A method and system for selecting a navigation star for starlight correction of a space vehicle

Abstract

This invention discloses a method and system for selecting navigation stars for starlight correction in spacecraft. The method includes: determining the ecliptic plane normal vector based on the unit direction vector of the sun's position at different times; selecting candidate navigation stars and background stars; calculating the angle between each star in the candidate navigation stars and the ecliptic plane, and determining a preliminary navigation star from the candidate navigation stars based on the angle; determining the first diagonal distance between each star in the preliminary navigation stars and each star in the background stars based on the direction vectors of the positions of the preliminary navigation stars and the background stars; determining candidate navigation stars from the preliminary navigation stars based on the first diagonal distance; within the candidate navigation stars, recalculating the second diagonal distance between each candidate navigation star and the remaining candidate navigation stars, and determining the final navigation star based on the second diagonal distance. This invention solves the problem that, due to the influence of planetary celestial light and Earth shadows, a new navigation star needs to be selected for starlight correction for different flight missions and different flight start times of spacecraft.

Description

Technical Field

[0001] This invention relates to the field of spacecraft navigation, and in particular to a method and system for selecting navigation stars for spacecraft starlight correction. Background Technology

[0002] When spacecraft perform starlight corrections for different missions and at different flight start times, the navigation stars must be reselected on the ground in advance based on the theoretical orbit due to the influence of planets, celestial light, and terrestrial shadows, which is time-consuming and labor-intensive. Therefore, it is urgent to study a navigation star selection strategy that selects a number of navigation stars in the entire sky for spacecraft to use for starlight corrections for different missions and at different flight start times. Summary of the Invention

[0003] This invention discloses a method and system for selecting a navigation star for starlight correction of a spacecraft, which solves the problem that the navigation star needs to be reselected when the spacecraft performs starlight correction for different flight missions and different flight start times due to the influence of planets, celestial light and terrestrial shadows.

[0004] The technical solution of this invention is:

[0005] In a first aspect, the present invention discloses a method for selecting navigation stars for starlight correction in spacecraft, comprising:

[0006] Determine the ecliptic plane normal vector based on the unit direction vector of the sun's position in the J2000 geocentric equatorial inertial coordinate system at different times;

[0007] Candidate navigation stars and background stars are selected from the Hipparcos star catalog; the angle between each star in the candidate navigation stars and the ecliptic plane is calculated, and the initial navigation star is determined from the candidate navigation stars based on the angle;

[0008] Based on the direction vectors of the positions of the initial navigation stars and the background stars in the J2000 geocentric equatorial inertial coordinate system, determine the first diagonal distance between each star in the initial navigation stars and each star in the background stars.

[0009] Based on the first diagonal distance, select candidate navigation stars from the initial selection of navigation stars. Among all candidate navigation stars, calculate the second diagonal distance between each candidate navigation star and the remaining candidate navigation stars. Determine the final navigation star based on the second diagonal distance.

[0010] In one specific implementation, the ecliptic plane normal vector is determined based on the unit direction vector of the sun's position in the J2000 geocentric equatorial inertial coordinate system at different times; specifically including:

[0011] Determine the normal vector H of the ecliptic plane as follows: i

[0012] H i =Si1 ×S i2 (1)

[0013] Where the symbol × represents the vector cross product; S i1 S i2 These are the unit direction vectors of the Sun's position in the J2000 geocentric equatorial inertial coordinate system at times t1 and t2, respectively. Time t1 can be arbitrarily chosen, and t2 = t1 + 90 * 86400, in seconds.

[0014] In one specific implementation, candidate navigation stars and background stars are selected from the Hipparcos star catalog; the angle between each star in the candidate navigation stars and the ecliptic plane is calculated, and a preliminary navigation star is determined from the candidate navigation stars based on the angle; specifically including:

[0015] Stars brighter than magnitude 5 were selected from the Hipparcos catalogue, and binary and variable stars were removed. The selected stars were designated as candidate navigation stars and denoted as NavStar5. Stars brighter than magnitude 6 were selected from the Hipparcos catalogue and designated as background stars and denoted as BackStar.

