-readable medium that can be used to carry or store data.

[0195] Finally, it should be noted that the method and apparatus for calculating the systematic difference of space-based directional observation data disclosed in the embodiments of the present invention are merely preferred embodiments of the present invention and are only used to illustrate the technical solutions of the present invention, not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the systematic difference of space-based directional observation data, characterized in that, The method includes: S1. Obtain a set of stellar angular distance measurement data; the stellar angular distance measurement data includes the relative right ascension and relative declination observation values ​​between the observing satellite and the observed satellite; the observing satellite is a BeiDou IGSO satellite, and the observed satellite is a BeiDou MEO satellite; the stellar angular distance measurement data set includes the relative right ascension and relative declination observation values ​​with an observation duration of not less than 24 hours; S2. Calculate and process the precise ephemeris of the BeiDou satellites to obtain a set of true values ​​for stellar angular distances; the true values ​​for stellar angular distances include true values ​​for relative right ascension and relative declination; the precise ephemeris of the BeiDou satellites is obtained from the MGEX system. S3. Process the set of stellar angular distance measurement data and the set of stellar angular distance true values ​​to obtain the systematic difference of the observation data; S4. Perform error calculation on the systematic error of the observed data to obtain the systematic error characteristics; the systematic error characteristics include constant characteristics, linear characteristics, and periodic characteristics; S5. Evaluate the system difference characteristics to obtain system difference accuracy evaluation information; In step S4, the systematic error calculation processing of the observed data to obtain the systematic error characteristics includes: S41. Using the constant deviation solution model, the systematic error of the observation data is processed to obtain the constant characteristics of each satellite; The constant deviation calculation model is expressed as follows: In the formula, i represents the satellite number. The relative equatorial constant characteristic of satellite i is represented by M, which represents the number of epochs in which the systematic difference of satellite i's observation data is collected within the observation period. This represents the difference in right ascension relative to the system at the m-th epoch of satellite i; This indicates the relative latitude and longitude characteristics of satellite i. This represents the difference in latitude and longitude relative to the latitude and longitude system at the m-th epoch of satellite i; S42. Using the systematic difference of the observation data, solve the preset linear error model of the observation values ​​to obtain the linear characteristics of each satellite; The preset linear error model for the observed values ​​is expressed as follows: In the formula, i represents the satellite number. This indicates the linearity of the relative right ascension of satellite i. This represents the relative latitude and longitude linearity of satellite i, where t represents the observation time, and a... i b i c i d i Let represent the linear parameters of satellite i, respectively; S43. Using the systematic difference of the observation data, solve the preset periodic error model of the observation values ​​to obtain the periodic characteristics of each satellite. The preset periodic error model of the observed values ​​is expressed as follows: In the formula, i represents the satellite number. This indicates the periodicity of the relative right ascension of satellite i. The relative latitude and longitude periodicity of satellite i is represented by t, which represents the observation time, and e is the periodicity of ... i f i g i h i These represent the periodic parameters of satellite i.

2. The method for calculating the systematic difference of space-based directional observation data according to claim 1, characterized in that, The set of stellar angular distance measurement data includes: S11. Establish a staring link between the observation satellite and the observed satellite; the observation satellite includes 3 BeiDou IGSO satellites; the observed satellite includes 28 MEO satellites, distributed in 3 orbital planes, with each orbit corresponding to 3 BeiDou IGSO satellites; each BeiDou IGSO satellite establishes a fixed observation link with one visible MEO satellite in the observed orbit, and when the visible MEO satellite becomes invisible, switch to other visible MEO satellites in the same orbital plane; S12. Within the preset observation duration and at preset observation intervals, the BeiDou IGSO satellite is used to continuously conduct observations and obtain a set of stellar angular distance measurement data. Each observation data includes 3 stellar angular distance measurement data, and each BeiDou IGSO satellite obtains 1 stellar angular distance measurement data.

3. The method for calculating the systematic difference of space-based directional observation data according to claim 1, characterized in that, The calculation and processing of the precise ephemeris of the BeiDou satellites yields a true set of stellar angular distances, including: S21. Obtain the precise ephemeris of the BeiDou satellite from the MGEX system; the precise ephemeris of the BeiDou satellite corresponds to the observation time of the set of stellar angular distance measurement data. S22. Using the true value calculation model of stellar angular distance, the precise ephemeris of the Beidou satellite is processed to obtain the true value set of stellar angular distance; The true value calculation model expression for stellar angular distance is as follows: In the formula, and These are the true values ​​of the relative right ascension and relative declination between the observed satellite i and the observed satellite j, respectively. and The position vectors of satellite i and observed satellite j in the inertial coordinate system are observed respectively.