[0016] Determine the angle θ between each star in the candidate navigation star NavStar5 and the ecliptic plane. j

[0017]

[0018] Wherein, the subscript i represents the J2000 geocentric equatorial inertial coordinate system, and the subscript j represents the j-th navigation satellite; θ j The unit is rad; the symbol · represents the vector dot product; Star5 i,j The direction vector of the j-th navigation satellite in NavStar5, a candidate navigation satellite, in the J2000 geocentric equatorial inertial coordinate system is calculated using the following formula:

[0019]

[0020] Where, subscript i represents the J2000 geocentric equatorial inertial coordinate system; subscript j represents the j-th navigation satellite; α j δ j These are the right ascension and declination of the j-th navigation satellite in NavStar5 in the J2000 geocentric equatorial inertial coordinate system, in rad, and are read from the star catalog.

[0021] like or If the unit is rad, then the star is selected as the initial navigation star and denoted as NavStar45.

[0022] In one specific implementation, based on the direction vectors of the positions of the initially selected navigation stars and the background stars in the J2000 geocentric equatorial inertial coordinate system, the first diagonal distance between each star in the initially selected navigation stars and each star in the background stars is determined; specifically including:

[0023] The diagonal distance θ between the first star of each star in the initial navigation star NavStar45 and the first star of each star in the background star BackStar is determined as follows: m,n ,

[0024] θ m,n =acos(NavStar45) i,m ·BackStar i,n (5)

[0025] Among them, NavStar45 i,m The direction vector of the position of the m-th navigation star in the initial navigation star NavStar45 in the J2000 geocentric equatorial inertial coordinate system is determined by equation (4); BackStar i,n Let be the direction vector of the position of the nth star in the background star BackStar in the J2000 geocentric equatorial inertial coordinate system, which is determined by equation (4); the symbol · represents the vector dot product.

[0026] In one specific implementation, candidate navigation stars are determined from the initial pool of candidate navigation stars based on the first diagonal distance. Then, among all candidate navigation stars, the second diagonal distance between each candidate navigation star and the remaining candidate navigation stars is calculated again. The final navigation star is determined based on the second diagonal distance. Specifically, this includes:

[0027] If a star in NavStar45 is at least 0.5 magnitude brighter than a star in BackStar whose diagonal distance from it is less than 5°, then that star will be initially considered as a candidate navigation star.

[0028] Calculate the diagonal distance between each of the candidate navigation stars and the second star of the remaining candidate navigation stars using formula (5). If the diagonal distance of the second star is less than... If the navigation star is removed, the remaining navigation stars are the final determined navigation stars.

[0029] Secondly, this invention discloses a navigation star selection system for starlight correction in spacecraft, comprising:

[0030] The preprocessing unit is used to determine the ecliptic plane normal vector based on the unit direction vector of the sun's position in the J2000 geocentric equatorial inertial coordinate system at different times;

[0031] The filtering unit is used to filter candidate navigation stars and background stars from the Hipparcos star catalog; calculate the angle between each star in the candidate navigation stars and the ecliptic plane, and determine the initial navigation star from the candidate navigation stars based on the angle;

[0032] The star diagonal distance calculation unit is used to determine the first star diagonal distance between each star in the initial navigation star and each star in the background star based on the direction vector of the position of the initial navigation star and the background star in the J2000 geocentric equatorial inertial coordinate system.

[0033] The determining unit is used to determine the candidate navigation star from the initial selection of navigation stars based on the first star diagonal distance. Among all the candidate navigation stars, the second star diagonal distance between each candidate navigation star and the other candidate navigation stars is calculated again, and the final navigation star is determined based on the second star diagonal distance.

[0034] Thirdly, a computing device is provided, comprising at least one processor and at least one memory, wherein the memory stores a computer program, and the processor is configured to read the computer program from the memory and execute any step of the method described in the first aspect.

[0035] Fourthly, a computer-readable storage medium is provided, the computer-readable storage medium storing computer-executable instructions for causing a computer to perform any step of the method described in the first aspect.

[0036] The beneficial technical effects of this invention are:

[0037] This invention proposes a navigation star selection strategy for starlight correction of spacecraft, which solves the problem that the navigation star needs to be reselected when the spacecraft performs starlight correction for different flight missions and different flight start times due to the influence of planets, celestial light and terrestrial shadows.

[0038] This invention proposes a navigation star selection strategy, specifically a navigation star selection strategy for starlight correction of spacecraft. This method selects a certain number of navigation stars across the entire sky using this strategy, ensuring that the spacecraft can observe at least one pair of navigation stars that meet the requirements of sky-to-ground shadow at any location and at any time. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of an Earth region according to an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of a navigation star selection method for starlight correction of a spacecraft according to an embodiment of the present invention. Detailed Implementation

[0041] To address the issue that spacecraft need to reselect a navigation star for starlight correction due to the influence of planets, celestial shadows, and other factors at different flight missions and start times, embodiments of this invention provide a method and system for selecting a navigation star for spacecraft starlight correction.

[0042] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0043] In this article, "multiple or several" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0044] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention. Furthermore, the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0045] Example 1

[0046] like Figure 1 The diagram shown is a schematic representation of an Earth region according to an embodiment of the present invention. Figure 2 This is a schematic diagram of a navigation star selection method for starlight correction of a spacecraft according to an embodiment of the present invention.

[0047] The J2000 geocentric equatorial inertial coordinate system used in this article adopts the industry-standard description method and will not be elaborated further.

[0048] The Hipparcos catalogue is a major achievement of the European Space Agency's Hipparcos Astrometry Satellite Program. The 23rd International Astronomical Union resolved in 1998 to adopt the Hipparcos catalogue system as a reference system for optical observations. Navigation stars were selected from the Hipparcos catalogue for this purpose.

[0049] The solar obscuration angle of a spacecraft's visible light imager is generally required to be no less than 45°, the lunar obscuration angle no less than 30°, and the angle between the orbital plane of a planet or the Moon and the ecliptic plane is less than 10°. Therefore, as long as the navigation star is selected within a region where the angle with the ecliptic plane is greater than 45°, the influence of the Sun, Moon, and planets on the visible light imager can be avoided, allowing the spacecraft to perform starlight correction at any time and any location. To ensure that the navigation stars in the Northern and Southern Hemispheres can form a navigation star pair, the angle between the navigation star and the ecliptic plane should not be too large. After comprehensive consideration, the range of the angle between the navigation star and the ecliptic plane is selected as [45°, 65°].

[0050] A method for selecting navigation stars for starlight correction in spacecraft, comprising:

[0051] S11. Determine the ecliptic plane normal vector based on the unit direction vector of the sun's position in the J2000 geocentric equatorial inertial coordinate system at different times;

[0052] In this step, the normal vector H of the ecliptic plane is calculated. i

[0053] H i =S i1 ×S i2 (1)

[0054] Where the symbol × represents the vector cross product; S i1 S i2 Let t1 and t2 be the unit direction vectors of the Sun's position in the J2000 geocentric equatorial inertial coordinate system, respectively. The time t1 can be arbitrarily chosen, and t2 = t1 + 90 * 86400, in seconds. The formula for calculating the unit direction vector of the Sun's position in the J2000 geocentric equatorial inertial coordinate system is as follows:

[0055]

[0056] Among them, e s =0.0167086741 is the solar orbital eccentricity; i s =0.409093096 is the solar orbital inclination, in rad; ω s =-1.3450356 is the solar perigee argument at midnight 2017, in rad; M s,0 =6.2446201003039 is the mean solar anomaly angle at midnight in 2017, in rad; Δt is the solar mean velocity, in rad / s; Δt is the time difference between the current time and midnight 2017, in seconds; M s The angle of the sun's mean aperitone at the time of observation; u s The solar latitude argument at the time of observation; the symbol |||| represents the vector magnitude.

[0057] S12. Select candidate navigation stars and background stars from the Hipparcos star catalog; calculate the angle between each star in the candidate navigation stars and the ecliptic plane, and determine the initial navigation star from the candidate navigation stars based on the angle;

[0058] In this step, stars brighter than magnitude 5 are selected from the Hipparcos catalogue, and binary and variable stars are removed. The selected stars are designated as candidate navigation stars and denoted as NavStar5. Stars brighter than magnitude 6 are selected from the Hipparcos catalogue and designated as background stars and denoted as BackStar.

[0059] Calculate the angle θ between each star in the candidate navigation star NavStar5 and the ecliptic plane. j

[0060]

[0061] Wherein, the subscript i represents the J2000 geocentric equatorial inertial coordinate system, and the subscript j represents the j-th navigation satellite; θ j The unit is rad; the symbol · represents the vector dot product; Star5 i,j The direction vector of the j-th navigation satellite in NavStar5, a candidate navigation satellite, in the J2000 geocentric equatorial inertial coordinate system is calculated using the following formula:

[0062]

[0063] Where, subscript i represents the J2000 geocentric equatorial inertial coordinate system; subscript j represents the j-th navigation satellite; α j δ j These are the right ascension and declination of the j-th navigation satellite in NavStar5 in the J2000 geocentric equatorial inertial coordinate system, in rad, which can be read from the star catalog.