4. The method for calculating the systematic difference of space-based directional observation data according to claim 1, characterized in that, The process of processing the set of stellar angular distance measurement data and the set of true stellar angular distance values ​​to obtain the systematic error of the observation data includes: S31. Construct an observation model based on stellar angular distance measurement data and true stellar angular distance values; The observation model is represented as follows: In the formula, and These are the relative right ascension and relative declination observations, respectively. and These represent the true relative right ascension and true relative declination between IGSO observation satellite i and observed MEO satellite j in the celestial coordinate system. and The relative right ascension error and relative declination error of the BeiDou IGSO satellite. and The relative right ascension error and relative declination error of the BeiDou MEO satellite are given; both of these errors include system error and Gaussian white noise. S32. Apply error constraints to the observation model; S33. Based on the error constraint, the observation model is used to process the stellar angular distance measurement data set to generate observation error values; the observation error values ​​include constant observation deviation values, linear observation error values, and periodic observation error values; S34. Based on the observation error value, the observation model is used to solve the set of stellar angular distance measurement data and the set of true stellar angular distance values ​​to obtain the observation data systematic error; the observation data systematic error includes the relative right ascension systematic error and the relative declination systematic error.

5. The method for calculating the systematic difference of space-based directional observation data according to claim 4, characterized in that, Error constraints are applied to the observation model, specifically: S321. The relative difference in right ascension and relative difference in declination must satisfy the following conditions: In the formula, p represents the satellite number, and N represents the number of BeiDou satellites used for space-based orientation measurement; and The relative right ascension error and relative declination error of satellite p; the and There are three forms of manifestation: constant deviation, linear error, and periodic error, as described in S322, S323, and S324. S322, The constant deviation of the observation model is: in, Indicates the satellite's relative declination constant deviation. This represents the satellite's relative declination constant deviation, and scid represents the satellite number; JudP(scid) is a parity function to determine whether scid is odd or even. When scid is odd, JudP(scid) is -1, and when scid is even, JudP(scid) is 1. and These are Gaussian white noises with respect to relative right ascension and relative declination, respectively, under constant deviation. S323, The linearity error of the observation model is: In the formula, Indicates the relative right ascension linearity error. This represents the linear error relative to declination, where t is the observation time; and These are Gaussian white noises with respect to relative right ascension and relative declination, respectively, under linear error conditions. S324, The periodic error of the observation model is: In the formula, This indicates the periodicity error relative to right ascension. This indicates the periodicity error relative to declination. and These are Gaussian white noises with respect to relative right ascension and relative declination, respectively, under periodic deviation.

6. The method for calculating the systematic difference of space-based directional observation data according to claim 4, characterized in that, Based on the observation error value, the observation model is used to solve the stellar angular distance measurement data set and the true stellar angular distance set to obtain the observation data systematic error, including: S341. Obtain stellar angular distance measurement data for any observation epoch k from the set of stellar angular distance measurement data. S342. Obtain the true value of stellar angular distance corresponding to any observation epoch k from the set of true values ​​of stellar angular distance; S343. Based on the aforementioned observation model, using the least squares algorithm, calculate the stellar angular distance measurement data and the true value of the stellar angular distance for any observation epoch, and obtain the systematic difference in relative right ascension between the observed satellite and the observed satellite at that observation epoch k. Relative declination system difference S344. Repeat steps S341 to S343 to calculate the relative right ascension systematic difference and relative declination systematic difference for each satellite corresponding to all observation epochs, and obtain the systematic difference of the observation data.

7. The method for calculating the systematic difference of space-based directional observation data according to claim 1, characterized in that, The evaluation process for the system difference characteristics to obtain system difference accuracy evaluation information includes: S51. Evaluate the constant characteristics in the system difference characteristics to obtain the constant system difference solution accuracy; S52. Evaluate the linearity of the system difference characteristics to obtain the linear system difference solution accuracy. S53. Evaluate and process the periodic characteristics in the system difference characteristics to obtain the periodic system difference solution accuracy.

8. A system difference calculation device for space-based directional observation data, characterized in that, The apparatus employing the systematic difference calculation method for space-based directional observation data as described in any one of claims 1-7 comprises: The stellar angular distance measurement data acquisition module is used to acquire a set of stellar angular distance measurement data; the stellar angular distance measurement data includes the relative right ascension and relative declination observation values ​​between the observing satellite and the observed satellite; the observing satellite is a BeiDou IGSO satellite, and the observed satellite is a BeiDou MEO satellite; The stellar angular distance truth value calculation module is used to calculate and process the precise ephemeris of BeiDou satellites to obtain a set of stellar angular distance truth values; the stellar angular distance truth values ​​include relative right ascension truth values ​​and relative declination truth values; the precise ephemeris of BeiDou satellites is obtained from the MGEX system; The observation data systematic difference calculation module is used to process the set of stellar angular distance measurement data and the set of true stellar angular distance values ​​to obtain the observation data systematic difference; The systematic error characteristic analysis module is used to perform error calculation on the systematic error of the observed data to obtain the systematic error characteristics; the systematic error characteristics include constant characteristics, linear characteristics, and periodic characteristics; The evaluation module is used to evaluate the system difference characteristics and obtain system difference accuracy evaluation information.

9. A system difference calculation device for space-based directional observation data, characterized in that, The device includes: Memory containing executable program code; A processor coupled to the memory; The processor calls the executable program code stored in the memory to execute the systematic difference calculation method for space-based directional observation data as described in any one of claims 1-7.

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