[0064] like or If the unit is rad, then the star is selected as the initial navigation star and denoted as NavStar45.

[0065] S13. Based on the direction vectors of the positions of the initial navigation stars and the background stars in the J2000 geocentric equatorial inertial coordinate system, determine the first diagonal distance between each star in the initial navigation stars and each star in the background stars.

[0066] In this step,

[0067] Calculate the first diagonal distance θ between each star in the initial navigation star NavStar45 and each star in the background star BackStar. m,n ,

[0068] θ m,n=acos(NavStar45) i,m ·BackStar i,n (5)

[0069] Among them, NavStar45 i,m The direction vector of the position of the m-th navigation star in the initially selected navigation star NavStar45 in the J2000 geocentric equatorial inertial coordinate system is calculated by equation (4); BackStar i,n Let be the direction vector of the position of the nth star in the background star BackStar in the J2000 geocentric equatorial inertial coordinate system, calculated by equation (4); the symbol · represents the vector dot product.

[0070] S14. Based on the first diagonal distance, determine the candidate navigation stars from the initial selection of navigation stars. Among all the candidate navigation stars, recalculate the second diagonal distance between each candidate navigation star and the other candidate navigation stars. Determine the final navigation star based on the second diagonal distance.

[0071] In this step, if a star in NavStar45 is at least 0.5 magnitude brighter than a star in BackStar whose diagonal distance from its first star is less than 5°, then that star will be initially selected as a potential navigation star.

[0072] Calculate the diagonal distance between each of the candidate navigation stars and the second star of the remaining candidate navigation stars using formula (5). If the diagonal distance is less than... If the navigation star is removed, the remaining navigation stars are the final determined navigation stars.

[0073] Through the above steps, a navigation star selection strategy for starlight correction of spacecraft was realized.

[0074] This invention proposes a navigation star selection strategy, specifically a navigation star selection strategy for starlight correction in spacecraft. This method selects a certain number of navigation stars across the entire sky using this strategy, ensuring that the spacecraft can observe at least one pair of navigation stars that meet the requirements of sky-ground shadow at any location and at any time. First, the ecliptic plane is determined. Then, stars brighter than magnitude 5 with angles between 45° and 65° and -65° and -45° to the ecliptic plane are selected as initial navigation stars, and stars brighter than magnitude 6 are selected as background stars. Finally, from the initial navigation stars, stars with a diagonal distance of less than 5° from the background stars and brighter than the background stars by at least 0.5 magnitudes are selected, and navigation stars with diagonal distances of less than 10° between any two stars are removed. The remaining navigation stars are the final determined navigation stars.

[0075] Example 2

[0076] The J2000 geocentric equatorial inertial coordinate system used in this article adopts the industry-standard description method and will not be elaborated further.

[0077] The Hipparcos catalogue is a major achievement of the European Space Agency's Hipparcos Astrometry Satellite Program. The 23rd International Astronomical Union resolved in 1998 to adopt the Hipparcos catalogue system as a reference system for optical observations. Navigation stars were selected from the Hipparcos catalogue for this purpose.

[0078] The solar obscuration angle of a spacecraft's visible light imager is generally required to be no less than 45°, the lunar obscuration angle no less than 30°, and the angle between the orbital plane of a planet or the Moon and the ecliptic plane is less than 10°. Therefore, as long as the navigation star is selected within a region where the angle with the ecliptic plane is greater than 45°, the influence of the Sun, Moon, and planets on the visible light imager can be avoided, allowing the spacecraft to perform starlight correction at any time and any location. To ensure that the navigation stars in the Northern and Southern Hemispheres can form a navigation star pair, the angle between the navigation star and the ecliptic plane should not be too large. After comprehensive consideration, the range of the angle between the navigation star and the ecliptic plane is selected as [45°, 65°].

[0079] The specific steps of a method for selecting navigation stars for starlight correction in spacecraft are as follows:

[0080] The first step is to determine the ecliptic plane.

[0081] Calculate the normal vector H of the ecliptic plane i

[0082] H i =S i1 ×S i2 (1)

[0083] Where the symbol × represents the vector cross product; S i1 S i2 Let t1 and t2 be the unit direction vectors of the Sun's position in the J2000 geocentric equatorial inertial coordinate system, respectively. The time t1 can be arbitrarily chosen, and t2 = t1 + 90 * 86400, in seconds. The formula for calculating the unit direction vector of the Sun's position in the J2000 geocentric equatorial inertial coordinate system is as follows:

[0084]

[0085] Among them, e s =0.0167086741 is the solar orbital eccentricity; i s =0.409093096 is the solar orbital inclination, in rad; ω s =-1.3450356 is the solar perigee argument at midnight 2017, in rad; M s,0 =6.2446201003039 is the mean solar anomaly angle at midnight in 2017, in rad; Δt is the solar mean velocity, in rad / s; Δt is the time difference between the current time and midnight 2017, in seconds; M s The angle of the sun's mean aperitone at the time of observation; u s The solar latitude argument at the time of observation; the symbol |||| represents the vector magnitude.

[0086] The second step is preliminary screening of navigation stars.

[0087] Stars brighter than magnitude 5 were selected from the Hipparcos catalogue, excluding binary and variable stars. The selected stars were designated as candidate navigation stars and denoted as NavStar5. Stars brighter than magnitude 6 were selected from the Hipparcos catalogue and designated as background stars and denoted as BackStar.

[0088] Calculate the angle θ between each star in the candidate navigation star NavStar5 and the ecliptic plane. j

[0089]

[0090] Wherein, the subscript i represents the J2000 geocentric equatorial inertial coordinate system, and the subscript j represents the j-th navigation satellite; θ j The unit is rad; the symbol · represents the vector dot product; Star5 i,j The direction vector of the j-th navigation satellite in NavStar5, a candidate navigation satellite, in the J2000 geocentric equatorial inertial coordinate system is calculated using the following formula:

[0091]

[0092] Where, subscript i represents the J2000 geocentric equatorial inertial coordinate system; subscript j represents the j-th navigation satellite; α j δ j These are the right ascension and declination of the j-th navigation satellite in NavStar5 in the J2000 geocentric equatorial inertial coordinate system, in rad, which can be read from the star catalog.

[0093] like or If the unit is rad, then the star is selected as the initial navigation star and denoted as NavStar45.

[0094] The third step is to finally select the navigation star.

[0095] Calculate the diagonal distance θ between each star in the initial navigation star NavStar45 and each star in the background star BackStar. m,n ,

[0096] θ m,n =acos(NavStar45) i,m ·BackStari,n (5)

[0097] Among them, NavStar45 i,m The direction vector of the position of the m-th navigation star in the initially selected navigation star NavStar45 in the J2000 geocentric equatorial inertial coordinate system is calculated by equation (4); BackStar i,n Let be the direction vector of the position of the nth star in the background star BackStar in the J2000 geocentric equatorial inertial coordinate system, calculated by equation (4); the symbol · represents the vector dot product.

[0098] If a star in NavStar45 is at least 0.5 magnitude brighter than a star in BackStar whose diagonal distance from it is less than 5°, then that star will be initially considered as a candidate navigation star.

[0099] Calculate the diagonal distance between each of the candidate navigation stars and the other candidate navigation stars again using formula (5). If the diagonal distance is less than... If the navigation star is removed, the remaining navigation stars are the final determined navigation stars.

[0100] Through the above steps, a navigation star selection strategy for starlight correction of spacecraft was realized.

[0101] This invention proposes a navigation star selection strategy, specifically a navigation star selection strategy for starlight correction in spacecraft. This method selects a certain number of navigation stars across the entire sky using this strategy, ensuring that the spacecraft can observe at least one pair of navigation stars that meet the requirements of sky-ground shadow at any location and at any time. First, the ecliptic plane is determined. Then, stars brighter than magnitude 5 with angles between 45° and 65° and -65° and -45° to the ecliptic plane are selected as initial navigation stars, and stars brighter than magnitude 6 are selected as background stars. Finally, from the initial navigation stars, stars with a diagonal distance of less than 5° from the background stars and brighter than the background stars by at least 0.5 magnitudes are selected, and navigation stars with diagonal distances of less than 10° between any two stars are removed. The remaining navigation stars are the final determined navigation stars.

[0102] This invention proposes a navigation star selection strategy for starlight correction of spacecraft, which solves the problem that the navigation star needs to be reselected when the spacecraft performs starlight correction for different flight missions and different flight start times due to the influence of planets, celestial light and terrestrial shadows.

[0103] Based on the same technical concept, this application also provides a navigation star selection device for starlight correction of a spacecraft. Since the principle of the above device in solving the problem is similar to that of a navigation star selection method for starlight correction of a spacecraft, the implementation of the above device can refer to the implementation of the method, and the repeated parts will not be described again.

[0104] A navigation star selection system for starlight correction in a spacecraft includes:

[0105] The preprocessing unit is used to determine the ecliptic plane normal vector based on the unit direction vector of the sun's position in the J2000 geocentric equatorial inertial coordinate system at different times;

[0106] The filtering unit is used to filter candidate navigation stars and background stars from the Hipparcos star catalog; calculate the angle between each star in the candidate navigation stars and the ecliptic plane, and determine the initial navigation star from the candidate navigation stars based on the angle;

[0107] The star diagonal distance calculation unit is used to determine the first star diagonal distance between each star in the initial navigation star and each star in the background star based on the direction vector of the position of the initial navigation star and the background star in the J2000 geocentric equatorial inertial coordinate system.

[0108] The determining unit is used to determine the candidate navigation star from the initial selection of navigation stars based on the first star diagonal distance. Among all the candidate navigation stars, the second star diagonal distance between each candidate navigation star and the other candidate navigation stars is calculated again, and the final navigation star is determined based on the second star diagonal distance.

[0109] For ease of description, the above sections are divided into modules (or units) according to their functional modules and described separately. Of course, in implementing this invention, the functions of each module (or unit) can be implemented in one or more software or hardware components.

[0110] Based on the same technical concept, the present invention provides a computing device, including at least one processor and at least one memory, wherein the memory stores a computer program, and the processor is used to read the computer program in the memory and execute a navigation star selection method for starlight correction of a spacecraft.

[0111] Based on the same technical concept, the present invention provides a computer-readable storage medium storing computer-executable instructions for causing a computer to execute a navigation star selection method for starlight correction of a spacecraft.

[0112] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for selecting navigation stars for starlight correction in spacecraft, characterized in that, include: Determine the ecliptic plane normal vector based on the unit direction vector of the sun's position in the J2000 geocentric equatorial inertial coordinate system at different times; Specifically, it includes: Determine the normal vector of the ecliptic plane as follows: (1) Among them, symbols For vector cross product; , They are respectively time, The unit direction vector of the sun's position in the J2000 geocentric equatorial inertial coordinate system at any given moment. The time can be selected at any time. Unit: s; Candidate navigation stars and background stars are selected from the Hipparcos star catalog; the angle between each star in the candidate navigation stars and the ecliptic plane is calculated, and a preliminary navigation star is determined from the candidate navigation stars based on the angle; specifically, this includes: Stars brighter than magnitude 5 were selected from the Hipparcos catalogue, excluding binary and variable stars. The selected stars were used as candidate navigation stars and denoted as . NavStar 5; Select stars brighter than magnitude 6 from the Hipparcos catalogue. These selected stars will be used as background stars and denoted as _____. BackStar ; Identify alternative navigation stars NavStar The angle between each star and the ecliptic plane in the 5th case (3) Among them, subscript i Indicates the J2000 geocentric equatorial inertial coordinate system, subscript j Indicates the first j One navigation satellite; The unit is rad; symbol Dot product of vectors; As alternative navigation stars NavStar 5th j The direction vector of the navigation satellite's position in the J2000 geocentric equatorial inertial coordinate system is calculated using the following formula: (4) Among them, subscript i Indicates the J2000 geocentric equatorial inertial coordinate system; subscript j Indicates the first j One navigation satellite; , They are respectively NavStar 5th j The right ascension and declination of each navigation satellite in the J2000 geocentric equatorial inertial coordinate system, in rad, are read from the satellite catalog. like or If the unit is rad, then this star is selected as the initial navigation star and denoted as . NavStar 45; Based on the direction vectors of the positions of the initial navigation stars and the background stars in the J2000 geocentric equatorial inertial coordinate system, determine the first diagonal distance between each star in the initial navigation stars and each star in the background stars. Based on the first diagonal distance, select candidate navigation stars from the initial selection of navigation stars. Among all candidate navigation stars, calculate the second diagonal distance between each candidate navigation star and the remaining candidate navigation stars. Determine the final navigation star based on the second diagonal distance.

2. The method according to claim 1, characterized in that, Based on the direction vectors of the positions of the initially selected navigation stars and the background stars in the J2000 geocentric equatorial inertial coordinate system, determine the first diagonal distance between each star in the initially selected navigation stars and each star in the background stars; specifically including: The initial navigation star was determined as follows: NavStar Each of the 45 stars and background stars BackStar The first star diagonal distance of each star in the middle , (5) in, For the initial selection of navigation stars NavStar 45th m The direction vector of the position of the navigation satellite in the J2000 geocentric equatorial inertial coordinate system is determined by equation (4); Background stars BackStar The Middle n The direction vector of the position of the star in the J2000 geocentric equatorial inertial coordinate system is determined by equation (4); symbol This is the dot product of vectors.

3. The method according to claim 2, characterized in that, Based on the first diagonal distance, candidate navigation stars are determined from the initial pool of candidate navigation stars. Then, among all candidate navigation stars, the second diagonal distance between each candidate navigation star and the remaining candidate navigation stars is calculated again. The final navigation star is determined based on this second diagonal distance. Specifically, this includes: like NavStar The brightness of a certain star in 45 is higher than BackStar If a star with a magnitude of at least 0.5 is located at an angular distance of less than 5° from its star, it will be initially considered as a candidate navigation star. Calculate the diagonal distance between each of the candidate navigation stars and the second star of the remaining candidate navigation stars using formula (5). If the diagonal distance of the second star is less than... If the value is less than rad, then that navigation star is removed, and the remaining navigation stars are the final determined navigation stars.

4. A navigation star selection system for starlight correction in a spacecraft, characterized in that, include: The preprocessing unit is used to determine the ecliptic plane normal vector based on the unit direction vector of the sun's position in the J2000 geocentric equatorial inertial coordinate system at different times; The preprocessing unit is used to determine the ecliptic plane normal vector in the following manner. (1) Among them, symbols For vector cross product; , They are respectively time, The unit direction vector of the sun's position in the J2000 geocentric equatorial inertial coordinate system at any given moment. The time can be selected at any time. Unit s' The filtering unit is used to filter candidate navigation stars and background stars from the Hipparcos star catalog; calculate the angle between each star in the candidate navigation stars and the ecliptic plane, and determine the initial navigation star from the candidate navigation stars based on the angle; The screening unit is used to select stars brighter than magnitude 5 from the Hipparcos catalogue, and to remove binary stars and variable stars. The selected stars are used as candidate navigation stars, denoted as... NavStar 5; Select stars brighter than magnitude 6 from the Hipparcos catalogue. These selected stars will be used as background stars and denoted as _____. BackStar ; Identify alternative navigation stars NavStar The angle between each star and the ecliptic plane in the 5th case (3) Among them, subscript i Indicates the J2000 geocentric equatorial inertial coordinate system, subscript j Indicates the first j One navigation satellite; The unit is rad; symbol Dot product of vectors; As alternative navigation stars NavStar 5th j The direction vector of the navigation satellite's position in the J2000 geocentric equatorial inertial coordinate system is calculated using the following formula: (4) Among them, subscript i Indicates the J2000 geocentric equatorial inertial coordinate system; subscript j Indicates the first j One navigation satellite; , They are respectively NavStar 5th j The right ascension and declination of each navigation satellite in the J2000 geocentric equatorial inertial coordinate system, in rad, are read from the satellite catalog. like or If the unit is rad, then this star is selected as the initial navigation star and denoted as . NavStar 45; The star diagonal distance calculation unit is used to determine the first star diagonal distance between each star in the initial navigation star and each star in the background star based on the direction vector of the position of the initial navigation star and the background star in the J2000 geocentric equatorial inertial coordinate system. The determining unit is used to determine the candidate navigation star from the initial selection of navigation stars based on the first star diagonal distance. Among all the candidate navigation stars, the second star diagonal distance between each candidate navigation star and the other candidate navigation stars is calculated again, and the final navigation star is determined based on the second star diagonal distance.

5. A computing device, characterized in that, It includes at least one processor and at least one memory, wherein the memory stores a computer program, and the processor is configured to read the computer program from the memory and execute the method according to any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the method described in any one of claims 1 to 3.

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